3 vs 4inch downpipe?
3 vs 4inch downpipe? I am purchasing a Huron turbo kit this winter and pairing it with a CT43 with the billet 7475 with huron 82/75 (recommended by Huron). I am unsure what everyone would recommend for a downpipe size? I will be around 7-750rwhp with the build and psi estimates.
I am planning to run whatever size downpipe all the way back to bumper and split at the very end into 2 after the rearend. Ex. 3inch downpipe connected to straight 3 inch back over rear connected to 2pipes that split into where the exhaust exits the vehicle like normal to look normal. Or the same thing only with 4inch pipe. Which would be a better choice and why?
I am planning to run whatever size downpipe all the way back to bumper and split at the very end into 2 after the rearend. Ex. 3inch downpipe connected to straight 3 inch back over rear connected to 2pipes that split into where the exhaust exits the vehicle like normal to look normal. Or the same thing only with 4inch pipe. Which would be a better choice and why?
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Joined: Jun 2013
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From: Moose Jaw SK, Canada
Lots of threads on this. But at that power level you shouldn't see a difference. I personally went with a 4 inch *s475, Huron kit* made custom motor mounts and ran it hugged to the block passengers side. I thought I'd plan ahead.
If you don't plan on super crazy horsepower I don't think a 3" DP will hold you back any.
If you don't plan on super crazy horsepower I don't think a 3" DP will hold you back any.
Is there any difference in sound, lowend and/or highend power? I have some friends who say no exhaust is best exhaust and run 4inch downpipes all day with their builds ranging from hondas to mustangs, then I have some saying 3inch is better for a v8 with less than 1000hp but I don't know the differences lol. Like if the 4inch doesn't hurt power levels.. just makes the car louder, or more to breath for in future if I want more power... wouldn't it be better all around to just do 4inch straight back?
Responded to your emails with this question. The 3" downpipe in the kit with this turbo set-up will support more than your goals and fit without any modification to anything!
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From: Joliet,IL and Las Vegas 50/50
I ran a 3" dp well into the upper 9's @140mph. I was beginning to choke on it a bit and went 4" more recently but the 3" is a nice size to get you to your goals without having to go with a turbo kmember or bumper exhaust
Yea I'm probably sticking with the normal 3inch downpipe from huron when I order. May wind up going into a 4inch straight back exhaust from the downpipe back, not sure yet. I have access to both 3 and 4inch piping whenever I need, so if it doesn't hurt anything, I figured might as well.
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I am kind of torn on this subject right now as well. I have a forged LS1 with a turbonetics 7875 BB, which has a 3" v-band outlet. I already bought a 3-4" adapter, and was planning on a 4 inch downpipe to an exhaust cutout, and then 3" back from there for lower boost.
I would REALLY like to skip going the 4" DP route because it is going to be a major bitch to plumbing around my swap. I am shooting for 800whp, do you guys think a 3 inch DP with a cutout right there will not hold me back?
Sorry for thread jack, hopefully this is constructive for you as well
I would REALLY like to skip going the 4" DP route because it is going to be a major bitch to plumbing around my swap. I am shooting for 800whp, do you guys think a 3 inch DP with a cutout right there will not hold me back?
Sorry for thread jack, hopefully this is constructive for you as well
You could look at round-oval-round plumbing. I have a 240sx and saw a turbo LS1 that did it that way (from turbo back) so that the oval ran by manifolds and down near the firewall. Sorry can't add input on the feasibility of the 3" DP.