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Finally found a donor car......


rzaron53

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Well I bought a 91 LB9 Z28. Its a real piece of junk. Its a non G92 car so it has the drum rear brakes and the 3.08 rear end. What is the easiest way to convert to disks? Swap rear ends? If so is there a web site someone can point me too? I'm pretty sure I can perform the swap, its just the detail things like getting the e-brake to work that I'm worried about. Also, what should I be paying for the set-up? couple hundred bucks?

 

Are the 3.08 gears suitable for the track or are the 3.42s better? I would guess the higher the number the better.

 

Also, what do you guys think about the Spohn and Baer 1LE front kits? I think I read that the Baers are floaters. This seems like the way to go.

 

Thanks....[/b]

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I'm pretty sure I remember glossing over some 3rd gen disk swap threads here, try searching for that. Also, this years rules allow you to use a 4th gen rear, which you can find with a Torsen diff and 3.42s and disks for cheap. The only catch is you'll probably end up running 4th gen wheels to get the right track...but those are cheap too. You'll want to have 3.42s or 3.73s for gears.

 

On our cars, all legal brake setups have floating calipers, as opposed to more modern floating rotors or even opposed pistons.

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Well, Al, I've always favored opposed rotors, floating pistons and slotted calipers from the 2LE package...it's good for an extra 20 feet in braking...as to the rears...you can pick up a good 98 up rear complete ready to bolt in with disc brakes, 3.42 and a torsen or auburn (depends on the year) for around $350 from the salvage yards...or try eBay where they sometimes go as cheap as $150 (but shipping can be expensive if they're far away)...congrats on getting a starter car and have fun with this giant size Revell kit car...Richard "boy does that glue smell funny" Pryor

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oh, and invest in a factory workshop manual...the 1990-92 are all the same so any of the three years will work for you...again, they're on eBay (one set right now) for around $30 or less. and you can get 2000-02 16x8 rims for around $50 each for the rear..this will give you the correct offset for the rear in a 3rd gen with a 4th gen rear...rp

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So I just bought the american sedan legal 12" Baer kit for the fronts. They had a kit for the back but it was ~1000 bucks. I think I will go with the rear end swap. So any 98+ rear end is the hot set-up? Are they all 3.42s or do I need to look for some identifing marking? Is the torsen or auburn set up better? Any tips or advice would be appreciated. As soon as I get the rear end swapped I'm dropping it off at rp's place. It handles like crap. It actually has yaw at freeway speeds....scary.

 

 

Thanks,

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The stock 98 up are as good as the Baers plus you get the whole rear end....pop the case cover and check to see if it has the auburn cone setup (terrible) or the torsen gears (far superior)...find the rear ration by dividing the number of teeth on the ring gear by thenumber on the pinion gear....you can buy take off torsens from www.slpeng.com for around $100...if you have to replace the gears I'd go with the 3.73 for the norcal tracks..rp

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I dont think all 4th gen rears are created equal. Not all of them had the Torsen, not all had 3.42s, and not all have the same brakes though they're all disks.

 

The 93-97 rear disks are smaller than the 98+ cars. Either will be just fine. I run the earlier ones and they've proven to be consistent through the entire run.

 

I think only the v8 stick shift cars came with 3.42s. I'm not sure which years or motor combos came with the Torsen, but like Richard said, you can get a take off Torsen for around $100. The only way to tell is to take off the cover and take a look.

 

Since you probably will have a hard time counting the teeth on the pinion, you can always turn the pinion one full turn and count revolutions on the axle flanges to figure out the ratio. (both axle flanges need to be off the ground)

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According to my notes all 98's came with a Torsen as well as a few early 99's and all the rest 99-2002 had auburns...buy a cheap rear and put in new ring and pinion 3.73 and torsen...cost you around 250 total plus rear but it'll be new...and check the axles...spend $225 for a new stronger set and peace of mind.

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How about the 90-92 F-body disk brake rear end? Is it just a matter of availability? THe reason I'm asking is because I saw one on e-bay for ~400 including shipping. It has the 3.23 gear since it came off an auto. The sticks had 3.43s I believe.

 

Thanks

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I was digging around the thirdgen.org website looking for rear end swap how-to's and found a thirdgen drum to LS1 disk conversion:

 

http://www.thirdgen.org/newdesign/tech/ls1reardisc.shtml

 

What do you guys think about this? I think I might try it with mine and then buy 3.73 gears for my G80 posi rear. Any obvious drawbacks? I get to keep the stock offset this way right?

 

????

 

-Thanks

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I think you have it backwards

'93-'98 had the Auburns.

'99+ had the Zexel-Torsen rear ends.

You don't want the clutch type Auburns, they wear out..... quick.

'94+ MN6 6spd cars had the 3.42.

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Well I just ordered a 91 3.42 G92 rear end with new proportioning valve and e-brake cables for $500 bucks. NOt a bad deal I think.

 

Whats the word on rebuilding the heads? Any reputable people in the 650/510 area?

 

Any recommendations for a good mid level (in cost) cat back exhaust?

 

Thanks,

-Ron

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CAT-back?? Why would you run cats on a race car? Most non-chain owned exhaust shops will fab up a straight pipe from the y collector to just in front of the rear axle cheaper than any pre-fab system made to go up and over the axle. Some guys run little race mufflers (single chamber flowmaster for example) to try to boost torque...I say run it wide open.

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Well, I'm going to keep my CMC car cali legal. I live in an apt. and don't have a truck and trailor. I still want to race though. I figure I can get up to the 230hp limit and stay street legal athough I may have less area under the curve.

 

I have a vin F LB9 but I got stuck with a single cat somehow. Anybody have any ideas what my street legal options are?

 

Thanks,

-Ron

 

BTW, I just finished gutting the car and tearing out the a/c. It should be illeagal to have this much fun....

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Great, this will be fun, a CMC car that is street legal and driven home after the races...good luck!

 

Wasn't this the formula for CMC when it first got started? I saw pics of Todd's car, still with the top on, racing, and he drove it home.

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My first car, a very fast '84 Camaro, was a smog legal track car. I'll never forget driving it to Thunderhill for a late season HPDE and practically freezing before I got to the hotel (no heater)! I wanted to put on my helmet to keep warmer, thought that was a little too wierd for the street though!

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If anyone is looking for a 3rd gen car for a CMC buildup, the local autoshopper has a 1990 IROC and a 1991 Z28 listed for $1200 each...831-622-9024

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