ok first the parameters
i was on a mustang dyno , bar 30.20 - humidty 40% -
temp 60 degrees F , altitude 1500 ft , correction factor .94
air/fuel ratio stayed 12.6 - 13.0 thruout run
timing 32.1 degrees in chip , 6 initial

graph starts at 3100 rpm with 273 ft lb and climbs to
421 ft lb at 4100 rpm . over 390 ft lb from 3400 - 4700 rpm
i'm happy with that

horsepower starts at 133 hp at 3100 rpm and climbs to
236 at 4900 .
205 at 4100
216 at 4400
226 at 4600
236 at 4900
221 at 5100
200 at 5300
how can a motor have 400 plus torque at 4000 rpm
and only have 235 hp . i know these are torque motors
but if you have torque at an elevated rpm i would think
you would have some hp because hp is a math formula
of torque x rpm divided by 5200.. anyone have an idea

mike

 

Doesn't make any sense to me, the formula I have is:

Hp = (rpm x torque)/5252

Using that math I get

328.66 = (4100 x 421)/5252

Not 205hp???

Guess a mustang dyno is as worthless as it's name would imply, hehe...

 

It's because of the torque converter multiplying torque. See it all the time. Until the converter gets above its stall speed you have to discount any readings as far as what the engine really puts out.

Trying to dyno a race car with a "6000" converter is just about useless.

 

that might make sense except i have a oem gmc typhoon
torque converter and datamaster shows lock up at 2100 -
2200 rpm and at that point i have 273 rwtq and it climbs
up from there until it peaks at 4100 rpm .
any other ideas ???

mike

 

Mustang Dynos are just weird like that. You can't directly compare the numbers to a dynojet, or anything else that makes sense. I forget exactly why teh numbers make no sense, but i rememeber reading an article about that at one point.

 

i am more confused now
i looked a graph from a 90 vette
i took there and got 297 rwhp - 360 rwtq
with normal looking graphs

any ideas on a parameter that could be entered
wrong ?

mike

 

Are you absolutely sure it locked up?

 

Even if it didn't lock up and was something to do with torque multiplication, should not the HP numbers be inflated highly as well, as HP is a function of torque?

It's like the calculations it used to figure hp were wrong or something...

 

Like ED said..Those dynos always seem to come up with weird numbers. Try and find a Dynojet model, if that torque number is right you should be well over 300 at the wheels.

 

i spoke with dave forbes at mustang dyne
the manufacture of the dyno . i faxed him
my dyno sheets and he noticed my graph
for the horsepower and the graph for the
air/fuel ratio meter both have the same peaks
and valleys thruout the pulls , because those
two pieces of equipment are not related he
believes there was EMI static causing the
horsepower graph to be incorrect . there was
not the same peaks on the torque curve so
he said those numbers should be correct . i would be
thrilled for that to be true but my injector duty %
is mainly in the upper 80's - 90 % , on the vette
that i dynoed there the injector duty was mid
upper 90's % . any thoughts on what the stock
injectors duty should be for 400 rwtq 300 rwhp ?

 

http://www.smokemup.com/auto_math/fuel_injector.php