Scoobs_4ever

Doh - working this weekend but seriously thinking of going to TSL on their open day.

[Edited by Scoobs_4ever - 11/2/2002 7:11:42 PM]

Scoobs_4ever

I've been picking up all sorts of advice about upgrading my MY98 2-pots to STi 4-pots but something has been bugging me all along.

I know it sounds obvious but stay with me.

Braking is a function of friction and how hard the pads can grip the disc. Simple so far. The major worry with the 2-pots is the brake fade under heavy braking due to heat. I believe this is because of poor heat disapation through the cast iron callipers.

So surely the Sti 4-pots, which are also cast iron, will also suffer from the same problem??

The other thing that bugs me too, is that even with my 2-pots I can get the ABS to function, so pressing harder with 4-pots will only make the ABS come on sooner??

Correct me if I'm wrong, but the larger disc sizes possible with the 4-pots can't be the only reason for exchanging with £600 when about £300 will get me a set decent pads and discs for a 2-pot.

yours really confused
Andy.

stockcar

unlike some, i quite often recomend sticking with the 2pot caliper - with the right pad / disc combination these can be an excellent set up!
why are you worrying about FADE is this something that your experiencing?? what pads/discs do you use know??
the 2pot will never match the 4pot side by side but depends on your depth of pocket / driving style / etc..
mail me for specific advice or post!!
alyn - as performance

p.s. we currently run a legacy turbo estate "chase car" with PAGID "blues" and grpN discs on 2 pots and its mint!!!!!

[Edited by stockcar - 10/28/2002 9:26:19 PM]

Scoobs_4ever

My current brake setup is standard Subaru dealer supply and due for replacement as the discs are becoming 'ridged'.

Normal driving style is fairly probs slow for a Scoobs but I generally travel between 50 and 70 with the odd thrash to overtake.

I've only suffered brake once, when I over shot a T-junction which frightened the crap out of me but it was during a thrash moment whilst braking from 100mph+

The other bit I would like to consider is poss future upgrades. I reckon with a filter +sports cat exhaust system, lowered suspension and a phase style ecu upgrade - these would require some better brakes than standard 2-pot.

I'm not into track days, just use my Scoobs to back and from work.

Any advice will certainly help.
Cheers
Andy.

dnb

I upgraded to 4 pots about two months ago. (took a long time to get them on the car - a long story )

I found that I could fade my standard 2 pots at least once every time I took the car out for a blast. I could have simply upgraded the discs and pads, but that is a bit of a dead end for further improvement.

I found some second hand (about 20k miles on them IIRC) 4 pots & discs on Scoobynet for a very good price (a good set of pads & discs for the 2 pots), and even standard (with mintex standard compound pads) they don't seem to fade at all (yet!)
They were also an easy DIY fit.

Yes, there is more disc and caliper area, so better heat dissipation & heat capacity, and the 4 pots push more evenly on the pads. Not to mention they look much better behind the wheels

I'm no brake expert, but I'm very satisfied with my standard 4 pots - I thought it was quite a big improvement, but I have never driven a car with upgraded 2 pots to compare.

Jay m A

iTrader: (2)

I have run 2pots until very recently. I upgraded the disks and pads to pagid grooved discs and FR pads, fitted braided hoses and 5.1 fluid. the only time I experienced braking problems was when I believe I boiled the fluid on a trackday at Outlon Park. This happened after 3 big stops (a hairpin and 2 chicanes) within 40 secs of each other. I never got fade on the road.

Justin

TonyBurns

iTrader: (3)

The newer 4 pots fitted to the STi and MY99 onwards are bigger than the 2 pots, this will disipate heat better and also they are fitted with a venting system in the front bumper than flows cold air onto the brakes, this also aids cooling (you can buy these from scoobymania).

Tony

Scoobs_4ever

Cheers guys.

I'll probs have a tour round TSL, Graham Goode and Scoobymania as they're all within 20mins drive.

probably be staying with 2-pots but upgrading discs, pads and hoses with 5.1dot brake fluid.

Andy.

stockcar

just a quick one about 5.1 fluid - this is (sometimes) not as good as it sounds
you will find most "ccompetition" fluid is ONLY dot4 however it will almost cetainly be better than 5.1 in resisting fade as it normally has a higher / more stable boiling point!!
5.1 is only better at resisting moisture
alyn - as performance

scooby_si

Just swapped from 2 pots on me MY97 to 4 pots off a fellow Leicester type (£300) & did braided lines etc at same time & even using the cheaper pads (green stuff) braking is certainly better
Si
BTW u wana join us lot this Sunday at Cov area meet there's a few kum from Leicester & yer more than welcome

scooby_si

& i fink, been known 2b rong, that because there is more friction with the 4pots over 2's that they dont lock up quicker than 2 pots & thus ABS wont kick in any quicker but u will slow down faster Since the load is dispersed over larger area so will still lock up when stamped on but the slow down up2 that point is quicker, erm am i prattling, maybe but that's my understanding limited as it is if that makes any sense lol
Si
Really dunno as that made any sense but 4 pots = more friction = slow down quicker with or with out getting 2 lock up point

Jay m A

iTrader: (2)

Good call with the fluid, I now run with the Castrol stuff (£10 a litre from Halfords I was in a rush!) which they say is DOT 4+, suitable for motorsport. Yet to be put to the test but at the time I only had a choice between this and Halfords own 5.1 fluid. Having read other posts on here about the pros and cons of DOT4 v DOT 5 I went for the castrol since I change the fluid at least once a year anyway.

Justin

Catalunya 051

Scooby-4ever: I recently did the 2 to 4 pot conversion and put Tarox G88 40 groove disks on all round (rears needed changing badly). I agree that the stainless hoses do improve things but it is best to put them on all four corners, you risk damaging the rear ones if you only do the fronts! The grooved disks work well with OE pads as I have found pad upgrades tend to eat OE disks and as a disk is far more expensive I reckon you play about with the thing that will stop the fade (which if your pedal went rock hard and your brakes stopped working was due to pad/disk/caliper heat, if the pedal went soft it was fluid heat) which from what I have read is gas build-up between pad and disk. Grooved disks clear this and it worked for me. The other advantage the 4 pots have over the 2s is that they have an open back structure which allows better airflow from the pads where they meet the disk. The 2pots didn't provide this. You can get 4 pots pretty cheap on here, I got a set with pads (no disks) for £300 on my doorstep, delivery mileage only (P1 had upgraded to Alcons for track use). I would say it's the only way to go.

Scoobs_4ever

I keep changing my mind more time than the weather at the mo.

I've bitten the bullet and placed an order with Godspeed for a 308mm kit upgrade.

But seriously, thanks for all the help and comments everyones made. Put my faith back in ScoobyNet that there are some real good genuine people who like to help.

Cheers
Andy.

scooby_si

Fancy kumin on Sunday then 2 meet sum genuine peaps i hear the weather will b gr8, well ok but we r genuine
Si

ChristianR

iTrader: (1)

i have sti 4pots for sale if interested, drop me an email.

Scoobs_4ever

Too late - Ian's sorting me out.

Thanks for the offer tho.
Andy.