Lean Burn 1991 Talon AWD Auto

[naturalextraction]

Hey, good luck on this project. Liked your Del Sol. Drop me a line sometime.

[eee]

Originally Posted by pgfpro

Had some strange results. The slower speeds 50mph,45mph and 40mph are not improving over my steady state 60mph Freeway numbers. This is where my Honda has major improvements.

Its like the auto-trans. is over loading the engine at the slower speeds.

What is it rev'ing at, at 60 mph; and what displacement is the engine?

My guess is the engine might be much more powerful for the gearing; and the gearing is optimized for power / standby power and not fuel efficiency. That is, it could be running at less than half WOT, and thus not so close to its optimal efficiency at all. I think possibly between 60% to 85% WOT are sweet spots.

Leaning out would help by not choking off the air and because you're getting better combustion energy, but I wouldn't go leaner than 1:16.

If you could trick your transmission into changing into the highest gear at 40 mph, then I bet you'd get some decent mpg's at that (even though peak efficiency would be at greater RPM than below 2000).

[pgfpro]

Originally Posted by naturalextraction

Hey, good luck on this project. Liked your Del Sol. Drop me a line sometime.

Thanks!!! Its nice to hear from ya I will drop you an email. Hows your projects coming along?

[pgfpro]

Originally Posted by eee

What is it rev'ing at, at 60 mph; and what displacement is the engine?

My guess is the engine might be much more powerful for the gearing; and the gearing is optimized for power / standby power and not fuel efficiency. That is, it could be running at less than half WOT, and thus not so close to its optimal efficiency at all. I think possibly between 60% to 85% WOT are sweet spots.

Leaning out would help by not choking off the air and because you're getting better combustion energy, but I wouldn't go leaner than 1:16.

If you could trick your transmission into changing into the highest gear at 40 mph, then I bet you'd get some decent mpg's at that (even though peak efficiency would be at greater RPM than below 2000).

At 60mph its at 2600rpm. The displacement is a 2.0L I4

1:16 Lambda? Its running at 1.55+ Lambda right now (22.8+ A/F) at these light loads around 20% T/P angle. But keep in mind that's its making a small amount of boost at these loads so its more closer to a 60% T/P angle N/A.

I'm running a chipped TCU so I can be in OD before 32mph.

[Tygen1]

What's your instant mpg at 22.8:1 AFR? I know it's speed related, but whatever your best is...
I've been tweeking my AFR's a bit and when the temps finally rose up to 40 degrees F, I found I was getting around 70mpg at 50mph with a 16.5:1-17.0:1 AFR, this is on flat to slightly decending road. Flat to slightly accending road it drops to around 65mpg.

[pgfpro]

Originally Posted by Tygen1

What's your instant mpg at 22.8:1 AFR? I know it's speed related, but whatever your best is...
I've been tweeking my AFR's a bit and when the temps finally rose up to 40 degrees F, I found I was getting around 70mpg at 50mph with a 16.5:1-17.0:1 AFR, this is on flat to slightly decending road. Flat to slightly accending road it drops to around 65mpg.

Instant around 35 to 39mpg. Total is 37mpg which matches actual fill up mileage.

Also I'm very pleased with the outcome of this vehicle. Being a all time AWD with and auto design for performance I really can't complain.

[imzjustplayin]

Originally Posted by eee

Leaning out would help by not choking off the air and because you're getting better combustion energy, but I wouldn't go leaner than 1:16.

If you could trick your transmission into changing into the highest gear at 40 mph, then I bet you'd get some decent mpg's at that (even though peak efficiency would be at greater RPM than below 2000).

Actually extremely lean fuel mixtures like past 16:1 would less likely to do damage than a more rich but still lean mixture like 15:1 as something around 15:1 makes the most power for being lean. Best way to use a lean mixture is for light loads only. Very lean and HOT mixtures will burn exhaust valves which is why this balancing act is important.

[GasSavers_maxc]

One cause of burnt exhaust valve can be fuel still burning intensively past the valves.

[pgfpro]

Update:

I have a friend that has another Talon with a identical setup. We have been tuning and testing the car at 30psi on pump premium. Well we had some issues and broke number four piston ring-land. But no problems we had some spare pistons and had it up and running in about 4 1/2 hours. We didn't even have to pull the engine and trans.

These cars are easy to work on

So I'll start on my cars modifications this week.

[pgfpro]

Broke another piston 38psi. LOL

"You have to crack a few eggs in order to make a Cake"

I love breaking things