junito1

I went to an event earlier this month.
The track is all second gear except for the last straight throught the finish.

After the second run I got the burnt clutch smell. But It ended up being the brakes. It had me worried because I wasnt going 100% on breaking.
I did not feel any brake fade.. BUt that smell is killer. heh

I have new OE rotors and rebuilt calipers(by me). With metal master pads----my buddy had these same pads at the event and he wasnt having any probs.I ALso removed abs. It seems front right brake smelled more than the front left. Rear were fine with no smell. BUt the car doesnt pull to one side under braking...



What would you track gurus suggest is going on?
The only diff between me and my buddy is that he has slotted rotors. IM rocking OE blanks.

Black91n/a

You're overheating the pads, that's why they're smelling. You need to get some proper track pads if you want to do track driving at anything but a beginner level really.

junito1

Gay. My buddy with his 240sx recommende them.(w/ Q45 brake upgrade) HE had the same pads at the event. HE had no issues with overheating them. Maybe he is not as hard on the brakes as me?

DO you think because he has slotted rotors-- is the reason why he isnt over heating them?
HE even had better bigger tires than me on the front.

Oh well. I guess ill have to get some noisy track pads.

Stevobob

iTrader: (1)

There may be less load on his, maybe his car weighs less, there are too many factors. Or maybe you drive harder than him :P

junito1

I pretty sure i wight less. As im fully gutted.
THings i still have:

TurboII NO ABS=D
still have passenger seat
Powesteering
I also still have to remove the floorboard tar.
Stock dash modified it weights a lot less. ( i cut 90% of the metal out. Only 3 small peices used for mounting out of the stock mounts.) weights a lot less.

U can see the firewall clearly through the center radio section. which kinda sucks. Im looking to fab a switch/guage panel where the radio goes.

LargeOrangeFont

iTrader: (7)

You may not be hard on the brakes, you are just on them to little for too long. This builds up much more heat thank getting on the brakes hard for a brief period.

Most beginners do this. Be aware of that and try a different braking method next time.

Also, Metal Master pads are not really "agressive" brake pads. They are going to smell when they get warm.

arghx

iTrader: (3)

I absolutely annihilated those autozone brand brake pads and "OE replacement" rotors from a couple runs at Tail of the Dragon.

rx7racerca

iTrader: (1)

I never had any problem with even the OEM pads (still have 'em in a box somewhere, actually) in hard lapping at lapping days - this at a track that has a very long front straight - close to a mile. So hard on the brakes going into turn 1-2-3, bringing the speed down from ~200kph to around 60 in turn 3. Of course, the long straight means a long stretch of on-the-gas acceleration to cool on each lap, too.

Your driving style, and level of aggression may affect your brake heating issue - since your friend is a different driver in a different car, even though both are similar performance and weight stock, there's not much comparison to be drawn there. You have a fair bit more engine, which means higher speeds on straights, even if carries more in the corners - and there's no particular reason he should. Plus, he's done a major brake upgrade, which mean's unlike stock, where a 4 -piston RX-7 should have better braking performance than a 240, he's got more brakes (larger mass to act as a heat sink, more swept area) than you now. Are you left-foot braking, by chance? Because if you are, you may be riding the brake more than you realize. Have you checked that your calipers/pistons are allowing the pads to retract slightly? Ie., the front wheels should spin fairly freely when jacked up, not stop immediately due to drag. Are your brake ducts still in place? They factory ones on TurboIIs and GXLs aren't fantastic, but they do get cool air in the vicinity of the brakes.

Try some more aggressive pads - Hawk HPS or HP+, assuming you want something that can do double duty, street and track (maybe you aren't driving the car on the street if the interior's gutted?). HP+ are more aggressive and heat resistant, but also dust a fair amount and are fairly hard on rotors, so not as good if street duty - FYI. Porterfield R4-S for a more street-friendly solution or R4 or R4-E for more track oriented are another choice - no experience myself, but other people find them VG for track and street use.

Slotted rotors should not affect heating - they may cause more heat, in fact, since the slots act to shave the pads slightly, preventing glaze buildup, which in turn lowers the friction coefficient of the pads.

Gene

iTrader: (1)

Brake ducts were the best thing I ever did for my braking longevity at track events. Also I suggest immediately switching to Motul 600 fluid and making sure to bleed it before each event, and fully flush the system at least once a season.

What track are you driving at?

Also the expand on what LargeOrangeFont said: It's counter intuitive but it's true. If you're slowing say from 100 to 50, you're going to put the same amount of heat into the pads whether you brake at 100% effort for a short period or 50% for twice as long. So, if you brake at max effort for the shorter period, it means you're spending more time off of the brakes, which gives them more time to cool.

junito1

I am a more agressive driver than he is. I basiclly lock the tires on every entrance.
I dont think i saw him lock the brakes once. But he does have better rubber and bigger size tire .than me

I do NOT ride the brakes.

MY car does have an issues to where it doesnt roll on slight slopes. Thats why i rebuilt the calipers. But it stil has the issues a little.

MY original brake ducts are still in.

LargeOrangeFont

iTrader: (7)

Fix whatever issue your car has with the brakes.

The brakes are going to smell at the track.

Gene

iTrader: (1)

The original brake ducts don't really do anything.

turboeric

There's your problem. Your brakes are dragging slightly, which heats up the pads even when you're not using the brakes. So the pads start out hot and don't get much opportunity to cool down. Are you using the retractor springs on the pads?

junito1

yes i made sure i had all the srings on the pads to keep them seperated.

Photonic

Locking your tires is never a good thing.

Locking your tires = Grip you are not using to slow down faster. Are you Rev Matching?

slpin

iTrader: (9)

it depends *which* tire is locking up

Photonic

ANY tire locking up is not a good thing. That's still a tire that is beyond its limit and is therefore upsetting your line and increasing your braking distance.

junito1

I dont like locking my tires up, i was pointing out how hard i brake.

But i think my problem is what Turboeric pointed out. Because it was the only passenger front brakes that smelled.

What i dont understand is why the would be dragging?
Any knowledge on why brakes drag would nice. I do have all my retractor springs ont he pads/caliper.
Chris

Photonic

Sticky piston?

Gene

iTrader: (1)

What track? Counter clockwise or clockwise? You can put more load on the outside brake if you're trail braking a lot.

junito1

Stock pistons? on the rebuilt calipers? yes

The track was clock wise.

Elite_Deforce

I have slotted on mine, they kick ***. I would think the OE brakes would suck ***, esp if they are old...

junito1

Im trying to double check if i did my ABS elimination correctly.

I tried using the FSM of rx7city.com but it doesnt specify how the lines run on the non ABS models and the pictures were not clear enough.

Does anyone have a link to a brake line diagram. ?the MAster --> Proportioning valve-> calipers.

junito1

I have read like 5 diff ABS removal threads.
I have some f- ing questions because i got confused while reading.
DO ABS models have different proportioning valves?
DO ABS models have more than one brake line that run the rear of the car?
ONe or 2 short lines that go from proportioning valve to master.

I did my abs removal by using a donor car.
I used :
1 left, 1 right front brake lines
1 non-abs master
1 non abs front proportioning valve.
The line that goes to the rear and everything else in the rear was left as is.

SYmptoms.

Pedal feels funny. A bit mooshy. But the car still can lock the tires up.
Brake balance feels a bit off too. KInda goes with the pedal feel.
Passenger front brake seems to be dragging --

Gene

iTrader: (1)

You probably didn't get all the air out of the system.

The ABS master cyl is also larger, which means a stiffer pedal feel since it displaces more fluid with less travel.

On ABS only two lines exit the master cyl, one for the front and one for the rear. They pass through the prop valve and go to the abs box. Two front lines and one rear line exit the ABS box, the rear line splits back by the rear wheels.