remove EAT chip for the summer?

[BigTed00]

Here is the situation. My car has an EAT chip, and its pretty nice, but the problem is gas is getting really high, and this summer it will only go up. I have about 10,000 miles of driving up and down the east coast ahead of me this summer, and the thought of paying $3.XX for 93 octane makes my wallet shudder. Is it possible or a good idea to take out the EAT chip for the summer so I can put 87 or 89 octane in?

[SharkmanBMW]

you should be getting better fuel econmy with the chip, so it likely balances...
and many would say you should run high octane anyways
I don't have the chip, but I use 91 or better, which is supreme here, except for Petro Canada that has 94 - (and 94 makes no difference in either of my cars.)

[632 Regal]

go with 91 if you dont get knock, the mileage savings with the chip will offset the cost of fuel ples it has better performance with less peddle.

[Kalevera]

I once did the calculations. If you don't drive the car like an idiot, it's only economical to use an EAT chip when regular gas prices are above about 2.50 a gallon. Hence I removed my EAT chip in November, when gas started going back down to ~ 2.20 in Ohio. This was based on my mixed mileage being about 19 miles to the gallon with EAT, around 16 mpg without.

Think about it. As gas price levels increase, the percentage difference decreases between regular and premium prices. That maximizes the effect of any mileage improvement achieved out of a chip. In my case, it was 1 - 2 MPG on a good tank.

Write an equation for each type of gas at certain price levels that factors in the price and the (expected or known) mileage, compare the results and see for yourself. Ceteris paribus: producers/distributors don't start changing the percent difference between prices of the types of gas -- it seems to have been pretty consistent over the past year or so that I've been watching this kind of stuff.


best, whit

[632 Regal]

soo....whats the answer, keep it or toss it till summer fuel rolls in?

I once did the calculations. If you don't drive the car like an idiot, it's only economical to use an EAT chip when regular gas prices are above about 2.50 a gallon. Hence I removed my EAT chip in November, when gas started going back down to ~ 2.20 in Ohio. This was based on my mixed mileage being about 19 miles to the gallon with EAT, around 16 mpg without.

Think about it. As gas price levels increase, the percentage difference decreases between regular and premium prices. That maximizes the effect of any mileage improvement achieved out of a chip. In my case, it was 1 - 2 MPG on a good tank.

Write an equation for each type of gas at certain price levels that factors in the price and the (expected or known) mileage, compare the results and see for yourself. Ceteris paribus: producers/distributors don't start changing the percent difference between prices of the types of gas -- it seems to have been pretty consistent over the past year or so that I've been watching this kind of stuff.


best, whit

[Kalevera]

Keep it as long as gas prices are high. Higher the better. Just as long as there's an actual mileage improvement in using regular vs premium and the oil companies keep the percent differences between the different fuel grades about the same.

I'm all for high gas prices. Too many cars on the road as it is. How much time do you spend in traffic every day?

best, whit

[BigTed00]

lots. I commute 10 miles a day back and forth from school and work, in that time its a 50/50 mix of highway (80 mph) and city driving. My OBC tells me that I get 16 mpg, which is fine considering most of my time is spent stop-and-go in 2nd and 3rd gear. I just filled up today @ 2.80 and I thought to myself, man I wish I could be putting in $2.53 regular....But what you say actually makes sense, I think I'll just leave it in

[Evan]

ceteris paribus! you just took me back to freshman econ class.

[DueyT]

I keep mine in no matter what...I had to run mid-grade (89) anyway per the owner's manual so the extra 5¢/litre to do supreme (91) is well worth the extra 8-10% mileage I get from the chip.

Mein zwei centen...

Cheers,
Duey

[Robert K]

I have to admit that I'm not real certain I ever experienced much improvement in my mpg's with my EAT chip. I took it out months ago when premium hit above $3.00 per gallon here in Kentucky and haven't put it back in since. It's bad enough paying $2.60 a gallon now for regular 87 octane.

After reading some of the above posts, I did some math. Here's what I found. Assuming a 21 gallon tank, if you filled it with 87 octane at $2.50 per gallon (without EAT chip installed) and drove all highway miles and got 23 mpg (which is pretty consistent for me), you'd be able to go 483 miles. That calculates out to $.1087 per mile.

If you put 21 gallons of 91 octane at $2.70 per gallon (with EAT chip installed) and drove all highway miles and got 25 mpg (which I can't say I ever got 25...maybe 24 at 60 mph), then you could go 525 miles. That calculates out to $.108 per mile.

So the real issue is whether you actually get better mpg's with the EAT chip. If you don't, then it will certainly cost more overall to have to purchase high octane fuel. Frankly, I've had my EAT chip out for a few months and I don't miss the performance. I do however like saving $4-5.00 per fillup. I suppose it all comes down to what you want to spend your money on.

Grace and peace,

Robert K
1991 535i