BAD Boost Creap

[4Motion4g63]

Ok I have been experiencing boost CREAP really bad Lately but have always had some in some form......

Right Now I have a Evo III 16g, 2g Manifold, FMIC, GM MAFT, With a Greddy TypeS BOV, and a Slowboy Red MBC, My exhaust is a Apexi 3'' all the way to the turbo... It is set to 10lbs but
Rises to 20LBS!, Even with the MBC bypassed it still does it....

I do have a Decent Boost leak on my throttle body that still needs to be fixed also... But would this cause such a bad boost creep? It spools, Hits 10lbs then it progressively climbs up to where it wants....It Use to do this before but usually was around 5lbs of extra boost! All the time it does this its WOT.....

A few other problems are, VERY high fuel trims *(130 on all at WOT)*, Lots of Knock full counts, and it just seams like it Falls flat on its face after 10lbs....
Im sure that the 20lbs is causing most of the knock and fuel to dump...

 

[Boost92awd]

First off the 16g's are known for creeping. You are going to want to do this.

http://www.dsmtuners.com/forums/art...oler/186525-how-cure-boost-creep-porting.html
http://www.dsmtuners.com/forums/art...boost-creep-modified-wga-peepers-mod-how.html

Then porting your manifold and porting your o2 housing will also help.

 

[daren_p]

Do some searching on here & you will find tonns of info on the evoIII with creep & you'll also find lots of answers on how to solve the issue. The best advice would be to get your fuel system upgraded & run 20 psi where that evoIII should be run But as linked above proper porting (not the porting that most vendors do) solves the creep in most cases. In the porting link posted above, don't worry about removing material behind the flapper arm so it opens to 90 deg as the flapper travel is limited by the WG actuator, which only opens about 45 deg (if that). To add to that article I also like to smooth out the abrupt transision on the WG outlet wall thats directly in the flow path.

 

[4Motion4g63]

Thx Im not sure If this hasent already been done, Since I bought it from a friend who Probably did these mods already, What If anything else could be the culprit...

 

[4Motion4g63]

I checked with The Former owner of My turbo, And All the supporting mods have been done already, Even has a larger Flapper and been clearance to Open fully....

So what Else could be the problem......Bad MBC, Its a Slowboy red, Mounted Firmly and Kept away from heat....And If I remember right, It creeps the same with it Looped without a MBC...

 

[turboglenn]

YOu said it does it without a boost controller hooked up so i don't think it's the MBC by any means. If teh turbo has been properly ported with a larger flapper is hsouldb't be creeping ( are you SURE your friend wouldn't just tell you what you wanted to hear and not have done the porting??? )

The best option would be to ahve some one who can actually weld cast iron and have them put an external flange on your exhaust mani. RRE used to do it and still may but i haven't looked at their page lately

 

[4Motion4g63]

I Trust that it was done Correctly, He has built dsm's for 12 years now...
So nothing else will cause Dramatic boost creep with the exception of a MBC?
Possible something in the WG broken, or would it cause it NOT to boost, I have Removed the Actuator arm and IT would NOT build boost past 2lbs to 5lbs....

He Ran 380HP, With the same turbo at 21lbs, Without any Boost creep issues, But also had O2 Dumped.....

For Reference Of my setup and my Install, Running line Off Nipple From turbo to Long side * Inline with screw * And Short Side to Going to Actuator...

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[turboglenn]

It just hit me, i've seen dramtic boost creep/spike from having the exhaust cam off by a tooth (retarded direction) and this was on a 14b he couldn't keep it under 19 - 20 psi either and that was using stock boost control solenoid on the stock ECU on basically an all stock car. (2g with stock exhast, K&N FIPK, 1g BOV and a 14b and boost guage are his only mods)

Check your timing marks !!!

16g's are known to creep, but a properly ported one shouldn't do much more than a psi or 2, at this point i'm really thining cam timing

 

[4Motion4g63]

Thx That May just be a Issue since I recently did the timming....

I dont think it is off but hey may just be it...

 

[flyboy346205]

I had the same problem with my 16G before... Only mine went all the way to 25 psi! Guess what fixed my problem... a tubular 02 housing with dump tube from slowboy racing. No more creep!

 

[4Motion4g63]

Timing checked its Good....

I am gonna switch out the WG actuator Possibly not fully opening
In my case It may need the same Route....

Whats a Good Waste gate combo, Dunno if I want dumped or not probably not but hey It sounds so wicked, How big Should I go... I plan on Running 21 to 24lbs from my 16g so I really dont want CRAZY boost just a Good Moderate street car that spools quick....

Tail 38mm and a Punishment Racing 02 back into the exhaust...

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[Mr Peepers]

Ok I have been experiencing boost CREAP really bad Lately but have always had some in some form......

Right Now I have a Evo III 16g, 2g Manifold, FMIC, GM MAFT, With a Greddy TypeS BOV, and a Slowboy Red MBC, My exhaust is a Apexi 3'' all the way to the turbo... It is set to 10lbs but
Rises to 20LBS!, Even with the MBC bypassed it still does it....

I do have a Decent Boost leak on my throttle body that still needs to be fixed also... But would this cause such a bad boost creep? It spools, Hits 10lbs then it progressively climbs up to where it wants....It Use to do this before but usually was around 5lbs of extra boost! All the time it does this its WOT.....

A few other problems are, VERY high fuel trims *(130 on all at WOT)*, Lots of Knock full counts, and it just seams like it Falls flat on its face after 10lbs....
Im sure that the 20lbs is causing most of the knock and fuel to dump...

Boost creep is not a MBC issue nor boost leak issue. It will also go up to the same psi no matter what the MBC is set at unless of course it's over the psi it creeps to. You can bypass the MBC all together and it won't affect creep.

Your ECU(130% LTFT) is likely adding fuel to compensate for the leak at the throttle body(perhaps among others). The LTFTs are only changed during close loop and not under WOT.

Boost leaks will also cause your car to run rich during boost.

I checked with The Former owner of My turbo, And All the supporting mods have been done already, Even has a larger Flapper and been clearance to Open fully....

So what Else could be the problem......Bad MBC, Its a Slowboy red, Mounted Firmly and Kept away from heat....And If I remember right, It creeps the same with it Looped without a MBC...

This tells me that it may not have been done correctly. As stated before, the flapper is stopped by the WGA travel before the housing(clearanced to open fully) gets in the way. I would check to make sure the WG hole was enlarged to take advantage of the larger flapper, otherwise the flapper isn't helping one bit.

I Trust that it was done Correctly, He has built dsm's for 12 years now...
So nothing else will cause Dramatic boost creep with the exception of a MBC?
Possible something in the WG broken, or would it cause it NOT to boost, [B]I have Removed the Actuator arm and IT would NOT build boost past 2lbs to 5lbs....
[/B]
He Ran 380HP, With the same turbo at 21lbs, Without any Boost creep issues, But also had O2 Dumped.....

For Reference Of my setup and my Install, Running line Off Nipple From turbo to Long side * Inline with screw * And Short Side to Going to Actuator...

Bingo. This tells me that it's the flapper travel that is a big part of the creeping problem. When you unhook the WGA it allows the flapper to open fully(farther than the WGA allows it to) and keep the boost down.

He had no creep at 21psi simply because of teh fact it only creeps to 20 or so in the first place. The o2 dump most likely wasn't the solution.

Timing checked its Good....

I am gonna switch out the WG actuator Possibly not fully opening
In my case It may need the same Route....

Whats a Good Waste gate combo, Dunno if I want dumped or not probably not but hey It sounds so wicked, How big Should I go... I plan on Running 21 to 24lbs from my 16g so I really dont want CRAZY boost just a Good Moderate street car that spools quick....

Tail 38mm and a Punishment Racing 02 back into the exhaust...

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Unless the WGA body is severely bent or damaged I doubt it is opening any less than all the other stock ones; you can pressurize it and see, though. It should travel about 3/8".

Why don't you just tune for 21-24 psi then? I don't see a reason to pay extra if you plan on running above what it's creeping to in the first place. Fix the boost leaks, read up as much as you can on tuning, and get a nice tune on it. Or, have someone else tune it if you don't feel comfortable.

I would suggest porting but tuning it for the psi you want seems like a step in the right direction without any unnecessary work.

 

[4Motion4g63]

Your right Mr peepers, But the Mods Were done correctly the Dump hole is Larger Also....
I Just dont think my motor is in any condition to run at 21lbs of boost, and I need to keep it Going for a few more months, before I invest into a Rebuild, or I will halfto cut corners and go cheap on my Rebuild.....

When I get time, I will be Installing the Rest of my Fuel system to Run a Good 21LBS setup, I already have a Wally 255Hp, DIY 550cc, and A Apexi NEO, With a already installed Areomotive FPR....

I just want my Turbo to Build boost BUT not OVER what i need ATM... I just want to Cure the creep problem for Peace Of mind......Although its pricey, External Is what i want, Just wanted to rule out any other sources of Creep, Or find out that after its blown up my motor...
We suspect the stock Actuator is faulty or has a hole in it somewhere....