Exhaust note

[rjc157]

This might be a stupid Question but what affects the exhaust not in our cars I have a nos ansa exhaust and for some reason it doesn't have that healey sound

 

[HealeyRick]

Lots of variables including pipe diameter, material used in construction, thickness of material, pipe length, muffler length, etc. Probably most influential with the "free flow" mufflers is the interior muffler design: type and amount of packing material, number of baffles and placement.

 

[Bob_Spidell]

There are two basic types of mufflers: 'turbo,' and 'glasspack' (or, possibly, some combination). The 'turbo' mufflers use baffles to muffle sound, while the 'glasspacks' have a sound-absorbent material; usually fiberglass or a steel wool or similar. Your Ansas are glasspacks--I know, I've performed surgery on them--whereas the original mufflers were probably turbo types (anybody know for sure?). Usually, the turbo-type have a deeper, rumbling sound while glasspacks typically have a sharper sound (for lack of a better term). Also, Ansas have 'mini mufflers' at the tips, which probably damps some of the higher-pitched sounds. Beyond that, the type and thickness of the steel used in their construction probably has an effect. Of course, the number of holes, if any, makes a difference.

Ansas are higher-pitched than OEM, I always thought they made my BJ8 sound more like a 6-cyl Ferrari.

 

[RAC68]

Hi Ralph,

I have the same exhaust system in my lower slung BJ8P1 and every time I left my drive I would hit the resonator until the covering started to separate from the end plates. Although the leak was not obvious, it did change the exhaust note. I re-welded the end plates and retightened the connections and the exhaust note returned. I don't expect that you would have an obvious leak or you would have fixed it already. However, my indication that I did was from the type of exhaust note change you are querying about. Although the other components within the exhaust system can create a note difference, FWIW, I would examine the resonator closely.

Sorry Ralph, I misunderstood your question.

All the best,
Ray (64BJ8P1)

 

[Keoke]

Well they will not sound like an NOS one.

Basically they are Helmholtz resonators where the sound is controlled by the shape and volume of the muffler. Packing and baffles are utilized to reduce the output frequency levels.

All the other variables presented in this discussion also come in to play.

 

[roscoe]

I had a stainless steel muffler on my 100 that had no identifying marks on it so I can't say who made it but I always felt it was just over the edge of being uncomfortably loud and was most noticeable at about 60 mph and then quieted down quite a bit over that. Never having driven another Healey I figured they all sounded like that. When I crunched the muffler on a ridiculously tall parking lot hump (moving too fast before I realized how high it was, Yikes!!) it broke something inside and vibrated unbearably above about 45 mph. I pulled it off and cut it opened and all it had was a straight through baffle tube that had holes in it, nothing else. The tube had broken in half, thus the vibration. When I put on the NOS plain steel muffler I had in the barn that looks the same but is glass packed, it now sounds great and I love it. You can almost have a conversation at highway speed, but nobody would mistake me for a weeny on the road.

 

[Patrick67BJ8]

I had to drill all the holes in my frame for mounting the exhaust system and I was able to gain a little more clearance by assembling the whole system and raising it into position using a couple of 2"x12'x12" boards and a jack under each board. I then marked the best position for the exhaust hangars and then lowered the system and drilled the holes. My system hangs close and centered to all the underside. It was worth the extra time.

 

[Bob Claffie]

Back in the day I had a 1959 100/6 slash 3000. I sawed the stock muffler lengthwise on an aborted attempt to isolate the halves of the exhaust to make the exhaust note "sharper". Original muffler consisted of two louvered straight pipes surrounded by fibreglass. (Experiment failed). Bob

 

[HealeyRick]

Back in the day I had a 1959 100/6 slash 3000. I sawed the stock muffler lengthwise on an aborted attempt to isolate the halves of the exhaust to make the exhaust note "sharper". Original muffler consisted of two louvered straight pipes surrounded by fibreglass. (Experiment failed). Bob

Wonder how it would have sounded with a separate muffler for each pipe? The six cylinder Healey was already a bit different by having a split manifold with two exhaust pipes which was a hot set-up for early 50s I6 American hot rods. But the American hot rods ran two glasspacks to the rear. Healey ran the two pipes back from the manifolds, but then combined them back into one muffler with dual inlets and outlets. Be interesting to hear one with true duals.

 

[Bob Claffie]

Yes Rick, my intent was to mimic the 6 cylinder Corvette. I had a girlfriend who had a '54 Vet whose previous owner installed glasspacs in place of the stock mufflers. The "rap" in those pipes was incredible as the exhaust note started out quite loud and then tapered off somewhat and came back around 4000 rpm with a vengeance. The Healey muffler with a sheet steel divider separating the two sides made no difference whatsoever ! I never checked but I'll bet the firing order was different between the Chevy and the Healey.

 

[Keoke]

Wonder how it would have sounded with a separate muffler for each pipe?

I do not know Rick but those mufflers also acted like a balance pipe.

 

[Patrick67BJ8]

Wonder how it would have sounded with a separate muffler for each pipe? The six cylinder Healey was already a bit different by having a split manifold with two exhaust pipes which was a hot set-up for early 50s I6 American hot rods. But the American hot rods ran two glasspacks to the rear. Healey ran the two pipes back from the manifolds, but then combined them back into one muffler with dual inlets and outlets. Be interesting to hear one with true duals.

Maybe even better with a crossover pipe to connect the two exhausts on BJ8's?

 

[steveg]

Maybe even better with a crossover pipe to connect the two exhausts on BJ8's?

The problem there is a crossover pipe would make the BJ8 even quieter. IMO BJ8s are already too quiet.

 

[Keoke]

Healey ran the two pipes back from the manifolds, but then combined them back into one muffler with dual inlets and outlets.

Here again-Patrick
This setup eliminates the need for a balance/crossover pipe which can complicate exhaust system servicing.

Late BJ8 cars use separate mufflers but met German noise acceptance levels without Crossover pipes.-

OH!! Daimler V8 saloons got crossover pipes-:wink-new:

 

[RAC68]

My ANSA exhaust system has separate free-flow mufflers and piping but comes together in the resonator. The shared resonator has 2 inlets and 2 outlets so I don't know if it functions, or could function (given the distance from the engine), to balance the exhaust.

Ray (64BJ8P1)

 

[Keoke]

My ANSA exhaust system has separate free-flow mufflers and piping but comes together in the resonator. The shared resonator has 2 inlets and 2 outlets so I don't know if it functions, or could function (given the distance from the engine), to balance the exhaust.

Ray (64BJ8P1)

Well Ray:

If we accept the concept that the balance pipe equalizes back pressure in the system your resonator may qualify.

However, I have no experience with that aftermarket exhaust system .

 

[Patrick67BJ8]

Well Ray:

If we accept the concept that the balance pipe equalizes back pressure in the system your resonator may qualify.

However, I have no experience with that aftermarket exhaust system .

I believe it was Smoky Yunik who came up with the idea of a crossover pipe to increase hp in his stockcar.

 

[Patrick67BJ8]

The problem there is a crossover pipe would make the BJ8 even quieter. IMO BJ8s are already too quiet.

My Bell stainless system has a nice mellow note. As more carbon stuff get's into the muffler it will no longer have any of the stainless sound(I'm told}.

 

[gonzo]

My BJ7 is equipped with true dual exhaust - two separate 4 in. glass packs on 1 3/4 in. piped straight to the back. System sounds great - albeit a little loud at highway speeds. As an expensive "experiment", a SS exhaust system was installed and tested for two months, but the sound was reedy / tinny and performance dropped noticeable compared to the true dual exhaust.

Digging the pop and fizzle of a 6 cylinder engine on dual / straight-through exhaust - loud and proud!

SS system is now garage wall-art. Down pipes are beauties! Gonzo.

 

[vette]

If the original muffler has a perforated/ventilated central bulkhead which allows the two sides to co-mingle then that will act as a cross over pipe. this will smooth out the pulses and also lower the decibels alittle. I built a new engine for my '70 Vette last winter and did alot of home work along the way. One of the books I read claimed that a crossover pipe will smooth things out considerably but doesn't necessarily contribute to more horsepower. This was the ultimate conclusion of alot of dyno testing. I have been running 2.5" straight chambered pipes down the center of my '70 Vette for about 5 years without a cross over pipe. It sounds mean under 2500 rpms but at highway speeds the resonance is ah, what should we say, very vibrant. You can bet when I put it back on the road later this year it will have a crossover pipe. Dave.