why does car stutter at high rpm??

[purpleesi]

well we finally got everything running right with the S-afc-II and the evo GT turbo at 16 psi. The problem is that no matter what we tried (we tried to tune it and it wouldnt tune), every time i reach 7000 rpm the car studders really bad and i have to let off the throttle. Up until then everything is running awesome...the o2 voltage and timing are both great.

Why would it shudder at only 7000+ even after tuning? Could it be my stock smic making my new turbo angry or is it something else? Does anyone have any ideas because id like to be able to use my last 500rpm.

Please give some input, that would be awesome.

Thanks

 

[Dtab123]

just a guess but sounds like fuel cut or rev limiter

 

[Spoolin4Ever]

plugs/wires?

is that the chinese made turbo? wonder if it's good or not...?

 

[oldman]

1. I took a look at your profile and I saw nothing which justifies you pushing the car beyond 7k, why are you pushing your car so hard. I would also suggest getting an afpr to keep that 255 under control.

2. You can very well be maxing out your stock injectors. Why are you using a safc with stock injectors? Where's the logger and what are you using to tune the safc with?

3. Check plugs and wires like already mentioned above.

4. If you have not perform a complete boost leak test after the turbo install, now would be a good time.

 

[purpleesi]

1. I took a look at your profile and I saw nothing which justifies you pushing the car beyond 7k, why are you pushing your car so hard. I would also suggest getting an afpr to keep that 255 under control.

2. You can very well be maxing out your stock injectors. Why are you using a safc with stock injectors? Where's the logger and what are you using to tune the safc with?

3. Check plugs and wires like already mentioned above.

4. If you have not perform a complete boost leak test after the turbo install, now would be a good time.

have not updated car profile in awhile.

im running 650's, aeromotive afpr, walbro 255hp, ngk plugs, and S-AFC-II.

the logger is a palmnstein.

 

[oldman]

have not updated car profile in awhile.

im running 650's, aeromotive afpr, walbro 255hp, ngk plugs, and S-AFC-II.

the logger is a palmnstein.

I would then go through 3 & 4 and go from there.

 

[Defiant]

Nothing "studders".