kind of stupid turbo question...

[Vendor Defendor]

This is kind of a stupid question about turbo’s, I’m still learning about all this stuff, after all I’m used to working on stuff like 350’s, which is what I got my edjamacataion on. Heh, but what’s the point of running anything bigger than stock on the street if you can’t run more than 17-18lbs? I know you can if you run higher octane gas or alcohol you can run more boost, but if you don’t have this, like me, and you can only really turn up the boost at the track, and even then only up to like 22psi which from what I understand the stock turbo is good for… it kind of seems pointless… unless I am missing something big here (which I probably am…). Is there some sort of advantage? Do they spool up faster? I would think 20psi of boost is 20psi of boost. If some one could straiten that out for me, I would appreciate it.

Neil

 

[turbosam6]

Psi is not cfm. For example, a stock turbo at 20 psi moves a lot less air than a TE 45A at 20 psi. Does that make sense?

 

[UNGN]

The stock turbo can put out 22 psi, but it is very restrictive on the exhaust side when it does it. A larger turbo like a TE44 or TA49 makes the same 22 psi with a lot less pumping loss in the engine so it will make more HP at the same boost.

Your assumption is right however. If the longblock is still stock and boost is kept to pump gas levels, larger turbos offer few advantages over the stock turbo. They may make more top end HP due to the reduced exhaust backpressure, but may also give up a ton of torque down low if they do not spool at a low engine RPM.

If you have a 100% stock car, bolt a TE63 on in place of the stock turbo and run pump gas, it WILL be slower than a stock car.

Run Race gas and 27 psi of boost, it WILL be faster than the stock car (and then blow up shortly afterward).

There will be some crossover boost level where the area under the TE63's HP curve becomes greater than that of the stock turbo and the larger turbo is quicker. It won't happen in pump gas territory, however (unless a loose converter, alchy injection, ported heads or other things like this are involved)

 

[Quickturbosix]

Originally posted by UNGN
If you have a 100% stock car, bolt a TE63 on in place of the stock turbo and run pump gas, it WILL be slower than a stock car.

Run Race gas and 27 psi of boost, it WILL be faster than the stock car (and then blow up shortly afterward).

I like the "then blow up" part.

Listen to the man he knows what hes talking about.