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TR2/3/3A tr3 exhaust opinions needed

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twigworker

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I have never been a fan of the "stock" exhaust systems on TR3, mainly because of the issue of clearances.

Please indulge me and let me paint a picture for you.

In the present situation I am building up a complete running chassis for a customer and have run into a familiar irritant.

My customer bought a complete system from Moss, with the front muffler being a stainless Falcon unit and the rear section well made of mild steel. I add this because I want you to know that we aren't playing with ill fitting cobbled up junk.

The problem is that as the rear muffler passes under and to the left of the rear axle the two conflict.

I know that the axle is at it's lowest point as the frame is sitting on shop stands, but after the car is back together and in service it is possible that the axle will from time to time find itself resting on the bump stop rubbers just as it is at the moment.

My question is, how much louder would this beast be if I fabricated a simple pipe to replace the rear muffler/tail pipe assembly?

As a reference, on MGBs I routinely advise folks to ditch the center muffler and use only straight piping under the car while retaining the stock rear muffler. To my ear, this combination is not "too loud", depending of course on what brand of rear muffler is actually installed.

So the question again is, will the noise be nauseating? Will it be too sophomoric? What sort of tone WILL it have?

All opinions invited.

Thanks, Jack
 
The early TR2s came new with a straight pipe at the rear. When I was in college and had to watch my spending, I bought a TR2 straight pipe (I would say about 1961) because it was cheaper than buying a new rear "resonator" or "silencer" or muffler. I still have it under the patio deck. It sounded just like a TR2 and during national rallies, the roar made it hard for me to hear my navigator's "shout-outs". But the control check points could hear me coming a mile away during long quiet night rallies.

When I restored it in 1990, I installed an all stainless exhaust and found the problem you have mentioned. I have a friendly neighbour who used his oxy-acetelene unit and he heated up the pipe to put a more angled bend where it meets the rear axle and this solved the problem.

Don Elliott, Original Owner, 1958 TR3A
 
I was in the shop late today and studied on the situation a little more.

What I have decided to do is the following.

Retain the down pipe as it is.

Retain the front muffler as it is, using that oddball hanger/clamp contraption between the frame members.

Move the front muffler back about four inches and mate it to the down pipe with a site built short connector. The connector will be welded to the end of the muffler extension and inserted into the down pipe before being clamped by the aforementioned odd ball hanger.

Moving the front muffler back will allow clearance for it at the left side frame X-member element.

The OEM resonator will be returned to Moss and an another shorter unit sourced locally. Same size muffler, but about 14" long as opposed to the OEM 28" unit.

The new resonator will be positioned directly front to back of the car instead of at and angle.

It will be joined to the front muffler outlet pipe VIA a relatively short connector that will include an angle creating the transition from the diagonal front muffler to the straight on resonator. Both of the joints for that connector will be clamped instead of welded for ease of removal at a later time.

The rear hanger at the tail pipe, which will be about nine inches long, will be made up of pairs of the OEM clamp/hanger/plate as used in the OEM application. They will be hung from a hole drilled in the rear cross-member, one in front of and on on the back side of the cross-member tube. Being twins they will result in a much more reliable hanging system.

Pictures next week when I am done.;)

Jack
 
I've found with a Triumphtune branch manifold, just the one 5" x 3" x 20" straight through glasspak muffler gives a good note. Not too raucous to be uncomfortable on a long trip, nor to attract unwanted attention. The pipe through the cross must be centred top to bottom, as there is very little clearance. If not centred it will grind and rattle right beneath your backside. An engineer friend eliminated this annoying problem by neatly enlarging the oval holes each end of the cross.

Another benefit is to turn the very end of the pipe upwards at a slight angle. Then it doesn't snag on the ground when reversing out of sloping driveways. Also take the pipe out past the rear of the car so the spare wheel cover doesn't get covered in soot.

Viv.
 
I didn't make the holes oval in the square "X" brace location, I put the pipe section of the 1st muffler in my 5" vice and compressed the pipe to make the pipe oval. This way, I now had clearance top and bottom and since them - no banging, clattering or drumming of the pipe in the "X" brace holes.
 
Twigworker, some information, way back when, the British Triumph Register published a "technical bulletin" that recommended the use of the TR4 exhaust pipe support bracket below the tail end of the transmission rather than the original TR3 hanger that connected to the frame. The reason for this is that the TR4 bracket bolts to the rear transmission mount bolt and thus allows the exhaust pipe to move with the engine/transmission. This assumes also that you have rubber hanger on the back end to allow the exhaust to move there as well.
Regards,
Bob
 
Update and a comment or two...

After a discussion with the owner, I decided to change course again and go back together with the "stock" system, excepting the use of a stainless Falcon resonator in the rear. I started out this morning with a mind to do the above custom work, but I was overcome by sanity.;)

I did however make a small mod to the down-pipe as I heated and lengthened the "swelled" opening at the rear just enough to allow the front pipe of the muffler to slip in further by about 3/8". This allowed the rear of the muffler to be clear of the axle final drive even with the axle in its most down position with the rubbers against the frame. I thought about whacking 3/8" off of the pipe but just didn't. I have no clue as to whether the lack of depth of the swelled section was just a manufacturing variation or not.

Regarding the change in the front support to the TR4...Bob, I had/have a new one on the bench but decided against using it. I had a new TR3 unit in hand too and although it is more convoluted I just thought that it looked more supportive. In the end though I wasn't ecstatic about how the flat clamp cinched the two pipes together. It will work of course, but when I do this the next time I will just add a length of pipe to the end of the down pipe and make my joint aft of the center of the cruciform.

I have to ask the ether though, about the front muffler. Where is it written that the thing just has to be that long? Had they made it something close to 18" rather than the "over twenty" installing this system would have been oh so much easier to set up.

And Don, great idea! I wish that I had thought of doing that before I spent so much time getting things lined up "just so" for the clearance.

Anyway, all is well in exhaustville now. Tomorrow is another day as Scarlett said and I need to get this show on the road and ready for the body drop.

Thanks again to everyone, Jack
 
Jack,

I did a lot of experimenting on my TR-3B exhaust before coming up with what I wanted--a very nice sound. I have headers on my engine that flow into a cherrybomb muffler and end up with twin chrome outlets. The sound is music to my eras.

Paul
 
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