Project XXX AWD WHP Or Bust!

[Alpha D]

It smelled quite rich, no clouds of unburned fuel or anything crazy like that though. Im not sure and wonder if maybe my small 560 cc injectors braced the volume slightly. Since i wanted to keep those in untill everything had been buttoned up then switch over to e85 with link installed Can we honestly say that the fuel could of caused this. . .because just before the last start up i put fresh oil in it again. . .

Another question: I have or had ...a key diver chip that was programmed for 1G piston refering to the stock 1g compression ration, my 560cc injectors ect. . . the engine however has/had 2G pistons. . .could the 7:1 or 7.8:1 1G compression ratio? Compared to the 8.something 2G piston compression ratio been a cause for such destruction? Doing some resarch tonight i came across that the timing maps for the 1G pistons are way more aggressive then the 2G pistons making tuning ect harder with a 2G piston set up and less room for error while tuning? This is a WHOLE NEW BALL GAME TO ME NOW. . .

Seems like all these small things could of added to the results i came up with. . .

[goodhart]

1g pistons = 7.8:1
2g pistons = 8.5:1

[s1ngletracker]

Whoa you were running dual pumps on the stock FPR? A single 255 is borderline over running the stock FPR at idle. I can't imagine how much you were over running it with a dual pump setup.

precisely. My single 255 overran my stock FPR...

However, unlikely that detonation caused your problem.

[Shane@DBPerformance]

You need a good FPR to run 2 pumps all the time, even some aftermarket ones don't handle 2 pumps at low load perfectly. A lot of people with 2 pump systems have the second one come on at 15 psi or whatever instead of running them all the time.

1G ignition timing with 2G or higher compression is not good. It depends on what was actually in the chip though and what kind of boost the tune was meant for. At 20psi with 8.5:1 compression you might only be able to get away with 11-14 degrees of timing on our normal pump gas, while the stock 1G timing maps would be trying to run 22-24 degrees. It probably would have been lower in a chip that had the timing maps modified though, because the stock 1G ignition timing doesn't work very well even on a stock motor 1G unless you are running low boost or race gas.

[Alpha D]

1g pistons = 7.8:1
2g pistons = 8.5:1

Thank you goodhart ha i was almost close!

Now talking about the stock FPR im not sure if i excactly understand or if i have the right concept in mind. The purpose of the fpr is to keep a constant pressure of fuel. . . the less fuel you move through a specific diameter of pipe in our case fuel lines the less pressure. . .the more fuel (dual 255) the more pressure. In the case of a dual 255 set up to much fuel for the stock fpr to handle? Now where does the problem come in the excess fuel not being bled back in to the tank. . .How excactly does this result in overfueling?

I thought the injectors are only open for a certain amount of time or duration, now is the over fueling caused by the high amount of pressure squeezing more then the normal amount of fuel into the cylinders each time the inectors fire. . .or do they leak how excactly does this work? Im just curious. . .seems to be a simple concept yet i overlooked it and could, more like did contribute to the problem for all i know.

Moving on to the compression ratio @ shane the timing info would that only apply when putting the engine underload/boost not during idle? & Could one so to say pull on boost given the psi stated cause engine failure? Because if yes then perhaps that could of been the reason as well. What i would like to know is whether this dilema was caused due to a mechanical failure (loose bolt, interference ect) which im really leaning towards or Electronically (timing, fuel pump, the other not so obvious possibilitys)

[s1ngletracker]

It's really hard to say what caused the failure. I can't really even see whats going on in your pictures. Get it taken apart and take more pictures.

To answer your fueling question, yes, the increase in rail pressure is due to the orifice in the stock FPR being too small to bleed off the excess fuel flow from the dual pumps and causing pressure to build. This makes your car run too rich. What Shane was talking about regarding low load, at idle or otherwise low engine load is when the most fuel is being bled out the FPR and returned back to the tank as your engine requires little to run. The pumps are operating at full output all the time, regardless of your engine RPM or load.

[blackawdtsi]

I thought the injectors are only open for a certain amount of time or duration, now is the over fueling caused by the high amount of pressure squeezing more then the normal amount of fuel into the cylinders each time the inectors fire. . .


This. There's a possibility that if there was enough fuel, it would get past the rings and get into your oil. However you would've heard spinning bearings followed by a loud deep knocking.

[Halon]

Fuel rail pressure will go up when you overrun the stock FPR, most noticeable at idle/low load. At a higher fuel pressure, the injector will flow more fuel, hence the richer idle. I'm not saying that caused your problem, I'm just surprised you were running dual pumps on the stock FPR.

[Alpha D]

Well thank you guys for the input. Never hurts to ask for clearification :)

[bertrenolds5]

This. There's a possibility that if there was enough fuel, it would get past the rings and get into your oil. However you would've heard spinning bearings followed by a loud deep knocking.

He probably heard something like that as the engine block exploded. I have to say, holy crap you were running dual pumps on 560cc injectors on E85? I thought you werent supposed to go below 720's and even thats pushing it, and no fpr? You need the AFPR because your telling dsmlink that you have a base fuel pressure of 37psi so if it's not 37 then your going to have problems. Once again, holy shit you were running a stock fuel pressure regulator.