Picked up 4 MPG!!!!

[93ChevyTBI]

Yeah, that's right. I filled up yesterday morning, drove to work and back, filled up again and for 91 miles, I used exactly 6 gallons. I was getting 11 mpg before my cam swap and new tune. I was absolutely tickled all night last night..so much my wife was getting irritated listening to me. Two things have changed....went from flat tappet 212/218 cam to roller 206/210 cam. Also note from 114 LSA to 111 LSA...111 was "supposed" to give me worse mileage. Change number 2 is 94Blazer383 gave me a re-tune with his wideband hooked up. I don't know if it's the cam or the tune but I am really leaning mostly towards the tune. Keep in mind I did not baby it either...56 miles on a country curvy highway and 35 miles on the interstate going 75 mph...not a measly 70 mph. Also, I passed 6 cars on the country road but didn't kick down hard on it doing so. I have a big truck, well on here it might not be considered big, 33" tires, 4.10's and a 3" lift. How the hell is this thing getting 15 mpg? It didn't get but 14 mpg bone-ass stock. And before you ask, yes the speedo and odometer have been recalibrated. I find it dang near unbelieveable. I was skeptical hearing these claims of 16 mpg or better but not anymore. You can prolly tell I'm still excited about this. I fell in love with my truck all over again yesterday. (when I said this to my wife, she said "Don't be nagging me for sex anymore then, just go drive your truck.") Can you believe that? Actually, it's not far from the truth.

If I really took it easy and checked air pressure in the tires, I think I could get 16 mpg. And if I get Lean Cruise tuned in, who knows, is 18 mpg possible?

After seeing my results, I can see how an expert could get 20 mpg out of a 406 small block that's been mentioned a bunch lately. Hard to believe but possible.

Kudos to 94Blazer383 on the tune.

[noJeepshere]

I picked up 4 mpg's too, but I went from 16-17 stock (265-70-17's, 3.73 gears) to 21 mpg's now. I'm doing an experiment on a kit me and my roommate came up with using plans found on the internet making hydrogen out of water. Fun stuff.

[94Blazer383]

Originally Posted by 93ChevyTBI

Yeah, that's right. I filled up yesterday morning, drove to work and back, filled up again and for 91 miles, I used exactly 6 gallons. I was getting 11 mpg before my cam swap and new tune. I was absolutely tickled all night last night..so much my wife was getting irritated listening to me. Two things have changed....went from flat tappet 212/218 cam to roller 206/210 cam. Also note from 114 LSA to 111 LSA...111 was "supposed" to give me worse mileage. Change number 2 is 94Blazer383 gave me a re-tune with his wideband hooked up. I don't know if it's the cam or the tune but I am really leaning mostly towards the tune. Keep in mind I did not baby it either...56 miles on a country curvy highway and 35 miles on the interstate going 75 mph...not a measly 70 mph. Also, I passed 6 cars on the country road but didn't kick down hard on it doing so. I have a big truck, well on here it might not be considered big, 33" tires, 4.10's and a 3" lift. How the hell is this thing getting 15 mpg? It didn't get but 14 mpg bone-ass stock. And before you ask, yes the speedo and odometer have been recalibrated. I find it dang near unbelieveable. I was skeptical hearing these claims of 16 mpg or better but not anymore. You can prolly tell I'm still excited about this. I fell in love with my truck all over again yesterday. (when I said this to my wife, she said "Don't be nagging me for sex anymore then, just go drive your truck.") Can you believe that? Actually, it's not far from the truth.

If I really took it easy and checked air pressure in the tires, I think I could get 16 mpg. And if I get Lean Cruise tuned in, who knows, is 18 mpg possible?

After seeing my results, I can see how an expert could get 20 mpg out of a 406 small block that's been mentioned a bunch lately. Hard to believe but possible.

Kudos to 94Blazer383 on the tune.

Nice man! I knew we had you dialed in. I am leaning towards the tune myself... You were running pig rich and in open loop all the time so that will kill your milage

[93ChevyTBI]

Originally Posted by 94Blazer383

Nice man! I knew we had you dialed in. I am leaning towards the tune myself... You were running pig rich and in open loop all the time so that will kill your milage

What caused the richness anyway...previous tune or 2 degree advance at the dizzy?

Another question...cold stat hurts mileage. We already talked about it some. But if I switched to a 180 or stock 195, would it help mileage or not...especially since you dialed it in for my current 170? I can see it going both ways..staying the same b/c it was tuned for the 170 or increasing "just because" it 'll run warmer.

What do you think?

I gotta get me a new coolant temp sensor b/c seeing it at 110 degrees all the time is driving me nuts. How am I supposed to know when I have a problem? Gonna try the new PCM to see if it helps the speedo today/tomorrow.

[Blue71]

93ChevyTBI, Man that great, 4 more mile to the gallon, Its is surprising what a Tune can do.

noJeepshere, what kind of cell you running ?

[noJeepshere]

It's all homemade out of a large industrial water filter housing, stainless steel measuring cups and PVC hose. It's only temporary though, I'm going to put a permanent unit in this fall, and do a technical writeup on it.



Sorry to hijack.

[Red94Chev]

[Blue71]

Hey gmc406 why did you delete your post ?
Didn't even think about the difference between canadian gallon and US gallon.
17 to 18 US MPG is more believable, to us USA guys.

[Fast305]

Originally Posted by Blue71

Hey gmc406 why did you delete your post ?
Didn't even think about the difference between canadian gallon and US gallon.
17 to 18 US MPG is more believable, to us USA guys.

I don't know, my 350 was knocking on 20 mpg consistently. The 305 prior to that pulled down 23 mpg as an all time best. In a 5,000 lbs G20 Van.

[04chevy71]

im gettin 23 to 24 at 75 mph to 80 mph

[noJeepshere]

Originally Posted by Red94Chev

[94Blazer383]

Originally Posted by 93ChevyTBI

What caused the richness anyway...previous tune or 2 degree advance at the dizzy?

Another question...cold stat hurts mileage. We already talked about it some. But if I switched to a 180 or stock 195, would it help mileage or not...especially since you dialed it in for my current 170? I can see it going both ways..staying the same b/c it was tuned for the 170 or increasing "just because" it 'll run warmer.

What do you think?

I gotta get me a new coolant temp sensor b/c seeing it at 110 degrees all the time is driving me nuts. How am I supposed to know when I have a problem? Gonna try the new PCM to see if it helps the speedo today/tomorrow.

You actually have 2 sensors. One for the gage and one for the ECM. The one for the ECM is the one that is close to your thermostat housing on your intake, which is the one you were having problems with. The other one is in the drivers side head and is for the gage. I guess it is possible for there to be 2 different temp readings between the 2 sensors since they are in different locations. You will never know what the one on your thermostat is reading unless you hook up the laptop. I have a 195 thermostat in mine and I think my factory gage reads low, but dataloging shows the correct temp. Some of it probably has to do with the fact that the factory gages in these trucks are inaccurate POS. I would just leave it alone, I think you will be chasing you tail.

[gmc406]

Originally Posted by Blue71

Hey gmc406 why did you delete your post ?
Didn't even think about the difference between canadian gallon and US gallon.
17 to 18 US MPG is more believable, to us USA guys.

Sorry guys, I thought I was posting the obvious and I felt kinda silly.

But, to all my American friends, my fuel milage is calculated using the Canadian gallon which is slightly larger than the Americam gallon. I haven't figured it out in US gallons but I'm guessing it would be about 17-18.

[93ChevyTBI]

Originally Posted by gmc406

Sorry guys, I thought I was posting the obvious and I felt kinda silly.

But, to all my American friends, my fuel milage is calculated using the Canadian gallon which is slightly larger than the Americam gallon. I haven't figured it out in US gallons but I'm guessing it would be about 17-18.

Ahhhhhh, that would explain things bit. Here's another for ya then. LOL!!

Seriously though, I didn't know a Canadian gallon was different. I thought a gallon is a gallon is a gallon. Just learned something new right there.

[noJeepshere]

American gallon= 3.78 liters

Canadian gallon= 4 litres

It's only a little different, but enough to make a difference in numbers.

[pfk]

Originally Posted by noJeepshere

American gallon= 3.78 liters

Canadian gallon= 4 litres

It's only a little different, but enough to make a difference in numbers.

Just to maintain accuracy in the thread,

Canadian gallon (UK Gallon) = 4.546092 L
compared to US gallon = 3.785412 L

you are right though, it does make a big difference in mpg calculations

[hornsfan10609]

Originally Posted by 94Blazer383

You were running pig rich and in open loop all the time

No wonder your mileage sucked!

[93ChevyTBI]

Originally Posted by hornsfan10609

No wonder your mileage sucked!

Indeed. While we were logging, coolant temp was staying at 110. We wiggled the wire and it jumped to 170...hence the open loop. Still gotta fix that.

[93ChevyTBI]

update....70/30 mix of highway and city got me 13 mpg

checked my tire pressure last night when I filled up and it was 24-25 across the board. Yeah, I know...that's low. I always thought 32 psi was the standard until I read that one thread about 40-50 psi, which I thought was BS. My tires' rating are 2510 lbs @ 50 psi. Does that mean I need to air up to 50 or just that they can handle it?

So I need the verdict: 32 psi or 50? Hopefully it increase mileage 1-2 mpg.

[94Blazer383]

Originally Posted by 93ChevyTBI

update....70/30 mix of highway and city got me 13 mpg

checked my tire pressure last night when I filled up and it was 24-25 across the board. Yeah, I know...that's low. I always thought 32 psi was the standard until I read that one thread about 40-50 psi, which I thought was BS. My tires' rating are 2510 lbs @ 50 psi. Does that mean I need to air up to 50 or just that they can handle it?

So I need the verdict: 32 psi or 50? Hopefully it increase mileage 1-2 mpg.

I run about 32-35