MarkD Chips on a 318i - questions

[lespaul]

I hear the MarkD chip is the one to get for my 318i. My questions are:

1) Does anyone have experience with the 91 and/or 93 octane chips.

2) Does the 91 make a noticeable difference?

3) Is there a big difference between the 91 and 93?

4) What exactly will I notice with BOTH chips?

5) Gas mileage improvement or does it make gas mileage worse?

6) Is installation difficult?

7) Will it improve the lag in the lower rpms of 1st and 2nd?

Thanks!

[gearheadE30]

Yes, it is definitely the one to get.

1. I have a 93 octane chip, but have never driven a 91 octane
2. yes, but the 93 makes much more of a difference.
3. I'm inclined to think so based on reviews from M42club. This is probably because the M42 is reletively high compression with no knock sensors.
4. Rev limit at 7150 rpm, much better idle and low rpm response, significantly improved driveability and slightly wider torque curve. I don't think peak hp or torque increases too much, though. The chips were (apparently) tuned on the street more than the dyno.
5. My mileage improved by one or two MPG because I use less of the gas pedal and need less rpm. This is based on averaging the miles per gas tank from the odometer.
6. Not really. Open the glovebox, unscrew the upper panel that has the airbag sticker on it, there are bolts on either side of the ECU. Loosen the bolts, but it is just a clamp. Pop the plug out. It has a lever lock on it, don't just pry it out. The case then needs to be unscrewed and popped open, and the chips switched.
7. Lag? If you are talking about hanging revs or responsiveness, yes. Otherwise, it may be your TPS or your AFM.

[lespaul]

thanks so much.. Now I'm trying to calculate the difference in 91 and 93 octane per tank! Is it a lot? Haven't really noticed at the pump recently.

Yes, it is definitely the one to get.

1. I have a 93 octane chip, but have never driven a 91 octane
2. yes, but the 93 makes much more of a difference.
3. I'm inclined to think so based on reviews from M42club. This is probably because the M42 is reletively high compression with no knock sensors.
4. Rev limit at 7150 rpm, much better idle and low rpm response, significantly improved driveability and slightly wider torque curve. I don't think peak hp or torque increases too much, though. The chips were (apparently) tuned on the street more than the dyno.
5. My mileage improved by one or two MPG because I use less of the gas pedal and need less rpm. This is based on averaging the miles per gas tank from the odometer.
6. Not really. Open the glovebox, unscrew the upper panel that has the airbag sticker on it, there are bolts on either side of the ECU. Loosen the bolts, but it is just a clamp. Pop the plug out. It has a lever lock on it, don't just pry it out. The case then needs to be unscrewed and popped open, and the chips switched.
7. Lag? If you are talking about hanging revs or responsiveness, yes. Otherwise, it may be your TPS or your AFM.