onesillyracer Posted May 25, 2009 Share Posted May 25, 2009 ive been pondering with the idea of getting rid of the true bottleneck in the exhaust, the midpipe/y pipe, but is it worth the cost of doing so? just trying to determine the hp gains of going with a bigger diameter y pipe Link to comment Share on other sites More sharing options...
mwiener2 Posted May 25, 2009 Share Posted May 25, 2009 no 5hp maybe..... 15hp max but those gains are pretty much only at redline My Mods List (Updated 8/22/17) 2005 Outback FMT Running on Electrons Link to comment Share on other sites More sharing options...
pierce88 Posted May 25, 2009 Share Posted May 25, 2009 picked up 2/10s in the quarter when i swapped my mid and y pipes.... Definately worth it for me... Link to comment Share on other sites More sharing options...
mwiener2 Posted May 25, 2009 Share Posted May 25, 2009 2/10s could be anything from atmospheric conditions to driver to having 5 extra gallons in the tank. Unless you are a PROFESSIONAL drag racer or have hundreds of time slips to use for data, you can't say a few hundredths of second was due to this or that. Trap speed is a much better measure of power, but still not very accurate. Trap time is 90% driver. My Mods List (Updated 8/22/17) 2005 Outback FMT Running on Electrons Link to comment Share on other sites More sharing options...
pierce88 Posted May 25, 2009 Share Posted May 25, 2009 Drive a 5eat. Outside temp and Humidity was identical Picked up 3mph of trap speed Had 15 slips with 13.5xx @ 99.xx-100.xx Put mid and y pipes on and went back to back 13.331 and 13.393 @ 102.41 and 103.01 Definately think they helped. -Pierce Link to comment Share on other sites More sharing options...
rao Posted May 25, 2009 Share Posted May 25, 2009 I think I read where people picked up like 3/4 of a second.... Rob IF YOU CARE ABOUT YOUR CAR YOU SHOULD NEVER DRIVE IT Link to comment Share on other sites More sharing options...
mwiener2 Posted May 25, 2009 Share Posted May 25, 2009 Yeah, temp and humidity may have been CLOSE.... but what about atmospheric pressure? What about amount of gas in tank? Did you weigh yourself? Tire pressure? I'm sure it helped, but not to the extent that you think it did. My Mods List (Updated 8/22/17) 2005 Outback FMT Running on Electrons Link to comment Share on other sites More sharing options...
rao Posted May 25, 2009 Share Posted May 25, 2009 I didn't weigh myself but I weighed my tires. Rob IF YOU CARE ABOUT YOUR CAR YOU SHOULD NEVER DRIVE IT Link to comment Share on other sites More sharing options...
mwiener2 Posted May 25, 2009 Share Posted May 25, 2009 did you take into account treadwear from run to run? My Mods List (Updated 8/22/17) 2005 Outback FMT Running on Electrons Link to comment Share on other sites More sharing options...
rao Posted May 25, 2009 Share Posted May 25, 2009 Of course, when I rebuild my motor every day before I drive the car (and I now also rebuild the transmission as well) I measure the tread depth - I thought that was normal. Rob IF YOU CARE ABOUT YOUR CAR YOU SHOULD NEVER DRIVE IT Link to comment Share on other sites More sharing options...
mwiener2 Posted May 26, 2009 Share Posted May 26, 2009 I have 8 tires so that I can always match the 4 to within 0.02% tolerance so I don't fry differentials. My Mods List (Updated 8/22/17) 2005 Outback FMT Running on Electrons Link to comment Share on other sites More sharing options...
Guest Posted May 26, 2009 Share Posted May 26, 2009 I have 8 tires so that I can always match the 4 to within 0.02% tolerance so I don't fry differentials. I have 18 wheels. That allows me to keep the tolerance within 0.002%. Link to comment Share on other sites More sharing options...
atc5 Posted May 26, 2009 Share Posted May 26, 2009 I have 18 wheels. I demand a recount. I swear I counted 20 in there one day. Link to comment Share on other sites More sharing options...
Bolksey85 Posted May 26, 2009 Share Posted May 26, 2009 I demand a recount. I swear I counted 20 in there one day. The extra 2 are for when you have to haul a big load. Link to comment Share on other sites More sharing options...
Mr. Sinister Posted May 26, 2009 Share Posted May 26, 2009 Of course, when I rebuild my motor every day before I drive the car (and I now also rebuild the transmission as well) I measure the tread depth - I thought that was normal. Yeah, but what oil do you use? Link to comment Share on other sites More sharing options...
mwiener2 Posted May 26, 2009 Share Posted May 26, 2009 Mobil 1 My Mods List (Updated 8/22/17) 2005 Outback FMT Running on Electrons Link to comment Share on other sites More sharing options...
kevkel33leg05 Posted May 26, 2009 Share Posted May 26, 2009 allright back to the op question Here is a chart of my setup. Mods for the 266WHP and 311WTQ Hks catless up Xo2 catless dp xo2 FMIC Spec stage 2+ clutch Spec LWF Stock airbox Stock cbe TA Etune From adding just x02 mid and y pipe still (stock mufflers) and updated map gained 12WHP and 10WTQ noticeable in the mid range the most. http://i397.photobucket.com/albums/pp60/kevkel50/dynosheetsuny.jpg Link to comment Share on other sites More sharing options...
Legacy_GT_Pilot Posted May 27, 2009 Share Posted May 27, 2009 I just removed my XO2 intermeidate and Y-pipe as things were too loud. I haven't done a log since the change, but I'm still hitting target boost and holding it till redline. I wouldn't bother from a performance perspective. I'd personally be shocked if it gave you an extra 10whp as already stated. I will do a log when I get a few minutes for comparison to my prior tune and see what the difference is. FWIW I'm currently running a 20G on headers, an UP and DP. The rest of the exhaust is stock. Link to comment Share on other sites More sharing options...
Legacy_GT_Pilot Posted May 27, 2009 Share Posted May 27, 2009 What changed in your map? allright back to the op question Here is a chart of my setup. Mods for the 266WHP and 311WTQ Hks catless up Xo2 catless dp xo2 FMIC Spec stage 2+ clutch Spec LWF Stock airbox Stock cbe TA Etune From adding just x02 mid and y pipe still (stock mufflers) and updated map gained 12WHP and 10WTQ noticeable in the mid range the most. Link to comment Share on other sites More sharing options...
kevkel33leg05 Posted May 27, 2009 Share Posted May 27, 2009 Definitely should do it, it would be intresting to see the difference. I wish i could tell you what was changed in my map but i just got an updated Etune from mike at TA. Link to comment Share on other sites More sharing options...
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