M8 Turbo Stutters

[ratherbehunting]

I've got a 2010 M8 162"
I installed a Cutler stage 3 turbo
Had no success with the Attitude controller
Running a Redline controller for the secondary injectors
Using the stock ECU with a Power Commander V and Autotune for the primaries.
The build runs very strong except it has a stutter that starts about 3750 RPM, maxs at 4000 and goes away around 4250 RPM.
Clutch engages at 3500 RPM.

I run 70% AV gas and 30% 94 with no detontation.

This stuttering appears to get worse with altitude which makes me think its rich.
I changed the Air/Fuel ratios from 13.5 to 15 and it ran much better but still stutters at altitude (5,000 ft plus).
I've been watching my pyrometers and we are not going over temp in that RPM range.
NGK BR9 plugs look coffee and cream. Turbo side pyro reads over 100C cooler than the clutch side at times. Others times very similar. Clutch side plugs very slightly lighter than the turbo side.

Any suggestions?
Go to 16/1 AF?
My map jumps to 12.5/1 under boost which occurs at about 4500 RPM. I thought the A/F map would be kind of linear from 16/1 to 12.5/1 but it's looking like more of a step from 15 (16)/1 to 12.5/1.
Anybody got experience with this?

Thanks In Advance!

 

[jim]

Is it constant or intermittent?

I had a similar issue with my boondocker set-up with underhood intake. The hot air would send it into a rich bog-out that it sometimes would not recover from...same RPM range. Once I went to a cold air intake, I never had the problem again and the throttle response and overall power and all improved. Runs consistent day after day. And I can run less octane without detonation. Boondocker pump gas set-up, FYI.

 

[Hardass]

I've got a 2010 M8 162"
I installed a Cutler stage 3 turbo
Had no success with the Attitude controller
Running a Redline controller for the secondary injectors
Using the stock ECU with a Power Commander V and Autotune for the primaries.
The build runs very strong except it has a stutter that starts about 3750 RPM, maxs at 4000 and goes away around 4250 RPM.
Clutch engages at 3500 RPM.

I run 70% AV gas and 30% 94 with no detontation.

This stuttering appears to get worse with altitude which makes me think its rich.
I changed the Air/Fuel ratios from 13.5 to 15 and it ran much better but still stutters at altitude (5,000 ft plus).
I've been watching my pyrometers and we are not going over temp in that RPM range.
NGK BR9 plugs look coffee and cream. Turbo side pyro reads over 100C cooler than the clutch side at times. Others times very similar. Clutch side plugs very slightly lighter than the turbo side.

Any suggestions?
Go to 16/1 AF?
My map jumps to 12.5/1 under boost which occurs at about 4500 RPM. I thought the A/F map would be kind of linear from 16/1 to 12.5/1 but it's looking like more of a step from 15 (16)/1 to 12.5/1.
Anybody got experience with this?

Thanks In Advance!

Ecu and two different tuners holy cow what was wrong with the attitude? just curious as you have a lot going on there