Exhaust Question - Need advice

[KR4MC Steve]

I've been thinking about getting some exhaust pipe & clamping it to my exhaust tip with a clamp so I can slide it in and out some while my wife races the engine in neutral to check the effect.

Maybe I can find a magic point that would put the "loud point" about 5000-6000 rpm (which would let it sound off best when wound out in gears) and not a cruising drone issue.

Then .... finding the solution of getting this extra length in the exhaust system without the temporary pipe sticking out the back!!!

[theo]

Originally posted by KR4MC Steve
I read somewhere on the net awhile back about "exhaust resonance ( or droning).

It was an automotive engineering artical about exhaust.

It stated that this effect is a combination of engine rpm, pipe diameter & length.

The artical stated that the resonance point will most be affected by changing the length of the piping from exhaust port to exit tip.

By using the formula supplied, you could legthen (or shorten this distance 16 inches & move the resonance from 3000 to 5500 rpm.

This equates to 3 1/4 to 3/34 acoustic wavelenths or something like that.

That's gonna be difficult with the BTG system becouse the triple chambered resonator is in the middle of the car just behind de cat.
They use a little absortion material in the rear tips. I'm gonna try to make the more quiet baffles a little longer with an ectra piece of metal atached to them (more narrow) and put some absortion materials around the baffles.

Theo

[KR4MC Steve]

I forgot to mention that SHORTENING the total exhaust length the same 16" would have the same tuning effect.

I could probably do that with a exhaust exit right behind the left rear wheel facing outward (which the artical stated GM did on some of it's models to move "drone" frequency above redline on some of it's high performance louder exhaust systems.

I just don't care for that exit point on a PT unless it has functional lake pipes.

[coolZero]

Originally posted by KR4MC Steve
I forgot to mention that SHORTENING the total exhaust length the same 16" would have the same tuning effect.

I could probably do that with a exhaust exit right behind the left rear wheel facing outward (which the artical stated GM did on some of it's models to move "drone" frequency above redline on some of it's high performance louder exhaust systems.

I just don't care for that exit point on a PT unless it has functional lake pipes.

What about via a ground effect with an exhaust port? Like on a lot of Mustangs you see. I've seen this type of ground effect on the PT. Then you could for go the lake pipes. Now if you did this does the muffler then mount right after the cat (one into two) and then runing the pipe from way forward. I saw a PT that had a "Y" after the cat and two glass packs way up towards the front and real long pipes running to the rear. Would this then change/move the "drone" effect to the higher rpms?

[CHRUZIN]

Hmmm, this thread sounds a lot like the ram induction phenomena that was explained in this link:

http://www.chrysler300club.com/uniq/...aboutrams.html

Would changing the diameter of the exhaust help compensate for the length? I noticed that the turbo has a larger dia. exhaust than the non-turbo.

[CHRUZIN]

KR4MC Steve, do you remember where you saw that exhaust article?

[PTGT Redman]

I put the Mopar/ borla dual tip. Mine had a resonator down the main exhaust tunnel. Noted that was diff than the other borla's i've seen. Only prob i had was clunking when the exhaust got hot. turns out the muffle will shift 2 inches backward when it's hot and actually start knocking against the bumper frame. Put a small rubber adhesice block and now it's quite. Has a nice tone but hardly louder than OEM. (has any one else had this prob with the Mopar performance pipes?) By the way I checked every inch for fit. It only clunks when hot.

[KR4MC Steve]

I've got a zillion shortcuts in folders all over the hard drive to different stuff on the net. I am going to try to see if I saved the link or archive acrobat pages. If I find anything, I'll let yall know.
I know there was at least one formula containg length in feet and rpm. It is probably a lot like header tube formulas, and had to do with how many cylinders dumped into each pipe (ie: 4 and 8 cylinder engines with duals were the same and six cylinders were different.

Now, lets see if I can find that darn tech artical!!

[CHRUZIN]

Originally posted by PT Blueman
I put the Mopar/ borla dual tip.

Is that the single dual tip, or the dual single tip?

[Comedy Cruiser]

I've got the Dynamax too and at 3000 it's quite a roar and it is beginning to bug me.

Would adding a baffled exhaust tip help out? I've got an unbaffled squared off tip now.

Any advice would be helpful!

Thanks,
Going Deaf in Buffalo