All Motor B20Vtec

[spetz]

Actually I asked because I wanted the opinion of someone who has a high comp NA motor (ie, the pros/cons for your application).
I've read articles about it and to be honest not quite sure which parts to believe, as I see a lot of people now use E85 for high powered cars, but just a few years ago anything with ethanol seemed like the worst thing on earth

[gbpracing]

Actually I asked because I wanted the opinion of someone who has a high comp NA motor (ie, the pros/cons for your application).
I've read articles about it and to be honest not quite sure which parts to believe, as I see a lot of people now use E85 for high powered cars, but just a few years ago anything with ethanol seemed like the worst thing on earth

Use Of E85
While is copes quite well with the compression ratio, there appears to be no other benefit, unless you had a turbo engine.
However on the down side, it uses a massive amount of fuel compared to conventional fuels, this means larger fuel lines, pressure reg etc. The blow by has a strong tendency to dilute the engine oil. The fuel being an alcohol type is hygroscopic in that it absorbs moisture. You can end up with a catch can that distils its own alcohol in it. Also like Methanol the car can be hard to start cold. While V8 tourers use the fuel they do so for more political reasons.
Cheers

[spetz]

Thanks for that.
Does this mean that because it copes well with high compression, that you can have a more powerful engine if built with E85 in mind?
Otherwise it seems like it is no good

[gbpracing]

Thanks for that.
Does this mean that because it copes well with high compression, that you can have a more powerful engine if built with E85 in mind?
Otherwise it seems like it is no good

Simply put, I would be using about 30% more fuel to achieve same power and my 12:6:1 is not really thought of as high comp when compared to other race engines, when I speak of high compression engines I'm talking 13:1 up to 16:1 to benefit use of E85 OR Turbo where cooler air/fuel charge is created from use of E85.
So no I would not make anymore power using the same engine set up with E85 and yes for my application it would be a waste of time.
I know a guy that has built much the same ALL MOTOR engine combo as I have B20 block and B16 head , higher comp 13:1 using E85 and he has less power than I do ! Now there are many other build factors that need to be considered, such as how much head work was done, cam shafts used lift duration, I may have other mods that have been done to mine that he may not have done to his and so on..The list could as long as your arm !

[Dart]

Have you put a compression tester onto your engine ( screws into spark plug thread) just curious . I would like to compare the reading with my built engine.

[gbpracing]

Have you put a compression tester onto your engine ( screws into spark plug thread) just curious . I would like to compare the reading with my built engine.

I really dont see the point as my engine build is substantially modified and is one of a kind as most engine builds are. Can never really compare one to another..as there will always be something unique and even subtle things make a differance.

[Touge Tom]

yeah, cam duration also changes compression ratio. considering true compression begins when the intake valve closes and the piston has already risen up the bore slightly. then there's rod ratio and how much CC's the combustion chamber has? take mine for example, iv'e got a standard p72 head, 13.5:1 static comp, 1.58:1 rod ratio and a 250 dur cam's @ 1mm lift. the actual cranking compression is only 11.5:1 or so.

[Dart]

yeah, cam duration also changes compression ratio. considering true compression begins when the intake valve closes and the piston has already risen up the bore slightly. then there's rod ratio and how much CC's the combustion chamber has? take mine for example, iv'e got a standard p72 head, 13.5:1 static comp, 1.58:1 rod ratio and a 250 dur cam's @ 1mm lift. the actual cranking compression is only 11.5:1 or so.

The last two responses is why I asked the question. I know there is all the above listed variables , and I was curious to see in this case what all those variables added up to.

[gbpracing]

The last two responses is why I asked the question. I know there is all the above listed variables , and I was curious to see in this case what all those variables added up to.

This is a dead end discussion,we have given you enough info to help you realise that engine builds are an individual and unique to each project. The outcome is dependent on the detail, expertise, experience and money !