Boost Creep!!!

MATCHBX · 10-21-2003

I just had it happen to me and I'm wondering what I can do to combat it.

I just installed my 3" catback and 2.5" downpipe. I have a small exhaust leak also that will be fixed shortly.

Here's the scenario:

I took it out after installing it to see if everything would be ok. Well I hit the gas and I boosted to 15psi. Then out of the blue it started rising to 19psi!! It scared the hell out of me. I proceeded to turn my boost down to 10 psi but it still creeps up to about 14-15.

Is there a fix for this or what? I know there were threads before but I don't have the old boards website anymore. Please help.

Thank you
Erik D

**1ViciousGSX** · 10-21-2003

Might be time for a better flowing O2 housing (ported EVO III or 2G, stainless steel)

PLEASE READ THE FORUM RULES
What turbo are you running? Stock internal gate?

A//// Guy · 10-21-2003

Only fixes are bigger flapper and turbo porting or smaller exhaust...

MATCHBX · 10-21-2003

Sorry Mike.

Stock turbo with stock O2 housing. I think I will go to a ported housing and see what that does.

Thanks for the info (and the tolerance of a Tech section newbie).

john · 10-21-2003

I agree with the both of them. Order a 34mm flapper from TRE (as I did) and pay Raptor to install and port your turbo. You will also want to upgrade to a better o2 housing or have yours ported. I always had boost creep in cold weather. I upped to a o2 housing with a dump and it didn't help. Then, I had raptor put in the 34mm flapper and port the turbo. Now it is all gone.

MATCHBX · 10-21-2003

How much did you get the flapper for?

FORSFED · 10-21-2003

You may want to check and see first if Elite carries them, otherwise I bought one from Slowboyracing for $28 if I remember correctly. TRE is the other place that sells them as mentioned before for I believe the same price or close to it.

redline · 10-22-2003

i had nasty creep for awhile. i ended up porting a 2g o2 housing and removing the divider between the wastgate outlet and turbine outlet on the o2 housing. this helped greatly, but didn't fix it. i then ripped off the turbo ported the turbine inlet spent most time on the area going into the wastegate hole ( taking out the sharp bend and making a smoother transition) as well as slightly enlarging the hole itself. doing that along with removing the step in the exh. mani. and port matching it all togethar killed the creep. took some time, but well worth it. this was on a 14b in a 2g with the stock wastgate flapper and 3in dp w/ no cat.

niterydr · 10-22-2003

as stated above, you need to find a way to promote gas flow through the wastegate hole since you promoted flow through the exhaust wheel (hince causing it to spin harder/faster, which made it overrun the wastegate acutator).
AKA either restrict the exhaust, or port/hog/upgrade other stuff.
good luck.

Raptor · 10-22-2003

Eric, I am probably Porting CVD's and upgrading his flapper this weekend if you are around, you can probably come see the finished product. I can call you when I am done if you are interested.

MATCHBX · 10-23-2003

That would be awesome!!! I want to see what I'd have to do. Right now I just keep my foot off of the floor until I can get the fix done.

**Shane@DBPerformance** · 10-23-2003

Super Bleeder!! · 10-23-2003

that too :idea:

**JET** · 10-23-2003

You don't actually need to put on a bigger flapper if you port it correctly. Running a bigger flapped means that you cannot run as high of boost. I had my 16g ported so that there was no creep with a 3" turbo back exhaust. The big trick is where to do the porting at.

john · 10-23-2003

I have had no boost problems on my 16g at 20psi. I guess I have only had it tuned for 20psi for a couple days until DR. Rick decided to work his tuning magic.
:censored:

Raptor · 10-25-2003

Quote:

Originally posted by JET@Oct 23 2003, 08:06 PM
You don't actually need to put on a bigger flapper if you port it correctly.  Running a bigger flapped means that you cannot run as high of boost.  I had my 16g ported so that there was no creep with a 3" turbo back exhaust.  The big trick is where to do the porting at.

While this is true in part in certain instances, it is not true across the board. Contouring the wastegate entry can help in some cases, but not all. The wastegate hole diameter becomes a bottle neck in many systems with increased exhaust flow. You can make the entry into the wastegate as free and easy a transition as can be, if the wastegate itself is too small it is still a restriction and will still cause boost creep. Larger flappers have been a consitant and proven method of controlling boost creep for many years and not without reason. As far as not being able to run higher boost, depends on the porting going into the flapper area and the diameter of the hole, it can be made too large for the diameter of the flapper and hense cause blow open at higher boost levels. The entry into the wastegate can be over-ported and also cause an issue with premature opening of the flapper, as well as causing an unnecesary turbulant path to the exhaust wheel itself. For a 34MM flapper, a wastegate hole of 28-29MM and a properly ported housing will most of the time control boost creep without causing issue with blow open or negative effects on flow to the exhaust wheel.

Personally I would only run an internal gate on smaller turbos (up to a 20G). They may work for larger turbos, but IMO, if you are going for that kind of performance, why settle for an internal gate.

Iceman · 10-25-2003

Quote:

Originally posted by Raptor@Oct 25 2003, 04:27 PM
Personally I would only run an internal gate on smaller turbos (up to a 20G). They may work for larger turbos, but IMO, if you are going for that kind of performance, why settle for an internal gate.

Cause going external costs to much

Raptor · 10-25-2003

Quote:

Originally posted by Iceman+Oct 25 2003, 05:56 PM--></div><table border='0' align='center' width='95%' cellpadding='3' cellspacing='1'><tr><td>QUOTE (Iceman @ Oct 25 2003, 05:56 PM)</td></tr><tr><td id='QUOTE'> <!--QuoteBegin-Raptor@Oct 25 2003, 04:27 PM
Personally I would only run an internal gate on smaller turbos (up to a 20G). They may work for larger turbos, but IMO, if you are going for that kind of performance, why settle for an internal gate.

Cause going external costs to much

[/b][/quote]
If you want to play, sometimes you have to pay. DSMers as a group are very resourceful and that is a good thing as far as getting a lot of performance for as little money as possible in general. I do personally believe though that there is a level where people try to save money in the wrong areas and skimp on things that really should be done right. IMO this is one of those things. If you are going large and are putting the money down for the big setup, it really isn't that much more initially to do it right and go with an external gate. It is all about how serious you are about what you are after and what you are willing to do to get it.

slowbubblecar · 10-26-2003

I like Mo's quote at elite. I think it is something like this, "If you want to play hard, you have to pay hard." BTW, an external isn't that expensive. my brother, 92tsiawd84, has an external tial 38mm sitting here. It cost around $250 shipped. If getting a bigger turbo, it costs $75-$100 for an internal WG and it still may creep. An external is $150 more and is less likely to creep. I would rather spend the extra money because it will be safer. Just my opinion though.

MATCHBX · 10-26-2003

I don't care too much for external because most of us already have larger exhausts and that's loud enough. You add the external and it's unbearable (IMO).