I was lookin at a viper V-10 and it only produes 450 hp and 490 ft lbs of torque. How is it so fast if it doesnt doesnt even have that much horsepower? I want to make a fast truck but it seems like i need some more info. hey jwtaylor i was wondering if you had an aim screen name because i think that you could lead me in the best direction during this process. Well thnx for the help yall have already given before and thnx for all the advice.

 

dude that is a lot of power but it can have more. the torque is huge. the viper venoms make 750 horses and that is what i want

 

big tires for traction, good aerodynamics, a six speed, gearing.

 

...and the most important thing that nobody here has going for them: Lightweight!

Guess why those Mazda Rx-7's are so fast? That rotary engine can't put 200 HP to the ground without nitrous, even when turbocharged, but it will blow the doors off of our trucks because it weighs around 2,500 lbs. with a fat driver, soaking wet.

It's not the power that counts, it's the power and the weight that it has to push, as well as the gearing, traction, and etc. that were mentioned above. TK

 

hazardousdrew

I appreciate your comment but I am not so sure I would be the person you should talk with. However, if there is something I know that can help you then just ask. This site is a great source of information, but I would be more than happy to try and answer any questions you have and/or have yet to be answered. If I don't know the answer I will do my best to find out. Just e-mail me, go to the front of forum "performance and general engine building" you should find my name in blue, under thread starter or last post, click on it, then click on send this user an email. Email me, I will give you my "IM" name and we will determine a time we can throw ideas back and forth. Later

 

Power to weight ratio teamed up with aerodynamics, traction, gearing
and driver skills can make the viper one fast SOB.

That torque rating is what gets it moving so fast.

 

The 2001 Viper gts weighs 3450. My truck weighs 3850. With slicks I am sure my truck would hit mid 13s with out of the box tuning that it has right now. I am not making 450HP. 450HP will get you moving faster than you think. Many bracket cars in the 12s aren't making 450HP. Most people that think they have 450HP are making way less.

 

Torque

 

I don't necessarily agree even though you are right. <--- (Mark that down as the stupidest thing you have heard all day.) Torque at the flywheel doesn't get you moving. Its torque at the tire that gets you going. But that being said since the viper and other sports cars are similarly geared the large torque output does help the viper. A 450HP 6 banger (optimally geared) can do just as good as a 450HP V10.

 

plus tha 6 would be lighter so that is even better lol

 

This is true. Its the reliability factor of the smaller engine that becomes an issue.

 

so if i hopped up a six for my falcon, plopped in a t-5, and got some sticky tires, would that make me faster?my 2300 pund lcon w/300 horse has a power/weight ratio of 7.6- the same as a viper, but I could gear the falcon right, be faster and still hit 150, plus the falcon has something that the viper doesn't-stealth, so why dont we all run out and buy falcons?

 

re:Torque at the flywheel doesn't get you moving. Its torque at the tire that gets you going.
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Ok, this is like saying fish don't swim...they merely fly in a thicker atomosphere.....heheh

How the torque gets transferred from the flywheel to the rear tires and how the chassis/suspension interprets that power transfer, taking into consideration the coefficient of friction of the driving surface...will have a direct effect on how the vehicle will accelerate...

Where the torque happens is the important factor.....a V10 will always give you usable torque whereas the 6 will wind up all day to get you there...regardless of the same 450hp....of course with driveability/reliability
being another side effect...

One thing is to make power and torque......it is another to lay it down right...
I know of mustangs running 400hp that run in the high 11's and their chassis, suspensions are tweaked just right and these aren't even drag cars!!! they are open track cars!!!

 

I have some new insight to the torque issue:

remember from physics, work is defined as (force) x (distance). Torque is measured in ft*lbs, therefore torque is the engine's ability to do work. Imagine if you could graph the torque output of a vehicle vs. time as it accelerates from a stop. If you could add up the area underneath the torque curve (the practical meaning of taking the integral of the line) from the time the vehicle started to the time you let off the pedal, then divide that number by the weight of the vehicle, and you would have calculated the acceleration of the vehicle.

1) work = force * distance
2) power = work / time

substitute 1) into eq. 2), and you have:

power = (force * distance) / time
from our knowledge of torque: power = torque / time

time comes from the rotational velocity of the engine, i.e. RPM
This is why you se the formula HP= TQ/5225, because power is dependant on engine speed. In fact, a dynomometer cannot directly measure power, the only measurement that is taken is a torque reading, and the HP curve is calculated.

back to torque and speed.

the torque that is finally applied to the axles, after all drivetrain losses, is transferred to the pavement as a force, because the torque in the axles must be applied a distance equal to the radius of the tire. Some internet calculators I've seen have actually described this as "drive force". Smaller tires transfer more force to the pavement with the same torque than do larger tires.

Thence, acceleration is (from Newton's second law): a = F /m, where F= drive force, as defined above, and m = mass of the vehicle. A quick look at the formula shows how a decrease in "m" makes a get larger. Larger acceleration puts stupid grins on your face, and more blue lights in rear view mirror.

The gearing has a profound impact on all of this. Gears multiply the torque of the engine, and a well-designed geartrain should place the engine in its most usable torque range.

The Viper will **** all over a similarly POWERED and wieghted V6, not only because of it's 6-speed transmission and dump-truck differential ratio, but because the Torque curve for that engine is very broad, quickly making over 300 ft*lbs just above idle. The difference is a V6 will have to wind up to 6,000 RPM to make that kind of power, as Capone mentioned. Then unless it was so closely geared that it could only drop 500 RPM between shifts, the upshift knocks the little V6 down to a speed where it has very little torque, and the V10 is still screaming with over 400 ft*lbs on command.

BTW, my favorite racing class is NHRA Pro-Stock. Gotta love the no-forced-induction, no-nitrous, 1 carburetor door-slammers running 6.8's. 13,000 RPM V8's that make around 1,300 HP. Can you imagine the dyno curve for that thing? I always use that as my selling point over why these import guys are wasting their time. Big engines rule. TK

 

Smaller engnies with equivalent power can have a broader torque curve. Compare a 600HP 460 to a 600HP catipillar semi engine. The semi engine has far more torque than the 460 but has a very limited RPM range. This is a drastic comparison but it still works. The 600HP 460 geared and stalled optimally can move just as much weight just as fast. The lack of feasibility makes the choice a no brainer.

And yes muscletruck. If you souped up your falcon's 6 banger you could run on the straights with the viper. Better stay out of the curves!

In order for the big cat to get the truck 80MPH it needs a much higher gear in the rear. The 460 would need a much lower gear to move the same speed. This is why we use the measure of horsepower. The same torque is still being applied to the axle. Do the math.

Now I am not saying that we should all be running small cube engines to go racing but tell a buick grand national owner making 600HP with his little 3.8L that he can't keep up with a monte carlo running a 600HP 454. Sorry to use GM here but ford never got into the idea of cramming tons of air down a small less durable engine.

We often shoot for big torque in our pickups as we do not like running high stall converters 5.13 gears and turning 4,500rpm down the interstate while we are towing the big boat and trying to hear the radio.