So the car is AP1 Turbo with a Pfab elt kit gtx3076r id1300 450lph stock engine brand new head gasket. 3”dp to 3” boost cutout and a stock exhaust. Tuned by evans in September on a 80* day. Flex fuel dialed in on Kpro v4. Car made 540@19 psi on e70. Ran great for 2 months.

Car suddenly started hitting what seemed to be a 2 step at 6600rpm every time I hit boost back firing and not passing 6600rpm. Took a look under hood hondata boost controller one wire was about to break off. Replaced with a Mac 3 port (the same exact thing). Took it for a spin with same results. Plugs were perfectly fine iridium br9’s gapped at .019. Replaced anyway. Same results. Noticed if out of boost and close to 6600 rpm it would just bounce rpm at 6600 like you’re at the rev limit but very slowly and not go any higher.

All vac lines seem ok wastegate had black soot in the spring area. Cleaned and check function seemed “ok” diaphragm def had wear. (From previous turbo kit tial v44) disconnected boost controller and car made 10psi off spring but wouldn’t pass 6600rpm again.

What sensors would put put a limp mode type 6600rpm limit on the car. Also I have to check function of boost cutout not sure if it’s opening anymore.

Any other suggestions I’m sorta lost. Evans looked at a datalog and said tune is spot on. Afr stays perfect

car hits overboost cut at 23psi also if you hit full boost before the 6600rpm also and has a very sensitive partial throttle overboost.

 

 

Sounds like boost cutoff to me. Misses are slightly more subtle whereas b. cutoff is violent like a 2step.

If youre breaking up up top you can lower the gap a little more. When you say br9 are you referring to these: BKR8EIX? If you have an 8 cold rating plug you can gap them down to 0.017.

If youre hitting boost cut, try lowering the boost duty cycle 1%. Since evans said afr and everything looks good, im betting the colder weather is causing you to see an increase in boost.

 

Dude thats a lot of soot in there, r u running really rich? Anyway, sidenote you should be running at least one step colder 8 plugs, not 9.
And get a new solenoid if im reading your thread correctly. That doesnt look salvageable.

 

I replaced the boost solenoid already. not running rich at all, that wastegate is old and from the previous setup that was on the car. I cleaned it all out and the diaphragm looks worn but no rips or tears. I’m gonna check my vac lines as they are close to manifold and have a plastic Tee in the line going to the boost cutout and the wg and boost controller possibly it could have melted on the inside causing my issues.

as for plugs im using BKR9XI. You’re suggesting to go one step hotter back to an 8. I figured at my boost levels I should be 2 steps colder.

 

im sorry, i misunderstood you. Heat range 8 or 9 should be okay. I dont think thats the problem tho. Most likely youre overboosting. Definitely double check all your boost/vacuum lines. Especially the ones coming off your wastegate or nearest the manifold. My vibrant plastic pushlock fittings and polyethylene tubing all melted, also my buddys evo10 plastic tubing also melted on the dyno today. Replace them with regular barb fittings and heat resistant rubber hoses.

 

Send me a log showing the cut and your tune.


Jmpaintcorrection@yahoo.com

Ill look it over and see if I see anything.

Ive fixed quite a few s2ki owners tunes over the past few months since i started offering help.

 

You need to adjust the secondary boostduty table so it pulls duty % off the base boostduty table in correlation to the IAT. You were tuned at 80 degrees. Its getting cold. Air gets more dense and you start making more boost. going from 19psi hot to 23psi when its cold sounds about right to me. I was at 16psi and was hitting boost cut at 20psi once it got cold because I didn't have my secondary table setup.

 

ill send it to you tonight when I get home from work. Thank you for the help

 

according to the log your only hitting 15.5 PSI..

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