BimmerFest BMW Forum banner

n55 vs n55HP - How do we get that extra power and torque?

18K views 65 replies 18 participants last post by  PeterC4 
#1 ·
I see that the N55HP has 13 more hp and 30 lb/ft torque vs the standard N55 in our F10. The N55hp comes in the 2012 and newer: F12 (6-series), F21 (1-series) & F01 (7-series).

Anyone know exactly how this power is achieved and if we can buy some OEM parts to obtain the extra power and torque of the N55HP?
 
#2 · (Edited)
15hp is not really a noticeable difference, not sure why you want to do that.
If you want more power, the best bet is a tune.
I highly recommend the N55 Burger tune I have in my car. It's +50hp and +80 torque for $500 bucks. The power is night and day.
 
#6 ·
I guess my thread turned into a BMS tune infomercial :rolleyes:. The point of this thread is not to get into a debate about TRUE power gains with piggyback tunes. I simply want to know how the power gains are had with the N55HP.


From my past experience, these slight power gains were often had from tweaked intake and exhaust manifolds. Of course with FI (forced induction) vehicles, all it takes is a little programming and or an increase in boost.
 
#8 ·
I guess my thread turned into a BMS tune infomercial :rolleyes:. The point of this thread is not to get into a debate about TRUE power gains with piggyback tunes. I simply want to know how the power gains are had with the N55HP.

From my past experience, these slight power gains were often had from tweaked intake and exhaust manifolds. Of course with FI (forced induction) vehicles, all it takes is a little programming and or an increase in boost.
I would think it's the latter since it is very economical to do from the factory. But it would be interesting to get the details. Maybe it's similar to the 335 BMW performance upgrades from the dealer.
 
#7 ·
I'm curious about this as well. I posted in the F12 Forum the question of what the N55HP has that's different from the N55 that gives it that little extra boost in power.

What I'm really curious about is how much REAL power it has over the N55, as the N55 is very underrated (at 280 RWHP putting it around 330-340 actual crank HP).
 
#9 ·
How are you calculating that... lol 330-340??? You add 10%-12% which puts you right at 310. Not arguing with the number just your calculation. :dunno:

I am hoping to dyno my car some time next week or two - time permitting. Then I will throw on the stage 1 (If I can ever get it back from my deadbeat friend bigdeep:rofl:) Then I will post some numbers.

BigD - I believe the answer to your question is going to be software. I tried searching for you, but everything just says "fine tuning" This to me indicates that perhaps it was nothing mechanical.
 
#16 ·
From what I've "learned" in Dyno testing, RWD Auto cars generally see 15-20% drivetrain/etc. loss by the time it gets to the rear wheels. 10-12% is very efficient (not sure if that's even possible on an Auto?).

There's a dyno sheet I recently saw that said a "general rule is to divide by .xx(number). When I did that, it came out to roughly 20% drivetrain loss.

Also, if you look at the 535i's consensus trap speed in the 1/4 mile, being around 100 MPH (give or take depending on various tests), and weighing at about 4,000 lbs, it shows that it should pin it right at around 340 HP.

A good basis I like to use is a car I used to be involved with in terms of HP/Track times, which is the SN-99 Mustang GT. It was a very pure basis of how RWHP and track times equate.

For example: The 5 Speed Manual 2004 GT made 225 RWHP on the money, which would put it at 260 HP on the money. The Auto version of the same car sucked out an additional 10-15 RWHP, putting them generally at around 210 RWHP. Those cars weighed at around 3200-3300 lbs.

The Manual GT did exactly a 14 Second 1/4 at 100 MPH, those two numbers perfectly aligning with each other as a good power/weight ratio VS track time/MPH ratio (same exact numbers the 535i generally does).

So, if you have a 3200 lb GT making 225 at the wheels with only little drivetrain loss due to being a Manual and doing a 100 MPH trap speed, and then add 700-800 lbs to it (i.e now making it a 535i) then you'd have your trap speed dropped to 92-93 MPH (1 MPH for ever 100 lbs). Therefore, in order for the 535i to recapture that 100 MPH trap speed AND taking into consideration it's an Auto tranny which means it has even more drivetrain loss, you'd need at least 80 more HP, putting it at 340 crank HP (since the GT has 260 crank HP and does the exact same numbers).

Sorry if that's confusing but hope it makes sense in terms of being a look into my crazy head. :D
Wow!! That's some hardcore rain man math.. Sorry but our cars are not pushing 340 at the crank.
 
#17 ·
Wow!! That's some hardcore rain man math.. Sorry but our cars are not pushing 340 at the crank.
OK Mr. Guru, what then do our cars put out?

A dyno of a 535i put 277 RWHP and 283 RWTQ to the wheels, straight from the showroom floor (you'll see more RWHP add up as the motor breaks in).

You'd be a one of a kind to have less than 15% drivetrain loss in an automatic, more likely 18-20%.

Also, a 4,000 lb car won't be trapping at 100 MPH with only 300 HP at the crank. Look at statistics of other cars with an *actual* 300 HP, in order to trap that high they need to weight considerably less than 4,000 lbs.
 
#10 ·
I agree with Miami. Its just a software tweak. When you're dealing with a turbo'd car a simple addition of 1-2 psi can get you that additional 15-20 HP.
And I am glad too see that smash has came to a realization of the true HP increase of the N55 BMS tune.:thumbup:
 
#11 ·
BMW Performance has a Power kit for the 3- and the X5/X6 N55 that bumps power to the 40i/N55HP level (20hp, 32lbft). Kit is an ECU tune, auxiliary water cooler and an enhanced radiator fan. There is also a kit for the TTV8 (50i, 40HP and 80lbft).

I have no idea of why this Power kit has not been offered for the F10.
 
#12 ·
I have the power up kit in my 2011 335 - although the #s are low as far as increase it completely changed the car. Torque is very low and pulls hard to redline -also seems to build boost much faster. Looking to do Dinan on new 535 when they finally come out with it.
 
#31 ·
Bwahahahahaha.

Hope you are ready to wait a long time!
 
#14 ·
so is this better than Dinan Stage 2?
 
#20 · (Edited)
So we see one or 2 dynos @260/270 and now its set in stone? Come on I know you guys have seen some high reading dynos not to mention inaccurate correction factors to show some high readings.. What do you say about those stock dynos that are in the 240s?

Plus cordoor is correct that you have to take into account our 8 speed tranny. There are many ways to push a car down the track and having proper gearing helps quite a bit
 
#21 ·
The link below calulates 4000lbs will need 313hp to attain 100mph in a 1/4 mile. Before anyone poo-poos the calculator, trust me, I don't believe in the accuracy of the dyno results either. :rolleyes:

¼ Mile Elapsed Time and MPH Calculator
 
#24 ·
Generally these calculators use measured data from thousands of data points and then apply a curve fit. As I said, I don't believe in dyno results either, or at least not rolling dynos. ;)

BTW, having a sufficient number of gears is good, but you are applying zero power while shifting, so having more gears isn't always better.
 
#26 · (Edited)
Simple solution go get your put your car on a dyno and see what the results are.. I'm sure they will be closer to 240/250 than that almighty 277 that happened once.

And here's why I am denying this so much. If our cars were 330/340 stock and we added these tunes that give us an extra 30 to 40 we'd be close to the 400 range and after owning a 360/380 e60 535 I can tell you with a tune we are not in that territory.
 
#28 ·
Yet it is widely accepted that BMW underrates their engines. The N63 regularly dynos at 385-390rwhp even though it is rated at 400. There is a reason these cars have such impressive 0-60 and 1/4 mile stats considering how bloated they are....
 
#41 ·
OK, lets say for a moment that is true, then you see how unreliable dyno's are since the results are all over the map. Just think of the 240-290 discussed here. That tells me that a technician through his adjustments can give you whatever they want.
 
#29 ·
Fact of the matter is, look at power-weight. There's NO WAY a 300 HP car will trap at 100 MPH when it weighs 4000+ lbs. It's just not gonna happen, unless you're looking at 5-10% drivetrain loss, which is not gonna happen.

I kept wondering, why would BMW underrate these engines, and my conclusion came when I got an insurance quote. This car is drastically cheaper to insure than even my 268 HP E350. I think that BMW knows if they put a 340 HP rating on an engine in so many mass produced cars sold to regular Joe/Jane's, the insurance reflection of a higher HP rating might cost them more sales than people who would buy for the extra few ponies. BMW may be an enthusiasts brand to us, and in the soul of the brand is still that, IMO, but the mass majority of their dough comes from non-car enthusiasts.
 
#30 ·
Fact of the matter is, look at power-weight. There's NO WAY a 300 HP car will trap at 100 MPH when it weighs 4000+ lbs. It's just not gonna happen, unless you're looking at 5-10% drivetrain loss, which is not gonna happen.
Exactly!
The F10 535i traps way too high for a 300hp 4100lb car.
Another comparison is the Infiniti G37, it also traps at 13.9 seconds 100mph. But it have 330hp and only weights 3700lbs.
No way our 400lb heavier car with 30 less HP can trap the same speed.
 
#32 ·
To OP question? Who knows? We'll never get a straight answer from BMW.
What all we enthusiast do know is that BMW underrates their motors and is very specific with their tune for regional and marketing reasons. That their engines are designed with plenty of "head room", is what allows the Dinan, et al, to magically pull horsepower/torque with some programming code.
Unless there is a specific induction, exhaust or valve modulating system difference between the N55 and N55HP, my guess is that it is just some proprietary ECU code reserved for premium applications (740i, 640i). So, my hunch is the horsepower/torque has always been there in the N55 but, unless your build code at the factory indicated a 740i or 640i, the ECU code that releases the extra juice is not there nor will BMW let you know how to get it.
Oh...don't get me started on why its a "x35i" in the 1,3, and 5 series but a "x40i" in the the 7 and 6 series. GOT to love them marketing guys!
 
#34 ·
And what publication would that be? Never mind. I think we have been beating this dead horse for days on end. This train de-railed from the beginning.

I wonder if I an OP can unsubscribe from his own thread. Thanks for the help Eddie, Miami and Ramble.
 
#35 · (Edited)
Here's 14.0 @ 99.3 MPH at 4007 lbs weight:
http://www.motortrend.com/roadtests/sedans/1203_2012_bmw_535i_first_test/

Here's 101 MPH trap speed at a whopping 4075 lbs:
http://www.caranddriver.com/reviews/2011-bmw-535i-long-term-road-test-review

Here's 101 MPH @ 4100 (est) lbs:
http://www.motortrend.com/roadtests...5i_mercedes_benz_e350_comparison/viewall.html

I had seen more with 100 MPH trap speeds pretty much on the nose, but haven't gotten into searching that much yet.

Here's the 277 RWHP 283 RWTQ off-the-floor 535i:
 
#36 ·
#37 ·
#38 ·
Dp
 
#40 ·
Audi and BMW (and various F/I cars I'm sure) seem to be rating their HP closer to wheel HP these days. I really think it logically would have to do with insurance rates. It won't be smart for Audi to try and sell a 380 HP low-mid line model to your average well to do businessman, as the insurance quotes would have to be quite a bit more expensive than a 310 HP rating.

Audi's S/C V6 is a beast. Talk about underrated.... I wouldn't be surprised if that thing was making close to its published HP at the wheels (which I understand is highly unlikely due to it being AWD with even more drivetrain loss, but to try and get the point across exaggeratedly, still....)
 
#50 ·
I'm trying to find stats for a 2012 Mercedes E350 which makes like 306 crank HP, probably accurately rated considering it's an N/A engine and doesn't feel as fast as a heavier 535i or Audi A6, but remember hearing that it was predicted to make mid-high 14's, at a trap of mid 90's. Again, that's a lighter car, with "apparently" more HP, trapping a good 5 MPH less. However, unfortunately I can't confirm that until I find a test link to it somewhere.
 
#55 ·
I just mentioned to Mrs D that I needed to start putting some clothing aside to start packing. I've also been watching the Munich snow forecasts, so far it's good.

... or somehow defies odds in attaining a 101 Trap Speed...
It is called a turbocharger, but Sophisto is right; there is no neeed to for me to explain mechnics to you. So believe whatever you wish, but your car is only as fast as you can drive it and you won't actually know how fast it is until you take it to the track yourself. So, I'm done with the couch racing, my 6spd/3815lb/265hp 335d vs. your 8spd/4056lb/340hp 535i - let's do it! We can meet in Indiana, Iowa, or some place like that. Your calculators will show an easy win for you, I say it will come down to the driver. :drive:

+1 to miami
 
#56 ·
Just noticed you leave in a couple of days. Did mine in October and little green with envy - wish I was going back :)

Mrs D going to let you open it up on the autobahn?
 
#58 ·
Mrs D decided it was too cold in Munich in February, so I'm on my own. As far as opening it up, I have been watching the weather forecasts closely, but the Coding Forum even closer. I really want to remove the top speed limiiter. :cry:
 
#57 ·
Interesting thread. I think measuring horsepower has its challenges even under current standards. Under new standards, as I understand it, all the belt driven accessories, emission controls etc. have to be engaged to capture the actual configuration of the motor. And this was different before 2004 because issues like the type of fuel, and the calibration of the engine controls were subject to interpretation.

Dynamometer readings at the wheels have their challenges because how much air is getting into the car with the hood up on a stationary basis, the air pressure in the tires all have an impact on the reported outcome. Considering Dunderhi's point, setting aside the actual numbers, K-A is merely capturing the impact of the turbo and other engine refinements to reported horsepower of an older Mustang. The new N55 engine performs like a NA car with more HP, recognizing that peak hp is not the sole indicator of performance.

If I can get the fun out of a car with a "reported" 100 hp and get to 60 mph in say 5.5 seconds I'm okay. Fact is the 535 performs quite well for a fairly heavy sedan. It's performance is comparable to a 1969 Mustang Mach 1 with a 428 Cobra Jet engine - shows you how far technology has come.
 
#60 · (Edited)
. Fact is the 535 performs quite well for a fairly heavy sedan. It's performance is comparable to a 1969 Mustang Mach 1 with a 428 Cobra Jet engine - shows you how far technology has come.
I actually was driven back then in one of those.
That car was spectacular, but in no way comparable to the well driveable F10.
These Mustangs were quite dangerous and hard to keep on the road.
Besides that, harsh as hell, very loud and rather uncomfortable, lacking any travelers space.
Nice cars though, for someone young and in that era.
I seldomly ever floor the accelerator of my F11 diesel, there is so much torque on a wide rev span the car is always faster than anything around. Flexibility is more of an interest in my driving than the first couple of seconds after a standstill. I hate standstills and try to forecome them as much as possible. Taking off is almost always in traffic, slower traffic, so the sprint capabilities of the car are seldomnly usable. Whilst flexibilty between 50-90 MPH is being used all the time. And at that the diesel is fabulous.
So far for this discusssion on the interesting but not very usable sprint capabilities of the F10 535.
 
#64 ·
I'm sure Dinan has put one on the Engine dyno, and has true stock numbers, but they won't release what the N55 truly put down.
 
This is an older thread, you may not receive a response, and could be reviving an old thread. Please consider creating a new thread.
Top