Trey,

Did you get to climb under your car to look around?

Can you compare yours to mine?

http://pics.jasonw.net/ExhaustProblems

 

My coupe also got the problem,I am gonna take it to the shop for silight modification on the aluminum shield

 

Jason
I did get to spend a fair amount of time underneath the car. I don't have the pictures on me, but I can tell a few things after looking at your pictures.

Forgive me for stating the obvious:

The first thing I notice is that your driver's side cat is rubbing against the frame of the car(obviously, the whole point of this thread right?). When comparing the gaps from the cats to the transmission, there is quite a larger gap on the driver's side than on the passenger side. On my car, the gaps appear to be visually uniform(did not actually measure). My driver's side cat does *not* rest against the frame of the car.

When I looked at some of your other pictures, I notice that the ypipe is not centered along the transmission tunnel. In fact, it is noticebly favoring the driver's side. Because the ypipe does not have a hangar(it's supported by the cats and midpipe), that tells me that something is "pulling" it to the driver's side, as evidenced by your cat.

The fact that the ypipe favors the driver's side doesn't provide an answer, it just reaffirms what you already know; that there's something funny going on. My best guess is that the stock exhaust manifold/header on your driver's side is the culplit. I don't see how exactly, but that's my guess. Take it for what you will; I am by no means an automotive expert.

Maybe the driver's side exhaust manifold is faulty from the factory, but within tolerances. Maybe it's fractionally shorter. Maybe it torqued too tight(though I can't see how that would be the case). Take a look at that, and see what comes next...

 

buying high flow cats is useless to me, i mean its an oxymoron to begin with, just buy some $100 dollar test pipes off of ebay and throw them on, thats what i did with my 04 sedan and no problems, these people are selling you basically stock parts for A LOT of money, either open it up (test pipes) or keep the stock cats....

 

My hi-flow cats netted some decent gains in performance over *stock* and I can still pass a visual inspection and a sniffer test.... not to mention no raspiness

 

+1 - Yep

Lou

 

<rant>

Not to mention taking care of the environment.

Geez, people. Test pipes vs. hi-flow cats... maybe a few HP difference? I don;t think you realize how much worse a cat-less sytem pollutes - about 100 times worse. Yep - your car with test pipes pollutes as much as 100 other cars with proper cats.

I'm not a tree hugger, but the environment is going to ****. Time to grow up and be responsible. Notice any strange weather patterns or hurricanes recently?

</rant>

 

i have a g35, but had the same issue with the crawford CAT touching the underside of the car.........took me a few tries to get it all sorted out......i first used a crowbar and bent the drivers side heat shield up and away from the CAT.....at the same time i used the crowbar to flatten the ridges on top of the crawford CAT heat shield.....this helped but still had a vibration at WOT....i next removed the drivers side heat shield........helped a little more, but still vibration at WOT........so i took the CAT back out and used a hammer to flatten those ridges, and used a cresent wrench to bend the side of the CAT heat shields.....also, took a hammer to the under side of the car and made a nice dent in the body panel.....put the drivers side heat shield back in and installed the CAT....no more vibration.

a lot of work for a "bolt-on" part.......i know some have said they have installed the CAT with no problems, but i sure had to do a lot of work to get them to work correctly.......

 

The underside of the G and Z should be the exact same near from the front seat forward. Also, Nissan/Infiniti isn't going to make a different chassis/frame rail system for each tranny. From the pics, it's quite apparent there isn't enough clearance on the driver's side. What I'm seeing is a weld/jig problem. There isn't anything wrong with the car, it's the part. When you've got manual labor using a jig to assemble the parts, there will be problems. The fact that Jason got two defective units tells me Crawford either needs to retrain his welder or rework the jig so that the cat heatsheild flanges are oriented more vertically. Like Jason stated, I too don't understand how and why so many aftermarket companies have QC problems like this. Even 1/2" clearance for an exhaust really isn't enough. At least 1" is the accepted industry standard. The engine and tranny torque quite a bit under load. Trying to gauge engine movement while revving the engine under no load won't show realistic engine movement because the engine isn't sending the load through the drivetrain. Engines move A LOT in their mounts when you snap the throttle and shift. Another thing to consider is the weight of the exhaust. From the manifolds down to the muffler, the system weighs in the neighborhood of around 120lbs. That's a crapload of weight that's only supported by a few manifold bolts, a flimsy cat cross mount, and some rubber hangers. During hard acceleration, bumps, turns, and braking, the exhaust system is shifting around. All this movement necessitates good clearance. Sure, Nissan/Infiniti could make the mounting points stronger, but more NVH would be introduced through the chassis and most owners wouldn't stand for that.


BTW, I am glad to see that Crawford is using the stock cat cross brace. From what I've gathered, the aftermarket hi-flow cat setups get rid of the forward "precats" and just use a set of higher flow standard cats. This is similiar to what we did with our 95-98 Maximas. We'd replace the stock y-pipe that had two imbedded precats and install a y-pipe with no precats. The stock main cat was left inplace (just south of the y-pipe). Y-pipes gained an Honest to God 12whp/15wtq on the 95-98 Maxima. I've researched and researched, but I can't find any real data supporting the gains from the G/Z hi-flow cat setups. All I read is heresay. Can someone point me in a direction to find the real gains for these things?

 

I've never seen hard proof as to gains. However, when I was in the market for cats, it was in the interest of a better sounding exhaust. That's exactly what I got.

You know about my new personal-best time. Did my kinetix afford me that? No; weather, experience, shifting, etc all helped me improve my time. Any effect the cats had were negligible IMO. But damn they sound good.

 

Been ignoring this for a while.

Crawford got back with me. Said that since the cats fit Trey's car that I am SOL (read stuck with the problem).

He asked me to send the replacement cat back to him and I declined. I would be out close to $400 and A TON OF FREAK'N TIME.

I still don't know what I am gonna do. I kinda want to take them off and cut them into little pieces. The cheap side of me wants to make it work since I spent all that cash ... but what can I do when the maker says nothing is wrong with his product.

Going by these forums, every single person that has them had to MOD a heat shield or 2 to make it work.

Trey, everything is centered on my car. Maybe the angle of the picture is making it look off. If it wasn't centered ... how would the tranny brace line up to the cats? Besides, I took it to the dealer and they said nothing was wrong with the car but those cats.

No I am rambling ...

 

I've got a 2005 sedan... didn't you say you have access to a garage/lift?

I'll be glad to donate my car/time and we can see if they will fit on my car...

That should give a good comparison of if it's your car, or the cats... seems like a good idea. I used to work in the performance biz... so have a good bit of experience with this stuff.

Lemme know.

 

i wonder if somebody in new orleans is going think this same thing and sue vortech for causing katrina. this is america... anything is possible.

 

Jason

Seems like you ought to take him up on this. It seems to me that with a hammer, enough heat, and bending equipment anything can be made to fit anything. However, with the Crawford Cats, the majority of us had them slip in with no issues. Have you tried a good muffler/exhaust shop with experience in these kinds of things. These kinds of shops custom build exhaust systems for all kinds of vehicles every day. Making these fit should be a no brainer for someone that knows what their doing.

Lou

 

Just an FYI - not 100% on point, but it's related. We don't sell the Ultimate Racing cats for a G35 (sedan or coupe) for this exact reason -they don't fit. The cars are close underneath, but not identical.

your best bet IMHO is using the cats themselves, and redoing the piping yourself to take care of any clearance issues, or, just sell them to a member with a 350Z

 

that blows a major goat.

 

You have no RIGHT to not send that cat back to crawford when it isn't there fault. They tried to help you. You have issues with your car that is obvious.

I would recommend to anyone in the future if you don't send that cat back, to not help you anymore. (or maybe even ban you). That is down right dirty.

 

This kind of transaction makes it just that much harder to get help for other people who have real problems with the products....

 

I don't think you're completely out of luck with the cats. Have a reputable exhaust shop reconfigure the cats to make them fit.

 

G35_TX, (and everyone else)

You must not have read the entire thread.

1. I called Crawford before purchasing these cats. They told me over the phone that these cats would fit my car. So I moved on them and made the purchase.

2. I installed the cats and the rubbing began. I called Crawford and told them the story. First, he didn't beleave they were Crawford cats so I took pictures. He agreed that they were Crawford's and sent me a replacement. Kudos.

3. The NEW cat had the same problem, so they blamed my BRAND NEW car.

4. Took it to the dealer, no problems.

5. Decided to keep the cats until I had time to have them repaired.

6. Took it to a muffler shop today and he backed up what the dealer said and what I knew. NOTHING IS WRONG WITH MY CAR. The cat was NOT designed to fit a G35 Sedan. They were made for 350Z's.

Crawford should NOT be telling people that these will fit a newer (02/05) G35 Sedan AUTO. I know someone here has a 6MT Sedan with an 04/05 production date that says they fit him just fine. Two totally different transmissions.

So I am NOT in the wrong for taking a replacement cat for a defective product and spending another $50 to have them fixed (read modified) to fit my car.

Yes, they TRIED to help but their product is not meant for my car so they shouldn't tell anyone otherwise.

CASE CLOSED.