I thought the same... and swapped the rubbers way back during my initial install - see below. I ultimately swapped them back for some reason I can't recall now...

And installing the large washer between the lower rubber & bracket arm... well that just makes entirely too much sense for me to have thought of. What... and to have missed its opportunity to be a completely useless ornament. :yelrotflm. Smh. :uh:

Working the passenger-side mount... around the compressor, inlet section & coupler, mounting bracket, limited space, etc....is NOT fun. But yeah, I'll get these sorted next opportunity. Thanks :icon_tup:

https://cimg2.ibsrv.net/gimg/www.rx8...47910e1aec.jpg
Passenger mount w/ swapped rubbers...

That explains the engine height issue . Def. put the larger washer on top of the lower rubber next time you mess with it .

So, after decatting and more EBC tuning...I started experiencing this same issue as back in Feb: stumbling, hesitation, misfires on cylinder 2 under high load. After no luck checking injectors, and coils...I cleaned & swapped back in the 4x R6725 105s, and so far so good... no misfires under similar load conditions. Why these worked now, but were allowing misfires before? Perhaps just fouled... :dunno:.

Here are the BUR9EQs after pulling them out.

https://cimg2.ibsrv.net/gimg/www.rx8...179f9bc671.jpg

Thought you had a dodgy coil originally?

True, the coil was the ultimate culprit of the electrical gremlins issue. And you're right it was probably presenting issues before then too...causing or contributing to the misfires. :icon_tup:

Update:

Even after swapping coils I continued to get misfires particularly under load in 3rd & 4th gears. Also had a pesky boost leak... contributing to rich AFRs, likely contributing to misfires. So, idle and performance was a bit unstable at low speed, low rpm; better thru midrange, and misfiring in 3rd & 4th gears upper rpms under load. Problem was couldn't really address the issue w/ tuning until I resolved the leak, and after
- pressure testing CAI to TB - nothing found
- removing & inspecting the UIM - nothing found
- removing & inspecting the Oil filler neck/vacuum chamber -nothing found

I couldn't find the leak. :wallbash:

Then I discovered a different method to check for leaks: smoke testing. :smoker:. Using a cigar as the smoke source, and a hose to the UIM brake booster nipple; I blew smoke into the UIM. Literally found the leak in two minutes! Leak was at the last charge section coupler to the TB. Few turns on the clamp nut..., and an update to my tune (thanks Brett) and I'm seeing progress. :yesnod:


https://cimg3.ibsrv.net/gimg/www.rx8...bced63409.jpeg


Good news: noticeable improvement in idle, low speed low rpm, and 2nd & 3rd gear performance.
Bad news: she's still misfiring under load definitely in 4th,... sometimes in 3rd as well.

Plan to put a few more drive cycles on her,... let STFTs stabilize; then reassess. With the leak resolved... hoping we can resolve the high load potentially d/t rich condition misfiring with tuning. If not, will go back thru the ignition system. :fingersx:

Suggestions welcomed.

I know people are against it, but I would try a gap-able plug down at 20 thousands (heat range 9 or 10). If the car doesn't misfire and pulls clean you can chalk it up to a weak ignition system. Once you have verified that the car pulls clean, you can either leave the plugs in an risk a ground strap failure or put the normal plugs back in and look for a better coil setup

Stroker, Thanks for the recommendation.

Yeah, I'm beginning to suspect coils. It was a bad coil ultimately that caused my electrical issues & sent her to the shop. My misfire is exclusively on cyl 2, which would "seem" to point to cyl 2 specific hardware, i.e. plugs, leads, coils, or injectors. And though I tested the coils..., I'm novice at it...and feel I m/h missed/ not interpreted something properly. I've read how accurately testing them c/b tricky. Think I need to cut to the chase...re-read the coil testing thread and test them again. :icon_tup:

Stroker is right on the money . If it misfires and isn't too rich , coils are normally the culprit . IIRC you switched from large gap BURs to small gap racing plugs and noticed a big improvement? That's pointing to weak coils as well. The D585s can be good but I know some guys have lots of trouble with them even when they test out ok. I wonder ........ is your earthing system up to scratch? I ran a large gauge wire from the battery earth direct to the coil earth and my 585s have been majic for many years .... could be worth doing.

I know we talked about this before but I can't remember if you did anything about it .Seeing that leak just reminded me. Is the end of this pipe still like it is shown here ? If so , I believe it's always going to be problematic.



https://cimg6.ibsrv.net/gimg/www.rx8...3c7a305f47.png

I'm going to re-test them..., but likely replace the remaining three original D585s. All indicators seem to point to suspect coils, AND one has already failed & been replaced. So, no sense dithering around with this...

Brett,. Yeah, you were right...that curved section is proving to be problematic to get & keep sealed.

If clamp is too loose... leaks. If clamp is too tight... section begins to buckle. I need to implement something different. I'm thinking replacing the existing reducer/ coupler w/ a 6 or 8" 45 or 60 degree coupler may help. And maybe apply a thin ring / band of Steelstik around the edge to reinforce it from buckling. :scratchhe Trying to avoid fabrication...

Thoughts?

Putting the bead all the way around , smoothing of the weld so it's even , then using a normal hoseclip will work . Won't look as nice ......but it will work.

I'll apply the Steelstik ring/band, but will try it with the T-bolt clamp first...as I like the look and for consistency. If I continue to have an issue I'll try the standard hose band clamp. :icon_tup: :fingersx:

It doesn’t help that you are trying to seal on the curved section of the pipe and not a straight section.
The silicone joiner looks a little loose on the fit where the finger is pointing as it looks pleated.

A full lip will help take up the slack and make the joiner a tighter fit. Also try a narrower hose clamp. Wider clamps will have different tangency and contact points around a curved pipe and will struggle to have a full seal.

Rotor, You're right. The section had buckled right where my finger is pointing. I had to reform the section there. Maybe that's what Brett was getting at, i.e. a narrower band, by suggesting using a standard band clamp, rather than the T-bolt clamp. Thx.

So, existing coils:
- 1 & 2 (cyl 1),
- 3 & 4 (cyl 2).

Coil #3 had been replaced by the shop w/an AC Delco type, and I'd been getting misfires exclusively on cyl 2.

1. I replaced positions 1, 2, & 4 w/ Standard Blue Streak (previously BWD) coils - lifetime warranty.
2. Kept the relatively new AC Delco, but moved it to position #1 (supporting cyl 1 now).
3. Wire brushed the frame location where the coil's ground strap terminates... to confirm a good connection.

Good news: Noticeable improvement in smoothness and acceleration. Oh, she spins now...the issue definitely was the coils. :ylsuper:
Bad news; Now I'm getting misfires exclusively on cyl #1. Lol Apparently the AC Delco coil installed by the shop is weak. Smh.

Tomorrow I'll test coils 1 & 2, but suspect the AC Delco coil is the culprit, and replace the weak link with one of the known good D585s, hopefully resolving the cyl #1 misfire.

Then its time to turn up the boost!. :yesnod:. Jk'ing. :yelrotflm

OMG...when she's right...she's tight! :bluesuit:

Replaced the AC Delco coil w/ a D585..., buttoned everything up, & went for a spin. She hasn't felt this good since last year...pre-rebuild!
- Starts from red-light / stop signs are like NA: smooth...no hesitations or surging. :nono:
- Idle, low speed, low rpm is smooth & composed. :yesnod:
- Acceleration is strong and consistent thru rpm range :D:
- And NO MISFIRES under 2nd - 3rd - 4th gear hard accelerations!! :ylsuper:

Next up ... need to put some drive cycles on her to ensure that performance remains consistent. Then perhaps I can turn attention to finalizing rad / IC set-up, and aesthetics...
.
https://cimg2.ibsrv.net/gimg/www.rx8...75943ac33a.jpg
.

Got in a few pulls in the cool of the morning...to validate my butt dyno that she's pulling near where she was last year...pre rebuild. Yup, the below #s are very near pre-rebuild performance. :ylsuper:

Below is a 3rd gear pull: 291 HP / 225 Trq smooth & solid at a nice safe 9 psi peak. :)

Couple easily resolvable issues:

1. Boost leak: Didn't "smoke test" the intake & charge sections & UIM. Sure enough...after changing the coils, etc. I've a leak ...likely in the same place. Still need to apply the bead / band of steelstik to the charge tube. Hoping that'll resolve this persistent issue. :fingersx:

2. Torque dropoff past peak: The corresponding AEM profiles show boost dropoff thru the rpm range. After resolving the above leak and via EBC tuning..., I'll try to reduce the boost dropoff, and consequently torque dropoff after peak (~5500 rpm). :yesnod:
V
V
https://cimg2.ibsrv.net/gimg/www.rx8...65701f8b8e.png
.

Last year's v-dyno overlayed w/ today's...

4Q18: 306 HP/ 225 Trq, ...@ 10.0+ psi
2Q19: 291 HP/ 225 Trq, ...@ 9.0+ psi (exhaust ported)

https://cimg7.ibsrv.net/gimg/www.rx8...f119b24490.png

.

She's driving great...per above posts. Switched to Pennzoil Platinum full synthetic and experienced an immediate improvement in starting (reduced cranking time cold & hot), smoothness of idle and rev progression. :ylsuper:

I've ~ half a dozen items on the hardware to do list..., but decided to pull the trigger on a bling item... :yelrotflm

https://cimg9.ibsrv.net/gimg/www.rx8...97355addc6.jpg

Drove about -400 mi one way to visit family. She's spinning like a top, ...growling like a big cat. :ylsuper:

In low 90's ambient temps, ...and giving her stick; temps remained rock solid:
- IAT: ~100 F
- Coolant: ~178 F
- Oil: ~180 F

~ 500+ more miles pushing her on this road trip before returning to the house.

Btw...first road trip...aah, yeah... I brought tools. :yesnod::yelrotflm


https://cimg9.ibsrv.net/gimg/www.rx8...169e3936ca.jpg
I
https://cimg5.ibsrv.net/gimg/www.rx8...bf3da6f220.jpg
I
https://cimg1.ibsrv.net/gimg/www.rx8...2652e18b95.jpg

Where’s the boost knob on this car, I’ll turn it up for you ... :)

It's plenty turnt................for now! She's a "jet" as is ...for the street. :yelrotflm

:jump:

Just returned from my first road trip...~900 miles. I literally couldn't be more pleased w/her driving performance.

My road trip encompassed three segments driven on three separate days, each with ambient temps in the low 90s. Vitals...ave coolant temp 180 F, oil temp 180 F, and IAT 100 F.

As an aside while traveling I had the opportunity to drive a Chrysler 300 SRT8 a good deal...4050 lbs., 425 HP, 420 ftlbs. Literally two tons of fun. :yelrotflm, ...but not my cup of tea. Felt like driving a humvee or tank. :boring:. Nice if you only intend to drive in a straight line I suppose. :dunno:

Then I hopped back into my 8 for the return trip. OMG what a difference... sublime agility! I intended to use this trip to ascertain mpg & range. Managed to drive civilly for one tank to determine her range is ~260 miles. After that... discipline thrown to the wind... :yelrotflm...I fell in behind a rabbit and averaged ~85 mph. She drove like... silk. Passing power is...nonchalant, nonplussed....down shifting is unnecessary. :smoker:

So, need to tidy a few engine related items, before turning to suspension and aesthetics. :yesnod: