Stoptech Brakes

[Roy]

But Wakefield is a play ground. Front straight you are stopping from about 180-190km/h to about 120-130km/h...then on the back straight there is a similar stop but probably back to 70km/h.

It is a short track so there isnt much time between those stops so in turn time for brakes to cool. Calder is about the same distance and look at its stops! Ditto Sandown which isnt too much longer and look at those stops. These places are much harder on brakes.

Also, you have just posted that we cant get the DBA stuff for the same prices as you, we dont know how to machine down the rotors to suit the required diameter and offset...so i stand by the fact that the the value isnt there when the Aussie dollar is doing so well.

Also, you mentioned you sold your near new DBA4000s, what did you pay for them and what did you sell them for. If you are going to claim the dollars you got for selling them, then you need to consider the original spend on buying them for the one track day You will find you lost money, so cant claim it agaisnt the cost of the other gear because you sold it

I tend to agree that the spacer and 324mm setup is a good setup. But again, DBA charge the earth for replacement rotors, charge the earth for the original rotors, and having now sampled the F40s i dont want to go back to the comparitively woeful pedal feel of the std caliper, especially since i dont have ABS and like you state, the setup has no problem lockign brakes well into a session.

For me that is the major problem, the temps everything is running at and the loads i am putting through them, well everything gets that little bit vague which means i am lockign brakes, which at places like the front and back straights at Calder, and frotn staright at Sandown, well is doing horrible things to my tyres. Hell the brakes will pay for themselves as they will stop me flat spotting my tyres, thats assuming they feel as good as the F40s did on my car

[Roy]

The radius difference (140mm versus 170 mm) is too small to have any effect on the curvature of the pads versus the curvature of the rotors. Even if it did, and it doesn't, all I would have to do is trim the centre of the pads a mm or 2 to match the curve.

I am not so concerned about the difference in pad to rotor, its the caliper to rotor. The caliper is designed for a rotor of 140mm radius, so using them on a 324mm rotor with a radius of 162mm means that the caliper offset is not simply 22mm. If you measure up the adaptor its not simply an offet 22mm adaptor, going to 340 is only going to mean the caliper rides higher up on the rotor as the calipers internal radius has to be compensated. I would be surprised if you measured up your adaptor that it has 30mm offset holes?

[Sydneykid]

But Wakefield is a play ground. Front straight you are stopping from about 180-190km/h to about 120-130km/h...then on the back straight there is a similar stop but probably back to 70km/h.

It is a short track so there isnt much time between those stops so in turn time for brakes to cool. Calder is about the same distance and look at its stops! Ditto Sandown which isnt too much longer and look at those stops. These places are much harder on brakes.

Also, you have just posted that we cant get the DBA stuff for the same prices as you, we dont know how to machine down the rotors to suit the required diameter and offset...so i stand by the fact that the the value isnt there when the Aussie dollar is doing so well.

Also, you mentioned you sold your near new DBA4000s, what did you pay for them and what did you sell them for. If you are going to claim the dollars you got for selling them, then you need to consider the original spend on buying them for the one track day You will find you lost money, so cant claim it agaisnt the cost of the other gear because you sold it

I tend to agree that the spacer and 324mm setup is a good setup. But again, DBA charge the earth for replacement rotors, charge the earth for the original rotors, and having now sampled the F40s i dont want to go back to the comparitively woeful pedal feel of the std caliper, especially since i dont have ABS and like you state, the setup has no problem lockign brakes well into a session.

For me that is the major problem, the temps everything is running at and the loads i am putting through them, well everything gets that little bit vague which means i am lockign brakes, which at places like the front and back straights at Calder, and frotn staright at Sandown, well is doing horrible things to my tyres. Hell the brakes will pay for themselves as they will stop me flat spotting my tyres, thats assuming they feel as good as the F40s did on my car

The "20 minutes at Wakefield" is consecutive, one driver in, one driver out. No sitting around having a chat for an hour till the next session. We do 4 session back to back, then 30 minutes off, then another 4 sessions. Don't underestimate the effect of the simple scoops on the R33GTST or the full ducting on the R32GTST and I stand by my pad choice, which is the same compound as we used in the 12 Hour. The Wakefield example was exactly that, an example. Would it better if I used Oran Park as an example, we don't get over 550 degrees of rotor temperature there (paint tested). I haven't been to Calder in a while, but it wasn't ever as tough on brakes as Oran Park, ditto Winton and Philip Island. I can't say as we have ever had a brake problem at Sandown and we won the Vic IP Racing championship in the RX7 with tiny brakes by the standards you guys are talking about.

Not that it matters, but that particular set of DBA 4000 rotors were free, I didn't pay for them as they were experimental in their slot design and I tested them under race conditions. The wiper slots worked fine, the rotors themselves were just a bit small in diameter for my purposes. I have used DBA stuff for a looooong time, as well as them sponsoring the race series, so I get stuff at the right price plus the occasional test set. Whereas guys who swap brands like their socks don't get the same treatment. Brand loyalty and familiarity has its advantages.

If the cooling isn't sorted out, it is easy to can cover up for that deficiency by by sticking on ever larger rotors and/or callipers with more pistons. But all it does is add extra unsprung weight, the cooling problem is still there. By any standards V8 SuperCars have decent sized callipers and rotors, but they still run massive scoops and ducting. There are lessons that all of us can still learn just by observing what the pros are doing.

Cheers

Gary

[Sydneykid]

I am not so concerned about the difference in pad to rotor, its the caliper to rotor. The caliper is designed for a rotor of 140mm radius, so using them on a 324mm rotor with a radius of 162mm means that the caliper offset is not simply 22mm. If you measure up the adaptor its not simply an offet 22mm adaptor, going to 340 is only going to mean the caliper rides higher up on the rotor as the calipers internal radius has to be compensated. I would be surprised if you measured up your adaptor that it has 30mm offset holes?

Sorry, I am not sure that I understand what you are trying to say. On the calliper adaptor, measuring the distance between the inside holes (that bolt to the upright) and the outside holes (that bolt to the calliper) is 30 mm, hole centre to hole centre. So the calliper is moved outwards (from the centre) by 30 mm, since everyone talks about diameter (not radius) that means a 60 mm increase in the rotor dimension. Hence 280 mm to 340 mm.

I did have to remove about ~1 mm by ~2 mm of calliper at the outer extremities of the slot to match the radius of the calliper curve to the radius of the rotor curve. But it was no big deal, a few minutes with the flat file. On a quick comparison the R32GTR calliper (296 mm rotor) and the R32GTST calliper (280 mm rotor) have the same slot radius. So on an R32GTST the calliper slot has a larger radius than it really needs for the standard rotor.

Did that answer the question?

Cheers

Gary

[Roy]

I did have to remove about ~1 mm by ~2 mm of calliper at the outer extremities of the slot to match the radius of the calliper curve to the radius of the rotor curve. But it was no big deal, a few minutes with the flat file. On a quick comparison the R32GTR calliper (296 mm rotor) and the R32GTST calliper (280 mm rotor) have the same slot radius. So on an R32GTST the calliper slot has a larger radius than it really needs for the standard rotor.

Ok, thought that may be the case, you have to either grind the caliper a little or simply space it further out then the 30mm radius of the adaptor.

Sorry, i know this might be the viable option for you....but it isnt for me. Grinding calipers, machining expensive to the rest of us rotors, and then go talk to DBA about your suggestion to duct brakes. Well...

I detailed to DBA the ducting i ran and they flat out said that was the reason the rotor cracked. Inside of the rotor being cooled more the outer face and i SHOULD NOT DUCT AIR to the rotors. So off with the ducting, even though i thought it was a pipss poor escuse for failing and give another set a go and they soon crack as well, at the Dutton Rally of all places.

And that was with about 4,000kms of spirited driving, progressively harder and harder and bedding brakes to make sure that the rotors were nicely cycled. Brand loyalty? I am loyal to good products or at least products that are supported well. The rotors on my car are the ones i replaced at the Dutton Rally and effectively giving them to the purchaser of my F40s as whilst they are near new, i simply dont have any faith in them and dont have the heart to charge good money for them.

So i did casually observe what the professionals do. Cruising around as a scrutineer and a pit moneky at State Rounds i do observe what those smarter then me are doing. Simple fact is DBA 4000 rotors are crap and should not be used at the track if you have any desire for reliable service. The DBA 5000 are another story, far more expensive and i often wonder if the only difference is in the slot deisgn, not metallurgy or heat treatment ?

So suggesting brand loyalty to me re DBA makes me angry Also the fact that i am Joe Blow off the street so they dont give a stuff about me being happy or otherwise. Your involvement in motorpsort circles may afford you slightly different treatment.

They sure were not willing to help out with discounted rotors after the failing of my two sets in quick succession, or even a revised theory when the second set without ducting failed. They then said that my perfect condition calipers were to blame for dragging pistons/pads. I pointed out that they were recently reconditioned and when changing pads could be see to easily move freely. They then said that it was the fact that i had offset caliper mounts and they were the problem, despite the fact that i had years of service from my older desigg DBA 4000 rotors.

LOL, i dont feel any better despite my above purge

Looking at the BSM cars they are all running AP setups with rotors around the 343-355mm mark. I assume they had good reason to upgrade from teh Nissan Brembo GTR caliper and 324mm rotor thati once read was run on the Production Car?!?!?!

I agree that the 324mm adaptor setup is a good budget upgrade, i have been happy with mine. Stopping distances are one thing, fade resistance is another, and pedal feel another again. I just want a setup that is more consistant with better feel and has a little more fade resistance. LOL, most of all i want to run a rotor that i am comfortable will see me through a day of track work

[Duncan]

like bezerk32 said above...I don't know why you guys want to go past the G4 brakes. Well tested, light caliper with good wheel clearance, come as a complete new set with lines, brakes and pads.

I just use the supplied pads, and found them fine, but they take the same pads as the AP caliper Gary posted.

And you will get easy local availability of parts now so many have been sold.

All these other options are head towards twice the price, and in fact the G4s are cheaper than buying GTR brembos (2nd hand un-rebuilt), dba5000 discs, race pads and new braided lines.

So....why look at the expensive kits instead...Is it just simple anti-china bias? The same attitude that we as a country had about japanese cars when they arrived? A caliper and a bracket are a simple thing, easy for a factory with only a little expertise to copy/produce.

BTW Roy I am with you....DBA may deny it all they like but their skyline rotors in the last 2-3 years have had serious problems. And I don't have a lot of respect for companies that deny issues and blame, blame, blame in the face of strong evidence to the contrary. Prior to this DBA were fine, and in fact I still have unslotted, heat treated da4000 on my race car, I think there was either an accidental or deliberate change in the material or design for the newer batches of discs. And Gary, IPRA may be different but DBA haven't paid SSRA for over 12 months for their sponsorship....very poor form to rip off a club when the members are holding up their side of the deal.

[Roy]

How much are the G4 replacement rotors? But the main reason i have not seruiousy considered them is the fact that they are 8 piston calipers. May sound silly, but i am waiting for people using them to tell me that when they are onto their 3rd set of pads whether they are having problems pushing the pistons back, seals have deteriotated with heat etc etc. So many small pistons may mean you have similar piston area for balance issues, but it also means you have way more circumference which means more seals and dust boots exposed and succeptible to heat damage, The fact that the pistons are so much smaller then they woudl quickly heat up as they have less intertia/sooling so possibly damage the their smaller rubber/seals quicker ????

I personally would be far happier with them if they were just 6 piston.

Then there is the colour, a small thing and lastly there is that part of me that doesnt like them because of what they are Though the more i read of Targa cars surviving with them etc is slowly bringing me to the partys

But back to the Stoptechs, they have a pretty good track record in road racing, various lcower tier classes of motorsport in US, they happily pit their kits against Brembo/Alcon etc in brake shootouts for US magazines. They are well supported and have seemed to been a good thing since i first read of them in 2002. So now that the dollar has come to us, i am thinkings its time to try them. Unlike others i like the fact that they are only 4 piston calipers and share pad sizes with Brembo.

Anyway, time will tell. Mind you unless i can flog the Greddys i wont be buying the Stoptechs.

[STR8E180]

Then there is the colour, a small thing and lastly there is that part of me that doesnt like them because of what they are Though the more i read of Targa cars surviving with them etc is slowly bringing me to the partys .

well K sport sell the same brakes but in a different colour?

[phunky_monkey]

Hey Duncan, I have pretty much the same reasons as Troy as to why I'm giving the G4/Ksport/D2 brakes a miss and going for the stoptechs.

I'm not doubting that they're a good product, I just feel that the Stoptechs are better for not much more money if you buy from the right places.

Troy: Heard back from Stoptech, the silver paint will go a yellowy gold colour with extreme heat, so black calipers are the go.

[Roy]

Yeh, if you lo0ok at Jack's Alcons the fronts are a different colour to the rears because of the same thing. Black is more stealthy too, i can throw a Nissan logo on them and people wont think it has brakes

[Sydneykid]

The ducting (on the R32GTST) and the scoops (on the R33GTST) point at the centre of the rotor, not the inner face. It's not as "nice" a set up as the V8SuperCars, but I did test it with the dyno room fan and smoke trace. I made some small adjustments to make sure as much airflow as possible went to the innermost inlet of the rotor vanes. It's not perfect, but it seems effective. I have tried temperature sensitive paint on the inner and outer edges of the rotors and there is no difference in temperature, well not that the paint can distinguish anyway.

Wherever possible I put the race car rotors on one of the road cars for a couple of weeks to make sure any stresses from the manufacturing/machining processes are relieved. I found that method to be effective on the Production Cars back in the early 90's for the 6 hour and 12 hour races. We even ran in a set in driving to Bathurst one year.

I don't class a minute or two with a flat file as "machining", it's not like I used the lathe or the mill or even anything electrically powered. Quicker and easier than cleaning your teeth. If someone told me that they weren't capable of that simple a filing job, then I sure as helll wouldn't trust them to bolt on a set of brand new rotors, pads, callipers and braided lines.

A test that may be useful, one that I have used many times over the years when picking callipers because I couldn't afford to buy band name race items. Measure across the width of the calliper with a good set of verniers. Stick someone in the car to push on the brake pedal with both feet, engine running if it has a power booster. Then measure the expanded width of the calliper. Some very well known brand names show alarming amounts of calliper spread. As Roy mentioned in a previous post, calliper rigidity is a major determiner of brake feel, which facilitates the drivers ability to modulate the brake pressure and avoid lock up. The best calliper that I have tested, using this method, by far is the AP RadiCalliper on the F3.

The problem is spending large sums of money on rigid callipers is pretty much a waste of time if you are leaving the power booster and the ABS. They mask the feel far more than any calliper flex ever will. People are kidding themselves if they think spending $thousands on callipers is going to improve the brake modulation whilever the true weak links in the feel chain, the master cylinder and the ABS, are still in use.

Cheers

Gary

[260DET]

S14 Stoptech big brake kit, Enkei 17" wheel just clears the inner part of the rim, outer clearance from the spokes is fine. Caliper takes common sized Porsche pads.

Edited August 5, 2008 by 260DET

[phunky_monkey]

Thanks for that. I take it that's the 240SX 332mm kit?

[Roy]

S14 Stoptech big brake kit, Enkei 17" wheel just clears the inner part of the rim, outer clearance from the spokes is fine. Caliper takes common sized Porsche pads.

I will onw RP-F1s soon, they are my favourite wheel What width and offset are the Enkeis, and as per Phunky, i assume they are 332mm not 355mm

[260DET]

Yeh, 332mm rotors, nice kit.

Got the Enkeis from the US because Enkei in Oz only sell gay narrow wheels, check out the Enkei US website for the sizes available there.

[Roy]

I know the sizes i want, front 17 x 8.5 +30, though i am not sure how they work with brake calipers ?!?!?!?

[phunky_monkey]

Thanks mate.

Do you know what piston sizes they run? I'm planning on ordering this week, but can't decide between the 300ZX kit or the 240SX kit... need to know the piston size differences first

[phunky_monkey]

Oh, and what car are they on, an S14 or Z? and what rear calipers are you running?

Thanks!

[Roy]

...and who is your daddy and what does he do?

[phunky_monkey]

It's not a tuma