thatsMR2u

iTrader: (19)

id take a good guess and say your boost gauge is wrong- 91 octaine would be seeing quite a bit of knock at those boost levels if you were datalogging

AF-Evo8

iTrader: (113)

i meant alky/meth injection to ofset the 91 **** gas

Aaron20

I have the AEM Tru Boost guage with the boost controller and it reads 25.3 steady while I a running down the track. I data log with my Utec ECU and it does not read any knocks on 91 octane. Is there something I'm missing and could possibly be harming on my engine?

Aaron20

oh, thanks

thatsMR2u

iTrader: (19)

go out and datalog a run starting at 2,000 rpms in 3rd gear and give full throttle all the way to redline, then compare the timing in your map to the timing you actually ran, if there is a difference then your stock ecu is pulling timing due to knock and the utec just isnt reading it.

And the reason the boost sounds offbeat is that evos will taper whether you have it set to 23psi it will redline at around 20. I had a stronger wga and could barely get my evo 9 20g turbo which was spiking to 28 to hold 24 to redline. I noticed you said you have cam gears which in turn you have cams- the larger the cam the harder it is to hold boost also.

There is 2 things i would check- if timing is fine- swap boost gauges (its so easy why not) with someone else and check to make sure yours is reading accurate, then if you have any local friends with evos- swap knock sensors (also check your knock sensor line to make sure its not pinches or frayed anywhere) then datalog timing and knock

evolution31

iTrader: (8)

I'm running 29 PSI on a stock motor, made 570 Whp 438 TQ. 93 Octane. The motor currently has 45K miles and is a daily driver.

Aaron20

I used the search function on this site and others and the only thing I found was someone talking about this from 2002, I have a 2004 that doesn't help me much. So if you don't have an answer to the question that I asked or don’t want to just talk about Evos in general then don’t put your 2 cents in. It's a legitimate question and there is no reason to mess up a thread if you’re going to say dumb stuff.

iTune

iTrader: (3)

you're correct, the head itself doesnt really care what boost pressures you are running. BUT, the head studs do! I would not run anything over 26 psi without a good set of ARP head studs. This will keep the head from lifting off the block at high boost pressures.

CJ

madmax199

iTrader: (20)

25 pound is what I run and would suggest to you, on stock head bolts. It is common wisdom that they are safe to about 26 psi but you always want to keep a margin of safety especially if you track the car. The only thing I find odd is that you can run that much boost with no knock on such low octane. If I where you I would find a way to inrease your octane rating if you plan to keep running 26 lbs or turn the boost down to about 21-22 lbs.

20psiMR

iTrader: (6)

Can run high 20's on stock turbo, but the problem is gas. I wouldnt recommend going over 21 psi on 91 PERIOD.

I was getting knock counts on 91 with a MILD tune on 20psi. Unless your just dumping fuel on the motor, there is no way your not seeing any knock with that kind of boost. Its just not safe anyway. Like someone else mentioned, tune correctly with timing/fuel instead of just turning the boost up.

sekula

iTrader: (31)

i run 27 psi on 110 octane and on my race tune, and for daily driving, i run 24 on 93 on my pump tune and run strong as hell w/out knock and have advanced timing about 3-4 degrees...going to run meth soon and going to run 27 daily with meth and meth tune