Check out the following web site:
http://www.mrs-passion.com/SPIP/article.php3?id_article=5
Found a really interesting article (by a French contributor: Dieamond) regarding the difference in the gear ratios between the "original" Japanese (+US) versions and the European version:
http://www.mrs-passion.com/SPIP/article.php3?id_article=5
(Sorry, the site is in French... I will try and post a translation...)
Anyway, me thinks we got the bum deal here... s:cry: :cry: s:cry:
I cannot understand why Toyota did not configure the gear box with 4 short ratios (i.e. max. acceleration) completed with a 5th longer ratio (like an overdrive for eco/motorway driving) s:?: :?: s:?:
Has anyone already changed (or attempted or is thinking of changing) the gear box ratios s:?: :?: s:?:
John
P.S. I search the forum for any articles regarding this topic but did not find anything...
Here are some interesting figures: (perhaps this explains why the US Spyder does a 0-60 in almost half a second less than the Euro version?)
Gear ratios for European and US versions:
Euro US
1, 3.166, 3.166
2, 1.904, 1.904
3, 1.310, 1.392 *
4, 0.969, 1.031 *
5, 0.815, 0.815
Final, 3.941, 4.312 *
* different
I have always thought, shifting from 2nd to 3rd, that the gear was set too "high"... now I can see why!
To get an idea, here are the approximate speeds at 6500rpm for each gear (in km/h) for each configuration:
......................................1........2........3........4........5
Euro: ............................58.....96......140....190....225
Euro + 3rd & 4th US: ...58......96......132....179....225
Euro + US Final: ..........53......88......129....174....206
US: ..............................53......88......121....163....206
According to this article, the US gear ratios can be ordered at Conicelli [unfortunately I could not find them on the web site... need to phone them I guess. However they can also be ordered at your local Toy dealer, but the price is double]
Here are the reference numbers and approx. prices:
Final ratio: 33402-12041 $93.51
3rd ratio: 33034-12130 $80.24
4th ratio: 33035-20170 $80.25
Obviously, changing the gear ratios is not going to be a cheap trip to the garage... (I guess it may require a full engine out operation?)
I wish I could fit the US 3rd, 4th and final drive, but also fit a much longer 5th ratio...
I'd be really interested to know if anyone has attempted to change these ratios...
Cheers
J
Quote from: "phat"Here are some interesting figures: (perhaps this explains why the US Spyder does a 0-60 in almost half a second less than the Euro version?)
No I don't think so as the UK car will get to 60 using only the first two gears, which are the same ratios as the US. Where have you taken the 0-60 times from incidentally?
Quote from: "MRMike"Quote from: "phat"Here are some interesting figures: (perhaps this explains why the US Spyder does a 0-60 in almost half a second less than the Euro version?)
No I don't think so as the UK car will get to 60 using only the first two gears, which are the same ratios as the US. Where have you taken the 0-60 times from incidentally?
Hi there,
Here are some stats (they usually vary between 7.1 and 7.4 s) but this site actually quotes the gear ratios too...
m http://www.supercarstats.com/car/exotic ... ider.shtml (http://www.supercarstats.com/car/exotic-stats/mr2spider.shtml) m
By the way, even though the 1st and 2nd gear ratios are the same, it's the different final ratio that makes the US MR2 Spyder accelerate more than the Euro version (in fact by quite a good margin despite the extra gear change)
IMHO The ideal set up would be 4 short gears followed by a 5th "overdrive" (a bit like the US set up, but with an even longer 5th)...
Looking at the stats, I also noticed the "stock" lateral acceleration of 0.91g. I tested my '2 and it will pull 1.1g with the TTE anti roll bars and fitted with S03s. (I also recorded a maximum lateral accel. of 1.21g... but that was when the car spun off the Circuit du Laquais in France last month ago A beauty to drive!
m http://www.supercarstats.com/car/exotic ... ider.shtml (http://www.supercarstats.com/car/exotic-stats/mr2spider.shtml) m
Quote from: "phat"I cannot understand why Toyota did not configure the gear box with 4 short ratios (i.e. max. acceleration) completed with a 5th longer ratio (like an overdrive for eco/motorway driving) s:?: :?: s:?:
Has anyone already changed (or attempted or is thinking of changing) the gear box ratios s:?: :?: s:?:
John
P.S. I search the forum for any articles regarding this topic but did not find anything...
I would kinda suck, if your speed was too low to use 5th, so you'd have to keep the revs at 4k on 4th s;) ;) s;) Also, what the US gets in acceleration, they lose in high speed, it's always a trade.
I don't think anyone has actually changed the gearing, though some japanese tuners offer new ratios. It's just so much cheaper to get a new (=used) gearbox and get a 6th gear while you're at it.
There's tons of info about this on SC, you might wanna read at least this one:
m http://www.spyderchat.com/phpBB/viewtopic.php?t=144 (http://www.spyderchat.com/phpBB/viewtopic.php?t=144) m
(don't reply to it, that's in the Library)
As a general point the gearing on the '2 does seem very long. 3rd stretches to just under a ton in mine, what are the other 2 gears for then??
It is nice to be able to use third for most of my fast driving and only occasionally have to dip into second rather than constantly moving up and down the box but it does mean the engine is out of the powerband quite a lot (I accept that's often down to me not selecting the right gear for a corner!)
dave.
The greeks people have bought some sets of close ratio gearings from Techno pro spirit.
In France, we measure the 0-100 kph, which is a little bit more than your 0-60 mph.
Unfortunatly, the 2nd hits the rev limiter at 99 kmh.
That's why we have crappy measures s:-( :-( s:-(
But it's true that European gear boxes are longer than US/jap ones.
Maybe you can make a comparison between a real UK MR2 and a grey import.
Thanks for your feedback. I checked the spyderchat forum and found loads of info on the subject.
Funny how so many owners in the US want the Euro GB and vice versa. Maybe I should try a swap s:) :) s:)
Just a dumb question: the final ratio is the ratio between the layshaft and engine shaft (i.e. in the gear box), or is it set by the differential? In other words, is the differential ratio for the US and Euro models the same?
cheers
Quote from: "davejevons"As a general point the gearing on the '2 does seem very long. 3rd stretches to just under a ton in mine, what are the other 2 gears for then??
It is nice to be able to use third for most of my fast driving and only occasionally have to dip into second rather than constantly moving up and down the box but it does mean the engine is out of the powerband quite a lot (I accept that's often down to me not selecting the right gear for a corner!)
dave.
Yes I agree with you, even the third gear is too long, and worst of all, maximum speed in a stock 6 gear car is obtained in 5 gear. The six speed is only for a really economical and boring drive. s:? :? s:?
But, as most of us like to improve the performance of the car, that is just fine. You can add a turbo, get 220hp, and have a final speed of around 250km/h, with the stock 6 speed gearbox. Then, with the big amount of extra torque added, those European stock ratios will work just fine s:wink: :wink: s:wink:
1-100Kmph = 0-62mph IIRC
that's correct darkstar, thats why when they do a 0-100kmh test its quite a few tenths slower than 0-60mph as a lot of cars have to shift up to 3rd to acheive it.
Even if they didn't have to shift, 100-102kmh takes few tenths, since the acceleration gets a bit slower up there. Just as 200-202kmh would be even slower.
I do agree about the too long final gear ratio. I guess the change is all about taxes (here, in France, long ratio gearboxes are less taxed than short, maybe it's the same all around Europe).
It's always funny to think that I'm already over the speed limit when shifting to 4th... (130 kph here in France).
Didn't know about the gearbox tax in France... but not surprised: what haven't they taxed yet!! s:shock: :shock: s:shock: s:lol: :lol: s:lol:
I have been checking out these gear ratios, and I am seriously thinking of getting it done. A friend of a friend who used to be a TTE rally team mechanic, may be able to help me... after all he used to have to do this kind of job in under 30 mins!
What I'm wondering is whether to change only the final ratio (and keep the Euro gears) or to change 3rd & 4th also to a US/J-spec (thus having 4 useable gears rather than just 3 on circuit/mountain road driving)?
I know that the 3rd gear feels like it is set up "too high" on the Euro GB, but with the shorter final ratio, would this still be a problem?
Any ideas?
Cheers
John
3 ideas :
- get TPS gears, but just install 3rd and 4th, as the 5th short would be undrivable (for me)
- swap the whole box to a 6 speed JSpec one
- get more power, then the gear box will be OK s:-D :-D s:-D
Actually, I could care less about 0-100kmh figures, what I care for is overtaking speed, and Euro 3rd gear lets me overtake cars without changing to 4th gear which gives me the best possible in-speed acceleration...
If we had US spec tranny, I would always have to change gears in the middle of overtaking cars or do 80 to 130 in 4th gear (nothing something to be done if you dont have a lot of space for overtaking)...
I dont know what are the speed limits on 2 lane roads in rest of the europe, but here it is 80kmh which means ppl drive around 85kmh (50mph)... so 3rd gear is PERFECT, which is probably what they were thinking of...
Quote from: "spwolf"I dont know what are the speed limits on 2 lane roads in rest of the europe, but here it is 80kmh which means ppl drive around 85kmh (50mph)... so 3rd gear is PERFECT, which is probably what they were thinking of...
They are 80/100kmh over here and I like my gearing they way it is as well s8) 8) s8)
Has anyone got, or does anyone know where to find technical references/manuals regarding the MR2 Roadster (Euro) and MR-S (jap) gearboxes?
I need to find the correct part numbers in order to change the 3rd, 4th and final ratios of my "environmentally uber-friendly euro gear box" s:wink: :wink: s:wink:
Does anyone know if the gear box is included in the Toyota 1ZZ engine workshop manual?
Cheers,
phat (a.k.a. MacSpyder)
Quote from: "phat"Does anyone know if the gear box is included in the Toyota 1ZZ engine workshop manual?
It's not, it's in the Chassis&Body manual.
It doesn't have any part numbers though s:? :? s:?
OK, I have fitted the close ratio C56 transaxle and all I can say is :
WHY? s:roll: :roll: s:roll:
Why the f... did the idiots at Toyota Europe decide to screw up a 100% perfectly tuned gear box (BTW the one that's used everywhere in the world except Europe! s:? :? s:? ) and replace it with a gear box that makes the car feel like an underpowered Toyota Yaris??? Hey, I didn't buy the '2 to go shopping! Verstanden? s:evil: :evil: s:evil:
The figures and all the testimonies pointed the right way: Even TopGear said it when the '2 was launched: The gear ratios (on the C52 Euro gear box) are crap.
The final gear ratio is too small and there's a massive power gap between 2nd and 3rd... Not fun, especially when racing on a track or up a mountain pass.
Well, finally found a C56 from the states, fitted the TorSen LSD (the only good thing about the euro box) and stuck it next to "1zzy"...
The results are simply incredible! It feels like I've got an extra 30bhp to start off with (effect from using the correct final drive ratio!), then shifting through the gears is pure pleasure (the engine is kept in the max power range all the time s:D :D s:D ) Pushing the '2 hard, there's no more hesitation between 2nd and 3rd... This gear box is simply AMAZING s:shock: :shock: s:shock:
Man, this is what the wee engineers who developed the MR2 had originally designed. It was perfect!
I just cannot understand the logic behind the C52 transaxle. If anything could have improved the original C56 gear box, it was simply to add an overdrive (6th gear).
This is simply the best mod anybody can do to his Euro '2... And if I were still living in the UK, I would *definitely* go for a J-spec import (they come fitted with the *right* gear box s:wink: :wink: s:wink: ).
i drive an MRS and have to say that the gearbox is very close ratio. would be interesting to drive a UK spec '2 to feel the difference for myself.
I've compiled a simple table comparing top gear speeds for both transaxles (i.e. 5th gear):
http://www.hanneken.net/MR2/ratios.html
What's interesting is that contrary to what most people think, you don't lose much top speed (about 3 or 4 mph only). This is because the 5th gear on the Euro model works a bit like an overdrive, i.e. it's impossible to reach the red line in 5th, wheras you can with the original C56 gear box.
In Toyota's official "New Car Features" book (Euro version), they quote max speed (210 km/h=131mph) and a max cruising speed: (170km/h=106mph). I figured the max cruising speed for the C56 version is about 10 km/h slower at just under 160 km/h...
Quote from: "phat"This is simply the best mod anybody can do to his Euro '2...
I'd rather get the C-ONE final drive s;) ;) s;)
m http://www.c-one.co.jp/C-ONEPARTS/final_gear.html (http://www.c-one.co.jp/C-ONEPARTS/final_gear.html) m
As you know, we have a 3.9 final drive...change that to 4.6 and you'll get a massive change in acceleration. LOT more than changing only the 3rd and 4th gear a bit s;) ;) s;)
Quote from: "phat"Euro US
1, 3.166, 3.166
2, 1.904, 1.904
3, 1.310, 1.392 *
4, 0.969, 1.031 *
5, 0.815, 0.815
Final, 3.941, 4.312 *
IMHO the original gear box (C56) final drive is fine. (Any shorter and you *will* need a 6th gear s:P :P s:P ) The Euro box's final drive clearly is too long: it's obvious for example when going up a steep hill in 2nd and you often have to drop into 1st.
Changing just the final drive ratio on a C52 (Euro) will improve performance but not solve the other major problem: the drop in rpm from 2nd to 3rd is massive compared to the original gearbox ratio. No matter how short your final ratio is, the drop will have the same magnitude. Anyone who's driven the '2 hard will know about this long "gap".
From a purely practical viewpoint, I think it's much easier to change the whole gearbox. Changing the final ratio means changing the crown (around the differential) AND the output shaft... (this is no quick job).
Incidently I spoke to a Toyota mechanic who has over 30 years of racing experience, he told me that the "ultra-long 3rd" on sports cars is a "European tradition" designed solely for better fuel economy, but it's a real pain in the arse.
Interesting stuff... Whats the score with the newer 6 speed boxes?
Also, am I correct in thinking that the US/J-spec box wont let the car get up to 60mph in second, so requireing an extra change in a 0-60 sprint? Obviously in Europe the 0-60 is an important marketing tool, but in the US they seem to prefer standing 1/4 mile times as an indicator of performance.
0-60mph: 7.9s (Euro), 7.1s or 7.3s depending on year (J/US).
That's still a big difference, even with the extra gear change.
Anyway, 0-60 (or 0-100 km/h) are a bit naf... a 1/4m (or 400m) is a better measure of performance.
IMO the best way to test is to take the car on a good (twisty) track and time your laps s:wink: :wink: s:wink:
The new 6 speed gearbox has the same ratios as the 5 speed, but with an added 6th gear (see Tem's link to page on Spyderchat.com, on the previous page of this thread s:wink: :wink: s:wink: ).
Looking at all these tables it would appear that the US/J-spec gearbox won't do 60 in second gear, unlike the Euro spec one. Hmm, I understand that in driving terms a close ratio gear box is better at maintaining appropriate engines revs for maximum performance / better acceleration, but won't this extra gear change cancel out any advantage in acceleration for a straight 0-60 time? s:? :? s:?
edit: posted the above at the same time as Phat!
I would be dubious about those 0-60 times - the gearing may not be the only factors affecting these times (driver, conditions, etc...). A fare comparison would be between two cars fitted with the different gearboxes with the same driver, on the same day, same, track, etc, to try and make it a fare test.
Quote from: "phat"0-60mph: 7.9s (Euro), 7.1s or 7.3s depending on year (J/US).
Where did those 7.1s and 7.3s came from? s:shock: :shock: s:shock:
AFAIK, the official Toyota quote for 0-60mph is 7.9s in US as well. And a 2000 model brochure from Japan quotes 7.9s for 0-100kmh.
From Toyota's press release:
"Capable of 0-60 mph performance in slightly over seven seconds"
Actually 0-60 mph was generally quoted as 7.1s for the '00 and '01 models. Some car magazines managed even better times as low as 6.9s. (This is often the case as at least three car magazines in Europe managed to get better times than the official Toyota figures: Evo, TopGear and a Auto Revue.)
Later models became heavier and slightly slower 7.3s (the 2004 model is the worse with a whole load of extra fat member braces).
http://spyderchat.com/comparisons.htm#miata
The only improvement (with time) was for the '03 SMT model (the gear shifting is as good as for the manual version.)
Quote from: "Mr 2"I would be dubious about those 0-60 times - the gearing may not be the only factors affecting these times (driver, conditions, etc...). A fare comparison would be between two cars fitted with the different gearboxes with the same driver, on the same day, same, track, etc, to try and make it a fare test.
But comparing the same car/driver/track is what I'm doing in a much better context than just doing 0 to 60 trials. (Personally, I hate doing these 0 to something trials, almost as much as my clutch hates them... s:wink: :wink: s:wink: ) Anyone used to driving a Euro '2 who tries one with the C56 gear box will be amazed at the difference. (And not just for acceleration timing.)
The figures I quoted are the standard Toyota data.
For info: with the new gear box, I have knocked approx. 0.7s off my 0 to 100 km/h and 1s for the 1/4m. (Did it on the same stretch of road, however not exactly same mass or air density.)
Quote from: "phat"http://spyderchat.com/comparisons.htm#miata
"Data courtesy of Road and Track"
Looks like that time was measured by R&T magazine...?
Like you said, we all know that it's faster than the quotes s;) ;) s;)
Quote from: "GSB"Also, am I correct in thinking that the US/J-spec box wont let the car get up to 60mph in second, so requireing an extra change in a 0-60 sprint?
im sure my j-spec '2 hits the limiter in 2nd gear at 58-59mph, its definately not on the 60 mark anyway. so surely that would mean j-spec have a slower 0-60 time than euro because of the extra chage up.
in 5th gear, every 500rpm equals 10mph e.g:
1500 = 30
2000 = 40
2500 = 50
3000 = 60
4000 = 80
and so on, which would make it a few mph out on that chart thats just been put up. put my speedo is probly out by a few mph anyway
Quote from: "Tomr2"im sure my j-spec '2 hits the limiter in 2nd gear at 58-59mph, its definately not on the 60 mark anyway. so surely that would mean j-spec have a slower 0-60 time than euro because of the extra chage up.
That's just what I was thinking!
Phat; I'm not disputing that there is an improvement with the C56 gearbox with in-gear driving, but I just don't see how there could possibly be any flat out acceleration advantage with the C56 over the C52, as you have to change gear sooner/more often to achieve a certain speed (i.e. 60 mph); let alone beat it by 0.7 second plus! s:shock: :shock: s:shock:
Measuring a performance change by feel may not be very accurate; my mates Peugeot 406 TD feels quicker to 60 than my Rover, because of the characteristics of a TD car, but it is infact it's 2 seconds slower.
Sorry this isn't a dig, I just don't understand how it could be that much quicker... s:? :? s:? s:) :) s:)
No problem. These concepts are sometimes not that easy to grasp. In fact I know quite a few mechanics who still don't understand the difference between torque and power, even less the importance of having the right gear ratios... s:? :? s:?
OK, I'm going to try and illustrate the "practical" way...
If you put your car straight into 2nd gear (or 3rd) and accelerate from standstill up to 60 mph -- you wouldn't even have to change gears. But do you really think you will get a better 0-60 time?... s:? :? s:?
I don't think so (unless you have a magical engine) s:wink: :wink: s:wink:
One of the first things you do when you "prepare" a race (or rally) car for a track or event is to adjust the gear ratios to adjust the amount of acceleration and top end speed (it's often a compromise). (In fact there are many other subtleties...)
Changing gears takes a definite amount of time (in fact it's approximately 0.4s). But if your acceleration is higher and most importantly, if the next ratio keeps your engine rotating in your maximum POWER (not torque) zone, you will maximise acceleration. This explains how I have demolished my 0-60 and 1/4 mile times (as I had expected!)
However you are right about the time lost on gear change. In fact I can reach about 57 mph in under 6.7 seconds! If the engine were a 2ZZ and could rotate over 6800 rpm, the time would be very good because I wouldn't have had to shift up.
But 0-60 times are silly anyway (unless you're a rice boy s:wink: :wink: s:wink: ). What matters here is to have a gear box that's capable of getting the most out of your engine and converting it into maximum torque at the wheels. s:P :P s:P
This graph illustrates pretty well the difference between both gear boxes. (I used the Quaife GB calculator) Quife builds close ratio sequential gear boxes for racing (if anyone is interested) s:wink: :wink: s:wink:
(http://www.spydermagazine.com/files/c52c56.jpg)
Beyond the technology, there's also a "human" issue here:
Most MR2 drivers couldn't care less about the gear ratios on their car. They are happy cruising with it and are not necessarily looking for the maximum performance.
Many bought the '2 because it's a true sportscar (lightweight, agile, powerful, etc.) I'm part of this group.
When I first tried the car I had just sold my 300bhp+ cup tuned 911 Carrera (0-60 in just over 5s) However, I immediately fell in love with the way the '2 handled, it's a brilliant and care free car to drive.
I did a few track days and drove it often hard around great mountain roads etc. I had noticed the wierd gear ratios, but it wasn't until I discovered about the original gearbox (J- and US-spec) that I got pretty pissed off. Because it wasn't a case of something being improved (subsequently) it was the case of a perfectly tuned gear box being replaced in Europe by a badly tuned one...
Of course I could have lived with the Euro box. But $750 got me a brand new C56 in the US. The performance gains are massive and I cannot wait to take it to the "Circuit du Laquais" this Saturday s:twisted: :twisted: s:twisted:
Quote from: "phat"One of the first things you do when you "prepare" a race (or rally) car for a track or event is to adjust the gear ratios to adjust the amount of acceleration and top end speed (it's often a compromise). (In fact there are many other subtleties...)
Thanks for the explanation - I do appreciate what the differences in gearing mean; It just seemed that these figures were a little "optimistic", compared to the change in gearing and needing to change up sooner - however the calculations prove otherwise! As you mentioned before, I wonder why Toyota put the C52 on the Euro spec Roadster (different ratios on 3rd, 4th, 5th and final drive)? Maybe as above they felt it would either better suit our european driving style (?) - a longer 3rd gear as you said.
Quote from: "phat"But 0-60 times are silly anyway (unless you're a rice boy s:wink: :wink: s:wink: ). What matters here is to have a gear box that's capable of getting the most out of your engine and converting it into maximum torque at the wheels. s:P :P s:P
Exactly! Most acceleration is not done from a standing start, so really the most useful gears are probably 2nd, 3rd and 4th and the relationship between them - i.e. closer ratio's being best. s8) 8) s8)
How much did your C56 box cost / where did you get it from? (
EDIT; well you've answered that one now!) Did you do anything else while the box was off - up-rate the clutch / put on a lightened fly wheel? These may be worth doing (particularly the latter) while you got access to them.
Does anyone have any experience of a lightened flywheel on the Roadster, btw?
(Sorry slight thread hijack!) s:) :) s:)
Quote from: "Mr 2"How much did your C56 box cost / where did you get it from? (EDIT; well you've answered that one now!) Did you do anything else while the box was off - up-rate the clutch / put on a lightened fly wheel? These may be worth doing (particularly the latter) while you got access to them.
Does anyone have any experience of a lightened flywheel on the Roadster, btw?
(Sorry slight thread hijack!) s:) :) s:)
I was really tempted by the lightweight flywheel, but wanted to keep costs within reason. I did the gear box swap myself (with the help of the Big Green Book) and asked a friend who has a Toyota garage to help me with the LSD swap. So total cost was about $750 + $200 (shipping from US) + $200 (tools, materials, "pocket money" for the mechanic s:wink: :wink: s:wink: , etc.)
Arnaud (a.k.a. Dieamond) a french MR2 enthusiast has also bought a C56 gearbox in the US. He's going to get it shipped over next month and I believe he's going to buy and fit the lightweight flywheel (instead of swapping the LSD)... He wrote a good article on the difference between the gear boxes
Quote from: "phat"I was really tempted by the lightweight flywheel, but wanted to keep costs within reason. I did the gear box swap myself (with the help of the Big Green Book) and asked a friend who has a Toyota garage to help me with the LSD swap. So total cost was about $750 + $200 (shipping from US) + $200 (tools, materials, "pocket money" for the mechanic s:wink: :wink: s:wink: , etc.)
Arnaud (a.k.a. Dieamond) a french MR2 enthusiast has also bought a C56 gearbox in the US. He's going to get it shipped over next month and I believe he's going to buy and fit the lightweight flywheel (instead of swapping the LSD)... He wrote a good article on the difference between the gear boxes
Interesting - I'll keep an eye out for any news of what it's like! s8) 8) s8)
i beleive sam has a light weight flywheel...
Quote from: "phat"I've compiled a simple table comparing top gear speeds for both transaxles (i.e. 5th gear):
http://www.hanneken.net/MR2/ratios.html
There's something definitely wrong with those numbers. I have a standard UK spec car along with stock wheels/tyres. ~6500rpm in 5th gets you just over 150mph according to GPS (and off the scale of the speedo). I didn't fancy taking it to the rev limiter.
QuoteDoes anyone have any experience of a lightened flywheel on the Roadster, btw?
Yes. Yum!
Quote from: "mph"There's something definitely wrong with those numbers.
Didn't look at it earlier, but you're right, the speeds in that table are too low...
Quote from: "mph"[ I have a standard UK spec car along with stock wheels/tyres. ~6500rpm in 5th gets you just over 150mph according to GPS (and off the scale of the speedo). I didn't fancy taking it to the rev limiter.
Aside from the little matter of a turbo that is s;) ;) s;)
Having seen you dissapear along the autobahn and then seeing the look on your face when we caught up with you, I dont think I would want to find out what speed you can ultimately achieve with the stock ratios either s:? :? s:?
QuoteDoes anyone have any experience of a lightened flywheel on the Roadster, btw?
Ok, to qualify my post a little - there's a lot of labour of getting to the clutch/flywheel. If you're there already and can exclude the labour costs, then it's you're only paying for the material cost of the flywheel - I'd highly recommend it. The stock FW is very heavy (8-9Kg IIRC); my particular one is half the weight. I'll let some clever boffin (GSB?) tell you how much angular inertia saving that equates to, but it's a lot. Between the turbo and the SMT, I can't tell you want acceleration performance you'll get, but if I inverse the increased amount of engine drag I now feel, it's probably quite a lot. The SMT loves the flywheel and blipping the throttle is 'almost' bike-like in performance. I'd look forward to test driving a manual!
how much was your fly wheel mph?
I think I've prevously talked about it in detail - have a look s:wink: :wink: s:wink:
I purchased here - primarily coz I needed a clutch pronto and there wasn't a lot of choice (and Paul had helped me out before..) m http://www.ppeengineering.com/PPEindex.htm (http://www.ppeengineering.com/PPEindex.htm) m
Quote from: "mph"I'll let some clever boffin (GSB?) tell you how much angular inertia saving that equates to, but it's a lot.
Thaks for the vote of confidence! But with out knowing the exact dimensions and distribution of the materail the flywheel is made of, its hard to come up with exact figures... However, the removal of even a small amount of mass from a flywheel can have a big impact, so with 50% of the wieght removed, the engine speed must accelerate very-very quickly... s:shock: :shock: s:shock: .
The upsides of fitting one are well known; power thats not being used to accelerate a bloody great lump of iron on the end of the engine can be used instead for accelerating the car. You're not increasing the engines power, but making better use of the power its got...
The downsides of a lightened flywheel are that you may be able to feel some of the harmonic vibrations that the stock flywheel would otherwise dampen out
(i.e. you may perceive the engine to be running a little "rougher" when in fact its just transmitting vibrations that were always there, but were previously dampened out - If a poorly designed flywheel were to be fitted, there is a chance that these vibrations can cause damage to other parts of the engine. I seem to recall VW engines were susceptible to this, and were cured by fitting a heavier pulley at the front end of the crankshaft.) , Also, due to the reduced mass, theres lots more engine braking. Thats not so bad in theory, but it does mean that if you're a driver of only middling ability, or have a particularly leaden throttle foot, The sudden change in engine power with small throttle movements could very easily catch you out... Say mid bend, a lift off the throttle, and due to greatly enhanced engine braking charachteristics the back end of the car suddenly wants to be in front where all the action is... Owners of very sensitive right feet need only apply!
As for the maths, frankly I cant be bothered as its not easy stuff! But if you really want to go that deeply into it, heres a quote from a Nissan site... s:wink: :wink: s:wink:
QuoteInertia is the property of matter resisting a change in motion. The flywheel resists a change in the speed of rotation of the driveshaft, consuming power during acceleration. A flywheel has mass and inertia. It takes torque, the rotational equivalent of force, to start and stop its turning. The rotational equivalent of mass is the moment of inertia. The more mass an object is, the harder it is to get it to start or stop moving. Moment of inertia depends on the mass of an object and where it is concentrated close to the axis of rotation. Think of the flywheel as a disc. This oversimplifies the properties of a flywheel since a flywheel is not a homogenous mass but thicker in the center than the edges. However, it will make calculations easier to understand and still offers a good estimate. The formula for the moment of inertia, I, is: I=0.5mr^2. Holding r constant since the size of the flywheel is not changing you'll notice mass has a large effect on the moment of inertia. Substitute rotational equivalents for straight-line motion variables in Newton's second law of rotation to determine the amount of force exerted on an object. Use torque for force, moment of inertia for mass, and angular acceleration for acceleration.
If moment of moment of inertia (mass) decreases, less torque is needed to keep the acceleration variable the same. If the same torque is applied, the angular acceleration increases. Now that you've gotten the Physics 101 lecture, let's take this to a more advanced level course. Let's apply this to the 1993 Sentra which weighs about 2,500 pounds and makes about 140 horsepower at 6400 rpm in 3rd gear. Using 3rd gear and final drive ratios, the 3rd gear wheel rpm is 1192 (6400 rpm x 1.286 3rd gear ratio x 4.176 final gear ratio). Calculating for 3rd gear torque and assuming a stock tire radius of 175mm (0.574 feet), this gives a forward rate of acceleration of 0.43 g, or about 13.8 ft/sec^2. Angular acceleration, or how fast the rate of rotation of the flywheel is changing, is 24.1 rad/sec^2 (linear acceleration/tire radius). Multiplying this by 3rd gear ratio and by the final drive ratio, the flywheel is accelerating at 129.4 rads/sec^2. The stock flywheel weighs 18 pounds and is about 0.365 feet in radius, giving a moment of inertia of 0.0434. Flywheel torque is the flywheel angular acceleration times the moment of inertia, or 4.8 ft/lbs and the power consumed by the flywheel is torque times angular velocity, or 5.86 hp. Changing the flywheel weight to a 9 pound lightened flywheel from Unorthodox Racing while holding all other variables constant, the flywheel only consumes 3 hp, freeing up 3 hp in 3rd gear. A lightened flywheel frees up more power in the lower gears since it is harder to begin momentum that to continue it. Solving for 1st and 2nd gears, the lightened flywheel frees up 16 hp in 1st and 6 hp in 2nd. Gains in the higher gears are negligible, 1.7 hp in 4th and 1 hp in 5th.
A car with a heavier stock flywheel will obviously benefit more from a lightened one. The Spec V flywheel weighs in at almost 29 pounds, a heavyweight in the Nissan lineup. Switching to the 12 pound Jim Wolf Technologies flywheel will free up 16 hp in 2nd, 7 hp in 3rd, 4 hp in 4th, 2.5 hp in 5th, and 2 hp in 6th. Amazing, the stock QR flywheel consumes 50 hp more than the lightenend one in 1st gear! It revs happier and has more pickup than a Playboy bunny at a Wall Street bar during happy hour! This engine is already a torque monster so invest in sticky tires to make the most traction of that power.
Since a flywheel absorbs some of the energy generated by the engine during acceleration, lightening the flywheel increases the torque on the driveshaft since less energy is used to accelerate it and more is used to turn the drivewheels. Keep in mind it's not just how much mass is removed from the flywheel but where it is removed. The concentration of mass affects how much resistance the flywheel offers to changing rpm. Rotational inertia increases with the square of the distance of the axis or rotation. Removing weight on the edge of the flywheel is 4 times as good as from the midpoint between the center and the edge. Finally, a flywheel will not show much of a gain in horsepower on a dyno because it doesn't increase fuel or air and can't increase horsepower. Remember, you're not actually improving your car's power, just how quickly it can get to that power. An inertial dyno will show gains by the engine reaching a predetermined rpm sooner with a lightened flywheel.
Quote from: "mph"I purchased here - primarily coz I needed a clutch pronto and there wasn't a lot of choice (and Paul had helped me out before..) m http://www.ppeengineering.com/PPEindex.htm (http://www.ppeengineering.com/PPEindex.htm) m
Assuming you got the RPS, Martin, all I can say is - excellent choice, sir s;) ;) s;)
I have one on t'other car, and quite apart from being an absolute work of art (really, they are..), they're ridiculously light through the main body being billet aluminium - only the contact plates are steel, which are removable and replaceable. Indeed, you can rebuild the whole flywheel to accept a carbon/carbon clutch setup s:) :) s:) (Though that would be overkill on a '2 s:) :) s:) )
FWIW, TRD quotes this for their flywheel:
"Weight: 4,500g (-38%) Moment of inertia: -55%"
I'd been waiting a long time to try out the '2 again on the Circuit du Laquais (one of the great wee circuits we go to regularly as it's not too far from Geneva)...
If you're ever somewhere near Lyon in France, I would recommend a visit...
http://www.circuitdulaquais.com/
(http://www.circuitdulaquais.com/Photos/Circuit2.JPG)
... and I'm totally amazed at the difference the new gear box has made... it's a real pleasure to have better acceleration (155-160 kph at end of straight instead of 145) and the right gear ratio in every situation. In fact I'm now able to go round the circuit with less gear changes than before as 3rd and 4th are now perfect.
Must say the new TRD WayDo struts and Sportivo springs also made a huge difference.
At first the car felt a little bit too "nervous", it was almost like discovering a new car: Turn-in is much more sudden and sensitive (tho' I did get the wheel alignment done), braking also feels more "involving" and the car now stays perfectly horizontal in all situations (unless you flip the car over in one of the sand banks -- something I try to avoid as much as possible s:P :P s:P )
I found that setting the front struts to "medium" (2 or 3) and the rear on "hardest" (4) produced the best results (in dry hot conditions anyway)
Really happy with my lap times (3s less than last April) eventhough my tires were getting a real beating on the overheated tarmac. (My best times were almost always the first 2-3 laps of each series.)
Another member of the French MR2 club joined us in the afternoon. Took him on board for a few laps and he's been completely converted. He's now searching for either a C56 gearbox or a 6sp C60 Celica gear box to fit to his '2... I think he's probably also going to uprate his suspension s:wink: :wink: s:wink:
Yeah, but your 0-60 times rubbish s:twisted: :twisted: s:twisted:
(Only joking)
BTW That track looks amazing, I've been round silverstone south circuit but thats it. I'd really like to get into track days, but with only one car, way too scared i'd trash it (which i most definitly would).
Quote from: "odub"Yeah, but your 0-60 times rubbish s:twisted: :twisted: s:twisted:
I'm crap at 0-60 anyways (hate that fried clutch smell! I prefer the smell of burning rubber s:twisted: :twisted: s:twisted: )
Quote from: "odub"BTW That track looks amazing, I've been round silverstone south circuit but thats it.
I'd love to try one of the "classic" circuits. I think in the UK you're spoilt for choice! I don't know how long that circuit will stay open --you won't believe the problems they have with some of the locals, the "green talibans" and the government -- they are all out to ban track days altogether there and in France in general... s:roll: :roll: s:roll:
Quote from: "odub"I'd really like to get into track days, but with only one car, way too scared i'd trash it (which i most definitly would).
I know the feeling and that's why we generally stick to the "better organised" events that tend to be safer (than some anarchic, overcrowded events) ... at the end of the day, you have to be able to drive home with the same car...
Quote from: "Tem"Quote from: "mph"There's something definitely wrong with those numbers.
Didn't look at it earlier, but you're right, the speeds in that table are too low...
Table bashing? s:P :P s:P (only joking!)
Seriously, there's nothing wrong with the figures... unless Tirerack data is totally rubbish (i would have to go and measure the wheel manually in that case...)
Based on Yoko and Bridgestone S03 tire specs (from tirerack): where average betwen front and rear wheel is 910 revs per mile (1609m): that gives us 1.768m for one wheel revolution.
6500 rpm = 108.3 rps (revolutions per second)
If the wheel was directly attached to the engine, at 6500 rpm we would have 108.3 x 1.768m = 191.5 m/s (a swift 689km/h, or 428mph... but lets get real here, it's a 1.8l 103 kW engine s:wink: :wink: s:wink: )
So here comes the gear and differential (final) ratios: basically the ratios in our gear box reduce the rate of rotation, so for example at 6500 rpm in 5th gear (ration 0.815 and Euro diff ratio of 3.941) 0.815 x 3.941 = 3.212
Use this to divide the engine (input shaft) rpm and you get output rpm at the wheels.
In our example,
6500 rpm at a 1:1 ratio would be 689 km/h or 428mph. With the combined 5th gear and diff ratio (divide by 3.212) we get
214.5 km/h and 133.3mph.
In order to reach 150 mph (using standard size wheels and the Euro transaxle) the engine would need to run at 7300 rpm.
If the rev limiter is set at 6800 rpm, if you reach it in 5th you will be doing 206.4 km/h 128mph (J/US Spec) and 225.8 km/h 140mph (Euro spec).
Quote from: "phat"Based on Yoko and Bridgestone S03 tire specs (from tirerack): where average betwen front and rear wheel is 910 revs per mile (1609m): that gives us 1.768m for one wheel revolution.
Average between front and rear? s:o :o s:o
You lost me there...what average? And why do you need to consider the front wheels at all? You're doing the same mph at same rpm in same gear every time, even if your front wheels would be locked or in the air...
Quote from: "Tem"Quote from: "phat"Based on Yoko and Bridgestone S03 tire specs (from tirerack): where average betwen front and rear wheel is 910 revs per mile (1609m): that gives us 1.768m for one wheel revolution.
Average between front and rear? s:o :o s:o
You lost me there...what average? And why do you need to consider the front wheels at all? You're doing the same mph at same rpm in same gear every time, even if your front wheels would be locked or in the air...
OK this part was a bit confusing s:) :) s:) . I shouldn't have bothered including it as its impact on the speed figures is less than 2% anyway (well within speedometer error margins). But here's the explanation anyway s:wink: :wink: s:wink:
Front tyre is slightly smaller (in circ.) than rear and about the same size as the stock rear Yokos. Taking the average was a way of getting a figure for a partly worn S03.
Interesting though how the data in the table can be so "shocking" s:shock: :shock: s:shock: I don't get it s:? :? s:?
s:) :) s:)
I've done the numbers this morning, slightly differently to you, but come to broadly the same conclusion - something isn't adding up. (see below)
I know my speedo is accurate at 100mph (rolling road) and that GPS also concurs at that speed.
Another approach is this: I reckon that 5th/3000rpm is 66mph - something that can be checked on the road (anyone please verify?). Given gears are linear, this would indicate 143mph is at 6500rpm and 150mph is at 6820rpm. While I admit this doesn't tie in with what I recall the rev counter saying, I certainly do remember 150mph on the GPS (digital display); further, 6820rpm is at least possible. Re-doing the numbers would mean this equates to a combined gearing of 3.12:1. Still doesn't add up, but is a little closer...
Thoughts?
205/50R15
=> wheel = 381mm
=> sidewall = 102.5mm
=> circumference = 1841mm
6500rpm = 108.3rps
150mph = 67.056m/s
67.056/1.841 = 36.42 wheel rps
Combined drive ratio required = 2.97:1
Stated drive ratio from original post = 3.514:1
Here's what I get...
205/50/15 -> circumference of 1.841m
1000rpm at engine is ~1227rpm after 5th gear and ~313rpm after final drive. That's ~577m/min, which is ~34kmh@1000rpm.
So that's ~242kmh@7000rpm, which is ~150mph.
Of course that's VERY dependant on the tyre circumference, which in reality isn't just that. You should measure your tyres to get the real data.
You appear to have a turbo fitted in your '2. Perhaps the gear box has been changed/modified ?
The speedo on any car is often set to indicate 5-10% more "speed" than reality. (This is usually quite cool as it sometimes avoids getting speeding tickets s:P :P s:P )
I use GPS receivers a lot (especially for sailing, etc.). The only thing I can think of that could provide an explanation for an "inaccurate" 150mph reading (if it was inaccurate) is a high GPS DOP (dilution of precision) this can produce "jerks" in speed measurements (and they often show up as an exagerated max. speed -- on boats anyway)
It's a mystery... (twilight zone music) s:lol: :lol: s:lol:
Quote from: "Tem"Here's what I get...
205/50/15 -> circumference of 1.841m
Tem, have you got tractor wheels fitted to your car or what? s:lol: :lol: s:lol:
Here's are the official specifications for the S03 tires:
http://www.bridgestonetire.com/dpp/sizespecs.asp?passproductid=227
On the 7th row (205/50/15) you find 560 RPK (revolutions per km) (= 902 RPM)...
So: 1000m/560 =
1.7857m For the (bigger) yoko A043s: we have 1000m/558=
1.792mSo once again, I restate that the data in the table is correct s:roll: :roll: s:roll: (sorry)
Furthermore, with a stock 1ZZ engine and a Euro gearbox you will not get anywhere near the rev limiter in 5th gear (unless pulled along by a GT3, or going down a steep hill or something s:wink: :wink: s:wink: ) Even if you could, at 6800 rpm you are still "only" doing around
226 km/h (140mph).
However, I am sure that your speedo will be indicating much more (240km/h or 150mph) would be perfectly reasonable.If you add a turbo, I am also sure you *will* be able to go all the way up to the redline even with the longer euro gear box. If you tweaked the engine ECU to push back the rev limiter (to say 7000rpm) you would reach maybe 145 mph (over 150 mph on the speedo)...
But anyway, what are we talking about? s:? :? s:? Where would you drive at 150 mph? And even if you could, what's the point, you could't hear your car stereo anymore! s:lol: :lol: s:lol:
Quote from: "phat"Tem, have you got tractor wheels fitted to your car or what? s:lol: :lol: s:lol:
That's the stock wheel size s;) ;) s;) But like I said:
"Of course that's VERY dependant on the tyre circumference, which in reality isn't just that. You should measure your tyres to get the real data."
QuoteFurthermore, with a stock 1ZZ engine and a Euro gearbox you will not get anywhere near the rev limiter in 5th gear
I know and I'm not saying I could, just saying I think your table is wrong s;) ;) s;) My limiter is at 7600rpm anyway s;) ;) s;)
Quoteyou could't hear your car stereo anymore! s:lol: :lol: s:lol:
I hope not, cause mine's in the garage s:lol: :lol: s:lol:
Quote from: "phat"Here are the reference numbers and approx. prices:
Final ratio: 33402-12041 $93.51
3rd ratio: 33034-12130 $80.24
4th ratio: 33035-20170 $80.25
Does this mean that two new gears are only $160? s:shock: :shock: s:shock:
(seems I might have to open my gearbox, so might as well see if I can get those in)
and a lot of money to fit em Tem s:? :? s:? good luck though, unless you feel capable of doing this yourself and have a press
Quote from: "kanujunkie"and a lot of money to fit em Tem s:? :? s:? good luck though, unless you feel capable of doing this yourself and have a press
Yeah, I was thinking of trying it myself. I do have a press.
Quote from: "Tem"Quote from: "kanujunkie"and a lot of money to fit em Tem s:? :? s:? good luck though, unless you feel capable of doing this yourself and have a press
Yeah, I was thinking of trying it myself. I do have a press.
lucky bastard s:wink: :wink: s:wink:
you must have a nice workshop then
Quote from: "kanujunkie"lucky b*****d s:wink: :wink: s:wink:
you must have a nice workshop then
It's really nothing special s:lol: :lol: s:lol:
12ton press is only like 100 euros anyway...it's pretty much just a large hydraulic bottle jack with some steel around it.
Quote from: "Tem"12ton press is only like 100 euros anyway...it's pretty much just a large hydraulic bottle jack with some steel around it.
I think we need to start importing more stuff from Finland s;) ;) s;) The cheapest (10ton bench press (http://www.machinemart.co.uk/product.asp?p=020410030)) is over twice that price in this country..
Quote from: "aaronjb"Quote from: "Tem"12ton press is only like 100 euros anyway...it's pretty much just a large hydraulic bottle jack with some steel around it.
I think we need to start importing more stuff from Finland s;) ;) s;) The cheapest (10ton bench press (http://www.machinemart.co.uk/product.asp?p=020410030)) is over twice that price in this country..
s:shock: :shock: s:shock:
Then again, mine's more basic...doesn't have fancy lines like that s:lol: :lol: s:lol:
It's not this one, but looks similar:
m http://www.biltema.fi/osteri/osteri.cgi ... yhmaid=143 (http://www.biltema.fi/osteri/osteri.cgi?sivu=skriptisivut/index_kauppa.htm&linkki=15834.htm&tuote=15834&ryhmaid=143) m
Quote from: "phat"Here are the reference numbers and approx. prices:
Final ratio: 33402-12041 $93.51
3rd ratio: 33034-12130 $80.24
4th ratio: 33035-20170 $80.25
Where did you get these prices...? Local Toyota quotes over $200 for each s:? :? s:?