brake bias valve..

[Kozy]

Joe what rear disc swap do you have? These calipers On 282mm discs might be ok bias wise with the 240mm setup (still require nearly double the pedal force to lock up though) but the 260mm set as I suspect you have is dangerously rear biased.

 

[stevenEK9]

WRT to servos: Do you know if you can change servos only? So run 15/16 MC on the EK9 servo or visa versa?

limiting factor would be the adjustability of the push rod that joins to the brake pedal and how much room there is to correct for the difference in servo depth

be interesting to see how the servo size differs, if at all, between 98 and 96 spec integras with the different 1" and 15/16" MC..........

 

[Kozy]

Hmm. It would be an interesting thing to look at when running big brakes as you need far less assistance than the stock setup! Shame Lings doesn't do JDM models to compare the diaphragm sizes on the DC2s.

Out of interest Steven, any idea on the piston sizes in those Brembos of yours?

 

[stevenEK9]

Out of interest Steven, any idea on the piston sizes in those Brembos of yours?

Just got some new seals in the post yesterday for them, will need to check!

 

[joe_thompson]

Joe what rear disc swap do you have? These calipers On 282mm discs might be ok bias wise with the 240mm setup (still require nearly double the pedal force to lock up though) but the 260mm set as I suspect you have is dangerously rear biased.

Im running a 240mm set up of a eg5, I did some testing last night, the backs defiantly lock up first but it is quite hard to get them to, i need to apply quite abit of pressure to do soo.

Iv got some spare 4 pots wiv 37mm pistons off the front of a 300zx, i may now use

 

[Kozy]

Im running a 240mm set up of a eg5, I did some testing last night, the backs defiantly lock up first but it is quite hard to get them to, i need to apply quite abit of pressure to do soo.

Sounds like it's definitely the size of the front calipers to blame. Swap them out and chalk it up as a lesson learned, not all four pots are powerful!

Iv got some spare 4 pots wiv 37mm pistons off the front of a 300zx, i may now use

They're an improvement, but still smaller than the stock 262mm calipers in terms of piston area. Coupled with a 282mm disc, you'll only see a marginal increase in power over a stock 262mm setup, which would be vastly easier to install.

In all honesty, if you are chasing performance then I would just forget about 4 pots unless you can afford a set of Willwoods or better. Grafting on brakes from another model like this seldom yields a proper improvement in braking as is it hard to get everything balanced properly, especially considering the work involved. You'd be better off going for a full 282/260mm setup, it's a powerful proven setup, designed for our cars. It's just not very flash.

 

[joe_thompson]

Sounds like it's definitely the size of the front calipers to blame. Swap them out and chalk it up as a lesson learned, not all four pots are powerful!



They're an improvement, but still smaller than the stock 262mm calipers in terms of piston area. Coupled with a 282mm disc, you'll only see a marginal increase in power over a stock 262mm setup, which would be vastly easier to install.

In all honesty, if you are chasing performance then I would just forget about 4 pots unless you can afford a set of Willwoods or better. Grafting on brakes from another model like this seldom yields a proper improvement in braking as is it hard to get everything balanced properly, especially considering the work involved. You'd be better off going for a full 282/260mm setup, it's a powerful proven setup, designed for our cars. It's just not very flash.

Well iv just worked out that a 262 with 54mm piston equates to 4247.984sq mm TPA and the nissian 300zx with 4 38mm ones are 4537.048sq mm so that shows they are lager in TPA than the stock civic ones.

Why would you recommend wilwoods soo much in compassion with the nissian ones made by brembo? (not being arsey just wondering on what you mean )

 

[Kozy]

Only two of the four are used for working out the effective piston area as they apply pressure equally to both sides. The single piston does this also through the sliders so you either use one side of a four pot or double the single pot. Either way, a four pot usually ends up smaller than a single pot. I worked it out with 37mm pistons, with 38s it's pretty much equal with the 262 caliper, 3.53sq.in vs 3.56sq.in on the Civic caliper.

I recommended the Wilwoods because they are a good aftermarket option, they'll be lighter than most OE calipers an do have a much bigger piston area, around 4.80sq.in. That sort of increase is worth doing in terms of performance, an OE four pot off another vehicle will probably not off much benefit over stock other than looking a bit better and maybe wearing the pads a little more even. It's only my opinion, but it's really not worth the hassle. If you wan to do it anyway then thats cool, at least you know the Nissan calipers will actually work!

 

[FreakyParts]

Hi Joe!
The other problems with the Nissan calipers is they're lug mounts and designed for a 30mm thick disc, so they'll be bodged at best.
How did you get the bracket sorted on those calipers, as everytime my enginer looked at him he looked scared!
As said, when you're calculating piston area, you need to calculate 1 side only, whether it be single piston sliding calipers or 4/6/8 pot monsters.
The Wilwood kit we do comes with 44.5mm pistons, so has a larger piston area than the standard EK9 caliper. Plus it's been tried and tested successfully.
The 300zx calipers are also a bit on the large side, so you're going to be increasing unsprung weight, you'll need to allow for extra clearance for the wheels, and if you're fitting a cast 30mm thick disc, you'll notice it through the steering as it will feel heavier.

 

[joe_thompson]

Only two of the four are used for working out the effective piston area as they apply pressure equally to both sides. The single piston does this also through the sliders so you either use one side of a four pot or double the single pot. Either way, a four pot usually ends up smaller than a single pot. I worked it out with 37mm pistons, with 38s it's pretty much equal with the 262 caliper, 3.53sq.in vs 3.56sq.in on the Civic caliper.

I recommended the Wilwoods because they are a good aftermarket option, they'll be lighter than most OE calipers an do have a much bigger piston area, around 4.80sq.in. That sort of increase is worth doing in terms of performance, an OE four pot off another vehicle will probably not off much benefit over stock other than looking a bit better and maybe wearing the pads a little more even. It's only my opinion, but it's really not worth the hassle. If you wan to do it anyway then thats cool, at least you know the Nissan calipers will actually work!

I see what at your saying, Tbh i have a spare set of hubs that i have machined to allow the use of other calipers with a bracket soo its jst a case of making one which isnt to much hassel for me and i enjoy it aswell as it give me experience Also i have to admitt i am doing for looks to apoint.

I havnt looked into willwoods really soo i wasnt aware that they use quite large pistons.

But yee atleast i know the nissan calipers will atually work, i jst never really thought about it with the jag brakes which i really should

 

[joe_thompson]

Hi Joe!
The other problems with the Nissan calipers is they're lug mounts and designed for a 30mm thick disc, so they'll be bodged at best.
How did you get the bracket sorted on those calipers, as everytime my enginer looked at him he looked scared!
As said, when you're calculating piston area, you need to calculate 1 side only, whether it be single piston sliding calipers or 4/6/8 pot monsters.
The Wilwood kit we do comes with 44.5mm pistons, so has a larger piston area than the standard EK9 caliper. Plus it's been tried and tested successfully.
The 300zx calipers are also a bit on the large side, so you're going to be increasing unsprung weight, you'll need to allow for extra clearance for the wheels, and if you're fitting a cast 30mm thick disc, you'll notice it through the steering as it will feel heavier.

Hey,

Well i jst stripped the calipers down and removed all the seals, and welded them up, I managed to get my hands on some free hubs so i machined then to allow a bracket to bolted on and the also fit fine under my wheels (shame there jst no use haha)

Im not to fussed about the extra weight under heavy turning as im running no power steering anyways. Im currently useing some accord disks that are 114.3 which i re drilled

 

[Kozy]

I have to say Joe, I admire your blasé attitude to just getting stuck in and grinding, welding and bolting away at things that really shouldn't go together, even if it turns out the end result isn't what you expected! Bravo!

 

[joe_thompson]

I have to say Joe, I admire your blasé attitude to just getting stuck in and grinding, welding and bolting away at things that really shouldn't go together, even if it turns out the end result isn't what you expected! Bravo!

haha well the way i see it is, i do motorsport engineering at uni so i learn all the theory and do a part time placement in a race team but theres just that im never gona learn unless i have a go. I know theres chances that i will mess up but it just makes me more eager to do it right!

Some people may mock me for my attitude but its the only way some times

You seem like a clever guy and the sensible soo im sure url understand what i mean.


Ow and i was reading a braking thread over on civiclife u were in arguing against all the idiots saying your theory and physics are wrong haha it did make me laugh what they were putting

 

[Kozy]

Haha, I think they missed the point I was trying to make that's all. I think they assumed I was saying all brake upgrades are pointless, when all I stated was that an unbalanced setup will usually increase your stopping distances. They all went quiet in the end, no idea whether they clicked or not...

Fully appreciate your attitude towards it all bud, keep it up! Where are you studying ME?

 

[FreakyParts]

I've just read through that thread, and there's some valid points made for both sides.
One thing I've seen though is Kozy, you're only saying the point of locking up the brakes is limited to the tyre grip on the road.
What you haven't considered is the friction between the disc and the pad. There comes a point with every brake setup where the pad can no longer slow the disc down and it snatches at it, causing the lockup. This can be way before the frictional grip of the tyres is at the limit.
If this is the cause, then a brake upgrade is the way forward. Whether it be a better friction coefficience on the pads or a larger diameter disc, both will allow the pad to slow the disc down more efficiently.
Fitting calipers with more pistons will give a better distribution of force over the pad, which translates into a better pedal feel and more clamping force on the disc.

Just out of interest, when you did your 260>282mm upgrade, did you use the same pads in both setups?

 

[joe_thompson]

ye, i think some of them just wanted to prove you wrong as well even though they couldn't.
Im currently studying at staffs uni, but iv actually just changed over to automotive engineering as started to lean more towards the buiness side of it as well, and it was quite aimed getting you work in a race team, and im not that fussed about that. I want be more of a designer/engineer rather than just part of say a race in the btcc.

 

[stevenEK9]

Out of interest Steven, any idea on the piston sizes in those Brembos of yours?

36mm / 40mm pistons in the brembos, using a 295x28mm disc

 

[Kozy]

One thing I've seen though is Kozy, you're only saying the point of locking up the brakes is limited to the tyre grip on the road.
What you haven't considered is the friction between the disc and the pad. There comes a point with every brake setup where the pad can no longer slow the disc down and it snatches at it, causing the lockup. This can be way before the frictional grip of the tyres is at the limit.

I've seen you mention this before, however I'm unfamiliar with the phenomenon you describe, I haven't really seen it discussed anywhere else. Most texts on brakes dictate the tyre contact patch as the single limiting factor in vehicle stopping distances.

This said, I think I understand the idea you describe, I recall you using a bicycle wheel analogy and trying to stop it spinning from close to the centre, and then again out at the edge, which does make sense. I think what you are describing is a modulation problem, which gets easier to control with uprated brakes which yes, I agree with. However, I never had any problem with my 262s, I had to push very hard and yes they did fade after about 20-30 minutes round Brands Indy, but the power and balance was more than adequate.

This reminds me, you never responded to my claim on the ITR forum...

Just out of interest, when you did your 260>282mm upgrade, did you use the same pads in both setups?

Going up to the 282s produced some weird results although I changed from DS2500 to EBC Yellows at the same time. Not only the obvious bias imbalance causing lock ups and sending the ABS mental, but the fact the car dived so much made for some interesting handling on corner entry. I traced this back to the under worked rear brakes, which were not producing the kind of anti-lift moment designed into the rear suspension for that rate of de-acceleration. Increased dive increased the front camber, which reduced the front brake capacity further, and the lift at the rear caused all kinds of funky, unpredictable geometry changes. It was so obvious I even had a few fellow competitors mention the the car looked 'wrong' and unstable on the brakes.

Although this problem was exacerbated by my preference for soft compliant suspension, (those running standard issue bonebreaker coilovers don't appear to suffer the same problem) it really did make the car noticeably worse to drive IMO, hence why I've now flogged them and gone back to 262s. I would have upgraded the rears and MC to match, but I have little call for the increased heat capacity with the kind of events I do so it was cheaper for me to go back to the stock brakes. Less unsprung/rotating mass too.

iv actually just changed over to automotive engineering as started to lean more towards the buiness side of it as well, and it was quite aimed getting you work in a race team, and im not that fussed about that. I want be more of a designer/engineer rather than just part of say a race in the btcc.

What level are you studying? My course was all design/theory/maths, no hands on stuff unless you wanted to do it for your project.

36mm / 40mm pistons in the brembos, using a 295x28mm disc

Exactly as I expected, the piston size is smaller than stock! the 3.53sq.in on that size disc barely changes the factory bias, it actually appears to be slightly more rear biased if anything, so you are using more of the available grip to slow you down. All the benefits of four pots, none of the downsides, you can tell that's serious race spec stuff for sure! This said, you have changed your prop valve so it's not a completely straightforward comparison...

 

[FreakyParts]

I've seen you mention this before, however I'm unfamiliar with the phenomenon you describe, I haven't really seen it discussed anywhere else. Most texts on brakes dictate the tyre contact patch as the single limiting factor in vehicle stopping distances.

Ok, 2 identical cars.
Both running super soft sticky slicks on a track. Same compound.
One has standard 260mm setup. The second has, for arguments sake, a 4 pot front upgrade, or even a 282mm setup.
Both cars have the same compound pads.

Get the brakes upto the same temperature. The car with the smaller brakes will find they lock the brakes much easier. This isn't the tyre running out of grip, as they're both the same compound. This is the caliper/pad snatching the disc. It gets to a point where the pad cant slow the disc down any more through friction and clamps on instead.
This is usually caused by the lack of modulation. You're applying too much pressure to the pedal because you haven't got enough range of movement in it. Increasing either the diameter of the disc, or the piston size will increase that.
It will however mean you need to change your driving style, as the pedal will now feel completely different. Some people (read customers of mine) have interperated this as a problem with the brakes feeling 'spongy' or needing to be bled more to try and get rid of it. This isn't needed as you've either increased the pedal travel, or by increasing the diameter of the disc you've reduced the amount of force needed at the caliper to obtain the same force.

It can be a bit of a black art getting the setup right for the individual, as some like an over compensated pedal like found in new cars, as they want to stamp on the pedal, let the ABS kick in and do the work for them, so they've just got an on/off pedal.
Others dont realise that doing a brake upgrade doesn't mean the car will stop instantly, they have to learn to brake again in exactly the same way as jumping in a different car with a different manufacturers setup, it takes you a couple of hundred miles to get used to not wanting to either put your face through the windscreen or rear-ending the car in front

However all that said, I 100% agree, a balanced setup will always work better than an overcompensated front/rear setup. This is why I suggest when fitting a bigger front setup, you make sure the rears are doing what they should be, get the calipers serviced, then put some decent pads and discs in there. It's so often overlooked when working with brakes...

With regards to your question on ITRDC2, I've fired off an email to the supplier to see what he suggests for your setup.

 

[FreakyParts]

Oh and going from DS2500s to Yellowstuffs... it's a downgrade rather than an upgrade I really rate the DS pads as a fast road/track pad. I've got them on the MX5 and they're immense... but there's a reason they're 50% more expensive than the EBCs. Saying that, they're nice and cheap in the Wilwoods compared to the OEM calipers!