When I rebuild, I plan on throwing down some real cash for a blower setup 355 or 383. I'd like to keep at least 10:1 compression ratio, and i want to be able to run 12 psi d1sc twin high flow intercooled daily driven and 15 psi at the track (up to 18 if i can handle it). I'm talking about a STOUT bottom end. Racemaster crank, all forged internals, splayed 4 bolt mains, etc. Is this feasible or am i dreaming?

 

Sorry, forgot to say, it's an LT1 block on a 97 Z28.

 

If you are going Forced induct why would you want 10:1 in the first place? With that much boost, no more than 9:1

 

Once you realize how eazy it isn't to change pulleys on your supercharger, i doubt you will want to swap em everytime you go to the track. Youd also want to reprogram your computer for more boost when you swap. Just build it 8.5-9:1 and you should be fine with that high boost on pump gas. The 10:1 won't give you that much power, or much more off boost driveability than 9:1.

 

What he said!

Also, be ready to spend a lot of money for the things you may not have even considered. Here's a few.

Fuel delivery is critical for a high boost SC setup. Most people end up spending $1.5-2K or more depending what they end up with. I currently have in the range of $2K in my fuel system and am upgrading it again this year.

Drivetrain upgrades will depend upon how you are going to use the car. If you plan to go to the track and use sticky tires, you will need a new rear end, also ~$2K. You will also need a heavy duty driveshaft. If you have an M6, the stock T-56 will be fine if you use only street tires. But you will need a McCleod Street Twin clutch for ~$1K. The T-56 will stand up to pretty heavy track use as well, once you exceed it's capacity, you are into real serious territory. I'm less familiar with the stock automatic for hi-po use with street tires. But I do know you can foget it at the track - it will need to be upgraded or replaced with a stouter transmission.

Pistons are critical. They are the weak link. Strongly consider having the crowns ceramic coated, use an excellent brand ( I have had good luck with JE).

A careful tune, with an AF ratio of not less than 12.5:1 is also crucial.


Good luck.

Rich Krause

 

Hey guys, I appreciate all the help. How much power would i lose if i dropped the cr to 9:1 compared to 10:1. Also, how much extra boost does that kind of drop allow you to run?
Sorry i didn't give a better breakdown of the car. I've already got a moser 12 bolt with 33 spline axles, T56 with Mcleod clutch (not street twin), but I have a dual kevlar disc built by a reputable shop down here as i wore down the organic one very quickly, and a pro 5.0 shifter. I plan on running an LS1 aluminum if that will hold. If not, I guess I will fork over the dollars for a carbon fiber, but I thought those weren't legal in some competitions. So with that setup, I do plan on using slicks or et streets.
As for bottom end, I'm not sure what kind of pistons i'll be running. Are JEs lightweight? I am trying to go weight consious as possible with a rotating assembly that will hold 700 or more at the engine. Is forged aluminum as strong as forged steel? I would imagine not with the extra heat i will be running. What is the biggest injector size I can run on the LT1 computer? I'm leaning towards 72# or so. I've heard something about it not working with low impedence injectors.
Already have spark taken care of with holley annihilator ignition and coil, and Accel extreme 9000 wires and accel plugs. Fuel will probably be Granatelli 255 in tank with an A1000 in line and aeromotive adjustable fpr (already have). I know it's gonna cost some money, but the way i set the car up, I am way ahead of schedule for alot of the side stuff.

 

There's no way I'd run a 10:1 compression w/ large boost. Just won't work w/o a lot of work.

I would strongly advise against the carbon fiber driveshaft. C/F is strong, but it doesn't take vibration well(like the vibration you'll see on the street). I remember someone on here posting about broomsticking a c/f shaft after about 15-20 miles.
Didn't know c/f driveshafts weren't allowed in some competitions? I can't think of any drag racing classes that outlaw them.

I'd go w/ a good set of JE slugs for the motor. Something in the -31cc dish should work good. Some good Lunati rods and a Callies crank should hold what you want.

The LTx computer is not compatible w/ low impedance injectors. I think the largest high impedance injector you can run is a 55#. Your only alternative there is to either buy a FAST system or buy Jeff Stevens' impedance converter box. If you're wanting 700 @ the motor(which comes to a little over 600 rear wheels), you might be able to make due w/ the 55s.

http://www.fuelairspark.com
http://www.acceleronics.com

There's plenty of ways to do the fuel system. The GMS/Aeromotive setup you specified should be plenty for your car.

 

You could run 50# or so injectors and run a higher fuel pressure, which will make them flow more. LS1's use 24# injectors, but run 4bar fuel pressure, so they're rated at 28#.

I'd go with a chromemoly ds or one of denny's driveshafts. If you can break it, he'll replace it!

 

Cool. I found an injector calculator, and it said 700 HP can work on low 50# injectors. If I do decide to go low imp, what do you think about the impedence converter? Is it a good unit? I'd like to keep the stock computer... highly tuned of course.
I figured the carbon fiber was more of a racing unit, but i'm glad you stopped me from putting it on a street car. Do you have a website where i can see one of these chromemoly or Denny's driveshafts. We have a good custom driveshaft maker down here, so I might give him a call too.
I guess my main question is still how streetable would this car be? I still have 2 and a half years left to pay on it, so i won't be buying anything else for quite a while. Could i pull it off being driven daily, or should i invest in a 1000 dollar junker to drive while my baby sits? I would rather drive it everyday. Thanks for all the help guys.

 

Personally, I wouldn't drive it everyday. I'm shooting for a similar number and there's no way I'd want to drive it everyday. I would buy a beater to drive around in. I got a 4-cyl. truck I drive to work and fetch parts with. Since gas prices look like they're gonna skyrocket this year, it's nice to drive something that'll go a week or two on a tank of gas.

You can find info on Denny's here. I ran a Spohn HD unit in my car for two years and really liked it. Steve's great to deal with too.

I really like the impedence converter. The instructions are straight forward and the box is well made. Considering it's about the size of a deck fo cards, it's easy to mount too. Plus, Jeff's a pretty nice guy(met him in Memphis last year).

Don't forget about tuning. It's pretty critical w/ a blower car.