hey guys. as some of you may know i recently installed a TVS on my car with a 2.7 pulley. Car pulls really well, and isnt even dialed in all the way yet. Still around 11.2 to 11.5 afr at wot. Heres my issue. I installed a 3bar tmap sensor for the lnf in hopes of the stock boost gauge and pcm being able to see the added boost. We installed all of the correct values for the upgraded tmap and got it working nicey. Some people said that the lsj's pcm limit was 21.7lbs of boost. After dialing the car in my tuner and i noticed the pcm was seeing 22.05lbs of boost but that seemed to be the limit. Heres another weird thing under a hard 2 to 3rd gear pull, my stock boost gauge would go past 20, spike then would bounce around like it didnt know what was going on. I installed a mechanical autometer es series gauge with 30psi capabilities hoping i would be able to get an accurate reading of how much boost the car was seeing. Heres whats going on now in the logs we would see boost spike around 24ish then fall off to 22psi, and hold steady all the way to redline. Im beginning to think that somehow the bypass valve is bleeding boost back into the intake and im not seeing the full potential of this blower. What my tuner and i are considering doing next is to try the boost bypass mod while logging the car to see if we see more boost. I figured with the 2.7 on a stock unported head with the exhaust setup i have i should be around at least 24psi. Has anyone else on the TVS with smaller pullies ran into this issue? and what did you guys do to resolve it? thanks in advance

 

bump cmon guys

 

i had my 2.8 on for a while but it was just hitting 20psi... since then ive put on a 2.5 but opened up my exhaust so i should still be around 20psi

 

i have a pretty good free flowing exhaust as well, but doesnt explain while we see it spike around 24 then fall off to 22 gota be the bypass valve

 

wall of txt

 

do what lol?

 

Environmental conditions effect boost. Doubtful you have any boost leak because you're holding plenty of boost all the way through.. That's just a guess though

 

no leaks anywhere, i replaced all the vacuum lines when i did the swap. im also right at sea level. im going to do a log with the bypass mod, if i see more boost than 22lbs then i know its related if not then guess my exhaust flows better than i thought lol

 

Some days I'll boost 10 on the stock pulley m62 and other days i'll have a solid 12..
LOL

 

could be belt slip

 

i would doubt it i ran the 2.7 on my m62 with no issues and i added the zzp spacer for the manifold which was pretty tight its a possibility though im not ruling anything out especially once i do some more testing

 

x2

If it's spiking and falling with a supercharger, the belt is slipping or the bypass is bleeding

 

It's NOT spiking to 24.

Don't ask me how I know.

 

u didnt see the results after the mechanical boost gauge ole man

 

WHo told you the LSJ pcm wont see above 20 PSI? on an MP90 around here there was a guy pushing 25PSI without an issue on his LSJ...

 

The stock boost gauge just freaks after 20 psi and drops down to 0 just get rid of it and run the mechanical one. I wouldn't say you have a boost leak but at what rpm does the boost drop at? And what pulley upgrades are you running to prevent belt slip I highly doubt that is your issue.

 

there was a rumor that people said the pcm wouldnt read past 21.7lbs, even with a 3bar upgrade but weve already prooved that inaccurate as we were seeing 22.05 on the data logs. And i have already installed a mechanical autometer 30psi gauge because the stock one was freaking out

 

Just FYI, the HPT Scanner won't read above ~22psi using a MAP based formula. So, you could have maxed the scanner there too

 

even with the 3 bar? well how else would you be able to see accurate boost without a manual gauge? Im talking as far as hp tuners goes

 

Just get a aftermarket boost guage. With the 2.7 I've seen 24-26PSI. Full exhuast,cooling mods, 50/50 meth,unported head.

 

Even with the 3 bar.. its a limitation of the scanner

The lnfs can use the barometric pressure sensor as a work around.. i don't think we have a usable work around for the lsj..

 

LOl i think i talked with your tuner today i am not sure though. Anyways either of these are your issue with the boost, your bypass valve is opening up, or ure boost solonoid is making it open because its bad which ive seen on quite a few cars, or belt slip... With the issue of the car not seeing anything over 2 lbs, its because the vcm scanne limits. Also we in order to tune the correct fueling at wot with the higher boost you need to use pe and get your ve table working great.. If all is good you should be where you want bro!!

 

Yea James u talked to Joe he is my tuner we will get around it I believe its the bypass valve we will verify Sunday

 

See and that's where I figured I should be that's why I believe as does Joe that something is up with the bypass valve or boost solenoid were gona do the bypass mod Sunday to verify

 

Maybe your boost soleniod is broken. That happened to me.