I was thinking it might just be from old age of the wastegate. If you go into depth and find anything keep us updated though, I'll do the same.
bic ddp question
- Thread starter Insidious Surmiser
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JustAnotherVictim
Supramania Contributor
I have hit fuel cut at stock boost after installing the BIC DDP, test pipe, and Blitz cat-back. When it was warmer, it was fine and boost would usually creep from the stock 6psi to 8-9psi. However, once the cooler weather settled in, I hit fuel cut consistently in 2nd and 3rd gear as boost crept up to ~10psi. The exhaust flows well so the small wastegate hole probably just can't keep up.
It could be worse though. On my Talon, when I finally got the full exhaust installed, I would get boost creep from the low teens to ~20psi on a Big 16G turbo (Mitsu turbo). I finally got rid of that boost creep with a dump tube on the O2 housing.
Boost creep is often hard to avoid with internal wastegates and big exhausts, but the problem is more noticeable on the Supras since they run such a low amount of boost in stock form. My solution has been to upgrade the fuel system (pump, AFPR) so that I can lower the airflow signal (SAFC) and hopefully avoid fuel cut. I'm not done with the install yet so I can't say how successful it will be.
It could be worse though. On my Talon, when I finally got the full exhaust installed, I would get boost creep from the low teens to ~20psi on a Big 16G turbo (Mitsu turbo). I finally got rid of that boost creep with a dump tube on the O2 housing.
Boost creep is often hard to avoid with internal wastegates and big exhausts, but the problem is more noticeable on the Supras since they run such a low amount of boost in stock form. My solution has been to upgrade the fuel system (pump, AFPR) so that I can lower the airflow signal (SAFC) and hopefully avoid fuel cut. I'm not done with the install yet so I can't say how successful it will be.
did you try to replace that vacum line? also, adjusting that little skrew on the side of the AFM does raise your full cut a pound or 2. iv had it done to mine and ran `12lbs on my old motor.
97TSiAWD said:
kinda what i was thinking... as i said... all i have is the dp, and a 3" straight thru muffler on the end of the dp.... doesn't even go past the door.... maybee i'll see if i can get the wastegate ported out, and put another wg actuator on while i'm at it
i will be getting a wideband soon, so i may do this, but for now.... i have no tuning or monitoring devices, so i'll leave it as it isagainstdawall06 said:
so, i guess this problem is actually pretty well-spread.... i'm beginning to seriously think the stock wg is too restricted
I am having the exact same problem. I was running a BIC DP for a year boosting at 10-11psi. (Wastegate shimmed). Last week i installed my new DDP and it creeps up to 14-15 psi!!! Usually only in 3rd and 4th gear. I hit fuel cut around 14psi.
I did a search on Supra Forums and I read something about porting the Wastegate hole.
Does anyone else know how we can fix this? I hate hitting FC... its pissing me off lol.
I don't have any boost leaks. This problem started as soon as i swapped the normal DP for the DDP.
I did a search on Supra Forums and I read something about porting the Wastegate hole.
Does anyone else know how we can fix this? I hate hitting FC... its pissing me off lol.
I don't have any boost leaks. This problem started as soon as i swapped the normal DP for the DDP.
I got the same probs w/ my 3" turbo elbow...I'm hitting FCO at 10psi also. But I know for a fact the waste gate flapper is not hitting anything and can open up completely.
I just figured it was my AFM?
*edit*
Maybe I'll swap the stocker on and see how things go after that.
I just figured it was my AFM?
*edit*
Maybe I'll swap the stocker on and see how things go after that.
There are a couple of things that can be done to prevent boost creep: you can get a larger wastegate flapper and bore out the wastegate hole or just go to an external wastegate. Personally, if the creep is limited to a max of around 10-11psi without hitting fuel cut (as I mentioned, I'm not done with the fuel mods yet), I will just live with it and make sure I have enough fuel to support that amount of boost.
That's why I like my Cooleze megamouth DP 
. I think I may have got boost creep once or twice, the stock gauge jumped up past the 8 mark and then went back down to normal, but I think it's just the gauge being a POS.
. I think I may have got boost creep once or twice, the stock gauge jumped up past the 8 mark and then went back down to normal, but I think it's just the gauge being a POS.I'm going with an upgraded CT-26 early next year so i guess i'll just live with it for now. I assume that the shop that will upgrade my turbo will be able to port the WG...
yeh... i'll be getting a 57 trim.... sheet metal intake mani... ported head, exhaust mani in about 2-3 months
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