ptuomov

I don't know what I am talking about, but just thinking about this in terms of logic, this will identify the average high static pressure (and therefore high temperature) area. That should be a point at which you can terminate the collector either by just cutting it or by adding a cross-over.

The one caveat for this is that I've only heard of that method being used on a dyno or on a drag strip. If you the car isn't being used at the power band that is being maximized (most street cars fit this definition), then the test will optimize for the rpm that is actually used and not the rpm that the user might want to maximize.

You probably can't hear the drone because the exhaust is so loud! ;-)

Magnaflow seems to be the best bang for the buck on mufflers. I've got those waiting to go in as a part of the next exhaust.

If you spend $40 on pipemax, it will tell you how long it should be.

For 5500 rpm effect and used power band of 3500-6000, you probably want to go shorter than 24", more like 18". But that's an uninformed guess.

Pipemax will tell you. 3" collector sounds pretty large and will probably not maximize the tuning effect for this engine. But who knows.

A warning: If you neck down the exhaust at any point other than the primary pipe merge, you probably aren't maximizing the tune and the constriction will reflect the same sign wave upstream the exhaust. I think (but do not know) that one would be better off say with two 2.5" collectors merging to a single 3.5" pipe than two 3" collectors merging to a single 3" pipe.

Assuming that the cat has an expansion in cross-sectional area, I would consider either cat as close to the Y/X as possible or collector length from the Y/X (with 18" collector to X/Y and another 18" to the cat).

I am all v-bands now on the exhaust. Even those sometimes seize, but boy are they easier than bolted flanges.

jshuberg

I'm assuming that the location of the muffler is less important for power/torque, but more important for sound. I'm guessing that a few feet in from the tips, maybe just aft of the cat would be the best place for it sound-wise.

FBIII

Ptuomov:
I don't know what I am talking about, but just thinking about this in terms of logic, this will identify the average high static pressure (and therefore high temperature) area. That should be a point at which you can terminate the collector either by just cutting it or by adding a cross-over.

The one caveat for this is that I've only heard of that method being used on a dyno or on a drag strip. If you the car isn't being used at the power band that is being maximized (most street cars fit this definition), then the test will optimize for the rpm that is actually used and not the rpm that the user might want to maximize.

Great extrapolating on your part. They recommend doing the paint thing with the engine at or near its maximum torque rpm.

ptuomov

Depends on the muffler. If it's glass pack muffler, the location and length are relevant from pulse tuning point of view. Tightly packed glasspack will look almost like a straight pipe to the pulses. If it's a chamber muffler or a resonator/terminator box, location is very important from pulse tuning point of view. A chamber muffler will look like the pipe end to the pulses.

See here:



Generally, you don't usually want to put many similar type muffler in series, because they produce self-generated noise that is similar. Mufflers don't just subtract, they also add!

Ducman82

here is how mine turned out....... the "y" is a little off, but works well....

FBIII

Thanks for the pics. Very helpful in the fabrication needed after the transmission crossmember.

jshuberg

OK, so here's the plan:

MSDS Headers to 2.5" Y-pipe with 3" output to Random technologies cat to resonator (??) and Magnaflow 14" muffler. The shop I'm having do the work has offered to prototype up a few different muffler/resonator configurations, and let me choose the one that I think sounds best. I really like that idea

Headers and cat have been ordered. I'm having them ceramic coated so it will likely be a few weeks before I get them. Once everything is done I'll post dyno results.

Thanks everyone for the help!!

123quattro

I have that same 14" Magnaflow muffler on my 200 20v. It sits in the bumper. That car has fairly noticeable drone. We did the same setup on a buddy's Supra and it droned as well. I think the key is to get a few feet of pipe after the muffler.

My 928 is actually fairly quiet at highway speeds. It's odd. It will get loud if you roll on the throttle, but cruising is totally acceptable even for women. My wife and daughter ride in the car all the time. It's what I daily all summer. A baby seat in the back gets you some funny looks.

Ducman82

i had Zero drone while driving from ohio to CA...