got this samething when i cranked boost. it was in early rpm range when doing logs from 2000 rpm. stock turbo and pump. everything else on the car was stock except for a 3" TBE.

looked the same as the logs posted by the OP

 

Well, today, I was able to completely eliminate this by adjusting by Synapse DV and lowering the gain on my EBC (Greddy Type S). I think the EBC setting is what cured it...I will test some more this weekend, time permitting and post up some results.

I did a few pulls, though, and the surge seemed to be completely gone...nice and smooth all the way up to 29 psi or so. I wasn't logging, though, so I will do that and see if it's gone. I'm doing a lot to my car with my new CarPC install, so time is tight, but once that is done, I will get to fully tuning my E85 maps and then maybe even switch to SD again and test things out with my new injectors, E85, maybe install my 4" intake/filter.

Glad to see others are/were having the same issue though.


Eric

 

OK, surging is fixed with EBC gain adjustment. I finally got to start tuning my E85 tune. Here are the results from the first pull, no tuning yet (timing ramp was 2* at peak torque to 13* at 7000RPM).

This is a comparison of a few months back on 93. No other mods other than E85. Both of these runs are through the stock cat-back. Opening the cut-out on 93 netted me another 30whp, IIRC.

Boost: 30psi to 22.5
Timing: 2* to 13* (initial run, still tuning)
AFR: 12.4 to 11.3 (initial run, still tuning)

Dynojet correction factor of 1.11 (uncorrected):


I don't think I will ever switch back to pump gas now. I guess we'll see how long I can last until the Chicago winter comes. I will do my best to try to tune the injectors to start all year. If not, I will switch back for the coldest months. So far though, E85 is great...anyone that has it around them should definitely switch.

I did one more run with +2 degrees timing from 5500RPM+ and the log shows some more gains, but I got 1 count of knock right at peak torque, which messed up the curve. So, tuning to come, but I'm probably going to stay pretty conservative with the timing.


Eric

 

your running not nearly enough timing for e85 if your going from 2* to 13*. crank it up, i typically aim for 20* at redline if your boost is tapering to 22.5psi. obviously every setup is different but i always start with the timing 3-4 degrees advanced from 93 across the entire range.

 

Yep, as mentioned, that was my initial pull...not my final tune. Just happy about the results with minimal tuning.

One thing I did forget, though. I changed to 255/40/17 from stock (upgraded to Volk CE28N), so the numbers are 9 tq/hp lower.


Eric

 

Nice gains... Nice and smooth too! what smoothing facotor? looks like fun!!! wish we had some E-85 out here in socal...

 

The smoothing factor was 3. But, the smoothing factor is dictated by the speed of logging.

MY original DMA logs logged so fast that I needed a high smoothing factor, like 9 or something. These last logs were pretty slow (probably because I have been adding my crap code to John's LiveMap program) so only minimal smoothing was needed.

 

After switching to an exposed element filter a few days ago, I can hear the turbo much better, and when the motor is spooling starting from 2200 rpm for a 3rd gear log, I can hear the turbo stuttering a bit. Its not enough to show up in the logs, but I can feel it. I figure its either surging, or its the 20 Hz duty cycle of the BCS causing the WG to oscillate.

 

I get this stuttering as well.
I just noticed Im surging a bit in 5th...

 

I will get a log, but I believe I am seeing the same thing in hard roll-on's in 4th gear. I get really bad stuttering between 2200 & 3200 rpm's..

 

I have also experienced what I would asume is some kind of break-up/surge with my car on e85, tt happened as the turbo was spooling up to peak boost ~3500-4000, under high load and typically happened more often in 4th gear and higher. However, when I turned my boost up past 28psi it went away, dont know why. Maybe if you turn up the boost and it goes away, you can figure out more about what is going on.