Can you tldr plsOriginally Posted by eekayfo
i realise this is an old thread but its new years day, im not doing shit all. and its relivant information to those with sub 2l engines
everyone is saying go final drive make the car lighter more displacement ect ect all i see a final drive doing is letting the engine rev up to its powerband faster. obviously a lighter car will help acceleration in any situation and more displacement, well.....
as i see it with a set displacement NA, theres a limit to the peak torque that you will see. dosent matter how high or where you rev it to see that number. with horsepower being a measurement of work. i.e x mass moved x distance in x time... it makes sense design the engine to rev up and make peak torque up high to see good hp/kw numbers. but your still limited to that peak torque number unless you strap on a blower or nos, race fuel and 16to1 comp ect ect.
in order to get close to that peak number, you need to design an engines internal geometry to work best in a desired rpm range(rod/stroke bore/stroke ratios), you allso need to design cams, intake and exhaust manifolds and also GEARING to suit the engine and its desired rpm range. ideal compression is derived from cam profiles, dynamic compression and quench and head design to ward off detonation on specified octane fuel. once all these have been designed, built tuned and tweaked to perfection will you be getting close to the maximum torque able to be produced from that set displacement. AT THE RPM IT HAS BEEN OPTIMIZED FOR.
so back to the op's question, how to increase low end/rpm torque theres a few things he can do. redesign the entire engine for a lower rpm. not cheap redesign the Bolton's, manifolds cams gearing for the lower rpm. cheaper increase displacement well this is a sure fire way to raise that peak torque, the larger engines are often designed from the factory for lower power bands as the heavier internals are harder to reliably rev in a factory engine. but if designing ones own, power can be moved anywhere. \
in the end, where you make the power dosent matter, high torque (dont think hp) numbers and a flat curve are desired. optimize gearing to suit the power band. take my b16 for example. i would regulary rev to 5k in second to got to 60km when i swapped in a b20 with the same gearing, i would do the same in 3rd and only rev to 3500rpm. both in probably a similar time and fuel use. cruising along in 5th can accelerate up hills and has that instant acceleration when the pedal is pressed. but lacks that vtec high revving ability of the b16 without substantial investment.
i guess its all a comprimise and you have to decide what ones you want to make.
i hope ive educated someone and not pissed off others by grave digging and posting misinformation/.;.
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