HPFP cant keep up I think :(

[shushikiary]

So I've been chasing a few things around and I got a lot of my tuning issues figured out with making sure actual load doesnt exceed requested load, etc.

Sadly though, I think I found the limit of my HPFP with 100% E85. In the log below everything is fine except once the boost gets high up there the HPFP drops down to 500 psi . Once it gets that low the ECU seems to pull timing across the board even though everything is great (AFR is fine, STFT's look fine, everything looks great).

What's sad is that at higher RPM the pump can keep up just fine! Its in the 2k-3k RPM range that it appears it just cant keep up... which makes me a sad panda. But then again, this is at 20psi in very cold weather (yay 43 deg F IAT's!)

Am I right in thinking the reason the HPFP cant keep up at lower RPM is because its chain driven from the crank and thus at that RPM it just cant move enough fuel? If so I guess it might be time for port injection, throttle body injection, or a shotgun fuel pump .

http://datazap.me/u/shushikiary/requ...olo=19&mark=24

[Flinchy]

out of curiosity, how much power are you making off it?

[shushikiary]

I've never put her on a dyno, so I have only ball park idea's based on other people running similar setups. Other people running nearly the same mods/tunes as me put down around 400-450 whp and 450-500 wheel torque, but again thats really speculation.

[Icewall]

if it was me I would go back down to say e50 or e40 blend. If you do go PI make sure both lpfp and hpfp are happy. if not then the ethanol content is too high. that just my opinion on the matter.

If you go port injection it will make the problem worse because now the lpfp wont be able to deal with feeding PI and DI at the same time and once the lpfp loses pressure the next thing to have less pressure is the hpfp.

[Sticky]

Dial down the ethanol as recommended and see what happens.

[shushikiary]

Yea I just dont want to have to go back to an ethanol blend. I've been spoiled with E85.

As a stop gap solution I reduced the boost limit multiplier at that MAF g/s.... good enough for the moment at least.

I already have the stage 1 FUEL it, which given the flow rates suggests I could support 100HP more on that even with TBI, but if I bite the bullet and go PI then I'd switch to a stage 2 from fuel it as well, solving the LPFP problem for these power levels.

As a stop gap the TBI from fuel it is very temping, but if I ever go say stage 2+ or the like and shoot for 700 whp, TBI wont be enough... so its a tough choice. Do I spend 2k and go for PI with a stage 2 LPFP and be set for some day with larger turbos, or do I spend 700 now and be good enough but then have to most likely add PI later if I go larger turbos.

Ah how the present choices affect the future in such complicated ways.

[shushikiary]

Yay port injection... it works:

http://datazap.me/u/shushikiary/de99...-20-21&solo=20