EPA-AA-SDSB-80-13
                          Technical Report
                       The Aftermarket Costs of
                      Heavy-Duty Diesel Mufflers
                                 by


                             Daniel Heiser


                               July 1980
                                NOTICE

Technical Reports do not necessarily represent final EPA decisions
or positions.  They  are  intended to present technical analysis  of
issues using data  which  are currently available.   The purpose  in
the  release of  such reports  is  to  facilitate  the  exchange  of
technical information and to inform the public of  technical  devel-
opments which may form the  basis  for a  final EPA decision,  position
or regulatory action.

              Standards  Development and Support Branch
                Emission Control  Technology Division
           Office of Mobile Source Air  Pollution Control
                 Office  of  Air,  Noise  and  Radiation
                U.S. Environmental Protection Agency

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Summary

     Aftermarket muffler  costs  were  determined  for the  various
classes of  heavy-duty  diesel  vehicles.    These  costs can  be  used
with other data to predict maintenance cost savings of eliminating
the  need  to replace  the  standard steel  muffler on  a  heavy-duty
diesel vehicle.  These  aftermarket  muffler costs were based  on  a
survey of muffler costs from a heavy-duty vehicle and engine parts
dealership.   The  average  muffler cost  for  each  heavy-duty diesel
vehicle class was estimated  as  follows (in  1980 dollars):

     Class IIB-IV             $136
     Class V and VI           $161
   -  Class VII                 $164
     Class VIII               $181

Introduction

     EPA  is  preparing  to propose  a  heavy-duty diesel particu-
late  emission  standard.   One possible  control  technique  is  the
trap-oxidizer.   The  addition  of a  trap-oxidizer  will require the
use  of an exhaust  system  that  will  last the lifetime of a vehicle
(i.e., a stainless  steel system).  The trap-oxidizer has also been
shown  to  reduce engine noise as well  as current mu f f lers -^/2_f
Thus,  its  use   should  eliminate  the need  for  the muffler.   This
elimination would reduce maintenance costs, since the muffler would
no  longer  need to be  replaced.   These  savings  would need  to be
taken  into  account when determining the  net  cost  per  vehicle of
adding a trap-oxidizer.  To  estimate these  savings, the aftermarket
costs  of mufflers must  be known.   Representative aftermarket
muffler costs will  thus  be estimated in  this report for the various
heavy-duty vehicle  classes.

     The method used  to estimate the  muffler  costs for heavy-duty
diesel vehicles consists of  three  major steps.   First,  actual
aftermarket  muffler  costs  for  various  heavy-duty  diesel  engines
will be obtained  from a heavy-duty  vehicle  and  engine  parts
dealership.  Second,  each  engine  (and  its muffler) will be assigned
to  a  particular vehicle  class,   based  on a  relationship  between
engine size  and gross vehicle weight.  Third,  an average'muffler
cost  will  be estimated for each vehicle class  from  the  range of
costs  available.

     The average muffler costs will be determined by  vehicle class
because this will be the most convenient form for  future use.  The
regulatory  analysis  for the heavy-duty  diesel  particulate regula-
tions  will  likely break down the costs of control by  vehicle
class.   This will  be done  because  is  it  easier  to predict future
sales  of heavy-duty diesels by vehicle class than  it  is to predict
future sales of heavy-duty diesel engines .by engine family.  Thus,
while muffler cost  data is directly  available for  individual diesel
engines, additional effort will be made to covert these costs  into
average muffler costs for  each vehicle class.  As  it  is likely  that

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the regulatory  analysis  will  group Classes  IIB,  III,  and IV  and
Classes V and VI together, respectively,  because  of the relatively
small  sales in Classes  III,  IV,  and  V, that will  be done here
also.

     All costs will be determined  in  1980 dollars.   The details of
the analysis follow.

Muffler Prices

     The  first step  in  determining  aftermarket muffler costs
for whole  classes of heavy-duty diesel vehicles  is to obtain
muffler  costs  for  individual  heavy-duty diesel engines.   To  do
this,  a survey of muffler costs  from a heavy-duty vehicle  and
engine equipment supplier, A&L Parts,  Inc. of Ann Arbor,  Michigan,
was conducted.  Most of the heavy-duty  diesel mufflers sold at  this
dealerships were produced by Riker Manufacturing.   The description
and cost  of these  mufflers  can be found  in a Riker  Manufacturing
heavy-duty  engine muffler guide,4/ and a corresponding heavy-duty
muffler resale price list.^/  The  engine-muffler  guide listed
engine models  from several  diesel  engine manufacturers with  their
corresponding  number  of  cylinders,  the  engine  displacement  (in
CID),   the  type  of  exhaust system  (single  vs.  dual),  and  the  cross
reference muffler  number.  The price list  listed the costs of  these
mufflers.

     An  examination of the price  list showed that  two  different
costs  were  given  for  each muffler.  These  costs are  known as  the
"net price" and the "list price."4/   For example,  the replacement
mufflers  for  a  Cummins model V6-155 dual  exhaust  engine  are  Riker
Manufacturing mufflers, no.  HD257  39  47 (p.  5-3),  with each of the
two mufflers  having a list  price  of $81.61,  and a "net  price" of
$54.36.J>/ (p.  5)  For  all the mufflers  contained in the price  list,
the  "list  price"  was 50  percent higher than  the  "net price."
Discussion with  the  dealer  revealed that these two costs  are
related  to  the  types  of services rendered by the dealer.   A dealer
selling  truck parts  and  providing  services  such  as   installation
often  sells these mufflers at  or near  the "list price"  while  a
dealer selling truck parts only  would sell these mufflers closer to
the "net  price."   Because no data is available on how  often heavy-
duty  diesel owners pay  each  price,  it  will be assumed  that  the
average  muffler cost  is  halfway between  the "net  price"  and  "list
price."

     Further  examination  of .the  price list also  revealed that  a
wide  range of  muffler costs exists,  from  a  $47  muffler for an
IHC-D354  diesel engine to a $306 muffler  for a Cummins V903 diesel
engine.   This wide variance  in costs  appears primarily  due  to a
wide  range of  engine sizes, the  number of  exhaust  systems  per
engine  (single  vs.  dual), and  the number of  mufflers  per exhaust
system.

Vehicle-Engine Relationship    ;

     To  categorize the  muffler costs  found above,  each muffler

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(via its engine) will be assigned to a vehicle  class.   A heavy-duty
vehicle as defined  by  EPA is a vehicle whose  gross vehicle weight
rating  (GVWR)  exceeds  8500  pounds.   The  following standard  truck
classes then fall into the heavy-duty vehicle class:

          Class                   GVWR (Pounds)
           IIB                    8,500-10,000
           III                   10,001-14,000
           IV                    14,001-16,000
           V                     16,001-19,500
           VI                    19,501-26,000
           VII                   26,001-33,000
           VIII                  33,001 and over

Vehicle Class  IIB  in  this report will always refer  to  vehicles  in
the  traditional  Class  II  category  (6,000-10,000 pounds)  with  a
weight above 8,500 pounds (i.e., those Class II  vehicles which fall
into  EPA's  heavy-duty  vehicle category).   For  purposes  of  this
analysis,  these  vehicle  classes  will  be  placed  into  four  basic
vehicle groups.  These groups are:

          Group          GVWR (Pounds)       Class

            1             8,500-16,000      IIB,II,IV
            2           '16,001-26,000        V,VI
            3            26,001-33,000        VIII
            4            33,001 and over      VIII

     The make-up of these groups  is based  on the  projected  future
of each of  the classes^/, which  is  shown  in Table 1. From Table 1
it can be seen that the relative sales of Classes III, IV,  and V are
very  small  with  respect to the other  classes.   Thus, it should be
reasonable  to  group Classes  III and  IV with Class  IIB and  to group
Class V with Class VI.

     To  facilitate  the  costing of  mufflers  for  these  vehicle
groups, each group will be  assigned  a typical engine displacement.
These engine displacements  are  350 CID (Classes  IIB, III,  and IV),
500  CID  (Class V  and VI),  640 CID (Class  VII)   and  850 CID  (Class
VIII).   These engine sizes were estimated  from  light-duty  diesel
truck and heavy-duty diesel  vehicle  and engine  data.bj   The  engine
size  estimated for a  Class IIB-IV vehicle  will  be examined  first.

     No  Class IIB-IV  diesel vehicles  are currently marketed.
However, General Motors (GM)  does  market  a light-duty diesel truck
(GVWR =  6000-8500 pounds) with a 350 CID  engine. As Class  IIB-IV
vehicles are generally  commercially-owned and operated  to  maximize
profit,  they should not require  the  acceleration capabilities of a
light-duty  diesel  truck,  which is  usually personally owned.   Thus,
an  engine  size capable of  powering  a  6,000-8,500 pound light-duty
diesel  truck  should be sufficient  for vehicles  potentially twice
that weight.

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                              Table 1




             Projected Heavy-Duty Diesel Sales by Class







          IIB    III     IV     V      VI     VII     VIII     Total
1984    14,335  2,685    456  1,114  56,338  31,678  159,555  266,161




1985    18,258  3,419    581  1,418  64,275  33,725  162,578  284,255




1986    22,316  4,179    710  1,735  72,490  35,824  165,600  302,854




1987    26,511  4,965    843  2,061  80,984  37,979  168,623  321,966




1988    30,841  5,776    981  2,398  89,755  40,187  171,645  341,583

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     To demonstrate  that  an  engine  size of  350  CID is  at  least
conceivable for a Class IIB-IV. vehicle,  it can be shown that a few
vehicles even heavier than 16,000 pounds are equipped with engines
even  smaller  than 350  CID.    For  example,  while most  Class  VIII
vehicles are equipped with engines  in the 600-900 CID range,  a CMC
JV-75 heavy-duty vehicle  (40,000-50,0000 pounds) is usually equip-
ped with a Detroit Diesel 6V-53N engine of 318 CID.6/  Thus,  a 350
CID engine  should  at least  be a reasonable  engine  size for  Class
IIB-IV heavy-duty diesel vehicles.

     Looking next  at the  other extreme,  Class  VIII vehicles,  the
average size  of 850  CID  reflects   1)  the popular  use  of Cummins
engines, nearly  all  of which are 855 CID (rounded  to  850 CID for
this  analysis)  and 2) that  about as many engines  are  larger  than
850 CID  as are  smaller  than  850  CID  for  Class  VIII  vehicles.6J

     Concerning Class VII vehicles,  a  Caterpillar  3208  engine was
known to be  popular  engine  for many of  these  vehicles.   The  Ford
87000 is one vehicle  with this engine ^6_/  The size of this engine
is 636 CID, or  rounded  to 640 CID  for  this analysis.  Again,  this
average  engine  size appears  to be in the middle of a  range  of
engine sizes that exist for  Class VII vehicles.^/  Thus, an engine
size  of  640 CID was  assigned to Class  VII.   For  Class  V  and  VI
vehicles,  insufficient  data were  available  for  estimating  an
average engine size.   Thus,  the average of the Class IIB-IV engine
size  (350 CID) and the  Class  VII engine size (640 CID) was assumed
to be a reasonable engine size for a Class V and VI vehicle.  This
comes to an engine displacement of 500 CID.

     An engine's horsepower  rating  would be another parameter for
relating  an  engine  to a  particular  heavy-duty  vehicle class
and initially,  would  appear  to be a  better one.  However, even here
no simple  correlation exists between engine  power and vehicle
class.  For example,  the  GM heavy-duty gasoline vehicles TP-31382,
CE60,  and  C550  come equipped with engines having  maximum  brake
horsepower ratings of 240, 159, and  120,  and have GVWRs of 14,500,
13,600-18,500,   and  13,800-18,000  pounds, respectively.    In other
words,  the lightest  vehicle  is equipped with the  most  powerful
engine.   In addition, a CMC CE65  vehicle(GVWR -.19,000-32,000
pounds) comes  equipped  with  a engine having  a maximum horsepower
rating of  198.j6_/  Thus,  engine  power  does not appear  to be  that
more  suitable   than  engine  displacement  for  determining a  rela-
tionship between  engines  and  vehicles.   Also, future applications
in  the sizing  and  costing of other  emission  control  hardware
components will  most  likely be done by  engine size rather than by
power, since the  size of  cost of components are primarily related
to  engine  size.  For  example, control hardware  costs for the
light-duty diesel  particulate  regulations were estimated according
to engine  size.7/  It  is  likely that, a  similar methodology will be
used  for   the  proposed heavy-duty  diesel particulate  regulation.
Thus,  it  would be  convenient  and consistent  to have  a  single
engine/vehicle  class  relationship for use in the overall analysis.

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     Engines  from the  five  largest  diesel  engine manufacturers,
Caterpillar, Cummins, Detroit Diesel,  International Harvester,  and
Mack, will be used in this analysis  as these manufacturers  comprise
about 97  percent of  the  total  heavy-duty diesel engine market ^3_/
In order  to determine  the  vehicle  group  to  which  each engine  is
associated,  the  engine  displacement  of these  engines (as  found  in.
the  Riker  Manufacturing engine-muffler guide)4/ will be matched to
the  closest engine  size  determined  for  the  four vehicle  groups.
Thus,  for purposes  of this analysis only,  a heavy-duty diesel
engine  size  of  0-425  CID will be  assigned  to Classes  IIB-IV,
an engine size of 426-570 CID will be assigned  to  Classes V and  VI,
an engine size of 571-745 CID will be assigned  to  Class  VII,  and an
engine size  of 746  CID and larger will be assigned to  Class  VIII.
While these engine  size/vehicle  class relationships are  not  ex-
clusive in  reality,  they  should serve the purposes of  this  analy-
sis.  As stated above, no Class  IIB-IV diesel  vehicles are  current-
ly marketed,  so   that  none  of  the  engine sizes between 0-425  CID
used here  currently belong  to  a Class  IIB-IV  vehicle.   However,
this analysis will  assume  that engines of  0-425 CID will have
muffler  costs that  most  closely represent  the  muffler  costs  of
future  Class  IIB-IV  diesel vehicles.   For  example,  a  Cummins.
diesel engine model  V6-155 has  an  engine size  of 378 CID  and will
be assigned  to Class IIB-IV  in  this  analysis,^/  (p. 5-3)  while at
present  this  engine  is  probably  used to  power Class  VI,  VII,  or
VIII vehicles.

Cost Per Vehicle Group

     Now that  the engine-vehicle relationship has been  determined,
the  third  step in this  analysis is  to estimate  the  average muffler
costs for  each of these four groups  of vehicle classes.   A sales-
weighted  average  should  provide a  reasonable estimated  muffler
cost  for each group.   However,  a   sales-weighted  average of  all
mufflers within  each group  can  not  be determined as sales  data on
mufflers are  not  available.  Another  method for estimating average
costs would  be to determine  the relative  sales  of each  engine sold
within  each vehicle group,  and  then examine  which  mufflers  are
associated  with  each engine, and thus indirectly develop  a  sales-
weighted  average of mufflers costs   for  each  vehicle group.   How-
ever, this  approach  also has  several  problems.   First,  some heavy-
duty diesel engines  have several applications  other than  powering
heavy-duty  vehicles.   For example,   a given  engine may be  used to
power  a  tractor  as  well  as  an over-the-road  heavy-duty  vehicle.
6/   The  breakdown of engines sold  for each type  of application is
not  available.   Second, even if the  above breakdown were kno.wn,  the
number of  engines sold  to  power each associated heavy-duty vehicle
is  not  available.   It is known,  for example, th-at a  Caterpillar
3208 or  a Ford V363 engine can be  used  in a  Ford 87000 vehicle,^/
but  it  is  not  known how many  engines of each model   are  sold to
power  this  vehicle.    Thus,  no simple  sales  relationship  exists
between  engines  and  vehicles.   Third, each  engine used  to  power
heavy-duty  vehicles  may have many  in-use applications  that affect
the  noise  output and  thus may  require several different  types of

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mufflers.   For  example, five different  types  of mufflers  can be
used on a Cummins V555 engine.4/  Estimated sales for each type of
muffler  for each engine would be  difficult  to predict.   Thus,
a single sales-weighted muffler  cost  for  each vehicle group can not
be determined due to  the lack of  sales data of either mufflers or
engines.

     Another possible method  for determining average muffler costs
would  be to  analyze  the  muffler  costs associated with  single
exhaust  and dual  exhaust systems  within  each  vehicle group separ-
ately.  This  further breakdown  should  be helpful  because muffler
costs  appear  to  be  much less for single exhaust systems than for
dual  exhaust  systems.   Also, a  projection  of  relative  sales of
vehicles' with  single and  dual exhaust systems  can be made by
assuming that turbocharged engines have  single exhaust systems and
that  naturally-aspirated engines  have dual  exhaust systems.3/
Using  this  assumption,  approximately  3/4 of all heavy-duty diesel
vehicles will  utilize a single exhaust  system.  This corresponds to
the  fraction of turbocharged  diesel  engines  sold by  the  five
largest manufacturers.^/   The remaining  1/4 of the engines (those
being  naturally-aspirated)  are  assumed  to have  dual exhaust sys-
tems.   While  a  cross-over pipe could be  used  instead  of  a dual
exhaust system on these naturally-aspirated  engines,  this  is highly
unlikely due  to  their large  engine   size.   Thus, these naturally-
aspirated engines are  assumed to require two exhaust pipes and two
mufflers.  This breakdown of  single  and  dual exhaust is assumed to
apply to each  vehicle class.

     Because  of the  lack of additional sales  data within each
exhaust system type, a single muffler cost for each  single exhaust
and dual exhaust  group of  mufflers  cannot  be determined by a true
sales-weighing.   Instead the midpoint  of  the range of muffler costs
within these groups will be used  as the  single representative
cost.  In other  words, the  estimated value  for the single exhaust
muffler  and  for the  dual  exhaust  muffler  for  each  vehicle group
will be  computed by  taking  the midpoint  of  the minimum and maximum
costs  listed  for the  two  types of  mufflers.   If a  single exhaust
system  consists  of  two mufflers in  series,  then the sum of these
two mufflers will be considered  as the  cost  of  the muffler for this
exhaust system.   The final  average cost for  each  particular vehicle
group would be  estimated  from the predicted sales  fraction of
single exhaust and dual exhaust  systems determined above.

     Looking  first  at single exhaust  mufflers  for  a Class IIB-IV
vehicle, the  least  -expensive muffler '• can be  found  on an IHC-D35-4
engine (engine size =  354 CID).   This muffler's minimum cost is $58
(halfway between net  price =  $47 and list price  =  $70).   Likewise,
the most expensive Class IIB-IV single  exhaust  muffler  can be  found
on  a  Detroit  Diesel  6V-53N  engine  (.engine  size  = 318 CID), which
costs  $182.   The  midpoint  of  the minimum and maximum cost is $120,
and  will be  assumed  to be  the sales-weighted  average  cost  of  a
Class  IIB-IV single exhaust muffler.

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     Estimating  the cost  of a dual  exhaust muffler  on a Class
IIB-IV vehicle is  done  similarly as  above.   The  least  expensive
muffler can  be found on  a  Cummins V6-155  engine  (engine size  =
378  CID),  which  has a minimum cost of  SI36.   The most  expensive
Class  IIB-IV dual  exhaust muffler costs  $235, and  can also be
found on a Detroit Diesel  6V-53N.   The midpoint  of  the minimum and
maximum  cost  is  $185,  which  is  the cost  of Class  IIB-IV  dual
exhaust mufflers.   The  costs of  the  single and dual  exhaust  muf-
flers  for  the  remaining vehicle  groups were determined  using the
same method as that  for Class  IIB-IV  mufflers and  can  be found  in
Table 2.

     The final average costs of a Class  IIB-IV  muffler is the
estimated sales-weighted average of the single exhaust  and the  dual
exhaust mufflers,  or $136  ((3/4 x $120) + (1/4 x  $185)).  Using the
same method for the remaining groups of vehicle  classes,  the costs
of mufflers on Class V  and  VI, Class  VII,  and Class VIII vehicles
are $161,  $164, and $181,  respectively.  Table 3  displays  a summary
of  costs  for  each group  of vehicle classes.   These estimated
aftermarket costs can now  be  used to estimate the effect of modify-
ing or eliminating the muffler replacement  schedule for heavy-duty
diesels.

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                                                         .   Table

                                      Costs  of Mufflers  on  Single  and Dual Exhaust  Systems


Vehicle
Class
IIB-IV



V, VI



VII



VIII
Single
Exhaust (S)
or Dual
Exhaust (D)
S

D

S

D

s -

D

. s
Engine Equipped
with Least Expen-
sive Muffler, with
Engine Size (CID)
IHC-D354 (354 CID)

Cummins V6-155
(318 CID)
Mack END-510
(510 CID)
Cummins V8-185
(504 CID)
Caterpillar 1673T,
1674TA (638 CID)
Caterpillar 1160
(636 CID)
Cummins NH230,


Minimum
Cost I/
$ 58

$136

$ 82

$146

$ 95

$146

$119
Engine Equipped
with Most Expen-
sive Muffler, with
Engine Size (CID)
Detroit Diesel
6V-53N (318 CID)
Detroit Diesel
6V-5.3N (318 CID)
Cummins V8-185,
V8-215 (504 CID)
Detroit Diesel
8V-71N (568 CID)
Caterpillar 1150
(573 CID)
Caterpillar 1160
(636 CID)
Cummins V903


Max imum
Cost I/
$182 .

$235

$213

$255

$218

$235

$202

Midpoint of
Minimum and
Maximum Cost
$120

$185

$148

$200

$156

$190

$160
                               NH250, Super 250
                               (855 CID)

                               Cummins V903
                               (903 'CID)
$235
             (903 CID)
Cummins V903
(903 CID)
                                                                                                                         o
                                                                                                                         i
$255
$245
77Halfway between "net cost" and "list cost" for each engine.

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           Table 3
Costs of Mufflers,  According
Group of
Vehicle
Classes
IIB-IV
V, VI
VII
VIII
to Groups
Average Single
Exhaust Cost
$120
$148
$156
$160
of Vehicle Classes
Average Dual
Exhaust Cost
$185
$200
$190
$245
Overall Average
Cost per Group
of Vehicle Classes
$136
$161
$164
$181

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                                  -12-
                            References

_!/   Penninga, J.,  TAEB,  EPA, "Second  Interim  Report  on Status of
     Particulate  Trap  Study,"  Memorandum  to  R.   Stahman,  Chief,
     TAEB, EPA, August 28, 1979.

27   Alson, Jeffrey,  SDSB, EPA,  "Meeting Between Texaco and EPA to
     Discuss  Particulate  Trap  Work,"  Memorandum  to  the  Record,
     October, 1979.

_3/   "Regulatory Analysis  and Environmental  Impact  of Final Emis-
     sion  Regulations  for  1984  and Later  Model  Year Heavy-Duty
     Engine," SDSB, EPA, December, 1979.

4/   "Heavy-Duty Muffler  Applications," Riker Manufacturing, Inc.,
~    No. 176A, 1976.

5f   "Heavy-Duty Mufflers  and Exhaust  System Part, Suggested List
     and Resale  Price," Riker Manufacturing  Inc.,  No. 190-4, July
     1, 1979.

6/   "Chiton's Automotive Industry," April, 1978, pp.  79-85, 94-95,
     104-107.

TJ   "Regulatory  Analysis  of  the  Light-Duty   Diesel Particulate
     Regulations  for  1982 and  Later Model Year Light-Duty Diesel
     Vehicles," SDSB, EPA, February  20,  1980.

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