Downpipe HP limits?
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From: Harford co. MD
Downpipe HP limits? How much HP will 4, 4.5, and 5" DP's support and not be a restriction? Trying to figure out if i merge 2 -3" downpipes what size would be best to dump them into i plan on making around 1200whp it will have a full exhaust but also a dump before the system.
That is the nice thing about dumping before, you can have a nice small, well fitting exhaust with mufflers out the back that is quiet, but be able to open for the smack down if u are using an automated cutout of some kind
My old PT88 5.3 setup I dyno'd 950 through a single 3.5" with a 6" case straight through Magnaflow. Open cutout off the 4" downpipe it gained 5hp. I always left it on from then on. My current setup with twin 3.5 full exhaust and straight through Vibrant mufflers at 1000whp gained nothing at the track taking it off.
On yours Id do 3" into 4" and put a 4" cutout near the end of the trans before it curves up over the crossmembers and then reduce it down to a nice quiet cat back. Doing twin 3" cut outs up at the turbo adds quite a bit of junk in the engine bay.
On yours Id do 3" into 4" and put a 4" cutout near the end of the trans before it curves up over the crossmembers and then reduce it down to a nice quiet cat back. Doing twin 3" cut outs up at the turbo adds quite a bit of junk in the engine bay.
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A single 4" downpipe shouldn't be a restriction until 1500whp or so depending on length/bends. There are guys making 2200+ through a single 5".
I doubt you'll have any issues with a 4 inch exhaust
I doubt you'll have any issues with a 4 inch exhaust
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The 4" would package better and i plan to tie it back in to the stock type Grand national exhaust which is oval like 3x6" then it goes to twin 3" pipes but i would put the dump before that so it will basically go twin 3" to single 4" back to twin 3".
