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Old 01-13-2001, 11:00 PM   #1
nils
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Question 98RS - When is an AFC req'd?

I've got a minnam intake, a 2.25" SPD midpipe, and stromung dual tip on my 98RS, but no EGT guage. I realize an S-AFC would help, but is it req'd?

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Old 02-07-2001, 05:02 AM   #2
hacman
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TTT

I'm curious too. I'm considering buying one right after I do the stromung.
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Old 02-07-2001, 05:47 AM   #3
bratmantlz
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Thumbs up

i am getting an exhust after a while and am hoping to get my s-afc installed with a air fuel meter on a pillar mount soon. uhh i dont know if it req'd but you could probably get more hp out of it. if i can i will get some pics up of it installed when the time comes. oops i have a 98 too

[This message has been edited by bratmantlz (edited February 07, 2001).]
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Old 02-07-2001, 09:29 AM   #4
BoomerRS
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98RS
jc sports intake
autometer air/fuel gauge

i seem to be running fine with the intake. granted with an AFC i could prob get some more power out of it. i run slightly rich at WOT which is what i would want. the intake came before the a/f gauge so i dont know the difference from stock.
not sure if this helped any
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Old 02-07-2001, 10:31 AM   #5
Tangmere
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I'm under the impression that we '98 owners don't need it. I asked RalliSpec about it, they said if I want pretty lights, sure get one. Our cars don't respond well enough to one to warrant the expense. I guess that's good(?).
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Old 02-07-2001, 10:40 AM   #6
bratmantlz
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hey tangmere what about if we run a intake and it runs lean or whatever, this should help tune out the engine make it run more efficiant to suit the conditions? possibly get a bit more hp out of the engine....
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Old 02-07-2001, 06:32 PM   #7
hacman
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The way I understood it (correct me if I'm wrong), getting the AFC would help after the intake/exhaust with the upper revs. At WOT, above 5500, we're running lean, right? That mod would help fix that?

After intake and exhaust, what would be the next logical step for bolt on NA performance?
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Old 02-07-2001, 06:42 PM   #8
bratmantlz
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thats what i thought as a matter of fact i have already got my exhaust picked out.
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Old 02-07-2001, 06:57 PM   #9
Tangmere
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Our cars will not run lean after an intake is added. The fellows at RalliSpec ran some kind of meter (I don't remember which)plugged into the ECU after the intake install for this very reason. The car ran perfectly throught the entire rpm range and the reading was right where it should've been, we did this more than once. I tell you the S-AFC is a waste of money on a '98 IMHO.
Believe me I wanted one! My friend back east Eric K is pulling 200 hp normally aspirated without cams! He can tune his with an S-AFC because of the type of MAS, or whatever he has in his '99. But I was told again and again '98s don't respond to the S-AFC. They are not needed.
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Old 02-07-2001, 07:11 PM   #10
bratmantlz
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well tangmere i was told by larry ganz that the s-afc didnt do much for his 2000 and that with the jcsports intake would help as it does run lean or whatever as mentioned above for higher rpms for my 98RS.
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Old 02-07-2001, 07:48 PM   #11
Quart2000
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The marc 2000 issue of Sport Compact Car did comparison tests with a few intakes and exhausts with dyno results. your intake and exhaust combo had the highest increase at 20 percent yes 20 percent in wheel horsepower and estimated at about 185-190 engine horsepower. Here is the bad part these increases were with a SAFC because without it there was a loss of power at 5500rpm and above because of, now read this part!! the engine was running "dangerously lean" as they said triggering the knock sensor retarding the timing.
So I would recommend an SAFC for those reasons.
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Old 02-07-2001, 08:21 PM   #12
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If you have an NA car that you don't plan on turboing, then the afc doesn't do too much besides trick the ecu into thinking that more air is being taken or put into the engine. If you have an a/f meter then you can tune your rpm curve so that you keep your mixture just right, you can relly only yield maybe a few horses, but it's more accurate to tune on a dyno.
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Old 02-07-2001, 08:55 PM   #13
Gambit
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Quart : the article was based on a 99 RS. It is different than the DOHC phase I 98RS engines. So you cannot base those results and adapt it to a 98RS.
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Old 02-07-2001, 09:04 PM   #14
bratmantlz
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okay i am thuroughly confused Larry were are ya i understood when you explained it and since my accident i must have forgot can you clarify? hehe or someone i.... oh boy in my RS i hit 90mph and the rpm's suddenly drop a 1000 or 1050 then even out from what i get the s-afc will assist me in tuning the engine to run better or more efficient or something....
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Old 02-07-2001, 09:07 PM   #15
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Ditto
The test was on a 99, not an 98. I think if you have a turbo, you might want to invest

[This message has been edited by Zeta (edited February 07, 2001).]
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Old 02-07-2001, 10:56 PM   #16
hacman
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okay.... so bottom line.... after intake/exhaust, there's no real reason to have any supplemental electronics without turbo? I've read about the differences with the 98 against the 99s, so I'm only referring to the 98s.

What are the other power adders we can do to our 98s, and keep it CARB legal? Cams would be the next step?
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Old 02-08-2001, 07:05 AM   #17
Gambit
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no cams yet for 98 RS. Unless u go custom make which will cost you a bundle. Not to mention it's a DOHC so you need twice as much more cam shafts than the SOHCs. hehehehe.... so turbo route is better IMHO.
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Old 02-08-2001, 10:31 AM   #18
smacksube
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you could just do what I'm planning on doing which is trying to transplant a wrx motor into my01 rs. I found a site that is selling the motor, mounts, tranny, ecu and wiring harness for 2700, which is what I would be spending on a turbo, piping, fuel system and a rebuild, but I still have some more research to do to see if the swap will fit. Anyone know if this is a possibility, because I'm not beyond just putting a poop load of money into the ej25, which is what I think will happen anyways
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Old 02-08-2001, 11:00 PM   #19
hacman
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smacksube - What is that URL? Also, do you know if we can do the transplant, and make it carb legal?
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Old 02-09-2001, 07:05 AM   #20
smacksube
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ahh, see I live in florida and in my county they took away emissions testing so I don't have to worry about keeping it emissions legal for the time being anyways. One of the sites I was looking at is http://www.adelaidejap.com.au/subaru.htm
and another good one is http://www.jaustech.com.au/
I'm assuming it can be carb legal or whatever because the new wrx's are based of off the ej20 engine, they're just debunked a bunch of Hp.
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Old 02-09-2001, 11:22 AM   #21
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Just a question about the AFC being able to adjust the leaning out of the motor, and making more HP? I could be totally wrong but hear me out. I race Gas RC cars. okay,okay, before I get my head bit off let me explain. When you lean out a motor on a nitro car, IT goes FASTER, runs hotter, and makes you get better mpg, because it uses less fuel. Now with that being said, I believe if you use the AFC to richen the mixture it will slow it down. Creating Less HP at WOT.

I too have a 98, and NO AFC. I don't believe it is running lean. Now what I think the AFC can do is adjust the A/F mixture throughout the powerband and compensate where it is rich and where it is lean, therefore making it more efficient. If it can do that, then I say get it, but it seems that people have already tested it and say it just looks cool for the N/A 98's. But if you use it to just richen the mixture, you will hurt performance by wasting fuel and slowing it down.

I truly don't think we need it unless we go the forced induction route, but I've been wrong many times and I'm sure I'm not done making mistakes.
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Old 02-10-2001, 04:40 PM   #22
hacman
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Pinoy - That's what I thought too.... but apparantly, the 98s don't get the run-lean condition in the upper RPMs like the 99+ do.

I'm so confused!!
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