I'm trying to finish off the last bit of upgrades to my 3.2 conversion car. The stock 914-4 brakes do not have vented rotors in front or back. Since this car is primarily a track tool I want to get some cooling into the rotors. To me attempting to cool a non vented rotor seems like an act of futility given the close clearances between a 15" wheel and the rotor and calipers.

So I'm off running, not even resisting the slippery slope more like diving down it....
This is all going on a 4-bolt/3" caliper mount car...

What I'm looking at is this:
M (48mm) 3" mount bolts front calipers on the front
914-4 (42mm) front calipers on the rear
Front rotors SC 282.5X20
Rear rotors ?? SC 290X20 ??
19mm master cylinder
Mueller 4-bolt front hubs
Wilwood Pressure Relief Valve (knob type)
Tee in place of OE pressure relief valve
Brake cooling ducts in front (exact model undefined)

I'm not so sure about the SC rotors on the rear with a 4 bolt setup. Is this where some thing like the v-caliper conversion comes in?

The way this all shapes up in terms of the brake hydraulics looks like this:
In front I'll be outputting 5% more caliper force per unit of pedal force.
In the rear I'll have 30% more caliper force per unit of pedal force (I do think that these cars are substantially under braked in the rear - people running TEEs with stock brakes would seem to substantiate this).
With the 19mm MC and the proposed calipers I'll have about 14% more pedal travel...if I were to leave the 17mm MC in I'd have more like 30% more pedal travel.

From looking at the numbers this looks like an entirely workable solution that lets me avoid buying a bunch of 5 bolt wheels for a real long time.

What do ya think?

Later,
Kevin

Sounds like a nice start.

The one thing I would change is the thing you question in the end. Moving the fronts back there:




1. You'll need spacers for them. 911 rear m-caliper spacers may work but...
2. I think you'll have a bit more piston than needed.

Dan has done well with this combo on solid rotors in the back but he uses different type pads to get a balanced result.

The V-Caliper is for that early 911 through SC rotor but it doesn't mean 4-lug. You can keep it 4-lug by having that rotor drilled to 4x130.

Here's what I would change in your mix:

* Instead of 914 fronts to the rear I would use 911 Rear M-calipers. (38mm pistons BTW)
* Drill the rear 911 rotors to 4x130.

This will give you a good balanced mix of factory M-Calipers on your car and most importantly, you will get vented rotors all the way around for the track. The 19mm is perfect for the application.

Let me know if you need the rear M-Calipers. We have a couple pair in-house now

If you already put a 3.2 in it, why don't you go 5 lug and be able to use any brakes you want? It opens up a lot more choices and lets you use some real brakes. Why skimp now?

Also, you can cool solid rotors. There are a couple of way. The nicest I've seen is CFR's (Racer Chris) set up.

Hey Matt:

That's a good question. I'm working with some rules sorrounding race car classification right now. The club I run with (POC) made a couple of landscape changing rule modifications that kick in this season. The first is that narrow body cars, early 911 and 914, running stock bodywork and tire sizes get two points deducted from their classification points. The other is that cars that are over the class minimum weight get points removed at the rate of 1 pt per 35 pounds over. For me this means that if I choose wisely my car will run in a lower class than I'd originally planned if I DON'T do a few things. The first thing I must avoid is to flare the car. The second thing I must avoid is spending a wheel barrow full of money on CF hoods and the like to lighten the car. The third thing is that I need to watch my brake upgrades very carefully. From a competitive standpoint I should be competitive in the lower (V4 rather than V3) class with this car.

So in this scenario, 5 bolt wheels don't buy me anything. Huge brakes, and I've got a set of turbo brakes on the shelf, also aren't going to help a heck of a lot either. I'm looking to, within the class constraints, maximize my heatsink for braking. I'll get the brake system setup and then set the car weight to run as light as possible while staying with the lower (V4) classification.

Sorry for the long post, but I thought you deserved a real answer because it is a very good question.

I've searched all over the place for pictures of brake cooling on solid rotor cars and didn't find Chris' car anywhere. Maybe if he reads this he'll point to some digipix we can have a look at.

Best Regards,
Kevin

Chris must have taken them off his site. I would call / email him. They looked really nice and no one else has anything like them. But, you can make up your own cooling setups.

If your only requirement is to keep stock size wheels and tires, can do that with 5 lug setups and have much better brakes.

Remember, better brakes will make you more confident and let you go deeper. That will allow you to lower lap times.

Also, with a 3.2, you are going wear out pads very quickly. The problem you will run into is not cooling, but rather surface area. I can tell you how to make the brakes not fade, but they will be ridicuously hot. You'll spend a small fortune on pads. I don't know your tracks, but with a healthy 3.2 and a good driver, you are going to average over a set of pads per day. Also, you'll get some really funky brake rotor warping....

What rims are you running cuz with 5 bolt Cookies or Fuchs you can run 7" or 6" rims instead of the 5.5" Fuchs or Mahles..
course you could run some custom size 4 bolts but that ain't stock.

I agree with you Matt about good brakes being a confidence builder. There's nothing better than KNOWING that when you hit the binders they'll work and work well!

I guess I'm not thinking that I'll be underbraked in the proposed setup. The track that I run all the time, Streets of Willow, while being tight, I don't feel is particularly hard on brakes. At WSIR, "the big track" there's only a couple places were you need to touch the brakes and it's not hard braking at that. The other tracks out here are pretty variable with respect to brake use...as they say YMMV..

With respect to pad wear wouldn't that be directly proportional to cooling? I suppose there's a limit to everything it's a matter of whether I reach that limit.

I don't have to keep stock wheel width, but, with a narrow body car...

If I go to 6" wheels (I'll have to pay the price in classification points) they'll be a hyper-light open spoke design...remember when Mueller was purusing wheels? He found all kinds of options.

Later,
Kevin

If actual brake -cooling- is the most important issue, the ducting will make it or break it (no pun intended). Getting fresh air into the wheel housing, and onto the rotor will do more for keeping your brake heat in check than all of the other goodies combined. And without the ducting, chances are all those goodies will only help a little.

Vented rotors are great. No question. But they still need fresh air to work well. The biggest challenge with 914 brakes is not their stopping capacity (they work pretty well in stock form), is that the location and design of the 914 makes for pretty stagnant air up in the front wheel wells. This is the brake killer on these cars. If you can't exchange the air in there, the heat cannot be pulled out of the rotors as effectively, and you cook the brakes. Pretty much any of the after market air dams that have brake ducts built into them will provide you with ample air as long as you can plumb the air to aim onto the brakes. Even innexpensive dryer hose (from Trekkor's sponsor - Home Depot) can do the job (although the end nearest the brakes might melt a little).

Air is the single best thing you can feed your brakes. Then give'em some good pads, and some good fluid, and you're set.

Vented rotors increase your overall thermal mass. But they also increase the avaialble surface area for heat dissapation. They do however, increase your unsprung weight as well. Vented rotors, especially if you go up in diameter, will help you in situations where you have higher sustained brake loads. So you have more headroom (thermally) during any single braking maneuver. But getting air to the brakes will be what allows your brakes to recover down the straights.

So if you run on smaller tracks, or do not anticiapte lots of 120+ mph stops, then even solid rotors can do a pretty darn good job. The 914 is not very heavy, so it doesn't need giant 930 brakes. But with a 3.2, it'll get going quick, and you probably will see higher speeds when braking.

-Josh2

If you look at my pic below you can see its stock fendered with 7" cookies. Don't have to run 5.5" rims....unless its a class rule.

You guys might be interested in the experiment I performed the other day. I was curious how much abuse the stock brakes could take. On my car the stock brakes are in good condition and function just fine. I decided to do some stops from 60 MPH just to see how things would heat up. In groups of six stops, I threshold braked the car from 60 to 5, ran it back to 60...you get the idea. There wasn't much time between each cycle of the brakes, I'd estimate that it was 10 or 15 seconds between braking cycles, for things to cool down. You'll notice that the first rotor temp is high compared the the next reading. I attribute that to using an IR pyrometer. I used a touch probe for all the readings except the first.

I was pretty impressed with the braking performance of the stock system. 30 hard stops from 60 MPH is nothing to sneeze at! This was with old fluid as well so the results might improve marginally with fresh fluid. The only bummer is that I wasn't able to measure braking distance as well on this series of tests.

Later,
Kevin

vented rotors really help on those repeated 120 -20 mph corners...I tried that one track day and after 5 times into that corner my darn near new stock brakes were fading pretty good. So on went vented disc's and the carrera calipers plus I will be installing ducting. I suppose you could install ducting first to see how that cools.

Cool data, I mean HOT data
I've ridden with Trekkor several times AXing, and he has no complaints with stock brakes that are cooled with ducted air in sn AX or on the track. He's running a 2.0 six.... little less there...but for what it is worth I think doing a simple plumbing with some duct work and re-measuring temps would be a good start vs. lots of time and $$$ on a new set-up.

I've gone down this road. You'll get enough cooling to get through a session with stock brakes - the only pads that will work will end up being Raybestos. You'll cook anything else. You'll need two sets of calipers - you'll cook the seals out of the ones on the car after about 8 session and have to rebuild them. You'll go through a set of pads every 4-8 session. I can tell you that is true for every track in the North East. You're brake budget will run somewhere around around $1.50 per minute of driving.

That's a GREAT study!!

I would say the reason you still had brakes durring the test was the pads. I've also done some punnishing brake tests. I did similar 60-5 stop tests with Porterfields (no pyrometer or other data though), and still had plenty of brake left even with smoke pouring from the wheel wells. And the pedal collapse you had is possibly due to the Castrol LMA fluid. LMA has boiling points of 311/446 degrees. The wet point (lower number) is a little better than some of the fluids, but the dry boiling point is quite low compared to pretty much any other fluid in the game. One of our stewards put together a table for our TT program on fluids, here's a look at a bunch of different fluids, and their specs.

Castrol SRF: 518/590
Ate Super Blue: 382/536
AP-600: 410/590
AP-550: 284/550
Wilwood EXP: 417/600
Wilwood 570: 284/570
Performance Friction Z-Rated: 284/550
Ford Heavy Duty: 284/550
Castrol LMA: 311/446
Motul 600: 421/600

I'd say the loss of the pedal was due to boiling of the fluid. LMA has a pretty low wet boiling point compared to others, and I'd say that although your caliper temps when checked were below that, letting it sit for any time with the rotors that hot (1000 degrees is glowing deep red) heat soaked the system. The backing plates of the Porterfields can insualte pretty well, but there are limits to what just the pads can do. And with old fluid that's already sub-optimal even when fresh and dry, I'd say that was a big contributor to your fade.

My prefered fluid is Motul or AP. I'm willing to pay the premium. I view the brakes as my life-line. Loose your brakes, and you could loose your... well, you know...

I'd really love to see that study done again, once with ducting and once without. I think you'll find the ducted temps will be a good deal lower. It would be really neat to try and include braking distances too if you can. If you do that test, I'd love to be able to use that data on our TT website for new drivers. Could I?

Colroado Region TT series brakes info page.

-Josh2

Having both stock 4 lugs and now 5 lugs with SC rotors I can definitely feel the difference on track and my car only makes 165 HP. I think for T4 and lower HP sixes that the stock 914-4 brakes are fine. With a 3.2 and plans to go to the track I would want more braking effeciency than the stock 914-4 calipers and rotors can muster.

I can attack corners with a lot more confidence with current SC vented brake setup. I dont think I'd want to see what would happend with stock 914-4 brakes if I used them as aggressively as the vented SC rotors I have now. As you get faster with a high HP car your hauling car down from very high speeds which generates a whole lot of heat. After a hard 25 min track session in my car I start to feel a little fade.

$1.5/minute!! Yikes. I don't know the east coast tracks at all but they must be bloody severe! These California tracks in general just aren't going to cook brakes like that. My 60->5 brake test is probably more extreme than a 20 minute session at WSIR. At WSIR it'll be (estimating since I haven't driven this car there yet) 140MPH->100MPH, 100MPH->40MPH, 70MPH->40MPH all in a minute and a half or so per lap. It's just not THAT hard on brakes.

Later,
Kevin

930 calipers fit under 15" wheels

Hey Josh2 -

I am planning to re-run the brake experiment with fresh fluid and ducting. The plan is to have a look at the effects of ducting air to the calipers and rotors, looking for the optimum solution without making my money hemorage (sometimes referred to as "the '14") much worse than it already is. I've been running Castrol LMA for a while now and found it to be pretty okay. I'm going to switch to Ford hi-performance when I bleed next to give it a try. I don't mind bleeding the brakes frequently...

If you want to use my data on your website I don't mind. Just give credit were credit is due...

Later,
Kevin

Awesome! Can't wait to see your data!



Definitely bleed the brakes often with the Ford stuff. Because of the lowered wet boiling point of the Ford fluid, you really want to be sure that you have dry fluid in the system before you punnish it (testing or track driving). The advantage with the Ford stuff is that it's pretty cheap, and you can it at nearly every Ford dealership. So you can afford to flush the brakes often with it.



And you'll get it! Thanks!!

-Josh2

Hey Kevin,

That is severe enough you will have problems. You won't disapate enough heat in a lap. After about 15 minutes you'll start having trouble....

You can try it, but you will have trouble. There are lots of options for brakes, including (gast!) things not Porsche (OH NO!) that will work better (must be blasphemy).

As for fluid, if you want good cheap stuff, skip the ford and get the Valvoline Supersyn.

Hmm Eric. Being overbraked in the rear is something I don't want.

So I looked over the numbers again this evening. I reckon the number to really look at are the "regulated press. ratio F/R" You can see that with stock 914-4 brakes the pressure ratio (unit pressure of one front caliper to one rear caliper) is 3.60. With my original (M front on the front, -4 frts on the rear) proposal I'd be at a F/R pressure ratio of 3.04 meaning that I'd have more back brake than stock after maximum regulation through the Wilwood valve. What you suggest brings the F/R pressure ratio into something that could be adjusted to the stock F/R ratio if needed with regulation through the Wilwood valve. I don't know the area of 914-4 caliper pads so I haven't incorporated that into the calculation...they are smaller than M caliper pads I assume. What all this tells me is that I won't be able to adjust enough to get to a stock F/R balance assuming that's what I'd want with my proposed setup.

Running differing pads F/R is not something I'm at all interested in doing. I may move forward with the -4 calipers in the rear, since it won't cost me anything except a little test time. It'll allow me to explore that idea that the rear of the 914-4 is underbraked in any case.

Is Dan running a regulating valve on the rear brakes?

Regards,
Kevin

Click to view attachment

the front 4s on the rear work fine. I use Porterfield R4Es upfront and aggressive street pads in the rears...works great and pad wear is very acceptable front and rear. the 4 fronts might not be ideal but they were "free" and are working for the time being. I might consider moving to vented rear rotors and M rears next off season....busy with motor build right now and my brakes are working fine presently.
Pad sizes for an M caliper and the stock 4 fronts are the same it is the vented rotor and larger piston size on the M that makes the difference.
I know using different pad compounds doesn't sound too appealing but it does work and it isn't that big of a deal With your adjustable valve you shouldn't even need to use different pad materials.

That's interesting Dan. Why did you decide to forego the valve for the rears? Does this mean you are running a TEE in the OE valve's place?

Regards,
Kevin

yep I have a T instead of the P valve. I didn't use a valve because it adds points in our rules system...decided to try to balance the braking with pads and was able to accomplish this. I kept all the stock parts including the P valve and the rear brakes so if my experiment didn't work I could have went back to the original setup on the rear. I also wanted to eliminate the need for setting airgap on the rears. Now I just throw in the pads front and rear and away I go...no adjusters
Not something I would suggest for novice AXers or DE/TTers but I was confident I could come up with a satisfactory combination.
I did and am quite happy with the results and am in no hurry to modify my brake system any further with my current power plant.

Well thought out, well said.

Correct. The castings on these calipers are almost identical. The 911 "rear" M-caliper (so as not to confuse) has 10mm spacers for the vented rotor Kevin wanted to run and the same 38mm pistons used on the 914-6, 914-6/GT, 911 through 1984, early 930 etc... Again, that's my recommendation based upon the criteria in the first post.





...and your vented rotors unless you throw some Rear M-Caliper Spacers in there.

For those of you looking at this option with the solid rotors in the rear, I recommend the 911 Rear M-Caliper with the spacers taken out. That's almost identical to what Dan has done on his car and you should be able to match the pads/system a tad bit easier. I would even go so far as to leave the factory P-Valve in (it is adjustable). Your car won't know the difference between a stock 914-6 brake set-up and this. Another small benefit is the fluid inlet is on the side and doesn't require a banjo. Simply swap the factory hard lines from left to right.

***MY ATTORNEY (Esq. Cap'n Krusty) SAID TO MAKE SURE I MENTION THAT THIS IS FOR A TRACK VEHICLE ONLY. DO THIS TO YOUR STREET CAR AND YOU WILL PROBABLY DIE SOME DAY (pretty safe assumption)

Guys, remember he is talking about a car with a 3.2 in it. That is much faster than a stock 2 liter. Sure, stock brakes or M calipers will work on a stock motored car, but his will be far from that.

To each their own, but that will not be a fun car if driven anywhere near the limit. I'm not sure if it counts as a swear over here, but Brad has said the same thing in old posts. Experience teaches.

I have a different recommendation for that altogether, especially on the track but, I was going off his original post.

For his car I would flat out recommend:

A or S-Calipers up front and,
911 Rear M-Calipers.
Vented rotors all around.

5-lug as you mentioned earlier. But, I don't think that's where he wants to go right now.

Eric,

I thought it was your job to keep things in line around here!
These brake threads get my heart fluid boiling every time.

I have to throw my thoughts out there.
I don't think that a 3.2 914/6 has to be that much heavier or faster than alot of small bore 914/6 cars.

I think that the fact that its a 3.2 at roughly 220hp doesn't change things from other 220hp 914's

I don't automatically think that you have to have rear vented rotors.
I disagree that the car will stop better if you do have huge brakes on it.
I feel that pad compound and tire compound have more to do with stopping.
I feel that that bias ratios and master cylinder ratios have more to do with the "feeling" of the set up than do HUGE calipers

I know many porsche race cars not running rear vented rotors with 200hp.
I personally only run about 170hp on my non vented rear rotors, but I have NEVER had rear boiling problems.

my old race car did have unnecessary rear vented rotors.
talk about weight
your adding 20lbs of unsprung weight instantly.

there are situations where rear vented rotors are necessary.
but the HP and gearing, as well as track layout and amount of cooling air can certainly play into that decision.

I feel like I have actual experience on this issue from both perspectives and I only want to point out that bigger, or biggest is not always mandatory.

certainly eric has seen some first hand views of 914/6 race cars with an equal 220hp that did not need rear vented rotors and would not be any faster or "feel" any better wtih said rear rotors.

brant

Calma Tia, Calma...

"All" the HSR cars I've seen have S-Calipers up front and 911 Rear M-Calipers or 914-6/GT calipers out back. They are about as fast and as demanding as I would expect to see from a 914 chassis.

Vented rotors do not add 20lbs. Eating like "you do" adds 20lbs!

Otherwise I agree with Aunt Brant, BUT... if it were my car and I was going up against Bill Lewis Jr. in his 2.5 -6, I'd have S-Calipers up front and rear 911 M's or GT's all on vented rotors (wait... that's what's on my car)

(plus... you drive "really" slow)

Woohooo! Just ordered up some AJ under the a-arm mount brake cooling ducts.

All my dreams will now come true...

Eric,

its been 3 years since I weighed rotors side by side.
so being that your the brake expert....


post the actual weights for me of a non vented rear rotor
versus
a vented rear rotor (SC type or any type is fine)


Kevin, those cooling kits are great
they don't take too kindly to off track stuff, but other than that they rock.
we have been running them since about 1996 with fabulous results.

(and p.s. there is a home depot version that I also use... (I carry spares) its one that trekkor hasn't figured out yet... so keep it on the down low)

brant

/4 and /6 rear rotors weigh slightly different please specify

not really...
maybe the difference of 1 bolt hole's weight

911 rear rotors on the other hand have a ton of weight in their casting for the rear parking drum... an unfortunate thing since race cars don't really need parking brakes.

homogenious material, Diameters are different.. and one has an extra hole in it

It'll be a while honey. I have the -4 and -6 rotors here but the vented are on my car with wheels and lug nuts and all sorts of stuff I don't want to mess with right now.

Kevin; a few thoughts from a fellow POC guy. I don't see how you are going to get your 3.2 into V4. You have 12 stock base points and have to take the full 13 prepared points. Your engine is costing you 21 V points, so without any other V points against you and deducting the -2 for stock body you would be at 44 points. You'd need to save 5 points to get into V4 which translates into being 175 lbs. overweight.
Here's a pic of the air scoops I use on my car.

Hey drew365! You're pretty close in you're analysis...I'm asking for a call on my base points from the comp director though. It's a '72 1.7, that's class A, zero base points. Taking base points for an exact equivalent of a 914-6 (class G) doesn't make sense unless I get to recalculate the V mods based on the theoretical 914-6 that I never built. It'll probably be a mess but that's what I going after. Oh, the car is FAT, but I can't afford to put it on a diet just yet.

Thanks for the brake ducting digipic. So is the hose from the duct missing in the digipic?

Later,
Kevin

Chris Campbell might be able to answer if you can get away with 0 base points. He's in V4 with a 2.4 conversion. I thought that once you went to a six you took the points and could use 5 lug and -6 stock brakes. I could be wrong.

"So is the hose from the duct missing in the digipic?"

No hose, no duct. It's just a curved piece of stiff plastic bolted to the suspension. It diverts air towards the rotor without taking up much space or worrying about where to run the hose.

I'll just throw in my $0.02.

On our 3.2 track car, we used to run 911sc calipers in front, and front 914 calipers in the rear (solid rear rotors). This gave us the same PAD SIZE as a 911 SC. We used the same compound pads front and rear.

Through experimentation, we came up with a setting for our adjustable proportioning valve that worked to lock the front brakes before the rear brakes consistantly. The proportioning valve was nearly closed (little pressure to rears).

Fast forward to a year two ago, we went to 930 brakes in front with the front 914 calipers in the rear (still solid). We went with a 23mm master cylinder due to extra volume with the 4 piston 930 front brakes.

We were able to open the adjustable prop valve slightly (1/4-1/2 turn), but it was still mostly closed. If we opened this any more, we were risking locking the rear wheels under threshold braking. (Remember the weight transfer under heavy braking)

After studying the different piston sizes (and warping solid rear rotors), we are switching the 914-front calipers to rear 911 "M" calipers and vented rotors. This should allow the proprotioning valve to be opened (maybe full open) and still use the same size rear pads. Hopefully, the vented rear rotors will dissipate heat better and warp less.

To sum it all up, I feel that the 914 front calipers have too much piston for the rear.

Again, just my $0.02

ok...
then take a guess for me at what the weight difference is...
(like I said, once upon I actually weighed them, but now have forgotten the #s)

1837 wet and metal baby...
I may be fat, but my cars not.

brant fat? he looked like 140 soaking wet LOL

brant.. you gain some 'mass'?

Hey John. Thanks for the description. Back when you were running SC pads in front what kind of pads where you running and how did you feel about the wear?

I don't mean to drag you into this mess, but if you were able to adjust the prop. valve such that the 914 front calipers, located on rear, didn't lock at the wrong time why do you feel there's an issue? I would be concerned with the change to M rear calipers that if the valve were set wide open that I wouldn't be getting as much braking as possible out of the rear brakes.

Regards,
Kevin

Here are the shipping weights from my supplier:

914-6 Rear 11.46 #
914-4 Rear 9.86 #
SC Rear 13.6#

I haven't checked them, but I would believe they are correct if this is what they base their shipping charges on.

cool thanks Matt,

why are the stock -4 and stock -6 different from each other.
the diameter is nearly a wash, and one extra bolt hole shouldn't make much difference either.

brant

oh...
one more thing

Kevin, regarding the brake cooling kit.
if you didn't already buy them..

make up some blocking plates for the outside of the hub
they are really easy to make yourself if you want to save the $$$ of buying them. But either way, you need to have them!
they force all of the cooling air to go through the rotor, and not escape out of the hub before its done any cooling. they really should come with the kit, because they are mandatory.

also, your going to want to install screens on them.
I used stainless steel wire for my screens.
you can run without screens, but you will find the vent slots on your rotors continually plugging with bits of rubber.
(proof that some cooling air is getting there if you ask me!)

once the vent channel is plugged, you are completely shutting off the cooling flow that even a stock car would have. So you create a situation potentially worse than a car without the ducts.

I never had this problem during drivers education, but in wheel to wheel it became an issue. Once in an enduro, we had 84 cars on track at the same time and rubber was flying everywhere!

brant

We ran Ferodo DS11 compound for a long time (my favorite)
then those went away (asbestos) and we tried:
Hawk
Mintex
Cool Carbon
Pagid
Performance Friction
etc.
etc.
I once tried FLAPS pads. (They didn't make it through one 20minute session.)


Hawk seems to be what we used mostly the last several years. They didn't eat rotors and they last a few events.

I'll have to look up the compounds if you need them.

Like all race pads, they are not real good cold.

Last year or so I found that Ferodo was making racing pads again (non asbestos) and we tried them. They seem to work really well for us. The front SC pads wore about 2x faster than the rears. With 2 drivers, we would go through a set of front pads in about 3 events.

Now that we switched to 930 fronts, the fronts last longer, but still wear out before the rears do.

The reason I would like to change out the rear calipers is mainly for cooling (vented rear rotors), but I believe that the smaller pistons will allow the prop valve to be open more.

I think that with the prop valve open more, the adjustments with the prop valve should be finer (1/2 turn would be less adjustment with smaller pistons than it was with the larger pistons).

I would always like to increase the rear braking with the car. That is one place where I could always pick up some time (deeper braking). The fronts will always do more work, but every bit helps.

just my $0.02

Can I Cut/Copy and Paste this EVERYWHERE?!?!? I doubt you'll get full open but it should help.

Tia... looks like you just added a 0.

The 6 rotors are slighty larger but they shouldn't be 1.6lbs. larger.

I am using the brake rotor cover, but I have a new pair of aluminum lower A arm scoops and hose that I'm not using. If someones interested in them make me an offer.

damn my previous message never made it..

Matt, can you post some pictures and details of your improved 4 lug set up?

are you still going 4 or have you converted to 5?

I just have too many wheels and tires to convert to 5 now...I gotta have the vented rotors, they are just so cool.....

I do like what I saw of your after market mods...are you going to offer them as a kit?
later, herb