Power choke at high rpms at full throttle, but lifting off a lil gives more power

[drunkentrader]

Sorry, not a super technical “turbo” guy, so hard to explain in the right terms.

When doing hard pulls in higher gears at high rpms, I can feel the car being choked, and when letting up the gas from WOT to 80% results in the engine making more power. I do not run linear throttle mapping.

Running motive flex fuel kit, PFS POD, VTT GC lites 2.0. Inlets, outlets, 5” intercooler and downpipes. E50 fuel. Plugs are new, as are the index 12 injectors

I haven’t logged this happening, but can if what I’m experiencing isn’t a well documented tuning or hardware issue.

here is a recent log I just sent to my tuner. This is the first log since installing the motiv flex fuel and hpfp overdrive.

datazap.me | drunkentrader | 3rd and 4th WOT

datazap.me

^noticed my IATs running to 140… going to install a 7” intercooler. And the ugly timing corrections — which are part of the issue I am experiencing?

 

[carabuser]

Log looks rough, I was going to suggest you find a tuner but it seems you already have one. If he can't sort it out then find someone else.

A larger intercooler would be a no-brainer though.

 

[NoGuru]

Too much boost for your Intercooler to handle. Once you install the 7" it should clean up those logs.

 

[drunkentrader]

got the tune updated.. still having the same issue with hitting a wall at times in 3rd gear and higher at over 4k rpms... but as soon as I let off the throttle boost increases and it feels like its running well.

I may have to actually simulate what I am talking about and log it. the log below is just a standard 3rd gear WOT pull, and a bit of 4th WOT.

datazap.me | drunkentrader | 3rd and 4th WOT

datazap.me

 

[carabuser]

Still a really ugly log. Do people really charge money to do shit tunes like that with a 2 week turnaround?

It would be useful for you to log the actual final wastegate position. Can't tell if you have a boost leak or the tune is just applying a really low final wastegate position. You have serious post shift timing corrections and the rail pressure is bouncing around a lot.

The rail pressure should be as smooth as possible. The PFS POD will be the cause of that, do PFS offer any suggested tuning changes when using their kit?

 

[carabuser]

Also it looks like the tune is a scaled boost map as the reported load is completely wrong.

I understand the need for scaling over 22PSI but your tune should be fine without. If you did want to go higher than you'd only need a small scale.

 

[drunkentrader]

^^Thanks. Unfortunately I’m just too ignorant to be able to read logs and fully understand which parameters stand out as red flags, etc. the two logs are the first flex fuel tune and first revision. Under normal driving circumstances, it drives flawless. It just feels like it hits a wall in the upper midrange in 3rd gear and above… and when I feel that wall and let off the gas a bit the engine and turbo open up/make more boost and it accelerates cleanly. Not totally sure if it’s all tune or a hardware issue, or a simple leak. Had the same issue prior to adding the flex fuel bits and tune.

just wish this problem had some sort of simple and logical explanation. I also noticed on the two logs the car felt a little rough. I usually do my logs at night when no cars are on the road, and that usually means temps in the low 60s vs mid 70s/80s during the day. Literally the only difference, and you would think it would be running crisper in the denser air, but the last to times I went to run logs the car just felt like it never “warmed” up and was just grumpy... and the exhaust audibly had noticeable drone.. My guess was waste gate actuation making the drone? My car just has downpipes and a 335is muffler and never drones and always sounds civilized when not at WOT.

maybe I’ll take the car in for a boost leak test. Also considered swapping out the turbo smart dual diverters for a blow off valve.. though, not a big fan of bov noises. Not super tech savvy with turbo systems, but was thinking a single bov is much simpler in plumbing than the dual diverters. Very frustrating experience with my car. Most everything is new in the last 20k miles(81k miles on the car now) and never gets abused, but at the same time I don’t think I’ve ever been satisfied with the way it drove. Stock turbos on a OTS e40 tune gave more consistent grins than I’ve ever had with the upgraded turbos and fueling system.