[scheherazade]

Some people are dyno'ing over 300 stock whp. I hope they understand that it's wishful thinking.


Here's a more down to earth dyno pull.
My car runs perfectly fine, and pulls hard.


With 300 crank hp ...
rwhp should be around : 300 * 0.85 = 250 rwhp
awhp should be around : 300 * 0.80 = 240 awhp.


This post on M5 board describes the differences in dynos :
http://www.m5board.com/vbulletin/e39...g-dynojet.html


In any case, here are the results, taken on a 'dyno dynamics' dynamometer. No inflated results.

HP/TQ :
http://www.flickr.com/photos/30114567@N06/3956875101/

AFR :
http://www.flickr.com/photos/30114567@N06/3956875213/


Does it matter? Not really.
It just let you know why most glory runs are on a dynojet.


-scheherazade

[Jonny550]

thats def not right almost everyone that does a stock dyno makes anywhere from 255-280 depending on weather and dyno prep.i personally dynod a 271.4 whp stock on a dynojet on a 95% humidity and 95 degree florida day.

[scheherazade]

Originally Posted by Jon335iFL

thats def not right almost everyone that does a stock dyno makes anywhere from 255-280 depending on weather and dyno prep.i personally dynod a 271.4 whp stock on a dynojet on a 95% humidity and 95 degree florida day.

Correct. That's about what a dynojet would read.

This run was not on a 'dynojet', it was on a 'dyno dynamics'.

-scheherazade

[Hollywood Hogan]

wow thats really low...so your saying other dyno's are giving 40 more rwhp?

[scheherazade]

Originally Posted by Hollywood Hogan

wow thats really low...so your saying other dyno's are giving 40 more rwhp?

Generally :

'dyno dynamics' is conservative, reading low.

'mustang' falls on both sides from place to place.

'dynojet' is optimistic, reading a little high.

'dyna pack' is even more optimistic.


Specifc numbers depend on calibration. But yes, depending on the dyno, you can have 'virtual' power gains.


Read this link on M5 board :
http://www.m5board.com/vbulletin/e39...g-dynojet.html

You can ball park things by just taking crank hp and multiplying by 0.88 -> 0.85 for rwhp.
And for awhp, you can do 0.85 -> 0.82

I like to use round numbers, so I estimate with 0.85 rw and 0.80 aw.

-scheherazade




note :

To know true whp, you would have to :

1) know the exact weight of your car + you + liquids + etc .. basically as it stands
2) accelerate from a roll, up to redline.
3) record your positions at regular time intervals.
4) differentiate the positions to get velocity, and differentiate again for acceleration
5) use f=ma and (f*d)/t to convert acceleration to force and work
6) convert force and work to torque and horsepower

You can't mis-calibrate reality :P

-scheherazade

[canrhea]

Originally Posted by scheherazade

Some people are dyno'ing over 300 stock whp. I hope they understand that it's wishful thinking.


Here's a more down to earth dyno pull.
My car runs perfectly fine, and pulls hard.


With 300 crank hp ...
rwhp should be around : 300 * 0.85 = 250 rwhp
awhp should be around : 300 * 0.80 = 240 awhp.


This post on M5 board describes the differences in dynos :
http://www.m5board.com/vbulletin/e39...g-dynojet.html


In any case, here are the results, taken on a 'dyno dynamics' dynamometer. No inflated results.

HP/TQ :
http://www.flickr.com/photos/30114567@N06/3956875101/

AFR :
http://www.flickr.com/photos/30114567@N06/3956875213/


Does it matter? Not really.
It just let you know why most glory runs are on a dynojet.


-scheherazade

so your saying the n54 should be at 250 and anything over is just manipulated by the dyno operator??
lol, did you just discover this new found knowledge and now think you know it all. Bet you coudnt wait to post this and show how smart you are.
This thread is useless and wrong.. just cause bmw said its 300 hp it doesnt mean that anything over 250whp is not true.

[scheherazade]

Originally Posted by canrhea

so your saying the n54 should be at 250 and anything over is just manipulated by the dyno operator??
lol, did you just discover this new found knowledge and now think you know it all. Bet you coudnt wait to post this and show how smart you are.
This thread is useless and wrong.. just cause bmw said its 300 hp it doesnt mean that anything over 250whp is not true.

I have posts talking about this from ages ago. Feel free to search.
This is nothing new. Common knowledge in most car forums.
Just felt like posting a run that's on a conservative dyno, rather than an optimistic one.
I mention that the dyno reads low.
Take from it what you will.

-scheherazade

[wsybert]

I think he is saying that dynos report HP differently. I always thought that the 270+ dyno numbers I see are high... but if BMW reports the crank number low, then it would make sense. Dyno's are best at showing differences, not actual HP. Who cares if the car has 250 or 280 HP stock?
Not sure why his post is useless... it not magic, it's just math.

[scheherazade]

Originally Posted by wsybert

I think he is saying that dynos report HP differently. I always thought that the 270+ dyno numbers I see are high... but if BMW reports the crank number low, then it would make sense. Dyno's are best at showing differences, not actual HP. Who cares if the car has 250 or 280 HP stock?
Not sure why his post is useless... it not magic, it's just math.

We shouldn't be hung up on numbers.
It takes away from the enjoyment when you feel like you're coming up short.
Person A can dyno 350, and person B can dyno 380 (same mods)
But person A's car might actually be a little faster.
Person A shouldn't feel sad that he scored a lowly 350 with the same mods.
If it feels fast, it's fast.
Have fun

-scheherazade

[Ilma]

Originally Posted by scheherazade

Generally :


You can't mis-calibrate reality :P

-scheherazade

Lol.....mentally illl people do this everyday

[TheAcAvenger]

I dynoed 277whp and 289wtq with just a catback on a dynojet at sea level.

I'd say dynojets are slightly optimistic, but I still refuse to believe that the n54 puts 300 to the crank. My legal run-ins with G35s, G37s, and 350zs and even the E46 M3 would lead me to believe that the number has to be somewhere around 320

[Universal_Magnetic]

doesnt the 335i put out more than 300 crank anyways...probably why people are seeing 260-275whp stock. it doesnt really matter anyways, it all depends on your location, temp, humidity, etc. what matters is the change of the number relating to mods.

[OM3G@]

Originally Posted by Universal_Magnetic

doesnt the 335i put out more than 300 crank anyways...probably why people are seeing 260-275whp stock. it doesnt really matter anyways, it all depends on your location, temp, humidity, etc. what matters is the change of the number relating to mods.

+1
BMW is notorious for underrating their engines.

[scheherazade]

Originally Posted by Universal_Magnetic

doesnt the 335i put out more than 300 crank anyways...probably why people are seeing 260-275whp stock. it doesnt really matter anyways, it all depends on your location, temp, humidity, etc. what matters is the change of the number relating to mods.

If 300 crank with 15% drive train loss is 250 at the wheels.
To read 270 at the wheels, the dyno only needs to be 20hp optimistic.

Reading 20 hp high for a dynojet is nothing unusual, as they normally read a little high.

Reality can be anywhere in between.
Could be anywhere from 'all virtual gains' to 'all underrated power'
Depends on calibration.


Drive train loss is only an estimate.
Numbers anywhere from 10% (optimistic) to 20% (pessimistic) get thrown around.


270 is not a figure anyone should worry about.
However some people have hit near 300 stock, which is a stretch.



-scheherazade

[cu_north]

I think the problem with dynos in general is that they seem to vary more than the cars themselves.

Really if everyone can just stick to a dyno in their area, do a baseline and then use the same dyno when mods are applied, measure the difference. That's the most important, IMO.

[mylydiamy]

I have heard that the same car dynoed with the same type of dyno BUT at 2 different locations (same temperature/humidity/air pressure/altitute..) got different results of 15hp.

Is this possible or just a mith???

[Terrance28]

But haven't we already establish that the 335i is underrated already?

[Sniz]

Originally Posted by mylydiamy

I have heard that the same car dynoed with the same type of dyno BUT at 2 different locations (same temperature/humidity/air pressure/altitute..) got different results of 15hp.

Is this possible or just a mith???

of course thats possible

[Ramos]

That's why dyno numbers mean nothing... All they should be used for is measuring delta from mods... So base run, then modded run and take the difference...
Any other use of dyno numbers is just a cock measuring contest

[mylydiamy]

Originally Posted by Sniz

of course thats possible

If it is possible, then using the same dyno as measuring stick to see the diff between before and after mods is NOT 100% reliable. For example, if you have a mod which gave you +10hp can be shown as zero or 20hp gain by the same dyno. Aggree???

[Sniz]

Originally Posted by mylydiamy

If it is possible, then using the same dyno as measuring stick to see the diff between before and after mods is NOT 100% reliable. For example, if you have a mod which gave you +10hp can be shown as zero or 20hp gain by the same dyno. Aggree???

no thats wrong. You said before same dyno type but 2 different locations. Now your saying same dyno. Big differnece.

assuming you use the SAME dyno at the SAME location and they have not changed calibrations then yes you can use it as a measuring stick. Thats the only way it will mean anything.

Of course a dyno is very useful in tuning but thats a different story.

[TreDirtyFive]

From what I know, the car IS NOT underrated. I had a lengthy conversation with a head BMW tech/trainer/guide at BMW's own South Carolina Track grounds for media and owner training/testing. There were so many people with their modded Procedes (2 of which overheated and limped on the track), and what not, there to do personal drivers training, scoffing to the tech how they know BMW is underrating the cars etc. etc. The tech laughed back and said you can let the car cool down for 2 hours and dyno a realistic 320+ flywheel but it is not realistic on the road and on the track. Their aim is to hold a consistent 300hp even after its hot and beaten on. They wanted to be able to make 300hp even after 10 dyno runs in a row with almost no cool down time in between. We all know that's tough for turbocharged engines to sustain but it makes total sense.

Oh, and the instructor dusted and destroyed the modded Procede cars in his totally stock non-sport 335i. Of course knowing the track and knowing how to drive is the key here...not power. Anyhow, take it for what it's worth. Some might refuse to believe it's not underrated and need to validate the money they spent on their cars and that it is faster than god himself. You know you're out there. But, enjoy it...the powerplant has won numerous awards for a reason. Cheers!