Muffler replacement huge horsepower gains!

[mickmate]

I don't think powdercoat will handle the exhaust temperatures, I'm thinking you'll need ceramic. There's even a few good color choices for it, I listed the guy I use he has them on his site. Doug go to bed!

[767Jockey]

Originally Posted by mickmate

Doug go to bed!

You have email!

[vector1]

put a straight pipe on that is long as possible and see if you get the flutter, if yes, starting cutting off inches at a time till it quits, this would be your optimum length.

even if it doesn't flutter, you could cut to see what would happen.

[RedBarchetta]

Originally Posted by vector1

put a straight pipe on that is long as possible and see if you get the flutter, if yes, starting cutting off inches at a time till it quits, this would be your optimum length.

even if it doesn't flutter, you could cut to see what would happen.

Aren't you describing the procedure for optimizing the torque curve just aft of a header collector? Old drag racing tuning trick. Not sure how lengthening or reducing the straight pipe affects harmonics? I should have paid more attention in HS physics class.

There is definitely some level of turbulence that is causing the flap. But, again, only on deceleration and usually more prevalent below 2,000 rpm. Might be air crashing together under engine braking?

-Dean

[vector1]

Originally Posted by RedBarchetta

Aren't you describing the procedure for optimizing the torque curve just aft of a header collector? Old drag racing tuning trick. Not sure how lengthening or reducing the straight pipe affects harmonics? I should have paid more attention in HS physics class.

There is definitely some level of turbulence that is causing the flap. But, again, only on deceleration and usually more prevalent below 2,000 rpm. Might be air crashing together under engine braking?

-Dean

could you be thinking of crossover tube placement?

my jbl has the sound you're talking about also when cold sitting still, don't know if it is the cold clearance on the solid rollers or what. i think it is the sound of reversion though. here is some data from a program that figures the length of pipe, hth.

---- Primary Pipe's Harmonics ----
1st Harmonic = 131.8 inches long ... typically never used
2nd Harmonic = 50.0 inches long ... longest recommended
3rd Harmonic = 29.9 inches long ... highly recommended , best Torque Curve
4th Harmonic = 20.8 inches long ... shortest recommended
5th Harmonic = 15.7 inches long ... typically never used
6th Harmonic = 12.3 inches long ... typically never used
7th Harmonic = 10.0 inches long ... typically never used
8th Harmonic = 8.3 inches long ... typically never used

---- Collector's Harmonics (includes Intermediate, Muffler , TailPipe) ----
1st Harmonic = 137.5 inches long ... longest with Mufflers and TailPipes
2nd Harmonic = 68.7 inches long ... longest recommended with Mufflers
3rd Harmonic = 34.4 inches long ... more bottom-end Torque
4th Harmonic = 17.2 inches long ... highly recommended , best Torque Curve
5th Harmonic = 8.6 inches long ... reduced Torque , more top-end HP sometimes
6th Harmonic = 4.3 inches long ... reduced Torque , not recommended

[Nantucket427]

I have been looking for more Power from my FE and found alot more than I expected in the exhaust. I changed to a baseball roll thur. size from stock, Wow what a difference. Nick cut out the old muffler and welded in the new one. He sent it to the coater and everything went back together great

The sound is not bad until WOT then everyone runs for cover

[Richard Hudgins]

Vector1,

If you have the standard JBL headers and sidepipes they are:

Primaries:

3rd Harmonic = 31.6 inches long 1.75 Dia.

Collector:

3rd Harmonic = 33.6 inches long 3 inch Dia.

This was the best compromise that I could provide for the various 351 derivatives.

They are pretty close to your program numbers.

But of course not optimal.

[mickmate]

Sure it does, are Unique slip fit or flange? They will both be covered here.

[mickmate]

Looks like another Classic Chambered fan
just changed to CLassic Chambered mufflers
I'm ordering another set tomorrow. Two of these cars are close to running.

[mickmate]

Good news to report, two of the three recently installed sets of Classic Chambered have been fired up. Funnily enough it was literally within minutes of each other. They sound pretty good even running indoors with both sets. I got the opportunity to log on a few miles with a set of the 2.5" using the transisition cones both on entry and exit to the mufflers. I ran my kids around in the car and found them quite easy to hear and talk to while driving. I received several comments about how loud they were from outside the car, some were car guys that said awesome, others were whiny neighbours that question the legality of such noisy exhausts so take that for what it's worth. No need for earplugs and plenty of power though I can't comment on the before and after difference in power from them. The customer will probably weigh in on it.

[DocDirk]

I had my 533 BB Ford chassis dyno'd before and after changing from stock 1 7/8" ID baffles to 2 1/2" ID baffles and the result was a gain of almost 50 peak RWHP, and increased low end torque. I'll post the dyno graphs when I have them...should be today or tomorrow.

Regards!

Dirk