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Discussion Starter #1
I'm considering ordering my SBC-ID, but when I talked to my friend, he told me that getting a boost controller probably won't be worth it in an AT because it would probably shift up before I ever hit peak boost, let alone holding it. Is this true? I know there's a few people here on the board that have BCs in their automatics, so does his statement have any truth? I'd trust you guys more than him on this, since he says accidentally shifts from 2nd to 5th in his Si...heheh
 

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I really don't know what he is talking about. I have an HKS MBC and hit full boost very early with no tailoff in the higher gears. I don't know how much of an increase in power (say from bigger turbo, injectors etc.) that the AT can take but it seems to hold up well with the usual mods. Probably the biggest increase in performance can be had by upgrading the torque converter to a higher stall unit. Substantial improvements in ETs have been seen at the drag strip by those who have done this mod.

Dale
 

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Discussion Starter #3
Yeah I was thinking about torque converter but...not sure if I want to invest in that right now...

Does your MBC make your turbo spool up faster so that it can hit the peak boost then? No problems with it automatically shifting?
 

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Assuming that the automatic shifts at redline when the accelerator is floored, a boost controller is a worthwhile modification for the automatic WRX.

One only develops full boost when there is a demand for it (throttle position) and the engine rpms are high enough to spool the turbo.

A boost controller set at ~16psi would be a big help for the automatic. Since you have an automatic that you want to modify, you'll need a boost guage, so you can tell us what the peak boost in each gear is with the stock controller. I don't think we have that information yet!

-Jim
 

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Discussion Starter #5
Heh I can tell you that right now :)

With my Blitz Dual TT, I have a boost gauge. Whether or not it's accurate or not, I'm not sure...but I think it's safe to say it gives us a good ballpark, precise estimate of what I'm boosting. I was actually thinking about this on my way to work today, and glancing at my TT to check, so take these as unofficial results. Maybe this weekend I'll do some more accurate testing :) Anyway...

Weather: 40 degrees F, rainy and wet roads
Altitude: 50 ft. max above sea level

1st gear: ~0.76 bar = 11.02 psi
2nd gear: ~0.94 bar = 13.63 psi
3rd gear: ~1.02 bar = 15.08

I didn't get into 4th gear at all today, so I guess I'll leave that for the weekend. Again, I'll do more "official" tests this weekend :)
 

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I seem to remember reading in several of the reviews of the WRX that the AT has an automatic power mode (similar to the pwr/econ button that I have in my AT MR2) that engages automatically depending on how fast the trottle is depressed. I think that this changes the RPM points at which the trans shifts. I wonder if this would change your readings if this feature was or was not engaged.

Dale
 

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I use a Dawes Device MBC on my AT WRX. When I push the pedal to the floor it goes to redline before switching gears. Putting in a MBC made a big difference and I loose maybe .5 PSI by redline, but that is probably a charactoristic of the turbos Inefficiencies.
 
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