524 whp on 93 pump, 629 whp on Q16

Event: Phil Grabow Hydra EMS Tune
Location: Element Tuning, Gaithersburg, Maryland
Ambient Temp: 68.92 degrees
Elevation: Sea level
Weather: Raining
Track and Conditions: NA
Tires: Michelin Pilot

I wasn’t really sure what to call this turbocharger as it’s based off of what we call the GT75 but this is a GT series housing with a Garrett 75 lbs compressor wheel and a Tial 1.03 exhaust housing. This was changed from the FP HTA since that was damaged (oil seals).

We made a little more power on pump 93 hitting 524 whp up from about 503 whp. It did spool a little slower than the HTA but had more top end. Very impressive for pump gas especially on this dyno!

On VP Q16 power was very good. There was some boost taper and overall we wanted more boost but that’s all the WG had in it. Upon further inspection we pulled the WG apart to upgrade the springs and noticed the diaphragm was folded over so this could have caused some issues. We’ll get stiffer springs in there and turn up the boost!

Target boost will be 35 psi which this turbocharger should have no issues running. Tuning went well and power came easily with boost. So far no sign of detonation issues as boost was increased or any other difficult symptoms. We did have misfire issues the last time the car was on the dyno but that was corrected with very tight spark plug gaps.

Car: 2007 Subaru STi
Tuner: Phil Grabow, Element Tuning
Dyno Info: Dynajet
Peak HP at RPM: 629.02@7600 rpm Uncorrected
Peak Torque at RPM: 405.94@6600 rpm Uncorrected
Baseline: 08 WRX 184 whp Uncorrected
Target Boost: 25-28 psi
Target AFR: 11.3
Fuel: 93, VP Q16
Engine: Cosworth Long Block
Intake: Cosworth
Turbo: Element Garrett/Tial 75 lbs T3 1.03
Header: GT Spec?
Exhaust: 3”?
Fuel System: 1600cc, A1000 Fuel Regulator and pump
EMS: Hydra 2.6 Engine Management
Driveline
Modifications: Exedy Triple
Suspension Modifications: Tein Coilovers

Again this setup has been similar to the other large turbochargers I’ve tuned with the Cosworth cams and or head package. It just doesn’t like variable cam timing advance but really big turbochargers like this are all about the top end.

On the next runs I may push the RPM a little further if oil pressure looks ok. For now I’m limiting the engine to 8k rpm but clearly it will make power to about 9k rpm

Thanks,
Phil Grabow

More information and discussion can be found here on NASIOC:  http://forums.nasioc.com/forums/showthread.php?t=1884618