Can a 5" down pipe clear the firewall?
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5" Exhaust Homemade down pipe
Currently i have a 3" downpipe into my 5" pipe. I have a 3" to 5" adapter so if i back that up where i cut the stock downpipe off could i then run a 5" pip from there back or will this hurt performance? Just going for sound but if its not worth it then i wont mess with it
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a 5" pipe can clear the firewall, but it's not necessary... especially with an HX35
There will be no negative affect on performance. A diesel engine runs on compression and therefore does not need any back-pressure. The more you open it up the better.
As for installing a custom 5" downpipe, I think it could be done but it will either be VERY close going underneath the firewall and between the bell housing and the frame. This is why most aftermarket kits come with a 4" downpipe that connects to a 5" exhaust system. Also, it has been proven that a 5" does no benefit over a 4" exhaust until you get way up in horsepower. If I were you I would simply make a custom 4" downpipe, or you can always try to purchase on from a vendor.
As for installing a custom 5" downpipe, I think it could be done but it will either be VERY close going underneath the firewall and between the bell housing and the frame. This is why most aftermarket kits come with a 4" downpipe that connects to a 5" exhaust system. Also, it has been proven that a 5" does no benefit over a 4" exhaust until you get way up in horsepower. If I were you I would simply make a custom 4" downpipe, or you can always try to purchase on from a vendor.
The fact that they "run on compression" has nothing to do with why they don't need back pressure.
But bigger isn't always better. At lower volume flow /power levels, a larger exhaust diameter will cause the gas to stall and eddy and actually cause more back pressure than a smaller diameter pipe.
But bigger isn't always better. At lower volume flow /power levels, a larger exhaust diameter will cause the gas to stall and eddy and actually cause more back pressure than a smaller diameter pipe.
See commentsThe fact that they "run on compression" has nothing to do with why they don't need back pressure.
Running on compression allows the diesel engine to function without having a consistent fuel to air ratio (like a gasser needs). The back pressure affects this mixture on a gasser engine and is therefore necessary for the engine to function properly. On a diesel the back pressure plays no part in how the engine runs because the fuel to air ratio does not matter (to an extent).
But bigger isn't always better. At lower volume flow /power levels, a larger exhaust diameter will cause the gas to stall and eddy and actually cause more back pressure than a smaller diameter pipe.
I am sorry but this is just simply wrong unless the larger pipe is followed up by another smaller diameter pipe. If it is 5" straight out then it will flow better in every scenario than a 4" or 3". If it were a 4" into a 5" and then back into a 4" then it could have a negative affect on flow. Try exhaling slowly through a small straw and see how long it takes you to deplete your lungs...now try exhaling slowly through a 1" PVC pipe and time it. If you truly put the same effort into exhaling using each then the 1" PVC pipe will deplete your lungs quicker.
no engine wants backpressure
and exhaust systems have bends in them
do some data logging on a mild truck with a little HX35 with 4" and then 5" exhaust and get back with me on the initial spool-up results
and exhaust systems have bends in them
do some data logging on a mild truck with a little HX35 with 4" and then 5" exhaust and get back with me on the initial spool-up results
This is 100% correct. Needing backpressure on a gasser is a myth, a popular one at that. Scavenging is what you want.no engine wants backpressure
I have a 4in downpipe and its close to the firewall.
Is this a redundant question? Cause I actually don't know. Would a 4" allow the hx35 to spool faster?no engine wants backpressure
and exhaust systems have bends in them
do some data logging on a mild truck with a little HX35 with 4" and then 5" exhaust and get back with me on the initial spool-up results
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