Jump to content
SAU Community

Recommended Posts

Hi all i seem to have a boost creep problem after installing a high flowing exhaust system (jjr split dump, 3inch catco and power extreme II cat back), it boosts up to about 14 psi as the revs rise up (I even manually tied the flap all the way open). After doing a search it seems maybe the turbo cant flow enough through the wastegate housing or dump pipe any ideas? Will a bellmouthdump pipe help me? can i dremel out the wastegate housing a bit maybe?

My car is a s1 r33 with r34 intercooler and pod that is the limit of mods. Any help or ides welcome.

cheers.

added brand new hks actuator today but, its overboosing when the gate is manually tied totally open the absolute min boost is 14+ psi problem seemed to start after installing high flow cat. Ill try dropping the exhaust tomorrow, going to try friends bellmouth too. The exhaust is brand new and the car makes very good power with it way more than the stock system. Is it hard to increase the wastegate size can it be done just using a dremel? If i can get it down to 10 psi i will be happy. thanks for the replys

Its definitely not 'normal' for a stock turbo to boost creep.

My first point of call would be the dump pipe. The dump is what directly has an affect on the boost control in a closed system.

Maybe its just a bad one; possibly the point of merge for the wastegate split is a tad messy (not well matched) inside that restricts wastegate flow.

maybe I should dremel the dump pipe out a bit first then (the fitting was average with respect to the lining up of the flange bolts and the lining up of the waste gate pipe to the flange hole, I didn't think it would of had a huge effect at the time, soon see though) Im not really keen on taking to the turbo with the dremel. I just want to dremel something now!!

It is not an exhaust freeness problem.

You either have a problem with vac hose plumbing or with your actuator.

There is absolutely no need to dremel out anything.

I've never had any problems, even using highflowed turbos pumping out 20+ psi. Standard size hole is fine.

Ok I definitely wont dremel the turbo then. The pipe and actuator are brand new as that is what i thought the problem was too but still overboosted so i disconnected the actuator arm from the wastegate flap and put a zip tie on the flap so that it was all the way open to me this says that i should make very little boost but when I took it for a drive it still had no problem boosting to 13 psi but not till high up in the revrange. Thanks for all the input.

It is not an exhaust freeness problem.

You either have a problem with vac hose plumbing or with your actuator.

There is absolutely no need to dremel out anything.

I've never had any problems, even using highflowed turbos pumping out 20+ psi. Standard size hole is fine.

Its deifnitely not a vac hose/actuator problem. As per his first post he has tied the wastegate wide open and it still boost creeps.

I would definitely be looking at the wastegate dump to turbine dump merge point.

Pic attached.

post-382-1185580689_thumb.jpg

Ok the dump is off, too me it looks like the wastegate is exiting straight onto the flange maybe (the blackened part) oh and the best part a bolt snapped of in the turbo and my o2 sensor is stuck in the pipe.

cheers

post-36364-1185581700_thumb.jpg

Edited by SevenAngryPenguins

Another thing to check.

With the dump on does the wastegate foul with the dump when attempting to open it fully? Possibly the dump is preventing the flap from opening fully? Unlikely but worth checking while its all off.

Compare the opening angle to that of the std dump if you still have it.

I always throw some antisieze on the thread of the o2 sensor. Supercheap have little satchels for around $1 each.

mine is same 13psi what ever i do ,it wont boost lower :P .my dump is a single track but big size.autos are 5psi standard but manuals are 7.2 standard boost without intercooler /exhaust.

ive tried alot of thing but to no luck yet

the 2 things i would look at are:

1, when the wastegate is open is the air still able to flow past it. the wastegate may be opening without fouling, but it may be blocking the path of the air through the wastegate pipe of the dump pipe.

2, chech where the wastegate pipe blends back into the dump pipe. the one i had the pipe was welded off to the side of the hole. it didn't leak but when you looked at it from the inside half of the hole was covered. so i got the die grinder out and opened the hole up. i had to take a section out about 4cm x 0.7cm.

Drop the exhaust, just before the cat, and see if the creep goes away.

If the creep goes, something in the exhaust maybe restricting flow. Check also for any air leaks to the actuator.

itrs the other way around dude.

your wastegate isnt flowing enough. perhaps try putting the standard dump pipe back on. that will solve it.

Its deifnitely not a vac hose/actuator problem. As per his first post he has tied the wastegate wide open and it still boost creeps.

I would definitely be looking at the wastegate dump to turbine dump merge point.

Pic attached.

Oops, silly me. I didn't read the first post carefully. Just thoguht it was the usual wrong plumbing/faulty actuator

ok this is what im thinking that the wastegate flap was fouling just a little as it feels different to move now than when i did when the dump pipe was on. I don't have the old dump to compare too but when i place the dump pipe gasket over the pipe the top hole (waste hole) doesn't look like its even close to lining up with the turbo waste gate. I'm not sure I think i will just buy a bellmouth dump pipe and see how it goes after i pull the turbo off to get that damn bolt out!! Maybe should highflow it while its off hmmm......

post-36364-1185602642_thumb.jpg

Edited by SevenAngryPenguins

Hi Chris,

The waste gate is fouling on the bracket that holds the turbo heat shield or it is hitting the side of the flange.I had this very same problem but due to work commitments had no time to really look at it for a year.When I did look I found the original dump flange was a lot thicker than the stainless with separate waste gate.So the waste gate arm was hitting the bracket holding the heat shield stopping it from opening more than half way.I could wind the boost up to 14lbs but any more and boost would go crazy fluttering up and down.Bear in mind my turbo was high flowed and would operate better with a bigger exhaust wheel but with a standard turbo and hence smaller turbine wheel you would get the same thing happening at a lower boost setting.You only have to take the cover off and take off the circlip with a fine screw driver then pull the actuator rod to take some pressure off the lever and lift it off.Now that the wastegate arm is free to move it should be able to swing around to face directly over the dump pipe at a right angle to the flange.If not,well,there is your problem.

yeah my arm hits on the heat shield and then it seemed to drop down into a slot and to move it back it had to be lifted up (has bit of up and down movement) this is stock setup though..... how far does the actuator need to travel? my flap operates correctly with the pipe removed not sure about when its on ill check when the turbo is off, should i modify my heat shield did this solve your problem?

Edited by SevenAngryPenguins

Hey i got similar issues i think i got an xforce turbo back 3inch with hi-flow cat and FMIC and airfilter no boost controller gettin a reading of 12psi and car seems to not wanna rev past 5000rpm...nethoughts?

Because the flange is thinner the bracket is closer so just put 2-3 thin washers in between the flange and bracket to space it out a bit. Only has to be the difference between the old flange and new,so only a couple of mil.

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now


  • Similar Content

  • Latest Posts

    • Update 3: Hi all It's been a while. Quite a lot of things happened in the meantime, among other things the car is (almost) back together and ready to be started again. Things that I fixed or changed: Full turbo removal, fitting back the OEM turbo oil hardlines. Had to do quite a bit of research and parts shopping to get every last piece that I need and make it work with the GT2860 turbos, but it does work and is not hard to do. Proves that the previous owner(s) just did not want to. While I was there I set the preload for the wastegates to 0,9bar to hopefully make it easier for the tuner to hit the 370hp I need for the legal inspections that will follow later on. Boost can always go up if necessary. Fitted a AN10 line from the catch can to the intake hose to make the catchcan and hopefully the cam covers a slight vacuum to have less restrictive oil returns from the head and not have mud build up as harshly in the lines and catch can. Removed the entire front interior just shy of the dashboard itself to clean up some of the absolutely horrendous wiring, (hopefully) fix the bumpy tacho and put in LED bulbs while I was there. Also put in bulbs where there was none before, like the airbag one. I also used that chance to remove the LED rpm gauge on the steering column, which was also wired in absolute horror show fashion. Moved the 4in1 Prosport gauge from sitting in front of the OEM oil pressure gauge to the center console vents, I used a 3D printed vent piece to hold that gauge there. The HKB steering wheel boss was likely on incorrectly as I sometimes noticed the indicator reset being uneven for left vs. right. In the meantime also installed an airbag delete resistor, as one should. Installed Cube Speed premium short shifter. Feels pretty nice, hope it'll work great too when I actually get to drive. Also put on a fancy Dragon Ball shift knob, cause why not. My buddy was kind enough to weld the rust hole in the back, it was basically rusted through in the lowermost corner of the passenger side trunk area where the wheel arch, trunk panel and rear quarter all meet. Obviously there is still a lot of crustiness in various areas but as long as it's not rusted out I'll just treat and isolate the corrosion and pretend it's not there. Also had to put down a new ground wire for the rear subframe as the original one was BARELY there. Probably a bit controversial depending on who you ask about this... but I ended up just covering the crack in the side of the engine block, the one above the oil feed, with JB Weld. I used a generous amount and roughed up the whole area with a Dremel before, so I hope this will hold the coolant where it should be for the foreseeable future. Did a cam cover gasket job as the half moons were a bit leaky, and there too one could see the people who worked on this car before me were absolute tools. The same half moons were probably used like 3 times without even cleaning the old RTV off. Dremeled out the inside of the flange where the turbine housing mates onto the exhaust manifolds so the diameter matches, as the OEM exhaust manifolds are even narrower than the turbine housings as we all know. Even if this doesn't do much, I had them out anyways, so can't harm. Ideally one would port-match both the turbo and the manifold to the gasket size but I really didn't feel up to disassembling the turbine housings. Wrapped turbo outlet dumps in heat wrap band. Will do the frontpipe again as well as now the oil leak which promted me to tear apart half the engine in the first place is hopefully fixed. Fitted an ATI super damper to get rid of the worn old harmonic balancer. Surely one of the easiest and most worth to do mods. But torquing that ARP bolt to spec was a bitch without being able to lock the flywheel. Did some minor adjustments in the ECU tables to change some things I didn't like, like the launch control that was ALWAYS active. Treated rusty spots and surface corrosion on places I could get to and on many spots under the car, not pretty or ideal but good enough for now. Removed the N1 rear spats and the carbon surrounding for the tailpipe to put them back on with new adhesive as the old one was lifting in many spots, not pretty. Took out the passenger rear lamp housing... what do you know. Amateur work screwed me again here as they were glued in hard and removing it took a lot of force, so I broke one of the housing bolts off. And when removing the adhesive from the chassis the paint came right off too. Thankfully all the damaged area won't be visible later, but whoever did the very limited bodywork on this car needs to have their limbs chopped off piece by piece.   Quite a list if I do say so myself, but a lot of time was spent just discovering new shit that is wrong with the car and finding a solution or parts to fix it. My last problem that I now have the headache of dealing with is that the exhaust studs on the turbo outlets are M10x1.25 threaded, but the previous owner already put on regular M10 nuts so the threads are... weird. I only found this out the hard way. So now I will just try if I can in any way fit the front pipe regardless, if not I'll have to redo the studs with the turbos installed. Lesson learned for the future: Redo ALL studs you put your hands on, especially if they are old and the previous owners were inept maniacs. Thanks for reading if you did, will update when the engine runs again. Hope nothing breaks or leaks and I can do a test drive.
    • No those pads are DBA too  but they have colors too. I look at the and imo the green "street" are the best.
    • I’m not sure what happened I told them about sonic tunes free OTS tune and the next the I know .. I was booted..   To funny 
    • Yea - I mean I've seen my fuel pump which is decades old and uh, while I'm not saying this with real knowledge... but I sure get the ick at using anything in the fuel system that produced the state of that pump. Many years ago I went through multiple pumps (and strainers) before I dropped the tank to clean it out with extreme violence. I'm talking the car would do maybe 50km before coming to a halt, which resulted in me cleaning out the filter with some brake cleaner and going on my way. None of my stuff ever looked like what came out of your fuel tank. I don't think I'd be happy with it unless every single component was replaced (or at least checked/cleaned/confirmed to be clean here).
    • I'm not going to recommend an EBC pad. I don't like them. Just about anything else would suit me better. I've been using Intima pads for a while now.
×
×
  • Create New...