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Old 03-28-2014, 07:21 PM   #88
user1029
Scooby Specialist
 
Member#: 57064
Join Date: Mar 2004
Vehicle:
2008 STi IAG built
HTA86 E85 Kel272s Cos IM

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Not the exact ideal comparison due to differences in boost that was negated by differences in temperature but you get the idea :tup:

Driving impressions after Cosworth IM:

1. Turbo spool sounds 25% louder

2. Drives like stock at part throttle just like before.

3. Yes, the lag is definitely noticeable at WOT tip-in but it is not a deal breaker at all. The fact that I went with an HTA86 turbo, big heads/valves/cams already means that I am too far gone at trying to hold on to any low end. Might as well make the most of the top end!

4. The top end, oh yes the top end Basically I picked up 23-26whp/11wtq at every single rpm after 4500rpms according to the dyno graph. The top end is just downright BRUTAL now :tup:

5. Would I recommend the Cosworth IM? I would ONLY advise it to people with turbos at >70lb/min + headwork + running >30psi AND who operate at high rpms for lengthy periods (road racing or drag).

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This is the interesting graph on straight 93 octane, boost is the same but varied greatly on ambient temperatures.



Impressions:

1. Even at 25psi, the Cosworth IM is still not able to "wake up". There are huge losses of power down low and shifting of the curve to the right.

2. I wouldn't say I lost power with the Cosworth IM because you have to account for the temperatures differences in the tunes but certainly the benefits of the Cosworth IM on low boost are marginal at best.

3. The OEM STi manifold is fantastic and I would recommend keeping it if you are not building a drag/road racer.



My mods for reference:
IAG V-band rotated turbo kit
- HTA86 0.82 Tial V band housing
- IAG FMIC kit with Spearco core and bumper beam
- IAG 4" Intake
- IAG V-band Uppipe
- IAG V-band Catless Downpipe
- Tial 44mm External Wastegate with open dump
- GT Spec Equal Length Headers V-band with Uppipe
- Harman Motive Catback Exhaust
- Aquamist HFS-6 running Boost Juice (50% methanol/50% water)
- Injector Dynamics 2000cc injectors
- Aeromotive 340lph Fuel Pump
- Aeromotive Fuel Pressure Regulator
- IAG Fuel Rails
- Grimmspeed Electronic Boost Control Solenoid
- Grimmspeed Thermostat
- Mishimoto Radiator
- Tial Q BOV
- LFR7AIX Spark Plugs
- IAG Catchcan
- Stock Air Pump deleted
- IAT sensor and 4 Bar MAP sensor
- Cobb Accessport Speed Density protuned by Jorge

IAG Stage 2 Bottom End (25,000 DD miles and counting... Built by Artie at IAG)
- Manley Platinum Series 99.5mm Piston Set
- Manley H-Beam Rods
- ACL Main and Rod Bearings
- OEM Nitrided Crank
- OEM 11mm Oil Pump
- Killer B Oil Pickup with Baffle
- Gates Racing Timing Belt Kit
- 12,000mile/1year warranty

IAG Stage V Heads (25,000 DD miles and counting... Built by Artie at IAG)
- Flipped Cosworth Manifold with retained Air Conditioning
- ARP2000 Head Studs
- OEM Headgasket
- Manley Extreme Duty 33mm Exhaust Valve Set
- Manley Race Flow 37mm Intake Valve Set
- Manley Valve Spring and Retainer Kit
- IAG Stage V headwork with Multi Angle Valve Job/Port&Polish
- Kelford Dual AVCS 272/268 11.30/11.50mm Lift Street Cams
- Cosworth Phenolic Spacers
- IAG TGV Deletes
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