Is a 3 inch bumper exit exhaust restrictive ? T4 S480
03-16-2018, 03:44 AM
#1
Is a 3 inch bumper exit exhaust restrictive ? T4 S480 I’m going to run a full exhaust with my bw s480 but I’d like to run a short 3 inch down pipe dumped up front at the bumper. I plan on using an electric cutout or loud valve. The dumped pipe wouldn’t be much longer then 2-2.5 feet
Am I leaving a bunch of Hp on the table by doing it this way ?
My other option is to run a 4inch dumped down pipe up front and run a 3 inch Y off it to my back bumper.
If possible I’d like to stick with my first plan with the 3 inch dump upfront.
How long can I expect the electric cutout to live that close to a turbo ?
Id like to hear what you guys have to say. I’m trying to get away from running a full 4 inch exhaust to keep my ground clearance decent. It’s a street car that might make it to the track
a couple times a year at most
Am I leaving a bunch of Hp on the table by doing it this way ?
My other option is to run a 4inch dumped down pipe up front and run a 3 inch Y off it to my back bumper.
If possible I’d like to stick with my first plan with the 3 inch dump upfront.
How long can I expect the electric cutout to live that close to a turbo ?
Id like to hear what you guys have to say. I’m trying to get away from running a full 4 inch exhaust to keep my ground clearance decent. It’s a street car that might make it to the track
a couple times a year at most
Last edited by fastcars95; 03-16-2018 at 08:51 AM.
03-16-2018, 06:56 AM
#2
Restricted User
3" dump will support ~900 HP. The good thing about a cutout is that the exhaust isn't redirected. You will have the 3" dump PLUS the rest of your exhaust.
I wouldn't worry too much about it.
I wouldn't worry too much about it.
03-16-2018, 08:48 AM
#3
Can that little section cause too much back pressure ? Maybe Ill come off the turbo with a 4 inch pipe and Y to the cat-back while its still 4 inch and neck it down to 3 and dump it.
03-16-2018, 10:37 AM
#6
Originally Posted by Forcefed86
If you have a 3-4" dump... What is the point of running 3" to the back? Run come crush bent crap 2.5" with a decent OEM style muffler so it's actually quiet (and cheap).
03-16-2018, 11:17 AM
#7
Ah, gotcha.
Sounds like a sellable item… not to mention extra weight! Have a cheap exhaust shop install a single 2.25” crush bent quickie to the back with a Cadalliac muffler and you get the best of both worlds with a cutout!
Sounds like a sellable item… not to mention extra weight! Have a cheap exhaust shop install a single 2.25” crush bent quickie to the back with a Cadalliac muffler and you get the best of both worlds with a cutout!
Last edited by Forcefed86; 03-16-2018 at 11:37 AM.
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03-16-2018, 12:59 PM
#9
Im in the same boat. Already have the 3 inch set up on the car. Why get rid of it. Mine sounds good and on low boost should be plenty then when i decide to go to kill open the cutouts and race exhaust.
03-16-2018, 02:03 PM
#12
It seems the closer to the turbo the cutout is the shorter its life span.
Mine is located under the driver floor board near my feet with a front mount setup and has been in operation for over two years.
It seems like guys only get six months or so out of them when they're mounted close to the turbo.
Mine is located under the driver floor board near my feet with a front mount setup and has been in operation for over two years.
It seems like guys only get six months or so out of them when they're mounted close to the turbo.
03-16-2018, 05:52 PM
#13
Originally Posted by ls3fox
i would come off the turbo with 4" then split it to 2 3" should be more then enough but i wouldnt do 3" right off the turbo
Thanks.
03-16-2018, 09:07 PM
#15
I am curious about how loud and how quiet some are. I have heard some that seem pretty quiet, but my buddy just got his 6.0/475 running with a 4" downpipe, and its just freakin' loud. He was hoping to run just a downpipe, but thats clearly not going to happen now. Its almost if not as loud as his small block was with 3" exhaust. Do the wheels/ a/r have anything to do with how much they cut sound down?
03-16-2018, 09:17 PM
#16
Originally Posted by rpturbo
I am curious about how loud and how quiet some are. I have heard some that seem pretty quiet, but my buddy just got his 6.0/475 running with a 4" downpipe, and its just freakin' loud. He was hoping to run just a downpipe, but thats clearly not going to happen now. Its almost if not as loud as his small block was with 3" exhaust. Do the wheels/ a/r have anything to do with how much they cut sound down?
I've got a big old dirty cam and I live in Canada. So I have to run a full exhaust We can't get away with the stuff u guys can. I've never seen are car in Canada driving around with a bumper or fender exhaust.
We wouldn't make it across town without getting yanked
03-17-2018, 08:42 AM
#17
Not the same setup but a 5.3, ported heads, 218/228 custom blower cam (Engine had a centri) and it had 1 7/8 into 3” LT headers into a 4” merge necked down into a 3” Summit catback with a dynomax ultraflow SS muffler. Car was decently loud on the street and prob alittle too much for me.
same everything but took the supercharger off and added a CX single turbo kit 76/65 turbo single dumping into the same 3” catback with a 3” resonator where the merge was. Car is stupid quiet and sound gets alittle louder on the throttle. My WG dumps to atmosphere but have only need up to 6psi so it hasn’t opened (12psi spring). I like it a lot more than the supercharger as just cruising around the car is more enjoyable. I can get on it alittle more and more often without bringing any attention to myself. I put a dump on it but removed it before starting it with the turbo as I was worried about noise/leaks and rattling. Mines a street car so I won’t be in boost enough to warrant it and I’m not looking for every available HP.
Ive heard dumps before and they are quite loud even when the turbo is a muffler. I’m thinking I might need to put a muffler on the WG dump when I eventually hear it so t doesn’t scare the **** out of me.
same everything but took the supercharger off and added a CX single turbo kit 76/65 turbo single dumping into the same 3” catback with a 3” resonator where the merge was. Car is stupid quiet and sound gets alittle louder on the throttle. My WG dumps to atmosphere but have only need up to 6psi so it hasn’t opened (12psi spring). I like it a lot more than the supercharger as just cruising around the car is more enjoyable. I can get on it alittle more and more often without bringing any attention to myself. I put a dump on it but removed it before starting it with the turbo as I was worried about noise/leaks and rattling. Mines a street car so I won’t be in boost enough to warrant it and I’m not looking for every available HP.
Ive heard dumps before and they are quite loud even when the turbo is a muffler. I’m thinking I might need to put a muffler on the WG dump when I eventually hear it so t doesn’t scare the **** out of me.
03-17-2018, 09:10 AM
#18
Not the same setup but a 5.3, ported heads, 218/228 custom blower cam (Engine had a centri) and it had 1 7/8 into 3” LT headers into a 4” merge necked down into a 3” Summit catback with a dynomax ultraflow SS muffler. Car was decently loud on the street and prob alittle too much for me.
same everything but took the supercharger off and added a CX single turbo kit 76/65 turbo single dumping into the same 3” catback with a 3” resonator where the merge was. Car is stupid quiet and sound gets alittle louder on the throttle. My WG dumps to atmosphere but have only need up to 6psi so it hasn’t opened (12psi spring). I like it a lot more than the supercharger as just cruising around the car is more enjoyable. I can get on it alittle more and more often without bringing any attention to myself. I put a dump on it but removed it before starting it with the turbo as I was worried about noise/leaks and rattling. Mines a street car so I won’t be in boost enough to warrant it and I’m not looking for every available HP.
Ive heard dumps before and they are quite loud even when the turbo is a muffler. I’m thinking I might need to put a muffler on the WG dump when I eventually hear it so t doesn’t scare the **** out of me.
same everything but took the supercharger off and added a CX single turbo kit 76/65 turbo single dumping into the same 3” catback with a 3” resonator where the merge was. Car is stupid quiet and sound gets alittle louder on the throttle. My WG dumps to atmosphere but have only need up to 6psi so it hasn’t opened (12psi spring). I like it a lot more than the supercharger as just cruising around the car is more enjoyable. I can get on it alittle more and more often without bringing any attention to myself. I put a dump on it but removed it before starting it with the turbo as I was worried about noise/leaks and rattling. Mines a street car so I won’t be in boost enough to warrant it and I’m not looking for every available HP.
Ive heard dumps before and they are quite loud even when the turbo is a muffler. I’m thinking I might need to put a muffler on the WG dump when I eventually hear it so t doesn’t scare the **** out of me.
03-17-2018, 07:07 PM
#19
On a 5.3 running 14 lbs, S369 turbo, 3.5 downpipe to muffler then 3" to the rear bumper, I opened a 3" cut out at the end of the downpipe and the truck made 5lbs more boost and 100 more hp on my dyno, (Dj).
Last edited by kbracing96; 03-18-2018 at 11:32 AM.