- Joined
- Jun 26, 2002
- Location
- Apache Junction, AZ
Ok so after talking to my machine shop who put my head together I am trying to figure out why my b230 seems to have issues going over 6000pm.
My setup is b230f w/ upgraded rods
2mm larger intake and exhaust valves with yoshifab springs and retainers from the group buy with new seats and light port work
Custom intake manifold (NIW) and custom header with a 38mm tial external WG
HY35CW w/ WG hole welded closed
MS2 running LS coils
I am running 27psi on this setup with 1700cc injectors on E85 with more than enough fuel pumps.
200r4 transmission (nearly same gear ratios as AW71)
3.5" exhaust turbo to tail
AFR's are good under load, injectors are in the 80% DC range at 6000rpm.
So what we have been thinking is that either the 9cm2 (.54) turbine housing is way to small causing some kind of back pressure issues or i am getting some kind of valve float at that rpm. Being that I have the yoshfab springs I am doubing that is the issue. In 2nd gear the car seems to rev out to 6400-6500 (I need to go back and look at the datalog from todays testing) or so and then hit a wall, in 3rd I can stay in it but 6000rpm just seems to be the limit the car can do when in 3rd. In looking at the datalog nothing stands out besides the engine just seems to stop climbing RPM wise. I guess I can see over time how the rate of acceleration of the engine changes. rev limiters in MS are all set to 7100rpm or so, nothing has changed since the old setup on the limiters.
I am trying to get ideas if this turbine housing just seems to small at these power levels(bench racing math puts me around 500+bhp after maxing out the 1000cc injectors on E85) or if valve float with upgraded springs and valves are the cause, I know that the valve train might be a little heavier than stock with the larger valves but not this bad. With my old motor and stock head i could hit 7100pm no issues with the same turbo, and MS setup but that was on a stock head and 8.7:1 CR vs the 9.8:1 and extra head flow from the valves. I have also added 2psi over my old setup. I can tell you that so far this current setup with the healthy short block (higher CR) and big valve head sure feels worlds faster than the old setup. Even 15psi feels light years smoother and faster than 20psi did on the old setup.
I have a GT3582R sitting here that needs a turbine housing so I am thinking I need to just go about getting that thing installed sooner rather than later as I am looking at .82 a/r housings for it just to make sure I have the flow up top.
let me know your thoughts.
My setup is b230f w/ upgraded rods
2mm larger intake and exhaust valves with yoshifab springs and retainers from the group buy with new seats and light port work
Custom intake manifold (NIW) and custom header with a 38mm tial external WG
HY35CW w/ WG hole welded closed
MS2 running LS coils
I am running 27psi on this setup with 1700cc injectors on E85 with more than enough fuel pumps.
200r4 transmission (nearly same gear ratios as AW71)
3.5" exhaust turbo to tail
AFR's are good under load, injectors are in the 80% DC range at 6000rpm.
So what we have been thinking is that either the 9cm2 (.54) turbine housing is way to small causing some kind of back pressure issues or i am getting some kind of valve float at that rpm. Being that I have the yoshfab springs I am doubing that is the issue. In 2nd gear the car seems to rev out to 6400-6500 (I need to go back and look at the datalog from todays testing) or so and then hit a wall, in 3rd I can stay in it but 6000rpm just seems to be the limit the car can do when in 3rd. In looking at the datalog nothing stands out besides the engine just seems to stop climbing RPM wise. I guess I can see over time how the rate of acceleration of the engine changes. rev limiters in MS are all set to 7100rpm or so, nothing has changed since the old setup on the limiters.
I am trying to get ideas if this turbine housing just seems to small at these power levels(bench racing math puts me around 500+bhp after maxing out the 1000cc injectors on E85) or if valve float with upgraded springs and valves are the cause, I know that the valve train might be a little heavier than stock with the larger valves but not this bad. With my old motor and stock head i could hit 7100pm no issues with the same turbo, and MS setup but that was on a stock head and 8.7:1 CR vs the 9.8:1 and extra head flow from the valves. I have also added 2psi over my old setup. I can tell you that so far this current setup with the healthy short block (higher CR) and big valve head sure feels worlds faster than the old setup. Even 15psi feels light years smoother and faster than 20psi did on the old setup.
I have a GT3582R sitting here that needs a turbine housing so I am thinking I need to just go about getting that thing installed sooner rather than later as I am looking at .82 a/r housings for it just to make sure I have the flow up top.
let me know your thoughts.