05 STi with just an intake and exhaust

With and without a custom tuned Reflash
91oct

WHP and Torque:


AFR and Boost:

 

Do STI's always run that rich of an AFR??? if so, i'm glad i didn't buy 1...

 

Yeah. But stock EVOs run similarly rich. And you have on of those, don't you??

 

Don't worry bout HouseDJ. He thinks EVOs arn't rich stock and that humidity makes power, but only if its more then 85% humidity.

 

Don't remind me of the humidity, I was down for the ride for him, which was a mistake. -_-
Shiv, have you dyno'd an 06 sti on your heartbreak dyno?

 

i have 2 evos actually. i just figured that if 1 graph was tuned, that the AFR would be flat at 11.5:1 especially on 91. you guys can get more power out of it & still have no detonation...

 

where did you get that from? i am aware that stock evos run AFR's in the low10 to high 9 range.

 

Because you said " Do STIs always run that rich of a AFR" acting like the EVO doesn't run real rich.
Shiv interputed your statment the same.

 

Umm. not tryin to be a wise *** here but if he tunes for 11.5:1 what happens to his safety margin??? Oh right its gone and the Sti owner has to buy a new engine if he gets a bad tank of gas or the environment in which he operates the vehicle changes. Did we not see Stews (God help him) ordeal with that mail in flash with the lean conditions. Dont know if you intended it to sound this was but it looks like your giving advise to a Master Tuner.

 

Thanks, Shiv for posting about STIs for us defectors

Anyway, just looking at the graph, it seems like in this and other charts the upper RPMs falls off a lot faster after the tune compared to pre-tune. Not knocking the results, they are great. Just wondering if it is harder/less safe to get similar gains say from 5700 RPMs up. I am just comparing the downward slope of the pre- & post-tune charts.

Thanks!

 

One more question for Shiv. Are aftermarket intakes less/more/same effectiveness on an STI vs. Evo? I know you aren't a fan of replacing the stocker on the Evo, wondering if that opinion holds for the STI.

 

I think that has a lot to do with the STI's stock turbo. The compressor efficiency in that RPM range is somewhat.... lacking. You COULD push the turbo to make more boost in that RPM range and pick up a few HP, but you'd also end up with greatly elevated intake air temps. With the STI's predispositon against detonation, the conservative side to keep intake temps down is where it's at in my opinion.

- Steve

P.S. - The reason the torque is so massive is for a few reasons. The compressor can move more air in the lower RPM ranges allowing greater midrange boost and torque. Also, at lower engine speeds the cooling system is more effective in cooling the combustion chambers, this allows a more aggressive tune in that area without increasing risk substantially.

 

I hope your not questioning Shivs ability to tune STIs and his AFRs....I think he knows a thing or 2 about Subarus.

Nice job Shiv.

 

This graph might deflate my friend's ego quite a bit about his STI.

 

Reasons like that are why Shiv tunes for a living and HouseDJ doen't tune ****.