Read on Spyderchat that the Prius XW20 brake calipers fit on the MR2. Being aluminium they are 1 kg each lighter and should dissipate heat a lot better and the Prius being some 30% heavier would make the calipers strong enough.
The piston diameter should not be an issue either.
If this pans out it would be perfect for me as painted red it would be an undetectable mod.
Has anyone here tried this?
Apart from a great kilo unsprung weight per wheel deleted, it would tickle me pink to have hybrid car calipers fitted O:-)
Front, rear or both? Got a link from Syderchat?
Quote from: JB21 on June 22, 2023, 16:09Front, rear or both? Got a link from Syderchat?
Front
https://www.spyderchat.com/threads/weight-reduction-odd-items.158153/page-32#post-2204921
Left
https://m.autodoc.co.uk/kamoka/19171256
Right
https://m.autodoc.co.uk/kamoka/19171257
Discs look the same too
https://m.autodoc.co.uk/brembo/7013615
I have been reading the thread. If this works it would be a big deal however with the larger piston it might take up more slack in the brake pedal but possibly not enough to notice. If it works it will a great upgrade for the money.
Quote from: Dev on June 22, 2023, 16:30I have been reading the thread. If this works it would be a big deal however with the larger piston it might take up more slack in the brake pedal but possibly not enough to notice. If it works it will a great upgrade for the money.
I'll give it ago, not sure if you'd need the prius brackets as well though. Will follow the thread as see how it progress.
Quote from: JB21 on June 22, 2023, 16:32I'll give it ago, not sure if you'd need the prius brackets as well though. Will follow the thread as see how it progress.
It's cheap enough to find out and that is appealing because I would not trust some random person on the internet just because it fits. One of the things I like about my Wilwood calipers is the reduction in the travel of the brake pedal which makes the pedal feel firm but also well modulated.
Quote from: JB21 on June 22, 2023, 16:32I'll give it ago, not sure if you'd need the prius brackets as well though. Will follow the thread as see how it progress.
I hópe not as that would make me feel uneasy about switching sides.
Will give the local parts source a holler too mañana.
Quote from: Dev on June 22, 2023, 16:41It's cheap enough to find out and that is appealing because I would not trust some random person on the internet just because it fits. One of the things I like about my Wilwood calipers is the reduction in the travel of the brake pedal which makes the pedal feel firm but also well modulated.
Not looked but I bet there isn't an abundance of track pads available 😄
Quote from: JB21 on June 22, 2023, 16:47Not looked but I bet there isn't an abundance of track pads available 😄
It is not exactly the same price range either ;)
I can only find EBC greenstuff. Funny as the dimensions are similar to the MR2 front pad but they look slightly different in shape.
Prius pad:
(https://i.postimg.cc/nrNHPnTJ/Screenshot-20230622-171158-Samsung-Internet.jpg)
MR2 pad:
(https://i.postimg.cc/Dzf8syMj/Screenshot-20230622-171420-Samsung-Internet.jpg)
@thetyrant could you make pads for the Prius backing plate?
Quote from: JB21 on June 22, 2023, 17:21@thetyrant could you make pads for the Prius backing plate?
8)
It's an interesting idea but Prius brakes are intended to work with regenerative braking. I'm not sure what the implications of this are but one of the problems with running a hybrid or electric car is the corrosion of brake disks due to under use. I wonder how they'd hold up to use on a sports car where they'll be used a lot more and get a lot hotter.
I will give it a try.
Have no doubt whatsoever that they will be more than up to it; the Prius being heavier and aluminium dissipating more heat.
The Prius is designed to seat 5 plus luggage. Our cabrio for 2 and their tooth brushes.
Just bought a set revised ones. Come with the Prius sliding brackets. Should be here for 77.95 incl. shipping.
Toes crossed too ;D
Would suggest changing the title of this thread to something a little more meaningful and relevant
@Petrus Would certainly help the search function.
Nah, this is fun 8)
But don´t worry: Will make a new thread with pictures later. Sofar it is only a left field idea, not done and dusted yet.
Quote from: Petrus on June 23, 2023, 07:34Nah, this is fun 8)
But don´t worry: Will make a new thread with pictures later. Sofar it is only a left field idea, not done and dusted yet.
Have you considered that the spurious title might stop people reading, and therefore contributing to this thread?
Those people may have information that we are not privy to.
Meanwhile cýcled in line of Operación Tripa also past the local garage as the calipers will be delivered thére.
Quote from: Alex Knight on June 23, 2023, 09:16Have you considered that the spurious title might stop people reading, and therefore contributing to this thread?
Those people may have information that we are not privy to.
Flogging... dead... horse.... But more power to you for trying.
Quote from: Call the midlife! on June 23, 2023, 10:45Flogging... dead... horse.... But more power to you for trying.
😂
Very apt btw. I have a website about horse training. Among other aspect, you get what you reward.
Quote from: JB21 on June 22, 2023, 17:21@thetyrant could you make pads for the Prius backing plate?
Just seen this sorry, yes I can make anything here :D
Quote from: Petrus on June 23, 2023, 11:02Very apt btw. I have a website about horse training. Among other aspect, you get what you reward.
I don't think you understand the meaning of the phrase I used in my comment to Alex, in the same way I don't understand what you saying here.
We'll leave it at that.
I see the update on this in Spyderchat is very positive, and you can actually use the MR2 brackets meaning you can use MR2 pads.
Quick check and seems Early Prius use same front pads as Mk3 MR2 anyhows :D
Quote from: thetyrant on June 27, 2023, 10:55Quick check and seems Early Prius use same front pads as Mk3 MR2 anyhows :D
These calipers are from a MK2 Prius 2004-2009, still the same?
Will know soon enough.
Quote from: Petrus on June 27, 2023, 11:50Will know soon enough.
Me too, just purchased a refurbished set myself. £96 delivered. I needed to refub my current MR2 front calipers so this saves me the hassle as well as the bonus of weight saving and a bit more front bias.
Quote from: JB21 on June 27, 2023, 11:54Me too, just purchased a refurbished set myself. £96 delivered. I needed to refub my current MR2 front calipers so this saves me the hassle as well as the bonus of weight saving and a bit more front bias.
Win
3Have the RAL3000 rattle can waiting.
Véry much chuffed there is no mod to the brake lines/fittings needed.
Quote from: JB21 on June 27, 2023, 11:08These calipers are from a MK2 Prius 2004-2009, still the same?
Yes all same from what i can see until mk3 w3 1.8 Prius
Be interesting to see how the larger piston affect pedal feel and bias, hopefully not too bad
Quote from: thetyrant on June 27, 2023, 11:57Yes all same from what i can see until mk3 w3 1.8 Prius
Be interesting to see how the larger piston affect pedal feel and bias, hopefully not too bad
Probably a bit more pedal travel, but shouldn't be dramatic.
Quote from: JB21 on June 27, 2023, 12:05Probably a bit more pedal travel, but shouldn't be dramatic.
Would surprise me if noticeable.
But then we will find out.
I find all the ´footnotes´ about possible effects a bit relativated by the total absence of ány observations about the effects on brake ballance of changes in front tire size.
Piston size and pedal travel are funny things, there are lots of calcs you can do and lots of theory etc but often the only way to know for sure is try it on a car when its pretty close like this, sometimes its surprising how much difference a small change makes and other times you can go with lot more piston area and it feels the same, lot to be said for the design of the calipers etc as well but i think it will be ok in this case but we will see!
I have to agree. Just because it fits or is larger doesn't mean it will jive well with the system as a whole.
You could end up getting worse brake feel and modulation. What it can do is feel like a two stage pedal that has play for the take up and then it gives you abrupt braking. This is why the master piston diameter and stroke should be matched to the caliper piston size.
I think it a great idea which everybody can but nobody needs to try.
My set will be delivered tomorrow so I'll get these fitted over the weekend and I'll report back. I've got a new set of Dixcel race pads to throw in, but I'm going to use the current PBS pads first to get a fair comparison MR2 caliper vs Prius caliper. I'll go out on the MR2 calipers and PBS pads first for a conditions test doing lots of braking from various speeds, then change straight over to the Prius calipers and PBS pads and retrace my steps for a true comparison.
Quote from: JB21 on June 28, 2023, 10:20My set will be delivered tomorrow
They´ll make you smile. I did ;D
Calipers arrived but there's a problem. One has been rebuilt with a Phenolic piston, the other steel.
Not sure which to replace?
The steel one looks like it could be to big to press on the whole of the brake pad.
On the other hand will the plastic piston be up to the rigour of heavy track work.
Edit: looks like the phenolic pistons are discontinued anyway.
(https://i.postimg.cc/DwSFs0Jz/20230629-102609.jpg)
The discontinuation answers why the the other is steel.
Does not answer your question about whether it is up to track use. Basically underlines that question with ´why discontiuned´ . Can be simply cost of manufacture but for the moment it´s a question.
Is it phenolitic ´plastic´ though. In the specs they are mentioned as ceramic.
As to the shape of the steel one, are the steel backings of the pads not stiff enough?
Back to the weight: Like it?
Quote from: Petrus on June 29, 2023, 11:00The discontinuation answers why the the other is steel.
Does not answer your question about whether it is up to track use. Basically underlines that question.
As to the shape of the steel one, are the steel backings of the pads not stiff enough?
Back to the weight: Like it?
Crazy light yeah.
I'll go with what I know in steel. I'll dry test fit first with the MR2 brackets to make sure there's no overhang of the steel piston to the pads, hopefully wont be an issue but the difference between to 2 piston contact patch widths is 7mm. Plastic contact patch is 47mm, steel 54mm. Even if there is a slight overhang I dont think it'll make much of a difference.
From memory of the inner pad imprint on the MR2 51mm piston there is plenty of room for the extra 3mm diameter of the 54mm Prius piston.
Quote from: JB21 on June 29, 2023, 11:10Crazy light yeah.
8)
[quore]
Even if there is a slight overhang I dont think it'll make much of a difference.
From memory of the inner pad imprint on the MR2 51mm piston there is plenty of room for the extra 3mm diameter of the 54mm Prius piston.
[/quote]
There is also an up side as it also means a wíder contact area on the pad i.e. abetter spread on the total surface.
For road use, even the most spirited, I only see wins.
Looking forward to your vision on the proof of the puddin´.
Steel pistons are 200g heavier then the OE Phenolic pistons.
1.3kg v 1.5kg
(https://i.postimg.cc/FH32fTrr/20230629-111730.jpg)
(https://i.postimg.cc/j5g9V9XX/20230629-111758.jpg)
Quote from: Petrus on June 29, 2023, 11:238)
For road use, even the most spirited, I only see wins.
Presumably yours have come with Phenolic pistons? Won't be an issue on the road if so.
Quote from: JB21 on June 29, 2023, 11:25Presumably yours have come with Phenolic pistons? Won't be an issue on the road if so.
Or ceramic? Not steel.
Indeed, even here in the hót south it will be ok regardless. Not doing heroe stuff steeply downhill anyway. My common sense prefers to have gravity on my side O:-)
Quote from: JB21 on June 29, 2023, 11:23Steel pistons are 200g heavier then the OE Phenolic pistons.
1.3kg v 1.5kg
Thanks for that bonus info!
Quote from: JB21 on June 22, 2023, 16:19Left
https://m.autodoc.co.uk/kamoka/19171256
Right
https://m.autodoc.co.uk/kamoka/19171257
Discs look the same too
https://m.autodoc.co.uk/brembo/7013615
Are the kamoka OEM? I am about to order a set from autodoc :)
Quote from: Nvy on July 2, 2023, 16:46Are the kamoka OEM? I am about to order a set from autodoc :)
Not sure mate, one of them isn't in stock either.
Quote from: Nvy on July 2, 2023, 16:46Are the kamoka OEM? I am about to order a set from autodoc :)
As far as I could find Kamoka is one of three OEM suppliers. Could be more even. But then they made a whooooole lot more (1,192,000-second-generation Priusii sold worldwide) than MR2s. Which is another reason to have sóme confidence in Prius calipers.
Confirmation Prius II pads are the same fitment as MR2 MK3.
(https://i.postimg.cc/Qxmk3XH3/20230703-103041.jpg)
Quote from: JB21 on July 3, 2023, 10:33Confirmation Prius II pads are the same fitment as MR2 MK3.
(https://i.postimg.cc/Qxmk3XH3/20230703-103041.jpg)
Tatáááá and yet anóther thank you for the confirmation.
Quote from: JB21 on June 22, 2023, 17:21I can only find EBC greenstuff. Funny as the dimensions are similar to the MR2 front pad but they look slightly different in shape.
Prius pad:
(https://i.postimg.cc/nrNHPnTJ/Screenshot-20230622-171158-Samsung-Internet.jpg)
MR2 pad:
(https://i.postimg.cc/Dzf8syMj/Screenshot-20230622-171420-Samsung-Internet.jpg)
@thetyrant could you make pads for the Prius backing plate?
Red Stuff DP31459C is dedicated for Prius and MR2 ZZW30.
MR2 prefacelift and facelift model has different break pads number 04465-17100 vs 04465-17140, but probably there is no difference.
https://rcagarage.com/shop/brakes-rotors-pads/brake-pads-performance/ebc-03-07-scion-xa-1-5-redstuff-front-brake-pads-dp31459c/
Quote from: Alex Knight on June 23, 2023, 09:16Those people may have information that we are not privy to.
Meanwhile done over 750 kms with them and in my blissful ignorance like it. Just immensely enjoyed the archelogical museum. Lots of hispano-roman good luck charms. I have a replica of one of those which is the tack room somewhere. Nice one for the MR2 key! 8)
Minus 1.2 kg on each front strut! That is tempting, I just bought a set. Just hope they fit under 15" Volk Ultra Racing CE28 Club Racer
@towWhat did you go for?
New, refurbished, used?
https://www.ebay.com/itm/373576614101
Aftermarket, I guess, on the pictures it looks like they have phenolic pistons. If they work it's a real bargain! Added bonus, as the front calipers on one of my MR2s has a cloinky noise, the pads work themselves lose, I have to tighten the small springs around them now and then.