Exhaust diameter 2.5" vs 3"... Noticeable difference?
04-17-2018, 12:09 PM
#1
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Exhaust diameter 2.5" vs 3"... Noticeable difference?
Finally going to order my turbo kit. I currently have a 2.5" cat back exhaust going into an ANSA silverline dual outlet exhaust. This exhaust came on the car when I purchased it a few years ago, but I really enjoy the sound. I'd like to keep it and save some cost on the turbo kit, however I realize that a 3" exhaust would be better. My question though, is how much better? Does anyone have any concrete stats comparing the 2 sizes?
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04-17-2018, 02:08 PM
#5
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You can keep the small exhaust for now if youre trying to save money. If its just a street car it will still be a load of fun even if it isnt optimized to the max.
Maybe in a couple years youll throw a full 3" at it with the MTnet approved muffler and see what you were missing.
Maybe in a couple years youll throw a full 3" at it with the MTnet approved muffler and see what you were missing.
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04-17-2018, 03:20 PM
#7
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If Flyin' Miatas numbers are to be trusted, on a 266rwhp 1.8 they got 16hp and boost 200rpm earlier with a 3" exhaust vs a 2.5".
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04-17-2018, 03:54 PM
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If Flyin' Miatas numbers are to be trusted, on a 266rwhp 1.8 they got 16hp and boost 200rpm earlier with a 3" exhaust vs a 2.5".
It's definitely louder than stock by a few decibels, but has a really nice deep tone at a low pitch. I would like to say it's not obnoxiously loud, but I've had some neighbors complain about the rumble from my morning warm-up enrichment cycles lol.
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04-17-2018, 09:18 PM
#12
Lots of good info proves 3”>2.5”. Where things got fuzzy for me was length and muffler volume. With the smaller 2.5” size I was able to get 2 smallish mufflers in-line and terminate just before the diff. With the 3”size I would not have enough muffler volume in the same location. I would have to use a large oval in the back and terminate near the bumper.
With my 300 WHP 9 psi Rotrex It was hard to imagine the larger size helping out. If anything it may have hurt midrange torque where I needed it the most. Someday I’ll pull the system and dyno it wide open just to see how much it’s holding back HP.
Just another perspective to consider for SC cars.
With my 300 WHP 9 psi Rotrex It was hard to imagine the larger size helping out. If anything it may have hurt midrange torque where I needed it the most. Someday I’ll pull the system and dyno it wide open just to see how much it’s holding back HP.
Just another perspective to consider for SC cars.
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04-17-2018, 10:24 PM
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Lots of good info proves 3”>2.5”. Where things got fuzzy for me was length and muffler volume. With the smaller 2.5” size I was able to get 2 smallish mufflers in-line and terminate just before the diff. With the 3”size I would not have enough muffler volume in the same location. I would have to use a large oval in the back and terminate near the bumper.
With my 300 WHP 9 psi Rotrex It was hard to imagine the larger size helping out. If anything it may have hurt midrange torque where I needed it the most. Someday I’ll pull the system and dyno it wide open just to see how much it’s holding back HP.
Just another perspective to consider for SC cars.
With my 300 WHP 9 psi Rotrex It was hard to imagine the larger size helping out. If anything it may have hurt midrange torque where I needed it the most. Someday I’ll pull the system and dyno it wide open just to see how much it’s holding back HP.
Just another perspective to consider for SC cars.
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