Sounds like an intermittent wiring issue. It's worth jiggling and moving the PCM and e-shaft plugs and the harness in between them while running your electrical tests above if you haven't already.
Don't know how much an E-shaft sensor is, but may be worth replacing that to rule it out.

Another less likely possibility is the PCM ground connection may be flaky, but I expect you'd see a number of other symptoms if that is the cause. May be worth cleaning up some of the chassis ground connections anyway.

Good luck.

Jimmy, Thanks for the suggestions. My thoughts exactly. I walked thru the above t-shooting the first time these issues surfaced. :sad: So, plan to take it to my local custom auto shop to t-shoot & resolve it. They do good work.

She's back. Picked her up from the shop Wed. :)

Good news: they found and resolved the electrical gremlin issue. :yesnod: I had a coil burn and fuse internally "closed". I have the coil. it's knarly, ...melted.
Bad news: she drove pretty bad after picking her up from the shop. Note: I only authorized them to repair the electrical issue.

So, I checked and tightened couplers I thought w/h been "touched" to do a coil job. Still ...driving issues: roaming idle, stumbling under accel., etc. :sad: After much t-shooting and discussion w/ Brett... he suggested I re-pressure test the entire intake (which honestly I'd been avoiding b/c my previous method req'd removal of the front bumper.) But it clearly was the right diagnostic step to take. Thanks for the nudge Brett! :icon_tup:

Thankfully, I was able to separate my CAI tube prior to entering the bumper and cap it there. So, no bumper removal. :cool: Then capped & pressurized from the throttle body. Pressure testing found that evidently the tech at the shop loosened E-VER-Y coupler clamp from the MAF straight on to the throttle body. :scratchhe Some were only finger tight. One section literally fell out it's coupler as I was setting up the pressure test. Smh. :uh:

But once I got the leaks sorted... she showed a brother love.:bluesuit:

She feels great: mannered, smooth idle & acceleration, seeing good initial HP & Trq numbers. Still need to dial in my EBC and work up rev range to WOT runs. More to come...

https://cimg6.ibsrv.net/gimg/www.rx8...5bc75f062b.jpg
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https://cimg7.ibsrv.net/gimg/www.rx8...094a0b8adc.jpg

EBC settings are still far from optimal...as I'm still seeing significant boost fall-off thru mid & upper rpms. That said I got a few runs in this AM before the rain yielding:

- @ 6.3 psi: 248 HP / 203 ft-lbs
- @ 7.2 psi: 284 HP / 216 ft-lbs

Great to hear it's all coming together well again ! How is startup now ?

The boost dropoff is solely due to the layout of the wastegate. You can play with 'gain' to get slight improvements but the only way to overcome it entirely is with an EBC that can do duty cycle by rpm.

https://cimg1.ibsrv.net/gimg/www.rx8...9feb5cb7b5.png

Start-up is good: Starts cold and hot w/ no throttle. :)

Edit: Yes, I believe the WG is well placed on the RX8Perf kit resulting in efficient WG performance. :icon_tup:. Better than desired in this case. :rofl: I'm still running a 4.5# WG spring though, and plan to swap in a 6#, or perhaps even 7.5# spring, which should reduce boost dropoff as well. :yesnod:

Also I found my tuning notes, trials & progressions, from last year which should help the process some. I'll eliminate as much dropoff as I can via WG spring and EBC tuning, but good to know that a progressive duty cycle EBC is required to eliminate it completely. :icon_tup:.

so enjoying this thread. thanks for the update.

please get some rain gutter material over that intercooler! :)

beers :beer:

Hey Swoope! Glad you're getting something outta the thread. :icon_tup: And yes, installing some mesh protection in front of the IC is definitely on the list. :)

Well, the rain stopped and I was able to get in a few pulls. :)

Below are the results of a 2nd gear WOT pull.

• Boost dropsoff from 9.5 to 7.2 psi can be seen in the first graph.
• The affect of the boost dropoff c/b seen in the declining torque slope after ~ 5800 rpm on the v-dyno.
• Taking the boost average... it works out to be a 8.3 psi pull producing 300 HP & 218 ft-lbs.

More tuning work to do... :yesnod:


https://cimg3.ibsrv.net/gimg/www.rx8...7132c7ca83.png
2nd gear WOT pull AEM profile showing boost drop from 9.5 to 7.2 psi.

TBD. Parameter were wrong. Need to regenerate this v-dyno.
2nd gear WOT pull M/E v-dyno

rx8 track reunion at barber motorsports park.. june 1,2

dont know how close you are. but big fun.

thanks for you posting.

beers :beer:

Thanks, Swoope. About a 4 hr cruise for me from Memphis area. I'll see if I can make it. Sounds fun.

This setup, w/ porting & ex-mani properly sealed, shows significant improvement in both curves, especially trq, across the rpm range as compared to my previous. :)

https://cimg6.ibsrv.net/gimg/www.rx8...af7a1034d3.png

Previous setup


Current setup
- TBD. My v-dyno parameters weren't correct, which m/h accounted for the curve differences here. Need to revisit.
- See post #380.

jcbrx8 be like

https://cimg9.ibsrv.net/gimg/www.rx8...1ff1f22c2d.jpg

:lol: :lol: :lol:

Congrats on getting back on the road and the performance in the target range, certainly has been a bit of a journey. Thanking you a lot for such a clear and well written thread, have just re-read it (again) and have a question going back to a post on Dec 30 (page 6 # 143) where you mentioned that the replacement emani gasket was thicker than the OEM one. Where did you purchase that emani gasket from?

[QUOTE=Brettus;4886896]Great to hear it's all coming together well again ! How is startup now ?

The boost dropoff is solely due to the layout of the wastegate. You can play with 'gain' to get slight improvements but the only way to overcome it entirely is with an EBC that can do duty cycle by rpm.


Brett; What EBC (brand/model) would you recommend for the duty cycle by RPM? Or other component/part changes for someone doing a new turbo install using the RX8perf kit.

Northzone,

Thanks, and glad you're finding the thread helpful. :icon_tup:

I purchased my manifold gasket here:
www.Gossettparts.Com
- PN: N3H1-13-461B
- $32.42, + tax & ship

Edit: After a bit more thought...I don't believe my new gasket was thicker than standard as it is the OEM PN. Conversely, I believe the old gasket was likely a reused / thinner gasket from when my reman engine was installed ~ 2011.

The only one I've had anything to do with is the one GregS uses which is a Greddy model (it works well from what I've seen). You could PM him to find out the model No.
With the rx8 perf kit you are kinda stuck with that issue , I can't think of any other way around it .

Update:

While working thru tuning I discovered additional “issues” from having put her in the shop. :sad: In addition to loose couplers…she recently went into limp mode. Didn’t take long to diagnose, thanks to our forum, that the likely suspect was the OMP pump. Sure enough found my OMP position sensor connector broken (see pic). AND after removing my turbo inlet section to better access the OMP, I discovered it’s compressor end significantly bent (see pic). :anger: Of course, I know it wasn’t previously like this b/c I installed it. Sigh…disappointing. I obviously intend to have a discussion w/ the shop owner, who I know, about these issues. :rant:

Bent the intake section back into proper shape. And attempted to repair and reinstall the OMP sensor (see pic), but …nada. New used sensor is on the way and s/b installed next week.

Pivoting to another front…cooling. Engine coolant temps typically run ~ low 190s F, but spike to ~210-215F after only 1-2 hard boosted accelerations. IATs run 10-15F above ambient temp (unless sitting in traffic. Then the fans kick-in). I’d originally planned to v-mount my IC which I believe is best case for both, but that would mean car back into a shop to fab it up. :nono: Change of plan: the objective is to get more air flow to the rad., which is currently blocked by the huge (28”x 12”x 3.5”) front mounted IC (see pic). So, instead I plan to purchase a 28”x 8”x 3.5” IC to free up 4” add’l space along the IC bottom which w/b ducted to the rad. I’m hoping to achieve coolant temps in ~low 180s (under similar ambient conditions as above), limit boosted run spikes to ~ 210F;…with IATs at 10-20F above ambient. :fingersx:

Need to get all this sorted out before getting back to logs…


https://cimg4.ibsrv.net/gimg/www.rx8...19904bd441.jpg
Broken OMP
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v


https://cimg5.ibsrv.net/gimg/www.rx8...1f7aa956e1.jpg
Attempted repair of OMP. Nada...didn't work.
v
v

https://cimg2.ibsrv.net/gimg/www.rx8...231b771bc1.jpg
Another shop incident: bent intake section
v
v
https://cimg3.ibsrv.net/gimg/www.rx8...7b9c0a61d5.png
Current FMIC (blocking rad). Red line indicates approx. bottom of new IC...allowing ducting of airflow to rad.

See if you can get a 10" and mount it higher . Would be a good idea to get a better quality one too seeing as you will be reducing it's size .

TR1035 Intercooler 666HP - TREADSTONE PERFORMANCE

http://www.treadstoneperformance.com...rcooler++500HP

You were right. :icon_tup:

Yep, I'm looking at the Treadstone 500HP you list above... and the below FSWERKs model:

https://www.fswerks.com/products/fsw...s-st-2013-2018

My current IC is 12" tall and mounted as high as possible. 3" is blocked by crashbar and 9" open to direct air. An 8" mounted as high as possible places 5" in direct air and frees up 4" of rad flow. Additionally, I'll have the option to slide it downward to the bottom of the crash bar placing the full 8" in direct air, and adding only 1" more rad flow. So, I believe it will provide the greatest flexibility. :yesnod:

Looking closely, the oil cooler fins seem pretty beat up and bent over, straightening them will help a bit with the cooling.

:rofl:. :rofl:. :rofl:. :rofl:.