tuffluck

i see a lot of topics that address the question, "which one should i get, the 530i or the 545i??" and i thought i would share my perspective when i, too, was looking and comparing bmw's.

for starters, the reason i am posting this is because when i purchased my 2007 530i (and please realize for this demonstration i am comparing the 255hp version of the 530i only), i was pretty impressed with it's power compared to a 525i. then immediately after i test drove the 530i, i got to drive a 2010 535i with the M package. we did WOT in both cars from 0-90mph, and i can honestly say that in the 10 minute window of driving both cars, i hardly noticed any power difference. my girlfriend concurred. i was astonished. also i came from a previous 360-hp muscle car that was very fast, so i can tell the differences between fast and not-as-fast.

so i decided to look into this a bit further and came across some interesting information. i don't think a lot of people realize the effects weight have on cars. the online consensus is that the calculation for 100lbs is that it equals 10hp. so for every 100lbs of your car's weight, you are sacrificing 10hp. essentially a 3500lb car at 350hp versus a 3000lb car at 300hp would prove to have a complete tie in a race assuming all other factors remained static.

so i went and did my research, and with a simple lookup on yahoo! autos, this is what i found to make these calculations that follow:

Car, Weight, HP, HP Difference, Weight Difference, HP Differential, New HP Difference
2007 530i, 3494, 255, 0, 0, 0, 0
2007 550i, 3814, 360, 105, 320, 32, 73
2004 545i, 3748, 325, 70, 254, 25.4, 44.6
2008 535i, 3704, 300, 45, 210, 21, 24

that table looks funny, but essentially the addition of extra weight and horsepower on the 5-series after the 530i makes for an actual horsepower difference of ~24hp in the 535i, ~45hp in the 545i, ~73hp in the 550i.

also, in my experience in the modification of my 360-hp muscle car, it takes a good 30hp difference at least to notice an obvious difference in power, which explains why the 530i and the 535i felt nearly identical to me in the 10 minute window i got to test drive both. i think the 545i would feel a bit different than the 530i, but not much different than the 535i. and i think the 550i would feel different over the 530i and 535i, but not necessarily the 545i. not to mention the price difference when comparing a 550i to a 530i, the dollar per horsepower goes way up. not that it means anything other than just a rough diagram for the comparison of the 5-series.

hope i don't catch fire for this, haha...i just thought it was interesting. thoughts?

Howitzer

Goddamit, I'm going on a diet.

sdg1871

I keep promising to myself that I'm going on one. But it never seems to happen.

PROE60

Thank you for making me feeeeellllll so Great that I got a 07' 530I.

EBMCS03

That's it! I'm tossing out those floor mats! They weigh at least 10 lbs

xenonrider

hard to beat the growl, feel and the torque of a V8 though... driving a car is not always about the numbers

one factor you may not have considered is torque. the 530 is rated at 220, while the 530 is rated at 300, 545 at 330, 550 at 360. for normal driving, the torque is what gets you going. if you look at the HP numbers at typical driving RPM ranges (for me it's 2500-4000RMP), i'm sure you find the HP differences to be more significant.

having said that, the 530 does look like the more practical choice....

ObD

Need the torque numbers in that table. The I6TT is a night and day difference from the NA I6 so disagree with you. The NA I6 is gutless. So is the I8 from the M3 ...less torque than the TT.

Howitzer

You're right. My car off the line is a fartwagon. Only when it gets to 30mph or more will it kick in. The only solution is an ESS Supercharger! weeeee.

tuffluck

you're right, torque is important. my previous car dyno'd 335 rear wheel torque, which i suppose is somewhere around 375 flywheel torque, and it was beastly. there is an obvious difference in the 530i, though the 530i still weighs more. but, no matter the numbers and item you are comparing (horsepower/torque), all the differences are relative to the others.

what is the 535's torque numbers? i just urge anyone (that doesn't own a 535i...i don't want people to hate me!) to go test drive a 530i and a 535i and see if you can noticeably tell a difference in power. the 535 has a little bit more punch down low (higher torque), but it's very insignificant. this of course comparing stock to stock.

put a 530i with almost no fuel in the tank up against a 535i with a full tank of gas. i'd like to see who would pull on who.

Michiganmike

I agree that torque at a given RPM is often more important than maximum HP in how fast a car feels. The 550 earns points for the maximum torque, but the 535 delivers its maximum 300 lb-ft of torque from 1400 to 5000 RPM. In comparison, the normally aspirated 530 delivers its 220 lb-ft maximum torque at 2750 RPM. Even at WOT I would expect the difference in torque to be apparent between the 530 and 535. The 35% difference in maximum torque is large compared to a 6% weight difference. In normal driving the greater torque at low RPM from the 535 will be even more apparent. BMW rates the 0 to 60 mph time at 5.7 seconds for the 2010 535i with the automatic compared to 6.4 seconds for the 2007 530i. You will need more than the difference in weight due to a full tank of gas to close this gap.

In HP comparisons, keep in mind that several sources (including Dinan tests) have confirmed that the 535i in stock form produces more like 320 to 330 HP than the rated 300 HP. It has been speculated that BMW was exceptionally conservative in rating the horsepower from the 535 to maintain the desired interval behind the 360 HP of the 550. However, a difference of only 0.2 second in BMW's own specified 0-60 mph times between the 2010 535i and 550i suggests the difference in engine output is not that great. In addition, the difference in BMW's specified 0-60 time actually shrinks to 0.1 second with a 535i xDrive compared to a 550i (no xDrive available in the E60 model) despite the additional weight because of better traction. While HP and weight are important, there are other parameters that need to be considered.

I am glad that tuffluck likes the E60 530i. I enjoyed my E39 530i which had even less horsepower, but also a little less weight. However, I would not recommend any stock 530i race a 535i for pink slips.