Classic Mustangs List Archive

This read-only message was archived from a public mail list.
Mail From: David J Harr (email redacted)

<Various good points about PS brackets and stuff deleted>

I forgot to mention:

Manual Transmission (4-speed)
Manual Steering
I have the HiPo clutch equalization bar already, not a problem

Looking back over some back issues of Mustang Monthly, I noticed
that they did an article on the Dr. Gas synchronizing crossover
exhaust on a 5.0 car. I called the guys up at Dr. Gas, and they
say they have a specific application for the tri-ys and a '66 V8
I am really tempted to go ahead and order the thing, and see how
it works on the car. Anyone have any experience with this?


David

'66 Mustang GT
'86 VFR750F
'93 NC30


David J Harr
MPEG twiddlemeister
Daikin Comtec Laboratories
(email redacted)

Why is this .sig black?

**********************************
* *
* Seymour Cray 1925-1996 RIP *
* *
**********************************

This read-only message was archived from a public mail list.
Mail From: Max Watson (email redacted)

Dave, this Dr. Gas synchronizing crossover - is it to eliminate the
1800-2200 RPM drone?

--
Max Watson
<(email redacted)> Tractor Factor Productions
Santa Rosa, CA sonic.net/~max

This read-only message was archived from a public mail list.
Mail From: David J Harr (email redacted)

<This originally appeared on the classic-mustangs list. I believe
my reply is of enough general interest that I am also forwarding
it to fordnatics. If I overstep the boundaries of good taste by
crossposting - mea culpa...>

>Dave, this Dr. Gas synchronizing crossover - is it to eliminate the
>1800-2200 RPM drone?
>
>--
>Max Watson
><(email redacted)> Tractor Factor Productions
>Santa Rosa, CA sonic.net/~max

There was an article in the June or July version of Mustangs Monthly
that talks about these in the context of a late model 5.0L install.


To quote from the article:

"[The sound of a Dr. Gas crossover being heard in Winston Cup races
this year] is reminiscent of the Ford GT-40 and the vintage Formula
1 V-8 Cosworth - a unique sound developed with a 180-degree exhaust
system.

"Why was the 180-degree exhaust system necessary anyway? The reason
engine tuners used 180-degree exhaust systems was to eliminate firing
order pressure differences between the right and left cylinder banks.
[A] V8 four-cycle engine, during a power cycle, [will have] two
cylinders on the same bank fire within the same 90 degrees of
crankshaft rotation."


The author goes on to explain that this creates an imbalance between
the two banks, and, under certain circumstances, it creates a "reversion
effect" wherein an exhaust pressure wave is reflected back into the
manifold and collides with the exhaust gases coming from the next
exhaust stroke. A balance tube will help in low and mid-RPM conditions
to reduce this effect, but it will not work at high RPMs. Other designs
which work at high RPMs fail to resynchronize the pulse and pressure
spikes in an engine system. Supposedly, the "synchronizing crossover"
that is employed in the Dr. Gas system "evenly splits, smoothes [sic],
and synchronizes exhaust pressure waves at all engine speeds...
Additionally, secondary scavenging will continue to take place."

The whole thing is about $160.00, so I figured "What the heck, I'll
try it." We'll see if it works as claimed...


David



David J Harr
Troublemaker at Large
(email redacted)

Why is this .sig black?

**********************************
* *
* Seymour Cray 1925-1996 RIP *
* *
**********************************