Sorry, if this has already been covered ad nauseum - it's tough to search for these terms...

I have 1200 miles on the Z (I have had it for 7 days!) and have started using full throttle and full rpm. Coming from a BMW 323i I'm impressed by the power but totally underwhelmed by the roughness of the V6. Where the BMW inline six was turbine smooth until redline, the Nissan V6 is loud, raucous and actually audibly vibrates the dash from 5000-6600rpm. I wonder if it will smoothe out over time. I will get my first oil change to synthetic this week and hope that will help.

I don't buy the grounding kit arguments because I just don't see how that would help.

My questions are as follows:
- Do your engines have as much roughness and vibration as I am describing?
- For the high-mileage guys, is there an improvement over time?

Jason

 

maybe u need an oil change? mine felt alot smoother right after it

 

I know you don't buy it, but I am at 8000 miles and the only difference I got was form the grounding kit, give it a shot do it yourself for 40 bucks or buy one for 100, cheap mod.

 

An I6 is inherently more balanced than a v6. I don't buy the grounding theory either.

 

The BQ engine has won several awards. However, as one magazine put it, the engine puts out truck-like torque at all RPM levels, but also produces truck-like noise. They also say that the sound from the exhaust is much superior to the sound inside. What counts is the result, and at the track the VQ engine provides linear response and fast acceleration out of slow turns that would bog down a low-torque motor. It is noisy though!

 

Thanks for all of the responses. This is helpful.

If the behavior of my engine is normal and raises no reliability concerns, I can learn to live with it. What worries me is that the vibration that I am feeling seems to be more than what is considered "normal" for this particular V6. Do you guys feel a perceptible vibration in the dash (and accompanying dash rattle)?

My dash tends to rattle over bumps (particularly when the car is cold) and also does it under full throttle/high rpms. I'm trying to track down the rattle and fix it because that aspect is my biggest issue with the engine roughness.

Jason

 

The only vibration I get is a slight oscillation at idle and its only after the car's been running for a while. I don't notice too much at high RPMs, but I'm probably busy creaming my pants then... lol

 

One of the first things I noticed about the VQ was its roughness in the higher RPM range. I too was skeptical about the grounding kit, but for $40, it was worth a try. It very noticably smoothed out the roughness in the upper RPM range. Give it a try, you won't be dissappointed.

 

I second that. I just put in the grounding kit this past Saturday. I was skeptical that this mod would make any difference, but it is noticeably smoother as I drove to work this morning. Parts came out to approx $60. $20 of the cost was the hammer crimper. I highly recommend the hammer crimper for low gauge cable; works awesome.

 

No offense or anything, but are you sure its not just a placebo effect? I may try it anyway, since its not much cash, but I'm really skeptical about perceived effects vs. real effects.

 

Trust me, I was thinking the same thing when I was reading about the grounding kit awhile back. I bought the parts a month ago and didn't bother to do it until just recently. I was thinking that oh well, might as well do it since I have the parts. After driving around, I can say that this mod made more difference than the K&N filter I put in a few weeks ago. I can honestly say that I felt no difference with the K&N filter.

 

No offense taken. I did the mod to prove everyone wrong! I didn't believe that it could make a difference, but didn't have anything to back up my thoughts. I wanted to install the kit so I would have real world experiance that it didn't do anything. I was truly surprised when it did, and I am now a convert.

 

This is my viewpoint as well. I don't really see how a digital computer ECU can perform better with a cleaner power source (what a grounding kit is supposed to do). Right now, I am typing this message on a laptop. If this laptop's power supply starts acting flaky, it won't start making erroneous calculations and adding my columns wrong in Excel, it will keep working until it shuts down or fries its little electronic brains out. I don't see how a digital system's performance can deteriorate proggressively from poor power - it seems that it either works or it doesn't at all.

Maybe if someone gave me a better rationale for why a grounding kit would work (other than better ground = better performance of the ECU - which seems to be what the manufacturers of these kits are providing as explanation) I would go for it. Right now it's hard not to call it placebo effect. But I am open to argument.

Jason

 

Digital signals is a series of 1's (5volts) and 0's (0volts). If you have a poor ground it's called a float and is neither 5 or 0.

Your laptop computer has error correction in it. It knows what it's supposed to see and recalculates data accordingly. The time it takes to recalculate this data is infinitesimal and not noticeable because we're talking nanoseconds.

A typical automobile ECU accepts all inputs and attempts to adjust the engine to the inputs it's getting. Some of these signals could be floats. Because of the inherent noise (alternator/stereo/wiper motors/coil/etc.) in cars the only way to insure a better signal is to either rewire your entire car with shielded wires or to give it a better ground. Since rewiring is not cost effective, giving the electronic components a better ground becomes the better option.

Basically it's the same thing as when you have a poor ground in your car stereo and you get that obnoxious whistling sound in your speakers. (I'm assuming most everyone has heard that before) Your ECU doesn't know how to interpret that whistling as data and it results in poor performance.

 

I don't think technical data or a "rational answer" would sway you. You still won't believe in this grounding kit. You would have to try to believe; just as I have. If it doesn't work, you can always take it off and sell it to someone.

For me, I don't really care how it makes it smoother. I believe what I can feel.

 

I guess I'm still on the skeptics side as well - although the kits do look great. I'm figuring that, if they work that great, Nissan would be slapping them on every car, as would every other manufacturer. Isn't everything grounded to the same point (electrically) anyway?

P.S. - Not knocking anyone who is a "believer".

WayneTN

 

I installed a kit in my Z and I know it made the engine run smoother. It made it much easier to start from the line in 1st from a light by matching power to clutch without any stumble. I was so impressed that I had one made for my Chevy K1500HD truck. When I cracked the hood to take measurements, I noticed that Chevrolet had 2 wires leaving the ground of the battery and heading in opposite directions. I also noticed basic strap type cables connecting portions of the engine well, engine and drivetrain.
Chevrolet already had a better grounding installation, stock, than my Z had. I installed a kit anyway, but don't know that it is making that much difference in the truck, because of it's stock setup.

 

Grounding kit theory has been discussed in excruciating detail in other threads. The fact remains that grounds must travel through the entire engine, through multiple types of metal alloys with electrical components hooked up to them all with their own differences in potential. Shortcutting the path to reach a ground and ensuring they are all attached to the same ground point can only help, it certainly won't hurt. The size of wires used is excessive in these kits, but that's more for looks than anything else.

With all that being said, I installed a grounding kit on mine and noticed a difference at idle, but didn't really notice anything at higher RPM's. To be fair I'd only driven the car about 150 miles by that point and I didn't know the characteristics of the engine all that well.

 

it is all about resistance, if u have an electric motor with high resistance wires it will not be able to perform to its capabilities....same with a car...when something disrupts the electrical connection it will become rough, the fuel injectors wont be as smoothe

you want the voltage to be equal as possible that is why they have "matched batteries" which have the same output voltage

this is why people solder wires

 

I know this doesn't really matter Stop7alkin, but in an electric motor it's not the resistance in the wires, it's the resistance created by heat and inductance. Like I said, not important and doesn't have any real importance to this thread, but I felt compelled to respond.