Exhibit 3
 
 BASIS OF PRESENTATION
  www.sedar.com www.sec.gov.
 FORWARD LOOKING STATEMENTS




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BUSINESS OVERVIEW
    2




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CWI
   Westport HD  LNG Systems for Heavy-Duty Trucks
   3




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Juniper
  Weichai Westport Inc. (WWI)
   4




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Corporate Development and Technology Activities
   External market conditions
    5




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SELECTED ANNUAL FINANCIAL INFORMATION
 Selected Statements of Operations Data for Fiscal Years Ended March 31, 2007 to 2009
 Fiscal years ended March 312009
    
    
    2008
    
    
    2007(expressed in thousands of Canadian dollars, except for per share
amounts, shares outstanding and units shipped)Units shipped
    
    
    4,038
    
    
    
    2,720
    
    
    
    2,001Total revenue
    
    
    121,837
    
    
    
    71,536
    
    
    
    60,480Gross margin
    
    
    30,817
    
    
    
    22,513
    
    
    
    22,099GM %
    
    
    25
    %
    
    
    31
    %
    
    
    37
    %Net loss
    
    
    (24,425
    )
    
    
    (10,315
    )
    
    
    (11,307
    )Net loss per share  basic and diluted (1)
    
    
    (0.81
    )
    
    
    (0.41
    )
    
    
    (0.53
    )Weighted average shares outstanding
    
    
    30,268,947
    
    
    
    25,167,966
    
    
    
    21,478,521Cash and short-term investments
    
    
    82,619
    
    
    
    22,762
    
    
    
    23,081Total assets
    
    
    135,504
    
    
    
    78,940
    
    
    
    59,633Long-term financial liabilities (2)
    
    
    28,543
    
    
    
    5,762
    
    
    
    22,648Cash used in operations before changes in non-cash
working capital
    
    
    (25,625
    )
    
    
    (17,594
    )
    
    
    (11,325
    )CWI income for the year after taxes
    
    
    7,832
    
    
    
    11,632
    
    
    
    12,114JV Partners share of CWI income
    
    
    3,916
    
    
    
    5,816
    
    
    
    6,057
 (1)
    
    Fully diluted loss per share is not materially different as the effect of conversion
of stock options, warrants and performance share units would
be anti-dilutive.(2)
    
    Excluding current portions of warranty liability and long-term debt obligations, and
Joint Venture Partners share of net assets of joint ventures OVERVIEW OF FISCAL 2009 RESULTS
 Operating Results
   6




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Capital Management
   7




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Cash & Investments
    8




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Critical Accounting Policies and Estimates
  Variable Interest Entity Accounting
  Warranty Liability
   9




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Revenue Recognition
  Inventories
  Long-term Investments
  Equipment, Furniture, and Leasehold Improvements and Intellectual Property
   10




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Stock-based Compensation
  Adoption of new accounting standards
 General Standards of Financial Statement Capital
Disclosures Inventory Goodwill and Other Intangible Assets Financial Instruments  Disclosures Financial Instruments  Presentation
 Financial Statement Presentation:
  Capital disclosures:
   11




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Inventory:
  Financial Instruments:
  NEW ACCOUNTING PRONOUNCEMENTS AND DEVELOPMENTS
  Goodwill and Intangible Assets:
 Goodwill and Other Intangible Assets Research
and Development Costs
 International Financial Reporting Standards:
   12




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DISCLOSURE CONTROLS AND PROCEDURES AND INTERNAL CONTROL OVER FINANCIAL REPORTING
   13




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FINANCIAL OVERVIEW
 RESULTS FROM OPERATIONS
 Revenue
 (expressed in thousands of Canadian dollars except for units)
 Fiscal years ended March 312009
    
    
    2008
    
    
    2007Engine shipments (units)
    
    
    3,907
    
    
    
    2,684
    
    
    
    1,993HPDI Fuel Systems (units)
    
    
    131
    
    
    
    36
    
    
    
    8Total Unit shipments
    
    
    4,038
    
    
    
    2,720
    
    
    
    2,001Product revenue
    
    
    102,755
    
    
    
    55,238
    
    
    
    47,195Parts revenue
    
    
    19,082
    
    
    
    16,298
    
    
    
    13,285121,837
    
    
    
    71,536
    
    
    
    60,480
 Product Revenue by Geographic Region
 (as a percentage of revenue)
 Fiscal years ended March 312009
    
    
    2008
    
    
    2007Americas
    
    
    84
    %
    
    
    66
    %
    
    
    72
    %Asia
    
    
    4
    %
    
    
    18
    %
    
    
    13
    %Rest of the world
    
    
    12
    %
    
    
    16
    %
    
    
    15
    %
 Product revenue
  14




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Parts revenue
 Cost of revenue
   15




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Gross margin
  Research and development
  16




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Research and Development Expenses
 (expressed in thousands of Canadian dollars)
 Fiscal years ended March 312009
    
    
    2008
    
    
    2007Research and development expenses
    
    
    33,003
    
    
    
    26,684
    
    
    
    27,041Program funding
    
    
    (2,021
    )
    
    
    (3,658
    )
    
    
    (5,150
    )Research and development, net
    
    
    30,982
    
    
    
    23,026
    
    
    
    21,891
 General and administrative
  Sales and marketing
  17




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Foreign exchange gains and losses
 Depreciation and amortization
 Interest on long-term debt and amortization of discount
  18




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Interest and other income
  Gain on sale of long-term investments
 Income tax expense
  19




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Joint Venture Partners share of income from joint ventures
 CAPITAL REQUIREMENTS, RESOURCES AND LIQUIDITY
   20




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21




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22




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SHARES OUTSTANDING
  March 31, 2009
    
    
    May 19, 2009Weighted
    
    
    
    
    
    
    Weightedaverage
    
    
    
    
    
    
    averageNumber
    
    
    exercise price
    
    
    Number
    
    
    exercise price$
    
    
    
    
    
    $Shares outstanding
    
    
    32,040,540
    
    
    
    
    
    
    
    32,041,492Share Options- Outstanding
    
    
    1,136,163
    
    
    
    7.32
    
    
    
    1,131,132
    
    
    
    7.29- Exercisable
    
    
    786,282
    
    
    
    7.53
    
    
    
    782,203
    
    
    
    7.48Performance Share Units- Outstanding
    
    
    1,729,970
    
    
    
    N/A
    
    
    
    1,729,970
    
    
    
    N/A- Exercisable
    
    
    597,560
    
    
    
    N/A
    
    
    
    597,560
    
    
    
    N/AWarrants- Outstanding and exercisable
    
    
    1,608,160
    
    
    
    14.68
    
    
    
    1,608,160
    
    
    
    14.68
 SUMMARY OF QUARTERLY RESULTS AND DISCUSSION OF FOURTH QUARTER 2009
   Selected
Quarterly Operations Data (unaudited)
 Selected
Quarterly Operations Data (unaudited)
Three months ended
    
    30-Jun-07
    
    
    30-Sep-07
    
    
    31-Dec-07
    
    
    31-Mar-08
    
    
    30-Jun-08
    
    
    30-Sep-08
    
    
    31-Dec-08
    
    
    31-Mar-09Units shipped
    
    
    533
    
    
    
    867
    
    
    
    801
    
    
    
    519
    
    
    
    1,078
    
    
    
    1,460
    
    
    
    824
    
    
    
    676Average foreign exchange rate (C$:US$)
    
    $
    1.10
    
    
    $
    1.04
    
    
    $
    0.98
    
    
    $
    1.00
    
    
    $
    1.01
    
    
    $
    1.04
    
    
    $
    1.21
    
    
    $
    1.25(expressed in thousands of
Canadian dollars except per share)
Product revenue
    
    $
    11,842
    
    
    $
    16,639
    
    
    $
    15,488
    
    
    $
    11,269
    
    
    $
    21,428
    
    
    $
    34,332
    
    
    $
    25,448
    
    
    $
    21,547Parts revenue
    
    $
    3,888
    
    
    $
    4,530
    
    
    $
    3,822
    
    
    $
    4,058
    
    
    $
    4,081
    
    
    $
    4,680
    
    
    $
    5,606
    
    
    $
    4,715Total revenue
    
    $
    15,730
    
    
    $
    21,169
    
    
    $
    19,310
    
    
    $
    15,327
    
    
    $
    25,509
    
    
    $
    39,012
    
    
    $
    31,054
    
    
    $
    26,262Cost of sales
    
    $
    10,392
    
    
    $
    15,116
    
    
    $
    12,756
    
    
    $
    10,759
    
    
    $
    17,170
    
    
    $
    29,785
    
    
    $
    24,733
    
    
    $
    19,332Gross margin
    
    $
    5,338
    
    
    $
    6,053
    
    
    $
    6,554
    
    
    $
    4,568
    
    
    $
    8,339
    
    
    $
    9,226
    
    
    $
    6,321
    
    
    $
    6,93034
    %
    
    
    29
    %
    
    
    34
    %
    
    
    30
    %
    
    
    33
    %
    
    
    24
    %
    
    
    20
    %
    
    
    26
    %Net income (loss) for the period
    
    $
    (4,724
    )
    
    $
    (4,867
    )
    
    $
    7,401
    
    
    $
    (8,125
    )
    
    $
    (3,463
    )
    
    $
    676
    
    
    $
    (8,928
    )
    
    $
    (12,710
    )Earnings (loss) per share:Basic
    
    $
    (0.22
    )
    
    $
    (0.19
    )
    
    $
    0.28
    
    
    $
    (0.30
    )
    
    $
    (0.13
    )
    
    $
    0.02
    
    
    $
    (0.28
    )
    
    $
    (0.43
    )Diluted
    
    $
    (0.22
    )
    
    $
    (0.19
    )
    
    $
    0.26
    
    
    $
    (0.30
    )
    
    $
    (0.13
    )
    
    $
    0.02
    
    
    $
    (0.28
    )
    
    $
    (0.43
    )Cash from (used in) operations
before change in
non-cash operating working capital
    
    $
    (3,372
    )
    
    $
    (2,645
    )
    
    $
    (3,339
    )
    
    $
    (8,238
    )
    
    $
    (2,548
    )
    
    $
    (3,947
    )
    
    $
    (8,288
    )
    
    $
    (10,842
    )Companys 100% share of CWI net income
    
    $
    1,160
    
    
    $
    2,412
    
    
    $
    8,870
    
    
    $
    (810
    )
    
    $
    3,234
    
    
    $
    2,800
    
    
    $
    258
    
    
    $
    1,540Joint Venture Partners share of CWI net income
    
    $
    580
    
    
    $
    1,206
    
    
    $
    4,435
    
    
    $
    (405
    )
    
    
    1,617
    
    
    
    1,400
    
    
    $
    129
    
    
    $
    770
  23




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Three months ended March 31, 2009 and 2008
     24




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CONTRACTUAL OBLIGATIONS AND COMMITMENTS
 Carrying
    
    
    Contractualamount
    
    
    cash flows
    
    
    < 1 year
    
    
    2-3 years
    
    
    4-5 years
    
    
    > 5 yearsAccounts
payable and accrued liabilities
    
    
    14,359
    
    
    
    14,359
    
    
    
    14,359
    
    
    
    
    
    
    
    
    
    
    
    Demand instalment loan
    
    
    4,642
    
    
    
    4,950
    
    
    
    1,494
    
    
    
    2,568
    
    
    
    888
    
    
    
    Short-term
debt
    
    
    1,614
    
    
    
    1,614
    
    
    
    1,614
    
    
    
    
    
    
    
    
    
    
    
    Subordinated
debenture
    
    
    18,037
    
    
    
    18,037
    
    
    
    1,350
    
    
    
    16,687
    
    
    
    
    
    
    
    Other long-term debt
    
    
    52
    
    
    
    57
    
    
    
    17
    
    
    
    27
    
    
    
    13
    
    
    
    Operating lease commitments
    
    
    
    
    
    
    5,795
    
    
    
    1,734
    
    
    
    2,594
    
    
    
    1,402
    
    
    
    65Royalty payments
    
    
    1,350
    
    
    
    28,189
    
    
    
    1,350
    
    
    
    2,700
    
    
    
    2,700
    
    
    
    21,439Investment in Joint Venture
    
    
    
    
    
    
    5,273
    
    
    
    5,273
    
    
    
    
    
    
    
    
    
    
    
    6,044
    
    
    
    44,264
    
    
    
    9,868
    
    
    
    7,889
    
    
    
    5,003
    
    
    
    21,504
 Contractual Commitments
  Demand Installment Loan
  Short-term
Debt
  Subordinated
Debenture Notes
   25




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Contingent off-balance sheet arrangements
 Government Funding
  AGREEMENT
    
    DESCRIPTION
    
    ROYALTIES
    
    TERMINDUSTRIAL 
TECHNOLOGIES 
OFFICE (FORMERLY 
TECHNOLOGY 
PARTNERSHIPS 
CANADA)
    
    Fund 30% of the
eligible costs of,
among other
research projects,
the adaptation of
Westports
technology to
diesel engines, up
to $18.9 million.
    
    Annual royalties
equal to the
greater of
$1,350,000 or 0.33%
of annual gross
revenues from all
sources, provided
that gross revenues
exceed $13.5
million.
    
    Fiscal 2009 to
fiscal 2015,
inclusive; royalty
period may be
extended until the
earlier of March
31, 2018 or until
cumulative
royalties total
$28,189,000.DEPARTMENT OF 
NATURAL RESOURCES 
CANADA
    
    Funded $1 million
for demonstration
of a low emissions
natural gas power
generator in Grande
Prairie, Alberta.
    
    1% of revenues from
future sales of
natural gas engines
for power
generators.
    
    Earlier of 10 years
from project
completion date
(August 30, 2004),
or when cumulative
royalties total $1
million.
  Business Risks and Uncertainties
 www.sedar.com
  26




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NON-GAAP MEASURES
  Cash flows from operations before changes in non-cash working capital
 (expressed in thousands of Canadian dollars)
 2009
    
    
    2008
    
    
    2007Cash flows from operations:Loss for the year
    
    $
    (24,425
    )
    
    $
    (10,315
    )
    
    $
    (11,307
    )Items not involving cash:Depreciation and amortization
    
    
    1,978
    
    
    
    1,550
    
    
    
    1,410Stock-based compensation expense
    
    
    2,246
    
    
    
    664
    
    
    
    2,089Accretion of TPC warrants
    
    
    
    
    
    
    
    
    
    
    571Future income tax recovery
    
    
    3,245
    
    
    
    (4,691
    )
    
    
    (3,455
    )Change in deferred lease inducements
    
    
    (321
    )
    
    
    (251
    )
    
    
    (164
    )Gain on sale of long term investments
    
    
    (14,275
    )
    
    
    (10,659
    )
    
    
    (8,120
    )Joint Venture Partners share of income from joint venture
    
    
    4,221
    
    
    
    5,564
    
    
    
    6,057Loss from investment accounted for by the equity method
    
    
    1,021
    
    
    
    
    
    
    
    Interest on long-term debt, amortization of discount and other
    
    
    866
    
    
    
    690
    
    
    
    1,663Other
    
    
    (181
    )
    
    
    (146
    )
    
    
    (69
    )Cash flows from operations before changes in non-cash operating working capital
    
    $
    (25,625
    )
    
    $
    (17,594
    )
    
    $
    (11,325
    )
  27