MPG meters and relative accuracy.
MPG meters and relative accuracy.
I've been considering a gauge for mpg since my older IX lacks one.
Something like this.... http://www.plxkiwi.com/kiwimpg/index.html
Of course I know the thing isn't going to be that accurate in providing my real world mpg. But I'm interested in knowing if it's accurate from a relative viewpoint. For instance, dynos aren't exactly spot on, but the change between two back-to-back runs is usually accurate. That's the relative part of my above question. I really don't care what the actual is, I just want to make it better and track that accurately.
If I'm in real-time mode and I read 20mpg, and I adjust my pedal to make it read 23mpg am I going to be saving 3mpg at that point in time? With all the variables including a blow off valve which is recirculating 100%, fpRegulator seeing manifold pressure and adding fuel, and the MIVEC advance changing volumetric efficiency, how can this be remotely accurate over a whole tank with boosting? Of course the regulator isn't doing much in vacuum, and the BOV is also doing little without boost, and I'll spend a lot of time worrying about that type of mileage so we can ignore those...... But what about MIVEC in the cruising areas?
I'm really interested in just seeing my real time instant mpg. I was using a boost gauge for this and watching vacuum but I simply want something *more* accurate. I also want statistics like mpg per the last 1 minute, 5 minutes, 10 minutes, etc.
Basically I have some ideas I'm going to be playing with to adjust mileage and I'm interested in making the gauge read lower maintaining the same speed which to me indicates better mileage.
So if I drive down an empty 40mph road for 5 miles and the meter shows 20mpg the whole time, and I start playing with say, a variable intake in open loop. With the fuel trims settled down the gauge might show 22mpg for the same trip over 5 miles at the same speed/temp/humid/etc. Can I say then that my mod netted 2mpg at the same speed? What about different spark patterns such as the MSD creating multiple quick sparks under ~3000rpm..... can this gauge detect that added efficiency?
Obviously I can log IPW and watch the fuel trims.... but if this thing just spits out a number accurate from a relative standpoint, for $80 it's worth it to me.
I'm just a bored tinkerer playing around with mileage which most care little about while I save cash for the bigger mods. I have a daily driver, but the Evo already gets better highway mileage. FAIL I know...... but the topic interests me. While still on the stock turbo I'm curious what I can achieve without hurting performance.
Something like this.... http://www.plxkiwi.com/kiwimpg/index.html
Of course I know the thing isn't going to be that accurate in providing my real world mpg. But I'm interested in knowing if it's accurate from a relative viewpoint. For instance, dynos aren't exactly spot on, but the change between two back-to-back runs is usually accurate. That's the relative part of my above question. I really don't care what the actual is, I just want to make it better and track that accurately.
If I'm in real-time mode and I read 20mpg, and I adjust my pedal to make it read 23mpg am I going to be saving 3mpg at that point in time? With all the variables including a blow off valve which is recirculating 100%, fpRegulator seeing manifold pressure and adding fuel, and the MIVEC advance changing volumetric efficiency, how can this be remotely accurate over a whole tank with boosting? Of course the regulator isn't doing much in vacuum, and the BOV is also doing little without boost, and I'll spend a lot of time worrying about that type of mileage so we can ignore those...... But what about MIVEC in the cruising areas?
I'm really interested in just seeing my real time instant mpg. I was using a boost gauge for this and watching vacuum but I simply want something *more* accurate. I also want statistics like mpg per the last 1 minute, 5 minutes, 10 minutes, etc.
Basically I have some ideas I'm going to be playing with to adjust mileage and I'm interested in making the gauge read lower maintaining the same speed which to me indicates better mileage.
So if I drive down an empty 40mph road for 5 miles and the meter shows 20mpg the whole time, and I start playing with say, a variable intake in open loop. With the fuel trims settled down the gauge might show 22mpg for the same trip over 5 miles at the same speed/temp/humid/etc. Can I say then that my mod netted 2mpg at the same speed? What about different spark patterns such as the MSD creating multiple quick sparks under ~3000rpm..... can this gauge detect that added efficiency?
Obviously I can log IPW and watch the fuel trims.... but if this thing just spits out a number accurate from a relative standpoint, for $80 it's worth it to me.
I'm just a bored tinkerer playing around with mileage which most care little about while I save cash for the bigger mods. I have a daily driver, but the Evo already gets better highway mileage. FAIL I know...... but the topic interests me. While still on the stock turbo I'm curious what I can achieve without hurting performance.
Last edited by acidtonic; Jan 31, 2011 at 09:58 AM.
