Here are the dyno results after I got my Osiris tune on my 2008 G37S 6MT coupe. The tune was done at Intec Racing in Kent, WA by Lawrence, the owner of the shop. The results are 303.5HP / 249.7 TQ on a DynoJet. The ambient temperature was 84F outside and 92F ambient in the shop.

Performance Mods list:
Stillen Gen 3 Cold Air Intake
Motordyne M370 Intake Manifold
Motordyne ART pipes V3
Fast Intentions Catback SS w/ 18" resonators
Southbend Black "Race" lightweight flywheel (10-12lbs lighter than stock)
Clutch Masters FX300 Segmented Kevlar clutch
UpRev Osiris tune


My next steps are to lighten unsprung mass by upgrading from my stock 19" sport wheels with something lighter and possibly switching to two piece rotors like DBA.

I definitely feel the increased power output of the engine. The results aren't as high as some users posted here and it doesn't seem much higher than my baseline I did 2 years back at a different DynoJet (Turbo Technologies - Tacoma, WA) which did 290HP/240TQ with just my Stillen Gen 3 intake. Did the ambient temperature play a role here in the final results? Lawrence had to let the car cool down a few times during tuning because it was so warm.

 

How many pulls did the tuner make on the rollers?

There are a lot of variables that will affect your results, including the air temperature. Remember, no car is created equal. Dyno results will also vary between tuners. It just depends on their experience/abilities and what they're trying to achieve. But it looks like your end result is on par judging by your baseline.

FWIW, it was 80 degrees when I got mine tuned on a Dynojet. 5 pulls later (including the baseline) and the end result was 314/275 with similar mod except I have HFC and no lightweight flywheel or clutch.

 

I wasn't too sure how many WOT pulls he made on the dyno that day. I remember him making pulls at varying speeds while he was tuning. He told me there was a lot of heat soak going on. He had to let the engine cool down several times during the tuning.

I think the only way is to take it back to a dynojet again to see whether or not temperatures played a part in the results since it's nice and cool now in the Pacific Northwest with the fall weather.

 

Not to bad on the numbers. You pretty much done w/ the performance parts?

 

Would you say that the Stillen Gen 3 Cold Air Intake gave the most gains out of all your addons?

Is the Motordyne M370 Intake Manifold worth it?

At what point should someone tune with addons with the above items?

 

You should tune once you get everything on or you run lean (or rich i forget which). The tune will make your car run better w/ the upgrades.

 

Is the graph the before/after with just the tune?

 

The best thing to do is get all the power adders you ever care to have on, then get a tune last to avoid re-tuning after every mod.

 

The graph is after an Osiris tune with all the performance parts.

 

I would say that the Stillen Gen 3 intakes helped a little in terms of performance but its not anything mind blowing. It gave me some extra power from mid to high RPMs at the cost of losing some low end torque. It also gave me an extra 2 MPG probably due to it running learner with the increased air flow. I had this as my only performance mod for 3 years (from 2010 -> 2013).

When I installed the Motordyne M370 this year, it made a noticeable difference in the character of the car. The torque was better from the low RPM range to just before redline. I started feeling the push to the back of the seat with the increased torque output. I was able to beat my buddy's modified 2012 Subaru STi (he had exhaust, test pipe, and 18 PSI boost on the stock turbo) with my mods: Stillen Gen 3 intake, lightweight flywheel, and Motordyne M370. I wasn't able to beat him before this.

A month after, I installed the Motordyne ART pipes and Fast Intentions exhaust. After the install, I noticed that I lost some low end power. So I knew I had to get a tune pretty soon after. I got a tune in August and I would say that it really made the car come alive with the mods. Even though 303.5 HP/ 249.7 doesn't seem that high, it feels like a completely different car with the sharper response and useable torque and power range.

Also, if you can, get a tune as soon as possible when you do your mods. Especially after you change out your stock CATs so I would save this mod for last. I was running really lean with a 16 AFR and there was detonation with my mods pretuned.

From the most effective to the least effective mods:

1. Motordyne ART pipes
2. Motordyne M370
3. Fast Intentions exhaust
4. Lightweight flywheel
5. Stillen Gen 3 intake

 

Thanks for the info and research. I will be doing something like this the next 2 months. (subscribed)

 

Just need to throw a couple comments in here. I think your numbers are awesome. You have to remember that 300 rwhp (assuming 15% drivetrain loss) results in a flywheel horsepower of around 353. Out of a 3.7L V6, that is damn impressive assuming 100% efficiency of 100 hp / liter. I think the next best thing for you to do would be to get more aggressive gearing. I don't know much about gearing and drive ratios but now that you are making some great power and torque, your going to want it available no matter what gear you are in at any moment so that you can slingshot your car through turns like a rocket. Look at the new z/28 for example. He is peaking at ~160 mph in the nurburgring video but through every turn before that the driver is able to stomp on the gas and launch himself through every turn because of the useable torque available.

Just my .02

 

The power in the car feels good. I'm able to get the VDC light to flash when I accelerate hard. Gearing would be awesome for acceleration. I think I may save for wheels and lighter rotors next to improve the looks of the car and to lose some unsprung weight.