How far to rev this 273 commando build

[toolmanmike]

[QUOTE="stroker402
mufflers are dumped in front of axle .[/QUOTE]

Tail pipes can make a big difference. BIG

 

[stroker402]

[QUOTE="stroker402
mufflers are dumped in front of axle .

Tail pipes can make a big difference. BIG[/QUOTE]

I had installed tailpipes when I had the flomasters 40's on ...... It got so rappy............. I took the tailpipes back off.
I think the only thing that is going to quiet this beast up is a x or h pipe.

 

[toolmanmike]

Tail pipes can make a big difference. BIG

I had installed tailpipes when I had the flomasters 40's on ...... It got so rappy............. I took the tailpipes back off.
I think the only thing that is going to quiet this beast up is a x or h pipe.[/QUOTE]


That will help as well. Tail pipes mellowed exhaust long before x and H pipes were popular though. Just sayin'

 

[AJ/FormS]

My Barracuda has those mufflers with TTI dual 3s out to the back and their mild turn-downs. And no Crossover. I get a lot of compliments on the sound. This is just a 367@10.9Scr running about 180psi cylinder pressure with a 230* cam. They also sound good from inside the car, very mellow until about 4000, then screaming ever louder on the the way to 7000. But it's a pleasant screaming. At least from inside the car.lol.

 

[stroker402]

my set up is 2.5" - header collector diameter , 2.5" head pipes and 2.5" in and out ultraflos . This 273 commando makes more noise than my 402 stroker did with 3" to the axle. same muffler brand ultraflos. that was a 9.1 engine.......... 360 magnum crate with the RT heads . I think "compression" is what makes the exhaust sound so different between the two.

 

[AJ/FormS]

my set up is 2.5" - header collector diameter , 2.5" head pipes and 2.5" in and out ultraflos . This 273 commando makes more noise than my 402 stroker did with 3" to the axle. same muffler brand ultraflos. that was a 9.1 engine.......... 360 magnum crate with the RT heads . I think "compression" is what makes the exhaust sound so different between the two.

I think you're right about the compression.
I ran my 367 with three different cams and about the same 180psi cylinder pressure. And it sounded about the same with each combo.
But when I put the smogger-teen in for winter at maybe 130psi, then they were a bit more mellow, until she went to WOT, then the teener was practically quiet compared to the 360. So, it's probably a combination of; the different volume of gasses being processed, and the pressure of those gasses, and the rate at which they are coming thru.
I really liked the mellow-teener at WOT, together with it's moaning TQ carb.
I also liked both of them from 1800 to 3600, in too high a gear (manual trans)and then hammered to just before she breaks loose. As she begins to work, the pipes sing. I think that sweetspot belongs to the pipes, cuz all of them sounded really good in that range.

 

[stroker402]

I think you're right about the compression.
I ran my 367 with three different cams and about the same 180psi cylinder pressure. And it sounded about the same with each combo.
But when I put the smogger-teen in for winter at maybe 130psi, then they were a bit more mellow, until she went to WOT, then the teener was practically quiet compared to the 360. So, it's probably a combination of; the different volume of gasses being processed, and the pressure of those gasses, and the rate at which they are coming thru.
I really liked the mellow-teener at WOT, together with it's moaning TQ carb.
I also liked both of them from 1800 to 3600, in too high a gear (manual trans)and then hammered to just before she breaks loose. As she begins to work, the pipes sing. I think that sweetspot belongs to the pipes, cuz both of them sounded really good in that range.

Yep..... more compression = More POP.

 

[273]

It's over my head, Steve, but it has something to do with physics. Every time on every dyno run torque and HP always intersect at 5250. I don't know why.

Steve, I found this. I got lost pretty quickly, but maybe it will help. lol

Why does hp and tq crossover at the same point always? - Power and Drivetrain

Torque x rpm / 5252 = Hp
Torque x 5252 / 5252 = Hp

Cause at 5252 rpm's the rpm and the constant of 5252 in the formula cancels each other out. The cross over has no significance in the power curve of the engine.

If measured in Kw you'll have a different cross over point, you could figure out how much work you can do in a minute and come up Rob power formula Rp which would have a different cross over point but doesn't matter if you use Kw Hp or Rp they will all have the same curve and be mathematically comparable to each other.

 

[toolmanmike]

Cause at 5252 rpm's the rpm and the constant of 5252 in the formula cancels each other out. The cross over has no significance in the power curve of the engine.

If measured in Kw you'll have a different cross over point, you could figure out how much work you can do in a minute and come up Rob power formula Rp which would have a different cross over point but doesn't matter if you use Kw Hp or Rp they will all have the same curve and be mathematically comparable to each other.

Exactly. Torque is measured on a dyno. Horsepower is calculated.

 

[273]

Exactly. Torque is measured on a dyno. Horsepower is calculated.

Yes the dyno measures torque @ rpm and hp is the mathematical representation of the combined ability of the two.

 

[AJ/FormS]

But IMO the two curves, with same scales, on a common graph, tell the story at both ends of their respective curves.
As in; from the power curve alone, it is difficult to see what is going on at low rpm, and from the torque curve alone, it ia sometimes difficult to predict what will happen when a certain change is contemplated.
Either curve can be created from a missing curve; with a simple calculator, it just takes a few minutes. If you really want to see the curves in action, convert the graphs to ftlbs or hp to the road, in each gear and graph that! And then....

 

[273]

But IMO the two curves, with same scales, on a common graph, tell the story at both ends of their respective curves.
As in; from the power curve alone, it is difficult to see what is going on at low rpm, and from the torque curve alone, it ia sometimes difficult to predict what will happen when a certain change is contemplated.
Either curve can be created from a missing curve; with a simple calculator, it just takes a few minutes. If you really want to see the curves in action, convert the graphs to ftlbs or hp, to the road in each gear and graph that! And then....

Definitely the torque curve is better at visually representing whats going on the area under the power curve.