I had my R/T Cats and NISMO Exhaust installed yesterday. The sound is much louder, understandably so. However, above 4000 RPM's at full throttle the exhaust is very raspy, almost metallic. Does anyone else have this problem? Possibly loose connection or hanger, I'll take it back to the shop and find out. Any input would help.

It does sound good, just a little loud for every day driving. Be cautious if you are planning this upgrade. BTW power is noticeably better throughout the rev band.

Thanks,
Neil

 

The sound will go away after several hundred miles. I did, however, have a problem with rattling of the midpipe and the crossmember. I did some mods that most would not do, but it fixed my problem permanently. Give it some time and the sound does get better. I've seen some people bail out after only a day of driving.......big mistake IMHO. The gains and sound are tremendous with the RT Cats.

 

Since The Z is not my daily driver the noise is not as disturbing. I had been hoping that after a period of time the noise would stop along with the burnt smell. I am glad to hear that it will. For $1650 for the setup with a pop charger, I'm going down with the ship, no bailing out.

Thanks again,
Neil

 

I've had the Random cats on my car for about 4 months. I originally had the Injen exhaust and never had a problem with this noise. But I recently swapped to the Nismo exhaust and now get the sounds. Can't figure out what it is about the exhaust that's causing this noise. It's not the gaskets because I used the ones included with the exhaust which are non-metallic.
Is anyone else getting a weird metallic sound at about 2000 RPM when decelerating (in gear) or when they blip their throttle?

 

I installed the RT cats on my stock exhaust system last weekend. Didn't notice that sound yet, but remember thinking during the installation that the metal-to-metal connection of the cats to the trans bracket might cause some rattles later on. I assume that they get too hot to use rubber grommets in between.

 

you've seen the size of the actual cats....small, almost like straight pipes w/ a bulge. i think thats why you get the slight raspiness up top. it will get better though, but not completely gone.

 

Neil ,

I have exactly the same combo as you (RT / Nismo) which was fitted on Saturday. I liked the sound but there was some serious vibration going on - especially when decellerating in gear. It was driving me nuts and I couldn't decide what it was. I heard heard about the 'rasp' that gets talked about but this was no rasp - more a metal on metal resonance or vibration.

Problem solved.

I took it to a shop today where we were able to put the Z on a lift and get right under it. I was a bit suspicious of the ally heat shielding and thought that might be the culprit. As it is now in pretty much the wrong place (right place for std cats / wrong place for RT's) I ditched them both. This was not the solution.

The exhaust looked fine but we checked the thing with a torch at every point where it was even close to a bracket or whatever. I can categorically (brave but there you go) say that your problem is being caused by vibration with the rear cross bracket. This is the part where the exhaust is sat under the prop shaft but over the black chassis bracket (towards the back end). if you check close , you will see marks where they have been touching. You will also be able to pull downwards on the nismo and make them touch. I can think of two possible answers;

1/. lag that part of the 'zorst with cloth heat sheild to stop the metal on metal contact. (I didn't do this)

2/. Jack the exhaust up as far as you feel is safe. Then fit a jubliee clip to the first rubber hanger that you come to , as you look back to the rear box. If you are stood under the car , it is on your right hand side. Tightening the jubliee clip will take some of the play out of the system and raise the back end of the exhaust enough to stop fouling the bracket. ( I did this)

I am sure there are other options, including messing with the hangers in other ways. However, you need to gain at least 0.5 cm.

The problem is being caused by the extra bore of the nismo.

Regards

 

Spacers...between the frame that you are talking about and the floorpan. Purchased my Nismo exhaust from Jeff@Performance, and the spacers come with the exhaust. Fits perfect. Just loosen the crossbrace, then slide the spacers in. They look like front end spacers from a GM rear drive car's upper control arm...looks like a fork with 2 tines and a tab at the other end. Around 5mm thick.

You are right about the larger OD of the Nismo, it will be very close without any spacers.

 

Hey guys,

Thanks for all of the advice.

I went home last night and looked under the car. I realized that one of the two flange bolts that connects the Y pipe to the exhaust pipe had come out. The gasket had spun down and only being held on by the other bolt away from the flange. This left a 1/4" or so gap at the connection and this was causing the problem.

Took the Z in this morning, they put it right up on the lift replaced both bolt with locktite and lock washer and nuts. SOUNDS GREAT!!!!

This is what it is supposed to be like. Sounds like a 911 but deeper. I'll be putting the pop charger on tonight and can't wait to hear and feel that.

Thanks again to everyone for their input, This is why I appreciate the forum so much.

Neil

 

Who sells the RT Cats?

Thanks.

 

Call Paul at Avalon Racing. I got Cats, Nismo Exhaust, Pop Charger for $1650.

https://my350z.com/forum/showthread....threadid=63626