CIS + Big turbo = too lean. Advice for more fuel?

[JFairman]

I have the stock pump in the rear with the 044 in the front.

With the 20% over CIS Flowtech modified fuel head and Brian Leask adjustable control pressure regulator and running 1.1bar and sometimes a little more than that on 10% ethanol 93 octane chevron gas it's getting plenty of fuel.

Any more fuel would be too much and I'd have to raise control pressure to lean it out and that would also make it so the air flow meter plate wouldn't open as far under boost as it is now which means more intake air restriction through the air flow meter housing, even slower CIS throttle response, and less air for the motor under boost.

The turbo would be spinning faster trying to suck air through the smaller more restrictive opening in the air flow meter and that would heat the pressurized intake air even higher and wear out the turbo faster, and would also mean higher vacuum in the air intake down pipe and in the intake side of the compressor housing and behind the compressor wheel at the piston ring type oil seals between compressor side of the turbo and oil filled bearing housing which could cause oil to get sucked past the oil seals and blown into the intercooler and intake manifold.

If my fuel head and CPR were still stock and and it was still going leaner than 12:1 AFR under 1.1bar boost at times in different gears then a higher flowing 044 pump in the back would be a good thing.

This is a little off topic but I also have a nice 200psi "cooling mist" water injection system with an M5 water injection nozzle in the Kokeln intercooler pipe above the throttle body installed and working.

At the moment there is around 30% industrial grade pure methanol mixed in with the tap water I'm using in the cleaned out origonal left front fender well 2.1 gallon washer tank resorvoir for it, and using the mechanical adjustable boost pressure switch that comes with the kit it currently turns on the water pump at about .7bar boost.

I should try adjusting it down to come on at .6bar as long as there is at least 30% methanol in the water and see if that works well without bogging down the motor a little when it first turns on.
I have the water injection boost switch mounted with velcro in the dashboard cavity behind the VDO mechanical boost gauge in the origonal clock location so it only takes a minute to pull out the boost gauge, reach in and adjust it with a small allen wrench around a 1/4 turn counterclockwise at a time untill it turns on the pump at .6bar
I can turn on the water injection pump manually regardless of boost to cool the intake manifold a little or test that it's working at any time too.

If I was going to track the car I'd mix in at least 50% methanol for the temporary octane boost from it.

A progressive water injection controller would be a nice upgrade but there is no misfiring or bogging down when it turns on now so it seems I don't need it and they are expensive and one more aftermarket questionable quality and consistancy electronic device to eventually go bad. I like keeping it simple as long as it works.

[Ringmaster]

UPDATE: Installed a Bosch 044 pump in the front location (already have an 044 in the rear) - ZERO change in air fuel ratio at idle, cruise or WOT

Next step will be to check the main CIS system pressure and if it is below 6.9bar I will raise it to approx 7.2bar.

[Thierry25]

Originally Posted by Ringmaster

UPDATE: Installed a Bosch 044 pump in the front location (already have an 044 in the rear) - ZERO change in air fuel ratio at idle, cruise or WOT

Next step will be to check the main CIS system pressure and if it is below 6.9bar I will raise it to approx 7.2bar.

Hello

Oh you didn't verify this point first ????

If 6.9 only , you should even try to increase a little more 7.5- 8 ....

Just a stupid question , are you sure the both pumps are working now ? Have you change the stock fuses ? ( the stock fuses may be a little too weak for 044)

[Ringmaster]

Bonjour

Originally Posted by Thierry25

Oh you didn't verify this point first ????

If 6.9 only , you should even try to increase a little more 7.5- 8 ....

Just a stupid question , are you sure the both pumps are working now ? Have you change the stock fuses ? ( the stock fuses may be a little too weak for 044)

I didn't verify the system pressure beforehand for two reasons.
1 - The fuel head just came back from a full rebuild and upgrade at CIS Flowtech so I assumed they had set it up correctly.
2 - Since the front pump was 19 years old I wanted to replace it regardless.
Of course I was hopefully optimistic that it would add extra fuel but in my case it didn't. Perhaps this is because the rear-mounted 044 was already maxing out the fuel flow through one or more of the other CIS components.

The fuel pump fuses are still the original amperage but they haven't blown.

[WinRice]

Have you pulled out the tank strainer (big bolt on the bottom) and checked it? Those things catch all the garbage in the tank.

After driving the car for awhile, leave it running and check the voltage across the battery, then across both fuel pumps. Sometimes bad wiring, fuses or relays can create a voltage drop to the fuel pumps.

[totle]

I would try increasing system pressure.
Stock 930 pumps has been proven to 600 hp by bob holcomb.
I just dynoed my 930 to 505 rwhp with new stock 930 pumps. No issues running too lean.
Bought the 044 just in case, but went well with stock pumps.

[WinRice]

Originally Posted by totle

Stock 930 pumps has been proven to 600 hp by bob holcomb.
I just dynoed my 930 to 505 rwhp with new stock 930 pumps. No issues running too lean.

600HP with the lower system pressure of your EFI system. The fuel volume is decreased when required to run at the much higher pressures of a CIS system.

[NathanUK]

Good discussions here

I would like to know if anyone has checked to see when that bypass in an 044 pump does open?
Do you think that's why there is such a big drop on the graph at approx 7.4bar?
I'm wondering if it opens at 11.2bar.

[Ringmaster]

Stock 930 pumps has been proven to 600 hp by bob holcomb.

Originally Posted by WinRice

600HP with the lower system pressure of your EFI system. The fuel volume is decreased when required to run at the much higher pressures of a CIS system.

Exactly! My Holcombe-built 600hp 3.3L EFI engine used a single 044 pump.

This CIS powered sub-500hp car is proving to be a bit more challenging

[JFairman]

Along with everything thats been said already you can also send your fuel head back to Larry Fletcher and he can adjust it for up to 25% more fuel flow up top which seems right if your making 500HP and it will still run really well with good afr's at low and middle speeds with some adjustments to your Brian Leask adjustable WUR.

I know 2 people that have sent their CIS flowtech modified fuel heads back to him to have them readjusted for either more or less fuel after his initial work and he didn't charge anything for that.

Just a thought because I don't think yours is adjusted for much more flow than stock from your descriptions.

[Ken911]

I had the same issue i reset the system pressure to 8.0 bar but that was too high the system isnt designed for above7.4. it performed much better at 7.4 bar and i had to put an 044 pump in the front.

[Thierry25]

Originally Posted by Ken911

I had the same issue i reset the system pressure to 8.0 bar but that was too high the system isnt designed for above7.4. it performed much better at 7.4 bar and i had to put an 044 pump in the front.

Hello Ken

Did you checked the control pressure (warm + 0.8 bar in the boost line) while you did the test under rest system pressure @ 8 bar ?

In my case ( with my AIC), I can adjust the PC to wathever I like .... but with simple WUR, this is maybe not the same story.

[krasuskyp]

Nathan... where you been? Haven't seen you post at all in over a year it seems? Good to see you around / back

and now back to your irregular unscheduled deprogramming...

[WinRice]

Originally Posted by NathanUK

Good discussions here

I would like to know if anyone has checked to see when that bypass in an 044 pump does open?
Do you think that's why there is such a big drop on the graph at approx 7.4bar?
I'm wondering if it opens at 11.2bar.

Nathan, where have you been?

Just guessing here, but either the bypass opens at 11.2, or the pump blows the fuse or burns up due to the big spike in the current draw.

[NathanUK]

I think I got Porsche'd out!

Drove my 3.2 Carrera a few weeks ago after 18 months, they need more power

[Ringmaster]

UPDATE

I raised the system pressure from 6.8bar to 7.4bar. This has put me right on the edge of where I want the AFR to be at 6000rpm+ but now now the car "runs on" for a moment after the key is turned off

Is there a known fix for this besides lowering the system pressure back down to the factory spec?

[Thierry25]

Originally Posted by Ringmaster

UPDATE

I raised the system pressure from 6.8bar to 7.4bar. This has put me right on the edge of where I want the AFR to be at 6000rpm+ but now now the car "runs on" for a moment after the key is turned off

Is there a known fix for this besides lowering the system pressure back down to the factory spec?

Great to know this ! Good job !

On C2T, this is perfectly normal , when you turn off the engine , it continue to run few seconds ! ( The purpose is to fill out the plenum of any unburnt fuel )

[JFairman]

not sure on your car but on a 911 or 911 turbo it's easy to disable the ignition delay relay.
if the ignition delay relay is the same, has the same wires going to it, and is located on the rear relay panel in the same position as a 911 turbo you can try this or ignore it.

1. remove the relay (one small screw) and pull off the plug, you won't be putting the plug back on the relay.

2. if it's the same as a 911 turbo you can make a short jumper wire with a male spade terminal on each end and jump the 2 female spade terminals in the plug that are closest to the fan housing.
thats it, just put some eletrical tape over and around the jumpered plug and tuck it back through the hole into and under the relay panel.
when i did this i remounted the relay to the panel because it's a good place to store it if you ever want to use it again and it covers the hole in the panel under it.

the wires you would be jumping on are both red with a white stripe and one is thicker than the other. you can also strip back some insulation and solder a wire between those 2 wires.

did you ever try lowering boost enrichment control pressure about 1/4 - 1/2 turn clockwise with the little tool Brian Leask supplies with the adjustable WUR modification?
it doesn't cost anything to try it and it will give more fuel under boost with no negative side effects.

[Ringmaster]

Originally Posted by Thierry25

Great to know this ! Good job !

On C2T, this is perfectly normal , when you turn off the engine , it continue to run few seconds ! ( The purpose is to fill out the plenum of any unburnt fuel )

Before I raised the system pressure to 7.4bar the engine would stop dead the instant the key was turned off. It honestly doesn't sound normal to me. After the key is turned off the engine runs, sputters and then stops.

I found this in another thread: "I shimmed my FD to raise SP to 6.2 bar. Anything above this caused the run-on you mentioned. BL recently rebuilt my WUR and was set for 1.7 bar CP and 3.85 WP which caused the run-on again. I lowered WP to 3.7 bar and the run-on disappeared.

So what I can determine is if MY SP (FD) or WP (WUR) is raised any higher the 1-2 second run-on is present. Whether this is a FD wear issue or just the way they are I am not sure."

[Ringmaster]

Originally Posted by JFairman

did you ever try lowering boost enrichment control pressure about 1/4 - 1/2 turn clockwise with the little tool Brian Leask supplies with the adjustable WUR modification?
it doesn't cost anything to try it and it will give more fuel under boost with no negative side effects.

Yes. I went from the BL setting (2.9) down to 2.8 and then to 2.4. The WOT AFR above ~5500rpm really didn't seem to change which lead me to believe there was a deeper issue with the fuel delivery system, i.e. a restriction or the pumps couldn't deliver enough fuel.