BUILD THREAD 87 Cutlass EFI build: 9/13/23..NEW STUFF!

[Injectedcutty]

15mpg?! Who did your tune?

Hey, I'll take it. That's double what my SBC/TH350 used to get. To think I'm running a cammed 5.3/80E with a 3400rpm stall and 3:73's I'm ok with it. The AFR gauge stays steady at stoich the whole time. My tooner nailed it! Still need to iron out hot idle surging with fans on, but that's simple and I've been lazy.

 

[64nailhead]

I don't remember your cam specs, but I'll say you can get better mileage based on the sound of your cam. The dilemma comes in that you have to get past the cam lope when cruising and that might be 3000-3500 rpm's. Not a problem if you want to cruise at 80+ mph lol.

If your short term correction is keeping you at 14.7, then hookup a low budget vacuum gauge and drive at a steady speed, with the converter locked in 4th gear of course, and where the vacuum reading is the highest is most generally where you will get best fuel economy.

Big cams and fuel economy - they get along about as well as a wild cat and dog.

 

[Injectedcutty]

I don't remember your cam specs, but I'll say you can get better mileage based on the sound of your cam. The dilemma comes in that you have to get past the cam lope when cruising and that might be 3000-3500 rpm's. Not a problem if you want to cruise at 80+ mph lol.

If your short term correction is keeping you at 14.7, then hookup a low budget vacuum gauge and drive at a steady speed, with the converter locked in 4th gear of course, and where the vacuum reading is the highest is most generally where you will get best fuel economy.

Big cams and fuel economy - they get along about as well as a wild cat and dog.

Attached is quick specs on cam Jim. I was cruising most of the way at around 60mph because it was two lane country road and 55mph limit. The Innovate gauge reads vacuum along with AFR and was staying around 16 while mowing down the road. I still need to do a dyno session as my engine is a tad different than Mike's LS1 in the wagon, but dang he nailed it close!

 

[motorheadmike]

Also, are you p*ssy footing and hyper-miling it or are you stomping on it off every light, downshifting every chance you get, and just sitting there listening it to idle just to make Greta cry and you smile?

15 mpg is pretty good.

 

[Texas82GP]

Also, are you p*ssy footing and hyper-miling it or are you stomping on it off every light, downshifting every chance you get, and just sitting there listening it to idle just to make Greta cry and you smile?

15 mpg is pretty good.

You saw his cruise video right? He's just grandpa-ing around town. 🤣

 

[Injectedcutty]

Also, are you p*ssy footing and hyper-miling it or are you stomping on it off every light, downshifting every chance you get, and just sitting there listening it to idle just to make Greta cry and you smile?

15 mpg is pretty good.

Yesterday I was cruising on the backroads, but best believe any chance I get to stomp it and hear giggles from the back seat I'm on it. The wife said at one point "doesn't feel as powerful as your last engine" to which I obliged with a hardcore hit when she wasn't expecting it lol. She said "nevermind I'll be quiet now." Put that in the W column.

 

[motorheadmike]

Yesterday I was cruising on the backroads, but best believe any chance I get to stomp it and hear giggles from the back seat I'm on it. The wife said at one point "doesn't feel as powerful as your last engine" to which I obliged with a hardcore hit when she wasn't expecting it lol. She said "nevermind I'll be quiet now." Put that in the W column.

 

[melloelky]

never mind that sh*t Scott,ultimately it's about spg-smiles per gallon.you're there.

 

[motorheadmike]

Hey, I'll take it. That's double what my SBC/TH350 used to get. To think I'm running a cammed 5.3/80E with a 3400rpm stall and 3:73's I'm ok with it. The AFR gauge stays steady at stoich the whole time. My tooner nailed it! Still need to iron out hot idle surging with fans on, but that's simple and I've been lazy.

Double check your fuel trims. +/-5% means it's good.

 

[64nailhead]

You should see better mileage IMO, but not crazy better, maybe high teens. Are you sure you're odometer is reading mileage correctly?

Either way, I'm with Melloelky on this one - SPG are way more important MPG.

And that is a great street cam. It leaves some on the table at the top, but how it drives is what makes it such a great cam. Tick really doesn't have any duds.