Installed a Autometer sport comp boost gauge (the same as the on buschur racing's site) and I peak at 14 psi WOT in any gear. I did a seach on getting low boost and I tried everything suggested. I tightened every clamp in sight, I removed the airbox to get to some of them. I checked the boost line leading to the boost solenoid and at first it was zip tied to the the intake tube. I cut the zip tie since it was pinching the boost line, this did not help much maybe gave me half a psi. I'm still nowhere near 19psi peak. What else could be causing this problem? The car is stock except for the boost gauge. The boost gauge is tapped into the same location as the pictures in this thread: https://www.evolutionm.net/forums/sh...threadid=36529

I don't want to bring my car to the dealer because their mechanics are a bunch of monkeys and they will probably keep my car for a long time. I'll try a different boost gauge next week. In the meantime I'm open to suggestions, thanks.

 

Try checking the nylon lines going to the boost guage. It might be kinked. you know it comes all rolled up, and when you try to straighten it, it tends to kink.

 

Just checked nylon hose and no kinks. It did shrink a little just on the part that it connect on the gauge due to tightening the nut around it but I think that's normal. btw, vacuum reads a little above 20hg at idle, is that what everyone else is reading?

 

test your gauge... the first place to go is always to verify that you indeed have a problem. If your boost is as low as you say it is your car's performance should relfect it, does it?

 

How do I test the gauge?

My EVO is the only EVO I've driven so I don't have anything to compare it's performance to.

 

I was in the same situation with my stock 280hp Evo7. I thought the boost should be 1.3bar/19psi but I am getting only 1.0bar/14.5psi. After talking to many Evo expert here in Hong Kong, I am convinced that 14.5psi is normal for the stock car. I don't know why many people say the stock Evo8 is 19psi, when mine is only 14.5psi and produce 280hp.

 

It should peak at least 18PSI. Espically in 4th and 5th gear.
Then it comes down to around 15 or 16. Your vacume seems to be about right, so that should mean its sealed up pretty well. I guess there could still be a leak under boost.
Like someone eles said switch the boost guage out and go from there. Autometers are notorious for being up to 3 PSI innacurate.

Come to think of it you said your vacume was around 20 PSI. Most I've seen was right around 16 with the A/C off. So if your reading ~20 PSI vacume, your guage could be off in that direction. Meaning your boost would be around 4 PSI low. Does the guage center on 0 when the car is off?

 

yup others have said their vacuum at idle is 15-17 so I think my gauge might be off. As far as where it centers w/ the car turned off, there's a box at zero on the gauge, mine centers on the bottom of the box. See this pic on buschur's site:
http://www.buschurracing.com/EVO8_BoostGauge_Large.jpg
Mine does NOT center where his does but I don't know if it is normal to center anywhere on the box.

 

Mine centers in the box.