well, my IX MR is hitting a peek of about 18.5psi when it should be hitting 20.1psi, and by redline it's down to 13-14psi instead of the 16 it should be at. the car is still on stock tune, the only mods are an HKS catback and K&N filter.

i know the obvious thing would be to check for a boost leak, which i plan on doing again. i just fixed a massive boost leak that i ran with for 2 years and didn't know i had, but now the boost seems lower than before i fixed it. i'm just wondering what else could cause the car to not build boost correctly. what are other things to look for besides the boost leak?

thanks in advance.

 

Vacume leak?

 

how would i check that?

 

sounds like a boost leak to me!

 

Subscribing.
I have the same issue. I have a stock Evo 9 MR and I hit around 17.5 max PSI. I thought some of the newer 9s the boost was turned down from the factory? I'd like to do a boost leak test too but unsure how. I will be installing a MBC soon though

 

I would do a hard look for boost leak(s). That's what it sounds like to me. GL with the fix!

 

Type in "Boost leak tester" in the search feature, there is your answers.

 

I had a similar problem due to a vacuume leak on the wastegate.

I was only running waste gate pressure, and as soon as it hit that pressure it would over power the spring and regulate my boost, at 15+- lbs (can't remember) it sounded like a monster because the waste gate was open, and dumping half my boost down the down pipe but I obviously was not hitting full boost, and slow.

There are two lines off the waste gate, at least on my car, and one of the hoses had dry rotted leaving a vacume leak to the boost controller. There are two things that can happen with this situation, depending on shich like leaks. One is that you'll run infinity boost which can cause LOT'S of damage, or two is you'll run the preassure of the spring in the waste gate, and all of the extra boost get's blown off it dosen't hurt anything but you don't have full boost.( kinda like a boost leak but not really a boost leak is more constant ) but with a wastgate vacuume leak it'll be fine boosting until you over power the spring.

I'm not sure what the stock wastegate/ or your wastegate spring is set at but it seems like you are having a similar issue to mine. My waste gate sits right up front on the left side, and the hoses get hot obviously because it's kinda close to the exhaust manifold.

Give that a look if you have already done a boost leak check. Let us know. My only experiences with my boost leaking have only been with blown off IC, Piping on more than one occasion due to hitting High boost 30+

 

thanks for the post. i will check that today. i'm running the stock BOV/wastegate, but my car's got 131k miles on it now, so the hoses and/or the BOV itself could be worn. the only place i think i could have a leak is the throttle body shaft seals, but even then i'm not sure.

i was also wondering if my ignition system isn't running at 100%, if that would affect boost levels? i remember when i changed the plug wires and plugs, the car started boosting better. i never did replace the coils though, and on cylinder 4 i get a missfire code. also, at high rpms in 5th gear, it feels like the car is missing a bit, and i'm planning to replace the coils soon, so i think that may help.

i'm just trying to find ALL possible causes of the low boost situation so once i start trouble shooting i'll know where to look. thanks for all the help, please keep the suggestions coming.

 

i would say do a boost leak test again.. it seems to hapen alot. i had 3 boost leaks one after another in like a 5 month span. it just happens i guess

 

He's asking for all possible reasons why his evo would not reach full boost!! Read what the OP wrote he's looking for other things bescides a boost leak!

What about the Turbo that is alot of mileage, I'm not too familiar with how they react when they start to go but that could be a worst case issue.

I'm not too sure that the plugs will stop you from boosting per say but they will improve the ignition of your Air/Fuel thus producing a cleaner burn, and cleaner power to spin the turbo. So I guess that would improve our over all power but unless your blowing out your spark, I can't see how that would affect your peak boost preassure.

 

thanks for understanding the intent of the post. i'd like to know what OTHER causes there could be for the car not reaching peak boost besides a leak. i was thinking about the turbo just being old too. I'm kind of in uncharted territory with the stock IX turbo as far as the miles go. being a pioneer sucks. i really hope that it's not the turbo.

anybody got a low mileage stock IX turbo for sale? ha

 

Is the turbo burning oil. Check for shaft play.

 

yeah Oil is a sure sign. lol

 

if you have acess to a smoke machine plug it in the intake or any line really and look for smoke easiest way to find the leak plug it in and sit back