Collins

I am interested in getting a Sub-Zero ECU reflash thru Vishnu. I now have removed my after-market intake, since Shiv has explained that they are counter-productive if you want optimal reflash results. One remaining question: Can I leave silencer and scoop off, or should I put everything back on for successful reflash? Thru Shiv's explanation, I inferred that most, if not all problems arose from irregular MAF values, due to after-market diameter and flow characteristics. I'm not an engineer, so everything I infer could be wrong! My problem: I can't get an answer from Vishnu. I've called, left e-mail and PM messages. It's been over a week, so I'm searching for an i-club member with an answer. Trying to be a good sport, but really wish this vendor could meet me half way. Any and all feedback would be appreciated.
Thank You, Collins

Sonic1

You could put the scoop back onto the car, it helps get a little more cooler air into the wheeelwell now.

Collins

Thanks, that's a good idea. Heard back from Vishnu via e-mail, regarding my original question[Do I need the silencer for accurate reflash?]. Answer is "no", just stock airbox. I guess after-market MAF Housing diameters and irregular gas flow really was the problem, as I had hoped.[Really didn't want to re-open fender well if it wasn't necessary]. Thanks for response,
Collins

i-speed

The most important part is the air filter box and air filter size. once you start messing with the intake, and change it to a cone that air flow becomes much different. To explain it easily the ECU does not see this as a good thing unless you reprogram the ECU to understand the new air flow characteristics.

The one problem with this approach is that every cone filter is different by quite a bit. Therefore trying to even get remotely close to what Subaru has developed based on years of research is well pretty damn hard.

Collins

Thank You for your info! It certainly makes sense. I posted a thread approx. 1 month ago, and, after many replies, actually got one from the man himself. Shiv explained, much the same as You have, that aftermarket intakes often lead the ECU to incorrect, or varied gas flow/volume values. His reflash parameters for intakes must have a certain degree of uniformity in order for a"reflashed" ECU to respond optimally. Basically, just restating what You explained to me. My only question, on this thread, was whether I needed to install silencer for accurate reflash. Answer from Vishnu was "no"
My CAI is now removed, an OEM intake back in place. Just needed a cogent explanation as to why aftermarket intakes were "bad". Lot's of, THIS is "good", that's "bad" declarations in the forums, with no empirical explanation.
I'm not an engineer, but do have a workable understanding of Gas physics as they apply to human pathophysiology. The 'car' world is a completely new experience! Again, Thank You for the info.
Sincerely, Collins

wrxwagon2b

Im kinda new to the whole "Tune a Rex" thing. I have an understanding of what ur talking about with the CAI and the ECU not being able to get good performance due to more air flow but what is "reflash". I never heard that b4, plea elaborate...


thank you

i-speed

Reflash: The ECUTek software that certain comapny's have namely I-Speed USA and Vishnu can retune the stock ECU for more power with No mods or with minor or major mods.

The ECUTek is really a great software product, that keeps the stock ECU intact, so no worries about smogging and warranty. The other good part is the ECU itself. The OEM ECU is far better then just about any aftermarket ECU on the market, so harnessing the power of it is great.

Literally anything can be tuned for the WRX with the ECUTek software, including the flow characteristics of Turbo's and Intercoolers, exhuast systems and even different types of intakes. The only problem in tuning the intake, everyone of them is so damn different from the next. It would literally take days to get optimal values for each intake, which in the end would gain you little horsepower. The time and money versus power output doesn't make sense, so it is not worth tuning.