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

[TSITurbo95]

Port the wastegate flapper. Port the wastegate hole big enough, but still retain a lip so that the flapper will seal.

http://www.dsmtuners.com/forums/tur...turbo-wastgate-not-working.html#post153086233

 

[dsmjunky737]

I have been having boost Creep issues with my car for a while now. I have a 16g compressor, 3in full exhaust with no cat, larger o2 housing and downpipe. With no boost controller my pressure is steady 10psi and rises to 20 plus near red line. I have already heavily ported the waste gate passage as Isaw in another tech article and did help some. As before it went off my gauge. I don't know where to go from here and would like to fix this before it causes catastrophic failure..

 

[miguelmcv]

Any pics of the port job?.

Did you port the rounding areas where the flapper hits, The flapper will hit the walls on the housing and air gets harder to flow out, Also, a 3" down pipe is insane for the 16g, is this a big, small or evo3 turbo?.

I would suggest to get back to 2.5 down pipe to kill the boost creep.

 

[dsmjunky737]

I believe it is a 2.5in downpipe and into a 3.0in the rest the way back. Unfortunately I did not take any pictures when I ported it. I did port some around where the flapper hits the housing probably be could have done some more. I also hooked the waste gate actuator up to about 20psi of air and it moves only maybe 30 degrees from its closed position. Not sure if that has any affect on flow. As for which turbo I'm not not sure I thought it was a 14b until someone told me it's was the larger 16. I took his word for it because he had 8 dsms in his driveway

 

[boostkrazy26]

You might want to consider a high flow cat system. I had the same problem when I was building my turbo project car and the high flow cat system helped alot with the manual boost control to pretty much eliminate the creeping

 

[dsmjunky737]

I will definitely consider that. I would just get a universal cat and get it welded in. I have used couplers and clamps before and it leaks and looks awful. Need to learn how to weld asap

 

[boost97gst]

If im not mistaken, freeing up the exhaust causes more boost creep, not less. Its all in the wg porting. You dont have a leaky line going to the wg do you?
Small turbos have always had problems with creep. Port the hell out of it so it can open all the way and make sure the rod is adjusted properly and the diaphragm in the wg isnt leaking either. Also, you might swap out a boost controller and test a different one just to rule that out.

 

[dsmjunky737]

I don't know have any controller hooked up to it at the moment. I recently replaced all the vacuum lines so Ithink the lines are good iI have the waste gate actuator hooked up directly to a port on the intake manifold. I ported the passage way to the waste gate where it makes a turn heavily and there i not much more I can go there but I can do some more work around where the flapper hits. I noticed there is a lot of tension holding the flapper closed I had to use pliers to get the arm on and off. Is that normal

 

[Cdc1221]

Yes its normal. What do you mean? You didnt have a hose hooked to the wastegate actuator?

 

[dsmjunky737]

I was just asking if it is normal that it's a struggle to get the waste gate actuator arm on the pin for the flapper. And if that might affect the distance the flapper door can open. I tried this I took the actuator off the flapper so that it was free to open fully and a pull in 3rd to red line and the boost still crept from 10 to 15psi. Now with the waste gate actuator connected boost creeps from 10psi to over 20psi my gauge stops at 20psi. I was thinking it's a combination of a 3in full exhaust and the waste gate actuator only moving a minimal amount but I could be wrong

 

[NHerron]

The arm will only move a little bit like you said, something like 30degrees so there's nothing you can do about that. Good job testing all that stuff btw that really helps. And yes the preload is good to have otherwise the exhaust pressure alone will be enough to push open that flapper before target boost is achieved. That's the downside to porting the WG hole, that is, if you ever want to max out the 16g, you may have problems holding higher boost.

Before I removed my 3" high flow cat, I could hold stock boost all day long. And that was with absolutely no WG porting and a 3" downpipe. So my vote is to go with a high flow cat, it won't kill hardly any power but will help with your backpressure issue and hey, you'll even be saving the planet .

 

[dsmjunky737]

Thanks for the help I think I'll go with the high flow cat approach. Any ideas of where Ican get a reasonable one.

 

[hazmat6135]

I don't know have any controller hooked up to it at the moment. I recently replaced all the vacuum lines so Ithink the lines are good iI have the waste gate actuator hooked up directly to a port on the intake manifold. I ported the passage way to the waste gate where it makes a turn heavily and there i not much more I can go there but I can do some more work around where the flapper hits. I noticed there is a lot of tension holding the flapper closed I had to use pliers to get the arm on and off. Is that normal

I think this is a big part of your issue! Your BOV should be hooked to the manifold because the difference in pressure when you close the throttle is what opens it. A waistgate should open based on the pressure just past the turbo in the intercooler pipes. this is why the factory setup comes straight from the J-pipe. I would def try to change that first. The way you have it the waistgate will shut when your not at WOT so as you slightly let off the gas your boost will spike.

 

[NHerron]

Manifold and jpipe will be same psi give or take a couple psi due to IC pressure drop. I personally use the jpipe source as of recently but had it hooked to manifold for a while and it held boost just fine.

BTW, forgot to add I also had a tubular 02 housing with a 2.5" outlet.

 

[dsmjunky737]

I would prefer to use the j pipe source for my bov but the aftermarket j pipe I have on it does not have a port to attach the bov line to.

My bad meant to say I'd rather have the waste gate actuator hooked to the j pipe

 

[hazmat6135]

Take it to a exhaust shop and havem weld a bung on.Shouldn't cost much at all. Nherron they are the same when your at wide open throttle. Any other time when the throttleplate is slightly closed the restriction causes a pressure drop in the manifold from whats in the pipes. That difference is what makes a BOV open. If your waist gate is hooked there it will read the lower pressure and close which will cause a boost spike. Get how it works?

 

[NHerron]

Take it to a exhaust shop and havem weld a bung on.Shouldn't cost much at all.

Good luck finding a shop that can weld thin aluminum especially even finding a 1/8 bung. Not impossible but would be a lot easier if it were steel.

Nherron they are the same when your at wide open throttle.

No, no they are not. I'm on a tablet so I'll keep it short (damn pos laptop). An intercooler will have a pressure drop, cheap units will not be tested for this drop at different levels of airflows but better brands will test and list it.

Any other time when the throttleplate is slightly closed the restriction causes a pressure drop in the manifold from whats in the pipes.

For a split second it might be a restriction but pressure will equalize and no longer be a restriction for that current airflow. Remember the turbo slows down due to less exhaust pressure, compressor output is proportional to turbine inlet pressure.

That difference is what makes a BOV open.

If adjusted correctly a bov is only going to open with throttle all the way closed (pressure still in pipes assuming). Otherwise bov signal is leaking or spring is too soft.

If your waist gate is hooked there it will read the lower pressure and close which will cause a boost spike. Get how it works?

Since the pressure difference is for such a small amount of time the wg will not have time to react (due to mechanical delay) before the engine consumes the pressure differential.

 

[Breezio69]

Hook the wg to the j pipe, as already stated. I had a small amount of creep (enough to hit fuel cut) have a bung welded on to the j pipe and a get a mbc.

I had a shop weld on an aluminum bolt spacer from home depot then drilled and tapped it myself for 90* barb to fit the 1/8" line... people can weld thin material, how do you think they get the thin j pipe on a 1/4" flange?

 

[NHerron]

Yeah, with the right welder and skills.

How many common exhaust shops can skillfully weld crappy and thin ebay aluminum piping. Not an impossible place to find at all but certainly not as easy as steel.

 

[hazmat6135]

If you have a good intercooler your not gonna see much pressure drop. I was pointing out where you'll see a big difference is on either side of the throttle body. And it will cause boost spikes. yes they may only be for a slit second but when your at 7000rpm's a split second is all it takes for a spike to show up, cause detonation, and wreck your day. And lastly yes steel is easier to weld but any shop that has a tig and a decent welder working there should have no problem with that.

 

[dsmjunky737]

What kind of shops do small welding jobs like that? Like speed shops and exhaust shops?

 

[92AWDHX40]

There is one here He's cheap.

 

[NHerron]

Why are you even talking about that when OP is talking about straight up WOT? And if that isnt enough to forget the throttle body theory, the OP removed the actuator completely and let the flapper hang totally open (not limited to its puny 30* opening). And it still boosted and spiked at the end. SO, this is a lack of back pressure. I should know, I'm actually in the same boat.

 

[Breezio69]

Take the aluminum to a machine shop with $40 and call it a day... most exhaust shops wont be capable of welding aluminum because they use steel for exhausts. Where as a machine shop repairs heads and fix aluminum parts all the time. Just call ahead and say hey I have a tiny job I need done, asked if it can be done same day. If you took a barb fitting I'm sure they put it.in as well

 

[dsmjunky737]

I'm looking at universal 3in. Cats on summit racing and there's two different styles a normal looking cat and another style spun there round. Is there any real advantage to either.

Spun cat