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Old 12-12-2012, 04:55 PM
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Originally Posted by Yachtsman View Post
Quite a few other people, want to want to be driving things apart from electric cars when oil runs out. All the oil companies are putting lots of money into 'Alternative fuels'. what most people forget is that I.C. engines first of all ran on ethanol. Historically Gasoline is the Alternative, even all Henry Ford's Cars until the model A ran on undiluted Moonshine, had Oil not been found in Pennsylvania they still would. Gasoline for cars is no longer a few cents a gallon. Research groups all over the States are looking at liquid fuels that can be used in car engines without much expensive modification. Modern cars have injection systems and an ECU that can adjust the timing widely the new V6 Ecoboost Ford engine should do good mileage on E85 while doing good power.
Isnt the ecoboost e85 compliant in the uk it is in the states and does have wide band and full control of timing and fuel. If you put e85 in it you will have the best mpg the engine will give with e85. Not that it will make more power with e85.

Just rasing compression will not net any power gains. But if you rasie all factors at once you should be able to net almost 100hp per point of compression. More compression will allow you to run more cam once you match the cam up to the compression you get more rpm and more hp or more importantly you get volumetric effecency at a high rpm for a much higher hp gain than at stock rpm near 100 percent ve point. Now as you go up in compression the laws of physics kick in and you get demenished returns the higher you go.

This is very clear if you take a 7:1 big block 454 late 90s pos motor and bounce it up to 10:1 and make cam changes needed to support that you will have gained almost 250hp with that compression upgrade. But everything else needs to lne up for it to work.

Now i have a monkey wrench to toss into your project sorry to say but more compression means more gas as well. More air more fuel no way around it. Even a small change in compression to efi engines can result in the need for a tune and injector upgrades. Add cam and free flowing intake/exhuast and you will get twice the power and use twice the fuel or a 1/4 more power and use 1/4 more fuel. No way around that either. Adding compression increases effecientcy but does not increase mpg. Because of idle time and normal driving gearing needs you will burn more gas for sure.

We all have senn the power levels of american muscle cars many times the big engine was still in the car but had no power cause it had no compression retuning the big v8s from 9:1 to 8:1 or even 7:1 in some cases made the cars get much better milage but was harsh on hp. It took years to get economy back and still make good power. Now they use gears and well controlled fuel system to keep the mpg in check. Put a LS motor with a carb and open exhuast ina car that ways 4000 lbs plus and has a powerglide 2 speed and it will get 8 mpg if your lucky.

In most cases with modern cars the engines are simply smaller and make more power with smaller bores. The efi used to make 300 hp has not gotten that much better than a well tuned carbed engine. Its really a small percent better fuel. Now alot of cars back in the day just ran pig rich so that is one thing that was corrected and shows up in results but really not that much.

Last edited by hcompton; 12-12-2012 at 05:21 PM.
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