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The efficiency figure of 124 MPGe combined makes it the most efficient vehicle in the US by a fairly big margin but the 81 mile EPA range rating is a bit disappointing.

The fuel tank for the REx has been reduced in size for the US market and it seems that this is due to the lower range rating. They need the range available when using the REx to be no larger than the battery range so the tank has been 'tweaked' to ensure this.

This ties in with the stats that I've been keeping on my longer trip because I get about 25% more range with the REx than when only using the battery and the US tank has been reduced in volume by 21%.
 

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This fuel tank thing is a 'myth'. The European and NA parts are the same. See realoem.com. Same part numbers.

The tank is 9 litres which is 1.9 Imp. as in the English version of the user handbook.

This just so happens to be 2.4 US gallons which was previously on the BMW US web site.

When the US guys were trained they were shown a slide that showed the tank capacity as 1.9 with no units attached and therefore assumed they are being "stiffed" by BMW as a result of EPA restrictions.


No one is prepared to admit they have made yet another units mistake similar to NASA. ;-)

And unless I am mistaken the 81 range is nothing to do with tank size?
 

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The efficiency figure of 124 MPGe combined makes it the most efficient vehicle in the US by a fairly big margin but the 81 mile EPA range rating is a bit disappointing.

The fuel tank for the REx has been reduced in size for the US market and it seems that this is due to the lower range rating. They need the range available when using the REx to be no larger than the battery range so the tank has been 'tweaked' to ensure this.

This ties in with the stats that I've been keeping on my longer trip because I get about 25% more range with the REx than when only using the battery and the US tank has been reduced in volume by 21%.
Fuel tank size unchanged from Europe.
 

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This fuel tank thing is a 'myth'. The European and NA parts are the same. See realoem.com. Same part numbers.

The tank is 9 litres which is 1.9 Imp. as in the English version of the user handbook.

This just so happens to be 2.4 US gallons which was previously on the BMW US web site.

When the US guys were trained they were shown a slide that showed the tank capacity as 1.9 with no units attached and therefore assumed they are being "stiffed" by BMW as a result of EPA restrictions.


No one is prepared to admit they have made yet another units mistake similar to NASA. ;-)

And unless I am mistaken the 81 range is nothing to do with tank size?
Hi Gonville,

I see your prolific green text is appearing here now too :)

The realoem site has been around for months so why do you think the data shown there is more up to date than the BMW presentation given to the US dealership personnel a couple of weeks ago ? The slide was shown to specifically explain a change in fuel tank volume so I remain unconvinced about the conversion error story, not that I'm particularly bothered either way seeing as it doesn't impact on us.

The 81 EPA range is connected to tank size because BMW want the REx to be qualified in the US as a BEVx (for a variety of reasons) and one of the stipulations of that is that the petrol range must be less than the battery range. My REx gets about 25 more miles in petrol range than it does when purely on the battery so the smaller tank would fix that for the US market.

I'm sure you've already see this link but for anyone else interested, this is Tom's take on it

http://bmwi3.blogspot.co.uk/2014/04/more-range-extender-details-uncovered.html
 

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Hi Gonville,

I see your prolific green text is appearing here now too :)
I quite like the green ;-)

I have seen the BMW presentation and I think the key thing is that it does not contain a "unit".

The other key factor is that the User manual says explicitly "1.9 imp.".

The realoem site is also updated with parts from last year right through to January this year.

I think Tom's blog was posted in a number of places where the comments about 9l = 2.4US have been made by a number of people - not just in green ink!
 

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The BMW presentation is shown on Tom's blog post. The conversion explanation is even murkier when you realise that 1.9 imperial gallons does not equate to 2.4 US gallons (it's actually 2.3) but I guess that comes from the UK handbook classifying 9 litres as 1.9 gallons which is also incorrect.

Anyway, I've already wasted too many brain cells thinking about an unimportant subject, I was just giving a summary to Paul with the OP link being dead, lol.

Have you taken delivery of your i3 yet ?
 

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I think I have at least another n months to wait where n is the same number as it was when I placed my order. Leather is bad news apparently.

I was aware of the inaccuracies of the units conversions......there was a post in reply to Toms blogs which had the exact numbers including the rounding up and down to single digits that BMW seem to prefer. These posts seem to have been removed. I guess that's another conspiracy theory.

It's just annoying that a fine engineering firm is being presented as pulling a fast one on North American clients.
 

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Tom's remarks get mentioned in some serious analysis of a number of issues by NIKKI GORDON-BLOOMFIELD here:-

http://transportevolved.com/2014/04...ex-smaller-gas-tank-range-hold-limited-speed/

In Europe, the i3 REx’s fuel tank is 9 litres — 1.98 gallons imperial or around 2.37 U.S. gallons. But, says Moloughney, U.S. dealers who have been to the training are quoting a fuel capacity of 1.9 U.S. gallons. That’s an equivalent drop of 21 percent, or in other words, a range-extension of about 50 miles per tank instead of the 80 miles or so offered by European models.
But the article goes on to conclude, after reference to a bladder model, the following:-

The second potential reason — which is more of a confusion than anything else — could be related to nothing more than a simple misunderstanding.

You see, there’s a difference between UK (Imperial) and U.S. gallons. In its original specification, the 9-litre BMW i3 REx gas tank equates to 1.98 UK gallons, or 2.4 U.S. gallons. It’s conceivable that someone at BMW mistakenly converted the gas tank size of the U.S. market car by using UK rather than U.S. gallons.
I think that is well presented but who knows we could all be wrong.

I await September/October/November with anticipation.;)

 

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but who knows we could all be wrong.
Agreed :) I don't think TE's take on the conversion 'theory' adds anything new, they just regurgitated what was first suggested in the i3 facebook group. As for the bladder, the i3's fuel tank is pressurised (you have to press a button to vent it before you can unlock the cap).

We should find out soon enough seeing as the first US customers have now started taking deliveries of their cars. It wouldn't surprise me if it was BMW getting their communication wrong as they made a few mistakes here in the UK when the first sales information came out last summer.

I await September/October/November with anticipation.;)
Eeep, not for a while then. Hope you are luckier than that and it arrives sooner.
 
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