exaust and back presure
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exaust and back presure
If someone feels i should be directed to another feel free to do so
so right now i have a bone stock 351W with long tube headers and a 2.5'' to a flowmaster super 44 and end on the passager side
i would like to run a larger diameter as i have heard that it can provide a deeper note to the exhaust sound i was tinking of going with the flow master 50 HD seiris 4.00'' center in center out
Flowmaster 50 SERIES HD HEAVY DUTY MUFFLER - *FREE GROUND SHIPPING
i have always heard that you can loose power if u run too large of a diameter i know 4'' is more for diesel and i also know that this muffler is supposed to be for big block Hemi's
so to summ up here is the big question 1)is 4" too big
2) should i bee looking and a different muffler
3) how much power would i loose with such a large diameter on a small block
so right now i have a bone stock 351W with long tube headers and a 2.5'' to a flowmaster super 44 and end on the passager side
i would like to run a larger diameter as i have heard that it can provide a deeper note to the exhaust sound i was tinking of going with the flow master 50 HD seiris 4.00'' center in center out
Flowmaster 50 SERIES HD HEAVY DUTY MUFFLER - *FREE GROUND SHIPPING
i have always heard that you can loose power if u run too large of a diameter i know 4'' is more for diesel and i also know that this muffler is supposed to be for big block Hemi's
so to summ up here is the big question 1)is 4" too big
2) should i bee looking and a different muffler
3) how much power would i loose with such a large diameter on a small block
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4 inch is way to big, as for muffler its all in what you like sound wise if you ask me. 3 inch is the max I would go with a single pipe on a small block engine and that's only if I plan on doing a good bit of high rpm flat footing but it will give a slightly deeper sound from my experience. Also for the record backpressure is a myth, what you want out of a good exhaust system is flow.
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4 inch is way to big, as for muffler its all in what you like sound wise if you ask me. 3 inch is the max I would go with a single pipe on a small block engine and that's only if I plan on doing a good bit of high rpm flat footing but it will give a slightly deeper sound from my experience. Also for the record backpressure is a myth, what you want out of a good exhaust system is flow.
What specifically the 4 too is it just un nessasary
For a small block
FTE Legend
Joined: Jun 2006
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From: Ottawa, Ontario
It's all about exhaust gas velocity and this is what people confuse with back pressure which is a totally meaningless term. The internal combustion engine is an air pump so anything that increases airflow will also increase horsepower, but if the exhaust tubing is too big exhaust gasses lose momentum(speed) which reduces the cylinder scavenging effect(exhaust gas rushing out of a cylinder help pull in a fresh charge) at lower rpms and that impacts low rpm torque. Every engine will have an ideal exhaust tubing size, these old motors aren't particularly powerful.. about 200hp, so a 2.5" to 3" single exhaust will allow enough airflow to reach peak power and is small enough to maintain exhaust gas velocity at lower rpms. Bottom line it's all about finding a good balance between the two aspects, too much of one hurts the other.
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It's all about exhaust gas velocity and this is what people confuse with back pressure which is a totally meaningless term. The internal combustion engine is an air pump so anything that increases airflow will also increase horsepower, but if the exhaust tubing is too big exhaust gasses lose momentum(speed) which reduces the cylinder scavenging effect(exhaust gas rushing out of a cylinder help pull in a fresh charge) at lower rpms and that impacts low rpm torque. Every engine will have an ideal exhaust tubing size, these old motors aren't particularly powerful.. about 200hp, so a 2.5" to 3" single exhaust will allow enough airflow to reach peak power and is small enough to maintain exhaust gas velocity at lower rpms. Bottom line it's all about finding a good balance between the two aspects, too much of one hurts the other.
Engine speed is also a factor. My car, with a little old 302 has dual 2.5" all the way back, it also regularly sees 4000-5000 RPM, my 460 in my truck also runs dual 2.5 all the way back, and while it is much larger, it rarely gets spun faster than about 2500.
For a 351, in a pickup a 3" single is all you'd ever need. If you want a deeper tone look at different mufflers, maybe Dynomax or Magnaflow.
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