** My car was dynoed at an altitude 5200 feet above sea level! My car ran 15.05 @ 94 at 5800 feet above sea level. NHRA calculates that to 13.9. Altitude also affects HP! **

car is baisically stock, mods are in sig
my readings were:

219.8 HP
377.0 TQ
(my teacher took it off the screen before i could see RPM)

- does this seem right to you guys? why is there such a big gap between HP & TQ?
-why do i have so much torque? does altitude even affect torque??

 

HP looks about right for that altitude, maybe just a toutch low. Torque is way high. Are you sure it's not 277?

 

yeah, i couldnt beleive my eyes.

i kept looking back at it making sure it was a 3 .... sure enough 377..

 

SSnakeEater--I'm not to bright on this so enlightening me, how does allititude affect hp and et times??

 

The more air you can get into your engine the more power it will produce. The higher you go in altitude the air gets thinner and thinner and harder to force more air molecules into the engine. its harder to breathe up here also. some olympic athletes train up here so when they get to lower altitudes its easier on their lungs.

 

yup



Something IS way off with your TQ numbers, thats way higher then anything I have seen for your mods.


what kind of dyno was it on?

 

its called Mustang Dynomometer, thats the brand

 

That is significant to a point. In general mustang dynos are varying percentages less than dynojets. anywhere from ~5%-15% it seems.

 

Yea, corrected for a Dynojet, you should be between
231 and 253 HP

That would be about right for that high of a altitude, or at least it seems justifiable to me . You mentioned a teacher ... Any chance he would let you strap it down again and make a few more pulls ? Something is very wrong for the TQ, it should be at least 60LBS less, probably even more.

Your car is a M6 rite ? What gear did you pull in ? I believe M6's usually pull in 4th gear. Check with someone else to make sure though cause I've never had mine dyno'd...

 

Yeah M6 cars pull in 4th gear.

 

Were the dyno numbers "SAE corrected"?

 

I thought dynos were always SAE corrected. Maybe not though....

 

Mustange Dyno's are NOT SAE corrected.

and are gennerally pull lower numbers.

They were not made for horsepower ratings, they were made for speedo calibrations.

 

No they are not. They can only measure the vehicles (approximate) rear wheel HP, under the prevailing atmospheric conditions. It is necessary to calcualte the correction to some sort of standard. The Dynojet software allows you to leave the data in raw form, or convert it to "SAE", "DIN, "JIS" or several other standards. Your dyno sheets, whether a graph or a table, should include the corrections method.

For some factual info on chassis dynos, check the article in the current (May 2004) issue of Hot Rod magazine.... compares 4 different manufacturers (Dynojet, Mustang, Dynapack and Suprflow), and does a comparison of the same car measured on each system. This article has got some good reviews on the "Advanced Tech" board.

 

Just ask the dyno technician what correction factor
is used. On the SuperFlow dyno I use the correction
is STP which is typically 4% higher than SAE due to
the data being normalized to a different temperature
and pressure.

Background Info:

SAE (Society of Automotive Engineers), USA. Power
is corrected to reference conditions of 29.23 InHg (99 kPa)
of dry air and 77 F (25 C). This SAE standard requires a
correction for friction torque. Friction torque can be determined
by measurements on special motoring dynamometers (which
is only practical in research environments) or can be estimated.
When estimates must be used, the SAE standard uses a default
Mechanical Efficiency (ME) value of 85%. This is approximately
correct at peak torque but not at other engine operating speeds.
Some dynamometer systems use the SAE correction factor for
atmospheric conditions but do not take mechanical efficiency
into consideration at all (i.e. they assume a ME of 100%).

STD or STP Another power correction standard determined
by the SAE. This standard has been stable for a long time and is
widely used in the performance industry. Power is corrected to
reference conditions of 29.92 InHg (103.3 kPa) of dry air and 60 F
(15.5 C). Because the reference conditions include higher pressure
and cooler air than the SAE standard, these corrected power
numbers will always be about 4 % higher than the SAE power
numbers. Friction torque is handled in the same way as in the
SAE standard.