So I made the switch to e85 on my ALT maps for 94170715. I use the IC button to activate the tables. Everything seems to be working very well. Fuel trims are within 2%, idle is rock solid, open loop cruise working like a champ to my desired values in the ALT tables. Running 30psi peak that holds 27 to redline. Running 1450cc blue max injectors, walbro 255 (unmodded), and the rest of my mods in my sig.

Problem 1

I cannot get the car to run any richer at WOT than 12.4 (bad I know). I have tried lowering the AFR values well into the 9s to no avail.

Problem 2

Any boosting under 3500rpm results in what feels like a missfire. No knock at all. Timing is not aggressive at all. I have the HKS DLI II, RalliArt wires, and 8 iridium plugs.

I tried adding fuel and removing timing....to no avail.

The car won't do this if I am at less than 90% throttle. The car does not have spark blow out at any other rpm. WOT is fine if I am above 3500 rpm. Lean spool is disabled via periphery bit.

Any ideas to resolve this would be wonderful.

TIA.

Paul

 

What are your IDC's? Has to be a shortage or limitation of either fuel flow or fuel supply, me thinks.

Any chance this is compressor flutter?

Have you been able to data log this anomaly?

Have you tried copper plugs gapped down to, say, 0.018"?

 

On a WOT pull my duty has not been over 56% with a 33psi spike holding 27 to redline.

I have not tried copper plugs. If this were the issues I would have problems at high rpm with spark blow out....of which I don't.

I don't believe it is compressor flutter, but could possibly be the turbo being on the verge of the surge line. It builds boost extremely fast.

On a 4th gear pull I started at 0 boost at 3500, by 3900 I was at 30psi. It is nuts.

I did a pull at 1500 in 3rd gear by 1625 it as 0.6psi, by 2500 it has 4.9psi, by 3000 it has 11psi, by 3500 it has 22psi and by 4000 it has 32.7 psi.

 

I did notice that when the car has problem 2 that load drops as well for an instance. Then it goes back up as the car continues to accelerate. This happens every time I go WOT under 3500 rpm.

 

what happens when you log AFRMAP?

what about richening up the normal map( if you think altmaps isn't working )

 

I have not logged AFRMAP, just 1 byte and 2 byte. Funny thing is that 1byte won't dip at the problem area below 3500 but the 2 byte does.

I will log AFRMAP next time I pull.

I will swap my e85 tune to the normal maps.

FWIW...I am using the ICS as my source to switch between them. I confirmed it does work with the injector scaling (fuel trims adjusted correctly for lower e85 scaling) and the ICS light does flash when in the alt map mode.

 

Could be dieing fuel pump as far as the fueling goes, sounds exactly like the symptom of one.

What heat range plugs?

 

If it was the fuel pump, wouldn't I have issues at the top end WOT when my injector duty cycles are much higher? I may pull it and mod it (press in the relief ball) to see if it makes an improvement. FWIW I do have an AMS fuel rail too.

Plugs are NGK BPR 8 EIX. Iridium. They have less than 1k miles on them.

 

Compressor surge actually sounds like the most obvious choice here because of how fast it builds boost. What BOV is on the car? If it's not stock and you can put a stock EVO9 valve back in it, try it and see if it helps.

The injectors are big enough to overcome the pump shortage, as you said the duty cycles are under 60%, I'd guess it's not a pump issue.

You know you are welcome to come up anytime and use the dyno, I can help you try and sort through it if you like!

 

BOV is an APS dual port.

A trip to Wakeman just isn't in my future, unfortunately. I know you would be impressed with the #s for an old school 20g 9 LT aka Green.

 

Anyone else have any ideas ? ? ?

 

Will the AFRs come into line if you run at lower boost, say 22 psi?

 

It does appear that lower boost levels will allow for closer to AFR values I want.

 

I am looking for a good VE calculator.

I think Buschur may be on to something about the turbo surging at under 3500 rpm. I have my compressor map so I can calculate the boost pressure it can do at a given VE and RPM.

 

Perhaps the relief valve on the fuel pump is going bad. Any easy test would be to swap out the fuel pump.