BMW M3 Forum (E90 E92)

BMW Garage BMW Meets Register Search Today's Posts Mark Forums Read


Go Back   M3Post - BMW M3 Forum > E90/E92 M3 Technical Topics > Engine, Transmission, Exhaust, Drivetrain, ECU Software Modifications
 
ESS Tuning
Post Reply
 
Thread Tools Search this Thread
      08-31-2011, 01:19 PM   #1
Z K
Colonel
Z K's Avatar
United_States
26
Rep
2,174
Posts

 
Drives: E90 M3, MK6 GLI
Join Date: Jul 2011
Location: San Francisco

iTrader: (3)

Good article on why you can't compare dyno #s

Just saw this. Informative article.

Quote:
The moral of the story is that trying to compare dyno numbers from different dynos, locations, and weather conditions for bragging rights is borderline idiotic. The best case for trying to compare chassis dyno numbers between different cars is if both cars were tested on the same dyno in similar weather conditions. Use the dyno as intended, as a tool to measure how vehicle setup changes alter power output. Don't bench race.
http://www.motoiq.com/magazine_artic...lieve-one.aspx
Appreciate 0
      08-31-2011, 01:24 PM   #2
J08M3
Major General
J08M3's Avatar
United_States
102
Rep
6,012
Posts

 
Drives: 2011 M3 COUPE
Join Date: May 2008
Location: NEW YORK

iTrader: (8)

not very informative, just says dynos can't be compared. but thanks for link
__________________
Appreciate 0
      08-31-2011, 01:27 PM   #3
Z K
Colonel
Z K's Avatar
United_States
26
Rep
2,174
Posts

 
Drives: E90 M3, MK6 GLI
Join Date: Jul 2011
Location: San Francisco

iTrader: (3)

Quote:
Originally Posted by J08M3 View Post
not very informative, just says dynos can't be compared. but thanks for link
It goes into the reasons why, variables and calculations. I doubt you'd read the whole article in this short time period.

Something as simple as dyno strap tension can change the dyno reading.
Appreciate 0
      08-31-2011, 01:31 PM   #4
J08M3
Major General
J08M3's Avatar
United_States
102
Rep
6,012
Posts

 
Drives: 2011 M3 COUPE
Join Date: May 2008
Location: NEW YORK

iTrader: (8)

Quote:
Originally Posted by Z K View Post
It goes into the reasons why, variables and calculations. I doubt you'd read the whole article in this short time period.

Something as simple as dyno strap tension can change the dyno reading.
I read it, it's only 4 short paragraphs and a couple of tables. Nothing very in depth, just the usual stuff we always talk about here. Sorry, all I got from it.
__________________
Appreciate 0
      08-31-2011, 01:34 PM   #5
Z K
Colonel
Z K's Avatar
United_States
26
Rep
2,174
Posts

 
Drives: E90 M3, MK6 GLI
Join Date: Jul 2011
Location: San Francisco

iTrader: (3)

Quote:
Originally Posted by J08M3 View Post
I read it, it's only 4 short paragraphs and a couple of tables. Nothing very in depth, just the usual stuff we always talk about here. Sorry, all I got from it.
Great, glad you got the info.
Appreciate 0
      08-31-2011, 06:18 PM   #6
rjd598
Brigadier General
rjd598's Avatar
United_States
55
Rep
4,644
Posts

 
Drives: 10' M3
Join Date: Jan 2009
Location: San Diego,CA

iTrader: (2)

Garage List
2010 BMW M3  [4.50]
1999 BMW M3  [0.00]
i think most people can come up with that conclusion. key is to keep an open mind to the various conditions of a dyno like the article said when comparing dyno runs
__________________
Appreciate 0
      08-31-2011, 06:45 PM   #7
schnell325
Bored at work....
schnell325's Avatar
Canada
43
Rep
3,875
Posts

 
Drives: '08 M3,'11 335xi
Join Date: Aug 2007
Location: BC

iTrader: (5)

The turbo Vespa on page 3 was cool!!
__________________
'08 M3: AA G2L3, Catless X-Pipe & Sig Series Rear. AP rods. TC Kline EDC Coil Overs. MRF Alum Sub Frame Bushings. TMS Delrin Diff'l Bushings. BFI Motor Mounts. Recaro PP. BMW Perf Steering Wheel. P3 Gauge. PS Overflow Kit. APEX ARC-8 18"x9.5"/10.5". Conti Slicks 275/35F 305/30R. Stoptech Pads/SS Lines. Cantrell Brake Ducts.
http://5252motorsports.blogspot.ca/2...3-sleeper.html
Appreciate 0
      08-31-2011, 06:46 PM   #8
OG_M3
First Lieutenant
United_States
3
Rep
315
Posts

 
Drives: 1985 AE86 & E92 SG M3
Join Date: Mar 2008
Location: Vegas

iTrader: (2)

Garage List
2011 BMW M3  [0.00]
2007 BMW Z4MC  [0.00]
1985 AE86  [0.00]
Quote:
Originally Posted by J08M3 View Post
I read it, it's only 4 short paragraphs and a couple of tables. Nothing very in depth, just the usual stuff we always talk about here. Sorry, all I got from it.
you do know there are 3 pages right? think i counted more than 4 short paragraphs
Appreciate 0
      08-31-2011, 07:21 PM   #9
J08M3
Major General
J08M3's Avatar
United_States
102
Rep
6,012
Posts

 
Drives: 2011 M3 COUPE
Join Date: May 2008
Location: NEW YORK

iTrader: (8)

Quote:
Originally Posted by OG_M3 View Post
you do know there are 3 pages right? think i counted more than 4 short paragraphs
Nope. Didn't see that guess that explains it.
__________________
Appreciate 0
      08-31-2011, 10:32 PM   #10
OG_M3
First Lieutenant
United_States
3
Rep
315
Posts

 
Drives: 1985 AE86 & E92 SG M3
Join Date: Mar 2008
Location: Vegas

iTrader: (2)

Garage List
2011 BMW M3  [0.00]
2007 BMW Z4MC  [0.00]
1985 AE86  [0.00]
Quote:
Originally Posted by J08M3 View Post
Nope. Didn't see that guess that explains it.
all good, i missed it at first as well
Appreciate 0
      09-02-2011, 04:40 PM   #11
shay2nak
I <3 E90 M3
shay2nak's Avatar
United_States
2
Rep
288
Posts

 
Drives: 325i/Lotus Exige S
Join Date: Feb 2011
Location: Calipornia

iTrader: (0)

+1 you can only compare dynos from the same shop on similar days. Same dynojets, different shops can give you different numbers and don't even try comparing dynojet to dynapack... dyno is basically tuning tool and to see what gains (+ or -) you've made with your mods. I'm sure you guys know this anyway.
Appreciate 0
      09-02-2011, 05:31 PM   #12
DLSJ5
Brigadier General
DLSJ5's Avatar
United_States
89
Rep
3,497
Posts

 
Drives: 08 E92 DCT M3
Join Date: Dec 2006
Location: CA

iTrader: (1)

Send a message via AIM to DLSJ5
I think it is a little silly to compare different types of dyno's, DJ vs. DP or DJ vs. DD's, etc. in terms of making an argument that brand A makes more power than B, etc. But I think it's perfectly fine to compare Dynojet results, in the sports car enthusiast world the DJ really is the standard. For the most part, when the same CF's are applied to two different dynojet results, they are pretty accurate and unlike other dyno's they are very difficult to manipulate the results.

Last edited by DLSJ5; 09-02-2011 at 05:36 PM.
Appreciate 0
      09-02-2011, 05:48 PM   #13
Z K
Colonel
Z K's Avatar
United_States
26
Rep
2,174
Posts

 
Drives: E90 M3, MK6 GLI
Join Date: Jul 2011
Location: San Francisco

iTrader: (3)

Quote:
Originally Posted by DLSJ5 View Post
I think it is a little silly to compare different types of dyno's, DJ vs. DP or DJ vs. DD's, etc. in terms of making an argument that brand A makes more power than B, etc. But I think it's perfectly fine to compare Dynojet results, in the sports car enthusiast world the DJ really is the standard. For the most part, when the same CF's are applied to two different dynojet results, they are pretty accurate and unlike other dyno's they are very difficult to manipulate the results.
I wouldn't think the Dynojet is the "standard". They are just widely available and have been around longer so lots of places have it. Dynojets are not load bearing so the numbers you see are basically if there was no road resistance at all with the car essentially spinning the hubs freely. Dynojet numbers will consistently be higher than other dynos because of this. So if you want dyno #s for bragging rights, the dynojet is the one to use.

Mustang dynos are load bearing. Among tuners, it is one of the most widely used ones for accurate tuning as it will give closer real world road conditions. All the dyno operators in my area are running Mustang or Dyno Dynamics dynos.

Here's some more info.
http://g35driver.com/forums/266175-post1.html
Also Googling "Dynojet vs Mustang" will give a lot more info.
Appreciate 0
      09-02-2011, 05:55 PM   #14
E90///M3`
Major General
Philippines
62
Rep
5,278
Posts

 
Drives: 2008 E90M3
Join Date: Jan 2009
Location: Daly City -4- Work///Camarillo is Home

iTrader: (3)

Garage List
2008 BMW E90 M3  [3.80]
i think this has been brought up and too many times already.

__________________
- Jason P
:Have: 08 E90M3, Varis VRS Front Lip, LS3, ESS Supercharger, Arqray Exhaust, Neez Wheels
:Want: VRS Carbon GT Wing & Cooling Bonnet, LCI Taillights
:Videos: EnvyRidesTV, GPR 1, GPR 2, GPR 3, ///MFEST
Appreciate 0
      09-02-2011, 07:39 PM   #15
DLSJ5
Brigadier General
DLSJ5's Avatar
United_States
89
Rep
3,497
Posts

 
Drives: 08 E92 DCT M3
Join Date: Dec 2006
Location: CA

iTrader: (1)

Send a message via AIM to DLSJ5
Quote:
Originally Posted by Z K View Post
I wouldn't think the Dynojet is the "standard". They are just widely available and have been around longer so lots of places have it. Dynojets are not load bearing so the numbers you see are basically if there was no road resistance at all with the car essentially spinning the hubs freely. Dynojet numbers will consistently be higher than other dynos because of this. So if you want dyno #s for bragging rights, the dynojet is the one to use.
That is why, at least in the BMW platform, that is it considered the "standard." I didn't say it should be, didn't say it's the most accurate, nor did I say it was the best dyno for tuning, but it certainly is the most widely used / compared dyno in this platform and probably the world, especially in FWD or RWD platforms. In the GTR or AWD platforms the Mustang is probably the standard.

As far as a DJ reading high for bragging rights, most stock E9x M3's read 330-340whp SAE on a DJ, that's quite a bit of drivetrain loss to hit the rated 414BHP, but you're right, I think it's universally accepted and well known that DJ's for the most part do read higher than Mustang's.
__________________
08 E92 M3 DCT - Bolt Ons - 60-130MPH 10.71s - 11.88 @ 118MPH - 377WHP
ESS VT2-625 SC 60-130MPH 6.80s - 11.30 @ 129.3 MPH 586WHP / 379WTQ
ESS VT3-750 - 60-130MPH 6.44s - 10.81 @ 135.13 MPH 690Whp/463Wtq
Appreciate 0
      09-02-2011, 07:40 PM   #16
DLSJ5
Brigadier General
DLSJ5's Avatar
United_States
89
Rep
3,497
Posts

 
Drives: 08 E92 DCT M3
Join Date: Dec 2006
Location: CA

iTrader: (1)

Send a message via AIM to DLSJ5
Quote:
Originally Posted by E90///M3` View Post
i think this has been brought up and too many times already.

Agreed.
__________________
08 E92 M3 DCT - Bolt Ons - 60-130MPH 10.71s - 11.88 @ 118MPH - 377WHP
ESS VT2-625 SC 60-130MPH 6.80s - 11.30 @ 129.3 MPH 586WHP / 379WTQ
ESS VT3-750 - 60-130MPH 6.44s - 10.81 @ 135.13 MPH 690Whp/463Wtq
Appreciate 0
      09-03-2011, 03:16 PM   #17
swamp2
Lieutenant General
swamp2's Avatar
United_States
214
Rep
10,201
Posts

 
Drives: E92 M3
Join Date: Sep 2006
Location: San Diego, CA USA

iTrader: (1)

And this is all highly relevant for the debate on the topic of the effectiveness of M-DCT vs. MT in tuned M3s.

Apples to oranges baby, apples to oranges, just like I said (and said previously)...
Appreciate 0
      09-04-2011, 02:52 AM   #18
shay2nak
I <3 E90 M3
shay2nak's Avatar
United_States
2
Rep
288
Posts

 
Drives: 325i/Lotus Exige S
Join Date: Feb 2011
Location: Calipornia

iTrader: (0)

Quote:
Originally Posted by DLSJ5 View Post
I think it is a little silly to compare different types of dyno's, DJ vs. DP or DJ vs. DD's, etc. in terms of making an argument that brand A makes more power than B, etc. But I think it's perfectly fine to compare Dynojet results, in the sports car enthusiast world the DJ really is the standard. For the most part, when the same CF's are applied to two different dynojet results, they are pretty accurate and unlike other dyno's they are very difficult to manipulate the results.
you can't even compare dynojet results from different shops. Not unless you have a dyno baseline from a car who's power is widely known (using only NA). For example, an Elise will dyno 167/120 on a DJ. This is what it's supposed to show. There have been others who've pulled as low as 153/111 on DJs. Even the DJ that I use - I have a strong suspicion - is one of these lower reading DJs. I can't use my own car as a bearing because of it being supercharged and haven't been able to find an elise to do it (well i did and the guy's car was not stock at all when he said it was).
Appreciate 0
      09-04-2011, 11:29 AM   #19
DLSJ5
Brigadier General
DLSJ5's Avatar
United_States
89
Rep
3,497
Posts

 
Drives: 08 E92 DCT M3
Join Date: Dec 2006
Location: CA

iTrader: (1)

Send a message via AIM to DLSJ5
Quote:
Originally Posted by shay2nak View Post
you can't even compare dynojet results from different shops. Not unless you have a dyno baseline from a car who's power is widely known (using only NA). For example, an Elise will dyno 167/120 on a DJ. This is what it's supposed to show. There have been others who've pulled as low as 153/111 on DJs. Even the DJ that I use - I have a strong suspicion - is one of these lower reading DJs. I can't use my own car as a bearing because of it being supercharged and haven't been able to find an elise to do it (well i did and the guy's car was not stock at all when he said it was).
Sure there can be anomalies, people that don't disclose mods, and of course the #'s are probably not going to be the same from DJ to DJ, but obviously most can see if there is something out of the ordinary when the #'s are vastly different.
__________________
08 E92 M3 DCT - Bolt Ons - 60-130MPH 10.71s - 11.88 @ 118MPH - 377WHP
ESS VT2-625 SC 60-130MPH 6.80s - 11.30 @ 129.3 MPH 586WHP / 379WTQ
ESS VT3-750 - 60-130MPH 6.44s - 10.81 @ 135.13 MPH 690Whp/463Wtq
Appreciate 0
      09-04-2011, 04:24 PM   #20
IMG
M.POWER
IMG's Avatar
104
Rep
7,066
Posts

 
Drives: E36 M3 Track car,Ess E90 M3 DD
Join Date: Feb 2008
Location: Location

iTrader: (6)

The article makes some very valid and fairly obvious points:
1. Don't compare different brand dynos
2. SAE correction doesn't work when you run a dyno outside of the
formula's specified parameters.
3. It's possible to manipulate the results through strap tension
and altering the weather station data.

Luckily, nobody really does these things (other one or two known
dyno cheaters) and it's rare that a dyno is operated outside of
the SAE correction specification.

Here's a few things I also noticed about the article. The author
seems to have quite a bit of faith, in fact he even says SAE
correction is very accurate when used within it's operating
parameters. Another way to look at that is to say, that when you
don't compare apples to oranges (Mustang vs. Dynojet but keept
Dynojet vs. Dynojet) and when the dyno is run with SAE correction
within specifications, then the results really can be compared --
and compared pretty reliably (assuming strap tension is the
same).

Many people make a big deal about different weather conditions and
use that to say results can't be compared. But they don't realize
that SAE correction was designed specifically to correct for
weather and specificially to allow results to be compared. That's
literally why the SAE correction formula was invented. And
according to the author himself, when a dyno is run within the SAE
formula's specifications, then the correction is very accurate and
very reliable.

Quote:
Originally Posted by swamp2
And this is all highly relevant for the debate on
the topic of the effectiveness of M-DCT vs. MT in tuned
M3s.
Swamp, I think you're trying to grasp at straws here to explain
why a supercharged DCT with less power can still trap higher than
a supercharged 6MT with more power. It sounds like you're
assuming that the dyno's were run incorrectly or that the weather
conditions played a major role in the outcome (visa vis dyno
operated outside of SAE specifications). As we've said a few
times already, some of the cars in those videos were dyno'd on the
same dyno with same exact weather conditions. Two cars were
dyno'd 24 hours apart on the same dyno with same exact weather
conditions, and two other cars were dyno'd on the same exact day,
on the same exact dyno only hours apart and also on the same exact
weather conditions. I've given you the links to the Dyno Database
files so you could download them yourself and verify the weather
conditions. It sounds like you've never done this because you're
still looking for anything to explain how these results fall
outside of your own understanding.

Quote:
Originally Posted by swamp2
Please start another thread. A good topic might be
"the importance of DCT for drag racing" or something along those
lines. I promise I will have a closer look at your results and
reply with my own simulations.

One point does immediately stand out though. Your losses are
almost for sure incorrect. Incorrect based on real world
validations as well as text book values. Run your losses with a
standard power car and see how far off you are from the best
reported magazine times! If your losses are off (too high) but
results are right then you are right for the wrong reason and thus
a likely conclusion would that true power is actually a bit higher
than your input power.
I'll let you start the new thread. I already know how this plays
out in real life and how CarTest has already validated these
results itself. The only losses I find in CarTest are the
transmission losses. We've used the actual dyno charts and used
"At the wheels" for power rating. When you do this, CarTest
ignores the losses input into the program. Again, please verify
this yourself to make sure we are talking about the same thing.
It still looks like you're trying to find something to explain
these results because you don't understand it. Input the exact
values I posted for CarTest and then play with the losses. It
doesn't change the simulation results, and these simulation
results seem to perfectly match the real world results we've seen.
Don't forget, we've run some of these cars in real life --
including the ones that went to the same exact dyno on the same
exact day. The real life results were no different than the vBox
Racer and CarTest simulation results. So I'll leave it to you to
start a new thread if/when you find something wrong with the
simulations we've run, or if/when you find something wrong with
the dyno files I asked you to look at.
__________________
NO FEAR.NO LIMITS.NO EQUAL

Ess VT3 LC built motor,Volk TE37SL,Euro taillights,Dinan Xpipe,Custom Headers,Akra axle back CF tips,ModeCarbon FR lip,BMW CF wing
LOW BOOST 60-130 6.7 sec
Appreciate 0
      09-05-2011, 12:25 AM   #21
shay2nak
I <3 E90 M3
shay2nak's Avatar
United_States
2
Rep
288
Posts

 
Drives: 325i/Lotus Exige S
Join Date: Feb 2011
Location: Calipornia

iTrader: (0)

To make comparisons even more accurate, regardless of the weather, one could note the IAT during each pull. I typically have my OBD reader hooked up and I'll note it down.

Last edited by shay2nak; 09-05-2011 at 12:42 AM.
Appreciate 0
Post Reply

Bookmarks

Thread Tools Search this Thread
Search this Thread:

Advanced Search

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Forum Jump


All times are GMT -5. The time now is 06:39 AM.




m3post
Powered by vBulletin® Version 3.7.0
Copyright ©2000 - 2014, Jelsoft Enterprises Ltd.
1Addicts.com, BIMMERPOST.com, E90Post.com, F30Post.com, M3Post.com, ZPost.com, 5Post.com, 6Post.com, 7Post.com, XBimmers.com logo and trademark are properties of BIMMERPOST