One for the exhaust nuts: custom exhaust idea

[Cogito Ergo Zoom]

I was under the MPV again today with a copy of a JEGs catalog taking some measurements (I just reread that...sounds a bit perverse!), and I have an idea I'm kicking around.

First, let me preface this by saying I'd remove the OEM factory exhaust system as intact as possible, so I can reuse it if needed (I might have to add a couple of flanges to do this.) But, here's what I think might work:

(a) Cut off the curved 2" outlet pipes directly behind each cat, thus removing the restrictive factory "Y" pipe/collector completely.
(b) Weld 2.25" straight pipes (one would be shorter than the other) to each cat and run them to a Flowmaster P/N Y214300A 2.25" dual in/3" single outlet Y-collector (cost: $38 ).
(c) The 3" outlet side might need to be trimmed back a bit. Add a 3-bolt header flange to the 3" outlet ($10 ), gasket ($4) and hardware.
(d) From this flange, use a JEGs P/N 30004 3" to 2.5" bolt-on reducer (cost: $18 )
(e) Using the factory pipe as a template, weld a section of 2.5" aluminized pipe from the new reducer to a new muffler (figure $20 parts & labor for this piece).
(f) Mount a Dynomax P/N 17749 2.5" offset in/2.5" offset out Hemi Super Turbo muffler (cost $43) in place of the factory muffler. Yes, it would fit under there; in fact, it's just a little shorter length-wise and isn't quite as tall as the OEM muffler. The muffler would be slip-fit attached on both the inlet and outlet sides using u-bolt exhaust clamps for easy removal.
(g) Fab a section of 2.5" tailpipe to go over the axle, stopping at about the same point where the factory resonator is bolted on. This piece might run $30 parts & labor.

STOP HERE and fire the motor up, and hear how it sounds. Drive around a bit to check the drone factor.

If ok, complete tailpipe such that it exits in the stock location under the GFX rear valance. If not, add $20 straight through resonator. Add tip that looks as close to the factory chrome one as possible. Garnish with parsley, and serve.

Total cost: $160-180, depending.
Total HP increase: with the cone I already have installed, maybe 8-10-ish

Whaddya all think?

Morgan

[javadoc]

Doesn't sound too shabby. With the 3.0L motor, I bet you could get away with 2.5" piping. 2.25" may be just right for the 2.5L motor though. Or go for the gusto w/ 3.0" piping! I think you'd still have decent exhaust gas velocity.

Mandrel bends... must have mandrel bends.

[papabear]

This sounds great. I would've just taken your suggestion and gone to my locale exhaust shop, but I did my taxes this weekend and found that my wife and I will be paying for the first time since we were young and single and still teenagers!

It seems we had miscalculated our withholdings this past year and never knew that each of us had overstated until now. We were always so happy that our pay checks had increased, but didn't realize that both of us had changed our W4. Anyway, no toys for the distant future!

[gizmo]

I am taking notes. I wanted to `remove` the resonator, jusy to check if it would improve sound, bit weather forbids it (-15C average).
Morgan, next time you are under the MPV, would you take measurements for dual pipes AFTER the mufler (I would have a body repairman carve the left side of my GFX bumper to accomodate the extra pipe).
Also, would you consider the Hemi Super Turbo a suitable mufler to resist salt & snow, hot & cold ?
Thanks,

Denis

[Cogito Ergo Zoom]

Gizmo/Denis,

I toyed with the idea of true 2.25" duals from the cats back but it looked to me that the space between the fuel tank and spare tire well wouldn't allow enough room to avoid exhaust rattles, plus there are various lines routed above the OEM pipe. That, and I didn't want to start cutting into the rear valance. In your case the trick would be to find a long enough single offset inlet/dual outlet muffler to accomplish the look you're trying to attain and still be quiet (I'm thinking of those custom mufflers like Gibson that you see on Tahoes and Expeditions, but not as loud.) I had a pair of Super Turbos on a couple of cars and they survived the snow and rain of Washington state just fine. The last pair of STs lasted 6 years. 'Course, we don't salt the roads on this Coast!

On another note, I visited your beautiful city several times back in the early 80's. I was the only one in a music group from California that could speak passable French! One of my fondest memories is crossing a bridge on a bus and seeing the lights of Montreal at 2AM. Man, that was romantic!

[novalight]

hehe thread revival

https://youtu.be/oNoyzBi3oTs

[aha]

movalight - it sounds good!

[Mazdaze]

sounds great

[novalight]

And so it is finally finished after more then a decade, 22" glasspack inplace of center resonator and 18" x3" Tip basically now a straight pipe

https://youtu.be/rdBgHE009DI