[Fot] Exhaust Header

Tue Nov 5 03:04:12 MST 2013

Very interesting observations!
Maybe the numbers you found to work best are not valid for every 4 cyl TR
race engine, but it's interesting that you found that 1.5" ID of the
primaries gave the best results. Do you know wat chokes (venturi's) were
mounted in the Webers 45?
My engine dyno ,a STUSKA Trackmaster with Power Pro software, will be ready
in a month or so. I bought a Stahl header with 1.625 ID primaries. Wondering
what results I'll get when comparing my actual exhaust with 1.5"ID
primaries(I tried 34" and 40" lengths) and 2 1/4" tailpipe, with the Stahl
header. It will take some time, but I'll post the results at this place.
Marcel Van Mulders

-----Oorspronkelijk bericht-----
Van: gregmogdoc at surfnetusa.com [mailto:gregmogdoc at surfnetusa.com] 
Verzonden: dinsdag 5 november 2013 10:10
Aan: BillDentin at aol.com; van.mulders.marcel at telenet.be;
colordog.1 at earthlink.net
CC: fot at autox.team.net
Onderwerp: RE: Re: [Fot] Exhaust Header

After extensive dyno testing, we found that 4 into 1 headers with 1.5"
Inside diameter primary pipes 33 inches long going into a "merge collector"
with a "piramid" spike at the junction of the primary pipes joining into a
tailpipe 2.125" inside diameter that is 72" long to the open end is the
optimum header configuration for a full race 2200 cc TR-4 race engine with
45 mm Weber DCOE carburators. For an engine that really makes over 180 hp at
the flywheel, primary pipes 1.625" inside diameter may be benificial at
engine speeds over 5,000 rpm. We have found that a Megaphone that is 18"
long tapering from 2.125" I.D. to 2.5" I.D. boosts power and torque
throughout the entire power band, but especially just as the engine comes
"on the cam" and up the the torque peak. The megaphone takes the place of
the last 18" of the tailpipe. Shorter or longer primaries or tailpipe hurts
the power and torque. 
   We tried longer and shorter primaries and longer and shorter tailpipes.
We built 1.5" inside diameter primaries and 1.625" inside diameter primaries
adjustable in 3" increments from 26" long to 54" long and tried every one of
them. 33 INCHES IS THE CORRECT LENGTH! The same it true of the tailpipe. We
tried 2"
I.D., up to 3" I.D. in many different lengths. 2.125"
I.D. X 72" long is what works best. 

Greg Solow
The Engine Room
Sports Car Specialists
Santa Cruz, CA 95060
831 429-1800

------- Original Message -------
>From    : BillDentin at aol.com[mailto:BillDentin at aol.com]
Sent    : 10/30/2013 11:31:40 AM
To      : van.mulders.marcel at telenet.be;
colordog.1 at earthlink.net
Cc      : fot at autox.team.net
Subject : RE: Re: [Fot] Exhaust Header

 In a message dated 10/30/2013 12:26:05 PM Central Standard Time,
van.mulders.marcel at telenet.be writes:

> Steve, your headers are also a lot wider (diameter)
than mine. Bigger is 
> not
> always better and many tend to fit too wide exhaust
pipes, but maybe 38mm 
> (1
> 1/2") is definitely too small on a race car, I'll
found out before next
> racing season.
> 

Amici...

More than a few FOTers have worked on a 'tuned
exhaust'.  

I know Uncle Jack did.  And in particular, Greg at
the Engine Room.  He 
told me the exhaust pipe length can be a critical
issue too, at least with the 
headers he's developed for his Morgan applications. 
Maybe he'll chime in.

Bill Dentinger
_______________________________________________
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