The 370Z Weight Reduction Thread

[wstar]

Wow, that thing is tiny. No spark issues? TBH, I don't really know the low-level electrical details of how engine ignition systems work, but I was under the impression that basically an engine can't generally run very well on its alternator alone; that the required juice to give a full-power spark comes from the battery (in rapid intermittent bursts as the plug fires), and the relatively-constant output of the alternator is topping off the battery between those bursts. Which is why really tiny batteries always worry me a little, re: potential to lose some of your full spark amperage. I could be way off-base, though!

[ChipsWithDips]

The battery uses LiFePo4(Lithium Iron Phosphate) chemistry, which has a tremendous power to weight ratio. Its the same battery technology as used in the worlds fastest electric drag motorcycle killacycle. I haven't cracked open the case(its thermo sealed) to check if they are actually A123 cells(generally considered the best LiFePo4 cells), but it does the job quite well.

It is not relying on alternator alone with a small battery. The battery will be slightly discharged after cranking, but will get topped off quickly by the alternator. Voltage gauge reads 14.4 while engine is running.

At this size it doesn't have nearly the capacity (amp hours) of a full size lead acid, but short bursts is what it excels at. The only risk with lower capacity is that you could drain it fairly quickly if you aren't careful. Just don't run electrical without the engine on.

[ChipsWithDips]

Those dimensions are not accurate, its closer to 4-5" cube.

[synolimit]

Originally Posted by ChipsWithDips

Those dimensions are not accurate, its closer to 4-5" cube.

Ahh much better.

[wstar]

Hell at that size and weight, I might consider moving the battery back up to the battery box instead of the trunk. The cabling to the trunk probably outweighs the battery itself

[theDreamer]

Originally Posted by wstar

Hell at that size and weight, I might consider moving the battery back up to the battery box instead of the trunk. The cabling to the trunk probably outweighs the battery itself

I just started talking to Wstar about moving mine but at how light the batteries are getting & efficient, may as well keep it up front.

[dirTy_shoeZ]

Originally Posted by theDreamer

I just started talking to Wstar about moving mine but at how light the batteries are getting & efficient, may as well keep it up front.

ive seen race cars make a box under the headlight, looks really nice, and is out of the way, also not using to much more battery cable. just a thought

[synolimit]

Originally Posted by wstar

Hell at that size and weight, I might consider moving the battery back up to the battery box instead of the trunk. The cabling to the trunk probably outweighs the battery itself

First thing I saw when you guys moved the batteries was the cable. Thought to myself, kinda defeats the purpose. Then I saw some installed in the middle of the trunk which again I thought, driver weighs 100+ lbs, 30 lbs oem battery was on passenger side, now 15 lbs battery is in the middle of the trunk, again defeats the purpose. If anything the battery should be under the passenger seat.

[wstar]

You're a very negative nancy :P

The cables aren't much compared to the battery weight shift, and more importantly the cable weight is distributed out fairly evenly. Shifting weight from front to rear is always good (unless you actually manage to cross the 50/50 mark). Shifting weight towards the center of the car from where it originally was further out in any direction is always good (driver-vs-passenger can always be corrected later with corner balancing).

Not everything on these jobs may be perfectly ideal, but they still do a lot of good. The placement didn't "defeat the purpose".

[synolimit]

Originally Posted by wstar

You're a very negative nancy :P

The cables aren't much compared to the battery weight shift, and more importantly the cable weight is distributed out fairly evenly. Shifting weight from front to rear is always good (unless you actually manage to cross the 50/50 mark). Shifting weight towards the center of the car from where it originally was further out in any direction is always good (driver-vs-passenger can always be corrected later with corner balancing).

Not everything on these jobs may be perfectly ideal, but they still do a lot of good. The placement didn't "defeat the purpose".

Lol no just stating what I see. Hell I have no idea where all the weight should be. I want to get a corner balance done. So far I've removed the stock exhaust, everything in the trunk, windshield washer bottle full of fluid, some engine hoses and brackets and covers etc so I might be killing my cars weight distribution. Adding a battery to it, TS over cats etc, its all going to effect the car some how. Guess ill find out when I'm done.

[wstar]

The rear is much easier to remove excess weight from than the front for sure, which is unfortunately backwards. It all changes when you stop caring about it being a street car. Most of the easy weight removal in the front is stuff you'd never do on a daily-driver (forward interior plastics, airbags, air conditioner, radio, etc).

[synolimit]

After my CBE I went and got weighed again. With everything I've taken out and a full tank of gas I'm at 3280. So 81 lbs to date. Good news for me when I go to the strip with 1/4 of gas and passenger seat removed ill be at 3152

I still have a CAI to build, lighter battery, test pipes, wheels and tires, and rotors. I don't think ill break 3000 it will be close.

-34.3 lbs in wheels and tires
-19 lbs battery
-28.4 lbs rotors
Test pipes???
CAI???

[ZoroItaliano]

Is it safe to say that the real gains of an exhaust upgrade lies in weight savings? If this is the case, I would think that just replacing the stock mufflers would be an upgrade it itself. I guess what I'm asking is out of all sections of the exhaust, which section is worth changing to consider it an "upgrade"....

[wstar]

The engine responds well to exhaust and intake mods in general, thanks to VVEL and the self-tuning it can do with the MAF + Lamba inputs, so I wouldn't say the main purpose of an exhaust upgrade is weight savings, but weight savings can be had there. Since most of the weight is low and to the rear though, it's not the ideal location, but every pound counts in the end

[wstar]

Also, I can report now that the electric tape and plastic conduit material in the car's wiring harnesses adds up to approximately 443 lbs of messy, sticky, crap. At least, it feels like that as you pull it all apart