That says it has 7.8 to 1 Compression ratio. Why are you buying high octane ?
And some form of EFI. And a CD of .457.
What rpm do you turn on the highway at 65 mph?
How much of you driving is highway, and how fast do you go?
Is it 4WD/AWD?
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Water injection and alcohol fuel 14
- Thread starter Slim3
- Start date
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That says it has 7.8 to 1 Compression ratio. Why are you buying high octane ?
And some form of EFI. And a CD of .457.
What rpm do you turn on the highway at 65 mph?
How much of you driving is highway, and how fast do you go?
Is it 4WD/AWD?
140Airpower
Automotive
Wow, this is going to be an expensive vehicle to drive no matter what you do. 12 mpg is doing well IMHO. I used to get 13.3 in my '72 Camaro.
Mike, do you get pinging when lugging it? 7.9 CR is that low for reasons of luggability, like rpms in the 1,500 range under load. If you get pinging, a simple, plain-water injection system will stop that. It will also clean the carbon out and that might help your mileage just a tad. But, normally water injection is not known to increase fuel mileage no matter what the claims of people selling systems. Also, substituting alcohol should reduce your mileage. In fact, 92 octane should reduce your mileage just a couple of percent compared to 87. If you are using 92 to avoid pinging on 87 then a little bit of water injection, just enough to stop pinging on 87, would probably be the best bet. Save you some money.
Mike, do you get pinging when lugging it? 7.9 CR is that low for reasons of luggability, like rpms in the 1,500 range under load. If you get pinging, a simple, plain-water injection system will stop that. It will also clean the carbon out and that might help your mileage just a tad. But, normally water injection is not known to increase fuel mileage no matter what the claims of people selling systems. Also, substituting alcohol should reduce your mileage. In fact, 92 octane should reduce your mileage just a couple of percent compared to 87. If you are using 92 to avoid pinging on 87 then a little bit of water injection, just enough to stop pinging on 87, would probably be the best bet. Save you some money.
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- #123
Pat, At the time of the tests of the injected Ethanol/water in the Dodge 318's, I adjusted the flow into the intake manifold at high RPM and adjusted it rich until it stumbled giving it the max alcohol/water that it could handle in addition to the preset gasoline, then leaned that alcohol/water down until the engine cleared up and then ran a 1/4 mile acceleration run. I was not looking at or for fuel mileage. I only wanted to confirm what the company said and that was that a 50/50 alcohol/water mix gave the best hp. The increase in power was easy to feel and the time in a quarter mile confirmed it.
What you said earlier that the power increase could very well have been due to a lean gasoline setting and the added fuel (alcohol) gave it a richer mixture and more power. However the same tests run with 180, 190 and 200 proof and a 160, 150 and plain water tested the same way showed little to no increase in power over just gasoline. That is what surprised me and I couldn't see why.
The Triumph TR-7 with the compression raised (too high) was run on straight alcohol/water and no gasoline at all and I had jacked the compression up so high I couldn't even start it on gasoline without serious detonation with Turbo Blue with an octane booster in it. So I had to design a pair of intake air stream heaters for both constant velocity carburetors to start it on alcohol.
The acceleration tests were very dramatic but I had to make my own metering needles for the carburetors and I found that ignition timing ended up at about the same as gasoline. I guessed that the slow burn of the alcohol would normally require a more advanced timing but the high compression sped up the flame to bring it back to what gasoline required.
Slim3
What you said earlier that the power increase could very well have been due to a lean gasoline setting and the added fuel (alcohol) gave it a richer mixture and more power. However the same tests run with 180, 190 and 200 proof and a 160, 150 and plain water tested the same way showed little to no increase in power over just gasoline. That is what surprised me and I couldn't see why.
The Triumph TR-7 with the compression raised (too high) was run on straight alcohol/water and no gasoline at all and I had jacked the compression up so high I couldn't even start it on gasoline without serious detonation with Turbo Blue with an octane booster in it. So I had to design a pair of intake air stream heaters for both constant velocity carburetors to start it on alcohol.
The acceleration tests were very dramatic but I had to make my own metering needles for the carburetors and I found that ignition timing ended up at about the same as gasoline. I guessed that the slow burn of the alcohol would normally require a more advanced timing but the high compression sped up the flame to bring it back to what gasoline required.
Slim3
msquared48
Structural
140airpower:
I get no pinging whatsoever with the 92 octane, even under high load as in towing a 30 foot trailer over the summit climb over Stevens Pass at 50 mph. - keeps the plugs clean as they foul at lower octanes.
Mike McCann
MMC Engineering
I get no pinging whatsoever with the 92 octane, even under high load as in towing a 30 foot trailer over the summit climb over Stevens Pass at 50 mph. - keeps the plugs clean as they foul at lower octanes.
Mike McCann
MMC Engineering
hydroman247
Mechanical
12mpg from a road vehicle :O
I think you can be shot in the UK for that.
I think you can be shot in the UK for that.
140Airpower
Automotive
Mike, I'm surprised you get fouling with 87. Does anyone have an insight into that?
patprimmer
New member
It's got me completely beat.
Regards
Pat
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Regards
Pat
See FAQ731-376 for tips on use of eng-tips by professional engineers &
for site rules
140Airpower
Automotive
The only thing that comes to mind is oil consumption vs detergent in the gas. 92 is apt to have more detergent. The work-around that comes to mind is the next hotter range of plug for 87. But then you are more likely to get pinging. Also, water injection in an oil consuming engine is less appealing due to cooler running and plug fouling.
Mike, how much oil do you burn?
Mike, how much oil do you burn?
msquared48
Structural
This engine is tight - no oil burning, just leaks a little at the crankcase - need to replace the seals when it gets a lot worse, but OK for now.
Mike McCann
MMC Engineering
Mike McCann
MMC Engineering
msquared48
Structural
For the record, this is not our primary vehicle, but our work, hauling, and recreational vehicle. It is not used for day to day excursions. At that mileage rate, I could never afford it. We have a 2007 Prius for that. It has over 10,0000 miles on it now.
Interesting thing for this vehicle is that it has never even come close to failing emissions. Always less than 10% of allowables.
Mike McCann
MMC Engineering
Interesting thing for this vehicle is that it has never even come close to failing emissions. Always less than 10% of allowables.
Mike McCann
MMC Engineering
140Airpower
Automotive
Mike, it's hard to understand plug fouling. I haven't encountered that since they got rid of lead, but I know that oil fouls plugs, also an ultra-rich mixture might do it. Don't know of anything else. Passing smog is a sure sign of an engine that's running right.
msquared48
Structural
I just put 39.1 gallons of 89 octane in the tank. We'll see how it runs... $160.00!
Mike McCann
MMC Engineering
Mike McCann
MMC Engineering
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