[6pack] exhausting question

[glemon at neb.rr.com]

A few years ago someone on the British Car Forum said they were going to do some comparison tests, stock manifold vs. header on a TR6 motor.

I know on my TR250 I went with the later dual outlet manifold, if you did the math, I did but didn't keep it, the dual manifold has significantly larger overall pipe diameter so theoretically should be better or at least higher flow for that reason. I also know there is a lot more to exhaust and header efficiency than pipe diameter.

The old Kastner books say they could never get as much power out of a dual pipe exhaust system  as a single big pipe, but that is presumably peak high rpm racing power. Don't know how much difference there is at the low end.

FWIW, my TR250 did an electronically timed 1/4 mile at a consistent 16.7 seconds at a club event a few years ago. Driving hard but not murdering the clutch or tires.  Road and Track got 17.8.

Slightly modified, but still very docile street motor, mild cam, 9.5/1 compression with shaved head, lightened flywheel, TR4A Strombergs Carbs, Late TR6 manifold,  dual pipe custom exhaust by local shop (very quiet, actually a little too quiet).

So if you wondered what some mild mods to the motor get you there you go, appreciable gain, but still slower than a soccer mom in hurry in a modern SUV.

Greg Lemon
TR250

---- Robert Lang via 6pack <6pack at autox.team.net> wrote: 
> Hi,
> For the header - get the Goodparts header. Awesome quality and a BOLT IN. For the rest of the system, I recommend custom, mandrel bent with a "turbo" muffler, but you can make any of the off-the shelf SS systems fit with the Goodparts header.
> Regards,Bob LangTR6s
>  
> 
>     On Thursday, December 14, 2017 9:59 AM, Rochlin Robert via 6pack <6pack at autox.team.net> wrote:
>  
> 
>  I put a Bell stainless system on my ’72 TR6 after a major rebuild about 3 years ago. The system I chose was the kind of stock looking system, but it has preformed wonderfully and sounds good without being too loud.  The fit of the bell system is exceptional. Best wishes for a happy holiday season to all. Bob Rochlin
> 
> 
> On Dec 13, 2017, at 2:22 PM, John North via 6pack <6pack at autox.team.net> wrote:
> I have had the Ansa in my 76 TR6 for around 15 years.   I do like the look of the two twin tips at the rear.   I can't say anything about supposed hp benefits, since I have no pre-post data, but I am well satisfied with it.   It is rather loud,  and it is fun to take off from a light and accelerate through the gears.   I added overdrive and that helped a lot with high speed runs.
> 
> John North
> On Wed, Dec 13, 2017 at 11:04 AM, Yahoo via 6pack <6pack at autox.team.net> wrote:
> 
> After 20 years, I need to replace the custom exhaust and the header that came on my 73 in 1997.   Looking at Ansa,  but wanted to get folk's opinions and recommendations.    On the header, I'm wondering if I should simply go back to an exhaust manifold that's correct for my year,   I hear that the later exhaust manifold actually flows okay.      This is strictly a street car that typically doesn't see high revs.    If I stick with header, the choice seems to be Pacesetter or one of the SS ones from England.   Head shaved to give about 9.3 compression.   Early TR6 PI type camshaft.   Crane ignition, SU carbs. KN filters
> The general tone of on-line comments on monza exhausts for TR6 isn't enthusiastic.
> I was advised that getting a pre-built exhaust may be way to go for TR6 as needed bends are trickier for a local exhaust shop.
> cheers & thanks,   Bruce Simms
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