120mph Restriction

Anonymous · March 14, 2004, 23:21

so why do some japanese cars top out at 112mph and some at 120? my 2' a j-spec so will probably only go to 120mph, but my speedo goes all the way to 180??? s:? :? s:?

scottee · March 15, 2004, 09:06

Tom, I think the 180 was supposed to be for kph.

I just checked to see if mine was labeled mph but maybe was in kph, I tailed a few cars into some 30mph and 50mph Gatso's and the speeds seem right, so how come mine is cutting up at 115-120 mph on uh.... my private runway s:)

s:) wierd s:(

s:(

Anonymous · March 15, 2004, 09:27

Anyone know the correct part number for the SLD for a US spec 2?

Tem · March 15, 2004, 10:57

AFAIK, the limiter is at 180kmh in most japanese vehicles, that's about 112mph real speed. It might easily be 120mph on the speedo though. And if you change your wheels to non-stock size, the limiter has no idea about real speed anymore.

juansolo · March 15, 2004, 13:15

Could've sworn that Jap cars were limited to 118... If 112 is right then my speedo overreads by a hell of a lot!

FWIW, at an indicated 125 there's bugger all left in the car anyhow. Hardly worth the bother IMO.

aaronjb · March 15, 2004, 13:21

Quote from: "juansolo"Could've sworn that Jap cars were limited to 118... If 112 is right then my speedo overreads by a hell of a lot!

Definitely 112Mph.. And overreading by 5-6mph at that speed sounds about right - mine overreads (vs. my GPS) by 5mph across the scale, as do most peoples I believe..

Humble Jim · March 15, 2004, 13:52

Quote from: "Liz"<DISCLAIMER s:) s:) >

And the club does not condone going at these speeds!

Absolutely right. There's a time and a place and 120mph on the M4 or any other public UK road is not it...really it isn't. s:? :? s:?

Anonymous · March 15, 2004, 14:37

ive heard the manufactures put them out by +5/10% on purpose for some legal reason so you cant sue them?

Mine has a little sticker over the top of the KPH text which i asssume all j-pec vehicles are

Anonymous · March 15, 2004, 14:57

I have a j-spec 2 and know that the limiter was removed when converting the car from kph to mph!

Tem · March 15, 2004, 15:11

Quote from: "Tomr2"ive heard the manufactures put them out by +5/10% on purpose for some legal reason so you cant sue them?

I don't think you can sue them for that, we're not in US! s:lol: :lol: s:lol:

But yes, the speedo has to show the real speed or more. Always. It cannot ever show less than real speed. That's why most (if not all) manufacturers make it show a bit more on purpose.

Anonymous · March 15, 2004, 19:02

The J-Spec MR2's are limited to 114MPH. Mine was, i checked to see f it had been removed s:wink: :wink: s:wink: and got 131 MPH! The limit was the fact the revometer hit the red line in 5th gear (i dont have a 6th gear).

FYI i have a performance exhaust and filter but dotn think it would allow 10mph increased top speed over the unmodified, especially if that would require 38more bhp s:shock: :shock: s:shock:
I would say conditions were favourable s:wink: :wink: s:wink:

You can get the limiter removed, or be thankful it is preventing you from doing something dumb s:? :? s:?

Anonymous · March 15, 2004, 23:04

how often does anyone go over 100mph anyway, ok maybe in germany but then the car is doing silly revs then and really guzzling your fuel. I dont think (in this country anyway) your insurance covers you for over 100mph

mph · March 15, 2004, 23:44

Certain policies do when it's an officially organised track or airfield day s:)

s:)

mph · March 15, 2004, 23:46

Quote from: "vibratingsky"The J-Spec MR2's are limited to 114MPH. Mine was, i checked to see f it had been removed s:wink: :wink: s:wink: and got 131 MPH! The limit was the fact the revometer hit the red line in 5th gear (i dont have a 6th gear).

Do I take it the j-spec gearbox is the same as the US then and only Europe has the longer gears? Anyone?

Anonymous · March 15, 2004, 23:53

only got my 2 at the weekend (is a j-spec) and was redlining it a bit today s:twisted: :twisted: s:twisted: and noticed that 2nd gear only took it to 59mph - that means i have to change up to third to get my 0-60 time which stinks.

Are the ratios longer for uk model?

Anonymous · March 16, 2004, 03:22

Think your right Martin. It helps for acceleration, but sucks at top end...... Which would you rather have?

Think a test for the library is needed, i'm willing to test mine for results.

Anonymous · March 16, 2004, 23:30

Quote from: "adz648"anyone got any what toyota say the uk stock 2 with do top end

i think I'm going to have problems blaming mr t

how much does a rolling road test cost as i might have to resort to this and send them the bill if the car is faulty

I have a 2003 with a tte exhaust. It went to 220kh on 6 gear. After gutting the pre-cats, it goes to 235k/h.

To see if you have a restrictor, just try the car full throttle in an inclined highway, going down, obviously s:wink: :wink: s:wink:

Peter Laborne · March 17, 2004, 00:08

Please note - MR2 ROC does not advocate the breaking of speed limits. If you need to exceed the speed limit then we advise you do this on a rolling road, at a track, at an airfield, on private land (where you have the owners permission), or on roads with no speed limits. In addition, MR2 ROC does not advocate the 'testing' of vehicles on public roads.

markiii · March 17, 2004, 00:13

Quote from: "pp"
Quote from: "adz648"anyone got any what toyota say the uk stock 2 with do top end

i think I'm going to have problems blaming mr t

how much does a rolling road test cost as i might have to resort to this and send them the bill if the car is faulty

I have a 2003 with a tte exhaust. It went to 220kh on 6 gear. After gutting the pre-cats, it goes to 235k/h.

To see if you have a restrictor, just try the car full throttle in an inclined highway, going down, obviously s:wink: :wink: s:wink:

you can add as mucg power as you like. ultimately it's gearing thats going to limit you.

Anonymous · March 17, 2004, 10:56

Quote from: "markiii"
Quote from: "pp"
Quote from: "adz648"anyone got any what toyota say the uk stock 2 with do top end

i think I'm going to have problems blaming mr t

how much does a rolling road test cost as i might have to resort to this and send them the bill if the car is faulty

I have a 2003 with a tte exhaust. It went to 220kh on 6 gear. After gutting the pre-cats, it goes to 235k/h.

To see if you have a restrictor, just try the car full throttle in an inclined highway, going down, obviously s:wink: :wink: s:wink:

you can add as mucg power as you like. ultimately it's gearing thats going to limit you.

Sure, but with the 6sp gearbox you reach 200kh at 5000 rpm, so, if you could reach the redline in 6gear (more power needed) you could reach 260?, 270?, and if you have the power and want to go faster, you just have to put 17' weels and only then you have to change ratios, but I think that the speed the car can reach without toutching the gearbox is enough for me s:wink: :wink: s:wink:

juansolo · March 17, 2004, 15:45

Quote from: "markiii"you can add as mucg power as you like. ultimately it's gearing thats going to limit you.

Biggest factors are gearing, aerodynamics and power.

It's easiest example I can think of to demonstrate this is a Caterfield as they're an aerodynamic brick (designed in the 1950's remember).

What makes a Caterfield quick is it's incredible light wieght allowing you to run fairly mundane engines and go like the clappers. However a 100bhp Caterham, thought it'll get you to 100 quite sharpish, will struggle to get much higher. The first thing to do to increase top end is to remove the windscreen as this acts like a air brake and gives you around another 10 mph top speed.

But you still need a massive increase in power to bludgeon the brick through the air and get it to nigh on 150mph. Think a 130bhp hike to 230bhp in the R500 for an extra 40mph...

Gearing, as Martin says is another limiting factor. My Westfield runs a straight cut Quaife gearbox with an incredibly tall first and all the other gears all stacked very closely together. Basically this means that the top speed in 5th is limited by the redline at around 125mph. This however matches nicely with the power of the engine and the configuration of the car. Which is a nice balance but it still tops out at some circuits which can be a bit frustrating.

juansolo · March 17, 2004, 17:08

In fact, if you know the gear and final drive ratios I know of a program that will give you the top speeds in each gear and things like pick up rpm of the next gear. We used it to work out the ratio's we wanted in the gearbox of one of our cars. Bloody useful program.

Peter Laborne · March 17, 2004, 18:59

For the 2000 (Rev1) Roadster:

Gear ratio

1st = 3.166
2nd = 1.904
3rd = 1.310
4th = 0.969
5th = 0.815
Reverse = 3.250
Differential gear ratio (final) 3.941

Max permissable speed (according to Toyota)

1st = 36mph
2nd = 60mph
3rd = 87mph
4th = 118mph
5th = 129mph

juansolo · March 17, 2004, 19:16

Trying to find the bloody program again... grr!

Edit - S'alright, I found a different one.

Can't C&P the results though or view source s:(

s:(

The bit we're interested in though is this:

mph @ 6500rpm for a pre '03 Mr2 on standard tyres
1st - 35.6 mph
2nd - 59.1 mph
3rd - 85.9 mph
4th - 116.2 mph
5th - 138.1 mph

rev - 34.6 mph

Rev drop on shift
1st-2nd - 2591 rpm
2nd-3rd - 2028 rpm
3rd-4th - 1692 rpm
4th-5th - 1033 rpm

Anonymous · March 17, 2004, 20:30

HOWEVER! the rev limit on the MR2 is 6750rpm, so 2nd gear should get you to 60mph s:D

s:D
This is interesting though, keep it coming!
FYI my 131mph was at 6500rpm but the incline was downward a little, although this must be approaching the 5-gear versions highests speeds, I'd guess 135mph? even with if i had 200bhp (I guess I have 150bhp/ton with my mods).

If you gut the cats, will this invalidate my insurance? shurely this equates to a 5% power increase (serious business!)