Dumb question maybe.. How do I know when the turbo is out of its efficiency range?
07-02-2015, 10:43 PM
#17
Rennlist Member
If your running 16 psi your exhaust should see 16 psi back-pressure. If it read 17 on the intake and 20 on the exhaust then you have meat the limit of boost at 16 for that turbo If your exhaust has more pressure difference then the intake you run to "reversion". That's where the hot exhaust gasses are trying to go back into the cylinder because the intake pressure is not overcoming the exhaust. Then you get a "popped head gasket" or "rod out the side of your block". I talked to Mike Lindsey about this for some time. So I bought a back pressure kit, I know not to over boost my engine.
It's not often you're going to get equal boost to back pressure, and it doesn't mean you're going to have significant reversion or power dropping off right away, just because back pressure is a bit higher.
Not to mention: at part throttle (even with some boost) the back pressure will always be significantly higher than the absolute intake manifold pressure, which would be the mode you are running in 90% of the time (especially on the street).
