EVO IX boost issues?
Dec 21, 2006, 04:47 PM
#1
EVO IX boost issues?
Well ever since I went back to stock(problems with the police) I'm not hitting normal peak boost anymore. The turbo still hits full boost at around 3500 rpm but all I see is a quick spike to 17-18 psi then it drops down to 16 psi and holds untill redline were it tappers down to 14 psi. It feels like I'm still making power cause the car still flys when I run it through the gears but 16 ish psi seems too low. I reset the ecu and checked for leaks and found nothing. Any ideas before I take it to the shop?
Dec 21, 2006, 05:23 PM
#5
When you went back to your stock exhaust you wound up with
a restriction(stock exhaust)you dont make as high a boost. When
my high flow cat fell apart a peace got wedge side ways in my
exhaust I could not make over 12psi and I run 28psi.Like
was said earlier you are going to need to run a boost controler.
Be careful with the restriction more boost higher egt more knock
higher cylinder presures.
a restriction(stock exhaust)you dont make as high a boost. When
my high flow cat fell apart a peace got wedge side ways in my
exhaust I could not make over 12psi and I run 28psi.Like
was said earlier you are going to need to run a boost controler.
Be careful with the restriction more boost higher egt more knock
higher cylinder presures.
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Dec 22, 2006, 07:57 AM
#8
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Ive seen a couple stock ix on the dyno and that sounds about right for boost. Ive seen 19-20 psi peak every know and then but tappers at redline to around 16psi so you are about right on there. I say you check for leaks or just get a manual boost controller set it to 20 and call it a day.
Dec 22, 2006, 10:35 AM
#9
I know that the boost tappering off near redline is normal but the 15-16 peak psi seems odd to me. When I first got the car I installed the defi gauge and I would see a spike to 20 psi and hold 18ish psi till redline where it drops to 15ish psi. So I know for sure I'm down a few psi from when it was new. My friend is going to come by and do a pressure test tonight so we'll see what happens.
Dec 22, 2006, 11:20 AM
#10
I know that the boost tappering off near redline is normal but the 15-16 peak psi seems odd to me. When I first got the car I installed the defi gauge and I would see a spike to 20 psi and hold 18ish psi till redline where it drops to 15ish psi. So I know for sure I'm down a few psi from when it was new. My friend is going to come by and do a pressure test tonight so we'll see what happens.
Second, I really doubt that you were holding to 18 psi to redline on a stock 9. Stock Evo 8s usually taper to 15-16 psi by redline as logged by a MAP sensor. I read that 9s are even worse when it comes to taper due to mivec.
If you really want to know what your boost is, then the best approach is to log it with a MAP sensor. Most non-MAP boost gauges are off to begin with and eyeballing them when your going WOT adds more error to the equation.
Dec 22, 2006, 11:36 AM
#11
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Ggrey,
I think Im experiencing a similar situation to you, although I never messed with any of the boost lines or anything else for that matter since my car is completely stock and untouched. It seems as though my 9 is either leaking boost or pulling timing. I am already on a new full tank, so the bad gas theory goes out the door. I don't have a boost guage, but it should be on my doorstep next week since I just ordered my Zeitronix.
Its getting progressively slower. If I do a test pull with my brother's MS3, where in the past I would pull in every gear, now he is actually pulling ahead, and it is getting noticably worst.
Im going to be checking for boost leaks tonight as well!
I think Im experiencing a similar situation to you, although I never messed with any of the boost lines or anything else for that matter since my car is completely stock and untouched. It seems as though my 9 is either leaking boost or pulling timing. I am already on a new full tank, so the bad gas theory goes out the door. I don't have a boost guage, but it should be on my doorstep next week since I just ordered my Zeitronix.
Its getting progressively slower. If I do a test pull with my brother's MS3, where in the past I would pull in every gear, now he is actually pulling ahead, and it is getting noticably worst.
Im going to be checking for boost leaks tonight as well!
Dec 22, 2006, 11:48 AM
#12
Some gauges tend to be off by about 1-1.5 psi. I had a Defi D and it used to read 23-24 psi peak. When I logged the boost with a MAP sensor it was 21.5-22 psi peak.
Second, I really doubt that you were holding to 18 psi to redline on a stock 9. Stock Evo 8s usually taper to 15-16 psi by redline as logged by a MAP sensor. I read that 9s are even worse when it comes to taper due to mivec.
If you really want to know what your boost is, then the best approach is to log it with a MAP sensor. Most non-MAP boost gauges are off to begin with and eyeballing them when your going WOT adds more error to the equation.
Second, I really doubt that you were holding to 18 psi to redline on a stock 9. Stock Evo 8s usually taper to 15-16 psi by redline as logged by a MAP sensor. I read that 9s are even worse when it comes to taper due to mivec.
If you really want to know what your boost is, then the best approach is to log it with a MAP sensor. Most non-MAP boost gauges are off to begin with and eyeballing them when your going WOT adds more error to the equation.
Dec 22, 2006, 01:16 PM
#14
I asked a couple of local IX owners and they told me 17-18 psi is normal for peak boost on Cali 91 craptane. They told me not to worry if I'm still making the power. I'm still able to pull on my friends stage 2 wrx so I guess I'm ok but I'm still going to do a pressure test tonight.
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