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

[DJYoshaBYD]

http://www.geocities.com/chmwatson/FAQs/mbc.html

towards the bottom of this page, I think step 8, there is a diagram of how it works and how it gets hooked up.... hope this helps a bit

 

[Kindawg]

I recently put a EVO3 Big16g , SBR exhaust manifold, Apexi 3' Turboback exhaust,, SSAC FMIC on my car. I was not able to put my fuel mods in yet because i didnt have much time. When I put my turbo and FMIC on i drilled a hole in a coupler and I gorilla glued and rtv'ed a nipple on it so my MBC would go there.

When Im about 1/2 throttle i can hit around 10psi but if I give it full throttle the boost raises to 15 and then to 21psi causing me to have fuel cut because i dont have my fuel mods in. I have the MBC turned all the way off and Im stil hitting 20psi, Would this be considered boost creep? Im still running on my stock 02housing. Im kinda new to the whole dsm scene and If anyone could help I would much appreciate it.

 

[coreyr]

yes thats boost creep, Evo 3's are notorious for that. supposedlyyou can port the turbine housing where the wastegate hole is to get it to try to force the exhaust through the wastegate hole/flapper but ive never seen it work in person. MHI designed the watsgate so horribly the flapper opens less than 45* so how much exhaust can you get out of a 34mm hole thats half blocked by the flapper?

 

[Zack Huffman]

^^He's right about the E3 and mitsu's desgin of the WG. I would try porting the turbine housing and WG side of the O2 housing first though, since it is your least expensive option. If you can't resolve the problem that way, you're probably going to have to buy an external WG.

 

[kenamond]

If you plan on doing the fuel mods and SAFC, DSMlink, etc. in the near future (you just said you didn't have the time, so does this mean you have all the parts?), then you may try the 3rd option for e3b16g creep (other than porting or external wg) which is to get supporting mods and run 21psi. The porting will either cost you or will take a fair amount of time (I ported my FPB28, ex mani, O2 housing - fun stuff, but not a 15 minute job either). The external gate isn't cheap and requires a ex. mani mod or new mani.

The external gate will probably fix it, but some folks still have creep problems even after porting, because you still have the lame WGA flapper issue.

It's up to you, but if you're ready for the fuel mods, that's probably the cheapest solution - and you'll be at 21psi boost!

Porting the turbine housing might be something you want to do anyway to improve flow (decrease pressure losses pre-turbine).

If you can wait for a bit to get the fuel mods done, just lay off the gas pedal - and make sure your MBC is not wired to your IM (sounds like it's on an IC pipe, so that'd be okay) or you won't be able to limit boost with your foot as easily (may still creep at half-throttle, for example).

 

[DSMunknown]

http://www.allpar.com/mopar/boost-creep.html

 

[JayRolla]

If you plan on doing the fuel mods and SAFC, DSMlink, etc. in the near future (you just said you didn't have the time, so does this mean you have all the parts?), then you may try the 3rd option for e3b16g creep (other than porting or external wg) which is to get supporting mods and run 21psi. The porting will either cost you or will take a fair amount of time (I ported my FPB28, ex mani, O2 housing - fun stuff, but not a 15 minute job either). The external gate isn't cheap and requires a ex. mani mod or new mani.

The external gate will probably fix it, but some folks still have creep problems even after porting, because you still have the lame WGA flapper issue.

It's up to you, but if you're ready for the fuel mods, that's probably the cheapest solution - and you'll be at 21psi boost!

Porting the turbine housing might be something you want to do anyway to improve flow (decrease pressure losses pre-turbine).

If you can wait for a bit to get the fuel mods done, just lay off the gas pedal - and make sure your MBC is not wired to your IM (sounds like it's on an IC pipe, so that'd be okay) or you won't be able to limit boost with your foot as easily (may still creep at half-throttle, for example).

This is what i pretty much told him on dsmtalk.com, funny.

 

[MaxPSITalon]

Could the amount of vacuum line between the waste gate actuator and the fitting in the intake pipe cause this? How much line do you have? Also, how about a boost leak?

 

[John_GST]

If you plan on doing the fuel mods and SAFC, DSMlink, etc. in the near future (you just said you didn't have the time, so does this mean you have all the parts?), then you may try the 3rd option for e3b16g creep (other than porting or external wg) which is to get supporting mods and run 21psi. The porting will either cost you or will take a fair amount of time (I ported my FPB28, ex mani, O2 housing - fun stuff, but not a 15 minute job either). The external gate isn't cheap and requires a ex. mani mod or new mani.

The external gate will probably fix it, but some folks still have creep problems even after porting, because you still have the lame WGA flapper issue.

It's up to you, but if you're ready for the fuel mods, that's probably the cheapest solution - and you'll be at 21psi boost!

Porting the turbine housing might be something you want to do anyway to improve flow (decrease pressure losses pre-turbine).

If you can wait for a bit to get the fuel mods done, just lay off the gas pedal - and make sure your MBC is not wired to your IM (sounds like it's on an IC pipe, so that'd be okay) or you won't be able to limit boost with your foot as easily (may still creep at half-throttle, for example).

I agree with this, if you have time try to get your fuel mods on and run 21 psi, but i would still consider the ex. waste gate. i have the 16g also and as soon as i get enough money to go external i deffinately am. good luck.

 

[red_devil]

Im having the same problem with my car. Ony started to have creep after I put my 3" dp and no cat on. boost to 13psi then creeps to 20psi

I ported my turbo before I installed it, exhaust housing and near the flapper so it opens to a near 90 deg.

Is having the stock 2g o2 housing causing some of my creep?

Looking to run 580-650s in the future so I will running close to 20psi anyway, but I like having control of my boost.

 

[kenamond]

Im having the same problem with my car. Ony started to have creep after I put my 3" dp and no cat on. boost to 13psi then creeps to 20psi

I ported my turbo before I installed it, exhaust housing and near the flapper so it opens to a near 90 deg.

Is having the stock 2g o2 housing causing some of my creep?

Looking to run 580-650s in the future so I will running close to 20psi anyway, but I like having control of my boost.

It's quite common for folks to start seeing creep when they free up the exhaust. The turbine flows much more freely, and the wastegate can't keep up (can't divert enough exhaust around the turbine) and you start seeing creep.

The stock O2 housing isn't the problem. Going to a larger, aftermarket O2 will free up the exhaust even more. That's all good, by the way. The true problem is the wastegate flow (or lack of it). That porting you did to open the flapper 90* was a waste of time (no offense). The big problem is that the WGA only opens the flapper about 45* or so - it just doesn't have enough throw to turn it more. If it could, that would probably help a lot of e3b16g owners .

Some claim that a "good" port job can fix it, but it may depend on the car. I read up for a week or so on porting before doing mine. There's a good tech article in the turbo tech section on porting, and it links to other threads describing the process in detail. I wrote a few detailed posts myself about my porting job. Maybe you could take a look and see if you did as good of a job as folks say you need to.

So you're in the same boat as the other creep-sufferers. Either fix the wastegate flow or run 20psi.

 

[red_devil]

It's quite common for folks to start seeing creep when they free up the exhaust. The turbine flows much more freely, and the wastegate can't keep up (can't divert enough exhaust around the turbine) and you start seeing creep.

The stock O2 housing isn't the problem. Going to a larger, aftermarket O2 will free up the exhaust even more. That's all good, by the way. The true problem is the wastegate flow (or lack of it). That porting you did to open the flapper 90* was a waste of time (no offense). The big problem is that the WGA only opens the flapper about 45* or so - it just doesn't have enough throw to turn it more. If it could, that would probably help a lot of e3b16g owners .

Some claim that a "good" port job can fix it, but it may depend on the car. I read up for a week or so on porting before doing mine. There's a good tech article in the turbo tech section on porting, and it links to other threads describing the process in detail. I wrote a few detailed posts myself about my porting job. Maybe you could take a look and see if you did as good of a job as folks say you need to.

So you're in the same boat as the other creep-sufferers. Either fix the wastegate flow or run 20psi.

I used the write-up when I did my porting. I didnt want to port to much just because I dont like having a thin wall in the exhaust housing. I ported the lip out and opened up the area around the WG passage.

How much will an aftermarket o2 housing generally increase the creep? (running maybe ported EVO3, or ss unit)

 

[Empir3 X]

Ok, i have boost creep to 16 psi and im not sure why.. I do not have any leaks and i have a controller that is set at 14 psi.

1996 Eagle Talon Tsi Fwd
List of mods:
3" Turbo back exhaust
ported 14b (exhaust side)
intake
boost controller

Parts not put on:
walbro 255
adjustable fpr

Im thinking my creep is due to the 3" downpipe but im not sure (noobie). The turbo and wastegate are new. Any suggestions or ideas?

Thanks,
Alex

 

[DSMboostin15]

What kind of boost controller do you have: manual or electronic? And is your down pipe connected to the stock exhaust or do you have a 3" all the way back?

 

[tkelly27]

http://members.shaw.ca/costall/1000Q/answers-problems.htm#Myboostistoostrong

It's because of your exhaust or your MBC, or both combined depending on your definition of 3" exhuast (cat + muffler, no cat? no muffler? nothing at all?)

Try setting the MBC lower to see if you can get less boost creep. If so, that'll be a temporary fix until you can port the wastegate/O2 housing. I'd do both personally. It may fix it altogether too, but it won't be as much fun.

 

[Eastwood95]

Turning down the boost isn't going to help, that's just less boost your car is using, and more the wastegate has to get rid of.

Boost creep is common when slapping a 14b & TBE on a 2g. You need to port the crap out of the o2 housing concentrating on the wastegate and wastegate flapper area. I had the same problem and I tried everything to get rid of it, and nothing worked until I bought a bigger wastegate flapper. That stock flapper simply isnt big enough to vent the excess boost your not using.

If that doesn't work, you might have to get a bigger flapper (like I did). I bought a bigger flapper from Team Rip Engineering a few years ago and it hasn't creeped since.

 

[Echo5Zulu]

Turning down the boost isn't going to help, that's just less boost your car is using, and more the wastegate has to get rid of.

Boost creep is common when slapping a 14b & TBE on a 2g. You need to port the crap out of the o2 housing concentrating on the wastegate and wastegate flapper area. I had the same problem and I tried everything to get rid of it, and nothing worked until I bought a bigger wastegate flapper. That stock flapper simply isnt big enough to vent the excess boost your not using.

If that doesn't work, you might have to get a bigger flapper (like I did). I bought a bigger flapper from Team Rip Engineering a few years ago and it hasn't creeped since.

Quick question for you. When you did the larger flapper mod did you have to bore the hole larger for more air to flow through when it opens up? Im currently porting my 16g and I made sure that I cut the notch so the flapper can open all the way properly but I didnt upgrade to a larger flapper. Hopefully this is sufficient.

 

[Eastwood95]

http://www.dsmtuners.com/forums/showthread.php?t=186525

maybe this link will help.....let me know if you still have questions....

You can make the hole slightly bigger if keeping the stock flapper.
When you upgrade to a larger flapper, you can make the hole much bigger.

So yes, when I upgraded to a larger flapper, I made the "hole" bigger. That's the point, to let more air escape.....but you already knew that.

 

[Echo5Zulu]

http://www.dsmtuners.com/forums/showthread.php?t=186525

maybe this link will help.....let me know if you still have questions....

You can make the hole slightly bigger if keeping the stock flapper.
When you upgrade to a larger flapper, you can make the hole much bigger.

So yes, when I upgraded to a larger flapper, I made the "hole" bigger. That's the point, to let more air escape.....but you already knew that.

Yes thank you, Ive actually read that thread earlier but was just wondering about the hole as no one really mentioned that part. Were both talking about the hole that the flapper covers not just the part leading up to the hole, right? I see he hogged a bunch out leading to the wastegate hole. Do you think the way he hogged that out could introduce a lot of turbulance to the flow going into the exhuast turbine under normal operation? It looks that way to me. Maybe I'll just try it the way I have it and see if it creeps. One other thing is he is only running 15 psi and this turbo probably flows too much to run that low of boost so thats why he had to be so aggresive on his methods of removing excess boost?? What are your thoughts?

 

[Eastwood95]

How much boost are you trying to run? If you're on stock internals, I'm hoping not more than 8psi. In that case you would definitely need a larger flapper.

I was talking about the actual hole that the flapper covers.

As far as the turbulance, you make a good point. You're worried about the air being directed towards the flapper when you're not getting on it right? As long as your wastegate actuator is working properly, I don't see it being a huge problem. If you are concerned about it, dont make the angle towards the flapper so dramatic. I personally haven't heard of or experienced any drivability issues after that type of directional porting. Mine is ported in that nature, just not to that degree. When the flapper is closed, the air will take the path of least resistance, in this case the turbine housing....

 

[Empir3 X]

The exhaust i have is a full 3" back. 3" downpipe with no cat and 3" cat-back. The boost controller is a MBC. Right now im using the 1g O2 housing and im going to get my 2G ported out. After i get that done ill post results back. Thanks.

 

[tkelly27]

Turning the MBC down can have an effect. When you add boost the amount of gases trying to exit the engine goes up as the boost goes up. @ 8psi there is less exhaust for a given RPM than at 14psi. It becomes self feeding as the compressor spins faster, the turbine is spun faster and on and on until *kaboom!*. So if you set it lower (less total exhaust to vent) in the first place, you might be able to reduce boost creep, or at least get it so that it's happening later on in the rev range.

Another thing that can sometimes help in that situation is an extra muffler. Occasionally you're right on the edge of boost creeping conditions and popping some extra back pressure on the system can help. Don't go out and buy one, but if you've got one, slap it on and see what happens.

Eastwood is 100% right, it will require the waste gate and O2 housing to be ported, and potentially a larger flapper to be put on to be properly, and permanently fixed.

Also, empire, if you checked out the "how to cure boost creep" link...
"Ever since I purchased my Evo316g from Slowboy Racing I have been plagued with Boost Creep. Much of this could be blamed on my 3 inch free flowing exhaust, and the elimination of my cat." This whole thread could have been avoided

The gases are traveling incredibly fast, and are going from a transition from 4 into one, across a flange, then spun around in a reducing cone circle thing (turbine housing). There is already a ton of turbulence going on in there, the little bit extra that is added from the port job is not going to make that big of a difference, especially when it will allow you to keep your car from over boosting.

I've never heard anyone complain about a waste gate that was to big

 

[TURB0]

I just had my 650cc injectors and ported evo 3 16g installed the other day. Prior to the install my boost gauge was set at about 12psi. However after the install I am unable to control my boost. Immediately after leaving the shop I was hitting 20+ psi and would let off. I disconnected my mbc and ran stock boost...however my car still hits 20+psi at WOT. Is there anyway to test my wastegate to see if its opening? I didn't think my 16g would creep like this.

 

[red_devil]

I just had my 650cc injectors and ported evo 3 16g installed the other day. Prior to the install my boost gauge was set at about 12psi. However after the install I am unable to control my boost. Immediately after leaving the shop I was hitting 20+ psi and would let off. I disconnected my mbc and ran stock boost...however my car still hits 20+psi at WOT. Is there anyway to test my wastegate to see if its opening? I didn't think my 16g would creep like this.

Welcome to EVO creep

I see that you have a 2.5 turbo back do you have a cat? The evo creeps due to lack of room for the exhaust gas to escape the WG. You could try doing a port job that has helped some owners (not me though). You could try buying a larger flapper and doing some porting in the WG passage. But with your 650s you could just run at 20psi

 

[TURB0]

Yes its a 2.5" with a cat. My car 'supposedly' had its exhaust mani and o2 housing ported by the previous owned but ive never confirmed that. I think that I am going to order an o2 housing with a dump anyway. I would be fine with the creep, but it is hitting just about 25psi which is too much for pump gas. Is there anyway to test my wastegate just to make sure?