I did a search and didn't find the answer but if it has, sorry for the repeat question?

1. Would I be able to pass smog?
2. Any HP gains or is it only for sound?
3. If I didn't want to invest in a full dual exhaust system would this be my next best alternative?
4. Looking for a deeper sound but not real loud at cruising speeds. Which model in your opinion would give me that nice deep sound without the drone.

I'd appreciate any input or suggestions as to a better alternative.

 

Fast Intentions=HFC's they are having a special too...You would be able to pass sniff but you cant pass the visual part of the check. there are good hp gains on it too...

 

The gains don't feel noticable... But it's noticable at the track... I ran a 13.8 at 104 with intake, kinetixs hf cats, and MREV...Just with intake was 14.0 at 100... But i am burning alot of oil because there is hardly any back pressure...

 

Do you think just the lack of back pressure would cause more burning of oil? How much more oil do you burn since you installed the HFC? Sorry for the dumb question but aren't all the aftermarket dual exhaust systems lacking a true cat? If this is the case everyone running a HFC or a dual exhaust system are all burning more oil or is there something different about a dual exhaust system?

Thanks for the response. I want to do the right thing for me and I'm learning alot from everyone here that are much more knowledgeable than I.

 

I gotta another dumb question...........well then how do you get pass the smog check?

 

I've heard other guys on the forum say that they've run into the same problem... I had the kinetix hf cats and was burning about 1 court every 1,000 miles... They say u can use a thicker oil, but i just took the cats off... I wanna get a set of hf cats that have a mounting brackets.,... kinetix didnt have a bracket... Mine also rattled hella bad... I had them worked on like 3 times and the rattle kept coming back... Heat sheild was vibrating... i just got tired with it... I think i might get random technology cats or just get the fast intenition resonated test pipes... For the smoging, just save ur stock cats and if it doesnt pass with the high flow, then switch them out...

 

Just my .02 worth.
I would 'cya' it by removing any mod that's not CARB approved before smogging.
You don't want to fail your test first time around, goes into DMV records via computer link at the test site immediately.
Plus you'll have to pay more $$ for a second test.

 

$400 install?

I can swap out both cats in 30 minutes, including lifting the car on jackstands.

$400/.5hours = $800/hour

Damn, I need to be in this business.

The cats are the single biggest bottleneck in the flow of the OEM exhaust system. They are a very worthwhile upgrade, especially if you plan to keep your car NA. In conjunction with headers/tuning, I gained 29RWHP that my Crawford Cats played a big part in.

 

It's not $400 to install cats... I had my cats put in for $150... Thats robbery if u paid $400... And the gains are there... Atleast track wise it helped me out... With intake, MREV, and hf cats i ran a 13.8 @ 104.... And after every mod i'd head to the track to see if there are any gains... Gains showed up, but daily driving the G felt slower...

 

800/hour?! Where?

I'm gonna have to quit my job and install cats for living.

 

400!?? thats crazy i would be rich..but i got quoted for 75 bucks for an installation of the hfc's FI are good ones casue they dont have a heat sheild...mark4x4 if you dont want to fail just get your mechanic to put on your stock ones again and besides 1st 5 years for the car you dont need to smog it..i got an 04 so i got another 3 more years to go..

 

Well, all in all, hi-flow cats can help a bit considering how restrictive the stock cats on a G35 are. If you're willing to sacrifice a little raspiness in noise, a pair of test pipes are the best bang for the buck though as the performance gains are definitely noticeable. But IMHO, for a street car, a pair of performance cats and a y-pipe will go a long way.

 

Thanks for all the great info! I'll have to rethink if this is the direction I want to go in. I appreciate all the response because now I have a much clearer idea of what to expect. The main issue for me is passing smog, if I knew I could pass smog I would get HFC in a heart beat. I'm talking from the stand point of being reponsible to our air quality not just getting around DMV.

 

basic the thing with the visual test is to determine if it looks.. well.. oem.. if you have a nice shiny chrome hfc there than that is a dead giveaway that it did not come with the car since stock oems are butt ugly.. however the kinetix hfc and i know a couple others uses cats that are "stock" looking so any smogger would just look at it and think it came with the car.. i have kinetix hfc and i'm not too worried.. take it to any muffler shop.. they charge you an hr's worth of labor to install it which is normally $60-$70.. whoever paid $400 got raped.. i've had no problems with burning oil or anything.. been running fine in my car for over 1 year..

 

Oops my mistake. This is why you don't post at late hours.. I was totally thinking of headers we did recently, hence the hundreds of nuts and bolts. Yeah that would be fun if we could get $400 for an hour's worth of work, if that. But yeah, for headers, average about $350-$400 and a pain in the #*&! Thanks for the catch Boris and of course the light humor as I could only expect.