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Old 02-01-2000, 02:53 AM   #1
Scooby Specialist
Member#: 292
Join Date: Sep 1999
Location: Elmer, NJ USA
2011 BMW 535i
Havana Metallic

Question Running lean on top end ('98 vs. '99)?

I ordered the Weapon-R intake after reading in SCC that a decent amount of power (15hp+) can be gained from intakes. I also read that the '99 that they tested on got very lean on the top end, and they needed to add an Apexi S-AFC to fatten up the fuel curve at high RPM's.

Now we all know that the 1999 Legacy 2.5GT uses the same DOHC engine setup as the 1998 2.5RS. My brother has a 98 RS, and the motor setup looks identical. All the failures with MAFs were 99 2.5RS's, so I am not worried about that (my brothers 98 with the Stage 2 minnam has never had MAF issues...I think they are more robust). We also heard that the 98 2.5RS's still run rich at high RPM with aftermarket intakes.

So, does this mean I can expect my 99 2.5GT to act like the 98 RS's when it comes to the intake? Is any of this making sense? Basically, my 99 uses the same setup as the 98 2.5RS, and it seems like the 98's were less picky towards intakes. If I don't need an S-AFC for my Legacy, I won't get it. I would rather concentrate serious mods on my DSM.


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Old 02-01-2000, 06:44 AM   #2
Subie Gal
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Member#: 301
Join Date: Sep 1999
Chapter/Region: NWIC
Location: WA
1970 FF-1 & '70 Van
02 WRX/01 RS


Kevin -
don't sweat it.... all of the MAF problems were (we've concluded) caused by the motion of the intake - too much of it. As long as you secure the intake correctly, your sensor should function as intended. I've had my intake for 7 months with absolutely no problems.

The car does tend to run a "bit" lean, but I don't forsee any problems with that at this point.

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Old 02-01-2000, 11:13 PM   #3
Scooby Specialist
Member#: 292
Join Date: Sep 1999
Location: Elmer, NJ USA
2011 BMW 535i
Havana Metallic


I am more concerned with running lean at top end causing the loss of horsepower. The SCC articale showed that the HP dropoff before adding fuel with the AFC at high RPM's was quite tremendous. That's why people with intakes keep saying the car seems to run out of breath at ~6K rpms.

Just wondering if it will be an issue with my 99, and should I start saving for an AFC.

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Old 01-29-2001, 01:00 PM   #4
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Member#: 2491
Join Date: Sep 2000
Chapter/Region: South East
Location: Charlotte, NC
06 Miata
81 Fiat Spider


Bringing this back up. I'm going to be getting a S-AFC from Dale Teague, and will keep you informed about the results. If I can fiqure out how to wire the damn thing!
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