RedFC

My buddy has an 05' Evo8, apexi 3" TBE with test pipe, and he's got the expected Service Engine Soon light....Whenever he opens up past 5500rpm in any gear, it feels like the boost is gone, it kind of just gives up....accelerates really slow if any past that.... feels and spools normal before it just lays out, talked to multipe performance shops and am told that the rear 02 sensor has no effect on driveability

Could this be the wastegate or something else? Any clues, ideas, anything?

IDRINKV8

iTrader: (27)

if he is untuned and has his boost turned up he needs to get a reflash because he is hitting boost cut from a lack of fuel.

occultworks

iTrader: (6)

The boost will naturally taper, so it's normal for it to feel like it loses power up top.

There may be boost cut as well. Does it feel like you hit a brick wall after 5500rpms?

RedFC

I havent actually had a chance to ride in it yet, but from the way he describes, it sounds like its just hitting a wall. I understand that boost naturally drops, but this is a little more extreme.

He also mentioned to me that it will work fine sometimes, then somedays, it will just lose all power past 5500rpm. I keep thinking that something is messed up with his wastegate or something. I had a similar problem a while back when an IC clamp came off on my rx7, but that doesnt sound like this. He is kind of new to cars, so its hard for him to describe, but it sounds like it is just opening up or something, and venting all of his boost. I know there is no way his turbo is already crapping out, and he is also running the stock boost, with no ebc or mbc.

This car is pretty much stock, and starting giving him these problems after installing the turbo-back. Give me anything that it could possibly be, the more suggestions, the better. I'll have to take a look at it soon to see if I can figure it out, or give yall some more details.