I just installed my Stewart Warner boost gauge today. I dont know if the boost gauge is broken or its my car but when i am at WOT the gauge would spike to 20psi and then drop back down and stay at 15-16psi. I checked all my connections for leaks and can not find any. Another member on the board has the same problem and we cannot figure this out. Any help would be appreciated. thanks

btw the gauge reads 19-20 psi vaccume.

 

get an MBC and see how it goes... that sounds like the stock ecu at work

 

thats just the normal taper 19-20 tapering to about 16 and if you're talking about idling at 19-20 vac thats about right too. don't worry warrtalon will find this and let you know it cool

 

It sucks, but it's normal.

 

I have the same gauge and it reads exactly the same despite having an MBC as well....

 

but this is in the 4500-6000 rpm range....i didnt think tapering happened until close to redline.

 

Yea all of them will do that if you dont have a boost controller other than the stock solenoid. And even then they'll still do it just not as bad. Its simply your turbo not being able to keep up at the high rpms combined with the ecu tapering it anyway to keep it safer at higher rpms. Nothin to worry about. I miss the days of 19 vaccuum. Wait till you do cams. i get 11 now(revolvers)

 

sounds like it is reading right... if you are tapering that much with a MBC something is not happy, should check it out... what type of MBC ... did you lube it before installing it ?

 

i always thought stock evo's boost 19psi-20psi. 15psi seems very low to me and i am always reading people boosting 20psi and tapering down to 19psi.

look,

 

I used to have a 05 VIII and now have a IX. I used the same boost gauge on both and the IX seems like it likes to taper more and some times I have seen it taper as low as 15lbs.

Find a long road, get in fourth gear @ 2500RPM, got WOT and you'll probably see the boost curve (taper) you want.

 

apparently all IXs do this. The ecu's stock boost control is so erratic i thought it was broken at first.

 

Well thats relieving to hear. I was beginning to wonder if it was normal, but I'm going to check for leaks sometime this week. Even with having an MBC, I still taper down 16psi by redline.

Aside from pressurizing the system, is there any other way to know you have leaks? I mean, I recently took it to a dyno and it made good power (300whp/310wtq and on stock exhaust) and thats where it was still tapering down to 16psi...

 

get a good electonic boost controller and you boost tapering issues will be gone.

Got to love the avcr...