My 2.0 ABF Dyno run. Power seems down and AFR is high.

Yep, unfortunately, those figures (amount of fuel delivered in 30 secs, or something) is based on cracking off the fuel pipe and collecting it, in other words at no or insignificant pressure. So in retrospect, the injector test could be useful to correlate fuel supply (volumetric flowrate) at pressure, against the above test of volumetric flowrate at no pressure.

I never did this because I immediately saw AFR changes with adjustment of control pressure all thru the rev range. In other words, I was happy with fuel flow because during the tuning, it went into the rich misfire limit area. I guess once you've gotten the wideband and done some runs, if you don't see AFR changes with control pressure as appropriate, it could be a reasonable test.

PS I'm using a Merc 6 cylinder K-Jet pump, but I'm led to believe the stock fuel pump is pretty good anyway and should flow fine to around 250-300bhp. Brookster, I know you're running nitrous too, did you upgrade the pump or use the stock component?

 

Actually, I`m happy to stick with K-Jet, it has served me well for the last 2 years and a LOT of track abuse, its just not quite as easy to fault find as i`d like

 

Paul, this is an out and out track car and doesn`t do `traffic`

 

Yes but I imagine you'll want it to start and drive from cold, warm up okay without constant 'babysitting' and be able to sit in a queue of traffic and move up the queue, and be driven gently around sighting laps and red flag situations, etc. No point in making it undriveable for the sake of it.

 

Agreed about the idling !

Thats great info for checking the fuel flows, I`ll definately be able to do that. THANK YOU.

 

I have 4 calibrated containers, a piece of ally bar and a bridge for the fuel pump relay.

1) Pop the injectors and make sure they are comfortable in the 4 containers (i.e. wont slip out half way through!)
2) Bridge the relay (i.e. turn the pump('s) on
3) Get my stop-watch ready and place the piece of ally bar under the metering flap (i.e. force it open a repeatable amount)
4) Watch the injection patterns
5) Run it for x seconds and remove the ally bar
6) Check the contents of the containers (i.e. all equal?)

I do this when I assemble a "new" fuel system, then down the line if I suspect trouble it's very easy to repeat the test and see if there is a change.

It's not 100% reliable (of course opening the flap static does not replicate WOT running) but it's a help.

I put this (info above) in the other thread (with the piston pictures) but have deleted this info because it's a dangerous test. Your messing with atomised fuel, it's easy for something to go wrong, do it in a well ventilated place, preferably outside, with a "calm" helper and an extinguisher...

K-Jet pumps (when within tolerance) are easily capable of fueling well in excess of 300bhp when fitted to a "conventional" injection system, there is very little difference in the volume and pressure of a K-Jet pump and the lower end Bosch "motorsport" pumps. You'd be surprised how many group N rally cars are running round with what are essentially stock VW/Merc K-Jet pumps in them.

The (K-Jet) pumps are "good" because K-Jetronic requires a pump that produce quite high pressures

Cheers

Simon

 

I'm running Standard Bosch fuel pump (Brand New) it will run an extra 150bhp of Nitrous without a problem. I have a fuel pressure gauge connected to keep a constant check too.

Back in the day, a few of the 8V Boys i used to run about with used to unbolt the WUR from the block for racing.

 

I'm still using the mk2 16v main pump on my VR6, can't see any point changing it.

 

Thinking back to the original posts in this thread, I remember that you said the RR operator checked the control pressure on the fuel system, but did he also check the pump pressure? It should be about 5 bar I think.

 

I use a 16v Kjet pump and even the lift pump on My WOLF R turbo. No issues with delivering the fuel to the 285ps thirsty cylinders.

 

Mine is running 80psi

from memory of think VW Sate 75psi from factory.

 

The wur pressure is about 5 bar system pressure and 3.3bar control pressure (from memory). They are checked and as per the WUR mod thread.

 

So if you have replaced these parts, as you say, all you have left is the two pumps, filters and the rest of the supply system.

Checking voltage is done under load not at idle.

Have you checked your lift pump filter (and the bottom of the tank with a torch to check for gunge)?

When the RR test was done, was it the control or the system pressure that was monitored under load?

Cheers

Simon

 

Not necessarily, because the (correct and working fine) components might not be set up correctly. Hence the above discussions.....

 

when my lift pump was failing the car violently kangaroo'd under accelaration.

good luck with it nige.

 

Surely the whole point of using "known good" parts is to enable some assumptions to be made?

OK we can't say with 100% certainty that the parts fitted are working and / or set-up correctly but is does "point the finger" at the pump('s) and / or filter('s), and lets face it, they are not exactly hard to test / check!

Simon

 

Its still a bit indirect, I'd prefer to directly measure the key parameters and adjust what you can, only after measuring.

 

Of course and personally I would take this approach too!

But in this case the chap has chosen shall we say a more "add hoc" approach, hence the assumption that the parts he has obtained are "known good".

As you say, in reality we don't actually "know" they are good, we are just assuming so and as assumptions are generally the mother of all f**k up's it does not bode well! LOL...

Ah it's late, I'm just messin

Cheers

Simon