Question about supercharged engines

[Glucas21]

I know supercharged engines don't require any method of cooling the air intake, but since it doesn't heat up the air as much as a turbo how much does it really help to do so? And between an intercooler, aftercooler or water/alcohol injection, what is the best for a supercharged engine?

I have also heard that a blow off valve is not really nessecary with a supercharger, until you get above 10 psi of boost, is this true?

[bigmansm]

Cooler are i more dense And the more dense the air is the better the a/f can be. Cooling the air before it is compressed will reduce the horsepower loss from heat soak.

[Glucas21]

I know why it works, thats not my question. I was asking for specific information about using them on the E36 engines.

Originally Posted by Glucas21

I know supercharged engines don't require any method of cooling the air intake, but since it doesn't heat up the air as much as a turbo how much does it really help to do so? And between an intercooler, aftercooler or water/alcohol injection, what is the best for a supercharged engine?

I have also heard that a blow off valve is not really nessecary with a supercharger, until you get above 10 psi of boost, is this true?

All supercharger kits I have seen come with a BPV(bypass valve). You cannot run a blowoff valve because you do not want to lose metered air.. BPV's are necesary to bleed off boost at low RPM.

As far as charge cooling, a blower gets hot compressing air. Anything over 7-8 lb boost to me, would benefit from charge cooling.Or any lower boost setup that runs for longer periods of time.(which could easily heatsoak)
An intercooler requires far too much plumbing and boost loss for a centri blower in my opinion.
An RMS aftercooler(water to air) suffers NO to very little boost loss and takes about 60-65 degree of ambient temp out of the IAT's.
Ex. on an 80 degree day, IATS with 10 lb boost are about 180 with an aftercooler, the temps drop to about 115, all the time, no matter how much you drive it.
Spray WI after the cooler, triggered at 5 lb boost, those IAT's drop to a peak temp of 93 degrees. An aftercooler and WI , together, work BEST to me on a centri blower.

WI alone, is a part time solution that works, but ONLY when it is triggered. Part throttle and before trigger point, offer NO benefits. Also a clogged jet, lack of fluid spraying, pump failure, hobbs switch failure, wiring failure, all lead to it NOT WORKING at all. Too much to rely on as a SOLO safeguard.
Although WI alone is proven to dramatically lower IAT's, it simply does not do it as well, as uniformly and as easily as an aftercooler.

Together though, the aftercooler and WI combined is the BEST WAY to do it. I have installed and tested many.


I have tested and documented these results, on BF's.
A centri's IAT's are ambient plus 100 degrees. You reduce the IAT's 65 degrees with the aftercooler and an additional 22 degrees with the WI.and those are peak numbers , in alot of cases the temp numbers are lower than I have stated.

[GOTUBCH]

Just spray some Nitrous in it. That will cool it off too

Yeah, until the bottle is empty!!.