You're fine, stop listening to dumbasses. 
4" single vs 3" duals
Thread Starter
10 Second Club
Joined: Jan 2010
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From: Hurley, VA
4" single vs 3" duals I just made the change from 3" true duals ( a hack job) to a 4" single so I could pick up some ground clearance. Well after doing it everyone around here is saying I'm stupid for going to 4" single that I've lost power. I'm curious now as to whether this is true. Honestly looking at how my systems were curved the 4" looks to be a better flowing setup but I can't help but look at 2 3's equal 6 and a 4 is a 4. Have I given anything up going from the duals to the 4" at my power level. Its the H/C car in my sig. The car doesn't feel any different. And at what point will I out grow the 4" single.
I had a pretty nice set of 3" duals. I swapped them out for a mufflex 4" with magnaflow race muffler. I also switched from a ls6 intake, ported stock tb and lid to a ported 90mm fast, 90 tb and fast toys lid. I also upgraded to a ls6 maf while I was at it. The car felt alot stronger down low and seemed as strong if not stronger up top. My 3" duals tucked pretty good so ground clearance wasn't a primary concern. The duals were tearing the floor out of my car due to the way they were hung. I am glad I went to the single 4" and am keeping it with the 383 F1 combo. Did you use a cross flow muffler? Mine is a single in, single out.
Thread Starter
10 Second Club
Joined: Jan 2010
Posts: 2,317
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From: Hurley, VA
I'm running a single dynomax bullet lol. Its screams and my car feels alot smoother to me. Like the power band comes on alot smoother than before. I've only got maybe 2 feet of actual 4" pipe. Its dual 3" to the tailshaft of the transmission and then a 3 to 4 flowmaster merge and then the bullet with 4 inches of piping after it with a slashed end.
Thread Starter
10 Second Club
Joined: Jan 2010
Posts: 2,317
Likes: 20
From: Hurley, VA
My car seems to be just slightly quieter at idle but its still loud. How do you feel going by cops with your magnaflow? I've only had the set up a week or so and I was all ready considering going to a magnaflow muffler to quieten it down some.
On The Tree
Joined: Oct 2011
Posts: 102
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From: Dirty South
I just made the change from 3" true duals ( a hack job) to a 4" single so I could pick up some ground clearance. Well after doing it everyone around here is saying I'm stupid for going to 4" single that I've lost power. I'm curious now as to whether this is true. Honestly looking at how my systems were curved the 4" looks to be a better flowing setup but I can't help but look at 2 3's equal 6 and a 4 is a 4. Have I given anything up going from the duals to the 4" at my power level. Its the H/C car in my sig. The car doesn't feel any different. And at what point will I out grow the 4" single.
Dual 3" certainly provides more flow however, if the motor isn't flowing enough going too big causes you to lose power in some areas. I remember reading an article about a BMW race car team that actually went to a smaller exhaust and got a more broad power band that they wanted. It scavenged better.
In a H/C car I'd say the 4" would be better(maybe even too big). I'll be "upgrading" to a 3.5" which I think will be enough. It will still be better than the 3" single I have now.
In a H/C car I'd say the 4" would be better(maybe even too big). I'll be "upgrading" to a 3.5" which I think will be enough. It will still be better than the 3" single I have now.
Last edited by Exidous; Dec 28, 2012 at 01:41 AM.
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Lol,im sure its fine lol,im a fan of magnaflow outside of the catback system for our cars,bu,t there mufflers/race mufflers sound great,still the best setup for a street car imo is a magnaflow catback n cutout,best of both worlds,post a vid if ya can
I had a pretty nice set of 3" duals. I swapped them out for a mufflex 4" with magnaflow race muffler. I also switched from a ls6 intake, ported stock tb and lid to a ported 90mm fast, 90 tb and fast toys lid. I also upgraded to a ls6 maf while I was at it. The car felt alot stronger down low and seemed as strong if not stronger up top. My 3" duals tucked pretty good so ground clearance wasn't a primary concern. The duals were tearing the floor out of my car due to the way they were hung. I am glad I went to the single 4" and am keeping it with the 383 F1 combo. Did you use a cross flow muffler? Mine is a single in, single out.
Is the car raspy? Hows it sound? Im literally in the process of doing the EXACT same thing going from 3" TSP ORY with magnaflow 3" bullet to flowmaster 4" ORY and dynomax 4" bullet.
Dual 3" certainly provides more flow however, if the motor isn't flowing enough going too big causes you to lose power in some areas. I remember reading an article about a BMW race car team that actually went to a smaller exhaust and got a more broad power band that they wanted. It scavenged better.
In a H/C car I'd say the 4" would be better(maybe even too big). I'll be "upgrading" to a 3.5" which I think will be enough. It will still be better than the 3" single I have now.
In a H/C car I'd say the 4" would be better(maybe even too big). I'll be "upgrading" to a 3.5" which I think will be enough. It will still be better than the 3" single I have now.
Just remember it's not only the cross sectional area of the pipe... There's a lot going on "behind the scenes" as far as scavenging goes as well. An X pipe is always going to prevail and give you better midrange and upper RPM power.
Post #19 in the Mod Guide Sticky:
A 2.75” (stock) single system is good for a 310hp engine with zero loss…
A 3” Single system is good for a 370hp engine with zero loss…
A 3.5” Single system is good for a 503hp engine with zero loss…
A 4” Single system is good for a 657hp engine with zero loss…
A 2.25” dual system is good for a 457hp engine with zero loss…
A 2.5” dual system is good for a 513hp engine with zero loss…
A 3” dual system is good for a 812hp engine with zero loss…
A 2.75” (stock) single system is good for a 310hp engine with zero loss…
A 3” Single system is good for a 370hp engine with zero loss…
A 3.5” Single system is good for a 503hp engine with zero loss…
A 4” Single system is good for a 657hp engine with zero loss…
A 2.25” dual system is good for a 457hp engine with zero loss…
A 2.5” dual system is good for a 513hp engine with zero loss…
A 3” dual system is good for a 812hp engine with zero loss…
Hey RTBenny, I got them from the sticky in this section - https://ls1tech.com/forums/generatio...e-posting.html
It is the 19th Post in the sticky.
It is the 19th Post in the sticky.
I don't put a lot of faith into those numbers, seems to be a little on the generous side based on my results switching from dual 2.25" to dual 3" at my cam only power level.
That is why I posted up the sticky and the post number so that every one could see what all was involved in it. What results did you have from changing on your setup thunderstruck? Just curious.
When I was cam/bolt ons (350-370rwhp depending on the dyno and day) with 2.25" duals the car would routinely pick up .15-.2 and 1-2mph with open cutouts. This makes me think saying they should be good to 470 fwhp with 0 loss is on the very optimistic side.
Even now with 3" duals, the car picks up a small amount if I uncap the cutouts. It's usually around .5 mph which isn't much but still kinda contradicts the zero loss statement.
Maybe I'm thinking about it the wrong way? If so I apologize.
Even now with 3" duals, the car picks up a small amount if I uncap the cutouts. It's usually around .5 mph which isn't much but still kinda contradicts the zero loss statement.
Maybe I'm thinking about it the wrong way? If so I apologize.