I notice when i get on my stock evo, it spikes out my boost gauge at 20 pounds then gose back down to 15psi and stays around 15 could i have a boost leak? or is this normal?

If boost leak how would i find the leak?

 

sounds pretty normal, boost goes up and tapers down when stock, it is supposed to do that.

 

Ok i dident know. Thanks.

I just bought the car so im learning.

 

it actually seems to be tapering a bit too much for a stock evo. it should taper to around 17-18psi only. so it is a good thing to do a boost leak test.

 

well i chopped off the muffler and two of the resinators. so basicly cat back is straight pipe. But how do i do a boost leak test?? somthin i buy?

 

yeah its tapering alil more then average... i bet an mbc and jdm bov will solve that no problem (long as your tuned)

 

I have a XS RFL blow off valve.

 

what is a mbc? and im looking for a tuning device i can just plug into my dash port for under 500 what would you recommend

 

try a laptop then the search button.

 

Stock psi is 19.8psi and then tapers to about 17 around red line. If it is dropping to 15psi there may be another issue. Do a boost leak test, but if it were a boost leak you would not reach the maximum boost level.

Do not just get a boost controller and turn it up and expect things to be fine, they won't. If you are going to get one you will need a tune. However, your first modification should be a turbo back exhaust. I recommend a Hallman manual boost controller when the time comes, other might recommend an electronic boost control solenoid so it depends on what route you want to go.

Also, if you plan on upping the boost through a tune, you will need a different bov. The oem evo 8 bov is plastic and starts leaking once boost goes above the stock level. Simple upgrade, get an oem evo 9 bov (it is metal) and can hold 24-26psi as compared to the oem evo 8 (plastic bov) which can only hold about 20psi. Ditch that Turbo XS RFL bov, I'm pretty sure it is vent to atmosphere and evos do not respond well to VTA bovs. That may be the problem with your drop in boost near red line.

Use the search button. Search "boost leak test" and multiple threads will come up in regards to how to make a boost leak tester and how to perform it. It sounds like you do not have any knowledge about an evo, so please, before doing any further modifications, reserach, read, and read some more information. Read this.. https://www.evolutionm.net/forums/ev...g-dummies.html

 

ok, i will. thanks.

 

wow now i feel dumb. lol well thanks for the new flash on all that. ill try the evo 9 bov and a tune that should take care of the problem. ill do a boost leak test anyways just to make shure.