Boost inconsistent at WOT....any thoughts
 

I have a Vishnu stage 2 wrx. The set-up is great, but lately I've noticed the boost fluctuating between 12-15 psi at WOT in 3rd and 4th gears. Has anyone experienced this? I'm planning on going back to Vishnu as soon as I hear back from them (still holding my breath!).

In another post we were also discussing why my stage 2 fell slightly shy of the 240-250 whp that most VS2's achieve. I got 233 whp, not far off the mark, but short nonetheless.

Well I don't have technical reply, but I got to give you props for posting a picture of your car with your question that rules!

btw: that is a pretty sleeper looking stage 2 WRX!

Re: Boost inconsistent at WOT....any thoughts
 

Not sure what kind of boost controller the Vishnu is using, but it sounds like something is leaking vacume, or the boost controler is confused. Boost should be fairly constant in 3rd from 3500 RPM or lower to at least 5000 RPM I would think.

Shiv at one time mentioned that I may have the wrong tubes for the vf-34. Unfortunately it was a phone message and I really had no idea what he was talking about. By the way, I am clearly mechanically challanged with the technical aspects of the turbo, so I apologize regarding the "tubes"
Any idea what he was talking about or what to look for under the hood. Unfortunately Shiv and crew are almost impossible to get a hold of these days.

thanks

He may have been talking about the lines that run between the boost controller and the wastegate... if the restrictor in there isn't the right size, then the boost controller may not have accurate control over the wastegate, which would result in fluctuations as the ECU trys to keep the boost at one level.

Unfortunately, this is not something that you can tune easily w/o a dyno. If you can't get Vishnu to take care of you, I'd be Nate over at S-Squared could toss it on the dyno and tune it for cheaper than Shiv could. Plus, S-Squared is in Sacramento, so that's only half the drive!

Sounds great do you have their contact info.?

It's at the top of every page! :P :lol:

or email nate directly at nate@ss-ms.com

Thanks, I just got off the phone with Nate. I may be getting a dyno tune on Saturday.

:twisted: Let us know the results!

I was just talking to Nate myself about the vacuum lines on the factory boost solenoid. What Shiv was asking about was, did you keep your stock vacuum boost lines, or did you put the ones from the VF34 on? Shiv has found that on a US WRX, it's better to keep the original stock lines. At this point though, I'd bet you have a knock prone car, or a hypochondriac car. :P

Well. we'll see on Saturday. Nate mentioned replacing the lines with silicone lines. Was he referring to the vacuum lines? If not, should we replace those with stock lines? Or should I just drive my knock prone hypochondriac car into a tree, collect the insurance and buy and STI?

:lol: :lol: :lol: thats one why to look at it :twisted: :lol: :lol:

Well I got back from S-Squared today. Nate and crew if you are reading this...THanks a ton! My car runs so much better. In fact I don't recall it running like this ever. Boost is consistent and strong all the way to 7000 rpm. Nate said it was several things that were causing the issue, so for me to alloborate, I would probably sound like a bafoon. So if Nate wants to detail the issues, feel free. At any rate he spent some time on the dyno and eventually decided a re-flash was necessary. He was clearly correct as the car is amazing compared to what it was this morning. In the end the car pulled 230.4 whp at 7,000 rpm and 213.5'# @ 4750. I am very impressed with the shop and staff. Had a great time talking to all of them about subarus and how to spend money in the future (hopefully soon). Well worth the trip to Sacramento.

Thanks all for the replies and referrals to S-Squared!

Yah we had the really fun filled Dyno day a little while back. :D

It's always great to meet another scooby nut. Good talkign with you today
Very glad to hear another satisfied customer, we never get tired of it, and I'm glad it's stil pulling like a banshee at elevation!
See you for the 2.5 swap ;)


-Aaron