I've seen many turbo manufacturers list the rating of their turbos as max rated HP. My question is, does it matter the size of the engine and does the max HP rating of a turbo changes if it's fitted on a different size engine.

I have a friend who built a 427 LS1 engine, using 6.0L iron block, in a sand drag buggy and he wants to turbocharge it for 1000HP target. I am guessing he will need PT76 or maybe PT88 turbo if going single. Going twin turbo, he may need two TE34.

Any suggestions. What cam would be good for a TT or ST setup.

 

Maximum HP from a turbocharger remains -about- the same as long is it's reasonably matched to the displacement of the engine.

Smaller displacement engines will generally be able to make more horsepower with a given turbo vs a larger displacement engine because it will be operating at a higher pressure ratio, which is running most turbos in their sweet spot.

(A turbo is more efficient at moving 60lbs/min @ 35lbs of boost than moving 60bls/min at 15lbs of boost)

As far as your friends 427ci LS1, I would recommend two to4 based GT61's, or a single To6 flanged 88. (Both would have great response and capable of 1200+hp). A single 76 is capable of his goal, but backpressure will be out of hand with that much displacement through a single T04 based turbo.

I would also recommend just running an iron 6.0 block with better rods and pistons, as a 427 really isn't necessary when combined with turbocharging.

 

so if i had the choice of a forged 350, 355, 383, and 396 crankshaft with forced induction pistons, would i be best off with a 350?
thanks

 

I guess it depends on your goals and preference.

I prefer 350-ish ci, because it has enough low end power to be fun on the street, and you can make as much power with it as necessary.

In my case, more displacement/torque would just make it harder to drive.

 

Just ease out the clutch.