Ebay O2 = Boost Creep * Help
May 19, 2006, 10:33 AM
#47
I think what is going on here looks like boost creep, but isn't. Here is my concern with the boost creep/higher O2 flow theory. If the turbo is maxed out and you can't hold any more boost, as I think the orininal poster's situation was, it is not posible to get boost creep unless the restriction somewhere goes UP (decreasing VE). In order to creep you need to have more flow capacity in the compressor, which any of us with cams and the usual mods simply don't have. And to increase flow through the O2 housing, you have to increase flow everywhere else too. It sounds to me like this piece is worse than the stock unit, but without one to try I can't say for sure, so it's just my personal theory.
Another thing to consider is if the turbo is maxed out, trying to increase flow more is a waste of money and time. This is why some poeple with intake/exhuast/cams are making the same power as poeple with a laundry list of mods that seems to go on forever. Achieving more airflow at lower boost is a worthy cause, but only for pump gas. Race gas is the great bandaid, and accomodates any extra heat you put into the air. At least well enough that gains/losses are negligible if the turbo is maxed out. I would go back to the stock piece.
Another thing to consider is if the turbo is maxed out, trying to increase flow more is a waste of money and time. This is why some poeple with intake/exhuast/cams are making the same power as poeple with a laundry list of mods that seems to go on forever. Achieving more airflow at lower boost is a worthy cause, but only for pump gas. Race gas is the great bandaid, and accomodates any extra heat you put into the air. At least well enough that gains/losses are negligible if the turbo is maxed out. I would go back to the stock piece.
May 19, 2006, 04:33 PM
#48
As I posted in another thread.
If you are "boost spiking" after your 02 install, chances are, that your WG passage opening where it routes back into the exhaust passage is too small, causing some minor backpressure on the WG passage only, making it difficult to release gasses from the WG and directing more flow out of the exhaust.
Before I installed my 02 housing I noticed the hole was not as big as it should be so I smoothed it out and opened it up a bit with a die grinder, this is something you guys may want to look into before installing theese 02 housings. Since the metting point between the two passages is not as smooth as a stock 02 housing, and causes more turbulance, everything you can do to improve this will make your boost control more accurate.
Before I installed my 02 housing I noticed the hole was not as big as it should be so I smoothed it out and opened it up a bit with a die grinder, this is something you guys may want to look into before installing theese 02 housings. Since the metting point between the two passages is not as smooth as a stock 02 housing, and causes more turbulance, everything you can do to improve this will make your boost control more accurate.
May 19, 2006, 09:21 PM
#49
The higher the gear the more sustained load you are putting on the engine, the more likely you are to have creep when the wastegate is on the edge of it's ability to handle your boost control needs.
Your best option in a situation like this is to go to a better WG setup by either porting your single flapper out or switching to the dual flapper setup. A less effort / less expensive option is to go back to a more restrictive O2 housing.
Your best option in a situation like this is to go to a better WG setup by either porting your single flapper out or switching to the dual flapper setup. A less effort / less expensive option is to go back to a more restrictive O2 housing.
i agree with this.....i have stock o2 housing and alky kit.,..i got same problem ...boost creep on only higher gears
for ex---1,2,3 gear i see like 25psi and 4and 5 i see arou nd 30psi....(only if i shift gear in low rpm and goes WOT)
this is normal or what
note) i turn up the boost as high as possible with mbc,,,
