Alan 91 C2

I installed a 1986 turbo engine in my 87 951. I went through the complete engine for wear spec. All good, reworked the head, and all new seals. I also installed the 4 degree advance key for the cam.

The engine has SOO much more low end grunt, and less shake than my turbo S car. Can this be the cam key? Have stock AFM with 3 bar FR. (I modified the ECM chip for the 3Bar)

Albert replaced my turbo, and all seems well.

refresh951

The key did more for my NA than anything else.

Alan 91 C2

Thanks Shawn, for the confirmation.

Thom

I noticed a dramatic increase in low end torque by advancing the 9R cam by 4° (8° crank) on the 3L. So dramatic that the engine knocked like crazy at higher rpm, and the later adjusted tune made for a top end lethargic enough to justify getting back to the stock cam timing.
Probably still a worthwhile mod for folks who enjoy driving their cars like a truck or a turbo diesel.

Paulyy

My top end stayed the same. slightly more lower end torque. turbo spooled slightly quicker. but power on boost dropped bottom end until 4500rpm.

this was on current set up with aftermarket cam.

V2Rocket

going +2 advance gave my NA +4rwhp/+7rwtq

so 4 should be great!

As far as lost top end, there wasn't any by 6000rpm anyways so what's the loss

eman930

I did the 4 degree advance on my 1986 951 with the 9R cam, quicker spool, solid mid power, and didn't feel a drop off on top end