SecProbe.io

January 31, 2013

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.
Amendment No. 2 to Form 40-F for the Nine Months  Ended
  December 31, 201 1
Filed October 29, 2012
  File No.  1-34152

Dear Mr.  Demers :

We have reviewed your letters dated January 3, 2012 and December  19, 2012  and filings
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 this letter within ten business days by providing the requested
information  or by advising us when you will provide the requested response.  If you do not
believe our comments apply to your facts and circumstances, please tell us why in your response.

After reviewing the information you provide in response to these comme nts, we may
have  additional comments.

Amendment No. 2 to Form 40 -F for the Nine Months Ended December 31, 2011

Exhibit 99.2

Note 21. Inves tment in J oint Ventures

(a) Cummins Westport Inc., page 37

1. We have considered your prior responses, in cluding comment 3(a) on September 25,
2012, comment 1 on October 29, 2012, and comments 1 and 2(b) on December 19,
2012.   To help us better understand your conclusion that CWI is a VIE, please address the
following:

Mr. David R. Demers
Westport Innovations Inc.
January 31, 2013
Page 2

  Given that the total assets of CWI as o f March 31, 2008, the earliest period
presented in the Form 40 -F are $34 million and Westport contributed $38.4
million, please tell us why you believe you met FASB ASC 810 -10-15-14a, as it
appears by design that sufficient equity is at risk.
 Given that We stport holds equal representation on the board with Cummins and it
appears that returns are not capped, please tell us why you believe the company
met FASB ASC 810 -10-15-14b.
 Given that the relationship of voting rights to economics in CWI is not
disproportionate, please tell us why you believe the company met FASB ASC
810-10-15-14c.

2. Further to your response to comment 4 in your December 19, 2012 letter, please further
explai n why you believe that Westport has the “authority to direct” the activities of CWI
that most significantly impact CWI’s economic performance.   In this regard, discuss the
source of your authority and whether it is pursuant to the joint venture agreement o r just a
business practice.

3. Also, it is not clear why you believe that the activities Westport has the authority to direct
(product management/sales and marketing/market penetration) are more significant to the
economics of the VIE than the activities of CWI that it appears Cummins has the power
to direct , such as manufacturing and distribution.   For example, in your response to
comment 6 in your December 19, 2012 letter, you noted that Cummins provided its
engines at cost to CWI.   Please explain why you b elieve this can be easily outsourced or
replicated by another OEM.

4. Further to your response to comment 8 in your December 19, 2012 letter, we note you
consider the unanimous rights listed in Appendix A to be protective rights and not
significant participa ting rights.   Please tell us why you concluded that unanimous
approval of actions such as those related to compensation, the annual operating plan and
the appointment or removal of officers do not represent significant participating
rights.   In your respon se, support why you believe that the board is not a substantive
decision maker and how all significant decisions are made at the management level.

5. Further to your response to comment 7 in your December 19, 2012 letter, please tell us
the terms of the join t venture agreement that support your conclusion that Westport bears
the risk of CWI due to your control over the outcome and the allocation represents the
distribution percentages based on a weighting of the activities that were determined to
have the mos t significant impact on economic performance.   Please also discuss whether
any amounts are owed or have been paid as a performance bonus and whether the amount
is substantive.

6. Please explain how you resolve with Cummins any disagreements or deadlocks with
respect to CWI.   In this regard, please briefly describe methods of past resolutions.

Mr. David R. Demers
Westport Innovations Inc.
January 31, 2013
Page 3

You may contact Gary Newberry, Staff Accountant, at (202) 551 -3761 or Kate Tillan ,
Assistant Chief  Accountant, at (202) 551 -3604 if you have questions regarding these comments.
In this regard, do not hesitate to contact me at (202) 551 -3671.

        Sincerely,

        /s/ Kate Tillan for

        Martin James
        Senior Assistant Chief Accountant