Tripster

At what RPM should a 3.3 reach full Boost? I have had some tell me that they are at full boost @ 3000 RPM. So the question is at what RPM should the average 3.3 / K27 reach the .7 Bar / 10 psi? Mine seems to be very lazy reaching 10 psi.

ProtoCab

Depends on what type of K27, aftermarket header system and post-turbo exhaust you are using. Too many variables with the limited info presented.

PorschePhD

Most will hit full boost with bolts ons and some type of K27 at or around 3K.

Tripster

I have something going on thats just came into play I think. This weekend I took a trip to the Dragon, car ran great there and back, I got 21.8 mpg on the road there. But while playing with a few of the car clubs that was there also, I found my car not hitting full boost ( 10psi ) until 4000 rpm.

38D

I think it is less what RPM, and more how long. My 964T takes around 500rpms to build full boost. So if I stomp on it at 3000, I get a full 0.7 bar by ~3500. It will build faster if I am going up a hill.

I you are stomping on it at 2500 and not getting full boost until 4000, you have a problem. Could just be the o-ring on the intercooler.

pete77930

I'm at full boost by 2700 rpm's 2nd-4th gear...1st gear blows by too quick to matter. but im running a custom ceramic bb turbo out of the old caddilac lemans car. the down side is that my motor redlines at 6700 and the turbo is designed to hold boost all the way to 8k. I'll fix all the imperfections when I decide to stop racing motorcycles.

pete77930

be sure to check the oring on the throttle body side of the intercooler...if its not seated perfect, it'll blow out every time.

Tom F

Repeating a post I had on Pelican. This is about my 3.0 Turbo (no intercooler).

I have SC cams, a Euro exhaust and a K27-7200. Also, a pesky and hard to pin down vacuum leak. So, I would guess that I am not going to see the boost come on as quickly as it would if everything were correct. However, I would like to get an idea of what to expect, as I go about trouble shooting the vacuum leak. Currently, I see peak boost (0.8 bar) at 3600 to 4000 rpm. I get, at best, 0.5 bar at 3000 rpm. No boost to speak of below 2400, maybe 2200. What are owners of similar cars seeing? Thank you in advance. Tom

DonE

Depends - what gear? On the road, in first, mine hits 1 bar about 4000. In second, its about 3800, in third, about 3700 and fourth about 3600.

On a Dynojet dyno, in third, 1 bar is around 4000. On a DTS engine dyno (loading the engine), it was around 3500.