Hi guys.

I want to know...how much more PSI can the stock turbo of the X can take?

I have the AMS manual boost controller, AMS UICP, AMS SRI and custom Magnaflow catback.

I want to put more psi....but I don't want to kill my car...

so what would be reasonable?

thanks for the advice

If you dont have a tune then the ecu limits you at 25 psi, but there have been people that run 30psi pretty easily and xtremeboost even ran 40psi

If you dont have a tune then the ecu limits you at 25 psi, but there have been people that run 30psi pretty easily and xtremeboost even ran 40psi

Damn i cant wait to get one of these cars

acourse you can dmg your engine at your own risk at those psi :)

so...I can run the car with no problem at 20 psi with no tune

I've been at 23 psi for a few months. Get up near 26 and you risk limp mode kickin in.

so I'll put it at 20 psi and I'll be ok!

isnt factory like 21?

I heard that it was more like 14-15 psi????

i cant remember but its not less than 18. pretty sure its 21

yeah you're right...it's 21. But not all the way through the power band.

anyway...I'll just give a turn on the AMS MBC.....so this way..I'll be safe

yeah you're right...it's 21. But not all the way through the power band.

anyway...I'll just give a turn on the AMS MBC.....so this way..I'll be safe

do you have a boost gauge? im running 25... well i was before my DP. didnt have any problems at all

Its not 21 psi the whole way because of the wastegate not holding it. Do you have a boost gauge with ur MBC? and yea stock is around 21 22

no...my MBC is not yet installed.

I'll have to find a boost gauge!

but... do you have picture where you fixed your gauge?!?!?!

right on the steering column like everyone else lol. its a little of center towards the tach

http://www.evoxforums.com/forums/showthread.php?t=7881 I mounted mine there and i will mount my wideband there to but i think im gonna change to a black face.

Factory will peak around 21 psi, but tapers off.

It's not peak boost that kicks the car into limp mode. It's the airflow vs. MAP vs. RPM.

We've ran 29 psi @ full TPS runs without and issue, but I can kick a check engine light on one @ 24 psi feathering the throttle at full boost.

ok...thx!!!

so to conclude...what is the safer highest boost for stock ecu with UICP, SRI and magnaflow catback?

someone can answer me please?

I will not re-tune the ecu....I will run the stock ecu with the mods mentionned in the previous post...so how many psi can I add with my AMS manual boost controller to have a little more power....but still be safe.

You'll be good with 22 or 23 lbs!!!

someone can answer me please?

I will not re-tune the ecu....I will run the stock ecu with the mods mentionned in the previous post...so how many psi can I add with my AMS manual boost controller to have a little more power....but still be safe.
To stay safe 23psi on 93oct.

the stock turbo seems to stop making power round 28psi... most every high horsepower stock turbo x is running 27-28psi.

edit: and alot of these people are running 28psi on pump gas..

I am wait on parts for alot of those people that are running 28psi on pump. Yes they are doing it now with no problems but wait something is gonna give.
In turbocharged engines there is a fine balancing act when it comes to making a lot of power on low octane fuel. In most cases, ignition timing must be retarded as the boost pressure rises above a critical point and finally there reaches a further point where the engine simply loses power . If the timing was not retarded with increasing boost, destructive preignition or detonation would occur. Normal combustion is characterized by smooth, even burning of the fuel/air mixture. Detonation is characterized by rapid, uncontrolled temperature and pressure rises more closely akin to an explosion. It's effects are similar to taking a hammer to the top of your pistons

I am wait on parts for alot of those people that are running 28psi on pump. Yes they are doing it now with no problems but wait something is gonna give.
In turbocharged engines there is a fine balancing act when it comes to making a lot of power on low octane fuel. In most cases, ignition timing must be retarded as the boost pressure rises above a critical point and finally there reaches a further point where the engine simply loses power . If the timing was not retarded with increasing boost, destructive preignition or detonation would occur. Normal combustion is characterized by smooth, even burning of the fuel/air mixture. Detonation is characterized by rapid, uncontrolled temperature and pressure rises more closely akin to an explosion. It's effects are similar to taking a hammer to the top of your pistons


well i have watermeth injection and i am hitting 28psi and holding 24-26 down to 22 at redline (i think) ... a couple of the guys in florida have 30+ thousand miles on 28psi with pump. all basic boltons and most none of them are running meth.. just 93 oct and a killer tune. it does seem crazy.... but oh well... mitsubishi built a killer motor.

the Perrin cobb mail in tune spikes 29psi.. on a mail in flash.. on pump...

I am wait on parts for alot of those people that are running 28psi on pump. Yes they are doing it now with no problems but wait something is gonna give.

Aside from a mechanical failure, there's no reason that the engine can't handle this with proper tuning/supporting mods. Yes, if it sees extremely high boost over and over it could lead to failure but that would be on a case by case basis. Shops have already proven the stock internals are handling low 400's on 93. Hypothetically, the engines might last 4 years instead of 5 (not actual timeline), but it's splitting hairs at that point.


In turbocharged engines there is a fine balancing act when it comes to making a lot of power on low octane fuel. In most cases, ignition timing must be retarded as the boost pressure rises above a critical point and finally there reaches a further point where the engine simply loses power . If the timing was not retarded with increasing boost, destructive preignition or detonation would occur. Normal combustion is characterized by smooth, even burning of the fuel/air mixture. Detonation is characterized by rapid, uncontrolled temperature and pressure rises more closely akin to an explosion. It's effects are similar to taking a hammer to the top of your pistons

I mostly agree with this. I would define detonation as fuel/air mixture igniting while piston is moving upward to ignite mixture but mixture ignites before piston hits proper degrees BTDC of that stroke. With proper tuning/supporting fuel mods the car can be taken to the limits of 93 oct without this occuring. But then water or meth can be added and push the limits of 93 even further- but that's a different subject entirely.

To stay safe 23psi on 93oct.

so here we only have 91oct.

so I guess 19-20 psi is enough?

:thumbup:so here we only have 91oct.

so I guess 19-20 psi is enough?

so here we only have 91oct.

so I guess 19-20 psi is enough?


you wil be fine with 23 on 91.. the car run plenty rich from the factory, its was intended to be driven with 23 psi on 91 in cali.. so i am sure you will be fine.

well i have watermeth injection and i am hitting 28psi and holding 24-26 down to 22 at redline (i think) ... a couple of the guys in florida have 30+ thousand miles on 28psi with pump. all basic boltons and most none of them are running meth.. just 93 oct and a killer tune. it does seem crazy.... but oh well... mitsubishi built a killer motor.

the Perrin cobb mail in tune spikes 29psi.. on a mail in flash.. on pump...

U are running meth so its okay to run high boost, its just like running race gas all day. I am talking about the guys who run high boost with out properly monitoring the car.
28psi on 93oct u say thats a Killer tune..... yes that is a very aggressive tune. Well we all know the saying, if u want to play u gotta pay. Eventually there are things that are going to go on the car.

at what gear will it show the true boost, for me at 3rd it shoots up to 17 or 18, but in 5th it shoots up to 19? when i was running stock...in 5th it would shoot up to 20, 21 psi, do u recommend turning up boost? mods i have ams uicp; ams intake; greddy downpipe; ams testpipe; and straight pipe exhaust; and a hallman mbc.... what would you recommend i turning the boost up too without blowing anything.

Would a MBC be useful if my tuner already has stock boost set at 25 psi and tapering using Ecuflash?

Would a MBC be useful if my tuner already has stock boost set at 25 psi and tapering using Ecuflash?


would not worry about it, will throw your A/F's off