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ORIGINAL: Kolni

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ORIGINAL: biopic

Ever read about putting acetone (paint thinner)in your gas? Goggle it and find out. They state that acetone added to your fuel will help it atomizebetter andin turn helps it to completely burn resulting in better fuel combustion. I have used it in the Harley, Duramax and small engines around the house. I gained 2 mpg in the truck and can notice the running difference in the Harley. I add 2 oz per 10 gallon. It makes the molecules of the fuel slippery.

Then why don't the gas companies already do this?

Seriously.

And what do you think is coming out of your tail pipe after acetone is burned. Not 100% combustion -- pollution is nasty.

 

Lost1,
the compression ratio does not change based on adding air into the cylinders under pressure.It is a function of volume in the cylinder and the air/fuel mixture being squeezed (compressed) as the piston moves to top dead center.
A turbo or supercharger will push more fuel/air into a cylinder but will not change the compression ratio. In fact tubo and or supercharged engines typically have lower compression ratios than high performance engines without them. (except for what Banks Engineering does with diesels- but that's a whole 'nother approach.

 

Sorry, but I must disagree.
If you've ever built a supercharged, turbocharged or otherwise pressure-assisted engine you know that an engine has a static compression ratio, which is the fixed C/R of the engine on the stand at one atmosphere (which appears to be what you are referring to in your post) and a final C/R, which will be the maximum C/R of the engine at full boost under "X" atmospheres. The compression ratio varies depending on the degree of boost at any given time.
The formula we use to determine final compresson ratio (FCR) is:
[(boost psi/14.7) + 1] x static C/R where boost is the max boost pressure and 14.7 = 1 atmosphere at sea level. To correct for changes in altitude another formula is used:
FCR - [(altitude/1000) x .02] = corrected final compression ratio.

The final C/R of the engine must be known before building the engine as it will dictate what components must be used in engine buildup, supercharger gearing and drive ratios, what fuel will be required, and other such essentials.

Not being argumentative but I do this for a living; if you doubt what I've said I'm sure you can research this further at performance engine building and/or supercharger/turbocharger websites.

 

...The Lost1 is making solid points.

For years I was an Electronics Technician for Ford Motor Company in Light Duty Truck and SVO.
We also had the Fuel Systems and Calibration.

There's a lot more to this than "static" compression and intake/exhaust.

On many of the Hot engine designs compression isn't as high as you would imagine.
One of the major considerations is longevity, even in race engines.

Build a wild internal combustion enginewith high revs, you're not looking at MPG but what spins it furiously and true.
Ambient factors are always in play, on race engines and stock Harley engines.

What happens when you don't change the compression on a newer H-D engine but instead...
You alter the intake and exhaust, and all timing circuits.
On the intake you use designs like the Yost Power rod, etc.
Your exhaust is tuned...
Now she's spinning furiously, with the same compression...
This is where you start testing with fuel additives...This is where increments count.

 

please for the love of god......tell me in idiot( my ) terms, if i change my intake to SE and run VH shortshots, what octane is best? i've been using 89 because it's hot here (86-93) and it seems to run a little cooler.

 

If it doesn't ping use the 89.
If it does use 91 or 93...

 

Good post, wisemx.
I agree, and we haven't even begun to touch on dynamic compression ratio, valve timing, etc. and all the other engineering aspects of power, pressure, C/R, and so on.
Just trying to keep it light without going off on too many tightly-focused tangents...

 

It looks like this product would meet the BountyHunter endorsement criteria. [8D]

 

I'm not an expert, but many of the head porters I've read articles from claim to be; and your claims would be countered by their teachings.

Instead of big oversized valves, they now use smaller valves just large enough to feed the motor, with the aim of keeping the incoming velocity of the charge up. They claim that the momentum of the incoming charge can create a slight overpressure charge in the cylinder before the intake valve closes....leaving a slightly higher than atmospheric pressure level to combust.

 

...True bro, it's far too complicated to cover every aspect, especially good numbers from advanced timing alone.
Yeah, you guys trying to boost the fuel for MPG alone....Youmay be able to do that simply with advanced ignition timing.

It's a lot like Tennis....The ball is flying at your racket, smack it hard up front, wham! [8D]