Originally posted by fst4dr:
I got about 8 with the supplied pulley. After installing the 3.12" pulley I get 9-10. It seems to vary.

I start building boost at about 2500.

3000 = .5
3500 = 1
4000 = 2
4500 = 2.5
5000 = 3.5
5500 = 4.5
6000 = 6
6500 = 7.5
7000 = 8.5
7500 = 9-10

Those are aproximations, and with the smaller pulley. With the stock pulley I didn't start making boost until about 3-3.5K rpms. The boost only really starts to climb qhickly after about 4500 rpms. Hope that helps.



Simon

In comparison to your data, basically what I am seeing is 5psi by 5000rpm, 8psi around 6500rpm and then 9.5 to 10 when the rev limiter kicks (7500rpm or so)

It looks like the numbers are close. If possible, I'm going to measure the pulley diameter because, I had planned to purchase the 3.12" pulley. It doesn't appear that I have to do it.

Another observation, temperature related, is the fact that I am seeing an 80 degree temperature rise, between the inlet of the MAF to the upper intake manifold temperature. I used a laser temperature detector to check. I was always told that boosted motors are fine without an intercooler, 80 degree rise being the max. Well, seeing how soft the engine gets once it is 150 degrees at the manifold, I think an intercooler will be next on my list of mods.

Christopher A. Wong chris@ctamotorsports.com CTA Motorsports