740 Turbo Brick

iTrader: (2)

I know boost creep is a widely discussed topic here, but I couldnt find an answer in the other threads about it.

Evo 8, 10.5/20G, Stock wastegate and actuator, O2 Dump, Street tuned for 26 psi, Have a MBC but am currently running boost signal line straight from compressor housing to WGA for the clutch "Break in" period.

Did some normal grocery getting driving to get a feel for the clutch and let it wear in a little. Gradually gave it more and more boost until the wastegate opened at 12 psi, and held there. Later on that night I took a friend for a ride, and noticed the car was pulling much harder after 6k rpm. Checked the boost gauge, 12 psi by 3k, held until 6-6.5k and then went straight to 20. I dont know if it would keep climbing or not, I got out of the throttle before things got sketchy. Any idea whats going on here? Im being told obviously when its colder, you get denser air etc, and slightly more boost. But Im thinking 12-20 psi creep is a little out there. In the summer I normally hit 24-26 psi with the boost controller, and have no creep issues, and the boost only tapers off to about 21 by redline.

https://www.facebook.com/photo.php?v...34772638830774

740 Turbo Brick

iTrader: (2)

Hmm nothing? Is this is a sign from my car that it doesnt like cold weather?

740 Turbo Brick

iTrader: (2)

Up for Video

ProjExtremis

Man I did research as well about my creep issue, and finally made a posting up here. Didn't get any help for a couple days until finally one or two responses, but nothing solid. I think we are both screwed lmao. I'm going to just grab a pen and paper and write down what it does in every gear because it seems to do different things in different gears. With mine, I have a forge wga, a hallman pro controller, and tuned for 23lbs. I'm trying to get my wga to get me to about 18 and hold it, so I can make up the rest with the controller. Only mine will hit 17 or 18 and by redline it has climbed right up....frustrating

ProjExtremis

I'm like STAHP

740 Turbo Brick

iTrader: (2)

Yeah I dont know if Im literally out flowing my wastegate or what. Last year I had the boost controller set at 25-26 psi and it always hit full boost at tapered off to 21 or so. This is the first time Ive tried to run less than that. My plans for next year is to start buying a setup for a 6262, so I might just have to deal with it until then.

sparky

iTrader: (1)

if you are tuned for 26#, then why get out of it at only 20 PSI? What was the ambient air temp difference between the daytime high and the evening low?

Incidentally, each 10* F. drop in air temp is worth one additional PSI increase in peakboost level.

740 Turbo Brick

iTrader: (2)

Well at the time I first noticed it we were coming up to the end of the parking lot pretty quick lol. But the video I took was a full to redline pull. Im mostly just a little confused as to how it could jump up that high. I wanted to keep the boost somewhat low while I break the clutch in (I keep saying break the clutch in, but I guess they dont technically need broken in).

Im thinking I might just slap the MBC back on, turn it to like 15 or so and see if it holds or creeps again. If it creeps again, it might just be time to get a 6262 turbo and all the components to support it.

sparky

iTrader: (1)

I just want to be absolutely sure that I am understanding you..... You are controlling boost via the actuator. You have connected a piece of hose directly from the nipple on the actuator cannister to the nipple on the compressor discharge pipe nipple(J-pipe)?

You have an open dump and when you say that WG opens at 12#, it is because you determine that it is opening because of the audible sound due to the open dump?

It is not a stock VIII turbo, right? It has a 20G compressor wheel. Does it have the VIII compressor housing, 10.5 turbine housing, stock TD05 turbine wheel and a stock MHI actuator. Is that about the size of it? No catalytic convertor? Stock plastic DV? What O2 dump?

740 Turbo Brick

iTrader: (2)

Basically yes, but its an aftermarket j-pipe and compressor housing, there is no nipple the j-pipe, its on the outlet of the compressor housing. But yeah, its a 3 inch piece of vacuum line going from the actuator to the compressor housing.

It has an open dump, and I base it opening at 12 due to it spooling quick to 12 and stopping, at which point you can hear it because it gets very loud. It doesnt lag or anything, when I run 20+ on a MBC it always goes straight to full boost by 3.5K and you can hear the dump open when it gets there.

Correct, non stock turbo, Evo 9 10.5 Hotside, Not-sure-on-brand 20G wheel and compressor housing, Evo 9 Actuator, 3" Turbo back exhaust with no cat, HKS SSQV BOV ( have a forge DV on a shelf somewhere) and I believe its a Megan racing o2 housing w/dump. Also has a megan racing tubular manifold. These are all P.O. mods. Did you see the video I posted in the first post?

sparky

iTrader: (1)

You are tuned for 26#. But, the flapper is cracking open at a wimpy 12#. To be running 26# peak, I would want the flapper valve closed until at least 18# bare minimum. 23-23# preload would be better IMO.

Since you are running the actuator straight off the compressor nipple then try increasing WG spring pressure via clockwise rotation of the turnbuckle on the end of the actuator rod.

Try at least 3 complete 360* rotations to start with. The stock VIII actuator ain't much good for running much more than 22-23# peak. It aint no good for 26# for sure unmodded. Maybe you can hold 25-26# if we mod it.

740 Turbo Brick

iTrader: (2)

I might give that a try after work this week. Thanks for the info!