Unmetered Air leak = Better MPG??? - Page 4 - Fuel Economy, Hypermiling, EcoModding News and Forum

Tygen1 · 10-09-2009, 12:12 PM

46mpg on the way to work today, much better than the previous week. Filled up when I got to work. 42mpg, I was at 40mpg when I did this change, it improved my average by 2

We'll see how next week goes....

Tygen1 · 10-10-2009, 09:43 AM

I did check my ignition advance yesterday. At 50mph and a 21TPS (just enought throttle to keep it rolling and not loose speed) the advance was 35-36. Going slightly downhill at 50mph and a 19-20TPS the advance was 39-40, which I presume is max. Idle TPS is 17. I need to test this with the line pluged back in to compare. This is quite a mystery, I did a little drive last night, I often drive this route and have never gotten better than 40mpg, last night I got 42. It definatly is working...and I'm not getting any pinging or surging that is typically associated with vacuum leaks.

Christ · 10-10-2009, 11:10 AM

Quote:

Originally Posted by Tygen1

I did check my ignition advance yesterday. At 50mph and a 21TPS (just enought throttle to keep it rolling and not loose speed) the advance was 35-36. Going slightly downhill at 50mph and a 19-20TPS the advance was 39-40, which I presume is max. Idle TPS is 17. I need to test this with the line pluged back in to compare. This is quite a mystery, I did a little drive last night, I often drive this route and have never gotten better than 40mpg, last night I got 42. It definatly is working...and I'm not getting any pinging or surging that is typically associated with vacuum leaks.

So if you're at max-advance, you should be making a bit more power, too, I'd presume. Except for the leaner burn, maybe. So maybe you just didn't lose any power?

I would have to wonder what would happen at this point if your knock sensor was still plugged in?! I bet that thing would be going crazy!

Tygen1 · 10-10-2009, 01:54 PM

The knock sensor goes crazy no matter what

It's pretty much useless on the ZX2

Tygen1 · 10-15-2009, 08:36 PM

We have a winner!
P0171, Bank 1 lean, Fuel Trim Maxed Out. Nice

I'm lean burning

Just wish I knew the real AFR, so I could see if I was in danger, Oh well, these engines are cheap enough, LOL! Took a week for the SES to come on. I guess the computer was determined to get it right. The crazy thing is, it just seems to get better and better. Probably I'm just learning to drive it better lean. It can take a bit more throttle and not kill the mpg's and it takes more throttle to climb the hills. Also, I just did 47mpg on the way home yesterday, that's as good as I did on summer gas in 90 degree weather. Now it's winter gas and 50 some degrees. Wish I had found this in the summer. Now to get the HAI hooked up and some more aero mods and this winter may be better than summer

Horray for Vacuum Leaks!

Christ · 10-15-2009, 10:15 PM

Quote:

Originally Posted by Tygen1

We have a winner!
P0171, Bank 1 lean, Fuel Trim Maxed Out. Nice

I'm lean burning

Just wish I knew the real AFR, so I could see if I was in danger, Oh well, these engines are cheap enough, LOL! Took a week for the SES to come on. I guess the computer was determined to get it right. The crazy thing is, it just seems to get better and better. Probably I'm just learning to drive it better lean. It can take a bit more throttle and not kill the mpg's and it takes more throttle to climb the hills. Also, I just did 47mpg on the way home yesterday, that's as good as I did on summer gas in 90 degree weather. Now it's winter gas and 50 some degrees. Wish I had found this in the summer. Now to get the HAI hooked up and some more aero mods and this winter may be better than summer

Horray for Vacuum Leaks!

I can only wonder how long it was like this before you noticed it?

Tygen1 · 10-15-2009, 10:47 PM

I noticed it imediatly, you might remember the orginal thread where I thought changing my pulleys gave me some great mpg gains. That's when I forgot to hook that line back up and I noticed the change on my test drive. It was a couple days later that I found the line and this journey to understand began.

Anyone got a spare wideband they wanna loan me

Christ · 10-15-2009, 10:48 PM

Well, I had a UEGO, but I'm not sure where it's at...

So those pulleys netted nothing?

Tygen1 · 10-16-2009, 08:48 PM

Nope, no gain from the pulleys

But it is quieter now

moorecomp · 10-16-2009, 11:47 PM

This has been driving me nuts, trying to figure out what the line to the intake duct could be for. I found this post on teamzx2:

TeamZX2.com - View Single Post - Little hose thingy?

The air pulled from the intake tube is routed through a device called a vaccuum booster/check valve. The air is drawn through a boost venturi and the vaccuum level is increased. Cool.