Bigger Rex fuel tank

[spiraleyes]

I keep seeing people talk about how either the Rex tank size is smaller in the US, or how it isn't due to the confusion between UK and US gallons. I think it's important to point out that the BMW global site claims an i3 Rex can reach up to 300km range(186.411 miles). The BMW USA builder page claims a US i3 Rex can reach 185 miles of range. So is the USA site wrong, or is the Rex tank size actually the same in the US version as it is in Europe?

 

[dvottero]

To your point spiraleyes, we don't actually have any cold hard facts supporting that the US got a differently sized fuel tank.

Show me two different parts on a table, with two different part numbers and I'll believe the conjecture -- but right now there isn't enough evidence to support this claim. It's all circumstantial.

It's plausible that the tank capacity didn't change, but just the published size did. And/or how much the car is available to use through software.

There has been precedent for other automakers to address these issues with software and/or published figures. The SMART ForTwo's gas tank is 10 gallons, but the published capacity is 8.7 gallons. The remaining is "reserve."

 

[MarkN]

Can you identify which vehicles are "gas guzzlers"? (besides the M5 which is still a V8 but only 232g CO2. combined MPG 28.5

How about the X5 and X6 with US EPA combined ratings ranging from 14 to 19 MPG for gasoline engines? The X5, with 39,818 sold, was BMW's third-best selling model in the US in 2013, after the 3 series (119,521) and 5 series (56,863).

 

[stumbledotcom]

Show me two different parts on a table, with two different part numbers and I'll believe the conjecture -- but right now there isn't enough evidence to support this claim. It's all circumstantial.

Thank you. Completely rationale. It seems pretty logical to me that California Air Resources Board rules drove the REx design worldwide. BMW's goal was to have both versions of the i3 qualify for Zero Emission Vehicle Credits.

http://www.arb.ca.gov/msprog/zevprog/zevcredits/2012zevcredits.htm

The fact that the i3 REx is the first vehicle with a gas engine to be classified as electric by CARB is a significant accomplishment.

http://www.greencarreports.com/news...el-gets-full-2500-ca-rebate-for-electric-cars

And while I know that people from other places laugh at us, ZEV credits are already a huge part of the car business here and will only get bigger. BusinessWeek reports that Tesla sold $119 million of credits during the first half of 2013 alone.

http://www.businessweek.com/news/20...alifornia-green-car-credit-sales-in-past-year

The accumulation of ZEV credits also explains why California dealers are making i3 deliveries while waiting lists exist in other parts of the country and world. Sorry UK friends, in particular.

 

[Gonville]

Can you identify which vehicles are "gas guzzlers"? (besides the M5 which is still a V8 but only 232g CO2. combined MPG 28.5

How about the X5 and X6 with US EPA combined ratings ranging from 14 to 19 MPG for gasoline engines? The X5, with 39,818 sold, was BMW's third-best selling model in the US in 2013, after the 3 series (119,521) and 5 series (56,863).

That's true. I was focusing on the 5 series most powerful. So 119,521 and 56,863 are all in the non guzzling range? Being all better than the M5. So 18% of those sales could be considered as potential gas guzzlers based on choice of engine. More than 82% of those sales are better than the GM "average".

So on the X5 which do have some poor figures if you choose a petrol model. So how many of the 39,818 are gasoline? In the UK it's a minority due to the CO2 tax.

What's the equivalent GM model to the X5? How does that compare?

 

[Gonville]

true we forgot the 750iL. That is pretty bad.

But on the X5 equivalent SUV I think the other makers need to step up their game...






http://www.fool.com/investing/gener...lers-with-the-worst-combined-fuel-econom.aspx

 

[stumbledotcom]

That's true. I was focusing on the 5 series most powerful. So 119,521 and 56,863 are all in the non guzzling range? Being all better than the M5. So 18% of those sales could be considered as potential gas guzzlers based on choice of engine. More than 82% of those sales are better than the GM "average".

The CARB credit system applies to each manufacturer's total portfolio not just a brand. That means Rolls Royce and Mini fall under the BMW umbrella. I would guess someone in Munich is looking at it as the more i3s sold in California, the more Rolls Royce Phantoms the BMW Group can sell. The total portfolio view also explains why VW, a generally eco-friendly brand, is actually a net purchaser of credits. VW has to offset not only its Touareg sales but Audi, Bentley, Bugatti, Lamborghini, and Porsche.

 

[pdurham]

All the back and forth about the size of the tank and whether the U.S. tank really is smaller retraces the steps of my research and back-and-forth thinking. At one point, I fully believed that all the confusion must surely be the result of a mix-up between U.S. and Imperial gallons. It was so difficult to get clear reliable information on this subject that I even discussed with the salesman that if we couldn't otherwise verify the size of the tank, before taking delivery, I would ride with their service technician to a gas station when he preps the car for delivery and watch as he fills the REx tank!

But according to the salesman, the U.S. owner's manual for the i3 (same book for both the i3 BEV and i3 REx), says the tank capacity in the REx is 1.9 gallons. (It's my understanding that the tank is actually measured in liters, and is 7 liters for U.S. models and 9 liters for Euro models. We round that to 1.9 and 2.4 U.S. gallons, though the conversion from 7 liters actually equals 1.85 gallons for example.) The best, really, the only, theory I've heard is that the smaller tank was installed to qualify the car as BEVx under CARB regulations.

We live in Arizona, which is not a CARB state. (It was a few years ago, but not now.) It would be great if BMW would sell a non-CARB version of the car with a larger tank. HEAR THAT, BMW?

Also, a friend now on a trip to Belgium says he'll stop into a BMW dealer there and ask if he can order and buy the tank (the Euro 9-liter version of course) from their parts department. He's not planning to actually buy it; just doing some research to find out if he could. When I find out whether the tank is available and, if so, what the cost is, I'll consider next steps. I suppose I could take the Euro tank to my BMW dealer and ask them to put an i3 REx up on a hoist and, without actually doing it, tell me whether the Euro tank would fit. I'm pretty sure the dealer wouldn't be willing to do the installation, but I should be able to find a friendly mechanic. Of course, I'd love to find out that someone else has successfully done it first . . . .

I think we'll end up with an i3 REx some day. We just needed some time to get more and better information to sort this whole matter out.

 

[Gonville]

I think Tom is going to update us on how many litres he is topping up. That should settle it once and fit all.

 

[jadnashuanh]

The US BMW service training sessions say 1.9g. The US website says 1.9g. Until just before actual US release, it said 2.4g, then they changed it.

My guess is that if you could get someone to order a larger tank for you, it would probably fit, but who knows what other things may also be involved (could be nothing, could be a different gas line either to the tank or from it to the motor, or a different bracket, or a different filler door, nozzle, or maybe multiple things).

 

[pdurham]

Another excellent comment, jadnashuanh: "The US BMW service training sessions say 1.9g. The US website says 1.9g. Until just before actual US release, it said 2.4g, then they changed it. My guess is that if you could get someone to order a larger tank for you, it would probably fit, but who knows what other things may also be involved (could be nothing, could be a different gas line either to the tank or from it to the motor, or a different bracket, or a different filler door, nozzle, or maybe multiple things)."

First, it's news to me that the U.S. website said 2.4 gallons until just before actual U.S. release, when they changed it to 1.9. I had been seeing 2.4 all along as I researched this (part of the reason for all the confusion on the issue) and never caught the change to 1.9. But that would make sense.

Second, you've hit the nail on the head with your comment that while there's likely to be sufficient space for the Euro tank, other things could be different thus preventing us from simply plugging it in. But for that risk, we'd probably be driving our i3 already! We're hoping for more information on whether we can easily install the 9-liter tank in place of the 7-liter tank.

 

[TomMoloughney]

I think Tom is going to update us on how many litres he is topping up. That should settle it once and fit all.

I let the tank go down to only 5 miles remaining and it accepted 1.75 gallons, so I do believe he 1.9 gallons is the true capacity. I also think there is a good possibility they are using the same gas tank as the European model, with the volume limited by an added internal bladder or some other way (software?).

 

[MikeS]

May be worth taking the car to a good mechanic and getting him to look inside the tank with the scope they use to inspect engine cylinders.

 

[pdurham]

Now that's a good question: exactly how do they reduce the capacity from 9 liters to 7 liters for the U.S. models? If we could somehow get an accurate answer to that question, we'd be much closer to figuring out whether we could "repair" a U.S. model. Tom (and thanks for your excellent blog by the way), what's your basis for saying "I also think there is a good possibility they are using the same gas tank as the European model, with the volume limited by an added internal bladder or some other way (software?)"? I agree that it would be easier for BMW to do it without actually producing another tank, but was wondering if you had some specific reason for your suspicion (other than common sense).

 

[ultraturtle]

... I also think there is a good possibility they are using the same gas tank as the European model, with the volume limited by an added internal bladder or some other way (software?).

The first component I would check would be what appears to be a circular bulkhead plug here:

If I were BMW (knowing that meeting CARB criteria would almost certainly require some adjustments to the tank volume), I would have engineered the tank in such a fashion that it would be as easy to do as replacing a flat bulkhead plug with one that intrudes into the tank to reduce volume.

 

[mindmachine]

... I also think there is a good possibility they are using the same gas tank as the European model, with the volume limited by an added internal bladder or some other way (software?).

The first component I would check would be what appears to be a circular bulkhead plug here:

If I were BMW (knowing that meeting CARB criteria would almost certainly require some adjustments to the tank volume), I would have engineered the tank in such a fashion that it would be as easy to do as replacing a flat bulkhead plug with one that intrudes into the tank to reduce volume.

The computer system would however also need to know that the tank is smaller in order to project the range of the Rex and display it on the instrument panel.

 

[pdurham]

Excellent information Tom; I'm impressed. Where did you get that excellent picture? Perhaps I could find some more information on the bulkhead plug and whether it's a separate part there?

Is there a way to find out if what you refer to as the "circular bulkhead plug" is a separate part and whether it can be removed and replaced by the Euro version? Perhaps my friend, who is planning on visiting a Belgian BMW dealer today to check on the availability of the Euro tank as a purchasable part, should be checking on the bulkhead plug as well. Perhaps I should have my friend buy the bulkhead plug, if possible (and it looks like it would be much smaller and cheaper than the whole tank), to bring home and compare to the U.S. version of that part. (I just realized that given the time difference, he should have already gone to the dealer. But no word from him yet, so maybe that errand has been postponed.)

As to the computer needing to know the capacity of the tank in order to accurately project the range, that's a valid point as well. But, though I don't know the first thing about all this of course, I doubt that would stop the car from moving. In other words, if the computer incorrectly indicated the range but you knew you had about 1/2 gallon more fuel than the computer thought you did, you'd know that you had an extra 20 miles or so of range beyond what it was projecting. Also, I would imagine the computer has some way of measuring how much fuel remains in the tank (with the result that although it may underestimate the range of a full but "modified" tank, it would provide an increasingly accurate remaining range figure as the tank emptied). All just guesswork on my part.

 

[BrianStanier]

I would suppose its the fuel gauge?

 

[ultraturtle]

Perhaps I could find some more information on the bulkhead plug and whether it's a separate part there?

First off, the existence of such a plug is pure conjecture on my part. Just a guess.

Parts can be found at http://www.etk.cc/bmw/EN/search/selectCar/I01/MCV/BMW+i3+Rex/USA/.

Specifically, the fuel tank can be found at http://www.etk.cc/bmw/EN/search/selectCar/I01/MCV/BMW+i3+Rex/USA/16/16_0921/.

 

[Gonville]

Also here....previously both models had same part number. Not rechecked that but as Tom says some other modification perhaps.

http://www.realoem.com/bmw/partgrp.do?model=1Z43&mospid=56091