3 years 4 me.

[vlad01]

normally engines are over square by 10mm from what I have noticed. so that mean bore 10mm bigger than the stroke. Must be a sweet spot in terms of balance between the 2 and least compromises

[Jayme]

At car forums I always like to join in the arguments where people say that a long stroke engine gives more torque than a short stroke engine of the same swept volume because they have greater leverage courtesy of the longer crank throws. Assuming volumetric efficiency is the same in both cases. They never seem to get the idea that the greater leverage is countered by the same psi on the piston working on proportionally less si.

can you elaborate for the ignorant who dont know what si is? I cant get my head around your last sentence

[Circlotron]

Taking a bit of artistic license perhaps....

psi - pounds per square inch (of combustion pressure).
si - square inches (of piston area).

"si" is probably not "correct" but was meant to be understood because of "psi" written just before it.
----------------
The idea is that if you have an engine with twice the stroke and half the piston area of another engine of exactly the same cubic inches, the greater leverage of twice-as-long-stroke crank will indeed try and make double the torque, but seeing it's piston has only half the surface area of the short stroke engine the long stroke crank only gets pushed half as hard. 2 x 0.5 is the same as 1 x 1.

[vlad01]

Maybe you should of written it like this? inch²

So, is this correct what I assume? less rotational mass= better with shorter stoke, and would there be less friction coz of the less distanced moved? or is that outweighed by more friction surface area with larger pistons?

I also recall having a convo about which was more thermo efficient with someone before, not sure on that one.

[Holden202T]

there was actually an interesting article in one of the last few street machines about small motor's v's strokers!

[vlad01]

What I have found with small bore long stoke engines is the bores, seem to wear out faster. I am not sure if thats coz of it, or unrelated issues?

the ford 4L engines always seem to wear their bores out by 200k, get a couple mm for side clearance in some cases. they have 99mm stroke 93mm bore

seen this on a lot of old British engines where they commonly have huge stroke, small bores. Some jap 4cyl too.

[The1]

I came over here for a number of reasons, but mainly because ppl are decent on here and get on with what we do and talk about.

[vlad01]

I noticed these qualities later after joining, makes me realize there are decent groups of people out there And that people can get along.

[delcowizzid]

yeah i think we have had 2 bad apples over all the years banned its good having no personal attacks and threats LOL

[Holden202T]

agreed, main thing i like about this forum is people just share their shit, none of this "my secret tune that no one can see!" everything i do is posted online in the custom tunes sections and happy to help out as others have done for me!

I know well enough that any tune i do is never going to be perfect in another car so theres no reason not to share it, the recipient will still have to do their own tuning to get the most from it but the ground work is there for a base tune.

And the rest, well i put as much online as i know to be true from my personal experience because alot of what i've done there was no answer for, other than "don't bother" or "it wont work" .... well it does and now the info is online so maybe the next person will be able to do it a bit easier and the world is a better place from it!

I'm not out to destroy tuning shops, because you pay money for a tune done by an experienced operator, but i also believe there is far too many money hungry tuners out there with NFI and so im happy to help out the home tuners to avoid getting ripped for something they can do just as well themselves at home!

the efi world was once a "black art" that you always got scared about taking your car in for $$$$$$$ to fix an engine light ..... thats fast becoming an open book and the world needs it