Hesitation in boost and high rpm

polskifacet · January 19, 2017, 12:01:03 PM

Looking at derfdog's log, his frp drops to 9 MPa and recovers but the tune is also running 12.5 afr vs w.e LMS is wanting which looks to be 11.

AJP turbo · January 19, 2017, 12:07:37 PM

Quote from: polskifacet on January 19, 2017, 12:01:03 PM
Looking at derfdog's log, his frp drops to 9 MPa and recovers but the tune is also running 12.5 afr vs w.e LMS is wanting which looks to be 11.

Derf is running E20 so its not comparable entirely....he is NOT running 12.5 afr...his stoic is lower so his afr is actually about 11.4

Thats why is kinda better to read lambda and not afr

AJP turbo · January 19, 2017, 12:13:48 PM

And derf is running more boost....so couple that with E20 and its a double wammy on the fuel system...its heavily taxxed so not a good comparison for your tune but it shows you how your fuel system suffers with alot less demand than derf

The log i sent you was much closer to your tune.....it showed the same desired boost...however i only had the guy run a 2 bar map sensor and you saw his fuel pressure was completely flat

AJP turbo · January 19, 2017, 12:42:56 PM

And although you can maintain afr even when fuel pressure falls its not ideal...so when fuel pressure falls that doesn't mean you will go lean...it means the pulsewidth of the injector needs to increase to deliver the same fuel mass if pressure is down

MiWiAu · January 19, 2017, 01:08:07 PM

Not sure if it helps or not, but here is a log of my XSport in cold(er) temps. I'm not certain, but I assume the fuel system is the same as the SHO?

I also had the AJP boost regulator installed, so it would have helped minimize pressure drops during shifts.

Ambient: 8.6 F
IAT2: mid 50s at start of runs
Target Boost: 14.5 PSI

Note, since this log was taken, I've changed the regulator boost reference and moved down to 15.95 PSI springs, which helps with the pressure drops. We've not had any bitter cold since making these changes, but if it gets back down close to 0, I will log again for comparison.

derfdog15 · January 19, 2017, 01:13:59 PM

Thanks to AJPTurbo for chiming in, I should have mentioned boost levels/E20 on this post as well, though I believe they are mentioned on the respective posts with the logs.

If you look at lambese it hits the .85 target at WOT consistently on the latest revision, not sure what the target was on previous revisions, though I believe it was the same. As AJPTurbo mentioned, since I am running E20 my stoich point is a bit lower, E85 stoich is 9.8:1 vs. 14.7:1 for regular gas. My stoich point is somewhere in the 13.5-13.7 range IIRC.

AJP turbo · January 19, 2017, 01:37:08 PM

Quote from: MiWiAu on January 19, 2017, 01:08:07 PM
Not sure if it helps or not, but here is a log of my XSport in cold(er) temps. I'm not certain, but I assume the fuel system is the same as the SHO?

I also had the AJP boost regulator installed, so it would have helped minimize pressure drops during shifts.

Ambient: 8.6 F
IAT2: mid 50s at start of runs
Target Boost: 14.5 PSI

Note, since this log was taken, I've changed the regulator boost reference and moved down to 15.95 PSI springs, which helps with the pressure drops. We've not had any bitter cold since making these changes, but if it gets back down close to 0, I will log again for comparison.

This log might not be best either...you show a substantial fuel pressure drop because the throttle is open which allows the boost to spike and the spring in the gate mod was too high but i think at least you see fuel pressure recover at a higher boost level than polski

MiWiAu · January 19, 2017, 01:59:45 PM

Quote from: AJP turbo on January 19, 2017, 01:37:08 PM
Quote from: MiWiAu on January 19, 2017, 01:08:07 PM
Not sure if it helps or not, but here is a log of my XSport in cold(er) temps. I'm not certain, but I assume the fuel system is the same as the SHO?

I also had the AJP boost regulator installed, so it would have helped minimize pressure drops during shifts.

Ambient: 8.6 F
IAT2: mid 50s at start of runs
Target Boost: 14.5 PSI

Note, since this log was taken, I've changed the regulator boost reference and moved down to 15.95 PSI springs, which helps with the pressure drops. We've not had any bitter cold since making these changes, but if it gets back down close to 0, I will log again for comparison.

This log might not be best either...you show a substantial fuel pressure drop because the throttle is open which allows the boost to spike and the spring in the gate mod was too high but i think at least you see fuel pressure recover at a higher boost level than polski

Good point. I think the last part of your statement there though may help reinforce something on his end is askew, which, in retrospect, probably isn't all that helpful, since I think that's already been the conclusion.

I just like to participate.

polskifacet · January 19, 2017, 02:07:05 PM

Low atomization is bad in DI since it uses evaporation to help cool the cylinders. But anyway hopefully I will have facts for you guys tonight. I'll put this out there now since its probably an inevitable test, for the fuel volume test at the schrader valve, how much fuel should I get for X interval?

SHOdded · January 19, 2017, 02:25:03 PM

Good luck, polski!

polskifacet · January 19, 2017, 10:20:24 PM

Lines are all perfect, no distortion of any sort. I wasn't able to get the pump out, will try to source the tool tomorrow, worst case I have to buy it for $50 online.

StealBlueSho · January 19, 2017, 10:33:14 PM

Quote from: polskifacet on January 19, 2017, 10:20:24 PM
Lines are all perfect, no distortion of any sort. I wasn't able to get the pump out, will try to source the tool tomorrow, worst case I have to buy it for $50 online.

I used a rubber mallet and a chisel, slowly working my way around the ring until it popped loose...hind sight 20/20 I should have just rented the damn lock ring tool... cause putting it back on was a nightmare...

Advanced Auto parts has the tool for free to rent if you put a deposit on the kit... at least the one by my house..

Sent from my iPhone using Tapatalk

polskifacet · January 20, 2017, 11:36:23 AM

I had to buy the damn tool, apparently no one has it in Chicago lol. Scheduled delivery tonight so hopefully I can capture that log too.

StealBlueSho · January 20, 2017, 11:39:28 AM

Quote from: polskifacet on January 20, 2017, 11:36:23 AM
I had to buy the damn tool, apparently no one has it in Chicago lol. Scheduled delivery tonight so hopefully I can capture that log too.

Yea, there a ton of videos of how to make the tool with various common place tools just for that reason.

Sent from my iPhone using Tapatalk

polskifacet · January 20, 2017, 11:33:22 PM

Changed the pump, it was a SOB even with the tool. Logs look better but I attribute that completely to the fact its 20f warmer today then previous log. Still drops down to 1000 psi with kick down from 5th to 2nd. Logs 6 and 7 are with the new lpfp. Now the ball is in LMS's court since it must be a tune problem which seems to heavily be linked to ambient temp. Lmk what you guys think.

Note: no Hesitation on these runs

http://polskifacet.dynu.com:55698/uploader/uploads/Pictures/Logs/