Login






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

BMW 3Series (E90 E92) Forum
>
300 hp & 300 torque at 14001500RPM for 335


04032013, 04:32 PM  #1  
Colonel
47
Rep 2,291
Posts 
300 hp & 300 torque at 14001500RPM for 335
Is this technically possible that 335 makes 300HP and 300 torque at 14001500RPM?
Quote:
Dyno proves otherwise.. 

04032013, 04:44 PM  #2 
Major
15
Rep 1,054
Posts
Drives: 2011 E90 LCI 328i xdrive
Join Date: Mar 2011
Location: Winnipeg/Minneapolis

Dyno sheet says that it's for a 2007 which has the N54 engine. The link you provided is for a 2013 which has the N55 engine.
N55 engine builds peek torque earlier than N54. 
Appreciate
0

04032013, 04:47 PM  #3 
BMWCCA 149159
10
Rep 637
Posts 
You are comparing RWHP/RW torque to FHP/ Flywheel torque which are different. Actually BMW rates their engines as 0 +5%. The 335i is understated and consistently puts out more HP than what BMW advertised.
Also it very much depends on the dyno used as different dyno manufacturers use different methods to determine HP. The dyno used in this comparison was a Dynojet which typically provides different readings than say a Mustang will. Expect 15% mechanical loss and that should be a good number for RWHP/ RW torque... 
Appreciate
0

04032013, 04:58 PM  #5  
Colonel
47
Rep 2,291
Posts 
Quote:
I was thinking BMW was advertising 300HP at 1500 RPM. 

Appreciate
0

04032013, 05:18 PM  #7  
Captain
8
Rep 609
Posts 
Quote:
HP = Torque x RPM ÷ 5252 This is why on every dyno sheet and engine spec sheet HP is always equal to torque at 5252 RPM. Look at the img you provided, the torque and hp lines will always intersect at 5252. It is possible that the motor makes 300 peak hp, as well as 300 ft lbs of torque, but both can not occur at 14001500 rpm.
__________________
JB4 / BMS DCI / Alpina Flash / MTEC V3 / Blacklines M3 Front Bumper / HID Fogs / M3 Style Spoiler 

Appreciate
0

04032013, 05:46 PM  #8  
Private
1
Rep 54
Posts 
Quote:


Appreciate
0

04032013, 05:59 PM  #9 
Major
23
Rep 1,036
Posts 
You are reading the description wrong. BMW is not saying that it makes 300hp @ 1400 RPM. It says that it makes 300hp (with no specified RPM) and 300ftlbs @ 14001500.

Appreciate
0

04032013, 06:24 PM  #10 
Banned
19
Rep 1,587
Posts 

Appreciate
0

04032013, 06:27 PM  #11 
Captain
8
Rep 609
Posts 
For all engines, regardless of make or model. 5252 is a constant in the HP formula. HP always = torque X RPM / 5252. So at 5252 HP will always = torque.
__________________
JB4 / BMS DCI / Alpina Flash / MTEC V3 / Blacklines M3 Front Bumper / HID Fogs / M3 Style Spoiler 
Appreciate
0

04032013, 08:15 PM  #12  
Captain
16
Rep 970
Posts 
Quote:
Does 335i make 300HP max and 300 lb*ft max? Yes. Your dyno charts actually show pretty much exactly that, accounting for drivetrain losses. Does peak torque come at 14001500 RPM? Your chart shows that it actually comes around 2100 RPM. I don't know what caused that, but the maxtorque RPM value does tend to float around, depending on the conditions. Or is your question about something else? You do understand that "14001500 RPM" value applies to max torque only, not to max HP, right? By definition, max HP is always achieved later (i.e. at higher RPM) than max torque. And if the torque curve is relatively flat, then max HP is always achieved much later than max torque. Last edited by AndreyT; 04032013 at 08:29 PM. 

Appreciate
0

04032013, 08:22 PM  #13 
Captain
16
Rep 970
Posts 
What exactly? The formula? Yes, it applies to any rotating shaft at all. This is a purely physical formula, from high school physics book. This is actually the definition of power produced by any rotating shaft anywhere. It is equally applicable to cars, bicycles, blenders and washing machines.
Moreover, power cannot be measured directly. Power is not a fundamental physical quantity. It is product of human conceptual thinking. It doesn't really "exist" in real world, it only exists in human minds. For this reason there's no device that can measure power directly. Every device that claims to "measure power" actually measures something else and then calculates power from these measurements. When it comes to dynos, all dynos measure torque and only torque. HP is always calculated from measured torque by using the above formula. For this reason, every engine HP/torque chart agrees with that formula precisely, since this is actually how the HP line is drawn in the first place. Last edited by AndreyT; 04032013 at 08:30 PM. 
Appreciate
0

04032013, 09:58 PM  #14  
Lieutenant
6
Rep 472
Posts 
Quote:
__________________
335i Space Grey Coupe/ppk/ssk/pe exhaust/perf susp


Appreciate
0

04032013, 10:12 PM  #15 
Private First Class
1
Rep 101
Posts 
The owners manual states the xdrive produces much more torque than rwd.
However, this is the only place I've seen seen a difference in torque measurements between rwd/awd. Confirm/deny? 
Appreciate
0

04032013, 10:23 PM  #16 
Captain
10
Rep 946
Posts 
You would need to use an engine dyno to see where the bottom end of the max power is.
With the chassis dyno, there is minimal load without the wheels turning. So at the beginning of the test, you get poor power representation at lower RPM's until the dyno loads up. It's why most dyno graphs start at 20003000RPM. 
Appreciate
0

04032013, 11:55 PM  #17 
Private
0
Rep 74
Posts 
common sense please
the dyno graphs are in the 3rd or 4th gear runs.
if you have ur car in 1st gear then you do get 300tq at 1400 rpm. Last edited by dk79; 04042013 at 12:18 PM. 
Appreciate
0

04042013, 12:05 AM  #18  
Lieutenant Colonel
21
Rep 1,679
Posts
Drives: 14' GMC Terrain SLT2
Join Date: May 2011
Location: Folsom, Ca

Quote:
__________________
SOLD:: PTF Pro eTune by Dzenno / COBB S1+ E50 Alpina B3 Flash / ETS FMIC / ER CP / CPE DCI 

Appreciate
0

04042013, 12:10 AM  #19  
just another bmw douche bag
41
Rep 3,403
Posts 
Quote:
peak hp always comes after peak torque, by definition of the formula as stated above. 

Appreciate
0

04042013, 08:23 AM  #20  
Captain
8
Rep 609
Posts 
Quote:
Warning . . . numbers ahead! In order to properly understand why, we need to define a few things. These are sort of butchered from what I remember of physics. Force is a push or pull motion upon an object by another object. It is expressed by Newtons law of F= ma. This means force = mass x acceleration. The amount of force exerted is equall to an objects mass x how fast it is accelerated. The standard measurement of force is the newton. One newton is equal to the amount of force required to accelerate one kg of mass to the speed of 1 meter per second squared. One kilonewton is 1000 newtons. Anyone that does any recreational climbing, or industrial lifting is familiar with these since they are stamped on all of the equipment. Work is the amount of force applied over a distance or, W=Fd. In order for work to be performed it is necessary for a distance to be traveled. If you push a stalled BMW ( I know . . . never happens) down the road, you exert force over a distance and have performed work. If you attempt to push that same car down the road with the parking brake on, you have exerted the same amount of force, but no work is performed. Torque is force applied around a rotational axis. Tightening a bolt, turning on a faucet, or the rotation of the crankshaft in a motor are all examples of torque. Torque is measured in units of force, times the distance from the center of the axis. Torque is measured in poundfeet, not to be confused with foot pounds, which is the US measurement for work. Remember work and force are not the same thing. Here is how we start getting to HP. If you apply 1 lbft of torque to an object and get it to complete 1 rotation, you have accomplished 6.28 ftlb of work. What???? Remember high school geometry? The circumference of a circle is equal to 2(pi)R. Or 2(pi)r x 1 lbft of torque = 2 x 3.1416 x 1foot lever x 1 lbft = 6.2832 ftlb of work Power. Power is the speed at which work is being performed. In the above example, if your girlfriend made that rotation in 1 hour, she has performed 6.283 ft lb of work. Since you are a badass though, you can do it in 15 minutes. You have still completed 6.283 ft lb of work, but you have exerted more power, since you did it in one quarter of the time. Here is where the US’ standard of measurement rears its ugly head. In the US, power is measured in HP. 1 HP is = 33,000 ftlb of work performed in 1 minute. Remember, we need a time factor to evaluate power. Why 33,000? Because that is what a strong horse could do in one minute in the 1800’s, of course! This was evaluated by James Watt BTW, for future Jeopardy questions. The same Watt that came up with the way we measure electricity . . . but that is another rant. So here come the equations. HP = Torque X 6.2 X RPM / 33,000 This can be reduced to HP = Torque X RPM / 5252 So finally, now we can look at the dyno above. If the N54 makes 300 ft lbs of torque at 1500 RPM, we can figure out how much HP it makes. These are not the actual N54 numbers, I made them up to illustrate the point. HP = 300 X 1500 / 5252 HP = 450,000 / 5252 HP = 85 @ 1500 RPM. As someone else said, HP is not real. It is defined by torque. Plug in any RPM and torque numbers from above and you will get your HP numbers. Rant Over.
__________________
JB4 / BMS DCI / Alpina Flash / MTEC V3 / Blacklines M3 Front Bumper / HID Fogs / M3 Style Spoiler 

Appreciate
0

04042013, 01:04 PM  #21  
Captain
16
Rep 970
Posts 
Quote:
The constant 5252 comes from specific measurement units which are used to represent power and torque: HP for power and lbft for torque. When power is expressed in HP and torque is expressed in lbft, then the adjustment constant is equal to 5252 and the graphs intersect at 5252 RPM. So, apparently what you really wanted to say is: your HP and your lbft graphs will always intersect at 5252 RPM point. Not just "torque", but specifically lbft graph of torque. For different choice of measurement units the intersection point will be different. If you draw the same graphs in Watts and Nm units, they will intersect at around 10 RPM, meaning that on the reallife actual graph they won't intersect at all. If you draw the same graphs in kWatts and lbft units, you'll get yet another RPM for intersection point, and so on. Additionally, all of the above only makes sense if the values along the Yaxis for power and torque are perfectly synchronized, as in the OP's graph. USstyle dyno charts usually use the same Yaxis value for both HP and lbft graphs, meaning that you can expect to see the intersection at 5252 RPM all the time. In some cases they prefer to use different scales along the Yaxis, meaning that the intersection point can end up virtually anywhere. Last edited by AndreyT; 04042013 at 01:55 PM. 

Appreciate
0

04042013, 03:32 PM  #22 
2014 435MSport/MPPK
42
Rep 2,407
Posts 
Bottom line is the 300 & 300 is a good call by BMW. What they need is a better copywriter to make sure that after "AND" they also include the RPM behind the number.
That being said generally 99% of the people reading threads on this site would know what was intended.
__________________
Kevin
2014 435MSport MPPK/MPE  2013 135is Cab 6MT/JB4  2009 VStar FFR Cobra MKIV Dyno Tuned 446WHP Cobra Coyote First Start. 
Appreciate
0

Bookmarks 
Thread Tools  Search this Thread 

