Yellowzcar

iTrader: (2)

I would love some advice on a direction to go from here, as well as some feedback on my current modifications suspension wise. I am building a street legal emissions passing road race car. The car is a 1992 rs with a swapped out ls1 t56 and 4th gen 10 bolt. I would NOT like the car to be caged and it will remain a full interior car as well Fyi.

Currently the car is equipped with

Motor/Drivetrain
-99 ls1 (stock)
-True duels over the axel off of 00+ manifolds
-Rebuilt T56
-4th gen 10 bolt with 3:73's
-Alum driveshaft

----Bought but not installed is----
-Katach CNCed 806 casting heads
-Thunder racings v3 cheater cam 219/230 .602 .603 on 117lsa
-comp cams duel valve springs, retainers, pushrods, valve seals, and locks
-Ferra intake Valves
-Ls6 intake and tb
-Misc gaskets oil pump timing chain ext..

Susp/Chassis
-36/24 swaybars
-Poly bushings were appropriate
-Rod/poly founders LCA's
-S&W Poly on car adj Panhard Bar
-Sphon SFC
-Koni yellows all around
-Ebaich pro kit
-Founders solid bearing strut mounts
-Steering ball joints bearings ext are all Moog with the exception of the adjusters are UMI

Wheels tires brakes
-OE wheels repo c6 base wheels 18-9.5 (Pigs at 28lbs)
-2in alum spacers up front
-245/35/18 Pos riken raptors (horrible tires)
-Stock front brakes with drilled rotors (plans to build my own willwood kit)
-Stock 4th gen pbr rears with drilled rotors

Car weighs 3290 without me in it, 1/4 tank of gas.

Next purchase will be a set of 4 rear OEM c5 z06 wheels with 295 Nt05s all around being as i currently have pos street tires on the car. as well as gaining grip i will also be loosing 33lbs of rotational weight over my repro c6 base model wheels.

Some Pics:

http://www.facebook.com/media/set/?s...6449363&type=3

Pablo

iTrader: (1)

Not bad. I would recommend more tire and less weight, a better diff, and track time so that you can tweak the tune.
As you increase the grip you will probably find your spring rate is too low. Especially true for a heavier car.
Stock hood is heavy, true duals are heavy and unnecessary (I've run an 11.2 through a single three and you can always do single 4). Relocate the battery.
When you swap springs consider extended ball joints to raise roll center. Also consider lowering your phb. This will require sping changes.
Factory diff is weak. Tight courses will make this obvious.
Brakes are not working to their potential without an adjustable prop valve. The quicker you can slow down means the more time you can spend accelerating.
Consider a good seat and harness but without a roll bar this isn't exactly safe.

Just my 2 cents

SCCAjunkie

I'd back up Pablo's recommendations for the most part. Look into Ground Control weight jacks, as that will open up your spring choices a LOT. I think the best rear diff for what you're doing would be a T2 or T2-R. Brakes are a big deal as well, but if you're running big wheels, your options are open.

Where in PA are you?

I'm not aware of any true road racing you can do without at least a roll bar, and most require a cage. If you're just doing track days that's a different story, but generally if you go to anything timed, you'll need a bar and a harness (though there are some exceptions to that- but again that's time trials, not racing).

Here's a pic of my friend's car which is similar to what you're talking about. 600hp LSx, built T45, 10-bolt with T2 and 3.73s. Has weight jacks with 850/180 springs (I think) and 34/24 sway bar combo (Del-sphere bushings up front and on the PHB, all metal sphericals in the LCAs). We're seriously looking into the extended ball joints and PHB lowering that Pablo mentioned, as I feel we're at the limits of what we can do without them. The car is full-interior, street legal (though no emissions), and built for Track Trials and Hillclimbs. It's currently one of the fastest door-slammers at our events. I drove the car last year with the 500hp LSx motor, and properly set up, it's a very fun, and surprisingly easy (for me) car to drive fast (I was only 3 seconds off the car owner's best time on my first run ever in that car, and he almost reset the class record later in the weekend).

Let me know where you're at, and I'll be glad to help any way I can.

paul_huryk

If you have the $, go for double adjustable QA1 or equivalent struts and shocks - rear coil over if your class and budget allow.

I'm going to suggest that you start thinking about taking out dead weight as it is going to help out a lot (as Pablo mentioned) and also to go rod end or equivalent on all the appropriate bushings - poly is going to have too much "give" in your application.

Yellowzcar

iTrader: (2)

Thanks, spring wise i was looking into a GC 1000 200 setup but wasn't sure on how well that would ride on the street. I was also looking into unbalanced engineering's pan hard relocation kit, but haven't done a lot of research on them for the most part, i will definitely do some more reading. I would like to retain the true duels, but i may dump them before the axel to loose a few pounds like you said, as that makes sense as a good place to drop some lbs. The car is already equipped with seats and harnesses also that are bolted to the frame. I like ur idea of weight loss so ill be sure to start going through the weight reduction thread more carefully and pick some applicable ways to shed some lbs. I also plan on lowering my rear sway bar size from 24 to 22 to reduce hop on the street over bumps mid turn, what are your thoughts?

Also i have watched some time attack videos of your car, swell as followed your progress with it some, VERY nice, properly built car!!

IYea, the stock brakes are by far inadequate, I may go c5 route, or an aftermarket willwood kit that i would piece together, i will be doing a lot of reading on rear difs as that is something i lack knowledge about.

I am located in Zieglerville PA (about 20 mins south of boyertown on rt 73) i would love to meet up and see your car sometime too! i rarely get the chance to talk to any f body, yet 3rd gen fans in the area so it would be a pleasure.

And yes sorry for the misunderstanding, it will be track day racing.

That car sounds amazing and more or less exactly what i am striving for with this car! i would love some more information about that car.

I was actually under the impression that coil overs were a drag racing thing for our cars and was frowned upon because the reduction in wheel and tire size that you can run. But yes i plan to do some major weight reduction soon as that seems to be the most common response aswell as the logical solution for braking acceleration and handling performance.

The car is also a dd so i wanted to keep rods off anything that wouldn't hinder performance a lot, (obv not the lca's, being as you need that articulation to eliminate bind) i am in the market for some del alum bushings for the front stock boxed a arms that are on the car though as i have only heard good things. I will be upgrading to a rod rod pan hard bar eventually though

iansane

iTrader: (1)

I know they always say if you have to start a sentence with "I don't mean to offend you..." then you're obviously going to offend someone...

Well, I don't mean to offend you but...no. Just, no. QA1s are not a shock/strut meant for turning. ASTs, Koni's, Bilsteins, yes. Coil overs in the rear? Not needed. Moves the weight to an area not necessarily designed for it. Matching weight jacks with the front would be easiest to tune but even just a good standard style spring you're better off. And Poly doesn't so much have "give", as it has "bind".

Twin_Turbo

iTrader: (25)

qa1 = poser bling...there...I said it LOL

paul_huryk

Obviously you quoted my message and I am certainly not offended... While I do think that rear coil overs are not needed in 99% of the cases, I am going to put them in the upcoming CTW project car and it will be road raced - will report findings on them and any issues.

I'm going to say this, there are only a few options for the third gens, they are older now and don't earn any points from high end companies like Pfadt, moton, or penske, so we have KYB, Koni, QA1, AST, Bilstein, and a few others. And you can narrow that list down even further if you want only adjustables that aren't drag race only like Lakewoods. I personally spoke to the QA1 folks at last year's SEMA show and they told me that their double adjustables are meant for road racing and street use - they have a drag race series that would be for straight line only, but could also be street driven. I haven't tried them myself, but like what they are offering (a bit pricey though). An yone have input on this?

83RDRACR

QA1 totally re-engineered their adjustable shocks over the last few years. As Paul said they have a series for drag racers that is valved for weight transfer during straight line acceleration. These are sold under the "Stocker Star" or "R" series. The road race shocks are sold under the "Proma Star" or "Pro Coil" series. I have installed a set of the Proma Star adjustable coil overs on my custom 3 link suspension in my 83Z. The car is still under construction so no track time, but I expect good results.

iansane

iTrader: (1)

Meh. They may be amazing but spending that kind of coin I want to be getting something I KNOW is great vs getting something that COULD be great. I just don't have the extra money to be testing brand new products out. (well... within reason).

Yellowzcar

iTrader: (2)

Im not a huge coil over fan, just because of the limit on wheel and tire size you can run. I plan to stick with my konis i think. a gc setup seems to be the way to go for me after the addition of some wide sticky tires

paul_huryk

Check out CTW Motorsports wheels:

http://www.ctw-motorsports.com