Mismatching inlet diameters

TPrelude-370z · 08-01-2023, 04:27 PM

Hello,

Quick question: I have a Beluga Racing Y-pipe, and Beluga axle back (both 2.5” inner diameter), attached to the stock midpipe (2.25”). It sounds great, but I’m curious if there’s a significant enough performance difference that warrants purchasing a matching midpipe, or completely new exhaust system.

I’m not proud, but I can’t be the only one who has frakensteined an exhaust together.

ZStalker505 · 08-03-2023, 11:54 AM

I wouldnt see any issues with the setup unless you dont like the catback sound. If you are going to try to push power you could get some 2.5 test pipes. I have the opposite problem I have 2.5 test pipes and the previous owner/shop put a 2.25 cat back on it for some strange reason. I want to change it out but I'd like to maybe set up a buyer for the current catback obviously for $ concerns before I take it off and it sits in the back yard.

SkysG37 · 08-04-2023, 01:31 AM

Definitely a bottle neck with the smaller in the middle.
No problem stepping up as you go back and might even help flow as the gasses expand.

I had a horrible drone with (anti reversion) test pipes, a megan Y, stock mid and medallion axle backs.
Was looking for a properly sized mid pipe when I decided **** it.
And went with long tubes plus a full cat back system.
So I can't tell you if the stock mid pipe was to blame or not.

08-01-2023, 04:27 PM	#1 (permalink)
TPrelude-370z Base Member Join Date: Jul 2011 Location: Chicago, Il Posts: 243 Drives: 09-Tour-Sport-MB-6MT Rep Power: 14	Mismatching inlet diameters Hello, Quick question: I have a Beluga Racing Y-pipe, and Beluga axle back (both 2.5” inner diameter), attached to the stock midpipe (2.25”). It sounds great, but I’m curious if there’s a significant enough performance difference that warrants purchasing a matching midpipe, or completely new exhaust system. I’m not proud, but I can’t be the only one who has frakensteined an exhaust together.

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08-03-2023, 11:54 AM	#2 (permalink)
ZStalker505 Base Member Join Date: Jan 2023 Location: NM Posts: 185 Drives: 14 SC Nismo Rep Power: 2	I wouldnt see any issues with the setup unless you dont like the catback sound. If you are going to try to push power you could get some 2.5 test pipes. I have the opposite problem I have 2.5 test pipes and the previous owner/shop put a 2.25 cat back on it for some strange reason. I want to change it out but I'd like to maybe set up a buyer for the current catback obviously for $ concerns before I take it off and it sits in the back yard.

08-04-2023, 01:31 AM	#3 (permalink)
SkysG37 Base Member Join Date: Jun 2019 Location: Fort Myers Florida Posts: 25 Drives: SC '08 G37 coupe Rep Power: 6	Definitely a bottle neck with the smaller in the middle. No problem stepping up as you go back and might even help flow as the gasses expand. I had a horrible drone with (anti reversion) test pipes, a megan Y, stock mid and medallion axle backs. Was looking for a properly sized mid pipe when I decided **** it. And went with long tubes plus a full cat back system. So I can't tell you if the stock mid pipe was to blame or not.