CIS HP Hard Ceiling and CIS injector flow rates
 

The consensus seems to be that the hard HP ceiling for a CIS car is somewhere in the 400 rwhp range. My car has many modifications (fuel head, wur, GT 35r, dual wastegate header) and is suffering from the typical fueling problems at high rpm under boost. The fuel head and wur have been opened up by Larry Fletcher at CIS Flowtech (great guy btw) and I dynoed the car recently which put out 325 rwhp at a reduced 'redline' of 4850 rpm. Above that the AFR went beyond 12.5-12.9 and the car ran lean.

Chris Carroll has been a great help in helping me figure out what is going on and the next step is to rewire the fuel pump circuitry and run dual 044 Bosch pumps. I have sourced a set of the larger Euro fuel lines and am considering the 009 injectors. I have searched not only this forum but others and still have the following question:

*****Is there any objective data on the flow rates between the 015 stock US injectors, 009 Euro injectors, and 057 3.6 965 injectors?

It seems that the 009 Euro injectors and 057 injectors are thought to flow more than the US stock version but how do they compare to each other?

Any guidance or tips would be much appreciated. If the Euro fuel lines don't make any difference then I won't bother changing them out.

Thanks!

Have you asked Chris Caroll this question?

I don't think anybody here really knows... The topic has been brought up many times and I can't remember a solid answer... just opinions.

We've seen 450whp on -009 injectors so they can handle the load. I'm not going to waste time comparing injectors, these work so they are all I use.
325WHP can be handled by bone stock CIS so something is going on with your fuel system. Check the pumps, system pressure and flow. Once you get to 400whp tuning gets more involved but the tuned fuel head will easily feed that number with more to spare.

Dirk (Edelweiss) has built CIS motors over 550HP. It can be done, just not easily.

That is a very useful data point, do these builds require the larger Euro fuel lines or do they make any difference?

At 1 bar, are you able to rev all the way to redline or do you have to use a lower redline for safety?

I'm going to redo the fuel pumps with dual 044s and new dedicated wiring.

Thanks very much!


Tonger

Frank, is the full throttle enrichment disk adjusted all of the way out (even/level with the WUR body = lowest enrichment control pressure = richest setting) on your BL WUR and you're still going lean at high RPM?

No Euro lines are not required at 400WHP. The Euro FD or modified USA FD is required. 044 pumps are not required but do help as they flow more than stock so you don't have to increase the system pressure.

Brian Leask has my wur now. I have been working with a wur that was rebuilt and set by CIS Flowtech for my application. ***Do you know the lowest enrichment control pressure that we can run?***. Larry estimated the point of diminishing returns to be around 2.7 bar or so. I'm going to try a manual boost controller between the intake and the wur as a way of delaying the boost signal until the higher rpm range as an attempt to deal with the overly rich midrange.

To be fair to Larry at CIS Flowtech, it really does look like I have a fuel pump issue that I will fix first and then go back to the dyno.

Thanks!


Tonger

Thank you Brian-

Larry modified my fuel head to the max flow rate. Do you have any idea how much effect the euro fuel lines may have in this case?


Tonger

At your power level the lines should have no effect.

have you considered that with the greatly reduced back pressure of the exhaust system that the CIS system really was not designed to deliver the required amount of fuel needed at hi RPM. i dont think it is as much as the system cant put out enough fuel as it is it thinks it is providing enough fuel for hte amount of air coming in.
so really about the only things i can think of is to redsign the AFM or make the CSV open at HI RPM or go with electronic injection.

looking at the NA CIS systems (3.0 sc) you can really see the 3 sections of metering in the AFM. you can see the idle, the mid cruise and then you can see how it gets more narrow for the upper RPM's to richen it up. looking at the 930 AFM i dont really see the 3 sections. i think the 930 CIS just relies on the richening from the WUR.
i may be wrong, this is just what i have noticed in my short time with the 930.

[QUOTEfollowing question:

*****Is there any objective data on the flow rates between the 015 stock US injectors, 009 Euro injectors, and 057 3.6 965 injectors?

It seems that the 009 Euro injectors and 057 injectors are thought to flow more than the US stock version but how do they compare to each other?
[/QUOTE]

On the difference between stock US 015 and 009 i can not say anything...
here can not made a reliable statement for a solution, each system must tuned for themselves.

In the Forum there are measurements between 017 and 057 injectors:

http://forums.pelicanparts.com/uploa...1430746492.jpg

I have made measurements with a buddy between 017 and 009 Injectors =
no difference (unless the difference in price).

Bosch injectors Porsche Turbo

Porsche 930 Turbo 3.3 ROW injector 0437 502 009 Bosch number / 930 110 225 02 (Pet)
Porsche 964 Turbo 3.3 ROW injector 0437 502 017 Bosch number / 931 110 225 00 (Pet)
Porsche 964 Turbo 3.6 ROW injector 0437 502 057 Bosch number / 964 110 235 20 (Pet)

Injection quantity 009 to 017 is equal (measured with 2 different warm-up regulators and Full Heads (EUR). The opening pressure of 009 and 017 are equal too 7.2 to 8.3 bar

Porsche say, the 057 nozzle has about 5% more injection quantity. It can easily be the same or a higher injection quantity with 009 or 017 Injectors with a tuned CIS System. (modified Full Head / Adjustable WUR / RPM CSV Kit)

Difference between the injectors can be up to 10% (say Porsche)

I don't know the answer to that, but more K-Jet knowledgeable people here probably do.

I have never measured fuel pressures - got my WUR modified by Leask long ago, and then tuned it with an AFR meter only.

Just to compare, I too have a turbocharger that claims to blow a lot more air at high RPM than the stocker (an Ultimate Motorwerks K27 HyFlow), and with an unmodified, Lambda fuel head, and original fuel pumps, my problem in the past was too much fuel at high RPM and I've had to lean it out (raise the full throttle enrichment control pressure) in order to not have high RPM, rich misfires.

For the 930 the lowest practical fuel pressure we see on boost is 1bar. Going lower than that can create problems with the WUR.

Hello

More info on you engine would be nice, year , cams , timing, fuel head , flow rate on head , exhaust, intercooler and boost and most important do you have a AFR gauge and CIS fuel pressure gauges ?

You will need those items to be successful

Here's what I have experienced and some suggestions,

Pull your spark plugs after a run and check if they are equal in color, cly 2 and 5 maybe running leaner (and that can be adjusted for also), only if you are useing a larger intercooler and higher boost than stock, 1 check voltage to your pumps, fix or replace wiring. (2) 044 pump up front only and stock in the rear. with two 044 pumps your system pressure will be to high and you will have the reverse side effect and be to lean.

I do recommend using euro fuel lines and 009 injectors. A adjustable WUR is a must, and we can help with that also, Once you provide the engine specs we can help you better with your setup

Helio

You can adjust the system pressure lower! I have run two 044 for couple of yrs @6bar and fuel is enough at hight rpms with AIC1 control on the FD lambda port. I dont know why people say it cant be done like this but on my car it works. Over one bar boost till 7000 rpms and AFR is in check. Mods on sig.

can ^you^ please describe what an AIC-1 is for the ignorant (me)?

I'm running dual 044's as I was running out of fuel past 5500 before and I still am now - have to get around to getting my CIS gauges hooked up and adjusting my BLWUR, but I'd love to hear more on your setup - thanks (sorry to TJ!)...

Paul, the gauges are not needed to adjust for full throttle enrichment (boost), or any of the other parameters, when your current situation is "close" (like yours is now) - using the AFR meter as your tuning tool (aka: your tuning "Paul") works great. Call if you want to discuss making full throttle enrichment adjustments with your BLWUR, bub.

Paul: search for user thierry25 and split second and it should come up. Also Sup from England used to do this With some other controllel but they both used the controller on the wur line. Found it http://forums.pelicanparts.com/911-930-turbo-super-charging-forum/482246-electronic-cis-fueling-boost-control.html

My setup thread is here http://forums.pelicanparts.com/911-930-turbo-super-charging-forum/558825-split-second-aic1-setup-problems.html

I have a spare unit similar to Thierrys ( cabable for boost control which mine does not have). I'm going EFI hopefully next winter so these both might be available then.

0 437 502 002 is set with opening pressure 3.55 bar, and 35 degree spray angle. It has a rubber sealing cuff, and no body thread. It is the '72 to '73 911 CIS injector.

0 437 502 009 is like 0 437 502 002 but with body thread M10 x 0.75, and deletion of the rubber sealing cuff. I believe it is the Euro and US turbo injector from '76 to '81.

0 437 502 015 is not a Porsche injector, but a Bosch aftermarket substitute. It is the same as the Porsche part 0 437 502 017 (see below).

0 437 502 017 has a higher opening pressure range of 3.3 to 3.7 bar, 35 degree spray angle, 1.5mm seat diameter, body thread M10 x 0.75, no rubber sealing cuff. It is the '81 to '92 930 turbo injector in all countries.

0 437 502 057 is the same as 0 437 502 009, but with higher opening pressure 3.3 to 3.7 bar. This is the 964 3.6 injector for all countries.

So, you can see that there is no real difference between injectors. The turbo injectors are actually based on the 911 naturally aspirated CIS injectors.

The 009 injectors have an opening pressure controlled to the nominal 3.55 bar. Flow is proportional to pressure drop when measured across the same orifice. The flow difference between the 009 injector and the worst case 057 injector is ((3.7-3.55)/3.7)*100 = 4%.

The flow is controlled not by the injectors (or lines), but by the metering slit in the plunger barrels, the pressure drop across the slit, and the amount of the slit exposed by the air pressure on the lever arm.
http://forums.pelicanparts.com/uploa...1431225083.jpg

interesting.

at cruise, the injector really would not matter as far as flow, but what about at WOT? is that where the 009 would flow more fuel than the US version? after all for a given amount of air coming into the engine it would only require the same amount of fuel no matter what injector was being used.

also, would the injector really need to be "matched" to the fuel head? the euro head has a lower system pressure than the aluminum US head so then the need for the lower opening pressure for the 009? which i thought goes with the euro head.

are you looking at the opening pressure as the flow rate? (3.7-3.5) little confused on your flow rates.

If you search the thousands of posts on fueling issues with modified engines you won't find one where the injectors were the limiting factor. For our street engines it just isn't an issue.
Matching the injector with the fuel system (not just the FD) is akin to the slightly different warm up times and pressures on the various WUR's. It is an optimization for the operating conditions of the engine type number.

Thanks to Helio for the specific tips. I'm running a GT35r twin scroll at 1 bar with twin wastegates, 964 cams, and a Garretson intercooler. The fuel head has been maxed out by CIS Flowtech and the WUR has been adjusted by them as well. I have a second WUR with Brian Leask to be made adjustable.

Thanks also to SpeedyS for the specific injector data, that was helpful.

Tonger

So can you tell us where you are at on your tuning ? Have you installed the euro fuel lines and injectors ? do you have an AFR gauge installed yet ?

I just got a set of the Euro lines and they are much bigger than the US lines.

Outer diameter: 6 mm Euro, 4 mm US
Inner diameter: 2.75 mm Euro, 2 mm US

I don't know how to upload the pictures but the difference is quite striking. With the resistance decreasing as a function of the radius to the 4th power, the Euro lines have about 1/3 of the resistance to flow that the US lines have.

Resistance to flow is proportional to (viscosity of fluid*length of tube)/radius^4 by Poiseuille's Equation.

Therefore the radius of the US lines are 1mm and the radius of the Euro lines is 1.375.

1 to the fourth power is 1 while 1.375 to the fourth power is 3.57. Using this as the denominator in the equation there is 3.57 less resistance to flow in the Euro lines compared to the US lines.

I am still waiting on my 009 injectors to arrive and have the Bosch 044 pumps waiting for me to construct the wiring harness from the relays and fuses that I got from Chris at Turbokraft. At Chris' suggestion I am going to run all new wiring on dual circuits/relays to eliminate any potential supply issues.

My AFR gauge has been in since the motor went in. I went with the WEGO IV on Al's suggestion and have been very pleased with it.