SC engine upgrade questions...ones with hotrod SC's please respond...

[emcon5]

We have 2 dyno examples of cam changes on CIS 3.0 engines, from Noah and Mikez.

Both engines have higher compression pistons (Noah, 9.5:1, Mike 9.8:1 assuming stock ROW compression) with 964 cams and early exhaust. Noahs was 203HP at the wheels, Mike's is 224hp at the crank. I looked at the charts in Bruce Anderson's book, and the only mechanical difference I see in these 2 engines is the size of the intake ports, 39mm for Noah, and 34mm for mike. Valve sizes and exhaust ports are the same size. I know the fuel system is different, because I remember Noah searching for a fuel distributor.

So how different is the CIS system on a 77 Carrera 3.0 (Noah's car, may it Rest in peace), a 81+ ROW SC (Mikez's 914/6) and a stock US 3.0? Is there anything to be gained from changing the fuel distributor? What is the difference between the 78-79 and 80-83 fuel distributors?

Tom

[Leland Pate]

JE Hi-compression pistons, balance all rotating parts within like 2/10ths of a gram, a good street grind on the cams, 40mm IDA Webers a set of SSI exchangers and dual in/dual out muffler.

What more could you ask for?? ") Well, that's what I dream of anyway.

[Kahuna]

Bill V.
Great thread lots of good info!

Steve W.
What size wristpin are you using with your 100mm pistons? What other mods did you have to do?

Anyone in Calif.
How do you get away with the wild mods being posted?

[Joe Bob]

Bit of clarification.....my 224 hp dyno results at the crank was on my 3.0 in my current euro spec 911. It DOES NOT have the 964 cams, only SSI and dual inlet/out muffler and no smog pump......this engine only has 60K on it and I don't plan on pulling the motor until I have too.....

My 914/6 3.0, had the 964 cam upgrade. I did not do a dyno on that car and have since sold it....it also had a euro spec 3.0 with CIS....headers, bumped up compression etc.....

[rattlsnak]

http://www.members.aol.com/rattlsnak/ignfuel1.jpeg

3.0 SC, 964 cams, B&B headers, electromotive fuel and crankfire ignition = @250 HP

[emcon5]

Mike, Thanks for clearing that up. When you posted the 224 number on another thread, I dug through the archives to see if I could figure out what you did. Looks like I got your cars confused. My bad.

Still, 20HP from an exhaust change is pretty good, especially when your engine has the smaller intake ports (like mine).

Noah, the fact that you had a 2.7 fuel distro on your car tells us something about the capabilities of the fuel system. I don't have the book in front of me, but the most power from a 2.7 CIS car was what, 170HP at the crank? That you were able to get an extra ~60HP (conservatively, maybe as much as 70) more than the system was designed for, makes me think the 3.0 CIS system should be capable of providing the fuel needs of a 250HP engine without any difficulty.

This raises another question, is the later 80-83 CIS system with Lamda as flexable as the earlier systems?

Tom

[911nut]

Tom,
The idle mixture can be adjusted on the lambda system just like previous systems but the lambda computer will always lean the output of the fuel distributor back to 14.7/1 air/fuel ratio for low emmisions. I believe that John Walker suggested adjusting idle mixture to 3% O and leaving the O2 sensor disconnected for improved performance. However there are some who say this will degrade performance. I'm going to try this next spring.

[Wrecked944]

82SC writes:

5. Induction system CIS vs MFI vs Webers vs ???
I know the CIS is not made for power...and the MFI are heard to be alot of fun....what are your experiences.

Have you considered an EFI system? There was an excellent thread on this subject a few months ago...

http://www.pelicanparts.com/cgi-bin/vb/showthread.php?s=&threadid=10077

A good source of info and advice would be NATCHAMP, his car, the BEAST, can be viewed at his website http://www.mark.hargett.com/

It is a gorgeous car with a pretty slick EFI system installed...the prize, however, must go to stlrj for his 3 litre flat six/Chevy V6 EFI hybrid. Here is what he said in the CIS to EFI Conversion thread...

stlrj
Senior Member

Registered: Dec 1999
Location: Novato
Posts: 421

I did a CIS to EFI conversion on a 78 3.0 a while back and used components off an 85 Chevy 2.8 V6.

What I ended up with was a very responsive, powerful and fuel efficient 3.0 that included all the "on board diagnostics", hot film mass air flow sensor, head temp sensor, throttle position sensor, computer controlled HEI ignition, Bosch injectors, complete wire harness, etc. all for less than $150 from the local boneyard.

I'll post some pictures of my modified intake manifold and air box later.

Fun winter project

Joe Garcia
86 Carrera
Redwood PCA since 1976


I understand Ben Willis is in the process of doing a DIY EFI conversion to his SC. No doubt he knows a lot as well.

Good Luck !!

[Lawson]

Seemed like a good thread to attach an outline of my power upgrade project.

Swap a 3.2 litre into my 78SC. Motor will have PMO carbs, single plug-electromotive, 10:3 or 10:5 comp JE pistons,elgin cams, new valves, rods, springs etc.. headers and a sport muffler. Hopefully good for 280-290HP. Should be ready for next seasons DE events!!

[Don Wohlfarth]

Originally posted by 82SC

It will be interesting to see what kind of answers you get to your questions.
Don Wohlfarth

Here is an email I got (with a first line change... ) Don knows what I mean...see edit to 1st post...

Everyone seems to be dancing around the the question of what to do and still keep the car so it is streetable and emissions legal.
My suggestion would be to find a tired 3.2 that needs rebuilding and sell the 3.0.
Cost of rebuilding 3.2 would be similar to 3.0 so that's somewhat of a wash. Install the 98mm p&c's and put it back together.
You'd end up with a 3.4 with Motronic and the motor would have Carrera tensioners. Cam choice would be a wash between 3.0 vs 3.2.
Main cost difference would be between cost of 3.2 and selling price of 3.0.
Motor would still be close to "stock" for emission issues, you've gained 24.4 cubic inches, and you've improved the fi from CIS to Motronic, and best of all you've accomplished your objective of rebuilding your own motor.
Yes, you can cobble something together with 12:1 pistons and racing cams and spend the next 5, 7, 10 years with it parked because you can't pass emissions.

[Stackett]

I have just recently became a Proud Pappa of a 80 SC Targa in need of a rebuild and am new to this wonderful outlet/resource of info. I had every intention of using 9.8:1 pistons and 964 Cams, but have noticed that some are suggesting using 3.2 P&C. Will this work with the CIS and are there any other mods that I might have to make in order for them to work? Also will the 964 cams still help out on the ponies on the higher end of the RPMS?

Any info would greatly be appreciated and I have started reading Bruce and Waynes books on rebuilding for this project.

[1fastredsc]

If emissions stay, 3.2 P&C's with 64 cams, open exhaust (same as you have). That should give it some all around good kick.

No emisions, 3.2 P&C's, head work or 3.2 heads, S or better cams, some twm stacks, tech 3, twin plug.

No emissions or money limit, over bore 3.4 with the short stroke, twin turbo's like some garrett gt turbos, custom intercooler with a 3.2 intake, and whatever else i can't afford.

[1fastredsc]

If emissions stay, 3.2 P&C's with 64 cams, open exhaust (same as you have). That should give it some all around good kick.

No emisions, 3.2 P&C's, head work or 3.2 heads, S or better cams, some twm stacks, tech 3, twin plug.

No emissions or money limit, over bore 3.4 with the short stroke, twin turbo's like some garrett gt turbos, custom intercooler with a 3.2 intake, and whatever else i can't afford.

[Randy Webb]

A lot of these hp figures seem optimistic for a street engine.

I agree you will be $$ ahead if you just get a 3.2L to start with. Then you don't have to get the heads, you'll already have them. Putting a 3.2 crank into a 3L is a lot of work and $$.

As Bill V. said figure out what you want first, then repost.

You may want to just put in a stock 3.2L now and modify it as the you hit the smog relaxation time period.

BTW, I'd bet money that twin-plugging will reduce emissions.