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

[grantman10]

Also, i forgot to ask you guys how much you think my spool time will drop after i get the 3" catback. Right now i hot full boost (12psi) by about 3100 rpms in third. I would be very happy if it could get to around 2800.

How did your guys spool time decrease after the catback exhaust?

 

[kris_stewart10]

okay i was boosting at about 10 psi and then my bost would creep like hell to about 16 psi then i would let off PSHHHHH that great BOV noise and then i would shift and i wouldnt creep but only in first and second gear would i creep third fourth wouldnt and i would in fifth just watch your boost gauge it gets horrible sometimes and i love my 16g from ebay but i dont think that the real 16gs have boost creep that i know of but just watch your boost gauge that is why i love my 1g my boost gauge is right there in a convient spot on the tach so i do not have to lift my eyes off the tach or the speedo

but i mean i blew my engine at 17 psi just reved too high and KABOOM but thats my fault ( DAMN corvettes)

 

[grantman10]

okay i was boosting at about 10 psi and then my bost would creep like hell to about 16 psi then i would let off PSHHHHH that great BOV noise and then i would shift and i wouldnt creep but only in first and second gear would i creep third fourth wouldnt and i would in fifth just watch your boost gauge it gets horrible sometimes and i love my 16g from ebay but i dont think that the real 16gs have boost creep that i know of but just watch your boost gauge that is why i love my 1g my boost gauge is right there in a convient spot on the tach so i do not have to lift my eyes off the tach or the speedo

but i mean i blew my engine at 17 psi just reved too high and KABOOM but thats my fault ( DAMN corvettes)

Thanks for the info, but please try to use better punctuation. I didnt count one period or comma in that whole sentence.

 

[Pirrofab]

I may not have a 16g but a co-woker of mine does and during the chilly mornings it tends to creep pretty bad. Hes running on average 20-26 psi on his boost controller but has scene creep to 30psi. I still only use the mighty 14b on my car with a full exhaust and a ported factory o2 housing and on cold mornings I see a 3-4psi surge when boosting and when its around 80-90 outside it may only creep 1-2 psi if any at all. I have heard the only way to eliminate creep is to go external wasegate or port the internal flapper. Maybe you can run an external gate and actually have it dump back into the exhaust on the lower portion of the downpipe using larger piping? I'm not sure if that has been done or if its practical but it just came into my head. I'm not sure if its safe for whatever reason so please correct me if I'm wrong.

 

[kris_stewart10]

i am sorry. i am not used to using any punctuation. but yea i have seen my creep go to 30 but that was before i blew my engine i wasnt watching and my car started to sputter. and then once i seen it spin my boost gauge around i let off and then PSHHHHHH!!!!!!!! the loudest i have ever heard a BOV. i was like WTF???

 

[Spoolin98]

I have a real Evo III 16g and a tubular 02 housing. I ported the hell out of the wastegate and used the 34mm wastegate and still couldnt hold boost under 22-25psi in the high rpms. Then I cut the wastegate arm and made it adjustable, now I can hold boost solid at 12psi to redline.
Give it a try. If you cant take your wastegate arm off the flapper or put it on without shooting compressed air throught the wastegate then its not opening fully. I made mine adjustable and made it so I can put the arm on and off the flapper stud without any effort. Now it holds boost just fine.

 

[grantman10]

yea i have seen my creep go to 30 but that was before i blew my engine i wasnt watching and my car started to sputter. and then once i seen it spin my boost gauge around i let off and then PSHHHHHH!!!!!!!! the loudest i have ever heard a BOV.

First off, i wanted to say that this was one of the funniest things i have heard in a while. I just got the picture of a boost gauge needle spinning so hard that it rotated the gauge in the bezel, causing him to notice that it was overboosting.

Spoolin98 could you try to re-explain that idea again? I didnt understand how it would help, it couldent work right because if it opened enough to cure creep, then, when closed, the flapper wouldent have enough preload to build boost efficiently. Mr. Peepers mod adjusts the lenth of travel in the wastegate mod, not loosen a bolt so the wastegate opens further.

Does anyone else understand what im saying?

I may be completely wrong.

 

[JusMX141]

Did you port the wastegate hole out before installing the turbo?

eBay 16-Junks look like this from the factory:

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You want it to look like THIS is you plan on regulating boost with an internally-dumped wastegate:

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[99 gst spyder]

i have a ebay 16g too. after the installation, it ran fine without any spikes or creep other then boost leaks that made it spike 1-2 psi that's it...wastegate flapper hole was not ported. ran fine and hold stock boot at 10 psi all gear....leak cause mine to creep. my ebay turbo still running strong after dyno/tune and got good amount of number out of it too....before dyno/tune i up the boost to 14 psi and still hold boost pretty good without any creep or spike like i said, the wastegate hole was not ported, (i don't think it is).... ( i'm using tubular mani and stock o2 housing)

 

[grantman10]

Did you port the wastegate hole out before installing the turbo?

eBay 16-Junks look like this from the factory:

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You want it to look like THIS is you plan on regulating boost with an internally-dumped wastegate:

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Wow! did that wastegate open that far without modification? Because that is way farther than a MHI e316g. Or did you do a wastegate mod?

What kind of boost are you running jusmx? Is is steady?

 

[Spoolin98]

To the OP, im not sure where you got loosening a bolt from my explanation? When did I say anything about a bolt?

I said I cut the wastegate arm, put an extension in it so the the wastegate flapper could open fully. It was only opening to about 60* or so, so even though I ported everything it wasnt enough. Making the wastegate arm longer allowed it to open a full 90* and stop the boost creep.

Here is a diagram of what Im talking about.
http://www.gnttype.org/techarea/images/Adj_wastegate.JPG

 

[JusMX141]

The problem is by lengthening the arm you're taking the tension off the actuator. This will effectively hold less pressure on the wastegate flapper, allowing it to blow open sooner under certain boost levels.

The ONLY way to effectively lengthen the actuator arm to ensure the flapper opens fully is to do the Mr. Peepers mod (http://www.dsmtuners.com/forums/art...boost-creep-modified-wga-peepers-mod-how.html) which doubles the actuator's throw without putting flapper tension in jeopardy.

Trust me, you don't need the flapper to open 90* to control boost. With my buddy's Frank 5 20G, we couldn't keep the flapper SHUT over 20psi; even with the arm shortened so much that the flapper only opened 1/4", it was still blowing open (the o2 dump told the tale).

 

[grantman10]

Boostin i didn't mean bolt, i meant the threaded arm of the actuator, since you made it adjustable. jusmx141 and i are on the same page, do you know what were saying?

EDIT: ok boostin, i read the link and that adjustable wastegate arm is a pretty neat idea. So would loosening it one turn make it so the flapper will open more?

 

[Spoolin98]

The problem is by lengthening the arm you're taking the tension off the actuator. This will effectively hold less pressure on the wastegate flapper, allowing it to blow open sooner under certain boost levels.

The ONLY way to effectively lengthen the actuator arm to ensure the flapper opens fully is to do the Mr. Peepers mod (http://www.dsmtuners.com/forums/art...boost-creep-modified-wga-peepers-mod-how.html) which doubles the actuator's throw without putting flapper tension in jeopardy.

Trust me, you don't need the flapper to open 90* to control boost. With my buddy's Frank 5 20G, we couldn't keep the flapper SHUT over 20psi; even with the arm shortened so much that the flapper only opened 1/4", it was still blowing open (the o2 dump told the tale).

I understand what your saying, but needless to say what I did worked for me.

 

[Spoolin98]

Boostin i didn't mean bolt, i meant the threaded arm of the actuator, since you made it adjustable. jusmx141 and i are on the same page, do you know what were saying?

EDIT: ok boostin, i read the link and that adjustable wastegate arm is a pretty neat idea. So would loosening it one turn make it so the flapper will open more?

Yeah if you lengthen the arm one or two turns it will open the flapper more. From the previous pictures that someone postd here it looks like the ebay 16g already opens all the way. The Evo III doesnt open that far without porting behind the flapper so it can open all the way and making the arm adjustable.

I havent had any problems with the wastegate flapper blowing open so far, its working just fine.

 

[JusMX141]

From the previous pictures that someone postd here it looks like the ebay 16g already opens all the way.

Those were taken on my bench- the exhaust housing was removed from the turbo. It will open pretty far on it's own, but even if you set the tension so the arm barely holds the flapper shut, the travel still will not permit the arm to open fully.

 

[Spoolin98]

Those were taken on my bench- the exhaust housing was removed from the turbo. It will open pretty far on it's own, but even if you set the tension so the arm barely holds the flapper shut, the travel still will not permit the arm to open fully.

Gotcha, well I know when I had the wastegate off my EvoIII it wouldnt open that far. The wall behind the flapper prevented it from doing so.

 

[JusMX141]

Gotcha, well I know when I had the wastegate off my EvoIII it wouldnt open that far. The wall behind the flapper prevented it from doing so.

Regardless, your flapper will never open that far while it's attached to an actuator...unless you do the Peepers mod.

If everything is working in balance, you won't have boost creep. This means that your exhaust system is just restrictive enough that once the wastegate opens the airflow will take the path of least resistance bypassing the turbine wheel. If you have an exhaust system that flows too freely (3" or bigger while running low boost levels that wouldn't require such a large system, or even an open downpipe) then the exhaust is flowing freely enough THROUGH the turbine housing, so it doesn't want to take the path of least resistance to bypass the turbine housing once the wastegate opens.

Controlling boost through an internal wastegate is quite a puzzling matter. If you run LOW boost, you'll want a BIG wastegate opening to divert the airflow around the turbine housing so the turbo doesn't continue to spool. It seems with the higher boost level you run, the flapper will have more of a tendency to blow open; so for HIGH boost levels you'll want a SMALL wastegate opening in order to keep the airflow from trying to escape through the wastegate.

 

[Spoolin98]

Regardless, your flapper will never open that far while it's attached to an actuator...unless you do the Peepers mod.

If everything is working in balance, you won't have boost creep. This means that your exhaust system is just restrictive enough that once the wastegate opens the airflow will take the path of least resistance bypassing the turbine wheel. If you have an exhaust system that flows too freely (3" or bigger while running low boost levels that wouldn't require such a large system, or even an open downpipe) then the exhaust is flowing freely enough THROUGH the turbine housing, so it doesn't want to take the path of least resistance to bypass the turbine housing once the wastegate opens.

Controlling boost through an internal wastegate is quite a puzzling matter. If you run LOW boost, you'll want a BIG wastegate opening to divert the airflow around the turbine housing so the turbo doesn't continue to spool. It seems with the higher boost level you run, the flapper will have more of a tendency to blow open; so for HIGH boost levels you'll want a SMALL wastegate opening in order to keep the airflow from trying to escape through the wastegate.

Your preaching to the choir, I already knew all that.
All Im saying is that by cutting the wastegate arm and making it adjustable it allowed me to legnthened the arm. Which in turn allowed the wastegate flapper to open more. Once I did this I had no more creep and I hold boost solid at 20psi, and as low as 14psi solid. Before doing this I couldnt hold solid boost at any psi, although I never tried over 20psi.

Thats with 1mm oversized exhuast valves on a 1g head with port work, evoIII ported, evoIII manifold with the collector ported, SBR tubular 02, and 3" exhuast with no cat.

 

[misterskeetz]

I have searched and read up but I can't seem to get a definitive answer.

I have a 98 gsx and I want to get a 3" DP into 3" high flow cat with custom 3" exhaust piping to apexi n1/megan m-gt muffler. I plan on keeping the stock t25 turbo for a while. (until it burns out). I do not want ANY boost creep at all. Do I have ANYTHING to worry about? Some say I wont see any creep. Some say I can creep to 20psi. Can I please get a solid answer? Maybe a dsm wiseman w/ a 2g chime in on this?

 

[cavillac]

I have a 2G running open downpipe and I have no creep problems.. actually with the stock exhuast the car wouldnt make full boost after 4k rpms now it makes full boost all the way to redline

 

[r1991_4g63t]

I have a 2G running open downpipe and I have no creep problems.. actually with the stock exhuast the car wouldnt make full boost after 4k rpms now it makes full boost all the way to redline

not 100% positive but i think thats what boost creep is, it should drop a little bit but the creeping is keeping it steady

 

[Quickspool]

I have searched and read up but I can't seem to get a definitive answer.

I have a 98 gsx and I want to get a 3" DP into 3" high flow cat with custom 3" exhaust piping to apexi n1/megan m-gt muffler. I plan on keeping the stock t25 turbo for a while. (until it burns out). I do not want ANY boost creep at all. Do I have ANYTHING to worry about? Some say I wont see any creep. Some say I can creep to 20psi. Can I please get a solid answer? Maybe a dsm wiseman w/ a 2g chime in on this?

Don't worry, you're fine. I have done it to my car myself with the stock T-25 and everything stays perfect. I think ditching the burnt out exhaust sensor led to some idling problems that could STILL let me drive best kind (even months before this mod when I first bought it in May 2004), but besides that, nothing. de-cated my exhaust system. Ran a 3" Custom built exhaust + APEXi N1 Muffler = Sweet, sweet sound, especially at top speed, and I've seen flames shoot out too! (Just 1 or twice).

So keep your sensor (or replace the burnt one?) run 3" the whole way, and throw in a much needed Boost Gauge to kill some curiousity. You will lose some Torque compared to a 2.5" but I'm sure you'll get it back with some more throw on's. No worries.

 

[scoby41]

Similar concern, but i'm running a td05 20g... don't know if that'll make a difference?

 

[knochgoon24]

I have full 3" turbo back, but I do have a cat. I don't have creep at all with the T-25. I'm full 15psi boost around 2400RPM. It's almost too soon for my likes.