New owner, just picked up a modded Evo IX last week and I'm wondering if it's overboosting. It will spike to 25 psi briefly and then hold 23 psi in all gears but 5th. In 5th it will spike to 26 then hold 25 psi for an extended period before tapering. Previous owner says it's professionally street tuned for 23 psi on 93 octane. I can only get 91 octane here so I've turned the boost down 2 psi for now. I'm considering leaving it turned down or turning it back up and running octane booster since it's not a daily driver and that wouldn't be cost prohibitive. Am I hurting my engine at that higher setting? I've never heard it knock but can you always hear it?
Mods:
TBE with no Cat, K&N cone filter, MBC.
The psi readings are from a Defi boost gauge. Could that be over reading? Thanks for any input.

 

I would have it retuned for your gas, just to be on the safe side.

 

+1 on the retune for your gas....i think once u get use to it, you def know when timing is being pulled(knockin)....but wouldn't count on that as a good way to determine..thats what sensors are for

 

Short answer, yes. By the time you actually hear knock on a forced induction motor your engine might already be damaged. It's not like a naturally aspirited engine where you can hear it knocking. Find someone to retune it for you. It shouldn't take much of an adjustment.

 

What if I just use the octane booster to bring me back up to 93 octane? Do those numbers sound like a safe tune for 93? Thanks to those that responded.

 

+1 on having it either retuned or at least have somebody take a look at it.

 

If you are talking about octane booster that you buy in the store it would take a lot more than you think to go from 91 to 93. Like 10 bottles or so as a rough guess. You don't want to mess with that stuff anyway. If you are set on not bringing the car to anyone, download evoscan, buy a wideband and log the thing yourself. You can then tune it yourself or do an email tune with someone, like me for instance.

 

once you have a retune your gonna be fine. Right now mine will spike to about 26 if i punch it in 3rd, if im going at the strip from a digg it might get to 24. But i cheat, I have meth, lol.

 

I'll look into a retune. I'm in the middle of nowhere Canada so it'll be a long drive to get it done. Maybe I should look into that meth kit as well since it will suck to decrease tune now that I know what 25 psi feels like.

 

Use a higher octane of gas till you get it retuned on 91... if you have no access to race gas then lower the boost

 

yeah i agree with everyone else. don't be lazy and just get a retune. i drove 5 hours once just to get a retune and it's worth it in the long run. plus you'll feel better going ***** out, knowing your motor won't break on you.

 

drop24: I´m curious. Do you happen to know who did the tune on your car?

 

What does it taper down to at redline?

 

I have crappy 91 octane too, I'm only running 21 psi, and it'll hold around 19 til redline. But I know my engine is safe.

 

Sparky, It was Innovative tuning in Buffalo, NY.

I've turned my boost down. Spiking to 23 and tapering to around 18 now. It's a little bit more in 5th so I'm not going WOT in 5th anymore.

5hrs eh? For me it will be a minimum of 14 hrs drive.