Brake Pad & Caliper Questions...

[djr81]

Question for those running Brembo's and/or aftermarket brakes on their GT-R's

The stock R32 front pads measure 114mm in length. What size are those to suit the R33's?

Also for anyone having modified their car away from the standard Nissan calipers two questions:

Did you have to make any mods to the master cylinder to compensate for larger/more numerous pistons in the calipers ie to ensure you still had a proper pedal over the range of the brake application.

Did you make any mods to maintain the front/rear brake bias - this is particularly aimed at people who are using a larger front rotor.

[PMATT]

Question for those running Brembo's and/or aftermarket brakes on their GT-R's

The stock R32 front pads measure 114mm in length.  What size are those to suit the R33's?

Also for anyone having modified their car away from the standard Nissan calipers two questions:

Did you have to make any mods to the master cylinder to compensate for larger/more numerous pistons in the calipers ie to ensure you still had a proper pedal over the range of the brake application.

Did you make any mods to maintain the front/rear brake bias - this is particularly aimed at people who are using a larger front rotor.

<{POST_SNAPBACK}>

The brembo calipers take both the same pad r33/r32 the std 4pot skyline caliper is a similar size . If you put the brembo calipers on a car it will depend on the bore size of the master cylinder some skylines have a 1" and some 1 1/16" these may be alright for the conversion.The brake bias should be alright.What pad are you measuring it is actually the piston sizes in the caliper that will make the difference.

Edited January 24, 2006 by PMATT

[djr81]

The brembo calipers take both the same pad r33/r32 the std 4pot skyline caliper is a similar size . If you put the brembo calipers on a car it will depend on the bore size of the master cylinder some skylines have a 1" and some 1 1/16" these may be alright for the conversion.The brake bias should be alright.What pad are you measuring it is actually the piston sizes in the caliper that will make the difference.

<{POST_SNAPBACK}>

The pad I measured was from the R32 GT-R with Nissan calipers - as I said 114mm in length. Most of the aftermarket calipers suit a range of different pad sizes, anywhere from 114 at the lower end to 152mm. I was trying to identify what size pad went with the R33 Brembos so as to make a comparison on braking torque due to the pads rather than due to the rotor size.

"it is actually the piston sizes in the caliper that will make the difference." - hence the question - does the master cylinder need fiddling with when converting, say a six pot caliper?

[Sydneykid]

The pad I measured was from the R32 GT-R with Nissan calipers - as I said 114mm in length.  Most of the aftermarket calipers suit a range of different pad sizes, anywhere from 114 at the lower end to 152mm.  I was trying to identify what size pad went with the R33 Brembos so as to make a comparison on braking torque due to the pads rather than due to the rotor size.

"it is actually the piston sizes in the caliper that will make the difference." - hence the question - does the master cylinder need fiddling with when converting, say a six pot caliper?

<{POST_SNAPBACK}>

If you are not going to change the rear callipers, then you will have an imbalance.

If you are going to run the ABS it will avoid locking issues, but you will still have an imbalance. Hence you won't get the best braking performance, some of the money spent will be wasted.

There is a lot of science (and a bit of art) in working out master cylinder sizes, including the physical leveage and movement ratios (the pivot point on the pedal etc) and hydraulic movement ratios. I know the formulas (the science bit) but I still don't get it right first time on the race cars, there is a lot of driver feel info required (that's the art bit).

cheers

[djr81]

If you are not going to change the rear callipers, then you will have an imbalance.

If you are going to run the ABS it will avoid locking issues, but you will still have an imbalance.  Hence you won't get the best braking performance, some of the money spent will be wasted.

There is a lot of science (and a bit of art) in working out master cylinder sizes, including the physical leveage and movement ratios (the pivot point on the pedal etc) and hydraulic movement ratios.  I know the formulas (the science bit) but I still don't get it right first time on the race cars, there is a lot of driver feel info required (that's the art bit).

cheers

<{POST_SNAPBACK}>

Sounds like a yes to both questions then. It makes sense that increasing the front brake torque without changing the rears will lead to an imbalance. (Pad temperatures aside). It is just that I have seen a number of people offering brackets to allow the front calipers to fit up to a larger rotor & no one has complained about suddenly locking fronts - so I thought it best to ask. In any case the cycle rate of the R32's ABS is so slow that I wouldn't trust it to unlock the brakes in time...

Can I take it then that to accomodate a larger piston area the bore of the master cylinder will have to increase with a proportional increase in pedal pressure?

[sparkmanv11]

Sounds like a yes to both questions then.  It makes sense that increasing the front brake torque without changing the rears will lead to an imbalance. (Pad temperatures aside).  It is just that I have seen a number of people offering brackets to allow the front calipers to fit up to a larger rotor & no one has complained about suddenly locking fronts - so I thought it best to ask.  In any case the cycle rate of the R32's ABS is so slow that I wouldn't trust it to unlock the brakes in time...

Can I take it then that to accomodate a larger piston area the bore of the master cylinder will have to increase with a proportional increase in pedal pressure?

<{POST_SNAPBACK}>

djr81, I just bought and fitted a set of Endless CC-X pads front and rear for my 33GTR. Part number EP290CC-X shown on the box states " will fit (BNR32 V-SPEC), (BCNR33 GTR), (BNR34 V-SPEC) and (BNR34 VSPEC N1). So I can only assume a standard 32GTR has some pad differrence. Backing plate measurent as follows:

Width across the backing plate 117mm measured with calipers.

Hard to get a vertical measurements as there are no parralel edges.

Hope this answers part one of your question.

[djr81]

djr81, I just bought and fitted a set of Endless CC-X pads front and rear for my 33GTR. Part number EP290CC-X shown on the box states " will fit (BNR32 V-SPEC), (BCNR33 GTR), (BNR34 V-SPEC) and  (BNR34 VSPEC N1).  So I can only assume a standard 32GTR has some pad differrence. Backing plate measurent as follows:

Width across the backing plate 117mm measured with calipers.

Hard to get a vertical measurements as there are no parralel edges.

Hope this answers part one of your question.

<{POST_SNAPBACK}>

Cheers for that. What it means is that there is little to no diference in the actual pad sizes between the Brembo calipers & the Nissan versions. The gain in braking performance is mostly due to the increase in rotor size.

The after market vendors usually use the pad length (Eg 114mm, 127mm etc) to help identify the caliper type. They also use the width of the rotor & number of pots as key indicators of the sizing/performance.

As an aside if you buy pads out of Racebrakes half the time they send them out with backing plates off a Supra.

[sparkmanv11]

Cheers for that.  What it means is that there is little to no diference in the actual pad sizes between the Brembo calipers & the Nissan versions.  The gain in braking performance is mostly due to the increase in rotor size.

The after market vendors usually use the pad length (Eg 114mm, 127mm etc) to help identify the caliper type.  They also use the width of the rotor & number of pots as key indicators of the sizing/performance.

As an aside if you buy pads out of Racebrakes half the time they send them out with backing plates off a Supra.

<{POST_SNAPBACK}>

Bought from NENGUN at $505.00 and arrived from Japan in less than a week. I brought my last set from RaceBrakes and cost the above just for the fronts a Ferodo compound. The CC-X's are Track orientated but I can still drive home on. Less dust than the Ferodos.

After a couple of trips to Mallala i am very happy with them and am now considering upgrading to a 6 pot Endless upgrade kit. Race brakes recommended APs and although I have seen them on skylines the Endless rotors and calipers look appear comparable slightly better priced i.e I could get front and rears for the same AP or Brembo 6 pot front only upgrade. The front/rear balance should be evenly matched. Looking at doing the classic Adelaide this year and should have fitted by then.

[djr81]

Bought from NENGUN at $505.00 and arrived from Japan in less than a week. I brought my last set from RaceBrakes and cost the above just for the fronts a Ferodo compound.  The CC-X's are Track orientated but I can still drive home on. Less dust than the Ferodos.

After a couple of trips to Mallala i am very happy with them and am now considering upgrading to a 6 pot Endless upgrade kit. Race brakes recommended APs and although I have seen them on skylines the Endless rotors and calipers look appear comparable slightly better priced i.e I could get front and rears for the same AP or Brembo 6 pot front only upgrade. The front/rear  balance should be evenly matched. Looking at doing the classic Adelaide this year and should have fitted by then.

<{POST_SNAPBACK}>

$500 for fronts & rears is good buying, well done. Do you have a working temp range/friction coefficient?

Good stuff. Please let us know how you get on. I am in the throes of working out which way to jump on a brake upgrade (hence all the stupid questions). Many people over here in WA use the Wilwood calipers, but I am not sure about the lack of dust sealing. Also there are a number of different types/sizes of Brembos being used with various degrees of success. Not sure I have seen a GT-R running Endless over this way. Getting reliable information in WA (let alone country WA) is bloody difficult.

Reading the last issue of Zoom they referred to the Hispec range of calipers which look to be a good thing. Can't comment on pricing however. Not sure why RaceBrakes seem to be pushing AP aswell.

Edited January 24, 2006 by djr81

[sparkmanv11]

$500 for fronts & rears is good buying, well done.  Do you have a working temp range/friction coefficient?

Good stuff.  Please let us know how you get on.  I am in the throes of working out which way to jump on a brake upgrade (hence all the stupid questions).  Many people over here in WA use the Wilwood calipers, but I am not sure about the lack of dust sealing.  Also there are a number of different types/sizes of Brembos being used with various degrees of success.  Not sure I have seen a GT-R running Endless over this way.  Getting reliable information in WA (let alone country WA) is bloody difficult.

Reading the last issue of Zoom they referred to the Hispec range of calipers which look to be a good thing.  Can't comment on pricing however.  Not sure why RaceBrakes seem to be pushing AP aswell.

<{POST_SNAPBACK}>

djr81 have a look here :http://www.centraxauto.com.au/default2.htm

and here http://www.endless-sport.co.jp/eindex.htm,

Supposedly the AP's have the best dust seals and overall durability.

I have seen since Brembo bought AP, V8 supercars running 6 pot Brembos at last years Bathurst and would consider them as they are in keeping with the OEM, However i suspect they would cost 2 arms and 2 legs. The endless gear has been on Racing Skylines and Porsches in Japan since the R33 with race winning results and constant testing. Plus although its half arsed they are Japanese. I have Recaro's and Takata harnesses I at least should consider Endless as brake upgrade, they should fit nicely behind my TE37's.

[djr81]

djr81 have a look here :http://www.centraxauto.com.au/default2.htm

and here http://www.endless-sport.co.jp/eindex.htm,

Supposedly the AP's have the best dust seals and overall durability.

I have seen since Brembo bought AP, V8 supercars running 6 pot Brembos at last years Bathurst and would consider them as they are in keeping with the OEM, However i suspect they would cost 2 arms and 2 legs. The endless gear has been on Racing Skylines and Porsches in Japan since the R33 with race winning results and constant testing. Plus although its half arsed they are Japanese. I have Recaro's and Takata harnesses I at least should consider Endless as brake upgrade, they should fit nicely behind my TE37's.

<{POST_SNAPBACK}>

The following sites have some info on the Wilwood range:

http://www.wilwood.com/Products/001-Calipe...0-SL6/index.asp

and also the Hispec range:

www.hispecmotorsport.co.uk

Brembo stuff is here:

http://www.hrpworld.com/index.cfm?form_pro...&action=product

I couldn't find the pad sizes used by Endless, but if it is race track cred you are after Larry Perkins used to use them at Bathurst to go the whole race without a pad change.

That is pretty much the 4 (5) suppliers that come to mind. I too have a predilection for Japanese gear - it always is supplied with all the bits you need & is engineered beautifully. Just gives the wallet a hell of a pounding at times.

I have formed the opinion that (on 17" rims) the R33 rotors (ie 324mm x 30 front) with either a 4 or 6 pot front caliper and a pad size of 132mm long or larger. This would give braking at about 25% over and above the stock (R32) set up - providing it is matched correctly to the rears. I struggle to generate one gee under brakes - even with the motor doing its best to help. To be honest I am getting sick of being hosed by Westfields and the like. Also I don't want to bolt up all the bling for my engine till I can figure out how to stop it properly.

[Roy]

There is a lot of science (and a bit of art) in working out master cylinder sizes, including the physical leveage and movement ratios (the pivot point on the pedal etc) and hydraulic movement ratios.  I know the formulas (the science bit) but I still don't get it right first time on the race cars, there is a lot of driver feel info required (that's the art bit).

cheers

<{POST_SNAPBACK}>

LOL...that what i was htinking. A larger master cylinder with the same pedal ratio could cause you more problems.

That said, calculate the volume of the total qty of pistons, and that will go a long way to working out if they will work with the std Nissan gear. You will find that the AP CP5555 have a very similar volume to the std 4 pot Nissan Brembos, that another reason why they are a good upgrade.

Basically you want 6 smaller pistons with equal volume to the larger 4 pot pistons. The 6 pistons vs 4 will give you better pad wear and load ditribution over the face of the pad, so less hot spots etc

[Roy]

Oh, and can i ask why you are so concerned about pad size, well not directly anyway? Pad size doesnt affect your ability to stop quicker. The overall load applied tot he rotor will be the same, only there will be more material absorbing the heat/friction. So technically the larger pad will run marginally cooler.

But it doesnt increase the friction as friction is a result of F=uN. so the u= the compund friction coefficient of the pad, and the N is the perpindicular force. This force N is the force you apply by way of pressing the pedal. So you can see that there is no more actual friction between pad and rotor when running a larger pad.

But you do get the benefit of more surface are controlling the heat, which means rotors are less likely to warp, and the pad wont heat up as quickly. Plus better pad wear. But sure, consider pad size as its a good thig. But i wouldnt be using it as my major indicator, perhaps pad availaibility and the range and cost of pads. Another reason why the APs are good as you can get just about any pad you want for them, some liek SCS use a Porsche pad so again pleny of comounds are available

Do plenty of reading, as it is a bit of a science.. LOL, unles syou just copy someone elses setup which you know works well:)

[djr81]

Oh, and can i ask why you are so concerned about pad size? Pad size doesnt affect your ability to stop quicker. The overall load applied tot he rotor will be the same, only there will be more material absorbing the heat/friction. So technically the larger pad will run marginally cooler. 

But it doesnt increase the friction as friction is a result of F=uN. so the u= the compund friction coefficient of the pad, and the N is the perpindicular force. This force N is the force you apply by way of pressing the pedal.  So you can see that there is no more actual friction between pad and rotor when running a larger pad.

But you do get the benefit of more surface are controlling the heat, which means rotors are less likely to warp, and the pad wont heat up as quickly.

Do plenty of reading, as it is a bit of a science.. LOL, unles syou just copy someone elses setup which you know works well:)

<{POST_SNAPBACK}>

Roy, you are right in saying that the relationship between the normal & lateral forces is nominally linear, but this ignores temperature effects. Most pads lose atleast part of their friction coefficient as temps rise, as you say.

Pad size will also affect wear of both the pad & particularly the disc which can become important with the harder pads.

I suppose the point is, if I am going to shell out for en expensive set of new calipers I may aswell try & maximise their performance aswell. From the pricing the differential between the different calipers say 132mm vs 114 is not huge when lost amongst the rest of the cost of the upgrade. Secondly, for a street/track pad I use the RB74's from Racebrakes. There are more aggressive pads out there, but the RB74's are on their limit for what I do. Because I have to drive my car to the track I can't in all good conscience use a pad that doesn't work well from cold. This tends to limit the allowable upside temperatures & therefore lead towards me wanting to use a larger pad.

To illustrate the point - at the end of the third lap of Wanneroo the anchors are going away in no uncertain terms. I have engine upgrades sitting in boxes at home ready to go on, but they will largely be wasted until I can stop the car more consistantly. At the end of the main straight my present terminal velovity is 188km/h - down to a cornering speed of 100km/h. The planned hp will push this over 200. So I have to do something to make the pads work for longer as well as make the car stop better.

As for pedal pressure after the last track day I was carrying a limp (Nigel Mansell style) simply because I was thumping the pedal so hard at the start of the braking areas. I would copy others set ups, but unfortunately the number of GT-R's over here that people are willing to take onto the track is very finite. The number of those with brake upgrades even more so....

[djr81]

LOL...that what i was htinking. A larger master cylinder with the same pedal ratio could cause you more problems.

That said, calculate the volume of the total qty of pistons, and that will go a long way to working out if they will work with the std Nissan gear.  You will find that the AP CP5555 have a very similar volume to the std 4 pot Nissan Brembos, that another reason why they are a good upgrade.

Basically you want 6 smaller pistons with equal volume to the larger 4 pot pistons. The 6 pistons vs 4 will give you better pad wear and load ditribution over the face of the pad, so less hot spots etc

<{POST_SNAPBACK}>

Good point. Can you confirm what the piston volumes are for the front & rears?

[Roy]

Sorry, i have a spreadsheet at home with all the Nissan caliper sizes and master cylinder sizes, rotor sizes etc, but am working in Singapore at the moment

But if you do a search you will find the piston sizes, as i have posted them before.

You may find it worthwhile before doing anything; to at the next track day, paint your rotors with some temperature indicating paint, and find out just how hot they are running.

Have a look at the rotor temp, and just check that there isn’t a pad that has good cold performance whilst still having sufficient high temp performance. I love RB74s, but did notice they were getting stressed at Sandown. A compound change can work wonders. Next time at Sandown I ran Comp 9 fronts from Race Brakes and the car pulled up no problem all day. And Sandown has a few big stops, but also some big straight to help get them cool down.

I agree that whilst you are upgrading, may as well consider the niceties as well, but also look at pad price, availability and range of compounds. I have from time to time been able to buy some race calipers real cheap. But the price of the pad, and the available compounds meant that i would have had to get custom backing plates cut with a street compound bonded to them. That’s an extreme case, but they were 8 pot Brembo’s off an Indycar

So, not saying you don’t need to upgrade, as I love big brakes…but that said id rather spend $3,000 on driving my car at the track, rather then spending it on brake upgrade which I may be able to avoid through a pad//fluid change and a change to driving style.

Regarding Waneroo, wiping off 100km/h once every 80 seconds shouldn’t be too demanding. The stop at the end of pit straight looks pretty big as well, what is it, 140 to 70km/h? Then the stop at the right hand loop down hill. Actually, I would think that would be the hardest stop as its down hill, the final corner on the back straight, isn’t that uphill?

Be interesting to see what you end up doing and what improvements you notice.

[djr81]

Sorry, i have a spreadsheet at home with all the Nissan caliper sizes and master cylinder sizes, rotor sizes etc, but am working in Singapore at the moment

But if you do a search you will find the piston sizes, as i have posted them before.

You may find it worthwhile before doing anything; to at the next track day, paint your rotors with some temperature indicating paint, and find out just how hot they are running. 

Have a look at the rotor temp, and just check that there isn’t a pad that has good cold performance whilst still having sufficient high temp performance.  I love RB74s, but did notice they were getting stressed at Sandown. A compound change can work wonders.  Next time at Sandown I ran Comp 9 fronts from Race Brakes and the car pulled up no problem all day. And Sandown has a few big stops, but also some big straight to help get them cool down.

I agree that whilst you are upgrading, may as well consider the niceties as well, but also look at pad price, availability and range of compounds.  I have from time to time been able to buy some race calipers real cheap. But the price of the pad, and the available compounds meant that i would have had to get custom backing plates cut with a street compound bonded to them.  That’s an extreme case, but they were 8 pot Brembo’s off an Indycar

So, not saying you don’t need to upgrade, as I love big brakes…but that said id rather spend $3,000 on driving my car at the track, rather then spending it on brake upgrade which I may be able to avoid through a pad//fluid change and a change to driving style.

Regarding Waneroo, wiping off 100km/h once every 80 seconds shouldn’t be too demanding. The stop at the end of pit straight looks pretty big as well, what is it, 140 to 70km/h?  Then the stop at the right hand loop down hill.  Actually, I would think that would be the hardest stop as its down hill, the final corner on the back straight, isn’t that uphill?

Be interesting to see what you end up doing and what improvements you notice.

<{POST_SNAPBACK}>

I have the DBA 4000 series rotors which had the thermographic paint on the rotors. I say had because all three colours have flashed off.

Funny you should mention the 8 pot Indycar Brembo's. One of the few Gt-R's over this way with an upgrade is running them.

A lap of Wanneroo (68 seconds for me at the moment) has three big stops. The one you mentioned is the first and is from 165km/h to 100km/h before CAT corner. Unfortunately it is one 10 or 15 seconds after the stop at the end of the main straight from 188 to 100km/h. Into Kolb (Great corner) is from about 170 down to 110 or so. Plenty opportunity to get some serious heat into the rotors.

Here is one I prepared earlier - notice the build up of carbon in the grooves & also the white thermographic paint on the rotor edge.

Edited January 25, 2006 by djr81

[sparkmanv11]

The following sites have some info on the Wilwood range:

http://www.wilwood.com/Products/001-Calipe...0-SL6/index.asp

and also the Hispec range:

www.hispecmotorsport.co.uk

Brembo stuff is here:

http://www.hrpworld.com/index.cfm?form_pro...&action=product

I couldn't find the pad sizes used by Endless, but if it is race track cred you are after Larry Perkins used to use them at Bathurst to go the whole race without a pad change.

That is pretty much the 4 (5) suppliers that come to mind.  I too have a predilection for Japanese gear - it always is supplied with all the bits you need & is engineered beautifully.  Just gives the wallet a hell of a pounding at times.

I have formed the opinion that (on 17" rims) the R33 rotors (ie 324mm x 30 front) with either a 4 or 6 pot front caliper and a pad size of 132mm long or larger.  This would give braking at about 25% over and above the stock (R32) set up - providing it is matched correctly to the rears.  I struggle to generate one gee under brakes - even with the motor doing its best to help.  To be honest I am getting sick of being hosed by Westfields and the like.  Also I don't want to bolt up all the bling for my engine till I can figure out how to stop it properly.

<{POST_SNAPBACK}>

djr81, was told by Howard at RaceBrakes to accomodate the 6 pot AP calipers on a standard R33 rotor I would need to go to an 18" rim. I would assume this would also go any other brand 6 pot. I couldnt get my fingers between the wheel and top of the rotor when I had the OEM 17" rims on with the OEM Brembo 4 pots. I would definately get some size specs before you buy a 6pot brake upgrade pack regardless of brand. Having said that I think you can get 18" rims on a R32 GTR without any scraping issues and the guards would be filled up as well and you are guaranteed the caliper will fit. One word of caution I have heard of large caliper upgrades touching steering componets at agressive camber/castor angles, just something else to check.

Edited January 25, 2006 by sparkmanv11

[djr81]

djr81, was told by Howard at RaceBrakes to accomodate the 6 pot AP calipers on a standard R33 rotor I would need to go to an 18" rim. I would assume this would also go any other brand 6 pot. I couldnt get my fingers between the wheel and top of the rotor when I had the OEM 17" rims on. I would definately get some size specs before you buy a 6pot  brake upgrade pack regardless of brand. Having said that I think you can get 18" rims on a R32 GTR without any scraping issues and the guards would be filled up as well and you are guaranteed the caliper will fit. One word of caution I have heard of large caliper upgrades touching steering componets at agressive camber/castor angles, just something else to check.

<{POST_SNAPBACK}>

Absolutely. I didn't want to go to an eighteens for a couple of reasons:

1. I actually quite like the 17" rims I already have.

2. R compound tyres in 18" are, for me, just too expensive.

May have to talk to Howard - just hope I get him on a good day - he can be a little um, curt when the shop is busy.

[sparkmanv11]

Absolutely.  I didn't want to go to an eighteens for a couple of reasons:

1. I actually quite like the 17" rims I already have.

2. R compound tyres in 18" are, for me, just too expensive.

May have to talk to Howard - just hope I get him on a good day - he can be a little um, curt when the shop is busy.

<{POST_SNAPBACK}>

Just spoke to Steve Cramp MANTA Racing services who has put 6 pot

AP's on 2 Track 32 GTR's. The AP's will fit specific 17" rims, the ones he has done were on the cars had the same set of RAYS on each, maybe that is telling you something, not sure of the style. If you want I can find out may take a day or 2. He tongue in cheek said he would be happy to fit. Clearance was around 4.5mm top of caliper to rim, apparently sufficient.