[Massive Type IV]

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.