crazy idea
Thread Starter
|
Posting Guru
Joined: Apr 2002
Posts: 1,187
Likes: 0
From: CT
crazy idea
I'm trying to make a simple dyno and am stumped on the equations to get HP, or watts if it is easier, by the data i can get. I'm going to have a laptop hooked up to the tach lead of my engine to pick up the pulses and turn that into rpm. That using the weight of the vehicle, final gear ratio, tire size and acceleration.
Am I crazy (sure i am) but, can anyone give me some help?
Am I crazy (sure i am) but, can anyone give me some help?
Laughing Gas
Joined: Nov 2001
Posts: 807
Likes: 1
From: -
Senior User
Joined: Nov 2002
Posts: 286
Likes: 0
From: Homestead, FL
crazy idea
Hi-
Dyno's don't measure HP they measure torque. Then horsepower is calculated as a function of torque at a given RPM.
Like this:
torque x RPM
_________________ = HP
5252 (constant)
Which leads me to an old question. 2 engines are being tested. Engine1 turns 1000 rpm's and produces 1000 ft/lbs. of torque. Engine2 is turning 10,000 rpm's and is making 100 ft/lbs. of torque. Which engine produces more horsepower?
They're making exactly the same HP
Dyno's don't measure HP they measure torque. Then horsepower is calculated as a function of torque at a given RPM.
Like this:
torque x RPM
_________________ = HP
5252 (constant)
Which leads me to an old question. 2 engines are being tested. Engine1 turns 1000 rpm's and produces 1000 ft/lbs. of torque. Engine2 is turning 10,000 rpm's and is making 100 ft/lbs. of torque. Which engine produces more horsepower?
They're making exactly the same HP
Thread Starter
|
Posting Guru
Joined: Apr 2002
Posts: 1,187
Likes: 0
From: CT
crazy idea
I know how to get horsepower from torque, I'm doing this for a computer technology class. And i need to get torque bfore i can even het the hp.
Say the vehicle weighs 4000lb.
The transmission has a gear ratio of 3:1
The rear end ratio is 3:1
The tires are 32" tall (not factoring in tire deflection)
Hooking up a lead from the tach to the serial port of a laptop i can pick up the pulses of the coil, devide by the # of cyls and get a rudimentary tach.
Say i do a test run, from 1000rpm in second gear (3:1) to 4000rpm. From 0 seconds a program starts a log.
time - rpm - after gearing
0 sec - 1000rpm - 111.11rpm
.5 sec - 1100rpm - 122.22rpm
1 sec - 1200rpm - 133.33rpm
1.5 sec - 1300rpm - 144.44rpm
etc......to 4000rpm - 444.44rpm
for ever .5 second the engine is increasing 100rpm
and for every .5 sec the tires gain 11.11rpm
i'm stuck on how to put everything togeather.
Say the vehicle weighs 4000lb.
The transmission has a gear ratio of 3:1
The rear end ratio is 3:1
The tires are 32" tall (not factoring in tire deflection)
Hooking up a lead from the tach to the serial port of a laptop i can pick up the pulses of the coil, devide by the # of cyls and get a rudimentary tach.
Say i do a test run, from 1000rpm in second gear (3:1) to 4000rpm. From 0 seconds a program starts a log.
time - rpm - after gearing
0 sec - 1000rpm - 111.11rpm
.5 sec - 1100rpm - 122.22rpm
1 sec - 1200rpm - 133.33rpm
1.5 sec - 1300rpm - 144.44rpm
etc......to 4000rpm - 444.44rpm
for ever .5 second the engine is increasing 100rpm
and for every .5 sec the tires gain 11.11rpm
i'm stuck on how to put everything togeather.
Elder User
Joined: Oct 2002
Posts: 834
Likes: 0
From: Germany
crazy idea
[QUOTE]Originally posted by pbrstreetg
[B]Hi-
Dyno's don't measure HP they measure torque. Then horsepower is calculated as a function of torque at a given RPM.
Like this:
torque x RPM
_________________ = HP
5252 (constant)
pbrstreetg, if it so than a 6.9 ltr Diesel must have approx. 226 hp.
330 x 3600
___________ = hp
5252
Could it be????
Jens
[B]Hi-
Dyno's don't measure HP they measure torque. Then horsepower is calculated as a function of torque at a given RPM.
Like this:
torque x RPM
_________________ = HP
5252 (constant)
pbrstreetg, if it so than a 6.9 ltr Diesel must have approx. 226 hp.
330 x 3600
___________ = hp
5252
Could it be????
Jens
Thread
Thread Starter
Forum
Replies
Last Post
