Turbos

[Williamc]

Any one out there that can help me figure out what size turbo should I use. I'm building a stroker motor and need help trying to find a good turbo kit.my bottom end is already stud and top end is done also. Before I made my changes my car ran 10.40 at 128 mph not bad for a first run but need more power my compression is 11.8.1 is that to much for turbo. Hope to hear from anyone soon...

[camcojb]

Originally Posted by Williamc

Any one out there that can help me figure out what size turbo should I use. I'm building a stroker motor and need help trying to find a good turbo kit.my bottom end is already stud and top end is done also. Before I made my changes my car ran 10.40 at 128 mph not bad for a first run but need more power my compression is 11.8.1 is that to much for turbo. Hope to hear from anyone soon...

yes, compression is all wrong for a turbo. If you're building the motor, can't you lower the compression?

[chevguy]

Compression way too high and to run those figures your cam will be wrong for turbo as well.

[RoadHammer]

Unless you want to run methanol and have a range of 12 miles, drop the compression ratio to about 9:1 for gasoline

[DBL NKL]

Blower and Turbo motors need lower static compression. Somewhere in the 8.0 to 9:1 depending on how much boost you're going to run. As the boost increases, your cylinder will gain pressure and your final compression should be under 12.5 at maximum rpm to be safe on pump gas. Also, if running high boost you'll want to O-ring the block and the heads. You need to plan your build ahead of adding boost because the builds are a lot different than traditional aspirated motors, and more expensive too.

A good rule of thumb on a boosted motor is a good block with billet or splayed mains, a premium crank, billet rods, a good set of blower pistons and tool steel pins. You'll also need a cam grind that suits the application as both supercharged and turbo grinds are much different than traditional cams.

[Swiftshifter68]

Originally Posted by Williamc

Any one out there that can help me figure out what size turbo should I use. I'm building a stroker motor and need help trying to find a good turbo kit.my bottom end is already stud and top end is done also. Before I made my changes my car ran 10.40 at 128 mph not bad for a first run but need more power my compression is 11.8.1 is that to much for turbo. Hope to hear from anyone soon...

Waaaay more info' necessary before anyone can help you out. You almost certainly won't find a "turbo kit" that will fill the bill, and don't say "Ebay" or you're fired. Give a solid description of the parts you'll be using in the motor build, what you WANT from the combo' as far as E.T. or HP or mannerisms, etc. Be honest, don't daydream yourself into a $2400 turbo if you don't need it.

What:

Engine/CID/topend, etc. be specific

Car/chassis, including race weight, Single-purpose Drag, Street/Strip, or ??

Transmission and/or stall, use a good turbo-friendly converter company, PTC, JW and Ultimate are a few notables

Fuel system, you'll need volume, Magnafuel, Aeromotive, Weldon, Prod. Eng., expect to spend over $1K on just the fuel system from tank to engine

Power range desired, including max RPM

Horsepower desired, dont' say "alot" and expect good advice

Rear axle setup and gearing, depending on race weight, maybe <3.55:1

Performance desired, E.T. at the strip, MPH in the 1/4 or ??


Lots to think about when it comes to turbo selection, and be careful not to get swayed by any local yocals that might be naysayers to all things boost. Some guys know Roots setups and claim to have a handle on boost of all kinds, they would be wrong.

I'm almost ready to start on my Chevelle after all these years of gathering parts and financially treading water, I am anxious to dive in, fists flyin'!


---==Temio Williams
Yuba City, CA