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Old 10-07-2006, 04:44 PM   #193
Patrick Olsen
Scooby Guru
 
Member#: 120
Join Date: Jul 1999
Chapter/Region: AKIC
Location: Where the Navy sends me...
Vehicle:
1997 Legacy 2.5GT
1996 Impreza coupe

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Quote:
Originally Posted by FalconRS View Post
2. Not adding all the numbers together being obvious? Guess again. Most of the people asking the questions (newbies) that really need this sort of write up DON'T actually know that. Magazines aren't really any help, as most of the time magazines feature cars with 2-3 times the stock horsepower, and as Matt Monson pointed out, you don't believe a magazine. And as I point out everyday, you don't believe the claims of anyone who has something to gain by them, Vendor and Magazine alike. And all to often I run into a kid with a Civic or a Celica or whatever talking about his car, and his listing off the mods and how much power each one makes on his fingers, then claiming that's what he's now making.
I guess I'm confused as to which side you're on. You made that big long post, citing the ScoobySport car as an example of how the numbers were wrong, yet you based that claim on the number you generated by adding up all the numbers from this article. So are you a newbie that didn't realize you can't add all those numbers up and expect to actually get that out of the engine? Or were you already aware that that math never works that way in the real world? If it's the latter, then you could have taken the opportunity to say, "Hey, we should put a statement in this white paper explaining how different components work together on the engine, and that the power gains aren't all going to stack on top of one another." Instead, you jumped to the conclusion that all the numbers in this thread are wrong, which I think is the wrong conclusion to make.

Quote:
Originally Posted by FalconRS
3. The gains vary from model year. You yourself did a lot of great testing on the dyno, specifically your intake test. Unfortunately it's on a 97 with a much more simplistic ECU. The heavily-adaptive ECU's in the post-2000MY cars simply don't react to mods as well. And when you do gain something, generally a little driving adapts out most of the gains you made. Being that most of the newbies coming around these days are sporting 05-06 cars now, this is a significant point that needs mentioning.
I agree that the gains will vary from year-to-year. I'd love to see some exhaust comparisons using the new OEM equal length header, for instance (although we probably never will, since I think it requires a different oil pan.)

As for the ECUs, this is something that people claim over and over again, but I've never seen anyone actually prove that the ECU "learns around" modifications. I've read a number of threads in which guys say the car "felt slower" after they reset the ECU (or "felt faster" after they reset the ECU), but I haven't seen proof of that - 1/4mi times, dyno results, wideband O2 datalogs, whatever. It may very well be true, I honestly don't know, but I don't see any technical rigor to back up the claims.

Quote:
Originally Posted by FalconRS
4. Another issue I take with your test, that and you did the test with a header on the car, so airflow characteristic of the car was already improved to begin with, opening the door a little wider for the intake itself. This absolutely does affect the results, and was information completely left out of the original post.
Sport Compact Car's testing showed even bigger gains on a stock (or very nearly stock) '98 2.5RS. Maybe I'm just too trusting, but I have no reason to doubt their numbers. It's one thing to think there may be more at play when a magazine writes an article saying the new DCSports header for the Civic is awesome - there are thousands upon thousands of Civics out there to market to. I find it hard to believe, though, that SCC was skewing their reporting to generate increased sales of performance parts for the, what, 2000 2.5RSs there were in '98? Was Cobb Tuning lining SCC's pockets with the billions of dollars they're making off Subaru parts? (Hell, Cobb hardly even existed at that point, so maybe it was JC, the company that disappeared?)

I certainly don't think that this "white paper" is the be all, end all of Subaru N/A tuning. By the same token, as I've already said, I don't think any of the numbers claimed in this thread (other than 10hp for a muffler) are wrong - I think they're all +/- 1 or 2hp, which is as close as you can expect to get on this kind of thing. There is definitely more out there to be learned - I dropped a couple intake manifolds off at a machine shop yesterday for flow bench testing just because I want to know if there's any benefit to either of them. I've been hoping to do a dyno comparison of my Injen intake vs. an intake that retains the so-called "torque box" - I have the parts in my garage and just haven't gotten around to fabbing the torque box + Ebay tube intake. If I could I'd combine that testing with throttle body spacer testing, as I'm curious to see if those things really do anything or if the power and mileage claims are BS. Oh, and I have a bored out throttle body to test and those two intake manifolds, too. I don't imagine the bored out TB will do much, but I'd be really interested to see how (if?) the powerband shifts if I put an EJ20G intake (with its longer runners) on the engine. Maybe I'll get to some of this stuff, or maybe the EZ30-R that's sitting in my garage will make all of this moot.

Pat
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