Originally Posted by devtec
Hi all,
Longtime lurker here, and early adopter of the Edelbrock s/c, installed November of 2015 with 9k miles on the car. Have had a long road, but finally here, I think. A bit of the story of the car:
- Driving home from official approved Edelbrock installer, the s/c seized. Car towed back and Edelbrock sent out new s/c unit. Reinstalled.
- But from the beginning, car suffered from significant jerking/hesitation/stumbling problems at partial throttle starting from a stop. Puzzling as it seemed no others were having these problems. In reading through all 190 or so posts on this thread over the years, though, it seems that slowly others started reporting similar behavior (86fun, lunatic, sargy, clayrush, B_T, BigFatLip, Luftwaffel, shiumai, etc.).
- Relatively soon after the install, I switched to the Delicious tune hoping it would improve things. It was world's better than the early Edelbrock tune, but it did not solve the hesitation problems.
- In trying to troubleshoot, went through all of the following:
Smoke tested, and all possible vacuum leaks addressed
- MAF O-ring found to have leak and replaced with O-ring from CSG (check this!! improved, but did not completely stop hesitation)
- Edelbrock bypass actuator found to have leak and replaced with new part from Edelbrock (check this!! improved, but did not completely stop hesitation)
- intake manifold gaskets replaced at the time bypass actuator was swapped (did not improve hesitation)
Hardware
- added Delicious D box (did not improve hesitation)
- installed revised Edelbrock MAF air flow straightener intake housing (did not improve hesitation)
- MAF sensor cleaned with MAF sensor cleaner repeatedly (did not improve hesitation)
- MAP sensor replaced with new Bosch part (did not improve hesitation)
- throttle body replaced in case it was the TPS sensor (did not improve hesitation)
- added grounding kit and did Big 3 since I have an 1100W sound system (actually did help significantly with hesitation)
Throughout all these, the hesitation on light throttle never went away, but seemed to lessen very slowly over time. In addition to addressing the legitimate problems (O-ring, bypass valve), I think it was constant refinements by Zach from Delicious with flash tunes done by remote logging. With these, the jerk had been reduced to a slight stumble (especially with the V22.0 Delicious tune). By this point, I had 42k miles on the car!
Finally having gone through all of the above, and with stars aligning for me at work to get the free time, had the car dyno tuned at Mann Engineering in Santa Clara, CA a few days ago.
Results are attached.
2015 BRZ Limited, 42.5k miles
Edelbrock s/c
Ace Type 350 header
Milltek Secondary Catback (Resonated)
This tune was WITHOUT a D-box, since my early unit was malfunctioning. Delicious will be replacing it, so hopefully may get another 10 peak horsepower or so once it's in.
No more hesitation. Car is smooth, quiet, and powerful. On my stock BRZ with my mixed driving commute, I was getting 28.5mpg. With this tune I am getting about 30mpg.
I just want to thank Gary at Mann for amazing service and an incredible facility (with a Maha dynamometer). Likewise thanks to Bill and Zach from Delicious. I could not recommend these guys more strongly, for sticking with me through countless emails and ten remote tunes, and delivering in the end with an in-person dyno tune that solved all the problems. All in all, was it just a tuning issue? Not sure, as there were some hardware issues, and it is still unsolved as to why some cars do not respond well to tunes that work great on other cars.
At this point, don't much care, as I am finally truly enjoying my BRZ.
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