I got inspired by this thread that was created because of a thread I made about a customer with a Evo 9 that I had tuned at 24.5 psi on 91 oct gas:

https://www.evolutionm.net/forums/sh...d.php?t=328285

So this week I found some extra time on my hands away from my hectic life to try some stuff out on my personal Evo 8. After all, why should 9's have all the fun?

Tonight I dialed in some more boost on my 91 oct map. I usually run 100 oct 24/7 but since it's snow season in Tahoe I've been running 91 oct for the 3.5hr drives to Tahoe to get my fix. My 100 oct map ran 26psi.

Since my personal Evo 8 is my Evo R&D test-bed I figured why the hell not, let's dial in some more boost!

Tonight I got it up to 25.4 psi on California 91 oct gas with no knock whatsoever. It really transformed the car. It feels almost as quick as my 100 oct @ 26psi map I usually run. I loaded tephra's knock CEL rom so I could keep tabs on my knock count after setting the tune:



I'm currently running just a drop-in filter. I usually run a open filter, which will hold more boost, but I lent the open filter to a customer since we where out of stock at the time. I have an extra open filter in my garage that I am going to install this week to do higher boost in the higher RPM range testing.

Anyway. As you can see there is no knock at all at 25.4 psi on California 91 octane gas. The car really transformed power wise. I am going to keep pushing my little Evo 8 test mule to see how much boost I can get out of 91 oct. I will also put it on the dyno so we can actually quantify my butt dyno feelings.

After I set this 25.4 psi tune I closed the laptop and went for a drive for 2 hours beating the hell out of the car trying to get my knock CEL to come on. It only ever came on when I bounced off the rev limiter, which I did a bit since the car pulls much harder now.

I'm going to up the boost some more this week and I'll keep updating this post with my findings...

 

hey man, looks good, what are your current mods on the car...?

 

I guess that would help eh?

Current power mods:

2005 Evo 8 MR

FPgreen turbo (non-ported)
IX wastegate actuator
Stock exhaust mani (non-ported)
Stock 02 housing (non-ported
HKS 272/272
HKS cam gears
Denso 720 cc injectors
Walbro fuel pump
ETS 3.5 FMIC
2.75 DP
Test Pipe
3" catback
Nisei LICP
BMC drop-in air filter (usually open filter)
8 heat range plugs

 

Do you have head studs on this 8?

 

Yes I do, ARP

btw, I am going to be freshening up the head soon, which is another reason I am doing this. Since the head is coming off soon, I don't really mind if I pop a headgasket in testing. But so far, no knock!

 

UHHG!! Should I be replacing my stock head studs on my IX? Seems NO one has concrete evidence of this needing to be done on the Evo...

 

I have the same exact mods as you but i have a ix ...

3" dp, and ETS 3"..... anyways the fp green turbo is coming this week... any recommendations ? as far as power wise before installing, or doing anything before the install...?



Thanks Man....



BTW: if you dont mind, do you do your own tuning...?

 

port the turbo/exhaust mani before installing. Tubular 02 housing, etc

Yes I do my own tuning.

 

 

At "normal" pump gas levels, which is changing every day at this point however, I don't see it being needed.

I honestly don't think the stock turbo flows enough to lift the head on stock studs. Detonation will however.

 

Sorry for taking this off topic... Going to PM you to keep this thread on track...

Cheers-
Erich

 

That is a mean hump of power.
This gives me courage to try...looks like you ramped up the boost to keep it from spiking and having to go negative on timing at peak load.

 

I suspect your cams, intercooler and green add knock resistance.

 

mind me asking your cam gear setting? I've noticed that the settings play a big role in knock activity. As I recalled I think you were something like +1/+1 or thereabouts. I ran +2/+1 for quite a while, which gave a great kick, but knock noise everywhere. I recently changed to the infamous -4/-1 (for lack of a better idea) and knocksums dissapeared, so this is why I ask.

 

bryan, after I see some before and after dyno graphs I may want you to add a bit more boost to my 91 oct map.