owen_the_soyboy

shortening the GEARS allows you greater TORQUE at a lower SPEED.

if you plot Torque vs. mph in order to compare two different final drive gears, you will undertsand in a second.

this in essence gives you more torque, but it is really "more torque at the same mph in the same gear" because youve lowered your highest mph thus you need to squeeze the torqu curve in between less mph... = more tq/mph.

Torque is mostly a function of displacement.... generally speaking... add displacement is adding torque. but shortening gears gives you more of your torque sooner... the torque multiplication from running shorter gearing is incredible to feel firsthand.

glagola1

Torque is rotational force. I don't care where you measure it. You could measure it at the wheels or at the flywheel. If you measure at the wheels, gearing will play a roll in masking that real torque that the engine is making. For the sake of this discussion, let's eliminate the gear box so we can have a more simple modle.

Horse power is a derivative of torque and rpm. They are mathmatically linked. The formula for the two is: HP = Torque x rpm / 5252.
For example if your engine makes 100ft lbs of torque at 3000 rpm it will make 57.12 hp at 3000 rpm. That's why the s2000 makes so much hp. It revs really high and makes decent torque at redline.

Now, let's discuss factors of making low rpm torque which is commonly how it is viewed. It's kinda funny that people are like the S2000 makes no torque but it makes tons more torque than most cars it's compared to at high rpms. Those cars that are considered torquey run out of breath at 6000 rpms. Anyway, here are a few engine design criteria for making low rpm torque:

1) Stroke. A long stroke makes power because the leverage the piston puts on the crankshaft is high. It's also a limiting factor in redline.
2) Head design and intake runner length and cross sectional area. Both of these work together to create velocity in the intake charge. Since the motor is not spinning super quick at low rpm, there needs to be a good velocity to the air going into the motor. That's why the torquey motors have long skinny runners and the high HP motors like the F20C have fat short runners.

When people say displacement makes torque that's pretty much the same as saying engines make power. Duh. The bigger the engine, the more power (torque) it will make. Displacement does nothing by it self to dictate the power delivery characterstics of the motor and since the power delivery characteristic is what we're talking about, it does not pertain to this question.

KF_S2000

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by glagola1 &raquo;</TD></TR><TR><TD CLASS="quote">
2) Head design and intake runner length and cross sectional area. Both of these work together to create velocity in the intake charge. Since the motor is not spinning super quick at low rpm, there needs to be a good velocity to the air going into the motor. That's why the torquey motors have long skinny runners and the high HP motors like the F20C have fat short runners.</TD></TR></TABLE>

I agree with everything you are saying here, but the factors you mention don't really get to the point of the post which is what determines torque. The factors you are mentioning above actually define low RPM torque creation vs. high RPM torque creation.

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by glagola1 &raquo;</TD></TR><TR><TD CLASS="quote">
When people say displacement makes torque that's pretty much the same as saying engines make power. Duh. The bigger the engine, the more power (torque) it will make. Displacement does nothing by it self to dictate the power delivery characterstics of the motor and since the power delivery characteristic is what we're talking about, it does not pertain to this question.</TD></TR></TABLE>

I said this, but I don't see the correlation you are making. If you want to get technical, engines don't make power, they simply take the energy release from burning of oxygen and fuel and turn that into mechanical work. But I digress...

You are right, displacement does nothing by itself to dictate the power delivery CHARACTERISTICS of an engine. I was simply siting displacement as an answer to the original question posed by the thread creator. There are many things that determine torque, but the biggest factor is displacement.

glagola1

Well, I was simply writting under the guise that when people say a motor is torquey, they really mean that the motor creates power in the lower rpms. I mean, people could say that the S2000 was torquey and it would be true. What other motor makes torque at 9000 rpms?

owen_the_soyboy

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by glagola1 &raquo;</TD></TR><TR><TD CLASS="quote">What other motor makes torque at 9000 rpms? </TD></TR></TABLE>every motor, once.

LSTEG96

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by revhi &raquo;</TD></TR><TR><TD CLASS="quote">Let me use the Evo as an example, even though its turbo. It has a simliar engine size and displacement, but its torque numbers are 286 and 276 hp. A turbo S with 276 hp would not have 286 pound feet of torque.</TD></TR></TABLE>

bad example...wrong too. a turbo is like increasing displacement...so turbo cars should not be considered in this argument...as they are like having bigger engine...which as stated above will make more torque.

torque is actually what u feel, horsepower is a mythical creature we made up.... it is the ability to produce torque at certain rpms, and the rate at which it is produced.

Francesco

and you also have to consider compression. turbo cars run low compression, we run higher compression.

papa5murf

turbo/superchargers and stuff like that.. is like adding displacement......

however... you look at an s2000 that has a turbo.... does it have .. 400rwhp and then 400lb/tq? no... absolutly not.. it usually has 400rwhp and 280lb/tq.... why is this?? cause of the gears and our cars are high reving......

i can pretty much guarantee.. if we changed our gearing and made our cars a low revving car... we could achive those numbers of 400rwhp and 400lb/tq.... but then again.. who would want to do that and get rid of our high revving capabilities.... also by lowering the changing our gears and making it a low reving car will also decrese our hp number because we won't have a long gear to allow the hp to develop....

like i've said before... gearing does a lot....

jgill17

Displacement and stroke/bore ratio determine your engines torque. Gearing is what makes torque usable.

ex. hook a John deer up to a tree and pull it over. Now take your Supra that is making 750hp 500ft/lb and try to do the same.

LSTEG96

maybe its just me...but im pretty sure every single word u have said about gearing is wrong...

gearing will affect the power out put the ground... yes.

but, that power to the ground will always be a ratio of the power put out by the engine...so no matter what u do, your not going to get much more to the ground

also, lower the rev limiter? have u read this thread? torque is a function of HP, which is linear to RPM... lowering the rev limiter will literally do nothing...except make your car slow, and put a cap on all that power up top (hp that is, not torque)

longer stroke, turbo, displacement... only ways to get torque. think of a big block...that stroke has got to be like 12123897mm, where hondas are like what? 89-95mm? also, cars that produce big torque are terribly inefficient when it comes to hp/L... s2k's are 120hp/L and a 5.0 mustang motor is like 52hp/L...but it makes a hell of a lot of torque, FOR HOW MUCH HP it has.... i dunno

papa5murf

output to the ground is what you want... who cares about that whe engine makes... it's what gets to the ground that moves the car....

you need to read my posts more carefully... i've given many differnt examples... examples of motors that have the same hp, but differnt gearing, examples of cars that have same tq numbers but differnt hp... yada yada yada.....

gearing and revs are different....

LSTEG96

this is true...u could have an engine rated at 50 ft lbs and have 108237 ft lbs to the ground...but it would only go .0000001 mph... ull sacrifice many things when you mess with the gearing (after a certain point of course). the best method is to look for more hp going into the tranny...

owen_the_soyboy

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by LSTEG96 &raquo;</TD></TR><TR><TD CLASS="quote">
but, that power to the ground will always be a ratio of the power put out by the engine...so no matter what u do, your not going to get much more to the ground
</TD></TR></TABLE> just be sure you understand that shorter gearing on the same motor will get you more power to the ground... well, to be correct, you get more of it at the same mph as a stock setup... so, you are getting more... the concept just has to be defined precisely.

papa5murf

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by LSTEG96 &raquo;</TD></TR><TR><TD CLASS="quote">this is true...u could have an engine rated at 50 ft lbs and have 108237 ft lbs to the ground...but it would only go .0000001 mph... ull sacrifice many things when you mess with the gearing (after a certain point of course). the best method is to look for more hp going into the tranny... </TD></TR></TABLE>

well think about s2000's.. i've stated this before......

what do us guys that own s2000's do?? we change our gears.... stock comes with a 4.10 gear ratio... and we change tit o 4.44, 4.57 and 4.77's... ... why do we do this?? obvioulsy..... .faster acceleration.... torque is what makes you move.... so the more torque, hypothetically the faster acceleration you have.....

gears do a lot more then you guys think.....

so everything that i've said about gears is correct...

.Chris.

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by 03s2kblue &raquo;</TD></TR><TR><TD CLASS="quote">

well think about s2000's.. i've stated this before......

what do us guys that own s2000's do?? we change our gears.... stock comes with a 4.10 gear ratio... and we change tit o 4.44, 4.57 and 4.77's... ... why do we do this?? obvioulsy..... .faster acceleration.... torque is what makes you move.... so the more torque, hypothetically the faster acceleration you have.....

gears do a lot more then you guys think.....

so everything that i've said about gears is correct... </TD></TR></TABLE>

Yes, but I think they want an explanation for crank TQ. What makes an engine a torque beast and what makes an engine a high HP screamer.

There are a lot of factors, R/S ratio, Bore/Stroke Ratio, Cam and head design etc.

SuzukaBlueAP2

Just my .02 about the relation of the transmission and the engine torque...

If your engine produces max torque at 6000 rpm, then the transmission is going to be geared to keep the vehicle in the part of the powerband where most of the torque and horsepower are generated. So, it would be my understanding that without proper gearing, regardless of how much or how little hp and tq and engine produces, the vehicle's engine would not be as useful as it should be and be capable of maximum power.

any who...just wanted to toss that into the equation.

papa5murf

^ thank you... i couldn't have explained it better myself.. hahahaha.. i've been stressing the gears this whole time.. and yet no one wishes to listen....

maybe someone will finally listen...