350Z400rwhp

iTrader: (4)

Last night I was getting on my car and it seemed to lose boost on the high end (5500+ rpm) of first and second gear (didn't try to go to 3rd). I though my meth was running dry and maybe my utec was pulling timing so I topped off my meth reservoir. Drove it after that and then it seemed to pull all the way to redline so I figured the problem was fixed. It seemed to be fine today but still seemed slow on the top end from time to time. Took it out after work and it was fine, just decided to take her out for a midnight drive and the problem is back. Seems to pull hard and right about 5500 rpm the boost drops off to about 5 psi and almost sounds like excess air is being released out of my bypass valve but not sure. For some reason youtube is taking some time to get my video processed but I will put them up here asap. Any ideas? I'm sure the videos will help to explain more.

thom000001

without seeing vid I'll take a shot in the dark....first off, belt slip???

350Z400rwhp

iTrader: (4)

makes sense, I do have the gtm pulley upgrade and just a 3.12 pulley though.

350Z400rwhp

iTrader: (4)

Ok so here is the first run (2nd gear) only makes it to about 5 psi and all the sudden it sounds like air is bleeding off rapidly so I let off.
http://www.youtube.com/watch?v=w3Z0fhUPvcU

The second run is pulls longer and boost hight but does the same thing and then I let off.
http://www.youtube.com/watch?v=i668-MEb5WM

Nexx

iTrader: (41)

belt slip bryan, definately belt slip. the mod does nothing if your belt loosens up too much. two days after my first dyno at 8 psi on my original 3.12, my belt loosened up to where i was getting 2psi. you hear the air because you are losing boost and the bypass opens up. easy fix.

350Z400rwhp

iTrader: (4)

makes sense, I have a belt that I feel is too lose. I have my tensioner all the way tight but it still squeels for a good 30 seconds or more on the first start up of the day or when it's cold

Nexx

iTrader: (41)

yep, time to make a trip to napa, get a belt thats 1/2" inch shorter than what you have now. if your car squeels in the morning, its not tight enough.

350Z400rwhp

iTrader: (4)

Sweet I hope that's what it is, this loose belt issue has been my only problem (car makes weird pulley noises until engine gets really hot and belt squeeling on start up and all) and I have been meaning to replace it, I just figured a looser belt was ok with there being less stress on the bearings.

Audible Mayhem

iTrader: (48)

yeah, we always run then .5 inches shorter on every setup than what they give you. also, the cheapest belt you can find will work better. we have tried them all.

one more thing, check the oring inside the bypass valve. we have seen a few come out and it will blow boost by. very easy fix...

350Z400rwhp

iTrader: (4)

I was thinking it may be the bypass valve too. My belt is def too loose so I will start by replacing that. If that doesn't fix it I'm going to check that bypass valve next.

str8dum1

iTrader: (11)

make sure if you do check the o-ring, dont push the plunger on the BPV very much. so easy to f up the valving. know from experience, as my o-ring came off and i pushed on the plunger too far and had to get a new BPV from vortech.

JonnyC

iTrader: (19)

Before I installed my kit it wanted to open up the bypass valve to make sure everything was good. But man, I could not get the thing apart of the life of me. I bent like 3 ring clamp tools trying to get that thing off. I guess I should stop buying cheap Chinese crap from Harbor Freight though.

350Z400rwhp

iTrader: (4)

If it comes to looking at the bypass valve I'm going to be asking you guys before I touch it. I have read many threads talking about how easily the bypass valved can be f-ed up when taken out and or taken apart.

booger

iTrader: (6)

I hear they say not to push the valve open on the Vortech BOV , but Ive pushed in on mine a bunch of times . Had it apart several times and put a softer spring in it . Still worked great and held to over 20psi

Nexx

iTrader: (41)

any updates bryan?

350Z400rwhp

iTrader: (4)

Eh I did buy the belt, it was raining yesterday, today I had to work all day and I went out tonight. I am going golfing tomorrow so I plan on putting the belt on when I get home from that. This crappy weather is very un-motivating.

Quamen

iTrader: (14)

Same here. If you take one apart it is no different than any normal bypass valve and unless you tear the diaphragm or assemble incorrect it should work.

350Z400rwhp

iTrader: (4)

Well I got the new belt in and it fits perfect. I think the one I originally bought was smaller even though it had the same model number. With the tensioner all the way in I was able to put this new belt on and at about 3/4ths the tensioner had put enough tension on the belt to where it felt nice and tight. I started the car and no squeeling! yay! I took off in second gear and it seemed to do the same thing so of course I got depressed but that was the only time it hiccuped all night. Only time will tell but for now it seems the problem was solved, not to mention no more crappy pulley sounds from my engine compartment for the first 15 minutes until it heats up. Thanks for the input everyone!

JonnyC

iTrader: (19)

You'll probably have to adjust it one more time once the belt stretches a bit, but I'm glad that things are working better.

OT, but looking to get your idle raised? I'm thinking about buying the Cipher software so I can do it and "rent" it to people who need to do the same.

350Z400rwhp

iTrader: (4)

Hey let me know on that, I could use a 200 rpm bump. I'm pretty happy though as my supercharger is pretty quiet at idle. Hey Johnny did you pull your filter and look at things yet? Good news, Bad news?