75eleven

Will a fuel dist. from a 1977 911 work on a 1979 SC 3.0 litre? What adjustments would be needed to be done if it will work to compensate for the larger engine? Any info would be appreciated.

Bill Verburg

Back in the days when SCs were new the fuel distributor for a 76/77 Carrera 3.0 was often touted and sold as a performance enhancer. Don't know if it is or not but it will work. I have recently spoken with a few owners of SCs with 98mm pistons and 964 grind cams who either have or are planning on using the 76/77 C3 f/d.

Steve Weiner-Rennsport Systems

Hi:

I would NOT use a 2.7 FD on a 3.0 CIS motor. These 2 items have very different fuel delivery curves.

Use an SC FD or the Euro Carrera 3.0 one.

Bill Verburg

Hey Steve,
We're working on a friends 83 SC, 98mm Mahle 9.3 CIS top pistons, 964 grind cams. Stock CIS, its going lean mid to top, any suggestions besides the f/d(thats already on order)?

Steve Weiner-Rennsport Systems

[quote]Originally posted by Bill Verburg:
<strong>Hey Steve,
We're working on a friends 83 SC, 98mm Mahle 9.3 CIS top pistons, 964 grind cams. Stock CIS, its going lean mid to top, any suggestions besides the f/d(thats already on order)?</strong><hr></blockquote>


Hi Bill:

LOL,....I'll bet it IS going lean,......this is SOP with such a configuration,...

The displacement increase, cam change and compression increase all conspire to require more fuel than your system is able to deliver. You can make certain that your warm control pressure is on the lower side of spec (richer) and enrichen the idle mixture adjustkment for 4-5 % at idle.

It will be pretty rich at idle to to prevent the mid-range and top end leanness and this is a characteristic of these FI systems.

Whn you get the Carrera 3.0 FD, you should set it up on a load-type chassis dyno (Mustang) and a 4-gas.

You might need to check and adjust control plunger height to get enough fuel into the thing to prevent cylinder head temps and EGT's that are too high.

Hope this helps.

Bill Verburg

Steve Thanks!
I was wondering about 930 injectors and a little more fuel pressure?

Roland Kunz

Hello

Not direct but using a unit from a higher HP engine in a lower HP engine works mostly good and has no risks. Vice versa also works somehow but sometimes not to good.

Grüsse

Steve Weiner-Rennsport Systems

[quote]Originally posted by Bill Verburg:
<strong>Steve Thanks!
I was wondering about 930 injectors and a little more fuel pressure?</strong><hr></blockquote>


Hi Bill:

Roland offered some good advice there but as you know, there are few other higher powered, K-Jetronic 6-cylinder cars from which to choose from. Even the 930 FD was adapted from a M-B V8 car.

I am not sure exactly what 930 injectors will do in this application. I do not have the specs on their opening pressures and flow rates at hand.

Understanding that system pressure and control pressure in CIS systems are quite different, you may lower control pressure to richen the system somewhat uniformly. This can be changed slightly by shimming the pressure relief valve on the side of the FD. You will need a CIS system tester to do this properly.

Raising system pressure will not do the same thing and can really cause some major grief. As CIS FI system pressures operate in the 70-75 psi range, its tough to raise that without trashing the way the whole thing starts & functions.

Bill Verburg

Thanks again, the CIS injector flow rates have been impossible to come by so far. Plenty of date on the Motronic though.

Roland Kunz

Hello

Ups the time lag.

Best way when upgrading the SC system is using the euro 204 HP unit.

I know a Bosch engeneer who used a Mercedes KE3 unit on his SC. Works very nice with the catalyt and you can rich it up and chocke it down with the lambda sensor. Now his goal wasn´t total power but full monitoring & tunability over the electronics.

( Well finally using a lambdasensor and a voltmeter helps to find out if your engine runs lean under WOT and to pretune the system to save on the expensive dynoruntime )

Higher fuelpressure will not gain to much.

Best way to enrich the system is like Steve said.
Shim the plunger, using larger fuel injectors ( Audi Turbo, Mercedes Cosworth 16V ). A good thing on the Porsche are the plastic isolarors in the manifolds. Very easy to turn specific ones on the lathe.

If you go with wilder cams on a daily driver selecting/modificate to the right WUR is important.

Now in germany you have to test the emisions every year and its a "smog ****" system as well.
While your ***** just look if everything is looking like it souhld ours require to run the car a little emisions program on a 4 gas tester.

Grüsse

emcon5

I know this is an old thread, but I have a dumb question. Will the Carrera 3.0 or late Euro SC FDs work with the Lamda CIS from a later US SC?

Bill, How did you determine your friend was running lean up top? Did he dyno his engine?

Thanks,

Tom