Big Brake Upgrade For Gtr

[JAGR33]

I use the Alcon kit, 6 front 4 rear, braking performance was improved immensly, still using standard master cylinder and brake booster...

My car is a street car aswell as a track car, don't see the point in changing anything else brake related. e.g pedal box, twin masters etc... I am definetly interested in trying different pads though...Using DS3000's at the moment...

Oh, and I have the Nismo brake ducts aswell for better cooling....

There are another 6 or so modified GTR's here in Vic that run the bigger brake setups and they too haven't changed boosters and master cylinders either....

[tacker]

me me me

i use brake ducts

[danoz]

I use the Alcon kit, 6 front 4 rear, braking performance was improved immensly, still using standard master cylinder and brake booster...

My car is a street car aswell as a track car, don't see the point in changing anything else brake related. e.g pedal box, twin masters etc... I am definetly interested in trying different pads though...Using DS3000's at the moment...

Oh, and I have the Nismo brake ducts aswell for better cooling....

There are another 6 or so modified GTR's here in Vic that run the bigger brake setups and they too haven't changed boosters and master cylinders either....

cheers mate that info is much needed. im lookin at ap and grec systems aswell same size so i think they all will work the same do all the guys run alcon or do some have ap and grex????????

[Roy]

I use the Alcon kit, 6 front 4 rear, braking performance was improved immensly...

I dont doubt they are working better then your old setup, as i have heard similar comments from ppl who have moved away from the F40/50 Brembos.

But when you say immensely, how do you measure it. My thoughts from what i have read and the very limited experience actually driving a few cars is the feel. That changes greatly. I have never driven one long enough or hard enough to feel the improived consistancy...but i think even looking at things on paper its a given they work more consistantly.

But does the car stop any quicker, and if so what sort of improvement? Can you honestly equate an improvement in lap time to the brake upgrade?

[JAGR33]

cheers mate that info is much needed. im lookin at ap and grec systems aswell same size so i think they all will work the same do all the guys run alcon or do some have ap and grex????????

One of the guys runs the full AP setup, another the same Alcon kit as me and a few with the Harrop full setup.

There's no one running the G-REX setup that I know of, so can't comment on them...

[JAGR33]

I dont doubt they are working better then your old setup, as i have heard similar comments from ppl who have moved away from the F40/50 Brembos.

But when you say immensely, how do you measure it. My thoughts from what i have read and the very limited experience actually driving a few cars is the feel. That changes greatly. I have never driven one long enough or hard enough to feel the improived consistancy...but i think even looking at things on paper its a given they work more consistantly.

But does the car stop any quicker, and if so what sort of improvement? Can you honestly equate an improvement in lap time to the brake upgrade?

My F50 setup was definetly much better than standard, although I was running standard rears that had not been touched since I bought it, and upon removing them, the rotors and pads were quite worn. So I guess with new rotors on the rear with decent pads, new rotors on the front and maybe a seal kit through the F50 calipers the setup might have been just as good as the Alcon kit I have now, but the availabilty of the Brembo F50 rotors and the money to freshen up the rear gave me the incentive to bite the bullet and get the Alcon kit..

I did not measure the braking performance by distance or lap times, but it felt much stronger under brakes, I guess new rotors/calipers/pads and great balance does that. I cannot compare lap times due to the fact my car has undergone more mods since the new Alcon kit went on the car, aswell as myself improving driver ability..

[phunky_monkey]

Well good luck getting service out of PWR for the Alcon gear. Maybe it was just me or my timing or something but I wasn't impressed by their lack of response or their prices. Racebrakes on the other hand couldn't have been more helpful (AP Racing)

I can't comment as I've never dealt with them myself, but a guy on the LS1 forums has been dealing with them and it seems that they are quite helpful. He's flying up there to trial there kits before he makes a decision, maybe you should contemplate doing that danoz? Try before you buy

[djr81]

Double post, sorry.

Edited March 8, 2007 by djr81

[djr81]

Hmm, computer not happy.

Edited March 8, 2007 by djr81

[djr81]

1. A long brake pedal (excessive motion)

This can & will happen if the new calipers you choose have too great a piston area. Remember bigger is not necessarily better.

2. A heavy brake pedal (excessive force required)

This is actually fairly difficult to achieve with the Nissan setups, but if you try hard enough...

3. An imbalance in the front to rear braking distribution (premature front or rear brake lock up)

An imbalance can quite easily occur. You need to carefully match the rotor diameters, piston areas, brake master cylinder to all work in harmony. If for example you end up with big front rotor with a small piston area you are pretty much guaranteed to prematurely lock fronts & actually degrade the overall braking performance. That is why you need to talk to the vendor & confirm that your chosen set up has been successful on someone elses car.

The things people need to measure are the following:

Longitudinal retardation.

Brake temperatures.

Rotor & pad life.

Obviously there are other subjective "feel" parameters but as often as not this is a function of the rotor & pad as much as anything.

With regard to my R32 R. It has standard brakes.

The maximum gees I can reach under braking is a little over 1. About 1.1.

The rears do lock before the fronts, but there isn't really enough braking power to lock the fronts from high speed with R compounds.

The three thermographic paint markers on the rotors have all flashed off & the rotors themselves show signs of surface cracking which is how you recognise a rotor that is working hard.

The rotor life sucks, but the DS2500 last well.

Yes I need better rotor cooling.

As an aside if anyone has the specs for the 4 pot Alcon gear, ie piston sizes, pad sizes, caliper weight/dimensions etc I would be interested in finding out what they are.

As another aside here is a cutout of the AP Racing CP5555 caliper & rotor failing to fit inside my 17" rims. (Previous post)

Edited March 8, 2007 by djr81

[Beer Baron]

Someone is about to trial some R32 GTR calipers on 340mm rotors. I was going to do it, but honestly im sick of wasting money trilaling stuff because im curious...my car is still slow. Any money i spend from now on has to make my car go quicker

yep, it's me. going to try for 340mm 2 piece rotor, standard GTR sumitomo caliper. I have already done about all I can to optimise what is there:

braided lines

master brace

good fluid

tried heaps of pads

DBA 4000 rotors all round

cut off the backing plates

the only think left I can think of is trying this bigger rotor, and also some ducting. I need to get my hands on some R32 GTR standard brake ducts as sadly mine were absent when I got the car. but I think with all the gear I have, and the 340mm rotor and some ducting the car should stop quite well for at least 4 or 5 laps. and hopefully the 340s + stock caliper will just fit under a 17inch rim (which is what I want to run).

[mad082]

no point having big brakes if you already lock tyres. bigger brakes will only cause more lockups. to effectively use bigger brakes you would need better tyres.

[Marlin]

I use the Alcon kit, 6 front 4 rear, braking performance was improved immensly, still using standard master cylinder and brake booster...

My car is a street car aswell as a track car, don't see the point in changing anything else brake related. e.g pedal box, twin masters etc... I am definetly interested in trying different pads though...Using DS3000's at the moment...

Oh, and I have the Nismo brake ducts aswell for better cooling....

There are another 6 or so modified GTR's here in Vic that run the bigger brake setups and they too haven't changed boosters and master cylinders either....

Yeah, we now use exactly the same setup, even the DS3000's, and it is superb.

After initially hoping that F40/F50's would suffice, we were sadly made aware that half way through one 6 day event, the genuine Brembo 2 piece rotors had several radial cracks and we were forced to "cruise", well, at least back off to 7 tenths anyway.

That was a bad enough experience to bite the bullet and get the Alcon's through PWR, and they were on the doorstep within a week, and were quite simple to fit.

Pedal feel is excellent (on the std master to my suprise), and balance seems quite good too judging by the wear and feel of the car. Pad knock-off however is more noticable due to the larger rotor diameter, though we may minimise that by tightening/replacing wheel bearings.

[danoz]

thanks heaps guys is seems to be the guys with the bigger brakes love them and the guys that dont have them bag them and say there not worth it. i have settled on 6pot fronts with 355mm rotors 4pot rears 330mm rotors with ds2500 pads for street and montly track work

[mad082]

i don't bag out bigger brakes cause i don't have them. i was just making a point that if someone is looking for a brake upgrade and are already locking up brakes then bigger brakes wouldn't help. better tyres would.

[Roy]

I agree with what you are saying Mad082. But thats not indicative of the whole truth. Driving a car fast is very much a confidence thing. So whilst the std setup is good, and the stopping distances are very dependent on tyres. Improving the feel and comfort of the driver is a big thing. Especially on tarmac rallies where concentration must be maintained. Worrying about how the brakes are feeling/performing is something you can do without.

So the feel you get from the more rigid calipers, larger rotors and improvements in consistancy is worth a lot. Even if physically the stopping distance is only 8mtrs better. But then again in tarmac style events often the difference between midfield and top of the field is less then 1/10 of a second per km.

So, looking at a thing like being able to lock brakes in isolation is neglecting so many other aspects of driving a car quickly.

[ferni]

Yeah, we now use exactly the same setup, even the DS3000's, and it is superb.

After initially hoping that F40/F50's would suffice, we were sadly made aware that half way through one 6 day event, the genuine Brembo 2 piece rotors had several radial cracks and we were forced to "cruise", well, at least back off to 7 tenths anyway.

That was a bad enough experience to bite the bullet and get the Alcon's through PWR, and they were on the doorstep within a week, and were quite simple to fit.

Pedal feel is excellent (on the std master to my suprise), and balance seems quite good too judging by the wear and feel of the car. Pad knock-off however is more noticable due to the larger rotor diameter, though we may minimise that by tightening/replacing wheel bearings.

What size rotor are you running under your R34 GTR rims?

[Marlin]

365 front and 335 rear. They're close, (and do get a few graunchy noises with rocks between the rim and caliper), but man they work well.

[Snowman]

I'm running the AP 6 pot CP5555's with 375mm rotors with the standard rear brake set-up.

I haven't altered anything else other than braided lines and a master cylinder stopper.

I'm very happy with the set-up as I found the original configuration to cause me to trail brake a little too much where as for me this set-up has balanced the car out under heavy braking.

[ferni]

365 front and 335 rear. They're close, (and do get a few graunchy noises with rocks between the rim and caliper), but man they work well.

Thats good to know that 365 with alcons fit under the R34 GTR rims...