Anyone running 3.5L 964 cams with CIS?

[flightlead404]

Gents

I'm considering some slight tweaking and wanted to see if anyone is running a similar setup AS A STREET CAR and wanted to get driving impressions. This is 1986 US 930 stock fuel head, lines, injectors, CIS with FrankenCIS managing the mixture via the lambda valve.

-3.5L 8:1 compression
-964 cams
-Lightweight clutch
-Ported intake (heads, injectors, manifold to match) possibly as much as 40mm
-1.2 bar w/g
-K27/29 hybrid
-Twin plug w/distributorless ign, COP in a wasted spark config
-Stock exhaust port
-RarlyL8 headers + hooligan

If anyone has done anything similar I'd like to head impressions on driveability, and gotchas you ran into, or would-do-it-differently-next-time's.

Thanks

[Black_Hat]

those mods will require the fuel head be opened up for more flow

How much ?

put the motor together run conservative boost and carefully do some runs and get an AFR graph boost/RPM
see where and when it goes lean
take that info and send it with fuel head to RarlyL8 with a description of where you want to be

the motor confg above will scoot

[flightlead404]

Originally Posted by Black_Hat

those mods will require the fuel head be opened up for more flow

Will it? Possibly, not sure about that. Using the lambda valve and FCIS I'm able to get much better control of the fuel than the old rube goldberg modified WUR+RPM based Pierburg switch, and especially with FCIS control of control pressure expect to be able to deliver more fuel as well. Maybe I'll need to do some system pressure tweaks and I'll definitely be monitoring and logging system pressure, control pressure, and AFR.

But yes, that's my planned approach. Just want to get an idea of what its driveability as a street car will be first.

[Black_Hat]

wide open Is wide open, no matter If a WUR or a FCIS Is controllIng
there Is a max for the black fuel head and a max for the aluminum fuel head and from experience that max varies. There Is a HP range you are limited to with safe AF under boost for each fuel head --I'll let others chime
In on that one.

I have a similar build minus : 3.5 mine s 3.3 , Stock compression

and the following differences:

turbokraft turbo S cams ,
WUR,
modded aluminium fuel head
K29
XDI 2 twin plug

My turbo Is street able In heavy traffic , with A/C and..........It Is a Rocket
It stats hot & cold eve time. It pulls clean from Idle to full boost every time

http://forums.pelicanparts.com/911-930-turbo-super-charging-forum/767012-forced-deal.html

[jbrown]

I have basically the same build. The only difference is gt35 turbo, single plug and EFI. I did own the car when it was CIS. It originally had sc cams and I went to 964. That is a lot of boost for CIS if you ask me. I can almost guarantee you will not get enough fuel with that much boost and the size of the motor , even with the fuel head modifications. I could not get enough fuel running 1 bar. So I bit the bullet and went EFI. Even with CIS I got full boost between 2800-3000 rpms, and the car was great. I really did not want to deal with the headache of the fuel head anymore so I went EFI best thing I did. If you are going to buy a turbo I would definitely go with a gt35. I had a K27HF and there is no comparison compared to ball bearings.

[TurboKraft]

That setup on 0.9bar boost on CIS injection -- 394.3whp/377.9wtq.
The only thing that kept Rick's engine from making more torque and HP was the Euro CIS being maxxed out.
And, with no adjustable WUR, we couldn't (easily) fix the typical 10:1 AFR dip which detracted from the torque.

You have the advantage of having the electronically-controlled frequency valve to correct the AFRs, but you'll ultimately need more fuel. Short of adding a piggyback fuel injector, I anticipate you will need to have your FD set up for max fueling, more than simply adjusting the individual trim screws on the FD.
CIS Flowtech's "007" distributor mod would not apply as that eliminates the frequency valve. You'll have to ask him if he has any other tricks to get more fuel throughput.


Edelweiss Motorsport in Germany can also modify the fuel head, similar to what the factory did on the 934's, including machining the metering slits and piston, but it is very time-consuming and expensive.
We have one of his 934-style modified airflow meter plate assemblies and it is very nice indeed.
They offer all 3 major components -- airflow meter, fuel distributor, and warm-up regulator -- as a complete 934 fueling system for approx. €10k/exchange (plus shipping and associated import fees).

[flightlead404]

Originally Posted by TurboKraft

That setup on 0.9bar boost on CIS injection -- 394.3whp/377.9wtq.
The only thing that kept Rick's engine from making more torque and HP was the Euro CIS being maxxed out.
And, with no adjustable WUR, we couldn't (easily) fix the typical 10:1 AFR dip which detracted from the torque.

You have the advantage of having the electronically-controlled frequency valve to correct the AFRs, but you'll ultimately need more fuel. Short of adding a piggyback fuel injector, I anticipate you will need to have your FD set up for max fueling, more than simply adjusting the individual trim screws on the FD.
CIS Flowtech's "007" distributor mod would not apply as that eliminates the frequency valve. You'll have to ask him if he has any other tricks to get more fuel throughput.


Edelweiss Motorsport in Germany can also modify the fuel head, similar to what the factory did on the 934's, including machining the metering slits and piston, but it is very time-consuming and expensive.
We have one of his 934-style modified airflow meter plate assemblies and it is very nice indeed.
They offer all 3 major components -- airflow meter, fuel distributor, and warm-up regulator -- as a complete 934 fueling system for approx. €10k/exchange (plus shipping and associated import fees).

Hi Chris, this is Martin in Atlanta. We talked about this car the other night and as I understood the conversation you indicated I probably would be OK wrt to fueling. This post seems to contradict what I took away from our conversation (and I was surprised to hear you say what I thought I heard you say).

So, what should be reduced to juuuuuuuust get under the bar so to speak? Lower boost? 3.4L instead of 3.5L? Diff cam?

[TurboKraft]

I missed the "1.2bar" during our conversation. :-\
Cool at lower boost levels.
More boost will most likely require more fuel.

The controller you're using is Microsquirt-based, correct? Are the pulsewidth output channels independently programmable? If so, it would be easy to add 1x additional injector to the system.
Just an idea.

[flightlead404]

Yes and yes. There are several channels, but the FCIS uses one optionally two. The primary one controls the lambda valve, but the optional second one in the eWUR controls control pressure. So, dropping control pressure to the min and increasing lambda to the max is what I need to measure.

Lower meaning .9 bar?

How do I calculate the amount of fuel needed at 7,000 rpm and 1.2 bar for 10:1 AFR?

Estimating using .6 BSFC and 450hp I'm swagging a shade over 17,000 cc/min. Seems high. Anyone got a better formula?

Anyway I can easily rig up a circuit to let me dial up different duty cycles for the lambda valve and eWUR injector, stick my injector lines in some graduated baby bottles and gather enough data to make some plots to determine achievable fuel flows. In fact, I might do that this weekend.

The setup we discussed, and using my FCIS to control fuel and the twin plug ignition is practically EFI anyway. Chris, don't make me go full EFI with ITB's 'cos then you'll tell me I'll need bottom end work, and transmission mods, and on and on and on....... :-D

[Tippy]

Just going to throw this out there, but when I read the specs and saw the pictures, I figured there was no way in hell CIS will hang!!! Totally going off of what yiu guys have said.

Just EFI it and get it over with! It's not my money after all! �� �� ��

[kevin930t]

Chris,when you aay piggy back injector are you referring to the old andial fuel enrichment system or something similar?

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[TurboKraft]

Remind the audience what you have for a transmission and clutch, please.

Kevin -- no, I mean adding an electronic fuel injector in the outlet of the intercooler ala Miller-Woods, one of those old supplemental injector enrichment systems that used a standalone injector driver. Low tech, but effective.

[flightlead404]

Originally Posted by TurboKraft

Remind the audience what you have for a transmission and clutch, please.

Kevin -- no, I mean adding an electronic fuel injector in the outlet of the intercooler ala Miller-Woods, one of those old supplemental injector enrichment systems that used a standalone injector driver. Low tech, but effective.

This thread is going to get funner and more expensive by the minute lol

Its a stock 86 california 930 with all emissions removed, 83k miles, K27/29 Brians headers and a hooligan. Clutch is slipping on boost, time to do something. Currently Microsquirt based FrankenCIS controlling lambda valve with stock WUR in place, but I have the eWUR block and injector as well, just didn't need it for current setup.

Like I need you guys to help me spend money haha but wth, my daily driver (510hp Jag XKR coupe) is making my 930 feel a bit anemic :eek!

[RarlyL8]

We use SC cams for street cars to put as much torque in off-boost as possible. They are a terrific improvement. 964 cams will slide the torque curve to the right a touch which also adds power up top.
As for fueling you are past what a Lambda laden -145 USA FD can handle. Don't know what the FrankenCIS is capable of but it can't produce more fuel than the FD will supply. The -007 mod is needed for that. If the FrankenCIS can work stand alone without Lambda that would be worth a try. I don't like add-ons that spray fuel in the manifold as the runners are not a tuned path to each cylinder so will not properly distribute the fuel. Yes they will work by just dumping gas but there or better ways to supply adequate fuel to meet the needs of the engine.

[Tippy]

Originally Posted by TurboKraft

Remind the audience what you have for a transmission and clutch, please.

If you have already delved into Microsquirt, just ditch the CIS and make it fully EFI.

You weren't scared to try partial EFI, so take it all the way!

You already have the MicroSquirt, so there's that....

[flightlead404]

Originally Posted by Tippy

If you have already delved into Microsquirt, just ditch the CIS and make it fully EFI.

You weren't scared to try partial EFI, so take it all the way!

You already have the MicroSquirt, so there's that....

Partial EFI is easily reversible. And cheaper.

I'm looking to basically get all I can get from CIS+FCIS.

[Tippy]

Originally Posted by flightlead404

Partial EFI is easily reversible. And cheaper.

I'm looking to basically get all I can get from CIS+FCIS.

Done right and thought out well, any EFI system can be easily reversible too and save the CIS for later.

Just needs to upfront planning.

[flightlead404]

Originally Posted by Tippy

Done right and thought out well, any EFI system can be easily reversible too and save the CIS for later.

Just needs to upfront planning.

Essentially I would need a Carrera manifold, and adapter set, and a set of injectors beyond what I'm already planning, right?

Will the new manifold place the throttle body in the same position allowing me to use my current intercooler?

[Tippy]

Originally Posted by flightlead404

Essentially I would need a Carrera manifold, and adapter set, and a set of injectors beyond what I'm already planning, right?

Will the new manifold place the throttle body in the same position allowing me to use my current intercooler?

Nope. Chris makes injectors blocks that go under your pancake intake.

Throttlebody will not move.

[kevin930t]

After months of talking with the red devil sitting on my shoulder,saying just do it what do u got to loose.I am really starting to think efi.I mean seriously what benefit is keeping the cis?

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