I know plenty of people have made good power with a 90mm but at what hp level is it not optimum?
Have you tried a 105mm or larger to see if it gained anything?We make 2500 hp with our combination and a 90mm TB.
We haven't Mike, at least not yet. I'm not sure it's going to make any difference. The intercooler tubing on our car going to the TB is 4-inch OD, which is the OD of the 90mm TB. The OD of the 105mm TB is 4 5/8-inch, so we would have to use a 4 1/2-inch to 4-inch reducer to hook it all up. Not a big deal I guess but we just haven't done it yet (although we do manufacture this transisitional tubing). Throttle body size is much more critical when it comes to naturally aspirated or nitrous engines than with forced induction engines. On the other hand, if you have a "draw through" supercharger system, like the Ford GT or the '03-'04 Cobra style, in which the supercharger draws air through the TB instead of blowing through it, the size is very critical and "bigger is always better" is the word.Have you tried a 105mm or larger to see if it gained anything?
I had a pump gas engine that was 445ci with a YSi trim and it made 1030 or so with a 90mm throttle body. We were going to test a larger one to see if would pick up anything, but ran out of time and then never did it. The engine is gone, unfortunately.
I make 900hp+ at the motor with a 75mm TB and 2 1/2" cold piping at 16 psi. My friend with the same setup 75TB and 2 1/2 cold side made over 1000HP. I think he was around 1100hp and that was because the turbo was maxed out.Well then my 105mm is way over kill. LOL! I'm just looking for 1000hp at the motor, I guess if I ever start looking for more power than that I won't need to upgrade the TB.
I agree but I would go further back than the pipe to the turbo outlet size.I think on a boosted car it depends entirely on what is before the T/B if you have a 80 mm pipe feeding a 90 mm throttle body you probably would not see any improvement with a 105mm , conversely if you had a 110 mm pipe feeding the 90mm throttle body you would probably see an increase by changing to a 105.