EAT chip fuel economy?

[pundit]

I'm probably jumping the gun a bit here (don't even own an E34 yet!) but I was wondering, that with normal driving (535i -auto), would one expect any improvement in fuel economy versus the standard ECU chip? Better? Worse? No difference? Has this been ever accurately documented? - Cheers :)

[Warren N.CA]

Mine is an '89 535i manual. It also is much better driving, with faster acceleration. Not a bad combination. On a recent 2500 mile round trip through the Rocky Mountains, it averaged 26mpg, highway.



I'm probably jumping the gun a bit here (don't even own an E34 yet!) but I was wondering, that with normal driving (535i -auto), would one expect any improvement in fuel economy versus the standard ECU chip? Better? Worse? No difference? Has this been ever accurately documented? - Cheers :)

[Russell]

My fuel economy with my 525i has stayed about the same. However, the car runs much better, less downshifitng and more power when you need it. I used Chevron 93 octane before the EAT chip. Mine will get a little better performance/gas mileage with higher octane because of the knock sensors.

I have also noticed that if I drive the car hard, mileage will drop a bit more than before. Not unexpected. I aslo average around 27-29 at highway speeds on a trip. Average intown/highway mix during my daily commute is 22-24 mpg.


I'm probably jumping the gun a bit here (don't even own an E34 yet!) but I was wondering, that with normal driving (535i -auto), would one expect any improvement in fuel economy versus the standard ECU chip? Better? Worse? No difference? Has this been ever accurately documented? - Cheers :)

[Ted K]

EAT chip in a 90 535 5 speed. Great performance, mileage for every day driving around 20-21 mpg. All Freeway around 25.

[MarkD]

If you don't have an E.A.T. chip, there is still time to order and get one this week. (I'll ship by Fedex) In almost all 535's and 525's you will see a 3 to 5% decrease (improvement) in fuel consumption, but many have seen a slightly better saving.

MarkD

[Dick Schneiders]

your fuel *usage* will decrease by 3 to 5%, and that your mpg will increase. Mine certainly did in my 1991 525i by 1.5 to 2 mpg, along with a smoother idle and acceleration.


If you don't have an E.A.T. chip, there is still time to order and get one this week. (I'll ship by Fedex) In almost all 535's and 525's you will see a 3 to 5% fuel decrease, but many have seen a slightly higher saving.

MarkD

[Phil Sanderson]

a chip for my 525i. Did you not receive it?

Phil

[MarkD]

your fuel *usage* will decrease by 3 to 5%, and that your mpg will increase. Mine certainly did in my 1991 525i by 1.5 to 2 mpg, along with a smoother idle and acceleration.

Thanks Dick,
I wrote that in the middle of the night when I woke up to turn down the thermostat, and made a detour to see what was happening in the forum. (and didn't proof read it). I edited the post and it should be clear now.

Mark

[MarkD]

a chip for my 525i. Did you not receive it?

Phil

Hello Phil,

I received it, but was not able to respond yet. I'll do that in a few hours.

Thanks

Mark

[an535i]

16 MPG City
21 MPG Highway

Im not sure if this is normal, but its about all I can muster out of my car. EAT Chip / Automatic trans 90 535i

[JonE]

I got 1-2 mpg better mileage with the chip in my 535iA. Performance a noticeable improvement and smoother idle. Before chip city=15mpg, EAT=17mpg. Haven't done enough highway, but did get about 24mpg a couple times this last summer, driving about 70mph.

[willobmw]

Have you replaced the oxygen sensor? Sounds a little low. I get around 17-18 in the city and I have gotten over 25mpg on the highway. Same car 1990 535ia with no chip. And I know it is hard but stay off the gas.
Will Ollison