Are Cut-Outs worth it ?? / Where to install it ?
Really depends on your exhause set up. My boy has a camaro ss with,383ci kook 1 3/4 headers,off roads and his factory center mount catback. He gaines 5hp opening cutout. My 402ci with kook 1 7/8,offroads and the shitty b&b tryflo(worse cat for power) i gain 30hp opening the cutout. My ls1 gained 18hp same exhaust.
well my exhaust set-up is a set of SLP 1 3/4 LT's with SLP Y-Pipe w/ gutted catz and the factory SLP Dual-Dual that came with my SS. I can't complain cause it seems to be flowing pretty good as is. My exhaust is nice and quiet until I put my foot down 
.
I appreciate all the replies fellas. Different views are very important to me on trying to make a the right choice for my ride. ..LOL..I always use to say that I would never cut my stainless-steel 304 exhaust when I bought the car new back in 02'...Now I'm really thinking about doing it.
.I appreciate all the replies fellas. Different views are very important to me on trying to make a the right choice for my ride. ..LOL..I always use to say that I would never cut my stainless-steel 304 exhaust when I bought the car new back in 02'...Now I'm really thinking about doing it.
Fwiw, with my old 13.5 to 1 402 setup, I went 9.5 with a 3.5 inch dual exhuast with super 44 series mufflers, and I went 9.5 with the system off, running strait out the 3.5 inch collectors that were on the kooks headers....
What does that mean? It means, that the exhaust was big enough so that it wasn't a restricition and wasn't costing me any power. Car mph'd in the 142.x range both with it off and with it on. Granted it was different tracks/days, but you get the idea. It wasn't hurting the car at all.
If you run a big enough system, you won't see any gains by taking it off. h/c anything that's stock CI 3 inch dual/dual will probably support as much as the motor can make, under 427 a dual 3.5 inch system should be adequate, over 427 I'd be running dual oval pipe that's equivalant to 4 inch pipe. It's an easy thing to make and can tuck up pretty good, and it wasn't very loud either, fwiw. And once I painted it flat black, you couldn't even see it from the side of the car unless you stuck your head under it.
Cutouts, are to me a band aid for an inadequate sized exhaust system, or for the guy that has to keep it quiet to drive it around, and wants the car to run at the track like it should if he could run an adequate system on the street for max power.
Under the passenger's seat is the easiest spot to put one on a 4th gen car, closer to the merge collector the better it will work when open, and the more it will choke the car up when it's closed.
What does that mean? It means, that the exhaust was big enough so that it wasn't a restricition and wasn't costing me any power. Car mph'd in the 142.x range both with it off and with it on. Granted it was different tracks/days, but you get the idea. It wasn't hurting the car at all.
If you run a big enough system, you won't see any gains by taking it off. h/c anything that's stock CI 3 inch dual/dual will probably support as much as the motor can make, under 427 a dual 3.5 inch system should be adequate, over 427 I'd be running dual oval pipe that's equivalant to 4 inch pipe. It's an easy thing to make and can tuck up pretty good, and it wasn't very loud either, fwiw. And once I painted it flat black, you couldn't even see it from the side of the car unless you stuck your head under it.
Cutouts, are to me a band aid for an inadequate sized exhaust system, or for the guy that has to keep it quiet to drive it around, and wants the car to run at the track like it should if he could run an adequate system on the street for max power.
Under the passenger's seat is the easiest spot to put one on a 4th gen car, closer to the merge collector the better it will work when open, and the more it will choke the car up when it's closed.
Up until last weekend I had:
Longtubes with 3" to 2.25" reducers (junk...long story) into 3" dual pipes, to dual 3" cutouts 1 foot behind the collectors, to flowtech terminator mufflers to 2.25" tails over the axle. On this setup I always gained over .1 and 1mph at the track (usually .15 and 1.5mph) with both cutouts open.
I recently cut the tails off so now that the restriction is minimized I doubt the gains would be as substantial.
Car gets REALLY loud with them open and stinks like crazy. The exhaust note of open cutout is terrible...loud, but terrible...like a Harley from hell (personally I think 90% of harleys sound like **** anyway, all noise and no tone)
Longtubes with 3" to 2.25" reducers (junk...long story) into 3" dual pipes, to dual 3" cutouts 1 foot behind the collectors, to flowtech terminator mufflers to 2.25" tails over the axle. On this setup I always gained over .1 and 1mph at the track (usually .15 and 1.5mph) with both cutouts open.
I recently cut the tails off so now that the restriction is minimized I doubt the gains would be as substantial.
Car gets REALLY loud with them open and stinks like crazy. The exhaust note of open cutout is terrible...loud, but terrible...like a Harley from hell (personally I think 90% of harleys sound like **** anyway, all noise and no tone)
Thanks for all the input fellas. Man, I may have to re-think this cut-out thing again. I have all the time in the world.
"Granted it was different tracks/days, but you get the idea"
i would think you would know that with all of the different variables at the track that the times are irrelevant
and to the OP i think cutouts are a great idea. i have been through multiple exhaust systems and now i have them all. when the cutouts are closed you cant hear a thing due to the exhaust running through two large factory mufflers, and i have the choice to open those electric cutouts to ANY percentage, therefore having any sound i want from factory quiet to open headers
i would think you would know that with all of the different variables at the track that the times are irrelevant
and to the OP i think cutouts are a great idea. i have been through multiple exhaust systems and now i have them all. when the cutouts are closed you cant hear a thing due to the exhaust running through two large factory mufflers, and i have the choice to open those electric cutouts to ANY percentage, therefore having any sound i want from factory quiet to open headers
LS1 Tech Stories
The Best V8 Stories One Small Block at Time
6 Common C5 Corvette Failures and What's Involved In Repairing Them
Pouria Savadkouei
Retro Modern Bandit Pontiac Trans AM Comes With Burt Reynolds' Autograph
Verdad Gallardo
Top 10 Greatest Cadillac V Series Performance Models Ever, Ranked
Pouria Savadkouei
Top 10 Most Powerful Chevy Trucks Ever Made!
Hennessey's New Supercharged Silverado ZR2 Has 700 HP
Verdad Gallardo
Coachbuilt N2A Anteros Is an LS2-Powered C6 Corvette In Italian Clothes
Verdad Gallardo
Awesome K5 Blazer Restomod Comes With C7 Corvette Power
Verdad Gallardo
10 Camaros You Should Never Buy
10 LS Engine Myths That Refuse to Die
Verdad Gallardo
TECH Apprentice
Joined: Jan 2011
Posts: 309
Likes: 1
From: Australia
im running 2in headers 4into 1 with 3.5in collectors 3in cats then twin cutouts and they are way too loud this time round compared to when i had the 5.7L with 1 3/4in headers and 2.5in cats im taking them off also the electric motors are not strong enough to completely close even at idle oonly when the car is off too much exhaust pressure holding them slightly open so going back to stock.
also just found out xforce here in australia sell what they call a varex muffle its the same sort of thing but on the muffle it sends more gases through the baffles when closed or straight through muffle when open going to get this so i can make it quiter cause as is with a twin 3in system and straight through mufflers im way over the legal sound limit here in australia.
also just found out xforce here in australia sell what they call a varex muffle its the same sort of thing but on the muffle it sends more gases through the baffles when closed or straight through muffle when open going to get this so i can make it quiter cause as is with a twin 3in system and straight through mufflers im way over the legal sound limit here in australia.
Does a cutout help? YES
Is the help dyno proven? YES
Is a cutout loud? YES
Can you close a cutout either manually or electronically to reduce noise when not desired? YES
I got a 7 hp increase open cutout in back to back dyno runs contrast to it closed!
Is the help dyno proven? YES
Is a cutout loud? YES
Can you close a cutout either manually or electronically to reduce noise when not desired? YES
I got a 7 hp increase open cutout in back to back dyno runs contrast to it closed! 
Mac , you know my car and I have a cut out installed but have never really seen any gains at the track(never did any dyno runs ) ,cant remember the last time I opened it up.I think the dual/dual exhauast we both have is a very good system.But it did sound good when it was opened.
I gained 18 rwhp with my 3.5" cutout over my factory dual dual muffler. Everytime I open it at the track I gained 1.5-2 mph. Now I recently installed a 4" dmh electric cutout, no more ******* with wing nuts under my car. One of my favorite mods so far.
Went back to the track and did a back to back run. Now that I don't have restrictive tails, the cutouts gain nothing.
108.38 mph to 108.4 on 2 back to back passes with cool down time between
this is with a 3" dual setup with no crossover pipe through Flowtech Terminator mufflers
108.38 mph to 108.4 on 2 back to back passes with cool down time between
this is with a 3" dual setup with no crossover pipe through Flowtech Terminator mufflers
