Jake, if they are not that efficient, why do you run a 911 fan & shroud on your Type 1 motor in the plague?

3 reasons.

I had the shroud left over from another job the shop....

My engine makes peak HP at 8,500 RPM, I shift at 8K. The 911 fan is much better for taking revs compred to the TI fan, I will agree with that.

the 3rd reason is the fact that the stock TI system is more complicated at the track. with the sharpbuilt system I remove 4 bolts and 3 wires and the entire shroud is removed in 3 minutes, making the engine capable of being removed in 10 minutes when I grenade something, which does/has happened.

I cut 3 large holes on the back side of my shroud, to let air pass through with less restriction.

The biggest reason is that I could not find a TI DTM,, and Joe would not make one for me because they were too much work.

with 12:1 I have no overcooling issues, and with 220BHP you don't drive it on a cold or wet road unless you want to end up in the ditch.

just to jump in on this one :)

Jake, did you find cutting the extra holes in the shroud made much of a differenceon your type1 motor?

I never did any back to back test on it. When you rev the engine and there is enough back pressure to almost blow the shroud off the engine, you can pretty much tell something is wrong.

I know that Joe Lociero tried to work out a "ratio" thing for the stock shrouded T4´s & 914, where he used a "spinner" or something like that to make the fan rev at about 1,4 instead of straight 1. Might that be it ???

(At the time I coulcnt relly follow him, as I/we did not have these problems most likely due to less ambient temps around here. So I never kept track of if he ever got it working.)