diff --git a/lib/coffee-preprocessor.js b/lib/coffee-preprocessor.js
index 70a34d1..dc31f4d 100644
--- a/lib/coffee-preprocessor.js
+++ b/lib/coffee-preprocessor.js
@@ -4,10 +4,11 @@ var fs = require('fs');
 
 function CoffeePreprocessor(options) {
   this.name = 'ember-cli-coffeescript';
-  this.ext = 'js';
   this.options = options || {};
 }
 
+CoffeePreprocessor.prototype.ext = coffee.prototype.extensions;
+
 CoffeePreprocessor.prototype.toTree = function(tree, inputPath, outputPath) {
 
   if(this.options.lint || (this.options.lint !== false && fs.existsSync("./coffeelint.json"))){