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

[400whptsi]

thanks i will do a leak test thanks for the info

 

[400whptsi]

hi ive recently posted a couple of threads and the feed back from them were very helpful but i still am having problems i did a blt and fixed all my leaks and still the car is over boosting only in second gear and up 1st gear everything works great and ut takes off like a bat out of hell but after that big power loss and it over boosts i have it set at stock psi but it will creep to the max and hit fuel cut off ive tryed everything but porting the wastegate and im trying to avoid that if i can ive worked on cars my entire life i built a 500+whp dakota r/t but this is my first turbo car and i cant figure it out and getting frustrated can you guys help thank you

 

[JusMX141]

You need to port the wastegate hole, upgrade the flapper, and/or add some restriction to your exhaust.

There are at least 1,000 threads on this topic.

 

[Calan]

I can't even read that...my head hurts.

But after following Justin's advice ^^^ and reading the threads he mentioned, you may also want to search for "peepers mod".

 

[JusMX141]

Nothing cures creep like adding backpressure. Even Peepers had creep issues with one of his own modded actuators when running a very low-restriction exhaust on his 14B-powered 1G.

 

[400whptsi]

so my 3in exhaust is some of the problem then i take it. i have a cat on it.
whats a good way to add back pressure?

 

[JusMX141]

Smaller / stock downpipe would be the best way.

You're not really "using" a 3" exhaust if you're only at stock boost. The exhaust is overkill and is causing problems like boost creep.

 

[wowzers]

So you guys are telling me I got a 14b on 16-18 PSI in different gears if I get a 3" downpipe + catback im gonna boost creep till fuel cut?

 

[JusMX141]

There's a big difference between attempting to run 10psi and 18psi. The O.P. is having issues running very low boost, but may have no problem if he were attempting to run 18psi.

 

[NOSLO2PT0]

So you guys are telling me I got a 14b on 16-18 PSI in different gears if I get a 3" downpipe + catback im gonna boost creep till fuel cut?

Yup, or until you hurt the motor. I've got a guys car here that had a full 3" turbo back on basically a stock car. I ported out the wastegate but didn't help much. Motor is getting rebuilt as we speak, as he cracked a ringland in #1 and melted a hole in #4 pistons. Can't run 20+psi on a bone stock car and 93 octane without some sort of tuning device/logger.

 

[400whptsi]

you are making no sense to me the car i have is built for the boost from the bottom up the car ran fine at 11psi for a month for break in and i have not messed with anything and now all a sudden its boost creeping so its put together right it just started doing this and i think it is because the nipple going into the j pipe is leaking and the waste gate isnt working right sound like the problem i havnt fixed it yet so i dont know ive been busy

 

[wowzers]

Try running my boost levels 16-18 PSI it mostly spikes to 18 then holds at 16 1/2 my only mods are Hard IC pipes 2'5" Ported Manifold MBC 1gen BOV walley 190lph fuel pump No tuneing no injectors my plugs come out looking a nice crispy brown =) works for me try cranking up the boost

 

[400whptsi]

my fuel system is only set up for 14-15psi max

 

[wowzers]

I have a stock fuel system too.....All I got is a 190 lph pump and Im running 16-18 fine

 

[DSMDriver69]

I have a stock fuel system too.....All I got is a 190 lph pump and Im running 16-18 fine

Your fuel system is not really stock if your running a 190 pump

 

[thatblondechik]

Fuel has nothing to do with boost creep. I don't even know why that was brought up.

Think of how a wastegate works...you have it set for say 11psi. When your BC source "sees" that you've reached your 11psi, it opens the wastegate. If the hole that the exhaust gasses exit out of is too small, exhaust gasses can't exit quickly enough to maintain 11psi...causing your boost creep.

If you were to say, up the boost to 15-18psi, you would see less (if any at all) creep because the wastegate isn't having to divert as much flow for such a low pressure setting.

Make sense? Port the wastegate or up the boost. Or even better...do both.

 

[400whptsi]

yes that does so i fix my j pipe leak and turn the boost up to 15psi or more i sould be ok

 

[thatblondechik]

Now just for the record, I'm not telling you to just crank the boost way up. But you'll be fine on 15psi. But hey...if you're down there anyways, why not toss that 14b and slap on a nice b16g?

 

[JusMX141]

Fuel has nothing to do with boost creep. I don't even know why that was brought up.

I guess in reference to "having enough fuel to run over 15psi". I'm not sure why it was really brought up either....if the O.P. wanted to run 18psi, he'd be there.

Think of how a wastegate works...you have it set for say 11psi. When your BC source "sees" that you've reached your 11psi, it opens the wastegate. If the hole that the exhaust gasses exit out of is too small, exhaust gasses can't exit quickly enough to maintain 11psi...causing your boost creep.

You are exactly right....however, keep in mind the stock wastegate system generally works flawlessly at stockish boost levels (10-12psi) with the full stock exhaust in place. It's not until someone replaces the stock exhaust with an overkill 3" system that we see the term "boost creep" popping up. Here's why:

The larger exhaust system flows too freely, and the TD05H turbine wheel itself doesn't offer much backpressure at such a low boost level. When you take away all of the post-turbine restriction, the exhaust flow entering the turbine housing would rather continue to pass though the housing instead of escaping through the wastegate hole. This continues to spool the turbo more and more instead of diverting the airflow past the turbine wheel and through the wastegate hole.

If you were to say, up the boost to 15-18psi, you would see less (if any at all) creep because the wastegate isn't having to divert as much flow for such a low pressure setting.

...and there would be more turbine backpressure at a higher boost level anyway, so the chance that the exhaust flow would rather escape through the wastegate hole is much greater the higher the boost level is.

 

[thatblondechik]

Only when I try to help a little, do you elaborate where you'd usually have some short, snide remark. Always gotta 1up me...

But yes, OP. Listen to the know-it-all...he's actually very knowledgeable.

 

[wowzers]

So if he could be good with just settin the boost up to 15 psi and his boost creep would almost disappear? If so whats so hard about doing that 400whp? It would have already been done if it was me

 

[jrohner]

I would definitely get the supporting mods to run higher boost and not even care about boost creep. Once you get to 20psi or so, you'll wonder how you could stand running anything less.

 

[400whptsi]

thank you guys for all your help im fixing the problem now and then i will turn the boost up to 14-15psi and hopfully she will run like a raped ape because the engine is modded for it i just had it down for break in it just had the work done and i ran her good for 1500mi its time to let her loose hopefully thid nipple on the j-pipe is the problem

i have the supporting mods other than the injectors and the fuel pump motor is built it can probably hold 30psi maybe more i was going to get the evo 560cc injectors and the walbro 255

 

[Garman112]

i had just picked this 1g up and dont really know to much about it i was told it has a 16g n i know 16g are notorious for boost creep unported... the car is running 10lbs. when under boostand i leave off the gass the boost gauge jumps to about 15-17lbs is that boost creep or do i have other problems

 

[dsmdeliveryboy]

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?