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Spring rates and a front lip?

Old 09-04-02, 03:04 PM
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Question Spring rates and a front lip?

I've recently put a chevy 350 in an 87 GXL and im wondering about what a good setup would be as far as spring rates and coilover suspension, also who makes a decent front lip for racing puposes? thanks
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Old 09-04-02, 03:41 PM
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Depends on the type of racing.. But with the heavier front end (let's skip the arguments on how much, suffice it to say it's 100-200lbs heavier), I'd probably start with 500/300 front to rear spring rates, coil overs of your choice. I like the Mazda Comp setup with konis, but there's plenty of other options.

Front lip, depends on what kind of racing again, but either the Demon Speed or MikeL front splitter looks good, not sure they're really necessary though.

PaulC
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Old 09-04-02, 04:59 PM
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It would mostly be club road racing. I would like to upgrade the brakes, does any one make a good big brake kit for it or would you suggest just upgrading the stock brakes?
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Old 09-04-02, 05:46 PM
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I performed an engine conversion like yourself and have probably similar weight up front. (iron block/heads V6 with 30lb turbo and 15-20lb intercooler/piping.

Are you running aluminum heads and intake manifold?

Is it only have an alternator or other accessories?

Do you have an aluminum hood and what rims are you running?

I bought K2RD.com coilovers with 400lb springs up front and 250lb springs out back and KYB AGX adjustable shocks. This is a 90% street car and 10% track. These rates IMO are right on are totally streetable and really improved the handling of the car. I can really push it in the corners now with confidence. Unless you go with an exotic shock (meaning big $$$'s) you are limited to about 400lbs on the front. K2RD.com didn't recommend any stiffer out back as they said it was hard to tune with anything stiffer.

I assume you have 5 lug brakes and vented rotors from the GXL/T2 style? I would just put on race pads and see how they work.

If you want to drop major coin then check out the upgraded AP Racing available from Corksport. Realize that larger brakes will typically require larger rims. Braking is a function of tire width and traction/brake pad surface area/...... and the larger brake rotors just help to dissipate heat before brake fade comes into play. 13-14" brakes should withstand 99% of the braking torture you can throw at them.... but they also cost mucho bank.
Upgrade is $2500-4K :o!!!

Here is the address for Corksport:
http://www.corksport.com/rx7/2rxsus2.html

I'd try the stock 5 lug vented brakes with upgraded pads. Pads make a huge difference.

GNX7
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Old 09-04-02, 11:20 PM
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For the spring rates, figure at least 500# up front, maybe more. Most NA FCs in the Southeast running in SCCA ITS class are running between 400-500 up front. Don't be surprised if you need up to 600# in front, given your added nose weight. Paul's suggestion of 300# rears is right on, or at least very close.

For brakes, if you have the 4P brakes from the TII/GXL, then save your money for now and just run the Hawk HT-10 or Blue MT4 compound. Don't let someone talk you into the Blue 9012s just because they have been running them for years without any trouble. You will need the extra braking power. In addition, make certain that you have plenty of air flow to the center of the rotors via ducts in the front air dam. Mazda Comp makes a great duct that bolts to the spindle to attach the hose to.

As for a lip, they do work. Mounted properly, they will increase front down force, aid cooling, and they look good. Don't bother calling Demonwhatshisname, he likely doesn't have any, and I'll sell you the same unit for a lot less.
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Old 09-04-02, 11:22 PM
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Heck, I'll even pay for the phone call! 800-882-7231

Chris Wire
Racecar Engineering
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Old 09-05-02, 12:58 PM
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Im running with the stock hood with a hole cut out for the air cleaner an aftermarket aluminum intake but stock heads and only the alternator, and most of the car is stipped but we will be putting a cage in. Thanks for all of the info
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