Just dyno'd my M3. Do s2k's have excessive
05-10-2001, 04:30 PM
#1
Registered User
Thread Starter
Join Date: Oct 2000
Location: Austin
Posts: 652
Likes: 0
Received 0 Likes
on
0 Posts
drivetrain loss?
I got 215.5 hp and 217 ft-lbs. The operator said that he dynoed an s2k and it came in just under 200 hp. Since the s2k and M3 (E36) are both rated at 240 hp, it seems that there must be some extra loss in the s2k.
Just wondering what y'all thought.
I miss my s2k, and will get one again one of these days. Hopefully a used one that's never been vtec'd. LOL.
I got 215.5 hp and 217 ft-lbs. The operator said that he dynoed an s2k and it came in just under 200 hp. Since the s2k and M3 (E36) are both rated at 240 hp, it seems that there must be some extra loss in the s2k.
Just wondering what y'all thought.
I miss my s2k, and will get one again one of these days. Hopefully a used one that's never been vtec'd. LOL.
05-10-2001, 04:41 PM
#3
Registered User
Join Date: Mar 2001
Location: Sugar Land
Posts: 2,052
Likes: 0
Received 0 Likes
on
0 Posts
I was thinking about this too... it's about 20% if we are supposed to have 240hp. that means it's on the same level as most automatics.
The miata guys where talkinga bout the the other day at their dyno... they said it doesn't make 240hp. So any one what the story is?
-Shing
The miata guys where talkinga bout the the other day at their dyno... they said it doesn't make 240hp. So any one what the story is?
-Shing
05-10-2001, 04:55 PM
#4
Registered User
Let me guess frayed, you have a 3.2 liter M3?
How did I know you ask? Because the 3.2 liters are underrated from BMW. Yeah sure, they claim the same hp, but early 3.0 liter M3's rarely made more than 205-208 hp. Its not new with automakers, particularly if they don't want to alienate previous model year buyers.
Makes total sense too, if you look at the acceleration numbers from the 3.2 liter M-roadster. Just as quick or quicker than the S2K with 300 lbs more weight, hmmm...
Also, take a look at the numbers for the Boxster S. Typically put down about 210-215. And they're rated 10 hp higher than the S2K. Pretty well sync'd I'd say.
The typical S2K will put down around 200 hp broken in. My did 203 at 2500 miles and the range seems to go from 195-205 on dynojets.
UL
p.s. - higher revving engines seem to show larger losses at peak hp than lower revving ones. Why? Drivetrain losses - the faster you have to spin everything, the more friction you've got.
p.p.s. - the true way to examine drivetrain loss is to look at torque losses. If you have the 3.2, you're rated at 236 lbs-ft, which gives you a loss of about 19 lbs-ft. The typical S2K puts out 133-135 lbs-ft and is rated at 153, or a loss of 18-20 lbs-ft. Pretty much the same.
[Edited by ultimate lurker on 05-10-2001 at 06:00 PM]
How did I know you ask? Because the 3.2 liters are underrated from BMW. Yeah sure, they claim the same hp, but early 3.0 liter M3's rarely made more than 205-208 hp. Its not new with automakers, particularly if they don't want to alienate previous model year buyers.
Makes total sense too, if you look at the acceleration numbers from the 3.2 liter M-roadster. Just as quick or quicker than the S2K with 300 lbs more weight, hmmm...
Also, take a look at the numbers for the Boxster S. Typically put down about 210-215. And they're rated 10 hp higher than the S2K. Pretty well sync'd I'd say.
The typical S2K will put down around 200 hp broken in. My did 203 at 2500 miles and the range seems to go from 195-205 on dynojets.
UL
p.s. - higher revving engines seem to show larger losses at peak hp than lower revving ones. Why? Drivetrain losses - the faster you have to spin everything, the more friction you've got.
p.p.s. - the true way to examine drivetrain loss is to look at torque losses. If you have the 3.2, you're rated at 236 lbs-ft, which gives you a loss of about 19 lbs-ft. The typical S2K puts out 133-135 lbs-ft and is rated at 153, or a loss of 18-20 lbs-ft. Pretty much the same.
[Edited by ultimate lurker on 05-10-2001 at 06:00 PM]
05-10-2001, 05:03 PM
#5
Registered User
Thread Starter
Join Date: Oct 2000
Location: Austin
Posts: 652
Likes: 0
Received 0 Likes
on
0 Posts
Originally posted by Austin_S2000
Where did you get it dynoed at?
Where did you get it dynoed at?
UL,
Yes, I have the 3.2L. Your comments make sense to me. Interesting that a manufacturer would actually underrate a car; you'd think they would want to advertise "250" since the M3's competition (S4) makes 250.
Why is torque differential more indicative of drivetrain loss, particularly since hp is a fn of torque (torque x rpm x constant).
BTW, it was a really fun $60. I suggest it to anyone who is wondering about their car.
05-10-2001, 06:43 PM
#6
Point of Interest:
Many people have a misconception of Horsepower. They picture a 5 horsepower motor as literally 5 "horses". As a child when I boasted horsepower numbers on my mini-bike my dad would ask "how big are the horses". Really used to bug me! Horsepower is actually just a unit of work. James Watt invented this unit of measure in the 17th century. Watt was interested in "power". Watt gave the standard rate of 550 ft-lb/sec as 1HP. As Watt was a mechanical engineer by trade, a "Watt" was the rate of doing work as 1 Watt = 1 Joule/Second.
Most people think of the Watt as a unit of electric power, however the watt is fundamentally a mechanical unit. It is also sometimes useful to know that 746 Watts = 1 HP.
Sorry for this digression but it was part of my thesis in college
.
Many people have a misconception of Horsepower. They picture a 5 horsepower motor as literally 5 "horses". As a child when I boasted horsepower numbers on my mini-bike my dad would ask "how big are the horses". Really used to bug me! Horsepower is actually just a unit of work. James Watt invented this unit of measure in the 17th century. Watt was interested in "power". Watt gave the standard rate of 550 ft-lb/sec as 1HP. As Watt was a mechanical engineer by trade, a "Watt" was the rate of doing work as 1 Watt = 1 Joule/Second.
Most people think of the Watt as a unit of electric power, however the watt is fundamentally a mechanical unit. It is also sometimes useful to know that 746 Watts = 1 HP.
Sorry for this digression but it was part of my thesis in college
.
Trending Topics
05-10-2001, 09:45 PM
#9
Registered User
great info UL.
and Frayed - I'm glad you are still lurking around the board, seems to be the only way you can get good information eh?
And another thing, how is the baby and when do we get to see pics? After all, that was the primary reason of selling the S2k, right?
and Frayed - I'm glad you are still lurking around the board, seems to be the only way you can get good information eh?
And another thing, how is the baby and when do we get to see pics? After all, that was the primary reason of selling the S2k, right?
