No pics unfortunately - it was fun to drive but had a crazy stiff clutch - I honestly cant remember if it was a 3 speed or 4. It definitely ran out of breath early in the rpm band - but could pull like a tug boat!
Best octane fuel for fuel eceonomy? (5.3L only)
- Thread starter cfmistry
- Start date
Disclaimer: Links on this page pointing to Amazon, eBay and other sites may include affiliate code. If you click them and make a purchase, we may earn a small commission.
swathdiver
Full Access Member
They came with both, most of them 3-speeds, gone by 1981 if memory serves. Fun stuff!
What is responsible for better fuel mileage at the same * light throttle opening during cruise* ??........TIMING
The more timing without knock/detonation the more torque the better the mileage.
What allows more timing without KR? (Knock retard)
Cooler intake air.... IAT , allows more timing.....look at a tune map timing vs IAT
Higher octane fuel....allows more timing to be utilized
Lower engine temp ECT ....less prone to knock/det
Your highest amount of timing will be at the lightest load/throttle like cruising at 40 mph.
OEM tuning is for the minimum fuel octane available everywhere, or for performance vehicles they stipulate in the manual the minimum requirement.
Aftermarket tuning can give you more timing if you are dedicated to using high octane fuel, add a real cold air intake and its even better.
PS, you cant really do MPG comparison with gas vs E85 as it has ~27% less energy than gas....the only good thing is the higher octane rating. You would have to do a price comparison with total miles driven.
The more timing without knock/detonation the more torque the better the mileage.
What allows more timing without KR? (Knock retard)
Cooler intake air.... IAT , allows more timing.....look at a tune map timing vs IAT
Higher octane fuel....allows more timing to be utilized
Lower engine temp ECT ....less prone to knock/det
Your highest amount of timing will be at the lightest load/throttle like cruising at 40 mph.
OEM tuning is for the minimum fuel octane available everywhere, or for performance vehicles they stipulate in the manual the minimum requirement.
Aftermarket tuning can give you more timing if you are dedicated to using high octane fuel, add a real cold air intake and its even better.
PS, you cant really do MPG comparison with gas vs E85 as it has ~27% less energy than gas....the only good thing is the higher octane rating. You would have to do a price comparison with total miles driven.
donjetman
Full Access Member
- Joined
- Oct 22, 2018
- Posts
- 1,531
- Reaction score
- 2,714
2+ yrs later:
I am again occasionally mixing in about 5 gals of e85 when filling up w/e10 93 octane.
Cost is $2.60/gal for e85 and $3.65/gal for 93.
I can't notice a mpg hit to my local driving, so its a win.
But the station is 20 miles away so I don't get the chance to do this very often.
And everyone here shoukd know by now "I take it easy on the ole beast".
Last edited:
Similar threads
