Miata Turbo Forum - Boost cars, acquire cats.

Miata Turbo Forum - Boost cars, acquire cats. (https://www.miataturbo.net/)
-   ECUs and Tuning (https://www.miataturbo.net/ecus-tuning-54/)
-   -   Issue when coming into boost (https://www.miataturbo.net/ecus-tuning-54/issue-when-coming-into-boost-97326/)

Ramennoodles 06-26-2018 04:01 PM

Issue when coming into boost
 
hey guys,

first real post other than my meet and greet, and I already have an issue with my car.

My car is a 90, with a mspnp2, rx8 injectors, ls coils, colder plugs gapped at .030, stage 3 clutch and lightweight flywheel. Car ran fine for a while, but had a faulty temp sensor (the green guy on the back of engine) and when I replaced that I also swapped to a bmw tps.

After getting it back on the road, I have a strange issue where I can drive normally under 3k rpm, but when I get above that, I can hear the boost building normally, for a second, once it gets about 2 psi though it makes a much louder hissing/scratching noise, and it goes no where. Boost still builds (very quickly compared to how it did prior to changes) and will peak at 10psi, but the car goes no where. Rpms DO NOT INCREASE past 5k. This happens in every gear.

what I’ve been thinking: this is a street tune, done by me. I don’t have a whole heck of a lot of knowledge on tuning, but I use VEAL. AFRs are 9.6-10.1, which is ridiculously rich, and I notice my spark map is more conservative than most I’ve seen, (18.- at around 120kpa) could these together cause this?

second thought: clutch badly slipping/installed incorrectly. I don’t think this is it, because rpms do not increase, and I do not feel any jerking like the clutch is slipping then catching.

sorry for the long winded post, any help would be appreciated

Attached is a pichttps://cimg3.ibsrv.net/gimg/www.mia...58199afed.jpeg
took of the area it was the worst on my data log, not at home right now but will post data log from a ride around my neighborhood if people think that would help when I have the chance

Ramennoodles 06-26-2018 04:03 PM

Also take note, in the log you can see tach signal jumping up and down while rpm slowly increase, I didn’t feel it in the car

ryansmoneypit 06-26-2018 05:10 PM

post a log pulled from when it happens.

Braineack 06-26-2018 05:19 PM

9.5 AFR in light boost. motor is flooding.

Ramennoodles 06-26-2018 05:51 PM

I will tonight when I’m out of work, and Brain that’s what I was thinking, because as soon as boost comes in it’s pegged to around 10 afr. But the loud hissing/scraping is what’s confusing me, when it happens I’m not backfiring or anything, so I wasn’t sure if that’s the only culprit at work here

Braineack 06-26-2018 05:59 PM

usually that rich makes a farty noise.

take vid so we can hear.

Ramennoodles 06-27-2018 10:11 PM

Here’s partial and full throttle videos, the partial all sounds normal, full throttle video you can hear the loud noise a little better, but in testing today, I found more issues, my internal wg opens around 8 psi, but in the video you can see it creeps up to 12ish, max creep I saw was 16 psi so I have that issue to correct. Pulled some fuel out and still running rich, will post data log ASAP. Ignore messy interior, car is still in its infant stages



the sound is vey hard to hear via video

Ramennoodles 06-28-2018 04:38 PM

Omfg shoot me, I’m a f——— idiot. My wastegate is opening way sooner than it did in my prior set up, around 3500 rpm, which is the cause of the strange noise. The strange noise is just my wastegate opening sooner than expected. Then the car falls on it’s face because boost is slowing creeping up beyond that point and not building like it did prior to 3500 rpm. Brb gunna go hang myself before you guys castrate me :bang:


All times are GMT -4. The time now is 12:24 PM.


© 2024 MH Sub I, LLC dba Internet Brands