I'll see if I can find it.
Here's what a guy wrote on MatrixOwners, we were talking about the same topic. Only difference there is, there's only like 4 or 5 people that actually have or have had a turbo car. Not a whole lot of knowledge on FI but makes for "interesting" reading.
Quote from LHO-RTS:
OK here is the deal with this:
Boost is boost, no matter how big the turbo is. If you have a big turbo making 4 psi, it will make the same power as a small turbo making 4 psi. The size of turbo does not effect power if the boost is exactly the same.
I have proven this with my 94 cavy turbo. I had a smaller t3 KKK K26 turbo that made my car run a 14.85 1/4 mile when it was setup at 4psi boost. I ran the exact same time, 14.85 1/4 mile with the current turbo i'm running which is a HUGE-a** GM5 turbo from a 6.5L diesel, and i was running, you guessed it, only 4 psi boost.
Boost is boost, you will get the same amount of power from the same level of boost no matter what size the turbo is.
The main diff from large to small turbos is where the power comes in and where it falls off.
Case closed!
So I wrote back:
Case re-opened, this is SO NOT TRUE! Please dont post info thats so friggin false its not even funny.
A. Now that you have a Mack truck turbo it takes longer to spool it up, thus making slower launches with better top end. Kinda equals itself out.
Let's not compare drag times as power examples, thats just shooting in the dark. If you have a dyno comparison then show it.
If a T3 makes 300cfm at 4psi and a T25 only makes 200cfm at 4psi, you're trying to tell me that will be the same power? I think not mang. Thats why people buy big a$s turbos, higher HP
LHO writes:
^^ No man, I took fluid dynamics in school.
You must understand, 4 psi is 4 psi going into the engine. It doesn't matter what is putting it in there. 4psi from a larger turbo just means there is more volume and less velocity.
And don't rag on a car you've never seen. My cavy actually has no lag that way it setup. I have the vids to prove it!! I got the turbo for free and decided to throw it on for run. The reason it only make 4psi is that it is too inefficient for the engine. Its on an engine with less than have the displacement of the engine the turbo came off of. The V6 simply doen't have the exhaust pressure to spool it fast enough to make more than 4-5psi.
When you read a boost gauge it's taking the reading from the intake manifold pressure, correct? So if the pressure in the manifold is the same, the engines power will be the same.
I finished the debate with:
An engine is a air/fuel pump, the more air/fuel you get in there the more power you make.
If you have 200cfm of air and the correct amount of fuel, you'll make 200whp(VERY GENERAL ASSUMPTIONS HERE)
If you have 300cfm of air and the correct amount of fuel, you'll make 250+whp.
The more air/fuel you cram in there and correctly ignite, the MORE POWER IS MADE. SO, the size of the turbo directly effects the power output.
