JETSWU87

Details...

PTE Miata
2400ish lbs
205 R6
1.6 brakes Hawk DTC 60's all 4 corners (points system have to stay 1.6) and have cooling.

I bought the flying miata kit a couple months ago but never installed, the car brakes great...infact better then near everything in my class however I wonder if i can get even more out of it. Also to get a little heat away from the front to survive the 45min races.

My question is for the guys who've played with adjusting this thing a lot, I though i read someone who said even with the valve at full rear...it isn't enough to lock up the rear brakes, granted pad, tire compound etc all play a role..but anyone else share there experiences?

TIA!

99Racer

Read thread...
https://www.miataturbo.net/showthrea...893#post933893

My own experience is 1999 with stock brakes PF97 pads front
& rear. Stock Front / Rear bias is ok on shorter / flat tracks. However, one track has a 110 mph off camber down hill corner. Trail braking into this one is scary without reducing rear brake bias. Otherwise, changing front/rear bias was not needed in my view. rear pads last 2x front... Wilwood prop valve mounted inside car on tunnel beside shifter, similar to FM targa car.

JETSWU87

Actually already read that thread and feel a few steps ahead.

I've run dtc 60's in the front for about 2 years now but just changed to 60's in the rear this past season and it made a pretty big difference. I don't have a huge issue with locking up fronts anymore because I've adjusted my driving style. From what I've read the 1.6 stock valve is the least amount of rear biased out of any miata so im debating on changing it...or just leaving it be and not having another failure/leak point.

I hear you on the trail braking fast forward to 1:40 in this video, there are times im fighting a lot more then this to keep the car straight on hard braking.


I'm running a fun day in November where im planning on taking brake temps etc, but it would be a good time to try out the valve. Just weighing my options and wanted some opinions from guys on track with R compounds.

99Racer

I noticed you still have a full interior... the 99 racer is a gutted out, caged race only car. So no issue with normal day to day driving (brake squeal, dust, etc.) So, no brake backing plates front or rear, no front fender liners (to increase air).

Fast track (with the fast off camber corner) 90 mph average speed, ~ 120 mph peak (near stock NB1 engine). 2.5 mile, 10 corners, 1 hard braking point per lap, 2-3 much lighter braking points. Ran successfully but front wheel bearings (grease) was showing some heat stress.

Slower track 3 miles, 20 corners, Multiple braking points, 75 mph average, ~110 mph peak. Front brakes glow red a couple of times / lap. Front wheel bearings definitely getting hot...

Added 2 1/2 brake ducts (fog light holes) on front to reduce heat on short track... Good on hot days (and heavy braking track), too cool on colder days (and less demanding track). Front now has too much cooling. Had to adjust (reduce) rear bias as front brakes never got really hot... (or red). Taped over 1/3 of brake duct inlet to adjust for cool days.

All races 1 hr to 3 hr long. Brakes are good all day long... No fade even when red hot.

p.s. change your brake fluid at least 1 time / year to reduce water content and chance of fade.

JETSWU87

Car's been a dedicated track car for years...and is caged now. I've had some issues with too much cooling in the past on cold days, did the same thing you did. I bleed the system every event...cheap insurance.

Thanks for the info.

Leafy

iTrader: (1)

On my car, I've only ever tested the brakes hard up till 80. BUT on street tires I'll still lock the fronts first, but just barely, with the bias valve all the way rear. With 275 hoosiers I've only locked up an inside front, mainly because the tires werent mine and I didnt want to really push the braking and risk flat spotting them. This is 1.8 brakes with parts store front pads and pre-warmed (drag the e-brake) ebc reds in the back. I eventually want to get the car setup so that in the dry on hoosiers I can run the same pads front to back and not have the bias valve all the way rear, then be able to move the bias rearward in the rain.

JETSWU87

Thanks for the info leafy, did it make a noticeable difference in performance?

Leafy

iTrader: (1)

Holy **** yes. You know how the car normally has that ho hum I kind of stop ok feel? with the prop valve its more like, thank jesus for inertial reel seat belts or I would have just eaten the steering wheel.

JETSWU87

haha well no i don't, or I'm just use to it. I think Im going to swap it in and play..i have a traqmate so the data wont lie.

hustler

iTrader: (6)

I have the prop valve dialed in exactly where I want it after about two sessions. It works and it doesn't matter which brake locks first, it matters how the car turns on the pedal.

hustler

iTrader: (6)

I bleed my brakes like once or twice per year, lol. Huge brakes = awesome

JETSWU87

I'm looking forward to trying it, bleeding mine every event is overkill as the fluid usually comes out clear...but between that and the clutch it's just good practice and takes less then 10minutes if you have someone on the pedal.

hustler

iTrader: (6)

I can drink a beer in about 10 minutes whilst talking **** at the track to my friends.

JETSWU87

who works on their car at the track?

cucamelsmd15

Im in the same boat. I have DTC-30s in the front, and leftover HT-10s in the rear. Ive been thinking about putting the DTC-60s in the rear (as well as the front, for that matter).

Maybe its time to pony up for the prop valve. I cant get the car to trail brake worth a damn.

hustler

iTrader: (6)

Shocks, blance, alignment, and comfort help as much as pads. It takes a lot more effort to go fast in some of the other cars I drove recently at Hallett, mine and Crusher required no thought...get in and go.

Kinavo

iTrader: (1)

Changing your alignment will definitely help you get some trail braking action.

I have been toying with the idea of a prop valve too. I have a 97 miata. If I upgrade my front brakes to the larger MSM calipers and rotors, would I need a proportioning valve or can I just put a more aggressive pad in the rear? Or ditch the whole MSM front brakes idea? The car will be turbo as of next season.

Leafy

iTrader: (1)

Stock brakes in the front and sport brakes in the rear would be the better upgrade if you had to do just one and weren't already killing the front brakes when you run your chosen motorsport activity. Upgrading the front on these cars without upgrading the rear is just silly. If completely removing any bias valve still doesnt result in enough rear braking force on the stock brake setup, you dont stand a chance with bigger fronts.

hustler

iTrader: (6)

Can we please not do this **** on our forum again? Really, please, stop it.

Anyone here who's going fast in a Miata runs a Wilwood prop valve and but they biggest brakes we can fit all the way around.

Leafy

iTrader: (1)

Only if its needed. It doesnt sound like kinavo needs it. And IMO, running just upgraded fronts will make normal stopping distances longer since you'll be locking the fronts at less pedal pressure and not letting the rears contribute enough grip. Once you get to the point that stockers are heat soaked and beyond their operating range, the bigger fronts would stop better.