Evo 7 wing, MR vortex generators, chop rear bumper, SE lip

 

evo 7 wing really lol

i have the vortex generators, jdm rear bumper, and just regular lip. idk how much the se lip really does, just the gurney flap planned for now. car did pretty admirably on track yesterday. i was a second off my pb but a lot of traffic and other bs. car is performing pretty consistently, so i need to figure something out with my driving more.

 

ok just rewatched my entire last session. probably 65-70 degrees ambient, so a touch cooler than what i've been at before.

it's still seeing a little bit of knock at the top of 4th, but only in one specific spot on track - coming out of a left hander that is a hard acceleration zone. any other spot on track, going from 3rd to 4th to 5th, no knock. i'm largely satisfied with this. i'm still on the 200 cel cat, and the 100 cel cat may help a touch.

what's a bigger concern is when ambient is going to be like 30-40 degrees higher...

 

You need to simply not run a cat.

Also a few 1-2 counts of knock isn't a big deal. The ECU is very good at pulling timing.

 

Agreed. Chasing 1-2 knock, even 3 is going to drive you insane.

 

That's where I'm leaning towards right now. Mechanically, what specifically is the cat doing, aside from hindering flow?

 

I was at Sonoma with 75* weather. I ran my "normal" tune which had the car peaking 28psi but decided to send it. I was in 5th gear twice. No knock, great sessions. Running e85 on the HTA71, no cat. Cats are killers for turbo cars, though... so props to you for making it work. That's a tall order.. I wish I could because I like how quiet the car is with a cat.

 

It's creating backpressure.

 

Especially on pump gas.

 

The 100 cel should help a bit. We chased the cat a lot with my car and in the end running a test pipe only at the track and then putting back on the HFC for street driving was the best compromise.