High-HP FD track car question
 

Anyone here running over 400 RWHP on road courses? I'm curious as to:

* Your estimated curb weight with driver and fluids
* What brake setup you're running (calipers, pads, ducts, etc.)
* If you're happy with the braking performance and durability for sprint race distances

Thanks! I'm in the process of evaluating the RB braking system but I'd like to know what works out there for the faster FDs.

-ch

450hp here,set up for Road racing,2400 pounds(excluding driver)
brakes;Kit from N-Techengineering ,that include front/rear calipers/disc,pads,lines,ducts etc

Might want to also include tracks driven on, lap times and level of run group.

Bump! C'mon, I know there are more of you out there!

Gracer, great idea. I'd love to see some lap times at some well-know tracks.

Also, Giampiero--do you have a thread with pics/stats on your car? I'd love to see what you're doing to get 450HP and 2400lbs!

-ch

There just aren't as many people with such cars anymore and those that fit this category aren't necessarily on this forum. I've run into several people at the track that have great cars but don't participate in this forum or the "big" mailing list.

From what I've seen the best brake setup to date are the AP-front 99 Spec- rear and also the Stoptech-front and 99 spec-rear combo. I believe the degree of success with such setups is subjective. I too have been watching the "Racing Brake" thread carefully to see if the new setup is better. I have my doubts given all the issues. In any case I may not have my car much longer.

R

I did not start a tread with all the info and pictures as yet,the car is not finish yet(95%).
If you search my posts you will see some pictures of some mods.....
I will use my car for next year Caribbean Championship,races in Jamaica,Barbados,Guyana etc
The weight actually was down to 2100 ,but rules states that minimum weight has to be 2,400 for a 13B with turbo.....

Im running Ap 6 pot 330mm brakes in the front and stock in the rear. And i need more breaking power in the rear, right now it's way to much in the front compeard to the rear. So gonna go for either 99 spec, or the back break caliper system that has been posted on the forums.

JT

425rwhp
2828lbs (fueled, no driver) - oink
Front: AP Racing 5200 4-pot, 13" rotors, SS lines, Ferodo DS3000 pads
Rear: Stock, KVR Performance slotted rotors, SS lines, Ferodo DS2500 pads
Fluid: ATE Racing Super Blue
929 Master cylinder
285/30-18 Kumho V710 tires

- I run on a brake eating track. Fade and control is good. I would like to have more bias towards the rear. The RB rear kit sounds like a good complement since it can use OEM caliper sized pads (more options).

Any cooling ducts? Your car sounds very, very close to mine in terms of power/weight.

How many days/laps do you get out of a set of pads?

-ch

No ducts but was so tempted after seeing GooRoo's incredible set!

I've only done 2 track days on these pads (4 x 25 min sessions) but I think they'll last me another 2-4 sessions. This includes the 1.5 hr drive to/from venue each way through city and rural paths. Previously, I ran HPS and cooked them in 6 laps. Like pedal to the floor, cooked. Same everything else.

Friend's dad recommended the Ferodo DS3000 to me....he runs a 996TT modded to 500+ hp. I think Max Cooper runs these too.

Other item of note is that I recall the AP Racing CP5200 calipers comes with aluminum pistons. I think Gene Felber did a group buy via essexparts.com for stainless steel pistons to minimize heat soak/xfer. Essex no longer offers this... :( But GooRoo may still offer them (http://www.2dperformance.com/shims.asp).

*btw, I still have to install ur tank cover...had to run with full tanks still*

Thanks for the info, Hedge!

I'll poke GooRoo to see if he'll post some pics of his ducts on this thread...

-ch

This is a repost from Hedgehog's thread earlier in the spring, I'll update it with this year's results in another post:

Ok, to add to what everyone else has said, with a modified car and good tires those pads are not going to be sufficient. As an example, I started last year with stock brakes and about 300rwhp, and using R-comps I was cooking HT-10 front pads and front rotors every 1.5 hours of track time. Rears were lasting about 6-8 hours of track time. This is with 20-25 minute sessions, and I did have some ducting dumping air off the nose into the rotors. The fluid would be cooked after 5-6 laps in each session (depending on the track - more or less) and the pedal would be very squishy by the end of a weekend. When I wasn't attuned to it, it seemed very sudden. One corner, brakes are fine, next corner, no brakes. As I became more used to it I was able to better predict when it was going to happen, and creep up to the edge. Anyway, it was borderline no longer safe, and I'd have to slow down quite a bit to be careful.

Midway through the year I added in some titanium backing plates, and I no longer boiled the fluid anymore, but a couple additional laps and the pedal would get very hard, without slowing the car! Textbook pad fade from overheating. Definite improvement but I obviously still needed more heat capacity in the front brakes.

Fast-forward to this year and I upgraded to Damian's old 993TT calipers and custom rotors in the front. I had purchased a set of N-Tech aluminum plates, but couldn't use them because they didn't fit the rotors. If you want a set of the N-Tech plates for 13" rotors, I have that set for sale - new and unused. Here's the link: https://www.rx7club.com/showthread.php?t=634299

It took alot of work, and more $$$ and time than I wanted, but I'm very happy with the result of the project: (as always, click pics for the full size images)

Here's where the air enters the ducting, just below the oil coolers. This is a 7x3" duct that I got from RacerPartsWholesale with #6 stainless mesh over the top to prevent stuff from getting in. It's bolted to the nose and held tight to the oil lines with zip ties.

http://www.dekoning.net/images/rx7/B...Duct-small.jpg

Here's the routing of the brake duct hose. This is the same 3" silicone hose that Crispy uses I think, again from RacerPartsWholesale. You have to be circuitious here to avoid hitting it when you turn the wheels full lock. I was able to smash the hose into an oval and keep it tight to the wall with zip ties. Also the top part is tied to the a-arm with ties as well. It is fastened on each end with a 3" Breeze stainless constant torque hose clamp.

http://www.dekoning.net/images/rx7/B...ting-small.jpg

Here's the backside where the hose is clamped to the duct. I did roll a bead on the piping so it won't disconnect itself. You can also see that the edge of the duct actually goes inside the lip of the rotor, in this case about 3-4mm. It is flush with the position of the original stock plate so there is a 10mm lip around the edge of the main plate to make this happen.

http://www.dekoning.net/images/rx7/B...side-small.jpg

Here's the duct opening. I'm really proud of this part, it took a while to make and is practically art. :D about 75-80% of the hose area is able to get inside of the 12.67" (322mm) rotors I'm using. You can also see there's a bolt missing here that would normally hold the stock plate on. I modified the spindle and cut the part that normally holds the threads for that bolt to get more room for my opening. This is the main way I was able to make the hose input area so big. I did this because Damian did the same thing for his ducts. :D

http://www.dekoning.net/images/rx7/B...ning-small.jpg

Here's the plates from the back, you can see how closely they fit inside the rotors, I would say not more than 1mm gap at any point around the rotor. You could ask how I was that precise, and I'd have to say that I spent alot of time fitting, sanding, and refitting in the end I let the rotor itself do the final 'clearancing' hahaha. The entire brake duct is sealed except for that small gap, so ALL air is coming from the nose of the car.

http://www.dekoning.net/images/rx7/B...Size-small.jpg

Sorry about the quality on this one, but here's one last pic so you can see the welding work to seal the inside of the duct and the overall shape. The material is 6061-T6 Aluminum in 1/8" thickness. Thickness was chosen because of the removal of the one bolt. With the lip around the edge and the welding this thing is SOLID, and I would say it weighs something like 1-1.5 lbs. Sure would have been nice to go carbon fiber, but cost was prohibitive.

http://www.dekoning.net/images/rx7/B...view-small.jpg

So, results? This setup now with Hawk Blue pads all the way around is capable of braking for 20-30 minute sessions even though I upped the power 10-15% with the pads getting better and better as they warm up. Not once have I had any sort of fade even over 4 days on the track. I also have used less than 1/2 one set of pads. Depending on the outside temp I actually tape off part of the ducts to get the rotors/pads up to operating temp! I'm going to switch pads simply because I don't like the corrosive dust, but that's more of a cosmetic deal.

To answer your original question, I think the thread you are talking about was the one I started last year...

https://www.rx7club.com/group-buy-center-69/titanium-backing-plates-stock-fd-calipers-564700/

However I think you should get proper ducting from the front of the car IN ADDITION to better race pads and titanium shims and you will be good to go. I spent probably twice as much last year on pads and rotors last year because I didn't get the proper setup in the first place, and the brakes were always questionable.

So kind of measurement did you take to come to the conclusion that you require bigger rear brakes as opposed to more rear bias?

Hyperion,

I think you saw my street/track car setup at Laguna seca a couple weeks ago:

https://www.rx7club.com/3rd-generation-specific-1993-2002-16/pictures-my-custom-brake-duct-inlets-397125/

Wilwood SL-6 calipers with 13" rotors in front and '99 spec in back. N-tech brake ducts. Making about 350 RWHP (dynodynamics). Car weighs about 2750lbs without driver and can withstand continuous hard use at laguna seca for a whole weekend on one set of pads (something the stock brakes couldn't come close to doing)

I've been running pads by Raybestos which will last a LOT longer than the Porterfield R4 pads I used to use. Sometimes I can get several weekends out of a set - depending on the track.

On my other FD - a dedicated race car - I have AP racing front calipers and the 99spec rear. Front brakes are ducted. About 400rwhp and 2400lbs without driver. No fade issues at all - but I have not had this car at Laguna Seca which is certainly the hardest on brakes for a high HP car in California.

Hey, John! Thanks for the post. I'm going to be at Laguna on the 4th with SpeedVentures and the 6th with TrackMasters. I had a decent test at Infineon with the Hawk pads so I'm going for broke (literally) at Laguna to see what they can do.

This time around I've got temperature strips for the calipers and heat-sensitive paint for the rotors. I should be able to determine whether or not I'm working in the optimum range for brakes.

I may do ducts anyway just to be able to tune the temps, but I'd really like to get this to work sans ducts if possible...

-ch

Good luck with your testing! I really liked your car - it is much better sorted out than most conversion cars and very clean.

I'd love to hit Laguna Seca again this year but I don't think I can make it happen. San Diego is kind of far.

- John

that brake cooling duct is awesome. does anybody make that for an FC?

Mazda Motorsports and AWR both sell brake ducts

track brakes for a high hp FD.... are we there yet?

no.

the stock FD system is 68/32.

the RB system adds a huge uptick in rotor mass but is 70/30. the controlling issue being the need for an E brake therefore the required retention of the stock rear caliper.

the RB larger rear rotor helped by moving longitudinal balance from 71/29 to 70/30

i am overall delighted w the setup for the majority of FD owners. when combined w the ABS and, perhaps different pads front and rear you have a really nice setup.

a year ago when i first spoke w RB i was just looking for more rear brakes. i am still looking for more rear brakes.

going really fast on a road course requires alot of rear brakes, more rear weight, more rear rubber, and finally, the ability to adjust brake bias from the cockpit on the track. brakes can win poles and races.

i know. i have won 27 National SCCA Races in GT3, the June Sprints twice and have a 2nd at the Runoffs at Road Atlanta as well as 2 3rds and a 4th. i have held the lap record at Blackhawk Farms, Road America, Mid Ohio, Indianapolis Raceway Park, Brainerd and Road Atlanta.

there is a feel to maximum braking. the car hunkers down over the rear tires. it doesn't trip over it's nose.

you will never get there w a non-adjustable system. depending on the track during the race you may find yourself adjusting while racing.

back to the FD.

the bottom line is the car needs more rear piston area. a 4 piston rear caliper.... a caliper w 1 inch pistons would balance at 68/32. that's back to OEM but we need more. a 1.125 piston would be 63/37 w the RB rear rotor.

once we have too much rear it is simple to add a cockpit adjustable brake proportioning valve and de-emphasize until max braking is achieved.

i would like to run a RB caliper w smaller pistons if available. if not Wilwood makes a 1.125 4 piston that Max Cooper runs. i will adapt it to the RB rear rotor.

i plan to fixture an E brake and have some ideas that i will share as i get into the project.

the snow is about ready to fly in wisconsin and i will be addressing the brake issue this december.

howard coleman

Can't wait to see what you come up with. . .

:-) neil

Chris,
I've treaded lightly in the RB brake thread, but my impression is that this doesn't need to be so difficult. I'm braking down from 155+ at VIR, 155 at WGI, and 150 at Summit with no significant issues.

That's a StopTech front, OE MC & rears, Ti backing plates, dedicated front ducting, AP 600 fluid, and PFC 01/97's. All in all a fairly pedestrian setup. I might upgrade the rear or the MC at some point, but it isn't urgent. Car is 2750 lbs, 345 whp, 285 hoosiers, running 2:12 at VIR, 2:13 at WGI.

Fritz has probably run every setup out there, and seemed to like either Porsches or Brembos, with whatever rears without too much problem, and he was coming down from 165 and running 2:08's in Brad's old car. That had Porsches & 99/willwood rears with a custom MC.

Howard,

any progress on getting more rear brake bias now that you have a RB setup upfront ?

:-) neil

Im planning on getting on the the track this summer. Im looking at a Project Mu brake setup. This thread is helpfull, thanks.

FWIW, I haven't had any actual braking problems using the stock FC brakes (same calipers as the FD but a smaller rotor). I just cracked a brake rotor but I'm pretty sure it's due to a defective rotor rather than anything else.

Car is 2450lbs wet (no driver), 530rwhp, 30-35 minute sessions.

I have the brakes well ducted very similarly to GooRoo's setup but using the AWR backing plates for the FC. I'm also going to be using some 3" NASCAR-type fans in the 3" hose to help.

Howard,

any update ?

:-) neil