Well, based on the postive responses here, I'm going to do the grounding mod.

As for the roughness, I'm only at 200 mi so far, and I can say that as delivered from the dealer, the engine was shockingly rough. It felt like a truck engine! But as I drove it more, it is now smoother, and it continues to smooth out with each passing day. It also revs easier too. I haven't passed 4000rpm yet tho. I'm hoping that ultimately it will get a lot smoother.

On a side note, since this engine is so raucous, I might as well get a nice sounding aftermarket exhaust!

 

Jason,

Nissan actually released a grounding kit shortly after the car was released. VERY expensive but makes a solid difference.

Note that engine grounding is quite crucial to ECU operation and directly effects driveability, performance etc. All engines are grounded at multiple points in an attempt to normalise voltage to a constant as well as reduce noise by having more grounding points.

In this case "more is better" is the rule however you get to the point were your return falls away.

The idea of the grounding kit is to reduce noise to the ECU and by adding the grounding kit you will improve driveability and some people are getting minor hp increase.

Poor grounding can cause engine misfire, hesitation, unstable idle, poor fuel economy and more. Very simple to test with a multimeter and check resistance before and after kit.

My previous S13 Silvia had idle issues and missed under load. One of the issues was a grounding wire that was too thin and connected to a painted section of the engine chasis following engine refit. We changed the guage of the wire and grounded to a different point and fixed the problem. We found it by looking at the resistance of all grounding points.

The point to look at is whether its worth paying a fortune for a Nismo or HKS kit vs the benefit. Probably not but Insanamine makes a top mod for little dollars.

Just try it.

Mike

 

Quick update for everyone:

I drove the car some more last night at WOT/high rpm and it seems to have smoothed out a lot on its own. I think that in the morning, since it was the first couple of times that the engine got to breathe to full rpm, there may have been some carbon deposits or manufacturing flaws that needed to be cleared out. Now it feels much, MUCH better. It was raining so I'm not sure if the rattle was still there because there was a lot of ambient noise inside the car (I'm still getting used to the relative lack of sound insulation compared with the 323i - in the rain it seems like the rear hatch is not fully closed because I can hear the tires kicking up water in the wheel-wells right behind me). Anyway, I'll need to drive it some more in better weather to see how things are going but I am very encouraged by this latest experience.

Oh and also, the car is actually nice and fast - quicker than I had expected from tooling around during break-in. I'm enjoying the car more every day.

I'm still a little bit skeptical about the grounding kits but you guys have convinced me to investigate it further. I'm not concerned about the cost so much but I just don't want to be the guy that bought the pure-marketing product that doesn't have any benefit. As a driving school instructor, I have a reputation to maintain for sticking to mods that actually do something

Thanks again for the help and opinions.

Jason

 

Jason,

I know what you mean. Also, as an engineer I should be able to explain why I did a certain mod. Something other than, "it might help somehow" would be good. I agree that a grounding kit will not hurt - and they do look good.

Perhaps we could present our case as either (1) it's a backup grounding system to ensure performance and efficiency during all conditions, or (2) it's an electrical research project to determine the benefit of such systems. Is that weasel-worded well enough?

Wayne

 

I was in the same boat, but hey...anything less than $100 is worth a try! It's an easy DIYer. My girlfriend did it with me..... ......and she actually felt the engine run smoother afterwards.

I also compared my car with a stock car (in one of the meets side by side), and my engine idles lower and revs up much smoother than the stock car. The other guy was impressed.

On a side note, I used to drive an E36 M3 (98), and yes the bimmer engine is much quieter. Think of it this way, some have been critizing that the M3...which is supposed to be a sports car...to be too quiet. I guess in other words too refined. Our Z is a true, raw, sports car. It is supposed to be noisier. If you want a quiet Z, Nissan can probably slap on a pile of sound proofing, but the price will go up as well. For a sports car, I think the Z is doing just fine. My $.02.

Anyways, give the grounding kit a try!