370Z / G37 / G35 High Flow Metallic Catalytic Converters

Definitely feel a difference, very happy !

We are about to install. Thanks for checking on us

Sounds aggressive at higher rpm revs , quality built .

They Sound Great and still close to factory. Just what I was looking for. Thank You David

5000+ amazing miles with these maama-jaamas on the G37x, the engine sound really comes to life. Mind you I only have 1 bolt-on, minor exhaust work and a gauge tuner for the rev/speed limiter. Stock everything. You don't realize how loud this is until your first winter cold start and it just claps! Throaty on spirited driving especially paired w/ CAI's, and light burbles(depending on your exhaust), and more aggressive mid-hi range. Worth the $ for this, it feels very hi-quality. NON-negotiable, get the gaskets Z1 offers and not the ones it comes with. I swear you'll thank your self immensely when you don't have an exhaust leak to deal with. No CEL's thrown and oh spray penetrating lube on the bolts a week before you plan to install, saves quite a bit of that elbow grease. 10/10 would recommend!

Great Quality. Great Sound. Love them

Good high flow cats.

Replaced stock cats with these 8/2020. Enjoy the sound my car makes, currently paired with stock exhaust. The part did thow a SES light, but an ECU reset was able to clear it long enough for an emissions test. Wish z1 offered an option for o2 sensor extender in addition to heat wrap

A must if your doing your exhaust , the high flow cats really add the power not just noise !

These sound good does have a raspy brrrrrt at 4K but it’s worth the extra HP

Make the rasp sound and threw CEL shortly after installed on 2014 Q60s. Noticeably better performance than stock not tuned.

Perfect fit and sound amazing. Waiting on tune and dyno

Great product! Very knowledgeable and helpful staff. Will be buying more products for my Infinitis.

They were a direct fit , no cutting or welding needed ! These cats are a perfect mod if you’re looking to deepen the tone of your exhaust , get more hp & better acceleration.

Overall a great product with low rasp and no check engine light, although the gaskets do not fix this product correctly so i had to buy my own :/

I’ve had these for just about a year and put them through h*ll. I would recommend these to anyone in the market. The welds are very high quality.

My first time at installing these in my garage by myself. After approximately 36 hours in total and multiple stops at the local auto parts shop for better nuts and bolts, I installed them. I applied heat wrap to the converter part and the upper part of the pipe. The performance difference is felt immediately. In combination with my long tube cool air intakes, the gain in HP, especially past 4000 RPM is very obvious. The engine has become alive. They have lasted well for a year, very robust build. 4 stars for 1. included bolts have weak grooves and warped right away, had to buy a new nuts and bolts. 2. They have rasp at 2-4k, if taking off fast and especially when cold. When completely warmed up, less rasp and somewhat tolerable. Some drone, which I actually enjoy.

High-quality cats and sounds great! However, it did cause my CEL to come on.

My check engine light came on after installing HFC. The up side is the car sounds a lot better

Really good quality, they do rasp a bit, but with the right exhaust they will sound great! And you can feel the power in top end.

Fit good, added with aftermarket catback. Eventually did throw CEL, Slight rasp at 3500 rpm, as others stated. Good Sound.

Purchase these a couple days ago for my 2015 to q70s Very impress

Bought them for my 08 G37. Perfect fit. No CEL. Sounds great even after almost a year of use.

These will free up a little power (better with a tune), lose some weight, and add a little volume to your aftermarket exhaust. I have the Stillen exhaust and they sound good. There is a quick rasp at around 3,500 rpms, but they car sounds great overall. I got no CE lights for quite a while, but they eventually did start throwing codes. Not a big deal for me as I was planning a tune anyway, but keep this in mind if you do not plan to tune the car. I have a '13 G37S sedan 6spd.

The cats I received looked a bit different as the HFC's were smaller and the secondary bung was extended parallel to the pipe a few inches. Fitment with the Z1 headers was near perfect, some washers and a little tweaking to line the factory tie in bar. Some relief cuts on the Stillen cat back just behind the flanges to line them up without forcing them together and overstressing the pipe (that's how you crack stuff). I did however get frustrated with the buzzing. Let it be known that I was able to eliminate my header/HFC buzz, keep a really deep growl at idle, preserve most of the beautiful VQ exhaust note and without losing more than I can count on one hand's worth of power, if any. I bought 50 Feet of DEI 1200 degree exhaust wrap, $48 Advance Auto. Cut it in half and double wrapped both HFC pipes from flange to flange. Then I cut in secondary HFC's for both banks immediately after the midpipe to HFC pipe flanges, no more than 5-6" of substrate. After a good cook in period the buzz is all gone, even when it's cold. Idle is a mean deep growl, and there is no drone at all. It's very tame between idle and 3k now at normal accel (2-3k seems to be the problem area for the buzz) but comes to life with any decent amount of throttle, the more you give it the more it sounds like a proper VQ! This was how I conquered the buzz with my old DE and this, my VHR.Don't be afraid to purchase such amazing quality parts for fear of unwanted resonation! It's much easier to kill than you think!

Gave these hell for almost 2 years, no issues with hfc or gaskets. Highly recommended.

Sounds great. No cel light in almost a year of daily driving. Min rasp/hiss. Great overall quality