CIS Gurus - Help me Safely Inject my Hot Rod 3.0

[1980SC]

All the fiddling in the world won't matter if the FD doesn't supply enough fuel with the sensor plate fully deflected.

True, but have you pulled all six CIS injectors and lifter the sensor plate all the way? It sprays a tremendous amount of fuel. I'm guessing plenty for a built 3.0L.

The key is to get the sensor plate to lift higher than it would stock, so you lower control pressure.

Rob
1980sc

[dd74]

Originally posted by tsuter
I run the stock CIS and use a single supplemental fuel enrichment injector(CSV) aka Callaway Microfueler set to open at 3.0 lbs of boost. Used to run two of them - one at 3.0 lbs and one at 7.0lbs. That setup was producing about 300-315 HP at 9.0 lbs of boost. Stock CR and cam single plugged for 78SC 3.0.

If you have the lambda loop o -sensor you cut it out at 1.5 lbs of boost and run open loop under boost and then restore when boost falls below 1.5 lbs.

Tsuter: this sounds very interesting. Can you give more detail about how this is set up, and also how might it act with RFNG's turbo kit for the 80-83 SC, that he's talked about on this BBS?

BTW: I have no lambda unit set up on my engine.

Thanks.

[tsuter]

Lots of details on this link:

911SC Turbo

I will update it soon as I'm putting several things back together now and will put a comprehensive list of all the turbo setups when done.

[1980SC]

I did a little flow testing by sticking all 6 injectors in a bottle and lifting the sensor plate to it's max height for 60 seconds.



I did it twice and got 41 oz of fuel in 1 minute both times. That works out to 19.2 gallons per hour at the max flow rate. This is with the low compression non-lambda style fuel distributor (USA '78-'79 and euro '78-'80.) System pressure was 74psi.

If someone with the euro '81-'83 fuel distributor would try this, it would be neat to see the difference. I'm sure the quantity of fuel will vary with the condition of the injectors, but mine seem to flow well.

Rob
1980sc euro

[dd74]

Tsuter: I sent you a PM. Please respond when you can.

Thanks.

[1fastredsc]

Hmmm, you think that maybe that micro fuel thing used with the turbo described could be used for this gentleman's application. Instead of responding to boost, it would respond to WOT, via the switch that the lambda computer uses. Something to think about. Although i'd assume using a euro WUR or 78-79 wur would probably be easier and cheaper.

[kstylianos]

Rob,

Interesting test. There is no doubt that the fuel distrib (euro or US) will deliver enough fuel, its getting the control pressure down enough to richen the mixture when needed. Its easy to do this with the k-basic systems (modding the WUR) but this will be the problem with my 82 k-lambda as control pressure is a function of the frequency valve. I was told by EBS yesterday that they were able to disconnect the 02 sensor, richen the idle CO to 2-3% and this change would stay linear throughout the RPM range, even at WOT. They've had luck using this procedure on 30-->3.2 upgrades keeping stock CIS with k-lambda.

So much advice, differing opinions, etc. I'll probably keep it stock to begin with during break in. I'll richen the idle mix CO and decrease the control pressure to the lower end of the range. After break in I'll take it the the dyno for the actual results. If it shows lean, I at least have options (backdate). Probably rig up an A/F meter in the cockpit for a general idea of the mix throughout the range.

BTW: I called to speak with Dieter at Andial, but hes out till Monday....a 3.7, 400+ hp using CIS

I'll keep you guys posted.

[Wayne 962]

You shouldn't have a problem, this motor has been built many times before with good success (that's why it ended up in my Pick's section). I'm missing your argument as to why you need to increase fuel flow? The air pumped in and out of this engine would be exactly the same with your new setup as the old setup. Therefore, the air fuel mixture will be the same as well (theoretically). Steve's comments on Rennlist were directed at someone who was doing all these mods, *and* increasing displacement. I have indeed heard of problems running the 2.7 CIS on 3.0L motors - the one I know of never ran correctly.

My advice is to build the engine, and spec it on a CO meter when it's done. At that point, if you have problems, you can address them then...

-Wayne

[John Desmond]

Why not go for a digitally controlled fully programmable CIS engine management system, that is, with maps and data tables (ignition, injection, lambda...) preconfigured for your specific your application 911 SC, 930 ? Check out the product descriptions on the porsche section of www.lenzmotorentechnikusa.com.

John

[dd74]

John - your link goes to some web/e commerce development service - i.e. not Porsche related...

[emcon5]

Originally posted by dd74
John - your link goes to some web/e commerce development service - i.e. not Porsche related...

Takt the "." off the end of it.

http://www.lenzmotorentechnikusa.com/LenzPowerKatPorsche.htm

[John Desmond]

Thanks for the correction !
The link was going to my web hosting service
because of the "." !

www.lenzmotorentechnikusa.com

John

[kstylianos]

John,

Out of curiosity, how much $$?