HUH?? I got a 5.0,not a Hoover90mustangGT said:
The kinks allow it to flow better? Dude,put down the pipe and walk away!!T-Moss or M.Yount,or exhaust guru's come in
- Thread starter willys1
- Start date
The kinks allow it to flow better? Dude,put down the pipe and walk away!!
Michael Yount said:
I added more things by the time I hit the track next. Not all at once with the headers. The headers went on seperate. I felt a slight difference. Something noticeable. I have a self-proclaimed good SOTP feel. My friends always come to me or ask me what this or that car will run after I ride in it. I can tune out the smoothness or harshness of the acceleration and actually "feel" a difference. In my eyes...I gained...and in my feel...I gained. These are equal length headers...those stock ones were way to small and seeminly restrictive.
I see it as pretty reliable in my case...not others...because that is them...not me. I have been very accurate with my predictions and "feelings" when I compared them at the track. I keep calling it like the Babe
Jason, I'm with you on this one
04sleeper
Founding Member
David,
With your setup I would go with the 1 5/8" as well. My car having stock unported heads is what I was refering to.
Billy,
Sounds good, just give me a call whenever is good.
Kevin
With your setup I would go with the 1 5/8" as well. My car having stock unported heads is what I was refering to.
Billy,
Sounds good, just give me a call whenever is good.
Kevin
Michael Yount
Mustang Master
"I can tune out the smoothness or harshness of the acceleration and actually "feel" a difference. In my eyes...I gained...and in my feel...I gained."
Using the Force no doubt....
Using the Force no doubt....
willys1 said:HUH?? I got a 5.0,not a Hoover
No reefer here, I was posting that to prove scavaging and how the header runners act like the ports on the pnumatic vaccume, the gas leaving one runner causes an area of negative pressure pulling gas out of the other runner. I didn't say anything about flow except how scavanging will increase flow.
An bodies of equal amount of mass pushed one through a larger hole and a smaller hole can be done, but the mass is going to have to move much faster through the smaller hole. More speed equals more scavaging.
At a certian point the volume of gas overwhelms the size of the pipe it has to flow through and backs up know as backpressure. Anyone who tells you that backpressure is important doesn't know what they are talking about.
Michael Yount
Mustang Master
90gt - do a google on exhaust scavenging - your terminology is either off, or you're mistaken. Scavenging occurs because of a pressure wave that bounces back up the primary - timed in a way that it hits the head and bounces back down the primary just when the next exhaust pulse is leaving the same port. That bounced pressure wave helps accelerate the flow of exhaust. The exhaust flow moves at an entirely different, and much slower, velocity than the pressure wave moves at.
For V8's, pressure wave scavenging is much more effective at assisting exhaust flow and (yes) even helping to fill the cylinder during overlap (when both intake and exhaust valves are open) when 1) long tubes are involved - the tuned length of the primary is around 24-36"; 2) an 8"-12" long collector of around 3" diameter is present - it's this expansion of volume (from the primary size to the collector size) that partially 'kills' the pressure wave, and bounces it back up the primary to aid the next pulse. The velocity of the exhaust flow is quite slow compared to the velocity of the pressure waves - which travel at the speed of sound.
For V8's, pressure wave scavenging is much more effective at assisting exhaust flow and (yes) even helping to fill the cylinder during overlap (when both intake and exhaust valves are open) when 1) long tubes are involved - the tuned length of the primary is around 24-36"; 2) an 8"-12" long collector of around 3" diameter is present - it's this expansion of volume (from the primary size to the collector size) that partially 'kills' the pressure wave, and bounces it back up the primary to aid the next pulse. The velocity of the exhaust flow is quite slow compared to the velocity of the pressure waves - which travel at the speed of sound.
dvs bullet
New Member
90mustangGT said:
smaller pipes create more pressure, more pressure equals higher velocity ( speed of gases) this speed coming from one tube on a header creates a venturi affect pulling remaining gases in other tubes out ( like a carberator ). What some people don't get is that ther is a certain point that you shouldn't go past to to keep up velocity. What I did was 1 5/8 shorties 2 1/2 h pipe and then went down to 2 1/4 tails, when you get past the muffler the gases cool and shrink loosing presure and velocity, you shrink down a size after the mufflers to keep the gases moving faster
dvs bullet
New Member
Sorry I don't have time to wiegh in here as I am on the raod moving my son from Portland Oregon back to St Louis. We are taking out time through the scenic routes of the rockies.
Selecting the right exhaust SYSTEM (not one piece) is not that simple deal. Most guys go too big too fast, but some combos can take advantage of the increased system cross section without loosing a lot. In general, a 1 1/2" works well on a 302 and 1 5/8" work well on a 347. I've seen it happen time after time over the years on dyno comparison tests. Some combos do show 1 5/8" being better on a 302 but they are less likely. Like anything thing else - it depnds on the combo you choose to use it with. Most people rely on the SOTP which IS pretty unreliable. Sorry I can't be more helpful, but in the end it's an educated guess.
Selecting the right exhaust SYSTEM (not one piece) is not that simple deal. Most guys go too big too fast, but some combos can take advantage of the increased system cross section without loosing a lot. In general, a 1 1/2" works well on a 302 and 1 5/8" work well on a 347. I've seen it happen time after time over the years on dyno comparison tests. Some combos do show 1 5/8" being better on a 302 but they are less likely. Like anything thing else - it depnds on the combo you choose to use it with. Most people rely on the SOTP which IS pretty unreliable. Sorry I can't be more helpful, but in the end it's an educated guess.
I've seen similar results with headers and H/X pipes on stock motors, and was surprised how those kinked up messes Ford calls a header actually work..lol
With a ported stock head we have not seen any losses or major gains with a 1.5" shorty, to me they are a waste of money. Wait till you add more mods and swap to a 1.625" shorty or long tube.
Kevin How's the search for a new car coming?
With a ported stock head we have not seen any losses or major gains with a 1.5" shorty, to me they are a waste of money. Wait till you add more mods and swap to a 1.625" shorty or long tube.
Kevin How's the search for a new car coming?
Michael Yount
Mustang Master
"Kevin How's the search for a new car coming?"
Yes - inquiring minds want to know if the next "sleeper" has arrived....
Yes - inquiring minds want to know if the next "sleeper" has arrived....
04sleeper
Founding Member
No, it has not arrived yet. 
I have been looking around pricing some 03's and 04's. I have been kind of working on my garage right now trying to get it ready for the new car. Along with working on everything else in the new house. It's been just enough to keep up with right now and I have been traveling a lot with work so it doesn't help.
Here is what I have been working on.
Before:
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After:
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View attachment 512318
View attachment 512320
Future:
View attachment 512322
I have been looking around pricing some 03's and 04's. I have been kind of working on my garage right now trying to get it ready for the new car. Along with working on everything else in the new house. It's been just enough to keep up with right now and I have been traveling a lot with work so it doesn't help.
Here is what I have been working on.
Before:
View attachment 512314
After:
View attachment 512316
View attachment 512318
View attachment 512320
Future:
View attachment 512322
Michael Yount
Mustang Master
Lookin good Kevin ,,Hey Tom if you have time do yourself a favor and stop in Telluride for lunch,or over night if possible Thanks guys,I think Im gonna change my FMS unequal shorties for some equal lenth shorties,a catted X-pipe,and keep my Bassani cat back on..I have a T-Moss lower I was gonna use but I just ran across a cheap GT-40 intake,its real tempting 
,,Hey Tom if you have time do yourself a favor and stop in Telluride for lunch,or over night if possible Thanks guys,I think Im gonna change my FMS unequal shorties for some equal lenth shorties,a catted X-pipe,and keep my Bassani cat back on..I have a T-Moss lower I was gonna use but I just ran across a cheap GT-40 intake,its real tempting Similar threads
