Chipped GT35r wheel causing rich knock......

[gsxrtalon]

Gt35r, 1050cc's, 255wally

Just recently before the Shoot out I did some work to the motor and the day before leaving MI for Ohio I rerouted my intake to the bumper to get intake temps down and I installed an air filter that was in my garage on the intake pipe down in the bumper. Well to my downfall and stupidity I never checked inside the filter and there were tiny metal shaving that once I got the car running had been sucked through the turbo, chipping the compressor wheel. I spent hours in Ohio(yes I drove the car all the way to Ohio and back)trying to figure out why once on the highway and my cruise set at 75mph my aem wb was reading 10.3-10.6 when prior to intake install it was during cruise 14.5-15.3. Well after trying everything and anything I finally got it home and took the FP intake pipe off and seen metal shavings and a chipped up comp wheel. My problem while driving down to Ohio was while crusing on the highway or at any speed for that matter once I started to build boost, even 1psi my WB would go straight to 10.0 and flatline and stay there and then the car would knock past 5counts(what my CEL is set for through Dsmlink).

Now the comp wheel wasnt hitting the housing but here is my question. With the comp wheel being chipped(every main bigger fin had chip marks on them....decent size gouges, some decent sized some small) would this make my A/F ratio different to the effect of making my car run super rich and knocking? It makes sense to me that since the comp fins werent completely smooth/flat/perfect that the turbo wasnt sucking as much air as the before and the ecu was dumping the same fuel as before therefore the A/F ratio went pig rich....

airflow dropped due to chipped/gouged fins but fuel delivery stayed the same as the previous tune.......this is my explaination. What are some others advice and thoughts.


I sent the turbo into FP yesterday to get a new 35r compressor wheel put on and have it balanced. I should have it back by next wednesday and on by the weekend to see if that was my problem.

 

[JusMX141]

I've never dealt with this first-hand, but my buddy's Frank 5 20G had chips out of (3) of the (6) compressor fins when we installed it....and the turbo's working fine. They're relatively large chips....two of them are about halfway down the fins, and one is all the way at the end. The turbo works fine, spools fine, pulls REALLY hard, and AFR's are 14.7-15.3 at cruise.

I also had a guy using a Small 16G on his Honda that didn't have an undamaged fin left on the compressor wheel- I mean it was MANGLED- and it still worked fine as well. It sounded a bit strange, but still made 10psi strong.

Now these are both journal-bearing turbos; I'm not sure how crucial chipping is to ball-bearing units.

 

[propeine]

If you were on a speed density setup I'd say it might cause you to run rich but being on a MAF a little decrease in airflow through the turbo shouldn't cause your AF to change. The MAF should pick up on that.

 

[gsxrtalon]

The car was running good with very minimal knock at 18psi. Once I installed....IPT converter, prothane mounts, new knock sensor and rerouted intake to pipe the car ran ok in vaccum and in slight accelleration but once it boosts aem goes straight 10.0 and the car builds boost super slow and only makes 8psi then knocks really bad.
All these chips were on the edges of the fins also.

If it is not what has caused my a/f to change and knock then I am completely lost as to what changed everything.....

 

[dsm-onster]

If the turbo flows less air then your engine control system will know it. Speed density or not. Boost will be less, massflow will be less. You have another problem causing this.

 

[gsxrtalon]

any ideas? All I did was just as stated above and then the car started running like crap. Maybe a head gasket?? Ill do a compression test once I put the turbo and manifold back on and do a boost leak.

 

[dsm-onster]

I'm at a loss. I'll be thinking about your problem. . . This is the right place to post your issue. We usually solve problems around here. just keep working at it .

A blown head gasket would cause rich issues because the fuel isn't burnt properly or at all. But you won't be getting knock from it. . .

 

[propeine]

You would have had to move the MAF around when you did your intake install right? Could something have gone wrong with either the wiring or the MAF itself?

 

[gsxrtalon]

I have a FP 4'' inatake before and I picked up some 3'' pipe from auto zone to reroute to the bumper. the new pipe is a 90degree elbow and a 6in. piece into the bumper....all 3in. Again no prblems before the installs of the converter, knocj sensor, mounts. We only took off the intake pipe and UICP.