Cam choice for EFI 3.0

[echocanyons]

I plan to use the TEC3 engine management system with a carrera intake and otherwise stock 3.0 from an 80SC.

Should I consider a different cam profile or would the stock cam be the best choice.

Is there any other things I should consider changing?

[beepbeep]

Best choice for what? It all depends on what your main goal is. If you want hi-power hi-rev screamer then hotter cams could be a good idea. What kind of engine character would you like? Prepared to trade some mid-range torque for more power? TEC will allow you to fine-tune the engine regardless so it's totally up to you! :-)

Post some pics!


P.S. You'll probably see some posts from people from the "Church Of Intake Reversion", claiming that you cannot use anything hotter w/o Individual Throttle Bodies...do yourself a favour and ignore them.

[echocanyons]

No pics now cuz just a long block and other pieces.

I would like reliability, longevity and a modest power increase over stock but still retaining fair to good gas milage.

This engines plan is to be in a driver that sees 2-3 driving events a year.

Also this engine will be in a 914

[dd74]

Beepbeep - what about the otherwise stock 3.0 stuff, such as the CIS pistons? Would the TEC3 make a dramatic difference while still using the CIS pistons? And how radical a cam can be used with CIS pistons along with TEC3?

[beepbeep]

Originally posted by dd74
Beepbeep - what about the otherwise stock 3.0 stuff, such as the CIS pistons? Would the TEC3 make a dramatic difference while still using the CIS pistons? And how radical a cam can be used with CIS pistons along with TEC3?

Well I don't think there are problems tied to use of CIS-pistons with EFI itself. Pistons don't know if fuel has been injected by CIS or EFI. (Tbit'z SC EFI conversiond are running w/o problems).

Only potential problem I can would be piston/valve clearance , depending on lift/duration/timing. It's very hard to answer that question w/o knowing cam specs, and even then it's probably prudent to do a test-assembly and check clearance. Cam seller should have guidelines as well.

(Using term CIS-pistons is somewhat misleading, as 930 pistons are also "CIS-pistons" but their design is totally different from SC-ones- no squish, flat tops)

[914timo]

I have old Solex-cams in my 3,0 SC engine with 40 Webers. I am happy I didnt find S-cams when I was doing my engine. After measuring I had to cut valve pockets to the pistons. The valve/piston clearance IS the problem with any hotter cams than stock with stock CIS pistons.

If you have nicasil cylinders, go and get a set of JE hi-comp pistons. They should have enough valve/piston learance to handle all street cams.

[Wayne 962]

The 964 cams are about the hottest that you can run with the stock pistons. There's also a Webcam with a similar 964-style profile. Without changing the pistons, you can't really run any hotter cams.

As for fuel reversion - you can run a hotter cam, but you can't run a super-hot one without going to individual throttle boddies. Someone like Rick Clewett knows the best configurations...

-Wayne

[echocanyons]

Where could I find the production info on what engine #'s used Nikasil vs. alusil. Waynes book says they used mostly alusil becase of costs but does that mean they used some nikasil?

[Wayne 962]

Originally posted by echocanyons
Where could I find the production info on what engine #'s used Nikasil vs. alusil. Waynes book says they used mostly alusil becase of costs but does that mean they used some nikasil?

There is no data on this - Porsche used what they had at the time. On all engines from the early seventies thru 1989, it may be one or the other...

-Wayne

[emcon5]

There is some discussion of cam choices/limitations with single plenum here.

Tom