I mostly know all of you here on Ecuflash section and have help me alot with my journey on my Evo8. So here's a question:
I was set up for 25psi on the street on regular basis. But last Friday I went to the track to test my new IC set up. I did a 12.2 run wich is good. But my problem is the turbo wont boost higher than 20psi. It will boost 20 on 1st gear then drops at 17psi and 18psi all the way to 4th gear. Is this normal for this stock turbo? I'm running 2.5 LICP, 12x32x4 IC, 3" UICP. So I think the turbo is not efficient enough to hold 25psi of boost on a constant load. Does anybody have the same experience with me on Evo8 turbo? How about the Evo 9? Since it has a bigger compressor housing, does it hold the boost better than Evo 8 turbo?

I hope this question is ok in this section? I just don't know anybodyelse outside this thread. Thanks in advance.

 

A better IC could possibly transfer heat better, cooling down your intake charge (and raising its density). I could maybe see a 0.5 or 1.0 psi drop after installing an IC kit, but not a 7 psi drop, the change in air temp would not be that extreme. My recommendation is to check for boost leaks. Search for threads on it, there is a easy DIY one from like home depot for like 10 bucks. Ive even used it with a bicycle pump to pressurize my intake track, it takes a while. What are you using for boost control?

 

I'm using the hallman boost controller. And there's no leak at all on my pipings. Ive pump 30psi from my compressor at the turbo inlet and its all clear. My boost tapered was already happening even when I had the stock IC set up. It would boost 25 then drop to18 at 7k rpm. I've also had this same problem before with my old Turboxs IC and injen piping set up. I also modified my wastegate and added the heavier spring with it. The car runs strong but I just think I can do better if I can hold the boost. So all in all, this is my 3rd intercooler set up and still does the same thing.
Anyways I just got my hands on a ATP gt3076r turbo set up last night and I might try it on. But all I really want is a 11 sec run from the stock turbo and I think I might make it if I can hold the boost. Then I might just sell the ATP turbo. I just like how the stock turbo responses.
Anyone else has another opinion? Thanks

 

did mph in the quarter change from pre IC install and post IC install?

If mph increased then the IC worked and you have no issues.
if it stayed the same then you have no issues.
if it decreased then your boost problem is most likely legitimate.

 

My IC setup is 2.5" piping with 12x24x3 FMIC. I boost 25 then it tapers to 23 and this is on a stock 8 turbo with 10.5 hotside. If you have no boost leaks, I would check the MBC or possibly the WGA that you messed with. Just my .02

 

Look at your street logs of boost above 4500-5000rpm, what is it? My guess is that when you are at the track you RPM's are always in the 4500+ range and if you compare the track logs to the street logs the boost is similiar.

Try tightening the waste gate rod a bit to put more preload on the wastegate. This may get you to hold 1-2psi more at the topend and get you to 20psi max taper.

 

Its normal for your boost to drop some with a larger intercooler, you will also see less boost at the track because you are going through the gears.

 

1. My wastegate is backed up all the way and I've installed a heavier spring as well.

2. As far as my log, If you would ckeck one of my thread. I was having a problem with the load value after I installed my IC set up. Before, my load was sync with my boost. Meaning when I boost 25psi my log reads around 280load. But know, when I boost 25psi my log reads 340load. And it was like320 at the track since it wasn't boosting higher than 20psi.

3. I'm gonna try a different boost controller. Since I had the same problem before even from my recent IC set up, then maybe my boost controller is messed up.

4. I'm also gonna compare my previous time sheet and see if I improved my trap speed.

Thanks for all your advice.

 

If you're > 300 load and the boost gauge shows 20psi, either the gauge is broken or, more likely, you have a sizable boost leak. The load value comes from how hard the turbo is working, and the boost gauge should be showing how much is making it into the engine... if there's a big discrepancy, 9 times out of 10 it's because of a leak, the other time it's because of a screwed up MAF.

Last year I had a small boost leak, and the top of 4th gear would be showing 280-290 load and 25psi... this year, after fixing the leak, load is down to 270-280 and boost is up to 27-28.

 

I know that's what everybody recomended and what I thout as well. But I've done all the test from my other thread and there's no leak at all. It could be the maf sensor. I wish there's somebody local that can lend me the maf so I can see.