Side bypass & down shifts
01-18-2019, 03:01 AM
#1
Side bypass & down shifts
Hey guys,
For those with side muffler delete/bypass, does your exhaust make a weird back-fire noise (as if the exhaust is being choked) when you rev match to downshift?
I've had a bit more seat time in my Touring today with 200 cell cats and non-valved side muffler deletes with the stock muffler. The soundtrack is great, it's just whenever I rev match to go to a lower gear, it seems like I'm choking the exhaust for that half a second of throttle blip. Curious if this is normal. This may also be applicable if you're running race headers with side muffler deletes as well (valved and non-valved)
Thank in advance
For those with side muffler delete/bypass, does your exhaust make a weird back-fire noise (as if the exhaust is being choked) when you rev match to downshift?
I've had a bit more seat time in my Touring today with 200 cell cats and non-valved side muffler deletes with the stock muffler. The soundtrack is great, it's just whenever I rev match to go to a lower gear, it seems like I'm choking the exhaust for that half a second of throttle blip. Curious if this is normal. This may also be applicable if you're running race headers with side muffler deletes as well (valved and non-valved)
Thank in advance
Last edited by SocalTouring; 01-18-2019 at 06:27 AM.
01-18-2019, 03:28 AM
#2
Race Car
Join Date: Jan 2013
Location: The way to hell is paved by good intentions “Wenn ich Purist höre...entsichere ich meinen Browning” "Myths are fuel for marketing (and nowadays for flippers too,,,)" time to time is not sufficient to be a saint, you must be also an Hero
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Which side bypass ? Dual or single pipe? Brand? 200cell from?
01-18-2019, 09:20 AM
#4
Burning Brakes
Is the HW newly installed? It might take some running time for the ECU to adapt to the new conditions i.e. lower back pressure.
01-18-2019, 12:40 PM
#5
01-18-2019, 12:52 PM
#6
Burning Brakes
It's a dirty job but someone's gotta do it...
(I envy you - here we have freezing temps for like two more months...)
(I envy you - here we have freezing temps for like two more months...)
01-18-2019, 01:45 PM
#7
Race Director
My GT3 is PDK, stock headers cats but with Soul dual outlet valved side by pass. I have the valved unplugged right now so they are always open....zero issues with sound or down shifts. No hoping noise at all.
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01-18-2019, 02:40 PM
#8
The FVD is a single pipe by pass....plus your 200 cell cats...did you get a tune also?
My GT3 is PDK, stock headers cats but with Soul dual outlet valved side by pass. I have the valved unplugged right now so they are always open....zero issues with sound or down shifts. No hoping noise at all.
My GT3 is PDK, stock headers cats but with Soul dual outlet valved side by pass. I have the valved unplugged right now so they are always open....zero issues with sound or down shifts. No hoping noise at all.
Yeah CA is great. I think we just got our annual allotment of rain this week and now it's sunny again =D
01-18-2019, 05:11 PM
#9
Race Car
Join Date: Jan 2013
Location: The way to hell is paved by good intentions “Wenn ich Purist höre...entsichere ich meinen Browning” "Myths are fuel for marketing (and nowadays for flippers too,,,)" time to time is not sufficient to be a saint, you must be also an Hero
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01-18-2019, 06:10 PM
#10
That will be similar to my setup - Cargraphics headers with 200 cell cats, single bypass, oe center. It sounds amazing, not as loud as I thought. Just the right amount of volume. Only thing is it drones like hell from 2-3K. I shift at 4K+ anyway so it doesn't bother me much.
01-18-2019, 09:26 PM
#11
Race Director
Hope you got all the rain gone...I’ll be in Anaheim on Tuesday till Saturday for my industries convention.
01-18-2019, 11:01 PM
#12
I have a pair of Fabspeed sidebypass pipes for sale on eBay. They are valved.
01-22-2019, 03:34 AM
#13
No drone in mine. Most all side delete pipes...valved and none valved use both rear muffler entries. Soul performance soulpp.com has a great cutaway photo on there website. So even with valves open or using there non valved version you get a small amount of bleed off into the top portion of the muffler.
Hope you got all the rain gone...I’ll be in Anaheim on Tuesday till Saturday for my industries convention.
yeah I was considering the non-valved dual like SoulPP’s piece but I’m thinking I need 100% to go through the top channel to eliminate the drone so valved seem to be the only way
Im curious if I’m the only one who’s having this issue. There’s definite a fluttering sound when I rev match for downshifts with these 200 cell headers and the side bypass... I’m sure there are others with 200 cell cats...
Last edited by SocalTouring; 01-22-2019 at 04:38 AM.
01-22-2019, 09:16 AM
#14
Race Car
Join Date: Jan 2013
Location: The way to hell is paved by good intentions “Wenn ich Purist höre...entsichere ich meinen Browning” "Myths are fuel for marketing (and nowadays for flippers too,,,)" time to time is not sufficient to be a saint, you must be also an Hero
Posts: 4,446
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yeah I was considering the non-valved dual like SoulPP’s piece but I’m thinking I need 100% to go through the top channel to eliminate the drone so valved seem to be the only way
Im curious if I’m the only one who’s having this issue. There’s definite a fluttering sound when I rev match for downshifts with these 200 cell headers and the side bypass... I’m sure there are others with 200 cell cats...
not tested wot but no issues and surprisingly no drones
https://rennlist.com/forums/991-gt3-gt3rs-and-911r/1035370-best-exhaust-for-a-991-2-gt3-60.html#post15580309
01-22-2019, 06:45 PM
#15
Thank you so much for that. Yours sound very similar to mine. There is a tiny bit of drone around 2-3K but I'm sure you're not noticing it. The only difference between yours and mine is the fluttering on downshifts. I will try to get an audio clip uploaded.
Which header do you have?
Which header do you have?