Project Infiniti G37S: Part 3: Fast Intentions High Flow Resonated Cats and Exhaust

by Aaron LaBeau

Exhaust upgrades have been a huge disappointment for me over the years.  I can say without a doubt that the dollar to satisfaction has to be the worst or greatest depending on how you like measuring disappointment.  I’ve either had exhaust’s that sound great but make no power or make power but beat your eardrums to death with droning at cruising speeds on the highway.


As listed on the product info sheet all flanges are welded on the inside and port and polished (shown below).

After pouring over forums and websites the only company I kept seeing the words 'you won’t regret it' for the G37 was with Fast Intentions.  While there are others in this market that make a great product it seems with exhausts you need to make the choice of compromising comfort in terms of interior noise for that last bit of horsepower.


Behind the scenes at Fast Intentions for the exhaust assembly.  As true craftsmen they take their time and as such this kind of work takes time.  From order to delivery was a 6 week process but delivered in that timeframe as promised.

Fast Intentions hand builds all of their exhaust systems in house at their shop in Simi Valley, CA. Stating that their cat back exhaust system is the ‘premier upgrade for all G35/37 owners’ they are effectively throwing down the mic.  Their goal with this system was to enhance the sound that Infiniti created from the factory by making the exhaust note deeper, smoother and louder.

Their X-pipe is designed to increase low end torque and maximize power throughout the entire RPM band.  The exhaust note is quiet at idle but people will know the car is modified.  Startup now has its own unique growl, skip to the end of the article if you must.  At wide open throttle it really comes to life in an aggressive way without being abusive to the ears.  When it came down to ordering the exhaust I was impressed by all the options available and considerations Fast Intentions made for the G owner.  

Fast Intentions offer variations between manual and automatic and RWD or AWD in their options having to do with the various pipe shapes and sizes as the exhaust is routed.  An option of 2.5” piping over their standard 2.25” piping for forced induction applications is also available.  Finally, and most importantly, their X-pipe is offered straight through, or with 12” or 18” resonators.  For those of us who daily drive our cars this last option is super important.  Eyeballing the comparison between the stock exhaust and the FI exhaust it looks like they kept the resonator as close to the factory location as possible.  Infiniti certainly did their homework in terms of reducing NVH and FI smartly followed this template while increasing exhaust flow.  The FI system is a true dual exhaust system unlike the original Infiniti exhaust that merges 2-1 and then splits back out to dual at the factory X-pipe.


The stock exhaust while comfortably quiet; didn't have the performance sound we wanted so off it went.


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Thursday, May 12, 2016 12:37 AM
Torque converter? Automatic?
Thursday, May 12, 2016 5:58 AM
Thursday, May 12, 2016 9:21 AM
Why not reinstall that brace with spacers?
Thursday, May 12, 2016 9:38 AM
I agree with Super, that brace should be reinstalled. Losing chassis stiffness would suck. I'm surprised they don't give you the option for a new/modified one.
Thursday, May 12, 2016 9:52 AM
@Supercharged - Good idea! But honestly this isn't anything I believe I'll ever notice. All you MotoIQ purists though, you'll see me driving down the street, point and mock me for compromising the body rigidity. ha!
Thursday, May 12, 2016 10:42 AM
But think of the weight you saved.

Only one way to know for sure: Do laps around the neighborhood with it off and with it installed and compare lap times.
Thursday, May 12, 2016 10:50 AM
@MDR - My friend George called those BS brackets. I just tried a lap and the neighbors were much more pissed as I drifted past their house with the bracket on. I'll try another with the bracket off and see if their mood improves...
Thursday, May 12, 2016 5:46 PM
For the brace, a couple spacers could be machined. Or just a run to Home Depot for some washers :)
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