Thought I'd start a new thread so folk can find the info easier. Thread
@Petrus started with the detailed info below.
https://www.mr2roc.org/index.php?topic=74205.0
So fitted the refurbished Prius XW20 calipers last night with new discs and Dixcel race pads.
(https://i.postimg.cc/gjHhdP6z/prius.jpg)
I only got around to bedding in the new discs and pads, so not full blown stamping on them but already you can feel its an upgrade over the MR2 set up. No substantial difference in pedal feel, maybe a tad firmer and only approx 5mm of extra travel. I only really got up to 80% braking force and the do bite hard! I could easily get the ABS to trigger which is exactly what I was hoping for because with the MR2 set-up it was a struggle to fire the ABS on sticky tyres.
Anyway the acid test will be my next track day at Anglesey In August.
More to follow...
Glad you like the set. Happy to have been of help.
You will like the change even more on track.
The 10% larger force up front will allow you to use the racing pads better.
Also 1.2 kg (or so) per wheel is quite a lot. Not changing the car of course but it does all count.
With ´stock´ pads the difference passes unnoticed for most even though the weight loss is of greater effect on the real world road surfaces.
I kept all the same but for the calipers so the comparison is pure before & after.
I am véry happy with this dirt cheap and cheerfully simple brake upgrade!
Do I need to look for specific calipers or all xw20 are with the same ones?
All I could find locally is 1.5 hybrid.
Quote from: Nvy on July 12, 2023, 10:52Do I need to look for specific calipers or all xw20 are with the same ones?
All I could find locally is 1.5 hybrid.
That´s the one.
Part numbers in this thread would be useful.
Not that there are any other ones ::) but here we go:
Front right and left calipers on 2004-2009 Prius. Part numbers 4775047050 and 4773047050 or 4775047020 , 4773047020
Part numbers:
Drivers (right) Toyota OE - 4773047050 or 4773047020
https://www.autodoc.co.uk/kamoka/19171257
Passengers (left) Toyota OE - 4775047020 or 4775047050
https://www.autodoc.co.uk/kamoka/19171256
At the breakers just ask for Prius 2 (or 20).
Over here they are as a set half price of óne for a ZZW30.
Bottom line: Have even móre fun 8)
p.s. They also fit the AE chassis p.e. AE86. This is where the mod. crossed over to the ZZW30 from.
This is great news for this platform no matter what kind of driving you do. Anything to decrease the unsprung weight for better front damping control to give you an increase in comfort.
The best part is there is much higher availability of this caliper so you can get almost like new ones then having to depend on refurbished parts that have questionable quality because they have to machined.
It would be nice if there was a rear option from another Toyota vehicle. I think with a modification to the parking brake lever it could work.
Quote from: Petrus on July 12, 2023, 12:44Not that there are any other ones ::) but here we go:
Front right and left calipers on 2004-2009 Prius. Part numbers 4775047050 and 4773047050 or 4775047020 , 4773047020
There are plenty of other aftermarket part numbers, actually. Not everyone uses OEM.
Quote from: Alex Knight on July 12, 2023, 16:33There are plenty of other aftermarket part numbers, actually. Not everyone uses OEM.
Thank you.
Quote from: Nvy on July 12, 2023, 10:52Do I need to look for specific calipers or all xw20 are with the same ones?
All I could find locally is 1.5 hybrid.
Those. The gen2 prius, all 1.5
Quote from: Ardent on July 13, 2023, 17:01Those. The gen2 prius, all 1.5
... and all hybrid, which is for mé a 8) extra. Completely subjective of course; much like the perceived added value of a brand for some. With the difference that it is an entirely personal pleasure as nobody can see it, which Í think extra fun. And that all for peanuts ;)
A bit like adding lightness; a gift that keeps on giving.
Oh wait, it ís adding lightness.
Ahhh, la vida es bella :))
Dipped into the calipers for the ct200h which will no doubt match those on the prius gen 3 1.8 the pistons are slightly larger again.
Quote from: Ardent on July 13, 2023, 22:39the pistons are slightly bigger again.
As I calculated elsewhere, the effect of slightly larger front pistons is waywáy less that the increase in piston surface.
There ís another (obvious) aspect to the aluminium Prius2 calipers btw and I was crossing my fingers about it for the RPF1s but even with those the clearance works out so all systems go!
As such next on my agenda (for the brakes) is the rear.
Thought this was quite funny to find when testing out the newly indexed search:
https://www.mr2roc.org/index.php?topic=25076.msg310567#msg310567
2009!
Edit: hopefully nobody is surprised the links in there are dead :)
Quote from: shnazzle on July 14, 2023, 08:45Thought this was quite funny to find when testing out the newly indexed search:
https://www.mr2roc.org/index.php?topic=25076.msg310567#msg310567
2009!
Brilliant find!
Véry funny indeed!!
Next is 2023 when a forrinnah actually tríes it prompted by a bloke from Russia :))
Thanks for sharing that
@shnazzle .
So Anglesey done and I can now reflect. Brilliant upgrade over the cast iron OE calipers. Not a hint of fade all day and a really consistent pedal, plus they really do bite harder. I've used some serious pads in the past e.g XP10, XP12 RP2 etc and found them all lacking due to the OE calipers overheating, the prius ones no such issues.
Thanks for the feedback.
Totally logical/predictable as aluminium dissipated heat better and the Prius is heavier car.
It was my experience too here barelling down the mountains with tarmac temps of 60+ centigrades.
Still best have it confirmed from the track too.
So these fit onto the MR2 carriers and use MR2 pads? No other mods needed?
Quote from: Iain on September 13, 2023, 18:33So these fit onto the MR2 carriers and use MR2 pads? No other mods needed?
Yes and yes.
No.
Have them for over 2 months now and al thumbs up.
Thanks.
Seems a very worthwhile change especially for track use. And pretty cheap for what you're getting.
Quote from: Iain on September 13, 2023, 20:54Thanks.
Seems a very worthwhile change especially for track use. And pretty cheap for what you're getting.
Better brakes save lives. More applicable on the public road tha on the track.
I'm still looking on the bay of E but nothing really coming up. Mildly surprised and slightly disappointed.
Just joined (first post!) to say thanks for posting this, I have just ordered from autodoc. I love this kind of parts bin upgrade!
I bought a 1MZ-FE swapped MR2 (by Woodsport) earlier in the year, the front brakes are a slightly sticky and it pulls to the left, so this seems like a better option than refurbing the old ones.
Quote from: __CA__ on October 4, 2023, 15:05Just joined (first post!) to say thanks for posting this, I have just ordered from autodoc. I love this kind of parts bin upgrade!
I bought a 1MZ-FE swapped MR2 (by Woodsport) earlier in the year, the front brakes are a slightly sticky and it pulls to the left, so this seems like a better option than refurbing the old ones.
Check (all) your suspension bolts. I had pulling to the left twice and both times it was down to suspension bolts needing torquing up.
Edit: Welcome!!
Interesting, thank you... the suspension was all re-bushed about a year (but probably only 500 miles!) ago.
Could be completely unrelated, but pay say attention to subframe etc if recent work done.
This is a great find. If you buy pattern parts, how do you know if they're also aluminium?
Quote from: bluesmoke on October 9, 2023, 18:40This is a great find. If you buy pattern parts, how do you know if they're also aluminium?
High strength parts are typically steel, containing iron and therefore attracted to a magnet. These calipers are cast from an aluminium alloy, such an alloy does not contain iron and won't be attracted to a magnet.
Quote from: MrChris on October 4, 2023, 17:38Check (all) your suspension bolts. I had pulling to the left twice and both times it was down to suspension bolts needing torquing up.
Edit: Welcome!!
_CA_
I recall a report on here that the top shock absorber nut/s were found to have come loose. This was attributed to the flats on the top of the shock rod not having been engaged in the slot in the top mount. The top nut/s somehow had been tightened , perhaps with a rattle gun, but then working loose and causing noticeable effect.
Thanks for that tip as well, I'll take a look.
The calipers arrived from Autodoc today... WOW they're light! Now I just need to not do my usual and leave them in a box for 6 months... ;D
Quote from: __CA__ on October 9, 2023, 21:40The calipers arrived from Autodoc today... WOW they're light!
and if you compare with the OEM one when you have it off.... :o :o
And they even stop júst that bit better as a bonus with potential fading eliminated.
Quote from: __CA__ on October 9, 2023, 21:40Thanks for that tip as well, I'll take a look.
The calipers arrived from Autodoc today... WOW they're light! Now I just need to not do my usual and leave them in a box for 6 months... ;D
Quite interested in what you ordered etc, and arrived. Costs if not to personal.
Been looking on ebay, but not having much luck.
Quote from: Ardent on October 10, 2023, 17:06Quite interested in what you ordered etc, and arrived. Costs if not to personal.
Been looking on ebay, but not having much luck.
See post #6.
Quote from: Alex Knight on October 10, 2023, 21:46See post #6.
Thank you.
Strange ole world. The Right one is £61 the left £48. I thought non handed so could but 2x left. That said as someone else pointed out having the bleed nipple at the top makes sense.
By the time phaffed about with ebay, cleaning up, rar rar rar, might just as well pull the trigger on autodoc and be done with it.
For additional info on these they are actually handed, they have L & R on each caliper but you fit them with the letter facing up, this should orientate the bleed nipple at the top. Also from Autodoc they come with the OE Phenolic (plastic) pistons. These will be absolutely fine for road, but for track I changed them out for steel pistons as I dont want to take a risk of them melting.
as I observed earlier I simply assumed that the L and R would be in line with bleed nipples being up. Although common sense and thus in case of Japanese cars the way to go, still better to first lóók and thínk ::)
About the pistons imo using steel ones for racing has two sides. For one it makes sense because of the heat involved but on the other hand they will expand considerably more. Also the calipers being aluminium they will dissipate heat at about double the rate the steel ones do ánd the pistons are ´liquid cooled´.
It being brakes and me being old school, I instinctively thínk steel being the safer bet on track but would try investigate a bit deeper as it very well may be reverse.
Anyway, on the road they are simply a literally cool mod. giving better braking. Again; it does not change the car; just makes it a little bit more enjoyable still. Imo ;)
A3VT!
Has anyone looked at the 2003-9 Prius front knuckles? They are aluminium but otherwise look very like the MR2 ones.
A bit out of left field, but I take it this wouldn't work on an AW11? Don't even know if the stock AW11 calipers are heavy in the first place but still.
Quote from: Snelbaard on November 24, 2023, 14:26A bit out of left field, but I take it this wouldn't work on an AW11? Don't even know if the stock AW11 calipers are heavy in the first place but still.
Stock is heavy iron and I know it is a mod on the AW11 too, not sure if it is without any modification.
Quote from: Petrus on November 24, 2023, 15:01Stock is heavy iron and I know it is a mod on the AW11 too, not sure if it is without any modification.
Well, I don't mind getting my hands dirty a little bit :) And from your experiences, it seems like a very worthwhile upgrade so I'll certainly look into it more!
Quote from: Snelbaard on November 24, 2023, 15:27Well, I don't mind getting my hands dirty a little bit :) And from your experiences, it seems like a very worthwhile upgrade so I'll certainly look into it more!
Get a set from the breakers; they are cheap enough and you can always sell them on if you don´t like them. I sure do lóve them.
Still surprised at how few there seem to be over here. Bay of e etc
Quote from: Ardent on November 24, 2023, 16:16Still surprised at how few there seem to be over here. Bay of e etc
Surprising indeed; over here they are thirteen a dozen.
The ZZW30 community is not jumping on it with gusto so that cannot be it ;)
In the States (spyderchat) there are so far none :o whereas it is an easy, cheap, serious improvement.
I accidentally ordered two right handed calipers from AUTODOC (all sorted now, I possess a matching pair). If anyone is interested in a discounted LH prius caliper then email me
@ leomarch666
@gmail.com and we can arrange something
Quote from: Slowpoke on November 27, 2023, 15:06I accidentally ordered two right handed calipers from AUTODOC (all sorted now, I possess a matching pair). If anyone is interested in a discounted LH prius caliper then email me leomarch666gmail.com and we can arrange something
@Ardent ?
Will our standard discs and pads drop straight into these then or is that wishful thinking?
Quote from: Hammond on November 27, 2023, 21:04Will our standard discs and pads drop straight into these then or is that wishful thinking?
I would hope so as I've got some EBC discs and pads for the mr2 to go on with the prius calipers. If they're a straight swap I don't see why OEM sized parts wouldn't fit.
Quote from: Hammond on November 27, 2023, 21:04Will our standard discs and pads drop straight into these
yes.
It´s a straight swap. No other mods needed.
Quote from: Petrus on November 27, 2023, 21:59yes.
It´s a straight swap. No other mods needed.
Have you fitted these all four corners then? 8)
Quote from: Hammond on November 28, 2023, 17:26Have you fitted these all four corners then? 8)
It's only for the front.
Quote from: JB21 on October 11, 2023, 07:44For additional info on these they are actually handed, they have L & R on each caliper but you fit them with the letter facing up, this should orientate the bleed nipple at the top. Also from Autodoc they come with the OE Phenolic (plastic) pistons. These will be absolutely fine for road, but for track I changed them out for steel pistons as I dont want to take a risk of them melting.
What's the part code for the steel pistons ? I'm tracking my car too and don't want a melty.
I've ordered some steel pistons code 47731-47010.
The phenolic/bakelite pistons that came out were 54mm od and 46mm tall.
I did some testing with the phenolic - it's an interesting material.
TL/DR:
@JB21 is spot on we shouldn't run these with phenolic pistons on track.
Longform:
It's an amazingly strong material and exceptionally heat resistant for a plastic - and an excellent stock piston / for a non-sporty use brake system. It's almost closer to a ceramic, to me.
I baked the phenolic at around 220c to heatsoak it. It didn't smell too bad. Didn't melt, either. A regular commute driven prius will probably never reach these temps either. Hence.. it's a good solution for this.
But under a heatgun it got to 300c and it was literally starts making a crackling sound [bacon frying] - remember your pads will get very hot on track and as the heatsoak in the caliper builds up you will get well over 200c. 10 laps maybe ok, but 30 could get it to this point.
Interestingly under the heatgun I could smell laphroig - the phenols of a nice peated whisky XD
See https://www.sumibe.co.jp/english/product/hpp/molding-compound/phenolic/index.html
"This makes it look like it loses at least 10% of its strength by 200C"
Remember that on track you will trying to get heat into the brakes to get the friction material up to temp. If you look at a track pad friction graph you will see they only get better as the temp gets over 200c.
The longer you stay out doing laps and harder you drive, the more likely these phenolics are to fail on you. We typically see the pads fade or the fluid boil first as a factor there. Caliper piston melting or cracking isn't really a normal thing.
As a final move I took the blowtorch and set it on fire - surface cracks appeared on the outside of the piston within seconds. Also the smell went from whisky to burning pvc. I could you could call this simulating putting the pads on fire. I've got (poorly edited) video of this if you want to see.
Tests suggested by
@moca2cv aka John
Thanks for sharing that factual test!
Quote from: atlex on December 18, 2023, 09:47I baked the phenolic at around 220c to heatsoak it. It didn't smell too bad. Didn't melt, either. A regular commute driven prius will probably never reach these temps either. Hence.. it's a good solution for this.
Ergo even better for a 300 kg lighter ZZW30 also when spiritedly driven on the public road.
Ergo
2 for my 150 kg lighter still itsiebitsie. Barrelling down a smoldering southern slope in summer might look iffy at first idea, but the speeds are very low so the energy dissipated relatively moderate.
The lower unsprung weight of Enkeis & Prius calipers does make a notable difference in better road holding i.e. shorter stopping. Imo way more important on the public road than on track. The traffic density where and when I drive eliminates (knocking wood) the risk of being clobbered from behind by a less short stopping modern übersized car.
Quote from: atlex on December 18, 2023, 09:47An excellent and informative post by @atlex about changing out the pistons for steel ones that I was keen to find out the answer to.
@atlex what an excellent and informative post, I was keen to find out the answer to your original question and you went ahead and did a science experiment!
Also wanted to add that the phenolic pistons were amazingly heavy - I guess all that density goes towards maintaining strength under potential mild heatsoak - they were around 170 Grams each - I doubt the steel pistons will be much heavier.
Also consider what a track pad gets peak friction at - it's more like 500c on a trackday pad and it will be higher on a race/competition pad.
Having given up with ebay I might as well just pull the autodoc trigger
Quote from: Ardent on December 18, 2023, 21:29Having given up with ebay I might as well just pull the autodoc trigger
When I used Autodoc I was somewhat uncertain about what I wanted/ what was offered and so took up their "return" deal. Did not seem overly costly. I did send some parts back , rubber front suspension bushes that I decided against and returned to Autodoc , without much trouble, and got SuperPro from TCB.
It was not an overnight service from Autodoc but within their stated time frame.
Would I use them again, yes.
@Joesson thanks for that. I have been very reluctant to buy from them. But the time has come to grasp the nettle.
I always have this image of a good price then being spanked by HRMC for import or whatever duties. But I am not hearing that from those that have gone before. (or they have chosen not share that bit)
Great work
@atlex! I'll be interested to know the weight of the steel pistons; if it's within a few grams of the phenolics, seems like the upgrade is a no-brainer?
Quote from: Ardent on December 18, 2023, 21:29Having given up with ebay I might as well just pull the autodoc trigger
What's wrong with an actual motor factor?
Quote from: inigopete on December 18, 2023, 23:31Great work @atlex! I'll be interested to know the weight of the steel pistons; if it's within a few grams of the phenolics, seems like the upgrade is a no-brainer?
In the first thread on this (search
Prius calipers is easy enough), JB weighed the steel pistons to make the caliper 200 grams heavier.
For road it makes no sense whatsoever, for (serious) track use it is a must.
A3VT!
Quote from: Ardent on December 18, 2023, 22:58@Joesson thanks for that. I have been very reluctant to buy from them. But the time has come to grasp the nettle.
I always have this image of a good price then being spanked by HRMC for import or whatever duties. But I am not hearing that from those that have gone before. (or they have chosen not share that bit)
No other bits to share J and sufficient time has passed that I can be very reasonably confident that I won't be having a knock on the door!
I also returned items and that was relatively painless, only having to print out a label and take the parcel to the Post Office.
I weight the phenolic vs steel and the steel I got are 466g, the phenolic 165g, call it 300g more?
the Prius calipers with the steel pistons are 1560g
I've yet to weight the stock calipers but others report those are 2500g, if that's true, this is still very much worth it.
Quote from: atlex on December 21, 2023, 21:49I've yet to weight the stock calipers but others report those are 2500g, if that's true, this is still very much worth it.
Go figure with the phenolics for the road. I réaly enjoy them.
Being aluminium the calipers dissipate more heat there too It´s all win. And that for a cheap straight swap!
Quote from: Petrus on December 21, 2023, 23:07Go figure with the phenolics for the road. I réaly enjoy them.
Being aluminium the calipers dissipate more heat there too It´s all win. And that for a cheap straight swap!
All well and good but this "find" came after my brake overhaul when I replaced the rear calipers and renovated the fronts.
I did repaint the fronts with aluminium paint though, so maybe that will help!
Quote from: Joesson on December 22, 2023, 10:07All well and good but this "find" came after my brake overhaul when I replaced the rear calipers and renovated the fronts.
I did repaint the fronts with aluminium paint though, so maybe that will help!
As with all things shared by anyone, it is take it or leave it
@Joesson.
As with all things shared, it may very well be of hardly any or even no use to many others.
In general progressing insight is often a pita.
In the case of these calipers they probably came too late for the ZZW30 production too.
Does not change the factual benefits over the OEM ones ;)
Now the question is.. what can be done for the rear ? XD
Is there some aygo or camry rear caliper drops a few grams ?
Quote from: atlex on December 24, 2023, 22:47Now the question is.. what can be done for the rear ? XD
Is there some aygo or camry rear caliper drops a few grams ?
Good question, but there aren't any other mid engined Toyotas to choose from I suspect.
To my unenlightened mind the issue is the handbrake not the hydraulic foot brakes
Quote from: atlex on December 18, 2023, 09:47I've ordered some steel pistons code 47731-47010.
The phenolic/bakelite pistons that came out were 54mm od and 46mm tall.
I did some testing with the phenolic - it's an interesting material.
TL/DR: @JB21 is spot on we shouldn't run these with phenolic pistons on track.
Longform:
It's an amazingly strong material and exceptionally heat resistant for a plastic - and an excellent stock piston / for a non-sporty use brake system. It's almost closer to a ceramic, to me.
I baked the phenolic at around 220c to heatsoak it. It didn't smell too bad. Didn't melt, either. A regular commute driven prius will probably never reach these temps either. Hence.. it's a good solution for this.
But under a heatgun it got to 300c and it was literally starts making a crackling sound [bacon frying] - remember your pads will get very hot on track and as the heatsoak in the caliper builds up you will get well over 200c. 10 laps maybe ok, but 30 could get it to this point.
Interestingly under the heatgun I could smell laphroig - the phenols of a nice peated whisky XD
See https://www.sumibe.co.jp/english/product/hpp/molding-compound/phenolic/index.html
"This makes it look like it loses at least 10% of its strength by 200C"
Remember that on track you will trying to get heat into the brakes to get the friction material up to temp. If you look at a track pad friction graph you will see they only get better as the temp gets over 200c.
The longer you stay out doing laps and harder you drive, the more likely these phenolics are to fail on you. We typically see the pads fade or the fluid boil first as a factor there. Caliper piston melting or cracking isn't really a normal thing.
As a final move I took the blowtorch and set it on fire - surface cracks appeared on the outside of the piston within seconds. Also the smell went from whisky to burning pvc. I could you could call this simulating putting the pads on fire. I've got (poorly edited) video of this if you want to see.
Tests suggested by @moca2cv aka John
God's work, Alex, thank you for doing this! Job for when it's time to replace the brake fluid next.