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Turbo Boost Creep Creeping T25 14B 16G [Merged]

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Yea i do have n aftermarket gauge... but yea i mean ive never seen nething like this could a vaccum leak cause this
 
No boost creep is when you build boost and it spikes to a higher boost than it should be at and tapers down, usually from exhaust that is too free flowing and the wastegate flapper not being big enough. Do you have an aftermarket boost gauge? Or are you relying on the stock one?

You just described boost spike. Boost creep is when (on the throttle) boost goes to a certain pressure, then increases as the RPMs increase. This is because the wastegate is unable to bypass the exhaust enough and forces the excess air to spin the turbine faster (increasing the amount of boost).

What the OP is describing doesn't really make any sense. When you let off the gas, the boost can't spike an extra 6 to 7 psi out of nowhere.

You probably have boost creep.

Edit: I may have read that wrong. You probably described boost creep correctly, but just not that clearly.
 
I would double check where the boost guage is installed and make sure its in the best spot. Also the guage could be on the fritz, what brand is it?
 
Here's what it sounds like to me, and I'm a quite logical person.
When the throttle plate closes, the turbine is still spinning and pushing boost into the intercooler piping, then the PSI spikes, causing high backpressure on the turbine, causing it to slow quickly,and gas to escape backwards. This is what the BOV is here to prevent. The BOV opens to let the turbo keep spooling while the throttle plate is closed. thus preventing that boost spike in the intercooler piping when the air is rerouted back to the intake. This is easier on the turbo obviously. So I need to know 2 things to help with the problem. I need to know that your BOV is in working order, and that your gauge is hooked up in the correct spot. (Howlong is the spike shown? ifit's say half a second, then your BOV is in good working order, but if it is for a few seconds or more, then there is a problem with it.)
 
The gauge is a glow shift which i have herd have problems... the bov does work the boost spike is about a half Second. i have a punisment fmic im goin to put in with in the next couple of weels along with an o2 dump full exhaust intake n a new greddy type rz bov... will me of that help with the issue if not ### do i have to buy or do
 
It sounds good to me man. It sounds like there is that boost ramp up to push open the BOV, and once it's open the pressure is released. I'd say don't worry about it, but it also sounds like your gauge is installed in a funky spot. who knows though.
 
Ok i just wanted to make sure i wasnt gunna cause ne real damage... where is the best spot to hook the boost gauge so if mine isnt there i can change it i plane on replacing all the vaccum lines
 
I am porting out my evo III 16g to fix my creep issue and noticed something,has anyone ever ported straight down through the divider between the wastegate passage and the exhaust wheel? I mean the wastegate opens and vents downward towards that divider anyway, and wouldn't the exhaust flow out of the turbine wheel act as a guide for the wastegate gasses since it would be blowing into its path of flow? I know the hahn super turbo's vent this way and have no issues with creep or disturbing the exhaust flow because of the wastegate gasses. I would like some feedback before I possibly make a bad decision on my only exhaust housing. And if it works maybe this will be the new way to fix boost creep with an internal gate along with porting the passage. Any help would be appreciated.
 
The turbo creeps because

1. Much freer flowing exhaust causing the turbine to be the least resistant path.
2. The opening for the wastegate outlet is not a direct inlet path.


Cutting out the divider will cause more turbulance for the turbo and will not help with your boost creep issues until you fix the inlet passage.
 
I know I still have to port the wastegate passage that needs to be done regardless,my question was if removing the divider would help. According to DEJON it does DEJON | Powerhouse note the part about the service they offer of removing the divider to help eliminate boost creep. I was just trying to find out if anyone here had actually tried it out or knows for a fact it will help not speculate.
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Here is the image of what I was talking about
 
open o2 dump will help
what kind of exhuast system do you have?
 
My stock VF39 has the wastegate channel open to the main exhaust channel. It still creeps, and this is with 2 stock cats and a 2.5" exhaust system. It is also a power robbing design. Bad way to fix the creep.
 
open o2 dump will help
what kind of exhuast system do you have?

I am running 3 inch megan racing downpipe to a apexi n1 exhaust,with a 3 inch test pipe.

Well I went ahead and made the decision to do it, I don't have numbers or proof whether it will or will not hurt performance. I was just setting out to see if I could eliminate my creep issue,and it worked great I am dead on 20psi now. It would creep to 27+ psi before, and it feels healthier than ever...granted I'm going by the old butt dyno LOL I will post up pics of it once I upload them. I just want to contribute my 2 cents and what I achieved. Maybe it will help someone else down the road.

showimage.php


 
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I don't have numbers or proof whether it will or will not hurt performance. I was just setting out to see if I could eliminate my creep issue,and it worked great I am dead on 20psi now. It would creep to 27+ psi before, and it feels healthier than ever..

That's interesting if not a bit counter-intuitive. The divide reduces exhaust gas turbulence as it exits the turbo, and it looks like you're running at least 7psi less boost, yet the car feels healthier than ever.

This modification may negatively affect performance if you ever increase the boost later on, but that's speculation. It looks like it helped with the creep issue, so that's mission accomplished as far as you're concerned. :thumb: However, I'm hesitant to recommend this technique to solve boost creep because of the permanent nature of the modification. Additionally, as mentioned, this may actually hurt performance as exhaust flow increases (potentially) in the future.

I'm a fan of running any given turbo when the car is sufficiently modified to handle the minimum boost the turbo will provide. In many cases you'll find with the evo3 16G, it's relatively high.
 
The 14b I put on my car back in 2004 had that "mod" and I didn't know and I put an o2 dump on and it was constantly open :)

Ended up switching turbine housings a few days later.
 
That's interesting if not a bit counter-intuitive. The divide reduces exhaust gas turbulence as it exits the turbo, and it looks like you're running at least 7psi less boost, yet the car feels healthier than ever.

This modification may negatively affect performance if you ever increase the boost later on, but that's speculation. It looks like it helped with the creep issue, so that's mission accomplished as far as you're concerned. :thumb: However, I'm hesitant to recommend this technique to solve boost creep because of the permanent nature of the modification. Additionally, as mentioned, this may actually hurt performance as exhaust flow increases (potentially) in the future.

I'm a fan of running any given turbo when the car is sufficiently modified to handle the minimum boost the turbo will provide. In many cases you'll find with the evo3 16G, it's relatively high.

I just took a chance on it I was just so tired of pulling my turbo and porting it only to put it back on and still have creep. I definitely agree with you about being 100% sure before you do it because it is permanent. And I don't really plan on running much higher boost with this turbo anyway, that's what the holset H1C sitting in my garage is for:sneaky:

i havent done it to mine yet, but i did cut the divider out of the 02 housing.

What kind of boost are you running on your setup? Did you notice any negative effects after removing the divider in tho o2 housing?
 
i have a E3 16G with a obx tubular manifold, megan recirculating o2, catless 3" dp, and 3" cat back, needless to say i have boost creep. i am trying to set it at 20psi but i keep creeping up to 23/24 psi before i let off around 5500 in 3rd gear. it is a little frustrating, i am wondering, if i put my 2g manifold and o2 back on and try porting the inlet to the wastegate a little more will it help control my creep or is it a lot of work for nothing. does anyone have any suggestions, other than going to an external gate setup, which i am thinking about, just don't want to spend the money as i am trying to switch to speed density and my money is going elsewhere... any suggestions would be appreciated, thanks
 
i have a E3 16G with a obx tubular manifold, megan recirculating o2, catless 3" dp, and 3" cat back, needless to say i have boost creep. i am trying to set it at 20psi but i keep creeping up to 23/24 psi before i let off around 5500 in 3rd gear. it is a little frustrating, i am wondering, if i put my 2g manifold and o2 back on and try porting the inlet to the wastegate a little more will it help control my creep or is it a lot of work for nothing. does anyone have any suggestions, other than going to an external gate setup, which i am thinking about, just don't want to spend the money as i am trying to switch to speed density and my money is going elsewhere... any suggestions would be appreciated, thanks

Try to put back on the stock downpipe. that helps me.:thumb:
 
Either you will have to port it as much as possible which may work or get an external WG. Or the option of putting back on the stock dp - helps with less airflow which will help control boost creep.

Or maybe a dump tube.
 
i was hoping to avoid putting the stock dp back on, especially since i have my wideband in my rear o2 spot, crap this sucks, hahaha. its almost tempting to ditch the 16g in favor of something else if i have to go to an external setup to control the boost.
 
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