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E63 / E64 6 Series (2003 - 2013)
The E63/E64 BMW 6 Series builds on BMW's sporty heritage with aggressive lines and an incredible motor to back the design up. Available in coupe and convertible trims with a standard 4.8 liter engine producing 360 horsepower and 360 lb-ft of torque, the 6-series is a popular choice that exceeds expectations.

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  #1  
Old 01-16-2006, 08:36 PM
SmoothCruise SmoothCruise is offline
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em3: Another idea to lighten the 6er.

This is more a general question, but I figure I'd throw it out to evm3 who is on the quest for the lightest 6er ever.

If the seal on your tires can keep it in, why not fill your tires with helium? It's less than 1/10th the density of air, so the moment of inertia of your tire should be greatly diminished. Plus, helium is relatively cheap.

You could also fill your tire with hydrogen, but that could be dangerous.
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  #2  
Old 01-16-2006, 08:40 PM
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Nevervana Nevervana is offline
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Hell, fill it with plutonium.
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  #3  
Old 01-16-2006, 09:23 PM
Malibubimmer Malibubimmer is offline
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Quote:
Originally Posted by SmoothCruise
This is more a general question, but I figure I'd throw it out to evm3 who is on the quest for the lightest 6er ever.

If the seal on your tires can keep it in, why not fill your tires with helium? It's less than 1/10th the density of air, so the moment of inertia of your tire should be greatly diminished. Plus, helium is relatively cheap.

You could also fill your tire with hydrogen, but that could be dangerous.
The weight saving would be miniscule and helium, consisting of smaller molecules than atmospheric air (primarily oxygen and nitrogen), will leak out and leave the runflats flat.
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  #4  
Old 01-16-2006, 09:28 PM
SmoothCruise SmoothCruise is offline
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Quote:
Originally Posted by Malibubimmer
The weight saving would be miniscule and helium, consisting of smaller molecules than atmospheric air (primarily oxygen and nitrogen), will leak out and leave the runflats flat.

I bet you it's more than the weight savings on a CF front grill?!? And, plus when you factor in it's rotational inertia, it's probably better than a CF front grill, provided you can seal it.
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  #5  
Old 01-16-2006, 10:06 PM
Malibubimmer Malibubimmer is offline
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Originally Posted by SmoothCruise
I bet you it's more than the weight savings on a CF front grill?!? And, plus when you factor in it's rotational inertia, it's probably better than a CF front grill, provided you can seal it.
I don't know how much the CF front grille will save, but I suspect the weight savings of helium is no more than a fraction of an ounce per tire. The weight gain necessary to tighten the seals for each tire would probably be more than an ounce per tire. So, I don't think this is a very good idea.

While I haven't done a I suspect someone who was industrious enough could find the infortation about this on the Internet, since I don't think Nevervana is the first to come up with this idea.
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  #6  
Old 01-16-2006, 10:57 PM
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lawman800 lawman800 is offline
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I think spending an extra 5 minutes on the can before you drive would save you more weight than the helium tires and the CF grill combined.
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  #7  
Old 01-17-2006, 12:25 AM
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Nevervana Nevervana is offline
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Quote:
Originally Posted by Malibubimmer
I don't think Nevervana is the first to come up with this idea.
Wasn't my idea. My idea was Plutonium.

Lawman....
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  #8  
Old 01-17-2006, 06:22 AM
devin112 devin112 is offline
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Air is too heavy now? This is news to me.
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  #9  
Old 01-17-2006, 06:31 AM
SmoothCruise SmoothCruise is offline
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Quote:
Originally Posted by Malibubimmer
I don't know how much the CF front grille will save, but I suspect the weight savings of helium is no more than a fraction of an ounce per tire. The weight gain necessary to tighten the seals for each tire would probably be more than an ounce per tire. So, I don't think this is a very good idea.

While I haven't done a I suspect someone who was industrious enough could find the infortation about this on the Internet, since I don't think Nevervana is the first to come up with this idea.

Just eye-balling it, it seems more effective. I think evm3 would save more weight than swapping his stock grills for CF grills. Here's some estimates.

Assume about 1cm thickness for air pocket in a 20" tire that's 10" wide.
So in cm, the tire is about 50 radius by 25 cm wide. So, the air pocket is roughly
1cm thick * 50Pi in length * 10 in width = 1550 cc.

Now air is about 1.27 mg/cc, so that's 1968.5 mg of air in a tire, at 1 bar, about 2g.
But, the 6er has about 33pounds of pressure, or roughly 2 bars, so it's really about 3.8g of air in a 6er tire. Now, multiply that by 4, and you get about 15g of air in your tire.

Since helium has a density less than 1/10th that of air, he'll have less than 1.5 grams of helium in his tires, saving roughly 14g of weight.

Now, don't forget that in calculating moment of inertia, which is more important than weight when it comes to tires, mass is multiplied by a factor which is a function of the square of the radius. So, take the weight savings and multiply that by at least 50 squared which is 2500.

So just think, if evm3 thought his car would accelerate faster with CF grill. His car should accelerate even more so with helium filled tires.

Last edited by SmoothCruise; 01-17-2006 at 06:51 AM.
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  #10  
Old 01-17-2006, 06:38 AM
SmoothCruise SmoothCruise is offline
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Ofcourse, what's true for bicycle wheels is also true of car wheels.



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  #11  
Old 01-17-2006, 07:18 AM
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u guy's.
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  #12  
Old 01-17-2006, 07:55 AM
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Here's another one, how about driving with only 1/2 tank? A full tank weighs too much. Every racer knows at the end of the race, the lower fuel load does increase performance somewhat. The 6 has 18 gallons so save 9 gallons of weight!

Anyone here know how much 1 gallon of gas weighs?
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  #13  
Old 01-17-2006, 08:30 AM
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chuck92103 chuck92103 is offline
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Quote:
Originally Posted by lawman800
Here's another one, how about driving with only 1/2 tank? A full tank weighs too much. Every racer knows at the end of the race, the lower fuel load does increase performance somewhat. The 6 has 18 gallons so save 9 gallons of weight!

Anyone here know how much 1 gallon of gas weighs?
1 gallon of water equals 8.33 lbs.
1 gallon of gasoline equals 5.8 to 6.5 lbs.
1 gallon of ethanol equals 6.59 lbs.

If you are retaining water on race day, I would postpone.
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  #14  
Old 01-17-2006, 08:49 AM
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gbelton gbelton is offline
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Already being done...

Smooth,

You are a very astute and well read guy. I say this because you not only mathematically described/proved the helium would be better for the driver but in California this is already being tested. I do believe this testing is limited to a certain population but you have hit the nail right on the head when it comes to people thinking about lighter, more efficient ways to run their cars. Burning less gas seems to be there motivation versus what you describe.


In the end, those who race their 6er and need the extra weight reduction I would take everything each poster stated with the exception of Plutonium, and Hydrogen. Kaah-Boom! No thanks!

Good reading anyway and I am sure everyone can appreciate the thought.

Check this out from Google: http://www.parker.com/ead/cm1.asp?cmid=842

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  #15  
Old 01-17-2006, 05:15 PM
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Wow, if 1 gallon of gas is roughly 6 pounds, then 18 pounds is 108 pounds so if you can cut any of that out, like at least 1/2 the capacity, then you can save 54 pounds. You can't save that much weight no matter how long you sit on the can!
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  #16  
Old 01-17-2006, 05:26 PM
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BruceWayne BruceWayne is offline
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Thats the reason I drive on empty all the time.
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  #17  
Old 01-17-2006, 07:13 PM
MysticBlue MysticBlue is offline
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Quote:
Originally Posted by SmoothCruise

Now, don't forget that in calculating moment of inertia, which is more important than weight when it comes to tires, mass is multiplied by a factor which is a function of the square of the radius. So, take the weight savings and multiply that by at least 50 squared which is 2500.
You can only make that argument concerning rotational enertia if the material is a solid. The air is not going to begin rotating as a solid as the tire rotates.
You're talking about 1/2 an oz. here.
Some ideas that would make more of a difference:
Get a haircut.
Go commando (no underwear).
Take one floor mat out.
Vacuum the interior.
Run 5 1/2 qts of oil instead of 6.
If you wear over the calf socks, change to ankle socks.
Shorter shoelaces.
Cut those spare buttons off the bottom of your shirt. You don't know how to sew anyway.
Always leave your change in the little change bowl on the counter, never carry any in the car.
Hey, was it your idea to leave out the dipstick to save half a pound and a dollar and a half of material? Genius.
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Last edited by MysticBlue; 01-17-2006 at 07:21 PM.
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  #18  
Old 01-17-2006, 07:18 PM
Malibubimmer Malibubimmer is offline
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Originally Posted by lawman800
Wow, if 1 gallon of gas is roughly 6 pounds, then 18 pounds is 108 pounds so if you can cut any of that out, like at least 1/2 the capacity, then you can save 54 pounds. You can't save that much weight no matter how long you sit on the can!
Unless you're 19 year old Lindsay Lohan (who drives a 604 HP SL65).
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  #19  
Old 01-18-2006, 12:39 AM
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Lindsay also turned that SL65 into scrap right quick! Sometimes losing too much weight can give you too much acceleration, I guess.
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  #20  
Old 01-18-2006, 02:12 PM
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If you really want to save some weight, get rid of the stuff you don't need. As suggested, floor mats, trunk liner , battery cover windshield washer fluid, wiper blades and arms. And while you are add it, replace your seat with CF seats. I've got to believe the stock seats themselves weigh around 100lbs ea. Hell, evm3 could have a complete CF seat instead of just the back of it.
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  #21  
Old 01-19-2006, 10:16 AM
devin112 devin112 is offline
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LOL, nice one MysticBlue! lol

That gave me a good laugh.
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  #22  
Old 01-19-2006, 10:19 AM
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lawman800 lawman800 is offline
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Quote:
Originally Posted by Jp_Austin
If you really want to save some weight, get rid of the stuff you don't need. As suggested, floor mats, trunk liner , battery cover windshield washer fluid, wiper blades and arms. And while you are add it, replace your seat with CF seats. I've got to believe the stock seats themselves weigh around 100lbs ea. Hell, evm3 could have a complete CF seat instead of just the back of it.
The CF backing, unless it replaces the assembly, would be just another tack-on accessory that overlays the stock component, thereby adding bulk and weight instead. Some on Fleabay has been selling those backings which just clamp on the stock seats.

I still say spend some quality time on the can. Always worked for me. Although sometimes it turns your morning ride into a mid-brunch ride....
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