Weight savings?

[Calichase]

So I am curious about the weight of a z4m coupe.
I have found the stock weight to be 1485kg or roughly 3273 lbs. But I do not know if this is accurate or if this is with or without a driver or with a full tank of gas. So first I should ask, does anyone have an accurate weight of a z4m coupe with a full tank of gas and a driver. I weigh 165 so we could modify the result to get a proper weight for myself.

If the gas tank holds 55 liters and a liter of gas weighs .76kg or 1.675 lbs= 92.125lbs of gas alone for a full tank!

My other question is if it is possible to get a m coupe under 3000lbs with a 165lbs driver and a full tank of gas? My guess is no way! But how lightweight could I get with the following
Racing bucket seats
Lightweight wheels/tires
Removal of unnecessary items
Lightweight battery
lightweight muffler->rpi

Assume a roll cage and other safety equipment isn't a part of the situation.

I don't think this can be done without going extreme and changing the body to carbon fiber and replacing the glass with plexiglass and removing the passenger seat.

Something that I was thinking about... I believe the new alms BMW z4m gte weighs in around 2700lbs. I don't know if this is with a full tank and driver but the car is also a true racecar built on a different chassis,e89, with a v8. Probably not much of comparison.

I'm sure there are factors that I'm forgetting, such as the cars options Which might alter things.

Thanks in advance to all the knowledgable track junkies!

[seank]

I don't know.

Yes, of course but not as a daily driver. You can probably save 160 lbs with 1 light weight seat and no passenger seat. If you got rid of the stock ecu, you can remove at least 75 lbs just in misc wires that you don't need.

Plexiglass and carbon fiber isn't extreme, unless its your daily driver.

Btw, no race cars run a full tank, unless its an endurance race.

[Calichase]

Originally Posted by seank

I don't know.

Yes, of course but not as a daily driver. You can probably save 160 lbs with 1 light weight seat and no passenger seat. If you got rid of the stock ecu, you can remove at least 75 lbs just in misc wires that you don't need.

Plexiglass and carbon fiber isn't extreme, unless its your daily driver.

Btw, no race cars run a full tank, unless its an endurance race.

All very good points

[beta]

Search the forum for crfine88 threads, here's one to get you started.

Seats are about 60lbs each so with only one racing seat you can save about 100 lbs. Battery you can shave off about 40 lbs. Wheels maybe 20 lbs or so. 45 lbs if you remove the radio/nav. Lexan maybe 60lbs?

[Kgolf31]

I got my car weighed in at 3231 with half a tank of gas w/out me in it.

If you really wanted to strip weight, you can remove the windshield wiper fluid container, as well as just make an exhaust that dumps down at the ground directly after the headers. But of course I think we're getting to extremes here.

160lbs isn't doable for seats. You're talking at ~60lbs in each seat. So if you completely remove one, you're looking at 60lbs in savings. If you remove the driver and replace with a race seat, you're still factoring in hardware to mount the seat, and is around 20-25 or so lbs.

[seank]

Originally Posted by Kgolf31

I got my car weighed in at 3231 with half a tank of gas w/out me in it.

If you really wanted to strip weight, you can remove the windshield wiper fluid container, as well as just make an exhaust that dumps down at the ground directly after the headers. But of course I think we're getting to extremes here.

160lbs isn't doable for seats. You're talking at ~60lbs in each seat. So if you completely remove one, you're looking at 60lbs in savings. If you remove the driver and replace with a race seat, you're still factoring in hardware to mount the seat, and is around 20-25 or so lbs.

I haven't weighed the seats. It was guesstimate on what they felt like. Remove the two seats and add one 20lb fixed back seat and you have saved 100lbs. Aluminum seat mounts and hardware is maybe 5 lbs. http://cdn.nexternal.com/vacmotors/i...IK-E30-S-L.JPG

Most of the weight is in the electronics, wiring, factory exhaust and airbags which is probably getting extreme unless it's a track car.

[The HACK]

When I had my car corner balanced, it had 3/4 tank full of gas, and they corner balanced it with a 225 lbs weight in the driver's seat and 180 lbs weight in the passenger seat (the most typical configuration the car would be ran on the track). Total weight came to 3,602 lbs. So that means with a full tank of gas and no driver, the car likely weighed just about 3,250 lbs.

I spoke with a friend who built an E90 M3 into H-Prepared rules, and he said they managed to strip a 3,800 lbs E90 M3 (without driver) down to 3,400 lbs with driver. These newer chassis are harder and harder to "strip" a lot of weight from. I recall another friend who built an E36 M3, 3,200 lbs without driver stock, down to about 2,600 lbs with driver for I-Prepared rule having to actually add ballast to maintain weight eligibility.

But both of those cars are sedans with a lot more material to remove, like back seat and rear passenger trims. On the MZ4 Coupe? I think if the car were to be prepared to H-Prep rules (before weight penalties applied), you can probably safely expect the car to weigh around 2,900 lbs with driver (so maybe about 2,700 lbs empty).

To see any more significant weight gains from that, you'll have to go to composite panels which would bump you into Mod class.

[ZStig]

I'm at 3187lbs with


+ supercharger kit with intercooler
- 16.5lbs Volk TE-37
- euro catless headers
- 11.5lbs battery
- 8.5lbs plastic roadster trunk tray
quarter tank of gas, no driver

[Calichase]

Originally Posted by ZStig

I'm at 3187lbs with


+ supercharger kit with intercooler
- 16.5lbs Volk TE-37
- euro catless headers
- 11.5lbs battery
- 8.5lbs plastic roadster trunk tray
quarter tank of gas, no driver

Yes but you are also a roadster. And just going off topic here. But how much did the s/c add?

[ZStig]

Originally Posted by Calichase

Yes but you are also a roadster. And just going off topic here. But how much did the s/c add?

I wish I measured. The intake manifold is replaced, so its not all positive weight gain. I'd say about 40-60lbs max

[Calichase]

Originally Posted by ZStig

I wish I measured. The intake manifold is replaced, so its not all positive weight gain. I'd say about 40-60lbs max

That really throws off the nearly perfect 50-50 front/rear ratio the car has. It's hard to compensate for that amount of added weight in the front

[dre99gsx]

Z4M Coupe Weight ReductionI have a thread going with all the weights.

[pal]

My coupe weighed in at ~3275 lbs with almost a full tank and no driver. Weight was a bit rear biased (50.5% rear if I recall).

[ZStig]

Originally Posted by Calichase

That really throws off the nearly perfect 50-50 front/rear ratio the car has. It's hard to compensate for that amount of added weight in the front

I've compensated with Coilover suspension and an OEM engine brace. Then -1.5* camber with 265mm tires up front. That keeps the front turn-in nice and tight. Plus the catless headers are considered to be a front end weight loss