beechx1

The KW supercharger kit uses a separate oil cooler for the supercharger. It is the aluminum colored one on the passenger side of the car in the first picture of the original post.

The Mocal oil cooler does nothing to the supercharger. Making more power by boosting the car produces more heat. There are many discussions concerning hot oil (especially with boosted cars) in the competition section. Spinning a bearing seems to be the most common engine failure mode for track run cars. Losing lubrication due to overheating the oil can be a cause for spinning a bearing. Since I run the car on the track, I wanted to keep the oil temperature down as much as possible to keep my car reliable.

Nik2k

excellent bro! thanks a lot for your answer !! i dont track my supercharged kraftwerks ap2 ! so dont ned this

manolo1492

What was the main reason in choosing the 91 vs 81 blower? I'm trying to decide on this and cant make up my mind for the life of me I know more boost is better in most cases, but in a track car build which blower is best suited overall?

beechx1

The -91 will make more boost across the rpm range than the -81. I can limit the boost at higher rpm to keep the heat down by using a restrictor plate or a waste gate without affecting lower rpm boost. Thus, I have a fatter torque curve without too much boost at high rpm.

Also, for only $300 difference, it seemed like there was little reason not to get the -91.

Habitforming

If I could do it over again, I'd get the -91

Revin9K

Did you go with the standard pulley?

Habitforming

Not sure if that was directed at me or beech. Yes I have the standard ap2 pulley. Peak boost I've seen in my logs is 17, on a very cool evening. In this hot weather it's more like 15.

beechx1

I also have the standard AP2 pulley. As my initial post says, I only made about 12 PSI of boost. The 3" coupler to the intake manifold was leaking particularly badly. In fact, this coupler blew off while my wife was driving the car. I replaced this clamp with a T-clamp and found it leaked worst than the worm drive clamp (the coupler bulged between the T's). I went back with the worm drive clamp. I also replaced the 3" coupler that attaches to the intake manifold with a 3" to 2.75" reducer.

My wife and I just finished fixing all the boost leaks. The only leak now is a small one through the KW re-circulation valve. The worm drive clamps that KW supplies can be tightened much more than I am used to being able to tighten worm drive hose clamps without stripping them.

Revin9K

i dont understand why the kit has these issues out of the box (boost leak, bolts snapping off, etc)? it seems that the SOS kit is much more reliable and worry-free. There is a $1500 difference between the two kits however.

s.hasan546

more than that. I just ordered the kw c3-91. I believe it comes out to almost a $2000+ price difference. The bolts snapping has been a common issue that they are trying to fix. This is the first i heard about boost leak tho