fasteddie313

How high of a system pressure can/do you guys run when pushing the limits of CIS fuel delivery?
How much can the fuel distributor take and how much before you get into problems with injectors popping off too early? What are the limiting factors and your experiences?

I will be running upgraded fuel pumps, and plan to be able to fully adjust my WUR warm/cold/boost pressures all separately and system etc. yada yada..

Any advice for someone planning to approach the boundaries of CIS for the first time?

I hear you 930 guys are more experienced in these matters than most..

dos531

I run a little over 7bar. It really doesn't help that much to run a higher system pressure if you're out of fuel. If you want more flow youre going to need to modify the fuel head for more volume.

speednme

To add what was previously mention...not just your fuel head but your fuel lines. Especially if you're planning on raising boost. Over on Pelican there is a thread on a digital WUR...it may be of interest to you.

fasteddie313

Thank you, I will put some time into researching modifying fuel distributors next.. I had not considered this yet.

I'm not sure that I'm looking to go that extreme though. It is said that my CIS is good to 250 crank hp in stock form, I am only looking to maybe squeeze another 10%-20% out of it. My current goal is less than 300 hp. I don't need that much nor do I have that much turbo (yet).

I believe I will be doing something similar to this..


But also likely tampering with the boost sensing aspect of the WUR as well..

Any links to modifying fuel distributors or any CIS tuning in general would be great.

Also, what procedure would you recommend for approaching and finding my fuel delivery limits as safely as possible? What to look for on the wideband?
Just turn it up slowly until it won't hold rich to redline anymore and then settle my boost setting somewhere just under that?

Again, thank you..

fasteddie313

Thank you guys for leading me in the right direction!!

I will be going with this fuel distributor..



It is a CIS-E system from 4.2L-5.6L Mercedes (420-560) V8s 86-91

And will be controlled for complete AFR tunability with Microsquirt via a FrankenCIS DPR interface control module from these guys.. http://www.frankencis.com/

I should never have to worry about running out of fuel ever again and gain complete control of my air/fuel mixtures throughout the entire curve off and on boost etcetera with megasquirt's tunerstudio.

I will be running 2 ports per injector (8 ports, 4 injectors) like the factory 924 GTS/GTS clubsport here...


This CIS-E system completely replaces my entire CIS-Lambda system, so I can remove my WUR, Frequency Valve and my entire Lambda system (replaced only by the fuel distributor + electronics) while retaining only my pumps, accumulator, filter, and injectors..

More reading here if you are interested.. http://forums.pelicanparts.com/911-9...rankencis.html
I think this is what speednme was referring to.

They have WUR replacements to completely take control of your control pressure via microsquirt for CIS-Basic and CIS-Lambda systems too, but I need more fuel than my unmodified stock distributor can manage anyway so I figure I may as well go big or go home and convert to a v8 CIS-E distributor..
They have fully tunable CIS solutions like this for any and all CIS versions..

One more question if you don't mind..

What are the biggest baddest CIS injectors you can put on a 930 without modifying the head? Are there any reasonable upgrades in this area to accompany my new massive distributor I will be installing?

As far as I know my 931 injectors are the same (threaded) injectors the 930s use..

This is going to be epic..

Black_Hat

1991 -1992 C 2 turbo 3.3 liter injectors

and

1994 C 2 turbo 3.6 liter injectors are different

they are both threaded as the 930 injectors

the 3.6 injectors deliver slightly more flow BUT are extremely expensive

Black_Hat

3.3 T injectors are bosch 0437 502 017 / Porsche 931 110 225 00
3.6T injectors are Bosch 0437 502 057 / Porsche 964 110 235 20

fasteddie313

I have the "3.3 T injectors bosch 0437 502 017 / Porsche 931 110 225 00" injectors right now, as OEM.. AFAIK they are the same.

After further research I find that the GTS also uses the same injectors siamesed on its factory V8 distributor, so mine should be just fine..

It's good to know that there is an upgrade out there somewhere if I ever find I need it though.

fasteddie313

Thanks guys..

speednme

fasteddie313

Running out of turbo @ 20psi..
This FrankenCIS stuff on a V8 distributor WORKS!!

Attachment 1342206

Mid 10s on top might be a bit too much fuel yet though..

flightlead404

I have pretty extensive experience with the FrankenCIS setup. I have achieved about 400 rwhp with bolt-ons (dyno tested) on an 86 Cali 930.

carrpet

Hi there
I am keen to look at replacing my WUR with the FrankenCIS setup.
Are the details of your installation anywhere I can take a look at ?
Can you help me with sensor requirements etc
Regards
Peter