Looking for better gas mileage

[z122643]

So I'm seeking better gas mileage for open road driving. I'd like to have 2,800rpm at 70mph. The 3.91 ratio diffs. in my iX give me 3,200rpm at 70mph and I average 25mph +/-1mpg.

I know that euro model iX had 3.73 and 3.64 ratios. In order to still retain some "power" I was thinking of using the 3.73 which, according to sources, should be 3,080rpm at 70mph.

Thoughts, comments, complaints...

[ghatid]

So I'm seeking better gas mileage for open road driving. I'd like to have 2,800rpm at 70mph. The 3.91 ratio diffs. in my iX give me 3,200rpm at 70mph and I average 25mph +/-1mpg.

I know that euro model iX had 3.73 and 3.64 ratios. In order to still retain some "power" I was thinking of using the 3.73 which, according to sources, should be 3,080rpm at 70mph.

Thoughts, comments, complaints...

Wait, are you getting 25mpg? That's pretty freakin good, isn't it for a 325ix?

[stonea]

I'm averaging about 21 daily driving city/highway, I've never even gotten close to 25, hell I only get about 26 on the highway in the Z3. Also good luck finding those diffs, I've been looking for while and its not easy. Plus you're probably gonna spend $600 on just 2 new diffs. I'd just live with what you got.

[z122643]

Diffs are available. I rebuilt the engine with efficiency in mind. It originally got 17city 22 hwy. I get 19-21 mpg city. On long road trips between SoCal and Colorado, I get between 23-26

[downforce22]

Ive only seen one 3.73 front diff on german ebay.

Also Ive got the 3.64s on my euro iX and picked up a spare 3.64 front. I haven't seen a 3.64 vc rear though. You would be better off finding a used iX ingermany to try and get the diffs, but why?

The e30 is not a prius. Get a 325e if you want fuel economy. You get between 19-23 mpg average in an iX, live with it.

[nando]

how are you getting 3200rpm at 70mph with a 3.91 when my 4.10 is 3500 at 75mph?

also, the ix is pretty slow already with the short gearing. I don't think I could bear it with anything taller.

[CorvallisBMW]

The fuel mileage difference between 3.91 and 3.73 would be unnoticeable. Save your $ for a proper tune-up, remove any excess weight in the car (junk, tools, etc), don't drive like a douche, etc. All will get you far better mileage than a diff swap, and for much less money.

[audiquattrot]

I WISH I got 25mpg.

[rcsoundn1]

Best i ever got on a vert was 27, I average 23 mixed driving

[Bimmer_man]

For my car according to my obc I get 28 haha. A lot of my driving was on the freeway and I throw the car on neutral on hills. Mainly it's driving habits but the ix should get anywhere from 23-25. If you want better economy get a eta or something. But I know a couple of things you can do to get better mpg.

K&n drop in filter.
New ignition stuff
free flowing exhaust
Good maintenance practices
And strip out anything you don't need to lighten the car.

[packratbimmer]

Run 75W-90 in your diffs and Redline ATF in your tranny.

25 on the highway is right on target for a properly running iX.

Good luck!

[BklynE30Dude]

My 2 cents. I run a stock setup.

In NYC, I average 17 mpg. That's reality for all of us in this city though.

This weekend on all highway driving. With weight of 4 adults in car, I averaged 25 mpg over 200 miles. And that was me driving about 75 mph and keeping an eye on the mph gauge.




Sent from my iPhone using Tapatalk

[325ixa]

and I throw the car on neutral on hills

this is wrong, dont do this.

[iXerces]

Long lights (i.e. lots of idling) in Lexington kill me, so much of the time I can't even get above 15 mpg city here. Earlier, during my stint in Fargo, I was usually closer to 17 or so in the city unless it was very cold and then I plummeted to 11-12 mpg.

Over the last two years, I've usually been in the 25 mpg range for freeway driving. Once I hit 30, but that was at 65 mph drafting behind my uncle's RV.

[The Dark Side of Will]

this is wrong, dont do this.

Depends... If he chucks it in neutral, he's burning gas while it idles. If the hill is steep enough, then lifting off the gas results in the DME shutting the injectors off and maximum engine braking... but that only applies if the hill is steep enough to keep the car from losing speed going down it. If the hill isn't steep enough, you'll need to use a little bit of throttle to maintain speed... more gas than idling? I dunno.