Combatting boost creep.. (GT2871R)

[opponheimer]

Running 17lbs on 740cc's with a gt2871r 0.64 turbine housing, and I'm getting the usual expected boost creep at top end of higher gears..

Would a larger diameter external gate be my only option to combat the creep? It's creeping past the 20psi mark on my boost gauge. AFRS are 11.4:1

Oh and my actuator is fed off a hot pipe pressure source.

Any ideas would be appreciated.

[KA-T_240]

What else do you have on your setup?

What kind of wastegate, manifold, exhaust...... It sounds like you have an internal WG. Try porting your manifold so more air gets into and out of the WG. or switching to a divorced dump setup and have a open dump WG(its loud, but I love it!)

[mayco_86]

Divorce chamber dump will help take some boost creep away. The best thing to do is to get an external WG. I had the same problem and when I switched to External everything was good. Also have you dynoed your car. If so what kind of numbers did you make.

[garagelu]

What boost controller are you running?

[serturbo]

I'm with garagelu and KA-T_240. What's your setup like? A number of things could be causing your problem.

[KA-T_240]

a good boost controller can also help the situation.

I guess I dont know what options there are for bottom mount guys(based on turbo, I am assuming) that have external wastegate.

[opponheimer]

boost controller doesn't matter. boost creep is caused by a wastegate opening that is too small.. I'm running adjustable actuator rod.. Changing a boost controller won't do shit... think about it. Also me telling you my setup won't accomplish shit either, intake front mount, exhaust, greddy o2 housing is what i have, same as almost everyone else.

Has anyone here successfully ported their stock turbine housing wastegate? I've heard of people using giant washers welded to the flapper..

[louisdaboois]

it could possibly be a boost controller. if it's manual. honestly, trying to adjust boost with a mbc, it could leak when getting into higher amounts of boost causing the acuator to see less and less pressure in turn causing boost creep. but since your running an adjustable rod, thats not your problem... obviously. other than that, a divorced chamber dump tube with the wg dumped to atm like ka-t 240 said, should help out alot. I have a friend running an internally gated 60-1 @ 25psi and only creeps a couple psi at the top end of 3rd. for the most part it stays steady.

[serturbo]

Originally Posted by opponheimer

Changing a boost controller won't do shit... think about it. Also me telling you my setup won't accomplish shit either, intake front mount, exhaust, greddy o2 housing is what i have, same as almost everyone else.

Don't be an a$$. People here ARE trying to help you. I can see being a little irritated if there were unreasonable suggestions like a blown fuse or something.

[opponheimer]

Originally Posted by serturbo

Don't be an a$$. People here ARE trying to help you. I can see being a little irritated if there were unreasonable suggestions like a blown fuse or something.

What is boost creep? (from turbobygarrett.com)
Boost creep is a condition of rising boost levels past what the predetermined level has been set at. Boost creep is caused by a fully opened Wastegates not being able to flow enough exhaust to bypass the housing via the Wastegates itself. For example, if your boost is set to 12psi, and you go into full boost, you will see a quick rise to 12 or 13psi, but as the rpm's increase, the boost levels also increase beyond what the boost controller or stock settings were. Boost creep is typically more pronounced at higher rpm's since there is more exhaust flow present for the Wastegates to bypass.
Effective methods of avoiding or eliminating boost creep include porting the internal Wastegates opening to allow more airflow out of the turbine, or to use an external Wastegates.


Sorry I didn't think you guys knew what boost creep actually was..

[murda-c]

it's not like anyone was trying to eliminate problems with your boost controller or wastegate actuator...

if you already know how to fix the problem, why ask?

[opponheimer]

Was curious to see what alternate ways there were to eliminate boost creep, and what people with the same problem have done in the past. I'm curious if the aem trueboost boost gauge/controller would help..

Something that drops the pressure needed to spring the actuator rod as boost starts to creep may help greatly....

If i run 12lbs it creeps to 14..
if i run 15lbs it creeps to 17..
17lbs creeps to 21 some.. <-- thats where i'm at now in the s14

[serturbo]

I knew what it was. Hence, my question about your setup. A restrictive exhaust could cause it.

While searching the internet, I saw a bolt-on revised turbine outlet with new flapper valve. IIRC, it boasted about improved flow. I tried searching again, but couldn't find it. I'll keep looking and post it for you if I find it. It could be a better alternative than trying to port it out.

[codyace]

There is a thread on F/A dealing with this...not sure if you are in it or not, but it's basically down to adding an external gate.

Porting work (like the one member did), but I would NOT want to take it out, port it, put it all back together, only to have the same issue again...

[opponheimer]

Originally Posted by codyace

There is a thread on F/A dealing with this...not sure if you are in it or not, but it's basically down to adding an external gate.

Porting work (like the one member did), but I would NOT want to take it out, port it, put it all back together, only to have the same issue again...

You run external gate dont you?

Would you recommend larger than 38mm? Also, what are your opinions on dual wastegate internal and external?

[statik]

Originally Posted by opponheimer

boost controller doesn't matter. boost creep is caused by a wastegate opening that is too small.. I'm running adjustable actuator rod.. Changing a boost controller won't do shit... think about it.

Originally Posted by opponheimer

I'm curious if the aem trueboost boost gauge/controller would help..

I dunno opponheimer, according to opponheimer a boost controller won't help you

on a serious note

Originally Posted by opponheimer

Something that drops the pressure needed to spring the actuator rod as boost starts to creep may help greatly....

that's basically why everyone mentioned it in the first place, a properly setup boost controller can help with boost creep in some situations

[opponheimer]

Originally Posted by statik

I dunno opponheimer, according to opponheimer a boost controller won't help you

on a serious note



that's basically why everyone mentioned it in the first place, a properly setup boost controller can help with boost creep in some situations

Lol, that was my uhm, brother, no, just arguing with myself.

[KA-T_240]

Trust me, I know fully what boost creep is. I had a 8psi spring on my setup. First time i went to go drive, I saw 28psi. You know how if got it somewhat under control???????? a BOOST CONTROLLER. Boost Creep can also be cause by not getting proper flow to the WG, like a improperly designed WG runner, improper recirculation pipe into the exhaust angle....................

Your setup DOES matter. Not the intercooler, BOV...... What does matter when boost creep is involved is your Manifold, WG, WG style, Turbo, Exhaust. for instance if you where running a gt55R@50psi, a 38mm wastegate will not work

You do not need anything bigger then a 38mm for your tiny turbo. Also dont assume everyone has a setup like yours. I don't never did, never well. You can't run dual WG on a internal WG. You dont need Dual WG unless you have a twin scroll turbo, or if you are running something like a GT40+. My friends GT47 supra has boost creep with a 60mm WG.

I tried to help, you became an ass, I am done helping with this topic.

[opponheimer]

Originally Posted by KA-T_240

Trust me, I know fully what boost creep is. I had a 8psi spring on my setup. First time i went to go drive, I saw 28psi. You know how if got it somewhat under control???????? a BOOST CONTROLLER. Boost Creep can also be cause by not getting proper flow to the WG, like a improperly designed WG runner, improper recirculation pipe into the exhaust angle....................

Your setup DOES matter. Not the intercooler, BOV...... What does matter when boost creep is involved is your Manifold, WG, WG style, Turbo, Exhaust. for instance if you where running a gt55R@50psi, a 38mm wastegate will not work

You do not need anything bigger then a 38mm for your tiny turbo. Also dont assume everyone has a setup like yours. I don't never did, never well. You can't run dual WG on a internal WG. You dont need Dual WG unless you have a twin scroll turbo, or if you are running something like a GT40+. My friends GT47 supra has boost creep with a 60mm WG.

I tried to help, you became an ass, I am done helping with this topic.

sorry champ................

[McRussellPants]

Some guy on Fresh alloy fixed his creep with an intake


probably got some sort of dumb issue.


2871 shouldn't be creeping.

[garagelu]

Originally Posted by opponheimer

You run external gate dont you?

Would you recommend larger than 38mm? Also, what are your opinions on dual wastegate internal and external?

no, cody runs a internal wastegate just like every other 2871r owner out there. There may be a handful that run external but I guarantee you, 80-90 percent of the 2871r user are just running the stock internal wastegate. The whole point in running a 2871r is so you can get a nice stock setup without having to modify and spend too much money.

Now you say that the boost controller has nothing to do with this problem. I dont understand why you would say that. Isnt the line from the actuator run to the boost controller? If you have a crappy boost controller or dont have it set up right, I know from experience it could could boost fluctuation and creep. I run the HKS EVC 5 boost controller and I have no problems and no complaints with my 2871r.

And then I also can bet on that if you take the boost controller off and just run the wastegate pressure, it will hit 14lbs perfectly. 2871r uses a 1 bar spring. This should tell you if its the boost controller or not.

[Paul2x]

Get a different turbo.

I had the exact same issues, but worse... boost would climb to 1.8 + if we kept our foot in it.. More boost w/ more rpm. no way controlling it what so ever.

We tired everthing in the book.

-Removed Boost controller (less variables)
-tapped different boost soruces. (To see if acuator would open at different times)
-Switched to HKS acuator. (no better) , adjusted length to look at stroke and movement.
-Removed Acuator completely and saftey wired waste gate door open: No Change!
-Pulled Turbo, ported wastegate port and surrounding area. A little better. but sill 1.7-1.8 bar..
-Pulled turbo again, more porting, flange and turbo flange. Mildly better.
This was all with the wastegate port WIRED wide open the whole time.

Ended up just pulling the dam thing.

-Stock turbo back on , held 1.0 bar all the way to redline.

My guess is givien the right cam' set up and few other supporting mods, the Garette with a internal gate's design is just crappy and can't flow the amount of air need to controll boost. Everyone that worked on the car han Never seen anything like this. Would it have happened with the HKS version (GTRS)? I guess i'll just have to drop 2k and find out....lol

Good luck

[serturbo]

Are you sure it's boost creep? I'm thinking it's just the slow response of an internal wastegate. Even an external is pretty unresponsive by itself. I'd suggest getting an electronic boost controller (set that to 17 psi)and setting your actuator to stock.

It's not like a wastegate set at 9 psi will cause the turbo to slam into 9 psi and stop. It'll probably hit 6 or 7 pretty quick and then maybe max out at 7.5 or 8. It's just the inherent design of a wastegate. It bypasses more and more exhaust as turbo pressure builds.

[opponheimer]

Originally Posted by Paul2x

Get a different turbo.

I had the exact same issues, but worse... boost would climb to 1.8 + if we kept our foot in it.. More boost w/ more rpm. no way controlling it what so ever.

We tired everthing in the book.

-Removed Boost controller (less variables)
-tapped different boost soruces. (To see if acuator would open at different times)
-Switched to HKS acuator. (no better) , adjusted length to look at stroke and movement.
-Removed Acuator completely and saftey wired waste gate door open: No Change!
-Pulled Turbo, ported wastegate port and surrounding area. A little better. but sill 1.7-1.8 bar..
-Pulled turbo again, more porting, flange and turbo flange. Mildly better.
This was all with the wastegate port WIRED wide open the whole time.

Ended up just pulling the dam thing.

-Stock turbo back on , held 1.0 bar all the way to redline.

My guess is givien the right cam' set up and few other supporting mods, the Garette with a internal gate's design is just crappy and can't flow the amount of air need to controll boost. Everyone that worked on the car han Never seen anything like this. Would it have happened with the HKS version (GTRS)? I guess i'll just have to drop 2k and find out....lol

Good luck

Thank you,

[McRussellPants]

I've never seen a 2871 not hold within 3lbs on on an internal gate.

cams or otherwise.

theres something wrong with your setups.

figure out what it is.

Trading a 2871 for a GTRS would be about as retarded as I'd expect from zilvia but damn luddy.

when half the 240sx community does it just fine, and your shit fucks it up don't you think you would try and find the problem with your car?

god knows you ricers are just looking for an excuse to add a tial to your mods list.

[usdm180sx]

Originally Posted by Paul2x

Would it have happened with the HKS version (GTRS)? I guess i'll just have to drop 2k and find out....lol

Good luck

Yes it would! On my s14 with the GT-RS I had boost creep so I was limited to 1.15 bar using the Blitz i-color sbc boost controller. It was rock solid stable at that level but anything higher saw boost going to the moon. GT-RS is the same turbo as the 2871r .64.

I was gonna try a greddy elbow which i had before the turbo upgrade. G-dimension pushed a megan elbow on me; they said the greddy elbow wouldn't "fit" which is complete bs, all that's needed is to trim the divider plate but I sold the car before I could try it. Jon at HKS suggested the YF turbo elbow.

[tacotacotaco]

Just from hanging out with the engineers from roadrace which most of them happen to have sr'd s chassis whenever they built an sr for someone in their group any internal wastegate turbo they would weld the flange shut and weld an external wastegate flange to the manifold. Only efficient way to stop boost creep on gt28 series turbos. One of the motors had an hks turbo 2835 same deal until they just did an external wastegate.

[jspaeth]

"god knows you ricers are just looking for an excuse to add a tial to your mods list."


hhhahahahahah

[codyace]

Originally Posted by McRussellPants

Some guy on Fresh alloy fixed his creep with an intake

It still creeped a tad for Def. Main reason for intake change was due to lack HP found.

Originally Posted by McRussellPants

2871 shouldn't be creeping.

They certainly do though...

Originally Posted by McRussellPants

I've never seen a 2871 not hold within 3lbs on on an internal gate.

I had mine adjusted with no preload. Holds 12, then 14, then 16 then 20....

Originally Posted by McRussellPants

theres something wrong with your setups.

Did it when new, does it now. Changed some things around, same issue.

I'm going to try a new vacuum line once more (this time, using the fabricy coated vacuum line type, and go from three. I'm certain it won't solve anything though.

Originally Posted by McRussellPants

god knows you ricers are just looking for an excuse to add a tial to your mods list.

Exactly why I'm putting it on my stocker. I wish I could control 20 psi during HPDE on street tires. I wish I could afford 800 bucks in tires to run higher boost and not worry.

[rps13drift]

Solution to boost creep. Weld internal flapper shut and just run a tial 38! You will even pick up a few hp's!