I have a question for the mod gurus. I will be installing a JDM STi Uppipe in a couple of weeks in my '03 WRX.

One of my biggest rant about the WRX is the lack of 6th gear. When I'm going about 70mph, I am in constant boost at around 3000-3200 rpms. My car is completely stock right now. Needless to say, my gas mileage at high speeds sucks!

My questions is, if I install the JDM STi Uppipe, it is suppose to lower the turbo spool-up by 500-1000rpms. Therefore, I'm assuming that I will be in boost at a lower speed, say 60-65mph. Is my assumption correct? Will my gas mileage drop even more when I install this uppipe?

With the gas prices sky rocketing, I'm not so sure if I want to do this mod. Do any of you guys know if there's a solution to this?

Thanks in advance.

 

Depends on what your right foot does when it feels the improved spool up from the turbo. Mine went down faster... hense my GM suffered.

I figure that as a general rule of thumb that if you drive the same that due to the increased spool efficiancy you might gain a little GM. All things considered.



-K

 

here in Texas, we have long stretches of highways. Therefore, 70-80mph is constant speed along these highways. That really sucks for me when I'm long driving, not so much for short distances since I will get there faster with the uppipe.

 

my gas mileage went down somewhat when I put the uppipe in. Probably a combination of things, but mostly the fact that it is so much easier to hit boost when you are driving at normal speeds.

 

you pay to play.

at any rate, I do not have the WRX anymore, but when I installed the STi uppipe in it, I actually noticed an increase in mpg. Hope this helps.

 

I've got a GT spec uppipe.

I drive 20 miles to work each way, it's about 75% residentail/city and 25% highway.

I still make 22-24 mpg.

And I've driven from Boston to Chicago 3 times (at 78 mph, at 80 it just starts sucking gas. it seems like 78 was the threshold for my car) and I managed to get 27-29 mpg.

Once you hit the speed you want, just keep the throttle constant. And if you start hearing an increased whine of your turbo or intake, your sucking more fuel.

Also, in non-highway (and non-super #1 racer mode!!) I shift at 2800rpms to keep away from too much boost.

I agree with Silver Arrow about the steady state cruising.

If I don't know what I'm talking about, keep it to yourself : )