View Full Version : TR4/4A TR4A exhaust: Twin or crossbox?

04-01-2006, 04:44 AM
Hi, new member first post.

I have a TR4A with non-stock exhaust that needs replacement. I've got the original 4 into 2 TR4A cast manifold. I would like to use one of the two stock exhausts for this car, in stainless steel. The TR4A had two different exhaust systems in its producion life: The "twin" system that has two mufflers at the rear and a third muffler up front near the gearbox. This system was later replaced by the "crossbox" design which continued in slightly modified on the TR250 & TR6 until end of production. This later system consists of one large transvere ("crossbox") muffler at the rear. I have been told that this later system is superior to the earlier "twin" and sounds better to boot.

My question to the list: Should I go stainless Twin or stainless crossbox? Both cost the same. Any anecotal experiences appreciated.


04-01-2006, 06:36 AM
I have a '62 TR4 that has a header going to the stock stainless steel TR4A dual exhaust without the third muffler up front and the sound is great, not too loud. Good luck.

04-01-2006, 09:02 AM
I doubt there is much, if any, performance gained from either setup on a stock engine. My setup is same as Jim's: tubular header with y-pipe into twin stainless rear mufflers, no front muffler. I haven't heard it yet though but it fits nicely.

04-02-2006, 04:45 AM
Thanks for the info. After studying the diagrams in the Moss catalog, I see that indeed the later Y-piece could substitute for the forward muffler of the earlier system, thus leaving just the two mufflers at the rear. Neat! The only problem is that the Falcon kits come as complete kits, I don't think one can mix & match parts.

04-02-2006, 10:40 AM
Bought my Falcon piece meal from TRF.

04-02-2006, 05:52 PM
Yeah, you can get individual pieces of Falcon (and other) exhaust systems from most of the vendors, definintely from TRF. Just talk to them about it. (John Swauger at TRF Level II support would be a good person to start with, either by phone or email.)

You might need to have something fabricated at the front. This is a good opportunity to add a flex joint there, if you wish. A local muffler shop can likely make up something for you.

I know someone who has a twin muffler exhaust installed on TR4/4A and it definitely sounds sweet! If I recall, it's a TR250 mild steel exhaust mated up to a TR4/4A exh. manifold. Doing the same with stainless would be pricier, so depends on your budget, I suppose.

I haven't studied the systems you mention, but personally I'd like to see some sort of crossover, so that the exhaust pressure can balance. I don't know if my friend's car has that or not, so really don't know how that would effect the exhaust note. I do think a crossover would give the best performance. A TR250 system, since it's for a 2.5L engine, is likely just a little larger than TR4/4A 2.1L system, so probably is a little more free-flowing.

I've got the Falcon 4-2-1 s/s header feeding into the Falcon single pipe, single muffler s/s "sport" exhaust system on my TR4. It's pretty well made and was a good fit. (My only complaint, wish they'd used better, mandrel bends in a few places in the exh. pipes... the header bends are great.) Am looking forward to some day actually hearing how it all sounds and finding out if the exhaust is louder than the Webers sucking in air and fuel!


04-02-2006, 07:44 PM
I have the Falcon "Sport" stainless duals on my TR6 along with the Falcon two-piece stainless headers. The problem with Falcon (or any other large bore, large muffler system) is they are so large, especially the double rear mufflers, that they are virtually impossible to "hang" like all mufflers should be. This, of course, is for the exhaust to expand and for the engine to shake, and not break your exhaust manifold. What I did was fabricate two additional cross braces in the rear of the car frame, one at the rear and one in front of the differential. I rigidly bolted the exhaust and mufflers to these braces and installed stainless 12" flex couples around the middle of the system. I also fabricated a steel shelf behind the tranny hanging down (basically a large U bracket) that the system rests on for support but without any bolting. I cushioned the pipes on this U bracket with fire-proof shielding fabric that rests under the tail pipes and atop the bracket. Confused yet. The flex joints I had custom made by epiflex.com to fit perfectly over the Falcon pipes. (I just cut out a section of the Falcon pipes and slid in the flex pipes. Instead of U-bolt clamps, which crimp and distort your pipes, I used wide stainless band clamps from Stainless Specialties in Florida (on the web). I can now take down my system without any problem, the band clamps hold securely but don't distort. My engine shakes aplenty but the flex pipes absorb it all. Works well for me.


04-03-2006, 12:02 PM
just to throw a wrench into the works, the competition systems for the 2138 all use a single exhaust pipe system with headers. the agreed upon size is 2 1/4" exhaust after the header.