Help Me Eliminate My Boost Spike/Creep

Cgillies86 · Feb 2, 2005

Ok, I just bought this dsm; and it has massive boost creep. I don't know much about hese cars so I need help with eliminating the boost creep. If i floor the car the boost goes to 8 psi. Then at 4k it shoots to 15psi, at 5k the boost reaches 22 psi, and at 6k it skyrockets 30 psi. I pretty much stopped flooring the car because it boosts so high. I am not really sure what is causing the boost spike so any help would be appreaciated.

My Cars Mods:
Full 3 inch Exhaust Downpipe and back, Test Pipe, Hybrid Connection O2 Housing 2.5 inch, 2g Exhaust manifold, 14b Turbo, Dejon Tool 2.5 upper and 2.5 lower intercooler pipes, 3 inch air intake pipe, 7 inch K&N air filter, SBR boost controller, MAFT, GM MAF Blow-Thru, Walbro 255 fp, Aeromotive FPR, 450s, S-AFC II, pocket logger, EGR block-off and All other Emissions

Temperature was 30 degrees F.

Let me know if you have any ideas on how to reduce this boost creep.

importboost · Feb 4, 2005

all you need man is a bigger o2 housing.. that will eliminate your spiking, o and i would invest in a nice turbo controller too, i love my GReddy pro-spect b

ikickuintheball · Feb 4, 2005

A better o2 housing will help, but it probably won't eliminate it.

It's not a pro-sepct b. it's a greddy profec-b.

Also, you have boost creep, not a boost spike. A boost spike is when you first start to boost, and it goes higher than you set it to, but settles back down to where you have it set quickly. You can have both, but don't mix them up because there are different ways to fix both.

Good luck!

nuggets · Feb 4, 2005

id look into getting an 02 sensor housing with a DUMP. yes, they are loud. find some videos in the hangout forum if your not sure what im taking about. From what i have read, the dump tube on the 02 housing helps eliminate boost creep a shitload.

PaleDSM · Feb 4, 2005

With creep that bad I would suspect there is a problem with the wg opening all the way. Pressurize the actuator and make sure the flapper can make its full swing to open unrestricted.

Porting of the 02 housing, a dump, or a tubular O2 housing generally help with boost creep by lessening the restriction through the O2 passage.

A full 3" exhaust is very free flowing so the exhaust gasses would prefer to take the path of least resistance. Opening up the wg path or introducing some back pressure to the exhaust will work. Maybe a cat. for now.

99gst_racer · Feb 4, 2005

Yup, classic creep caused by a free-flowing 3" turbo-back. Fix it w/ one if these......

You must be logged in to view this image or video.

38mm Tial's are only about $200 right now. And it would definatily fix your problem. :thumb:

oldman · Feb 4, 2005

All that mention above including dump tube, bigger o2, bigger flapper door and even a external on a o2 will help but not eliminate unless you port the turbine inlet so you can see the wastgate passage. The problem is the entrance not the exit of the wastgate path. There are many threads that focuses on the porting, search and you shall find.

Cgillies86 · Feb 6, 2005

I think I'll start by getting a new O2 Housing. There is a tubular 02 housing at SBR;Do you think this will do the trick or should i get the dump?
http://www.slowboyracing.com/shop.php?sid=&cat=1104

Cgillies86 · Feb 19, 2005

I put the tubular O2 Housing on my car; and, my car creeps exactly the same amount. The boost just skyrockets to 22-30(maybe higher) depending on how fast I let off the throttle. So, should i port the wastegate open next or what?

guitarXgeek · Feb 19, 2005

You NEED to port the turbine inlet! You won't see any more control of boost creep if you don't get to porting that thing. Porting the turbine inlet and the path to the WG in the turbine inlet is crucial in order to get maximum performance from the turbo and the wastegate. www.vfaq.com has a wonderful write-up with pictures and all of what you need to do when porting the exhaust manifold/turbine inlet/o2 housing. If you can't do the port work by yourself, send it to SlowBoyRacing or Forced Performance.

rowlex · Mar 5, 2005

Hey....if it works let us know mine is creeping like a b*tch to. Ive got a 3" dp, a 2.5 inch dumped tubular housing....creeps terrible...

flinguist · Mar 5, 2005

This will eliminate creep. http://www.bullseye-power.com/product_info.php?products_id=57

rowlex · Mar 5, 2005

Not bad. Not bad at all. Good price to. It's too bad an external gate will cost me less, otherwise I'd get it. Thanks for the link :thumb:

guitarXgeek · Mar 5, 2005

The gate itself may cost less, but getting it on the manifold/o2 housing will cost you easily $100 more

flinguist · Mar 7, 2005

Don't put the waste gate on the O2 housing, it may not work if you do, because flow is still limited by the waste gate hole/flapper. Mount it on your exhaust manifold. Buschur Racing has a price quote of 75 bucks to put a waste gate flange on your manifold.

oldman · Mar 7, 2005

Alright I'm going to suggest this one more time as myself and a couple others have already mentioned on this thread. You need to knock off more material on top of the wastegate entrance in the turbine inlet to ease the path of the airflow to the wastgate door. You then need to port the area behind the door so it can open up more as per vfaq. These are the two most cruicial steps to porting for creeping purposes. I've done this on a 16g that used to creep to 24psi+, now it holds 12psi to redline in every gear. Good luck.

rowlex · Mar 7, 2005

oldman said:
Alright I'm going to suggest this one more time as myself and a couple others have already mentioned on this thread. You need to knock off more material on top of the wastegate entrance in the turbine inlet to ease the path of the airflow to the wastgate door. You then need to port the area behind the door so it can open up more as per vfaq. These are the two most cruicial steps to porting for creeping purposes. I've done this on a 16g that used to creep to 24psi+, now it holds 12psi to redline in every gear. Good luck.

Would this need to be done (porting the outside of the wastegate door so it can open) on a o2 housing that is tubular and has a 1.5" dump?? I think I wanna try this before I blow 300$ on a external gate setup... also..with my setup 2.5" o2 housing w the 1.5" wastegate dump...would I need to port the actual wastegate hole? Or would porting the path to the hole work? I'd like to see if i can port it w/o removing anything but the manifold...

oldman · Mar 7, 2005

rowlex said:
Would this need to be done (porting the outside of the wastegate door so it can open) on a o2 housing that is tubular and has a 1.5" dump?? I think I wanna try this before I blow 300$ on a external gate setup... also..with my setup 2.5" o2 housing w the 1.5" wastegate dump...would I need to port the actual wastegate hole? Or would porting the path to the hole work? I'd like to see if i can port it w/o removing anything but the manifold...

I've just finished porting my new sbr gt12 and tubular o2, it's not easy because you can't really port the o2 execpt for the plange area so it can mate perfectly with the ported turbine side. It shouldn't be as hard for you because you have a 34mm wastegate and mine has a 38mm. I ported the turbine wastegate exit so the door is paralell to the airflow and not hitting the o2 wastegate passage. I've not install the turbo yet but if it creeps still I will sell the tubular o2 and port match my gt12 turbine to my stock o2 housing which was ported to exactly 2.5".

99gst_racer · Mar 7, 2005

A manifold mounted external WG will solve boost creep, period. And yes, it is worth the money.

oldman · Mar 7, 2005

99gst_racer said:
A manifold mounted external WG will solve boost creep, period. And yes, it is worth the money.

Yes it will but at the same time it will increase temperature in the engine bay and creat unwanted noise, I'm trying to keep the appearance and noise level as much stock as possible but I'll have go that route if porting doesn't do it.

99gst_racer · Mar 7, 2005

oldman said:
Yes it will but at the same time it will increase temperature in the engine bay and creat unwanted noise, I'm trying to keep the appearance and noise level as much stock as possible but I'll have go that route if porting doesn't do it.

If noise is an issue, the dump tube can be routed back into the downpipe......

Man, the appearance and the noise are the fun parts.

oldman · Mar 7, 2005

99gst_racer said:
If noise is an issue, the dump tube can be routed back into the downpipe......

Man, the appearance and the noise are the fun parts.

Not for an OLDMAN like me.

B005T3DT5i · Mar 7, 2005

and another note... the bigger the inturnal wategate flapper (38mm) the more trouble it has holding high boost (20+)...so a exturnal wastegate is your best bet for high , horse power goals... :talon:

Cgillies86 · Mar 13, 2005

Well, I am almost finished porting my wastegate. The Flapper door opens all the way now. The hole behind the wastegate door has 52% more area, it is basically as big as I could go with the stock flapper door(it barely seals). On the turbo inlet side, i made a few notches so there is a more direct route to the wastegate. Next I am going to just smooth out the edges on the turbo inlet side so the air will want to flow into the wastegate. I really hope this will fix my boost creep problem. If i get a chance I will post some pics of what I did.

oldman · Mar 13, 2005

Cgillies86 said:
Well, I am almost finished porting my wastegate. The Flapper door opens all the way now. The hole behind the wastegate door has 52% more area, it is basically as big as I could go with the stock flapper door(it barely seals). On the turbo inlet side, i made a few notches so there is a more direct route to the wastegate. Next I am going to just smooth out the edges on the turbo inlet side so the air will want to flow into the wastegate. I really hope this will fix my boost creep problem. If i get a chance I will post some pics of what I did.

The key here is the inlet, I don't know what a few notches means but this should give you some idea what it should look like when it's done.

http://pg.photos.yahoo.com/ph/tarantulasweb/detail?.dir=e58b&.dnm=1668.jpg&.src=ph

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