Have a look at the Turbosmart actuators also Aaron.
With a 22psi spring pressure they hold boost a lot better than traditional gates.

 

That's great power, my car just put down 416 on 91. I would like to see what your and mine would put out running on e85.

 

This was 3rd gear, we have pretty good traction on the rollers as of late.

I am not necessarily worried about holding more boost out the top since we are more concerned with the balance of efficiency (and outlet temp) and power (lowest outlet temp for a given boost level). I will look into them though since it makes it easier to get that boost where we want it to start with and then not ramp the boost crazy on the controller.

416 on what kind of dyno? Out of curiosity it was still a 2.0L or a larger motor?

 

Of course, that's why I install them with the 22psi spring pressure as it still gives them enough taper to stay in their efficiency zone, low enough base pressure to utilize the 'Boost drop on knock' system in the rom with a 3-port solenoid but still enough preload to work with.

They are in a league of their own with bigger FP and MAP turbos. Order them with 4 springs (26psi base) and just remove as necessary.

 

Any feedback on throwing one of the FP 84mm covers on this car Aaron?

 

416 on what kind of dyno? Out of curiosity it was still a 2.0L or a larger motor?[/QUOTE]


It was on 2.0, street run from a shop. Car has a GT30R in it. Also it was done in 110 degree. Said it would of put down more.

 

If we could still get them I think it would definitely benefit this car. On E85 it didnt seem to do as much but then again I had one car do 483whp on a stock cylinder head, stock IX turbo with cover, and JUN272s on E85.

I have tested it briefly on gasoline on 2.0L and the results were always good but not really crazy compared to what I had seen on cars without it. I have one to do in the next week or so that has already done 378whp on a stock VIII turbo with no cover so it will be interesting to see a IX and cover for comparison.

 

Good to know, thanks for the input Aaron. I am looking forward to your results on the 378whp car.

I recently grabbed a good condition, used FP 84mm cover that I will be throwing on a IX turbo with a heavily ported hotside done by ToxicFab. My car will be on 93 oct & the tune will be finished up on a mustang dyno, I am definitely interested in seeing my results...

 

Nice power. Will the car physically hold any more boost or does it just taper off up top regardless of boost controller setting?

It makes me curious about what is really controlling HP here. As boost goes up, peak HP happens sooner and goes higher and then it sits on the same descending line regardless of boost level after that point. Assuming airflow remains constant once you hit that peak HP, the descending HP then gets kind of interesting. Makes me wonder if HP would be flat but you are gaining frictional losses at that rate with RPM. If so, there could be some interesting gains by reducing friction in the engine and drivetrain. Actually, you might be able to make some pretty good estimates here of drivetrain losses.

Maybe its exhaust pulse energy getting choked and a better flowing turbine would hold peak HP longer? Maybe charge contamination is preventing adequate ignition advance and its killing combustion efficiency?

Either way though, my car did the exact same thing, making the same HP after like 6500 RPM from 16psi to 25psi peak. Looked just like that graph.

 

In most of the logging we have done in the past, backpressure increases with engine speed even at a static boost level. Mychailo can comment on it further (or he may have posted) but as I recall he was at something like 37psi of backpressure at 33psi on his BBK at peak torque (let's say 4k) but was 47psi at 26psi at peak power 7-7200.

In short, yes dilution and wont take timing nor boost on 92 octane.

 

BBK Full
4k rpm: 33 psi boost = 25 psi turbine pressure
7.5k rpm: 26 psi boost = 47 psi turbine pressue and 460 whp

HTA Green
4k rpm: 34 psi boost = 28 psi turbine pressure
7.5k rpm: 27.5 psi boost = 51 psi turbine pressue and 485 whp

In either case, turbine pressure holds steady to 5000-5500 rpm and then instantly starts climbing on a linear trajectory to the peak value at 7500 rpm. The bilinear response is rather interesting. I had always assumed it was a restriction issue in either the turbine or compressor flow, but an idle thought I just had is maybe its due to a change in airflow dynamics through one of the wheels. Probably not and getting OT...