SecProbe.io

Mail Stop 3030
September 23 , 2015

Via E -mail
Mr. David R. Demers
Chief Executive Officer
Westport Innovations Inc.
Suite 101, 1750 West 75th Avenue
Vancouver,
British Columbia, Canada V6P 6G2

Re: Westport Innovations Inc.
 Form 40-F for the Fiscal Year Ended December 31, 2014
Filed March 9 , 2015
Amendment No. 1 to Form 40-F for the
  Fiscal Year Ended December 31, 2014
Filed July 23, 2015
File No. 001-34152

Dear Mr. Demers :

We have reviewed  your September 17, 2015  response to our comment letter and have the
following comments.  In some of our comments , we may ask you to provide us with information
so we may better understand your disclosure.

Please respond to these comments  within ten busine ss days by providing the requested
information or advis e us as soon as possible when you will respond.  If you do not believe our
comments apply to your facts and circumstances, please tell us why in your response.

After review ing your response to these  comments, we may have additional comments.
Unless we note otherwise, our references to prior comments are to comments in our September
3, 2015  letter .

Amendment No. 1 to Form 40 -F for the Fiscal Year ended December 31, 2014

Exhibit 99.2

Report of Independent Registered Public Accounting Firm

1. We note your response to prior comment 1.  Please address the following:

 Please clarify for us whether your auditors undertook any inquiry or carried out any
auditing procedures relating to your financial statements after March 9, 2015 as a
result of the errors noted in the financial statements of the equity investee.

Mr. David R. Demers
Westport Innovations Inc.
September 23 , 2015
Page 2

 Given t he change in management’s conclusion on the effectiveness of the company’s
internal control over financial reporting subsequent to the original date of the
auditors’ report on the financial statements and the resulting reissuance, dual -dating
and change in  the audit firm’s opinion on the company’s internal control over
financial reporting, please tell us how your auditors were able to conclude that the
company’s financial statements did not need to be revised without undertaking
inquiry or procedures. Refer  to paragraph 6 of PCAOB AU Section 530.

2. Notwithstanding the above comment, we note that the accounting firm’s attestation report
on internal controls over financial reporting may be confusing to investors since the
report refers to the firm having issued  a dual dated opinion on the financial statements.
The last paragraph says, “…..our report dated March 9, 2015 (July 23, 2015 as to the
effects of the material weakness described in Management’s Report on Internal Control
over Financial Reporting (revised )) expressed an unmodified opinion on those financial
statements.”  Please amend the Form 40 -F to include an audit report on internal controls
over financial reporting that refers to the correct date of the audit report issued on your
financial statements.

3. We note your response to prior comment 2.  Given that the audit of your financial
statements was conducted in accordance with Canadian generally accepted auditing
standards and the standards of the Public Company Accounting Oversight Board (United
State s), it unclear why you did not also provide a reference to an unqualified opinion
under AU 508.10.  We note that an “unmodified opinion” is not a term defined or used in
the standards of the PCAOB. Please have your auditor revise its report in future filin gs,
including any amendments to this filing, to clarify that its opinion on your financial
statements was also unqualified.

You may  contact  Eric Atallah at (202)  551-3663,  or, Jay Webb, Senior  Accountant,  at
(202) 551 -3603 with any questions.  You may  also reach  me at (202) 551 -3662.

Sincerely,

 /s/ Jay Webb for

Kevin Kuhar
Accounting Branch Chief
        Office of Electronics and Machinery