Great Article on measuring Horsepower

GTO · 29th April 2004, 20:44

Hey,

Just found this great Car&Driver Article on measuring your cars horsepower.

Sure didnt know Chassis dynamometers can lie so much, especially in the newer breed of cars. Dont be surprised if your Enzo turns the gauge at "only" 450 bhp.

GTO

Rehaan · 30th April 2004, 08:53

Hey GTO,

SUPERB article. We had had a dyno discussion on TBHP where i stated that HP dyno'd at the rear wheel is usually considered to be .80 - .85 of the HP at the crank.

Also i just wanted to mention that the result difference with a 10mph fan and 75mph fan was not only coz of the temperature issues that the article seemed to concentrate on but also goes back to the "old fashioned" issue of how much air is the engine devouring!

cya
Rehaan

GTO · 30th April 2004, 11:56

Hey great point Rehaan. But this article just got out the fact that chassis dynamometers can be painfully unreliable. I mean, its cool if you want to see what effects your mods have had in %, what you could probably do is measure the BHP before mods and then meaure it again IN THE SAME CONDITIONS. But even then, I would be really disappointed to have my Vtec read out only 90bhp or something in the measurements. After all, how many workshops would have the space and money to invest in a 70mph fan?

If you have a chance, why not go down to a local garage and watch them dynoing other cars? I would love to know more about the experience, but hardly had the time to sit through a full session when I was in Boston. And yes, dont forget your cam

GTO

Rehaan · 30th April 2004, 12:22

Hey GTO,

True that replicating the exact conditions is close to impossible, but then do keep in mind that even if your are dynoing at the crank you still run into the exact same problems!
Personally i prefer the chasis dyno...(even though it takes 15+% off the "specified" power of your car, just because it gives the true horsepower that meets the road!

When i was visiting my uncle he was telling me about how he was part of a S2000 forum (s2ki.com) and they were planning a meet to go and dyno their cars together at a nearby shop!!
Someday we at team-bhp will be in the same situation......

But will try and visit a shop with my cam as a filler

cya
Rehaan

Domnic · 1st May 2004, 00:17

Hi guys,
* Just thought id let you guys know. We were racing a Porsche with the white Supra... just testing around. And a huge gang of imported cars. J Anand also had come. He told me he has a dyno now and asked us to visit him for tuning purposes. Pretty cool!!. Hes a cool dude.

Cheers
Dom

29th April 2004, 20:44	#1
GTO Team-BHP Support Join Date: Feb 2004 Location: Bombay Posts: 71,864 Thanked: 321,680 Times View My Garage	Hey, Just found this great Car&Driver Article on measuring your cars horsepower. Sure didnt know Chassis dynamometers can lie so much, especially in the newer breed of cars. Dont be surprised if your Enzo turns the gauge at "only" 450 bhp. GTO
	() Thanks

30th April 2004, 08:53	#2
Rehaan Team-BHP Support Join Date: Feb 2004 Location: Bombay Posts: 24,203 Thanked: 36,084 Times	Hey GTO, SUPERB article. We had had a dyno discussion on TBHP where i stated that HP dyno'd at the rear wheel is usually considered to be .80 - .85 of the HP at the crank. Also i just wanted to mention that the result difference with a 10mph fan and 75mph fan was not only coz of the temperature issues that the article seemed to concentrate on but also goes back to the "old fashioned" issue of how much air is the engine devouring! cya Rehaan
	() Thanks

30th April 2004, 11:56	#3
GTO Team-BHP Support Join Date: Feb 2004 Location: Bombay Posts: 71,864 Thanked: 321,680 Times View My Garage	Hey great point Rehaan. But this article just got out the fact that chassis dynamometers can be painfully unreliable. I mean, its cool if you want to see what effects your mods have had in %, what you could probably do is measure the BHP before mods and then meaure it again IN THE SAME CONDITIONS. But even then, I would be really disappointed to have my Vtec read out only 90bhp or something in the measurements. After all, how many workshops would have the space and money to invest in a 70mph fan? If you have a chance, why not go down to a local garage and watch them dynoing other cars? I would love to know more about the experience, but hardly had the time to sit through a full session when I was in Boston. And yes, dont forget your cam GTO
	() Thanks

30th April 2004, 12:22	#4
Rehaan Team-BHP Support Join Date: Feb 2004 Location: Bombay Posts: 24,203 Thanked: 36,084 Times	Hey GTO, True that replicating the exact conditions is close to impossible, but then do keep in mind that even if your are dynoing at the crank you still run into the exact same problems! Personally i prefer the chasis dyno...(even though it takes 15+% off the "specified" power of your car, just because it gives the true horsepower that meets the road! When i was visiting my uncle he was telling me about how he was part of a S2000 forum (s2ki.com) and they were planning a meet to go and dyno their cars together at a nearby shop!! Someday we at team-bhp will be in the same situation...... But will try and visit a shop with my cam as a filler cya Rehaan
	() Thanks

1st May 2004, 00:17	#5
Domnic Senior - BHPian Join Date: Mar 2004 Location: bangalore Posts: 427 Thanked: 6 Times	Hi guys, * Just thought id let you guys know. We were racing a Porsche with the white Supra... just testing around. And a huge gang of imported cars. J Anand also had come. He told me he has a dyno now and asked us to visit him for tuning purposes. Pretty cool!!. Hes a cool dude. Cheers Dom
	() Thanks