400 RWHP Should I go with a 3.5 or 4 inch catback.
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400 RWHP Should I go with a 3.5 or 4 inch catback.
LS1 Speed makes a catback in 3.5 and 4 inch. You can choose a Flowmaster or Spintech race muffler. Has anyone seen gains from increasing the exhaust size?
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Re: Anyone make a 4inch catback or a bolt on Dual setup?
I think flowmaster does but I don't like them and I heard they suck. I might go with duals and use those Spintech Mufflers. I hear they kick but and I heard a clip with them. By the way, where can I buy Spintech Mufflers?
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Re: Anyone make a 4inch catback or a bolt on Dual setup?
Perfect! WHere can I buy it. What kind of gains can I expect running a 4 inch catback. I am thinking of running a 3 inch into 4 inch collector.
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Re: Anyone make a 4inch catback or a bolt on Dual setup?
My car makes 400 RWHP and 380 RWTQ. I've read that anything over 350 hp requires a 3 1/2 or 4 inch. I just want to know if anyone got decent gains from this mod.
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Re: Anyone make a 4inch catback or a bolt on Dual setup?
4" is probably too big. The LS1 likes a little backpressure. I would say anything over 3.5" is not going to help you much if at all.
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Re: Anyone make a 4inch catback or a bolt on Dual setup?
People are going nuts with the big pipe craze.. The rule of thumb has always been when to go from 2.5" to 3" based on HP. The consensus is, 500 engine HP makes an argument for 3" pipe. As far as 4", 5", 17" or whatever the exhaust company of the day thinks up, it sounds like a lot of over-kill that is going to have really bad sound characteristics.
By my rough math, 400 RWHP will be right around 500 FWHP, give or take.. I'd say you're only gambling with 5 hp between 2.5" and 3" catbacks.. I seriously doubt there is anything beyond that to be gained at that power level with 3.5" or above. IMO
By my rough math, 400 RWHP will be right around 500 FWHP, give or take.. I'd say you're only gambling with 5 hp between 2.5" and 3" catbacks.. I seriously doubt there is anything beyond that to be gained at that power level with 3.5" or above. IMO
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Re: Anyone make a 4inch catback or a bolt on Dual setup?
1999, ur right on ur numbers, but they r basing that on going from a 2.5" to a 3" running DUALS, not a single 3" like the F-bodies do... dual 2.5" is equal to a single 3.5" in actual area...
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Re: Anyone make a 4inch catback or a bolt on Dual setup?
You dont want to go to big then you could possibly loose horsepower Dont want that.I have 410 rwhp and am running 3.5" makes great power let us know what you choose-also have you thought about a bullet muffler or borla xr1-those are good too.
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Re: Anyone make a 4inch catback or a bolt on Dual setup?
Something to be aware of regarding the performance through a Spintech: https://ls1tech.com/threads/showflat...31&fpart=1
I'm not saying that it won't work for you, I'm just sharing my experience.
I'm not saying that it won't work for you, I'm just sharing my experience.
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Re: Anyone make a 4inch catback or a bolt on Dual setup?
stick with the 3", the only time i have seen alot of 4" is on turbo lt1's, where they want the higher exhaust velocity. If you are going to change out exhaust i would go true duals, a 4" is mainly when you have a power adder.
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Re: Anyone make a 4inch catback or a bolt on Dual setup?
We have a lot of opinions here and zero facts and data. The reality is that when you have ~500 FWHP you need the equivalent of 3" true duals. The 4" single comes the closest to this. To say that "the LS1 likes some back pressure" is just foolishness. There isn't a high performance motor on this planet that "likes some back pressure" and the LS1 is no different. If this was the case why wouldn't people with open headers just run a 2" diameter collector to create "some back pressure"?
My exhaust system (oversized according to the uneducated) consists of 3-1/2" true duals running into an "X" pipe and then 3" true duals to the rear of my car producing 426 RWHP & 400 RWTQ with a puny B1 cam. Surely there isn't anyone here that believes I would gain more peak HP with a smaller sized exhaust! Let's get real.
Go with the 4" mufflex, you won't be sorry!
My exhaust system (oversized according to the uneducated) consists of 3-1/2" true duals running into an "X" pipe and then 3" true duals to the rear of my car producing 426 RWHP & 400 RWTQ with a puny B1 cam. Surely there isn't anyone here that believes I would gain more peak HP with a smaller sized exhaust! Let's get real.
Go with the 4" mufflex, you won't be sorry!
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Re: Anyone make a 4inch catback or a bolt on Dual setup?
The only advantage I can think of to going with a smaller pipe is that the resulting higher exhaust velocity MIGHT induce a scavenging effect.
Other than that, John B is right... dual 3" pipes are pretty much dead on equivalent to a single 4.25" pipe. Since there aren't any 4.25" cat-backs available (that I know of), the 4" comes the closest. It's a hell of a big pipe, but if you want to run your exhaust out the back of the car on an F-body and you're looking for 400+ RWHP, it makes the most sense.
Other than that, John B is right... dual 3" pipes are pretty much dead on equivalent to a single 4.25" pipe. Since there aren't any 4.25" cat-backs available (that I know of), the 4" comes the closest. It's a hell of a big pipe, but if you want to run your exhaust out the back of the car on an F-body and you're looking for 400+ RWHP, it makes the most sense.
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Re: Anyone make a 4inch catback or a bolt on Dual setup?
John,
thanks for the shot of common sense in the midst of the over opinionated. a 4" mufflex is a great idea for a 380+ RWHP f-body, but duals are ideal. in a perfect world, a collector side 3" x-pipe w/3.5" after the x into some fairly free flowing mufflers, like a borla set, victor's, magnaflows, ect.. would be completely ideal. i've seen this setup on a few 350 rwhp cars run the same numbers on the dyno as when run open headers, just w/o the extra noise. the x adds to the scavenging effect and, after the x flow does not need to be inhibited at all.
the problem here, is that alot of us f-body guys like to take the 3" y-pipe as a standard for making power, when in actual reality, it's the crappiest idea i've ever seen used on any production V8, ever. in addressing the comment about "some backpressure" our cars need to breathe! some cars require backpressure to up the tq production because they are engineered at the factory to do so. however, a V8 15* headed motors dont require it. we're working around a top fuel inspired motor here. do those things need backpressure?
thanks for the shot of common sense in the midst of the over opinionated. a 4" mufflex is a great idea for a 380+ RWHP f-body, but duals are ideal. in a perfect world, a collector side 3" x-pipe w/3.5" after the x into some fairly free flowing mufflers, like a borla set, victor's, magnaflows, ect.. would be completely ideal. i've seen this setup on a few 350 rwhp cars run the same numbers on the dyno as when run open headers, just w/o the extra noise. the x adds to the scavenging effect and, after the x flow does not need to be inhibited at all.
the problem here, is that alot of us f-body guys like to take the 3" y-pipe as a standard for making power, when in actual reality, it's the crappiest idea i've ever seen used on any production V8, ever. in addressing the comment about "some backpressure" our cars need to breathe! some cars require backpressure to up the tq production because they are engineered at the factory to do so. however, a V8 15* headed motors dont require it. we're working around a top fuel inspired motor here. do those things need backpressure?
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Re: Anyone make a 4inch catback or a bolt on Dual setup?
Great thread and great info I am pretty sure I am going to switch from a 3" y with electric cutout to a 3" X pipe setup. I think I should be happy and my fears of loosing HP are gone now. I doubt I would loose much.
If it sounds like the mustangs its not too loud for me either so I think I am sold on the idea.
If it sounds like the mustangs its not too loud for me either so I think I am sold on the idea.