Single exhaust, or dual?

[Triplegreen500]

I know...but this car is an unrestored survivor and is NOT a "race car".

70 Charger 500, factory a/c, # match 318/2, bone stock. A904, bone stock. 2.74(?) rear gears in the open 8.25 rear. It's a cruiser. Original sheetmetal with near-original paint (one repaint, I think late 70s, presumably paint fade - FL car its whole life). Original interior. Original 14" wheels with full wheelcovers. Original vinyl top. ALL stock, except for some LED lights I put in the dash; HID H4 conversion headlights; and potentially a front disc brake conversion down the road.

Currently it has some cobbled-together, uneven, DRONING dual exhaust with flowmasters on it. Needs to go.

My debate? Accurate Exhaust single system like stock? Or one of their dual systems?

From what I can tell, this car would have had a single exhaust stock. I don't drive it for performance; I don't stoplight race it; I don't take it to the strip. I cruise. I like that it's original. And I think a single exhaust would be cool on it just because...it's right for this car.

Thoughts?

 

[JimKueneman]

I put their dual conversion on my 318 Coronet. It sound cool, other than that for what you and I seem to care about there is no real value. The 66 Valiant I’m working on is getting the HP single they make were they make the Y more like a collector vs just a junction.

 

[Jerry Hall]

Just my opinion, but I would keep the dual exhaust. You can eliminate the drone by losing the flow masters. Stock style mufflers and dual exhaust as found on 383 & 340 cars will do the trick.

 

[diesel_lv]

A single 2" or 2-1/2" would flow just as much as a dual on a 318. Would look stock, get rid of drone and if you want a little bass, a muffler will fix that.

 

[Jeff Peterson]

Nice thing about a single, it will "dry out" quicker on short trips.

 

[JimKueneman]

To add if you drive like I do the number of times I cared if the exhaust flowed better (only a high RPM benefit) is zero. The loss of low end torque because I did not put a crossover pipe is something I would use. The single exhaust this is free

 

[440 PHIXX]

The duals look better. And the 1973-74 Road Runner with the standard 318 2bbl came with a dual system. The only 318 2bbl to do so. I think!

 

[Triplegreen500]

The single exhaust this is free

I forgot to mention that - on my motorcycles (v-twins), you get more torque out of a 2:1 setup. 2:2 give you more top-end HP, but you lose torque down low. Given the gearing (TALL) and usage (cruising), I'd think torque would be a better bet for me in this one anyway.

My '72 Satellite is the one I drive for speed and power; the Charger is a feel-good cruiser that I've wanted literally my entire life. Mom brought me home from the hospital in HER '70 500 that was also triple green (hers was F8 dark green, mine's F4 light green). My cousin wrecked hers in the mid-70s, but when I found this one...I had to have it. I don't baby it like "wipe with a diaper and never drive it"...but I don't pretend it's a performance car, either. Just a fun driver.

 

[JimKueneman]

The Accurate has the collector type Y and all. I’d go for that! Dare to be different!

 

[33 IMP]

I agree with Jerry Hall. Save money and hassle, change the mufflers. Whatever walker quiet power that fits, big as you can get (physical size, not pipe size).

 

[Triplegreen500]

It's a crappy, uneven, cobbled-together, crooked backyard Uncle Clem Special system. No reason to keep it. I could swap mufflers, and it would still be crooked, uneven, and cobbled together.

 

[33 IMP]

It's a crappy, uneven, cobbled-together, crooked backyard Uncle Clem Special system. No reason to keep it. I could swap mufflers, and it would still be crooked, uneven, and cobbled together.

........ but it wouldn't drone. If you want a whole new system, go for it! Your choice.

 

[Triplegreen500]

I guess that's my point - I do want a new system. My debate isn't "new or not", my debate is "single or dual".

 

[fine69]

I would say the “more low end torque with single exhaust” thing is but a myth. Dual exhaust is beneficial in every way from performance to the appearance of the car’s rear. The x-pipe vs. h-pipe vs. true duals is another debate.

 

[Triplegreen500]

I would say the “more low end torque with single exhaust” thing is but a myth.

Incorrect, and I have dyno sheets to prove it.

Again, on motorcycles...but it is a noticable difference. And, not brand-specific either. On a whole, a 2:1 exhaust will give significantly more low end torque than a 2:2 (with, or without, a crossover).

I have also seen (not produced on my own, however, like I have with the motorcycles) a similar result with people's diesel trucks. The Cummins comes factory with a large single; guys who switch to duals see the same results - less torque, but more top end.

 

[slepr1]

Keep it simple if performance isn't your concern. I'd keep it single, buy a complete new system and do what's needed to address the drone, if anything.

 

[diesel_lv]

Partially correct above, torque loss from duals has been proven often to be false. However, the flow of a single vs the flow of duals doesn't automatically mean better/more hp. Dual 2" has less volume than single 3". Pontiac had a true sleeper Firebird Formula in the 90's that had a single exhaust. If mandrel bent to include the y pipe, a large, for a 318, single will perform just as well as any dual.

 

[JimKueneman]

Incorrect, and I have dyno sheets to prove it.

Again, on motorcycles...but it is a noticable difference. And, not brand-specific either. On a whole, a 2:1 exhaust will give significantly more low end torque than a 2:2 (with, or without, a crossover).

I have also seen (not produced on my own, however, like I have with the motorcycles) a similar result with people's diesel trucks. The Cummins comes factory with a large single; guys who switch to duals see the same results - less torque, but more top end.

The math backs it up as well

 

[JimKueneman]

Partially correct above, torque loss from duals has been proven often to be false. However, the flow of a single vs the flow of duals doesn't automatically mean better/more hp. Dual 2" has less volume than single 3". Pontiac had a true sleeper Firebird Formula in the 90's that had a single exhaust. If mandrel bent to include the y pipe, a large, for a 318, single will perform just as well as any dual.

The problem is these comparisons are rarely the result of an exhaust that has been designed specifically for the application. If you design a dual with the crossover it will likely out perform the single across the entire band. The single is just an easy way to get the crossover in a close spot without the hassles if all you care about is low end.

 

[440 PHIXX]

In the 80’s my brother had a ‘70 Challenger with the slant 6. The muffler was all the way at the back splash pan and the tailpipe that came out of it made a 90 degree turn towards the ground. It was the silliest lookin tailpipe I’ve ever seen. It looked like a water faucet. Or a limp dick.