New Exh Mani; now boost creeping badly?

[PsiRemix]

First off, I want to say that whenever I have a problem or question about my car, I always take hours upon hours to search out the the answers on these forums; my logic is that, if I am having a problem, somebody out there has already had it, and found out a way to fix it. This site is always there when I need it. This is my first post on help so bear with me, b/c I can seem to find the answers I'm looking for.

This is long... sorry I need a few questions answered.

I've had my Evo 3 for just about 2 years now, and never had a problem with boost creep, although there are many speculations that 16gs are known for creeping issues. I was always able to hit my set boost setting on my mbc, and have it hold; right on the mark. I installed an O2 dump, just in case a creep issue were to arise. I should put in that I drive my car is an A/T as well.

I put the car away for every winter, as usual, and while it was stored, I decided to install a new exhaust manifold, b/c my stock 2g mani that I have had for almost 3 years has had a bolt plugging a tapped-hole on the first bung, b/c the previous owner tapped the hole slightly too large to fit a 1/8 npt. I installed a turbochargers.com GT manifold, and once everything was back together, I took a test drive and found that I now have a serious boost creep issue. At about 9~10psi, the waste gate opens, and that is at MAYBE 1/2 throttle. At 3/4 throttle, I creep up to 18psi, then 20+. I am afraid to go WOT because of what it will creep to.

I searched out a few threads and posts, and tried a few things to see if anything would help. I disconnected the MBC and ran a line directly to the actuator nipple. The problem I have here is that my Evo 3 doesn't have a a compressor nipple, so I've always ran my MBC off of a tee for the BOV to the intake mani ( I know, this is bad, but I dont have another tap able boost source, without drilling into my J-pipe, which I havent attempted as of yet. If you guys know what I should go about doing about this, PLEASE let me know. ).
When I ran the direct line, I hit WOT and hit 10~11psi, then crept up to 16 when I let off the throttle. I decided to reconnect the MBC and turn it to the lowest setting, and when I hit WOT, agian it hit ~10psi, and slowly climbed to 16. This was on the lowest boost setting. I guess this rules out the boost controller.

Next I disconnected the actuator arm from the pin, to see if my flapper opened freely with my fingers. It opened fine, so I reconnected the arm and applied about 12 psi to the actuator and the arm opened the flapper, but I noticed that with the arm connected, it only opens half way? Is that normal? Without the arm, it opens a full 90 degrees.

I have a hard time believing that this new manifold is flowing THAT MUCH air to all-of-sudden be causing this serious creeping? Unless that is the issue, then I will be surprised. I have had NOTHING ported in the past, nor on anything on I am running on my setup now. It seems on other threads of creeping issues, everyone is very quick to suggest porting the flapper area, or porting the turbine housing. Another solution I've seen suggested many times is going external. I never did b/c I thought with an Evo 3 its not really needed.
Are these things (porting, external, upgraded flapper) all-of-a sudden needed when it was never an issue before with my old mani? Was the plug on my stocker a form of exhaust leak diverting some of the gases out before the turbine housing? Another thing im wondering is if I bent the actuator arm while the turbo was out and resting on my desk for a couple weeks?WTF Im so confused. What else could it be? Am I looking in the wrong direction?

I appreciate ANY and ALL help! Thanks in advance! If I somehow missed a thread JUST like this one, sorry for making a new one!

 

[Steve93Talon]

It sounds like you've done your troubleshooting well. The only thing I can think of with regards to swapping manifolds is that the knock-off doesn't have the same style of "splitter", the thing between the front and rear runners. That could affect the direction of the gas as it enters the turbo and cause less air to flow through the gate. The only other thing could be a boost leak before the turbo that was corrected during the swap.

You didn't mention what you've got for a flapper door. Is the wastegate hole ported? If so, is it teardrop shaped at the transition or is it just a sharp turn? And yes, the flapper will only open partially. Some people will grind away material behind the arm to make it open more, but this is only so you can get in there better for porting. Once the actuator is back on, it only opens partially anyway.

You could easily tap an 1/8" NPT hole on the J-pipe or first IC pipe and use that for your boost source. The closer to the turbo it is, the more quickly the actuator will respond. Keeping the vacuum lines as short as possible will also help.

Lastly, if it's creeping to 16, run more than 16 psi. You should be able to run 20-25psi on that turbo if you've got the right size IC, injectors, a cold air intake, and something to control timing like DSMlink. Just log, watch for knock, and keep your AFRs in check.

 

[PsiRemix]

You didn't mention what you've got for a flapper door. Is the wastegate hole ported? If so, is it teardrop shaped at the transition or is it just a sharp turn? And yes, the flapper will only open partially. Some people will grind away material behind the arm to make it open more, but this is only so you can get in there better for porting. Once the actuator is back on, it only opens partially anyway.

Lastly, if it's creeping to 16, run more than 16 psi. You should be able to run 20-25psi on that turbo if you've got the right size IC, injectors, a cold air intake, and something to control timing like DSMlink. Just log, watch for knock, and keep your AFRs in check.

Thanks Steve, the flapper is stock from the Evo3. So do you suggest that I get that exhaust housing ported? I have the Greddy FMIC, 510s, injen intake, although no logger anymore, and no DSMLink. Im worried about trying to run 20-25psi, b/c Im worried about the knock. Thanks for your help though!

 

[CanadianTSi]

Classic Case of boost creep.

Looks like your going to have to pull the Turbo and port the entrance to the wastegate.

OR get the proper supporting mods to run 20psi

 

[2gAWDTalon]

I vote 20 psi!

 

[staticbrainwash]

I also vote for getting the supporting mods for 20psi if possible. AND just to be safe, also port. Can't hurt , and it will just help flow and spooltime.

 

[PsiRemix]

I also vote for getting the supporting mods for 20psi if possible. AND just to be safe, also port. Can't hurt , and it will just help flow and spooltime.

So, porting is my major choice in direction I guess then. Porting will help the flapper open fully though? The actuator arm doesnt seem to want to open that far. Thanks agian guys.

 

[staticbrainwash]

The arm will never open a full 90* like you would think. That being said, You have to open up the parts that do let gasses through so you get better flow. Better entrances, better exits, and larger openings.

There's a vfaq of porting on a 14b, which, is pretty much the same. Check it out.

 

[Steve93Talon]

Here's a good example of what a ported wastegate passage should look like:

http://linux.forcedperformance.net/merchant2/graphics/00000001/footer/red/red_th.jpg

That one's set up for external on o2, sou you obviously wouldn't want to remove quite that much material. You want to leave about 2mm of seat area for the flapper door to seal. Basically, taper the entrance to the flapper hole so it's not a sharp turn and open the hole as much as you can while maintaining the seat edge.

 

[staticbrainwash]

http://www.vfaq.com/mods/porting-turbo.html

Thats going to get you just what you need man. Better flow, controlled boost.