What do you mean you are seeing '1.2 bar for a bit'? What RPM?

 

markski told you your logs are okay and first adjust your wastegates right.....now you do it and it is not better...but k24/20 with a stock exhaust have to much backpressure..you will never get more boost

change your exhaust ....and you will be right

 

Stock exhaust? There's your flow restriction. Your turbine sides can't breathe.
Winnigt2 might have hit the nail on the head there.

 

^^^ This was suggested in his other thread, but it got derailed by a suggested turbo problem with the 24/20's he bought.


https://www.6speedonline.com/forums/...king-help.html


I didn't realize that he had stock exhaust (modified or otherwise), Could very well be the problem, as well as plugged cats. Could have been the problem all along as the OP seems to feel he may have had this problem before hand. I might remove the exhaust and go for a quick trip down the street once, or get some straight pipes to test with.

 

Plugged cats can restrict/kill boost. Know a guy who couldn't hit his 1.5 bar target boost and was only hitting 1 bar. Put some straight pipes in and boom....1.5 bar all day.

 

I have seen cars that wouldn't start because of plugged cats= would be nice/sad if that's all it was.

 

i believe he already checked the cats.

 

Hey guys, cats are fine. I bought a tool to check the pressure before the cats and it didn't even register on the gauge which starts at 0.5psi.

I doubt very much it is the stock exhaust system as a stock car will over boost if you disable the wastegate actuators in a heartbeat. My exhaust is modified whic helps a bit with flow (but yea it won't match the flow of an aftermarket exhaust).

I also ran the car without the cat-back on and it didn't make a difference. Now at the time I also had the MAF sensor disconnected and it ran very sluggish on top end since it was dumping fuel so not sure if that would affect things but it still ran about the 1bar that it always does.

 

There must be a reason that all the major tuners and mod shops recommend an exhaust and a tune as their first mod for these cars.

 

It will make 1.2 bar for a second right before redline in 3rd gear.

 

https://www.6speedonline.com/forums/...kpressure.html
Says here stock exhaust has over 5psi back pressure, maybe your tool wasn't accurate.

 

You know, 1.2bar is pretty close to 1.3bar
Might be worth a try to drop your exhaust or cats now that you've sorted out the other issues
Still doesn't explain your lack of over boost with deactivated wastegates though.

 

That's maximum back pressure. When testing you do so at idle. Anything over 1.5psi at idle means there is an issue on most cars. Well bellow 1psi at idle is the norm.

 

Yea but the turbos are working their butts off to produce that 1.2bar. Basically they are way out of their efficiency range and doing everything they can to muster up that 1.2 bar right at redline.

 

I don't believe your turbos are being maxed out . Look at your last log. Your air flow stays the same at 1350 kg/hr from 5000rpm to 7000rpm. That's not a high flow rate for these turbos.
This would be the range when high back pressure would restrict your turbine speed.
Again, I'm no expert so I might be wrong.