can anyone else hit 10+ psi before 3000rpm? i never noticed it until today and i didn't know if that has anything to do with the water injection kit i installed, or if it was normal to have that much boost at that engine speed.

 

Can't say as I've ever really paid attention to an exact number at an exact speed, but I'm pretty sure I've seen 10 at 3000rpm or even lower. I don't think that's anything strange. Remember it's an SC, not a turbo... no spoolage necessary.

 

yeah, i just wasn't sure what rpm it had to be at to put out that much boost. it still has to be turning a certain rpm to put out a specified amount of boost....


anyone know the rpm/boost ratios for the pullese blowers and factoryys?

 

Some info here... http://www.automotive.eaton.com/prod...argers/M62.asp

You can't just equate boost to speed like that, though. You can relate airflow to turbine speed, but how much boost that translates into depends on the engine parameters, physically and operating. It's all a big inter-related package. For this car, though, observing 10psi @ 3000rpm isn't abnormal.

 

as you start to drive more, or your engine is starting to get more broken in, you will find that it will be a tiny bit easier to boost, in turboes and in sc.

and at 3700-4000 rpms in 3rd gear will get you alittle under 12 psi of boost i hear but not positive.

 

a positive displacement sc does not need max rpm to produce peak boost. a centrufugal sc does. the twin screw design on the css is not totally independant of rpm but its as close as you can get with forced induction. thats why they call it a positive displacement supercharger, make the engine feel bigger. it helps to think of the lsj as a 3.2 liter, the toque curves resemble a much larger engine. look at the dynos of a lsj and then look at an vw r32. (it helps to note that the css actually crank output in near 250 hp)