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2000 2.5RS BRP
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Discussion Starter #43
Drive-through cashiers hate me. It's like trying to take an order from a hovering helicopter. THOP-THOP-Hi-THOP-THOP-like-THOP-THOP-shake-THOP-THOP-THOP-THOP-THOP-WAT???-THOP-THOP-THOP-THOP.
 

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The subaru of many acronyms
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Drive-through cashiers hate me. It's like trying to take an order from a hovering helicopter. THOP-THOP-Hi-THOP-THOP-like-THOP-THOP-shake-THOP-THOP-THOP-THOP-THOP-WAT???-THOP-THOP-THOP-THOP.
My 7.3 ferd is the bane of drivethrough existence, doesn't fit and shakes the whole building lol
 

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2000 2.5RS BRP
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1,181 Posts
Discussion Starter #46
I indexed the sparkplugs today. With no other tuning changes, it definitely picked up a little giddyup. Fuel trims are more stable. Tip-in and top end are noticeably quicker.
 

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Discussion Starter #47 (Edited)


There's that damn rev limiter killing all the fun again. This engine loves to spin and it needs another 1,000rpm to really be effective. I'd gain about 10mph in each gear with 1,000rpm more. 5500-7500 is where the fun is at.
 

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V4 Sti BRP, 98LGT SP, 94SVX PW
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Sup G,
I've been busy and completely forgot about checking this out.

In regards to "this bog at low-mid rpm and high load"
Is this the same bog all RS'es have? When still NA I sorted mine by correcting my car's grounding. Never had that dip again.

Stop by the shop (610 Pratt Ave. NW) sometime.
 

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2000 2.5RS BRP
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1,181 Posts
Discussion Starter #53
Bumpdate.

I'm making some interesting headway with further tuning.

The twin intake allows very high MAP readings at very part throttle. It can hit 96kpa at 20% throttle. This is a common theme among ITBs and is nothing new or shocking. I'm working on using this fact of life to my advantage with tuning. The advantage over ITBs with this setup is having longer runner length, a stable MAP signal for all cylinders, and relative mechanical simplicity. This makes tuning a little easier for me. However, the combination is so new, that there are no base maps for me with start with other than a stock map. The bugs are new, too.

I admit to fumbling through the dark just a little bit to find the right settings. I'm happy with the car, but perfection in the tune has been a little hard to come by. Compromise keeps rearing its ugly head. I have to drive the car like a complete wuss in traffic to avoid tickets. What works in lower gears doesn't work so well in higher gears. I have to work the throttle to get the most out of it. My friends and I agree it is like playing an acoustic Subaru instead of an electric Subaru.

N/A's are forgiving of mistakes but demanding of precision (until you run crazy compression, big cams, nitromethane, etc.) I've been hunting for that precision a little bit at a time, whittling away unnecessary bits. I've chased down a thermal bug that causes the idle to change with different weather. Mike has provided a few new tables for me to work with, like programming the IAC. I was working with the IAC tables before figuring out the thermal issue and addressing it physically.

So far so good. The noise gets to be a bit much at times, but I'm sleeping in the bed I made. It does make a quiet daily sound very, very nice. I would not have signed up for this if I thought it wouldn't work or wouldn't love it. I spend more time under the hood making improvements as opposed to mistakes or fixing problems. Less seasoned people would be bugging the hell out of a tuner over every little thing that I accept as simply part of life with this choice. The car would not even be running if I had not stayed on top of things and applied myself to finding the solutions needed.
 

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Discussion Starter #56
I think the biggest detriment to performance is the inactive AVCS. No real cam overlap kinda kills the fun. If I could raise the redline, then it would be a lot better, but I digress. The whole combination is an experiment and is as reliable as one could expect. My next motor will have static cam gears. AVCS when not hooked up will still move around a little with oil pressure, but not enough to really help or hurt. They really need to be degreed correctly.

I can switch up between 93 and E85 pretty easily. It takes a little driving to let the car relearn, but it adjusts fairly quickly on the change up. Mixing fuels doesn't hurt either way, so I can change up at 1/4 tank and it runs fine. I still have not tried 104 unleaded. That should be fun.

Sorting the mundane details have kept me busy. I am still stripping weight out here and there, whittling a piece at a time.
 
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