I just bought an 03 Evo VIII with a Bushur Racing turbo back and HKS intake. It came with a Defi boost guage, but the guy told me that It was only reading 12 psi and that it needed to be tapped into the right hose.

I looked at the how to on this forum and found the right vacuum hose to tap into and made the necessary changes.

I've never driven a turbo car, so I don' t quite understand the guage......

It's a Defi. When I'm just cruising (not in boost) the guage reads negative 19-20 psi. When I get on the gas the guage goes to 11 psi positive. I don't know if it's negative or positive, but when I'm cruising it's below 0 psi and on the gas it's positive.

Any ideas?? Shouldn't it be reading 19 psi stock?

 

it's not supposed to stay at 19 all the time. haha. usually cruising, you will be at a vacuum. then when you get on the gas, you spool the turbo and hit boost. 19 is what you should reach when you're WOT.

 

WOT and at max boost. Are you saying that it will NEVER go above 11? And yes, it is supposed to be negative when not accelerating.

 

I tried to get it over 11-12, but it didn't look like it was going to go

 

Would this be caused from a vacuum leak? I put all of the hoses back together and double checked everything....

 

Could be...or, like they said...could be the wrong line tapped. I, unfortunately, have not learned enough about the Evo's vacuum system to be able to assist you any further, but one more question - does it seem to keep pulling hard even after the gauge gets to 11psi, or does it feel like it dies off?

 

Is The Car Pulling Hard?or Does It Feel Slugish Do U Have A Afc If Not That Intake Will Drop Your Boost And Pull Timing If Not Tuned

 

what i would do if i was you is check the stock vacuum lines that go to the turbo, wastegate, and the boost control solenoid. just take off your intake and there is a brass thing with two nipples coming out of it that connect to the vacuum hoses i mentioned earlier. the solenoid will be screwed onto the big brass brass colored bracket under the stock intake box. there should be two metal reducers in the vacuum lines. one going to the turbo and the wastegate. you can feel them if you squeeze the lines. if both of them are out this is your problem. with both of those "pills" out you will get very low boost. check this out and let us know what you find. good luck.

 

Kinda sounds like the brass pill was removed. Especially when the last person installed the intake.

 

yes its called vacuum not negative boost just stating the fact for yellowman

 

just so you know, you do not have a boost leak or any other problem with the car except that if you have a boost controler, it is not hooked up right, and if you dont have a boost controler and you are only getting 10-12 psi then your factory boost solenoid has a problem. You should be spiking at 19psi and holding around 15psi stock, because the boost solenoid tricks the car into running more boost. The factory wastegate setting is 10-12 psi wich is what you are getting. This means that your factory boost solenoid is probably unhooked which would put the car to the factroy wastgate setting of 10-12 psi. I doubt that you are hooked up to the wrong vacuum line and i doubt that you have a boost leak. Try looking to see if the boost solenoid is unhooked, it is the harness under the air intake. I gaurantee that has something to do with your problem.

 

yep

 

how many threads do you need for the same answer?


https://www.evolutionm.net/forums/sh...65#post1845165

 

Here is everything you could ever need to know about the setup:
https://www.evolutionm.net/forums/sh...ad.php?t=98114