Fellow Z drivers,


I found myself wondering the following:


I went to drive on track (and really let the car have it) a few days ago. Driving on track lasted in total around 1 hour with revs more or less never going under 4k. This was done in parts of 15mins or so to let breaks etc cool off.


Drive home after track about 1 hour, all standard 60mph on 6th gear, didnt notice anything there.


Now the next day I started up my z and drove just around 10mins (in city) to shop and back, noticed that the cars sound has changed to a more "metallic and somewhat bright" sound. Kind of like turning the treble up on radio and adding some metallic effects to it.


My Z has:
aftermarket exhaust (unknown brand)
K&N intake filter
Kinetix Intake Plenum
Brisk Spark Plugs
Rest relevant is stock


EDIT: 350z -04


The basic sound of the car is same, and im not hearing anything too weird from the engine. Could it just be the result of the engine & exhaust getting "cleaner" as the car has only been in slow city -driving for a year before?


Or should I really be worried?


Getting oils changed tomorrow and having a look at the exhaust for leaks.


Thanks,


Zerg

 

Weelcome Zerg- which track did you go to? Was it part of an organized track day or a car club having an outing? AS for the change in tone, it's most likely a small change in the exhaust. When you check your Z, inspect the header flanges and gaskets, as well as the flex joints going back towards the muffler. A small leak at any of those areas will alter the engine note. Also, look for any pinhole leaks on, or near the muffler itself.

 

BTW- I've never heard of Brisk-brand spark plugs. Here in the states, it's common knowledge that NGK Irridium plugs are the way to go to keep your VQ35DE running smoothly.

 

The sound of my Z changed when I broke a motor mount.

The motor was actually making contact with the underside of the front strut tower bar.....very metalic sounding.

 

Thanks for your reply.

It was a local Nissan club organised track evening at Ahvenisto Race Circuit.

Yeah Ill have to do that, thanks. If the exhaust is leaking its reparable and can still drive without too many worries. If the engine mount or something is failing (above poster), it will get..interesting.

Any other ideas? Ill have to check those first ofc.

Many thanks.

This is only a slight change tho, wouldnt it be very significant if the motor changed position?

 

Mufflers have deflectors, ports, holes and sometimes packing inside them. A baffle could have come loose or rusted through, a hole might have clogged with debris or rusted, packing could have settled, or packed in tighter and further away from the ports it was covering.

 

maybe u finally cleared out all that spider webbing that was there, u know

 

This must be it

You should check it out. I did some digging around this when i changed the plugs a year back, brisk seemed pretty solid according to user feedback & reviews.

http://www.briskusa.com/

There seems to be some info for US, dont think the company is US based, but this is just a guess.

 

i had the exact same issue with my motor hitting the underside of the front tower bar, however the mechanic that diagnosed it told me my motor mounts are fine how much did it cost you to replace your motor mounts?

 

I was thinking that maybe a cat came apart internally

 

I had this problem once - turns out it was actually the weather seal on the front windshield developed a slight gap and it sounded just like what you describe.

 

to be serious, it really sounds like a bad exhaust, the mufflers. i have a cheap 200 ebay exhaust, and it sounded nice till i gave it all the car had, after that it started sound as if all the glass packs r cracked lol. so i would put my bet on exhaust muffler. srry if this is a late response and u fixed it already

 

Well.. Seems like the "flexible part" of the exhaust (sry, dont know the name for this in english) started leaking after track and this seems to be the reason for changed sounds. Motor mounts are fine, got them checked by a nissan mechanic while oils changed.

Too much pressure in the exhaust?

This will be pain in the *** to fix as I dont know which bloody brand the exhaust is, nor do I have any..real means.. to lift up the car and work safely under it.

Dammit.

Im kind of interested in Invidia Gemini exhaust (if I can afford it), anyone got experience of this?

I kind of like the sounds on my current exhaust tho, so if it is easily fixable ill stick to what I have.

 

OP, you f*cked up your car.

 

How constructive.

Why is that?

 

I damaged the flex portion of my stock Y pipe not long after installing a cat back exhaust and race pipes earlier this year. I don't know if it was because of the exhaust, race pipes, a pot hole, or it was just time to go, but it was making a sound similar to what you describe. I just ordered a Stillen Y Pipe yesterday. It will be here next week and that will bring my normal exhaust tone back. Go on Amazon and order one unless someone with more experience can recommend a better Y pipe. I wasn't looking to get top of the line- just something better than stock since the rest of my exhaust is aftermarket.

 

Best to ignore ignorant posts that contribute zero to the conversation....

 

OP, I rolled over 300 miles with the invidia on my car yesterday and I am loving it more and more each time I drive it. very stock sounding till you reach 3-4k then it comes alive and sounds great. still debating on putting motordyne art pipes or high flow cats on to give the lower rpm's some more growl but I am still waiting to see how loud the invidia is going to get after it gets some more miles on it. great exhaust for the money welds looked great and fitment was spot on.

 

Thanks for your replies.

Ill see if it is possible to install invidia catback, or if im just going for a fix on my current one.

Very friendly and helpful "help me im stupid lol -topic", ty all.

 

Labor was ~$375.

I also had them replace the transmission mount at the same time. All the mounts are stiffer than stock and it causes the cab to resonate over 4k RPM. (I read that this happens particularly with stiffer transmission mounts, so it may have nothing to do with the motor mounts) It's almost like I have a third tail pipe when I get to the top of the tach. No big deal for track use though.

Also, if you adjust your strut bar too short, it has the effect of lowering the bar closer to the motor. You can actually get it close enough to make contact with the motor...even with good motor mounts.