good start for a twin turbo set up?

[absintheisfun]

I know very little about turbos, but the more I read, the more interested I become. I'm pondering the possibility of using a twin setup on my build, and want to ask the experts out there if this is a good starting point for a block: (Its a GM Crate 290horse/350.


Horsepower:290 @ 5100 RPMTorque:326 @ 3750 RPMCompression Ratio:8.5:1Block:Cast Iron 4-Bolt MainCrankshaft:Nodular IronHeads, Chamber Size:Cast Iron, 76ccValves (I/E):1.94"/1.50"Camshaft, Lift (I/E):.450"/.460"Camshaft Duration @ 0.050" I/E:222°/222°Intake Manifold:Not Included

[shmoov69]

Fine for "normal" and not insane power levels.
Book: Turbochargers by Hugh Mccines (SP?)
Forum: www.theturboforums.com
Lotsa' reading!

[RSX302]

I know very little about turbos, but the more I read, the more interested I become. I'm pondering the possibility of using a twin setup on my build, and want to ask the experts out there if this is a good starting point for a block: (Its a GM Crate 290horse/350.


Horsepower:290 @ 5100 RPMTorque:326 @ 3750 RPMCompression Ratio:8.5:1Block:Cast Iron 4-Bolt MainCrankshaft:Nodular IronHeads, Chamber Size:Cast Iron, 76ccValves (I/E):1.94"/1.50"Camshaft, Lift (I/E):.450"/.460"Camshaft Duration @ 0.050" I/E:222°/222°Intake Manifold:Not Included

I'm far from an expert, but I have run a couple of boosted engines. With the heads on that motor, I think this will be your limiting horsepower factor. With either superchargers or Turbos, tuning is critical...read...read...ask...read...ask. Meltdown is quick if not done correctly. I think if you keep it under 8 psi, you should be good. I have found that with factory timing on a 9:1, cast iron heads, it will ping at peak torque around 6 psi with 91 oct. So anything under 8 psi on a 8.5:1 cast iron head motor should be fine. I would start at 5 psi and work from there. Intercooling will allow you to increase roughly 2 degrees timing or 2psi boost with the same oct.
There are ignition boxes you can buy that will retard timing under boost to help aid with detonation.

With this, I would think you should get about 100hp. Don't know what the GM create engine is rated for, but I don't think I would go much more.

[Texas Hotrod]

The sizing for the turbos on a twin system will have to be exact to get good results on a small engine. Twins look better but a single will probably give better results (having less lag and less expense).
You can easily double the power of a naturally asp'd engine by adding a turbo system, but it has to be built to handle the boost. Head gaskets will be the main concern. Felpro makes a layered metal gasket that seems to presently be the hot ticket. Everything needs to be studded and forged pistons are a must (unless you run low boost).
CSU builds carbs that are good right out of the box.
MSD has BTM boxes to handle the ignition retard and Snow Performance has a nice adjustable water/methanol injection kit that works as good/better than an IC.
Do your research and plan a budget (a big budget). There's many people here that can help point you in the right direction.

pics of a twin turbo system I built for an SB 406:
http://rides.webshots.com/album/560430391GBdRww

begenning stages of my twin turbo BB Chevy 460 engine:
http://rides.webshots.com/album/561744085yGuGhB