Long tubes vs. shorties
#41
07-08-2007, 11:30 AM
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RE: Long tubes vs. shorties
Hank- At this point, I think the whole backpressure debate will end when the internal cumbustion engine is no longer used as the primary means of personal transportation.
Whichmanifold are you running now?Please post up the results when you get it installed.
ORIGINAL: Bigschwerm
glad to see you like the long tubes when i mounted mine on my motor i hadsimilar results.....deff. what the motor was needing.....
now i want to get the dual plane intake from hughes mounted up then im going to the dyno.....
glad to see you like the long tubes when i mounted mine on my motor i hadsimilar results.....deff. what the motor was needing.....
now i want to get the dual plane intake from hughes mounted up then im going to the dyno.....
#42
07-08-2007, 12:06 PM
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RE: Long tubes vs. shorties
I'm going to be replace my entire exhaust here shortly and I want to make sure I have a good understanding of what a good exhaust system would be like. So after the headers and y pipe, it would be a good idea to run 3" to the cat and then from the cat to the muffler (still debating on whether or not I'm going to install a muffler) or striaght out use 2.5" pipe? Now would 3" tips have any effect on the exhaust flow? I'm guessing not really because it's all the way at the end. And because it was never really stated I think, which really is better...shorties or long necks? I was always thinking of doing shorties but now after reading mopowar's post about the improvement he's had, I'm thinking of long necks.
#43
07-08-2007, 01:25 PM
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RE: Long tubes vs. shorties
ORIGINAL: mopowar
Hank- At this point, I think the whole backpressure debate will end when the internal cumbustion engine is no longer used as the primary means of personal transportation.
Whichmanifold are you running now?Please post up the results when you get it installed.
Hank- At this point, I think the whole backpressure debate will end when the internal cumbustion engine is no longer used as the primary means of personal transportation.
ORIGINAL: Bigschwerm
glad to see you like the long tubes when i mounted mine on my motor i hadsimilar results.....deff. what the motor was needing.....
now i want to get the dual plane intake from hughes mounted up then im going to the dyno.....
glad to see you like the long tubes when i mounted mine on my motor i hadsimilar results.....deff. what the motor was needing.....
now i want to get the dual plane intake from hughes mounted up then im going to the dyno.....
#44
07-09-2007, 07:15 AM
RE: Long tubes vs. shorties
mopowar jokes that:
>Hank- At this point, I think the whole backpressure debate will end when the >internal cumbustion engine is no longer used as the primary means of >personal transportation.
Ya got that right!
Actually, I think the US Military should teach US Personel that when captured they should talk out loud about this backpressure vs torque issue constantly. Eventually their enemy guards will begin to debate the issue too....and eventually the guards will end up turning their weapons on each other...allowing our crafty heros a chance to escape!
>Hank- At this point, I think the whole backpressure debate will end when the >internal cumbustion engine is no longer used as the primary means of >personal transportation.
Ya got that right!
Actually, I think the US Military should teach US Personel that when captured they should talk out loud about this backpressure vs torque issue constantly. Eventually their enemy guards will begin to debate the issue too....and eventually the guards will end up turning their weapons on each other...allowing our crafty heros a chance to escape!
#45
07-09-2007, 08:31 AM
RE: Long tubes vs. shorties
ORIGINAL: HankL
mopowar jokes that:
>Hank- At this point, I think the whole backpressure debate will end when the >internal cumbustion engine is no longer used as the primary means of >personal transportation.
Ya got that right!
Actually, I think the US Military should teach US Personel that when captured they should talk out loud about this backpressure vs torque issue constantly. Eventually their enemy guards will begin to debate the issue too....and eventually the guards will end up turning their weapons on each other...allowing our crafty heros a chance to escape!
mopowar jokes that:
>Hank- At this point, I think the whole backpressure debate will end when the >internal cumbustion engine is no longer used as the primary means of >personal transportation.
Ya got that right!
Actually, I think the US Military should teach US Personel that when captured they should talk out loud about this backpressure vs torque issue constantly. Eventually their enemy guards will begin to debate the issue too....and eventually the guards will end up turning their weapons on each other...allowing our crafty heros a chance to escape!
im just going to add a slight bit more fuel to that fire real quick. I dont really care what any book or website says, all i know is anytime iv opened up exhaust too much iv lost torque, and if iv closed it in too much iv lost torque, either way though horsepower seems to stay the same. (4v 4.6 ford, 305 chevy, and 360 dodge, iv noticed it on all three)
#46
07-09-2007, 09:36 AM
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RE: Long tubes vs. shorties
ORIGINAL: HankL
mopowar jokes that:
>Hank- At this point, I think the whole backpressure debate will end when the >internal cumbustion engine is no longer used as the primary means of >personal transportation.
Ya got that right!
Actually, I think the US Military should teach US Personel that when captured they should talk out loud about this backpressure vs torque issue constantly. Eventually their enemy guards will begin to debate the issue too....and eventually the guards will end up turning their weapons on each other...allowing our crafty heros a chance to escape!
mopowar jokes that:
>Hank- At this point, I think the whole backpressure debate will end when the >internal cumbustion engine is no longer used as the primary means of >personal transportation.
Ya got that right!
Actually, I think the US Military should teach US Personel that when captured they should talk out loud about this backpressure vs torque issue constantly. Eventually their enemy guards will begin to debate the issue too....and eventually the guards will end up turning their weapons on each other...allowing our crafty heros a chance to escape!
im just going to add a slight bit more fuel to that fire real quick. I dont really care what any book or website says, all i know is anytime iv opened up exhaust too much iv lost torque, and if iv closed it in too much iv lost torque, either way though horsepower seems to stay the same. (4v 4.6 ford, 305 chevy, and 360 dodge, iv noticed it on all three)
"If, in fact, power does increase with increased exhaust back pressure, it is
most likely the air/fuel ratio and/or ignition timing that are no longer
optimal for the altered state of engine tune."
As far as I understand it, the argument for backpressure revolves around cylinder pressure. Backpressureleaves exhaust gas in the cylinder to be compressed at the top of the exhaust stroke, and in turn this compression should force the cylinder downduring the intake stroke. Theway I see it, there are two things about this that don't add up:
1) This compression and the backpressure itself are takingrobbing from the power stroke of another cylinder. Compression takes effort as does forcing exhaust gas out of the cylinder against pressure.
2) The a/f coming into the cylinderis going to mix with exhaust gas.
Please correct me if mt understanding of this is wrong.
From some ofthe reading that I've done (mostly while searching for emissions law stuff), I think that factory exhaust is designed for one thing- emissions. I think that the small y is designed to create heatso that the catalyst reaches it's burn-off temperature quickly, andthe y dump is designed to slow the exhaust gas so that the catalyst is more efficient.
#47
07-09-2007, 01:26 PM
RE: Long tubes vs. shorties
ORIGINAL: mopowar
Either turn thier weapons on each other, or be forced to spend all the ammo money on pschyciatric care.
Think this could be the reason?:
"If, in fact, power does increase with increased exhaust back pressure, it is
most likely the air/fuel ratio and/or ignition timing that are no longer
optimal for the altered state of engine tune."
As far as I understand it, the argument for backpressure revolves around cylinder pressure. Backpressureleaves exhaust gas in the cylinder to be compressed at the top of the exhaust stroke, and in turn this compression should force the cylinder downduring the intake stroke. Theway I see it, there are two things about this that don't add up:
1) This compression and the backpressure itself are takingrobbing from the power stroke of another cylinder. Compression takes effort as does forcing exhaust gas out of the cylinder against pressure.
2) The a/f coming into the cylinderis going to mix with exhaust gas.
Please correct me if mt understanding of this is wrong.
From some ofthe reading that I've done (mostly while searching for emissions law stuff), I think that factory exhaust is designed for one thing- emissions. I think that the small y is designed to create heatso that the catalyst reaches it's burn-off temperature quickly, andthe y dump is designed to slow the exhaust gas so that the catalyst is more efficient.
ORIGINAL: HankL
mopowar jokes that:
>Hank- At this point, I think the whole backpressure debate will end when the >internal cumbustion engine is no longer used as the primary means of >personal transportation.
Ya got that right!
Actually, I think the US Military should teach US Personel that when captured they should talk out loud about this backpressure vs torque issue constantly. Eventually their enemy guards will begin to debate the issue too....and eventually the guards will end up turning their weapons on each other...allowing our crafty heros a chance to escape!
mopowar jokes that:
>Hank- At this point, I think the whole backpressure debate will end when the >internal cumbustion engine is no longer used as the primary means of >personal transportation.
Ya got that right!
Actually, I think the US Military should teach US Personel that when captured they should talk out loud about this backpressure vs torque issue constantly. Eventually their enemy guards will begin to debate the issue too....and eventually the guards will end up turning their weapons on each other...allowing our crafty heros a chance to escape!
im just going to add a slight bit more fuel to that fire real quick. I dont really care what any book or website says, all i know is anytime iv opened up exhaust too much iv lost torque, and if iv closed it in too much iv lost torque, either way though horsepower seems to stay the same. (4v 4.6 ford, 305 chevy, and 360 dodge, iv noticed it on all three)
"If, in fact, power does increase with increased exhaust back pressure, it is
most likely the air/fuel ratio and/or ignition timing that are no longer
optimal for the altered state of engine tune."
As far as I understand it, the argument for backpressure revolves around cylinder pressure. Backpressureleaves exhaust gas in the cylinder to be compressed at the top of the exhaust stroke, and in turn this compression should force the cylinder downduring the intake stroke. Theway I see it, there are two things about this that don't add up:
1) This compression and the backpressure itself are takingrobbing from the power stroke of another cylinder. Compression takes effort as does forcing exhaust gas out of the cylinder against pressure.
2) The a/f coming into the cylinderis going to mix with exhaust gas.
Please correct me if mt understanding of this is wrong.
From some ofthe reading that I've done (mostly while searching for emissions law stuff), I think that factory exhaust is designed for one thing- emissions. I think that the small y is designed to create heatso that the catalyst reaches it's burn-off temperature quickly, andthe y dump is designed to slow the exhaust gas so that the catalyst is more efficient.
to answer #1, i think its not that it effects the other cylenders, but that it effects the next combustion cycle in that cylender. nothing scientific, thats just my guess.
to #2, a/f mixture always mixes with exhaust gasses, slightly. ( some gasses do not completly expell, though it would be optimal that they do, and egr if so equipped)
#48
07-09-2007, 02:39 PM
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RE: Long tubes vs. shorties
The guy at the shop said that I had wasted my money on shorties. To your point, at the time, it probably would have been better to redo the exhaust back from the manifolds. Although, in the stock manifold the pulses do collide right there after leaving the chamber.
1) Yes it's supposed to help that cylinder cycle, but it does so at the expense of the cylinder that is on it's power stroke.
2) I agree. The a/f is always going to mix with some exhaust gas. Less is better, and the more backpressure the more exhaust gas.
1) Yes it's supposed to help that cylinder cycle, but it does so at the expense of the cylinder that is on it's power stroke.
2) I agree. The a/f is always going to mix with some exhaust gas. Less is better, and the more backpressure the more exhaust gas.
#49
07-09-2007, 03:17 PM
#50
07-10-2007, 07:13 AM
RE: Long tubes vs. shorties
I don't believe that shorties are a 'waste'
I think nearly all headers give a 3-6% torque gain
with short degrees of overlap camshafts near 3%
and long duration overlap camshafts near 6%
The length of the primary pipe just determines
at what rpm this gain occurs
short = high rpm (which is fine for racing)
long = mid rpm
Since we are talking about trucks
my own opinion is that the torque gain
should be in the 1500 to 2500 rpm range
and this takes Tri-Y design
with "super long" primary lengths 42 to 55 inches long
which means custom headers.
I think nearly all headers give a 3-6% torque gain
with short degrees of overlap camshafts near 3%
and long duration overlap camshafts near 6%
The length of the primary pipe just determines
at what rpm this gain occurs
short = high rpm (which is fine for racing)
long = mid rpm
Since we are talking about trucks
my own opinion is that the torque gain
should be in the 1500 to 2500 rpm range
and this takes Tri-Y design
with "super long" primary lengths 42 to 55 inches long
which means custom headers.