I'm going to be building an enginge based on the Chevy LSX small block. The block will be stroked to ~ 500 cubes. We will be using the ZO6 heads and strengening the internals to handle lots of power. I originally wanted to put the new 5.0L Whipple supercharger on top. After taking some measurements, there's no way that will fit under the hood of an Escalade without SERIOUS cutting.

Here's where I am undecided. Do I use the 3.3L Whipple supercharger or do a twin turbo setup. I would be looking for somewhere between 800 - 1000 HP to the wheels with either application. The 500 cubic inch small block should have enough torque off the line until the turbos kick in. Then again, I really love supercharger whine!

Which way should I go?

 

You don't need 500 inch to make 1000 to the wheels with twins,that's alot of stroke.You will have a hard time keeping the heads from lifting as it is.Have you looked at some of the aftermarket blocks and heads(5 bolts per hole),that would help with keeping the heads down.This sounds like a cool project.

 

I haven't, but I hope my engine builder has. I should be getting together with him soon to get into the details more. I'm still trying to figure out if I should go with the supercharger or the twins.

 

Dart makes a block that you should look into.I did a project for GM in 2000 for trucks with a wipple for the current LSX motors, and the project was scraped because the truck made to much to power and could not meet gas mileage.

 

Have you checked with these guys?

http://www.nelsonracingengines.com/engines-home.html

 

Yes. I sent the link to my engine builder about 3 weeks ago and he got all insulted!

 

you could easily twin turbo it and have the same output..

 

Forget the 500 inches, way to much stroke and a crappy rod ratio. And it is not needed.

 

What is a better "Rod Ratio"? What do you mean by this?

 

The rod ratio is the ratio of the center to center length of the rod to the stroke of the crank. ie, if you run a 4" stroke and a 6" rod the ratio would be 1.50-1 of course the length of the rod is limted by the deck height of your block and how little compression distance you are willing to try on your pistons. In my 540 inch big blocks we would run a 4.250 stroke and a 6.7"rod giving a nice ratio of 1.58, this also gave a nice ring package as well as good deck thickness for strength.
I like to see a minimum compression distance of 1.25 inch in anything that is expected to have any service life at all. I would not use a rod ratio of less than 1.5 IMHO and I would like to see 1.7 or better if possible. Of course the ratio also depends on your port cross section and your air flow numbers as well as cam timing.

 

I'm guessing that having a rod ratio that is too low creates an excess of lateral forces on the area where the rod connects to the piston? A larger ratio is more verticle pressure and therefore able to rev higher and/or last longer?

"I like to see a minimum compression distance of 1.25 inch..." What does this mean?

Thanks!

 

Maybe you should have Derboost build your engine. If your engine-builder hasn't talked to you about rod ratio, can he build a 1000hp turbo motor to move a 6000lb truck with a fair amount of reliability?

Sorry if this comes off as rude.

 

[QUOTE=Alex]Maybe you should have Derboost build your engine. QUOTE]

LOL sorry, I did that for 25 years and i've had enough.. (well except for my own projects )

 

distance from pin centerline to top of piston deck.

 

You might be onto something here! DerBoostMaster seems to be a deep well of knowledge.