Hey all,

I'm looking for the weight specs on my sedan, a 2003.5. All I have found so far is the weight distribution, 52% front and 48% rear. Nice. But I also need to know the sprung weight - total and at each wheel. I think if I have these figures it will keep me busy for a while. Thanks for all your help!

 

If I recall the 03 and 04 (w/ leather) weigh 3369lbs. I could weigh one of my stock sport wheels for you one of these days but I would guess ~45-55lbs each so take 180-220 off the 3369. Not sure if the 3369 includes fluids, I would guess not.

 

curb weight includes fluids and driver (150 lb driver i believe)

 

Hey thanks! Is that 45-55 lbs the wheel including the tire or not? If not, man those things are heavy!

 

that should be with the tire included our wheels are heavy..but not that heavy.

 

Yeah, I'm going to check it out today, I'll post up info soon.

 

Yes that is with the tires. They are ~25-28 lbs without the tires. (I think)

 

Any ideas on the locations of

1. Front roll center
2. Height of center of gravity?

 

No clue...

What, may I ask are you trying to determine?

 

a flying sedan?

 

Lol!!!

Being an Aerospace engineer that last email made me think the same thing.

 

Are you possibly inquiring because you plan on serious track duty for your sedan?

 

Bingo. That would be my ultimate goal someday. Or maybe I'm just bored. I've got some spring options to play with and I got into a small book called "Chassis Engineering" about tuning for high performance suspension. Just at a glance, the G looks to be set up great, I'm just curious to see the effects of lowering it and whatnot. Form has always got to follow function in my eye, although a lowered car always does look nice.

So, yeah, I'm just wasting time finding info. Perhaps suspension design could be my senior project (fingers crossed) before I get my BS in ME. And no, no flying cars. The CG and Roll center could be affected if I drop it too much, in a negative way. I have a set of 350Z revised shocks and springs and a set of Hotchkis springs awaiting install. So far I plan to put the Hotchkis spring up front and Z spring in the rear. So unlike the common Z front/coupe rear, I'll have an even lower front and just a low rear, if that makes sense. Or I could run the Hotchkis at all four but that may be too low for the rear (a possible 1.8" drop).

 

Don't forget about the effects of upgrading sway bars when dealing with body roll forces and roll centers. Also, be careful not to drop the front too much lower than the rear, or you could affect weight transfer. One thing I've noticed from tracking my g is that with the brakes having such good initial bite, it's easy to induce an unanticipated amount of brake dive which causes the front end to push quite a bit (and brakes to heat up), and trying to correct it with the throttle is tricky because now the back end is light. With the car already raked on lower front springs, you could be in a brake dive stance while static, which may only exacerbate the weight transfer from rear to front when you do hit the brakes.
Of course, most of this usually goes away after the first few laps, as you get the feel of the car and the track and find the best line.

 

^ Cool. Thanks for the tip. I don't imagine it to be too bad on the brake dive side, as the front will be a little over a half inch lower than rear - but that only gets rid of the cosmetic larger front wheel gap. The Hotchkis springs are also a little tougher - 340 lbs/in - as opposed to the Z 314 lbs/in springs. I thought the higher spring rate up front could better offset the obscenely high (IMO) rate of the stock Z springs at 427. I may try doing the Hotchkis all the way around just to see how it feels and if my car will make it around the city that low. Otherwise it will be all Z springs and a set of Hotchkis springs for sale...