Question on new WRX drivability
10-28-2003, 12:34 AM
#16
Registered User
Join Date: Jul 2003
Location: 03 WRX Wagon Southern California
Posts: 42
Car Info: 2003 WRB Wagon
The stock turbo won't flow enough air to hold 16 psi all the way to redline, it's too small. That means that your boost will drop as you approach redline. It will probably hold 16 psi thru about 4800-5000 rpm (I'm guesstimating here) and then taper down to as little as 10 psi at redline. YMMV.
"Bucking" sounds like you could be hitting fuel cut, in which case you have boost of 17.5 psi or more. Turn the mbc down to 12 or 13 psi and see if the bucking goes away. If it does, calibrate your boost gauge.
It's also fairly common to melt the hoses that are near your turbo. Sometimes they'll melt on the side you can't see, and only leak under pressure. Use turbo rated hose, and route it away from the turbo itself.
Some more detail on when the bucking occurs would be helpful.
"Bucking" sounds like you could be hitting fuel cut, in which case you have boost of 17.5 psi or more. Turn the mbc down to 12 or 13 psi and see if the bucking goes away. If it does, calibrate your boost gauge.
It's also fairly common to melt the hoses that are near your turbo. Sometimes they'll melt on the side you can't see, and only leak under pressure. Use turbo rated hose, and route it away from the turbo itself.
Some more detail on when the bucking occurs would be helpful.
10-31-2004, 12:44 PM
#17
Registered User
Join Date: Oct 2004
Location: Chandler, AZ
Posts: 10
Originally Posted by 2Stroke
My MY03 wagon had the same hesitation problem when I got it. What fixed it was an improvement to the grounding system.
The theory, in a nutshell, is that the ECU needs VERY accurate voltage readings from the MAP snsor, O2 sensor, etc. to perform at its peak. The conventional wisdom seems to be that the stock grounding setup has enough resistance that voltages are sometimes attenuated before they reach the ECU.
Anyway, the commercial "grounding mod" packages seemed like overkill to me. I changed the battery terminals and added 3 or 4 ground straps which together linked the battery to the intake manifold, engine block, and then to the firewall very near the ECU.
I don't know if all of these were necessary, I'm just reporting what worked for me.
The theory, in a nutshell, is that the ECU needs VERY accurate voltage readings from the MAP snsor, O2 sensor, etc. to perform at its peak. The conventional wisdom seems to be that the stock grounding setup has enough resistance that voltages are sometimes attenuated before they reach the ECU.
Anyway, the commercial "grounding mod" packages seemed like overkill to me. I changed the battery terminals and added 3 or 4 ground straps which together linked the battery to the intake manifold, engine block, and then to the firewall very near the ECU.
I don't know if all of these were necessary, I'm just reporting what worked for me.
11-10-2004, 10:51 PM
#18
Guest
Posts: n/a
My 04 boost and power always seemed to come in chunks! its the nature of the stock tune and stock boost managemtnt. Mine totally dissapeared when I went with prodrives stage 2 pack, and re-flash. Very smooth! The exaust mods and re-flash were the cats meow!
SR
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