My Jdm Evo7 feels slower than other. So I had my turbo gauge installed today to begin trobleshooting.
I found out my max boost is after 4500rpm. Shouldn't it be 3500rpm. So that's why the car feels slow!

What could cost this? turbo broken? BOV leak? low engine compression? Would an EBC help solve this problem?

 

When I launch from stand still, the turbo will spool up slowly, and then eventually will hit 1.1 bar @ 4500 rpm. I also try to launch from 3000 rpm and the result are similar. I tried in 1st, 2nd, 3rd and 4th.

I did another test on turbo lag. I was on 3rd gear, holding @4000 rpm so that the boost is @ 0 bar. I floored it and the turbo spool up, it took about 1 second before hitting 1.1 bar and then I could really feel the pull. Is this normal for turbo lag?

 

any comment?

 

Most likely problem is you have some type of restriction in the intake or exhaust. Not enough air into the enigine or out of the exhaust and you will spool later in the rpm range.

I don't know all the specifics about the 7 but it's relative.

 

thanks! how do I check the intake/exhaust?

 

Well one easy way to see if you have some type of restriction on the exhaust side is to unbolt the exhaust at the downpipe to cat connection. Take it for a ride and see how it drives and what the boost does.

Then of course the only oher thing is the intake, but all you can really do is make sure the filter (is clean) and the piping all looks good. You might even pop out the filter and put the lid back on the airbox and take it for a quick ride to see how it reacts.

The exhuast is more prone to inhibit the turbine because if there is too much backpressure the exhaust gases will not flow well across the turbine, thus not spinning it up to speed. Just like larger, less restrictive exhaust causes the turbo to spool sooner a restriction will delay it.

If it is a restriction it will be pretty obvious when you eliminate it.

 

BTW.. How many miles are on the car?

 

only few thousand miles when I bought it last month, but you never know what they'd do to the meter...

 

found another problem with the car, not sure it is related to the lack of low end power. My turbo guage reads 0 psi at idel everytime I start the car, after a few minutes it will return to normal(-7 psi).

 

That is usually an indication of where they line was tapped for the boost guage. Chances are they tapped into the fuel pressure regulator lines, but after the solenoid. The line needs to go before the solenoid. Between the solenoid and the intake manifold port. What is happening is the solenoid is off when you first start it. Once it turns the solenoid on you get a reading on the gauge.

If this car is relatively new as you say, I would definitely double chck for boost leakage. Most common problem is the clamp on the BOV hose is not tight enough and leaks.

 

I kinda took a look at the a/c fan. I didnt have enough time to get the front bumper off to really look at it, but, I think the fan's bearing is loose. The fan blades move in and out against the condenser. So I hope I can just repair the fan and not have to buy a new or used one.