[DeTomaso] Magnaflow Exhaust for Pantera

[Daniel C Jones]

> Matt Rodrez Rodriguez <https://www.facebook.com/mattrodrez.rodriguez>

I'm not on Facebook but if someone wants to contact him and get his email
address (or send him mine), I'd like to talk to him.  We've dyno tested the
Magnaflow mufflers against the OEM and Euro ANSA mufflers on several
Pantera engines and have a header design.

> Yes, that's pretty crude.  The headers are actually very effective,
surprisingly so considering their small collector (as verified by Dan Jones
dyno testing).

I think you are recalling a different test.  I did not test the Hall
Pantera headers.  I've tested the Euro GTS headers (2" primaries and 2 1/4"
collectors) which have a very short tri-y collector.  Compared to Mustang
long tube headers (1 3/4" primaries and 3" collectors), they performed
pretty well on peak power but did give up a good bit of peak torque.
Though I did not test them, I have a set of the Hall headers here.  They
were advertised in Hall's catalog as having 1 7/8" primaries but I measured
the primaries at 1 3/4" OD.  The primaries look decent enough with fairly
equal lengths and large radius bends but the collectors are only 1 7/8"
ID.  With a non-flat plane crank 90 degree V8, you have a pair of adjacent
firing cylinders that arrive at the collector in close proximity and have
to fight for space and the collectors on the Hall headers are too small.
If you cut the collector off the Hall headers and replaced with one with a
2 1/2" ID, they'd be decent enough.

I've got a couple of ideas about under car headers for the Pantera.  I
think it is possible to gain back the lost peak torque from the typical
shorty 4-into-1 headers by doing a tri-y long tube design.  The key with
the tri-y is that two small diameter pipes can be routed past the
halfshafts where four tubes could not.  The tri-y would have a pair of
merges before the half shaft and one merge aft (on each side).  I've got
the parts to test the tri-y design on the dyno as soon as its convenient.

http://s1127.photobucket.com/user/danielcjones2/media/351%20Cleveland%20Stuff/high_port_ss_tri_y_02.jpg.html

I also think the typical 4-into-1 design could be improved by adding
anti-reversion chambers in the primaries like the Japanese tuner cars use.
You'd want to pair those with a cross-over and a cam with a narrow lobe
separation angle.  You can see the chambers in the lower left picture here:

http://www.hytechexhaust.com/products_bdc_series.html

With their canted valves, Cleveland cylinder heads are more susceptible to
exhaust reversion than inline valve heads so the anti-reversionary chambers
(or header flange with AR cones) would be a good idea.

> Which brings us back to this Magnaflow system.  Has anybody ever seen
Foose's car in person and heard it run?

I wonder if they simply shortened the mufflers like Kirk did to my
Magnaflows?  Initially, I was going to mount them like Sean did his.
However, I noticed they might fit better if a corner was knocked off to
clear the diagonal unibody reinforcement under the car.  Kirk took a look
and decided to take the mufflers back to his shop to see what he could do
with them.  He mocked them up and instead of knocking the corner off, he
opened up the entry end and shortened them.  The mufflers are single inlet
with dual outlet and have a section of straight pipe internal to the
muffler before they split.  Kirk shortened the straight inlet pipe portion
and welded the shortened case back together.   You can slip on any sort
angled tip you like over the existing outlets.

Before cutting into the mufflers, I called Magnaflow to see if they could
make a shorter muffler and they said they don't do custom mufflers but it
sounds like they would be willing to do a group buy on modified mufflers.
The question is are they doing just the mufflers and pipes to a particular
header collector or a complete system with headers.

Dan Jones
-------------- next part --------------
   > Matt Rodrez Rodriguez
   <[1]https://www.facebook.com/mattrodrez.rodriguez>
   I'm not on Facebook but if someone wants to contact him and get his
   email address (or send him mine), I'd like to talk to him.A  We've dyno
   tested the Magnaflow mufflers against the OEM and Euro ANSA mufflers on
   several Pantera engines and have a header design.
   > Yes, that's pretty crude.A  The headers are actually very effective,
   surprisingly so considering their small collector (as verified by Dan
   Jones dyno testing).
   I think you are recalling a different test.A  I did not test the Hall
   Pantera headers.A  I've tested the Euro GTS headers (2" primaries and 2
   1/4" collectors) which have a very short tri-y collector.A  Compared to
   Mustang long tube headers (1 3/4" primaries and 3" collectors), they
   performed pretty well on peak power but did give up a good bit of peak
   torque.A  Though I did not test them, I have a set of the Hall headers
   here.A  They were advertised in Hall's catalog as having 1 7/8"
   primaries but I measured the primaries at 1 3/4" OD.A  The primaries
   look decent enough with fairly equal lengths and large radius bends but
   the collectors are only 1 7/8" ID.A  With a non-flat plane crank 90
   degree V8, you have a pair of adjacent firing cylinders that arrive at
   the collector in close proximity and have to fight for space and the
   collectors on the Hall headers are too small.A  If you cut the
   collector off the Hall headers and replaced with one with a 2 1/2" ID,
   they'd be decent enough.
   I've got a couple of ideas about under car headers for the Pantera.A  I
   think it is possible to gain back the lost peak torque from the typical
   shorty 4-into-1 headers by doing a tri-y long tube design.A  The key
   with the tri-y is that two small diameter pipes can be routed past the
   halfshafts where four tubes could not.A  The tri-y would have a pair of
   merges before the half shaft and one merge aft (on each side).A  I've
   got the parts to test the tri-y design on the dyno as soon as its
   convenient.
   [2]http://s1127.photobucket.com/user/danielcjones2/media/351%20Clevelan
   d%20Stuff/high_port_ss_tri_y_02.jpg.html
   I also think the typical 4-into-1 design could be improved by adding
   anti-reversion chambers in the primaries like the Japanese tuner cars
   use.A  You'd want to pair those with a cross-over and a cam with a
   narrow lobe separation angle.A  You can see the chambers in the lower
   left picture here:
   [3]http://www.hytechexhaust.com/products_bdc_series.html
   With their canted valves, Cleveland cylinder heads are more susceptible
   to exhaust reversion than inline valve heads so the anti-reversionary
   chambers (or header flange with AR cones) would be a good idea.
   > Which brings us back to this Magnaflow system.A  Has anybody ever
   seen Foose's car in person and heard it run?
   I wonder if they simply shortened the mufflers like Kirk did to my
   Magnaflows?A  Initially, I was going to mount them like Sean did his.A
   However, I noticed they might fit better if a corner was knocked off to
   clear the diagonal unibody reinforcement under the car.A  Kirk took a
   look and decided to take the mufflers back to his shop to see what he
   could do with them.A  He mocked them up and instead of knocking the
   corner off, he opened up the entry end and shortened them.A  The
   mufflers are single inlet with dual outlet and have a section of
   straight pipe internal to the muffler before they split.A  Kirk
   shortened the straight inlet pipe portion and welded the shortened case
   back together.A A  You can slip on any sort angled tip you like over
   the existing outlets.
   Before cutting into the mufflers, I called Magnaflow to see if they
   could make a shorter muffler and they said they don't do custom
   mufflers but it sounds like they would be willing to do a group buy on
   modified mufflers.A  The question is are they doing just the mufflers
   and pipes to a particular header collector or a complete system with
   headers.A
   Dan Jones

References

   1. https://www.facebook.com/mattrodrez.rodriguez
   2. http://s1127.photobucket.com/user/danielcjones2/media/351%20Cleveland%20Stuff/high_port_ss_tri_y_02.jpg.html
   3. http://www.hytechexhaust.com/products_bdc_series.html