My winter project here in Montana is to change out the exhaust, turbo, wastegate and cams on my 87 930.
I'm putting on GHL headers, K27-7200 turbo, 962 waste gate. Right now the 3.4 twin plug 8.5 to 1 compression engine has Group B cams (no low end at all) don't know why the previous owner (A Doctor who did no racing) used these, the low end is just not there.
Sooo.... any suggestions for better low end???
SC cams vs. ???
Thanks, Randy

 

I personally like the 964 cams over the SC cams and think they will be better matched with the quicker spooling K27. I have heard that the SC cams will give you a bit better low end compared to the 964 grind, but with your 8.5:1 compression, I really wouldn't worry too much.

 

You should be eliminating a lot of lag with the higher displacement and especially with the 8.5 compression. The group B cams are good from 5000 to 7000 rpm so basically you'd have power thru out the rev band. I'd leave it as it is. Off course unless you did'nt have the higher compression and displacement, than you should go for the 964 cams.

 

You are going to have a totaly different car w the SC or C2 cams, K27-7200, headers and your 8.5 CR.

You might miss the top end pull though as it will not blast through redline like your current setup wants to. You may finding yourself shifting at 6000 rpm for power instead of 7000+ rpm.

Based on what you are used to you might want to go with the C2 cams which will pull great w the new headers & quick spool.

For back ground, the factory had an X33 performance option for the 3.3's which were SC cams w biger ports. Latter w the 3.6 C2 Turbos they had an x88 option that used the C2 cams w bigger ports.

If you change the cams please concider changing the rocker arms or having them rebuilt. Someone before me put C2 cams in my car and it lost a lobe within one year (I now have SC cams in my C2T). You need to look at the valve spring settings, concider replacing w Hi rpm springs, or go to lighter retainers if you go to the C2 cams as they are much more agressive in their ramps over the stock & Groupe B cams. Also might be a good idea w the SC's.

A couple of other things that have effected my car: 1) check your injectors, mine were squirting instead of spraying. Made a differance. 2) check you CBV, mine was bad and it killed boost between shifts creating a lot of lag. 3) go tith a Rice fuel regulator. This will get your mixture up when you first crack the throtle for max off boost torque, alternately you could run it on the rich side. When I do this I do feel a big diff in off boost pull over the smog setting and get quicker spool up to.

I am not an expert. This is just some of the things that seemed to make a diff for me.

 

Thanks for all the ideas everyone. I'm really starting to get confused...ha ha
Anybody ever try the SC330 grind? It's for low and mid range power.
Keith, where can I find out more info on the Rice fuel regulator?

 

Rice wur:

To contact Lee Rice please call 714/539-1042 or Email Riceturbos@aol.com