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88 days until my next event...

Old 07-26-07, 11:38 PM
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88 days until my next event...

As the title says, I have 88 days until my next track event and need to do address the following:

1. Overheating. It sucks that after 15 minutes of driving hard in the afternoon, that I have to take every other lap to cool the car, i.e. short shift and give point-by's to the Vettes and Porsches I was passing in the morning sessions. I have the CWR race radiator and have done some minor duct work to direct more of the air into the radiator. I've tried Water Wetter, Purple Ice, and running all water - nothing really helped. I'm considering the Greddy WP and alternator pulley kit to raise the point at which the water cavitates however I am concerned with belt contact at higher RPM's. Does anyone have experience with these pulleys on the track?


2. Rear gets loose under heavy braking. I'm running .1" of toe in and if the car has less than half a tank of gas, the rear end wants to see what the front of the car is doing. Not being able to brake later is costing me at least 2-4 seconds per lap. I replaced the pillowballs about a year ago and upgraded to the Rotary Extreme trailing and toe links at the same time. Do I need more toe? I have the Zeals coilovers and normally run a 3/4 or 4/5 (F/R) dampening - maybe I need to run 4/4? I tried searching but didn't find anything helpful. Is there something I'm missing?


Daniel
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Old 07-27-07, 12:07 AM
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Dunno if it's apples and oranges but the waterpump underdrive helped my FC quite a bit.

I also had an issue with the car getting loose under the brakes, turned out that one of the rear calipers was bad and I wasn't getting even braking force. Might want to inspect your calipers.
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Old 07-27-07, 12:37 AM
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I've been trying to solve the overheating issue by starting simple. Tried $6 worth of Distilled Water, then a $8 dollar bottle of Water Wetter/Purpl Ice. I went "nuts" last time by purchasing tin snips and $15 of sheet metal to make ducting. Next up in price is the pulleys

I haven't inspected my rear calipers though - I'll look in my FSM to see what I need to inspect. I manually track my brake rotor and pad wear but based upon your experience, will put it into Excel to see if there is an uneven pattern - Thanks!
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Old 07-27-07, 04:55 PM
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Have you looked into a proportioning valve in line with the rear brakes? Have you tried running less grippy rear brake pads? Just some thoughts, too much rear bias will make the back end squirm under hard braking.

Can't help too much with the cooling issue, turbo cooling is far beyond my ken.

PaulC
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Old 07-28-07, 02:43 PM
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Originally Posted by Silkworm View Post
Have you looked into a proportioning valve in line with the rear brakes? Have you tried running less grippy rear brake pads? Just some thoughts, too much rear bias will make the back end squirm under hard braking.

Can't help too much with the cooling issue, turbo cooling is far beyond my ken.

PaulC
I've always noticed my the rear of the car getting squirrely under heavy braking but now that I recently started using race pads on both front and rear calipers, it has excabertated the problem. I'd like to think that there is something inherently out of wack with the car and the track is bringing the problem to light.

Time to do a search on the proportioning valve. Thanks.
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Old 07-29-07, 07:07 AM
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Are you running any toe in/out in the rear alignment?

If anything you want to run a lighter duty pad in back. You're loading up the fronts so much under hard braking that the back gets really light. Have you had any problems with the rears locking up?

In any case, the proportioning valve is the "proper" fix for this. Going through the rear suspension is also a good idea.

Good luck,

-bill
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Old 07-30-07, 05:14 PM
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Originally Posted by wrankin View Post
Are you running any toe in/out in the rear alignment?

If anything you want to run a lighter duty pad in back. You're loading up the fronts so much under hard braking that the back gets really light. Have you had any problems with the rears locking up?

In any case, the proportioning valve is the "proper" fix for this. Going through the rear suspension is also a good idea.

Good luck,

-bill

As far as I can tell, the rears aren't locking up. I'm assuming the fronts are what's triggering the ABS when I get on the brakes really hard in a straight. I'm also running .1" toe in. I'm going to try bumping it up to .125 and then order the proportioning valve.

Just ordered the Greddy Pulley set to address the cooling issue. Also put a deposit on the Shineauto GTC front end
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Old 07-30-07, 06:51 PM
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Do a tight duct to the radiator. Route fresh, cold air as directly as you can. We just did an FD which was overheating badly from "spirited" driving. We built a complete aluminum tunnel from the air dam opening, under the front mount intercooler and fixed it to the radiator, sealing it off with silicon hose. The front opening was 2 1/2" x 24" only and all the air was rammed through the radiator. The temps stayed low the entire race weekend.
Here's a pic:

http://edmontonrace.com/publicdocs/2...sc00943_19.jpg

The underdrive pulley is a good idea, as the water pumps tend to cavitate at high rpm.

I'd also try to rishen the fuel up a bit, this helps keep the temps down as well.

On the braking front, silkworm is probably right. Run less aggressive pads out back. You are transferring a lot of weight forward, the rear is getting light and the rear suspension does a bit of hopping.

-Trent
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Old 10-26-07, 01:21 AM
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Well, just wanted to give an update:

Over the summer, I installed the Greddy water pump pulley and since the GB for the Feed hood was going on, couldn't resist...

I'm only running the Greddy water pump pulley and found out you can still run with the air pump with the stock belt. Once I get my smog cert, I may install the rest of the pulleys.

My track event was on Monday and with air temperatures around 80F (not sure what the track temp was), the car's temps were rock solid and never went above 220. I think the last time I was out there, I was seeing temps starting to go up 15 minutes into the session where I would have to run a cool down lap once temps hit 230F. I was running a 50/50 mix so think with a 30/70 mix, the car could run cooler.

As for the rear brake bias issue, I changed back to a less sticky rear pad (Porterfield R4S, I was using the R4) and found that the stability had improved, but the car still wanted to dance under heavy braking with anything less than a half a tank of fuel. Previously with the R4 in the back, the rear of the car really wanted to swap ends but now, it's a bit more manageble. The car has about .1" of rear toe in but I may start looking into a proportioning valve.
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Old 10-28-07, 12:24 AM
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What kind of Spring rate on the back ? Most of Japanese coil over have very hight spring rate... special on the Race on. Is not suprise to see you have 800 0r 900LB spring rate at back... This set up Work Well with very big Wing at back.. this could be your problem...
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Old 10-31-07, 05:32 PM
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Originally Posted by diyman25 View Post
What kind of Spring rate on the back ? Most of Japanese coil over have very hight spring rate... special on the Race on. Is not suprise to see you have 800 0r 900LB spring rate at back... This set up Work Well with very big Wing at back.. this could be your problem...
Spring rates for my coilovers are 9kg/mm|8kg/mm F|R...or in English:

502lb/in|446lb/in F|R
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Old 11-01-07, 02:15 PM
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I think a proportioning valve is your best bet. I use a balance bar + in-car adjuster, and certainly as the fuel load gets lighter I begin to experience more of what you are describing. I don't believe that decreasing your braking potential (by running a less 'grippy' pad) is the right way to solve the problem.

It's nice to have the adjustment in-car so you can adjust accordingly as conditions change.
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