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TR4/4A TR4a exhaust manifold on a TR4?

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doughairfield

doughairfield

Jedi Trainee
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Is it possible to fit a TR4a exhaust manifold onto a TR4 AND run the dual exhaust?

I was under the TR4 the other day and was trying to figure out how I would run the 2 exhaust pipes through to the back and cant see how. The current single exhaust pipe runs the middle of the frame, but there isn't room for a second pipe to come through.

Additionally, I was thinking of putting the later, longer type intake manifold on my TR4 when/if I swap the exhaust manifold out. Would these 2 things in conjunction likely provide a performance gain? Any downsides?
 
The stock dual exhaust has a single pipe from the front muffler to the back and then splits in two. Can't help with details of swaping parts.
 
Lake Pipes!

I have enough trouble hanging & tweaking & clamping & welding to keep that simple one pipe from banging against anything -- can't imagine having to deal with a more complex system with the TR4 ladder frame.
 
The 4A manifold + double downpipe + y pipe to single pipe is a bolt in swap. I have it. I would be concerned about fitting 2 pipes in there, it would indeed be tight.
 
On my previous TR4 (1964)I added what you described. To a "long" 4 intake I added a TR4A exhaust manifold. The 4A exhaust is a 4 into 2 manifold with a Y pipe making a 2 into 1 at that juncture. I, at that point, continued it as one pipe to the rear. It essentially was a bolt on operation. I also had HS 6 carbs.
The car ran very well with no other mods. My TR6 friends are still scratching their heads regarding its power.
Bob
 
Thanks Bob,
My TR4 is also a 64. Did you notice any power gains with the addition of the TR4a exhaust?
 
Didn't the 4A put out 104 BHP vs. 100 for the 4 and torque went up about 4 ft lbs as well. I believe the onl difference was the intake manifold and the exhaust. I had a 4A with an 87mm big bore high compression kit. Tha engine pulled really well.

Edit: Apparently the 4A had a revised camshaft
 
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