Brake options

[monkeymax]

Bias valve as standard doesn't split it 50/50 though. As Paul says, it's 55/45 which would change your numbers slightly... This gives a standard bias of 71% at the front by my quick calculations... (which actually sounds quite high)

[mr2mk1chick]

stock brakes,even when working 100%,fade too quickly under hard braking conditions,they simply arent dealing with the heat produced quickly enough.This is not really noticeable on the road but on track you can feel how inadequate they are.

.....when was your last track day Paul? (maybe better pads out there since your experience?)
Do you have a really heavy braking driving style or something?

I have never had any problems with the std discs and really well maintained callipers, dot 5.1, braded lines, and good spec pads.
i do admit to probs with pads such as green stuff and black diamond somethings....

Seems to be a few peeps here thinking the same- std is fine even for SC's

[MartG]

Can't find my calculations at the mo, but I did work out a while back that removing the bias valve when fitting ST165 twin pots at the front kept the bias pretty much as standard

[Tom G]

Bias valve as standard doesn't split it 50/50 though. As Paul says, it's 55/45 which would change your numbers slightly... This gives a standard bias of 71% at the front by my quick calculations... (which actually sounds quite high)

damn right it's high! and upgrading the fronts just makes it worse

Can't find my calculations at the mo, but I did work out a while back that removing the bias valve when fitting ST165 twin pots at the front kept the bias pretty much as standard

don't think it's quite enough... I gutted mine and still wasn't right, but one wonders what the point is when you end up where you started adding 22V rears brings it back to std bias, but personally I'd rather have more at the back, I'm thinking of reverting back to mk1b fronts for a 59/41 split.

[Matt_J]

In hundreds of trackday miles in my MK1 ScC and 2 seasons in the mr2 challenge I never suffered from fade using stock discs and calipers.

I just used expensive Porterfield race pads and some specials that Chris Wilson had made. Chris' pads were best but the Porterfields weren't far behind.

I also ran a Sprint and trackday season in the ex Granville Williams kevlar bodied mk1 with 300mm Hispec 4 pots running Ferodo DS 2000 pads and arguably this had better brakes, but they were harder to control around the lockup limit, being a lot more grabby.

regards

Matt Jenkins

www.team-dandism.co.uk

[weegaz22]

yes the st165 or 185 brakes work,ive never had a problem with wheel fitment.

completely agree, putting on bigger front discs/calipers off a celica does reduce fade but messes up your bias, making it very easy to lock up the fronts, especially in the wet... I would say dangerously so.... and upgrading the rears doesn't compensate

im sorry,i dont mean to argue but this statement is not true,i had huge st205 4 pot calipers and 300mm discs on my last mk1 and it didnt upset the bias at all and it didnt lock up easier.If anything id just made the car stop very very quickly,almost an ABS feel.

Reason being you are moving the same amount of fluid but to more pistons,this results in an overall better braking with less fade at the expense of slightly more pedal travel.

If its a concern then gut the bias valve to make it a 50/50 bias instead of 55/45,but its honestly not needed.

Also under heavy braking the weight transfer is thrown forward onto the front wheels,so ideally you want more stopping power up front anyway.

The celica upgrades tick all the boxes while keeping it toyota.

seconded, i have an st205 setup on my car and its a very good setup, there are no bias issues with locking up the fronts, sure, you can lock them up if you try by stamping on the pedal like an idiot, but on mines once you get the weight transfered onto the front you can keep pressing that pedal till your eyes pop out your head without it locking up, decent tyres and suspension help as well

and as for stock brakes being fine, sure for everyday driving/commuting they are, but if they are going to be used in anger then you want to be upgrading, specially if your engine is uprated, you dont want to stab the brakes and find you have past the point where they keep fade at bay

[PW@Woodsport]

.....when was your last track day Paul? (maybe better pads out there since your experience?)
Do you have a really heavy braking driving style or something?

hi jo,i dont think my personal driving style is relevant,im going off feedback from countless customers who do a lot of track work,all of whom have said the stock brakes overheat and fade whereas the celica ones dont.

Dont take my word for it,give the celica calipers a try for yourselves,they dont cost much and take 20 mins to change.

thought you had to drill an additional hole to match the PCD of the mr2 hub studs?

no,the st165 and 185's use the stock 1b disc,its only when you fit the st182 277mm braked calipers or the st205 315mm that you need to drill the 277 celica disc.

[dgh.mr2]

I also ran a Sprint and trackday season in the ex Granville Williams kevlar bodied mk1 with 300mm Hispec 4 pots running Ferodo DS 2000 pads and arguably this had better brakes, but they were harder to control around the lockup limit, being a lot more grabby.

regards

Matt Jenkins
www.team-dandism.co.uk

I was wondering about chucking my 2 pence worth in before seeing this - hello again Matt, I wondered if you were still keeping up with the MR2 world having lost touch since you stopped competing in the challenge! - so here goes.

The car mentioned - once re-built - had standard brakes front and rear and initially they were dire. We put new fronts on (disc and calipers + braided lines), still dire. Then Toni gave me a warning that sticking rear sliders (I think) could affect the whole system so we re-built the rears and suddenly hey presto they were fine.

So, that is where I'd start, checking out the existing system and using decent pads. We tried a number over the years and I liked Mintex and Porterfiled; DS2000s and EBC less so.

The 1.5 I bought with Celica system had awful brakes - so soft and mushy and with so little effect even with 'foot flat to the floor' they were more frightening than it's lousy handling (down to its build - loose/ corroded suspension bits/ mountings etc. - not an issue inherent to 1.5s I should add). I had them bled and re-filled with a good quality road spec. fluid and found no improvement. Whether this was an install issue or the effect of the change on the ratios/ balance being discussed I never knew (I panicked, got disillusioned and bailed out before getting it sorted unfortunately.)

Further changes to the track car before Matt used it gave - still with the standard rears - 310mm x 28mm front discs and 4 pot alloy calipers from Hi Spec. They needed to be set-up v. carefully and machined as they didn't come 'right' from Hi-Spec. (pad not running against disc properly) allegedly not an uncommon problem!

They are fantastic on track (very powerful and never a hint of fade) but are sensitive and do lock up at the front v. easily even in the dry - always on road tyres for me. I got used to this and so could drive around it or cope (e.g. front locks, briefly off the brakes and back on more smoothly and off avoided!) and the car could out-brake almost anything on track gaining loads of time (sometimes 50m or more on faster cars that had passed on the straight). As an example the braking point on the pit straight at Donington was well past the pit lane exit and into the marked corner warning/braking area. I've watched many race cars in testing and competition to see where they can brake and not many leave it later, 'though of course are braking from a higher top speed.

In the wet it is more difficult. Overall though, for my level of driving I'd prefer not to have too much rear bias to avoid surprise rear lock ups causing a potential spin which I see so often in professional race cars/ series.

I'm now about to fit a complete new system from OBP - new floor mounted pedals and master cylinders/brake balance bar with the leverage rates etc. specced by them to my request and adjustability front to rear. I'll report back once I've had some experience with them on both road and track.

[Keri-WMS]

Sorry to resurrect this but I've been dying to join in the conversation for ages! We have another option for the AW11, but couldn't discuss it until I got affiliated.

First off, I agree that most people will find their stock brakes are fine if they are working perfectly.

Second off I'm not going to get into the pad choice debate. My personal opinion (take it or leave it) is to say that if I ran EBC I would drop the Green due to the damage it does to the reputation of the Red/Yellow which are in another league. The best pads I know of from their reputation are Carbotech, followed closely by Pagid.....but we have dealt with race cars running Reds happily on 280mm discs and big-hp V8s so you may not need to stretch to the cost of Carbotech etc.

Thirdly, I agree that the AW11 doesn't need more front bias, but the fronts can be prone to overheating, and the OEM calipers are very heavy.

So, all that said, here's that other option, the WMS kit. For full details please see the thread in affiliates here: ( www.imoc.co.uk/forums/viewtopic.php?t=128889 )



While we're on the subject, who's running what mechanical brake upgrade (ie excluding disc/pad brands)? Vote with your feet people, be interesting to get some idea! I know what loads of you are running but it's not my place to give the game away...

WMS 4 pots
1 - Me!
2 - Jim-SR (I still need to sort you some alloy bells, I know! )
3 - Nik of TB's Mk1.5 before he sold it.
4 - eRATic (based on www.imoc.co.uk/forums/viewtopic.php?t=106141)
5 - MarcsMR2 (based on www.imoc.co.uk/forums/viewtopic.php?t=48298)
6 - superchargedsam (based on www.imoc.co.uk/forums/viewtopic.php?t=73609)
7 - ?

ST205 Celica 4 pots
1 - ?
2 - ?

ST185 Celica
1 - ?

ST165 Celica
1 - MartG
2 - ?

AP Racing 4 pots
1 - tonigmr2
2 - ?

BMW 4 pots
1 - Paul (325mm) + 320mm/22v rear

Bremsport 4 pots
1 - aw11rally (310mm)

HiSpec 4 pots
1 - Limeymk1 (285mm) + stock rear/Pagid pads

...others...?

Post is being edited as people's setups are added....

[MartG]

ST-165 4 pots on the SC track car ( with bias valve removed ) - not sure if they are the same as the early ST-185 ones

Just std calipers all round on the road SC

[PW@Woodsport]

My v8 mk1 has 325mm BMW front discs and porsche 996 4 pot radial mount calipers.... at the rear it has 320mm rx8 front discs on modified rev2 mr2 calipers.

[Keri-WMS]

ST-165 4 pots on the SC track car ( with bias valve removed ) - not sure if they are the same as the early ST-185 ones

I thought the ST165 had 2-pots on sliders?

[aw11rally]

fronts:- Bremsport 310mm rotors with 4 pots, alloy bells, rotory bias valve
rear:- Mk1a fronts, standard disc, 7 position lever bias valve

opinion:- Amazing, unbelievable, painful, infinitely adjustable, very controllable, maybe a bit of overkill but it is a tarmac rally car. Biggest problem is that we have to run min 16in wheels which limits tyre choice some what as most of the best (and cheapest) rally slicks come in 14,15,17in. We use R888's to good effect though but they generally only last about 100miles.

[tonigmr2]

I have a custom AP set up on the front of my TC including discs and calipers.

[Kooga]

Joining in from a road user only perspective...I fried my standard set up on a 'spirited' morning drive not long after getting the car. I immediately fitted stainless hoses, DOT 5.1 fluid, pagid pads and black diamond discs. I didn't like the pads as they had very poor feel, were useless cold and wore the discs at a rate of knotts, so swapped to EBC green stuff all round. Have had no probs at all with this set up, and it can stand the car on its nose throughout most use - which makes me happy. That said, with any lengthy spirited driving, you can tell they are verging on fade as the feel starts to go a bit woolly. So I can imagine an upgrade would be helpful keeping the fronts cool...unless removing the guards makes a big difference to cooling?
P.S has anyone found a cheap source of copper washers for the banjo bolts as toyota are taking the P (capital) with their £1.20 PER WASHER!!

[System-G]

Pagid don't make pads for the AW11 anymore and haven't done so for nearly 4 years

[Keri-WMS]

Pgid don't make pads for the AW11 anymore and haven't done so for nearly 4 years

I'd heard that. They do (or did last time I spoke to them) pads for the WMS calipers though....I got a quote for a customer and it was "not cheap"!

[System-G]

Pagid still make race pads for loads of callipers - we used to use them exclusively on all our Caterham Race & track cars, but have recently switched to Mintex C-Tech race pads - also sadly not available for the AW11, but are slightly cheaper and longer wearing/less abrasive to discs than the Pagids are.

[MartG]

ST-165 4 pots on the SC track car ( with bias valve removed ) - not sure if they are the same as the early ST-185 ones

I thought the ST165 had 2-pots on sliders?

Sorry - typo

[Keri-WMS]

ST-165 4 pots on the SC track car ( with bias valve removed ) - not sure if they are the same as the early ST-185 ones

I thought the ST165 had 2-pots on sliders?

Sorry - typo

Ah-ha! Had me going for a sec there...