Mandrel Myths

These are some of the myths that you will hear from our competitors.
Ask about our $5000.00 mandrel power guarantee.

Bob's Muffler Mandrel Bent Power Systems

1. Myth-We have dyno results that will show pressure bending will
give you more power than mandrel bending.

Truth-Some of our competitors are getting desperate.  Since they
don't have a mandrel bender, they will do or say anything to convince
you that you do not need mandrel bending.  We have dyno results
from several local businesses with a Nascar dynamometer that will
show the benefits of mandrel bending over press bending.  Any
dyno has a 6% margin of error, so unless you dyno a vehicle under
a controlled environment, you will not get accurate results.  You
can also call Flowmaster at 800 544-4761 or Magnaflow at 800
221-2298 to get more information on mandrel bending vs press

Consider a straight plastic straw that you might use to drink a soft drink.
If the straw is completely straight, it's very easy to blow air through the
straw, as there are no restrictions. However, lets say you decide to
bend the straw 90 degrees into an "L" shape. Now, blowing air through
the straw will be very difficult, as the opening at the straw's elbow will have
changed from a circle to a very narrow slit. This is exactly how the pipes

Press Bent

Mandrel Bent

in your car's intake and exhaust system work. Air is drawn through pipes,
which, when "compression bent," become very restrictive to the flow of
air. Mandrel bending is the solution to this problem. Mandrel bending
works much like the flexible straws that you can buy in a grocery store.
When the straw is bent, a flexible section of the straw expands to maintain
the round opening no matter how much of an angle the straw is bent at.
When an exhaust or downpipe is manufactured with mandrel bends, the
steel is allowed to stretch on the outside of the bend and compress on the
inside of the bend, maintaining the nominal pipe diameter.  Exhaust gas
follows fluid dynamics.  You want to eliminate backpressure while
maintaining exhaust gas velocity.  Mandrel bending allows the hot exhaust
gases to flow with less turbulence.

Remember, all of your muffler & exhaust manufactures, all of your
car & truck magazines that do there own independent tests, and
all of the independent test that you see on the internet all show the
advantages of mandrel bending over press bending.  Even your new
car manufactures are aware of the benefits of mandrel bending, and
are offering mandrel bent pipes direct from the factory.  If you want
to save some money, and you don't need the extra power, we can
offer you a press bent system for less.  A Bob's Muffler, mandrel
bent system, will give you the most power possible. 

Click here for local dyno results

2. Myth-You don't need mandrel bending unless you have a nascar running
800+ horsepower.

Truth-Mandrel bending alone will add 3-5% more horsepower and torque.

3. Myth-Your motor is to small for mandrel bending to make any difference.

Truth-It doesn't matter what size your motor is you will still get a
3-5% gain in horsepower & torque.  Obviously the bigger the motor, and
the more horsepower you have, the larger the gains.

4. Myth-We will only be making a few small bends so you don't need
mandrel bending.

Truth-(We will be using 3" tubing as our example)  It doesn't matter if
you bend a pipe 1 degree or 180 degrees you will still smash the pipe
1/2 inch.  A press bender will crush the pipe before it starts bending.

5. Myth-We will only be putting 1 bend in the pipe so you don't need
mandrel bending.

Truth-If you have 3" tubing that is press bent it will smash 1/2 inch at
the center of the bend.  At that point you have 21/2" flow instead of
3".  It doesn't matter if you have one bend or five bends you still have
21/2" flow.

6. Myth-My vehicle has press bending and it runs just fine.

Truth-This statement is my favorite.  Since the muffler shop owner
doesn't have a mandrel bender, and has a press bent system on his
vehicle, he assumes that you will believe a smashed pipe will flow
better than a pipe that isn't smashed.  Mandrel bending will give you
the most power possible.

7. Myth-You don't need a custom bent system for your diesel, we
can order a kit that has been engineered for your diesel truck to give
you more power.

Truth-We are the only muffler shop in the United States that can
mandrel bend your diesel system.  Our competition has no choice
but to sell you an expensive kit.  Here is one example why our
systems are superior.  If you have a catalytic converter on your
truck you will have either a 3" or 31/2" connection on the inlet
and outlet of the converter.  Those pre bent kits are designed
to bolt on to your existing converter.  That means that your 4"
system will have only 3" or 31/2" flow instead of 4".  Bob's
Muffler will custom fabricate your converter and your system
so it will have a 4" inlet and outlet.  Bob's Muffler will give you
a true 4" system from start to finish to give you the most
power possible.

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