Engine RPM question

jhbodle · 11-26-2006, 07:23 AM

Just seen this post on M3Post whilst E90Post was offline for maintenance:

http://www.m3post.com/forums/showthread.php?t=13204

Quote:

BMW doesn't release parts that don't pass this stress-testing, but how many of us are going to drive over 30-50k miles on the new M3? If it's going to be 8500rpm by default because it needs to last, it might be possible to upgrade the software ECU to make it 9000rpm at the cost of engine life longetivity. It certainly is possible even without compromising the engine life with normal BMW engines such as the N52B30, which BMW itself has admitted can easily take about 7500rpm instead of the 7000rpm that it has been limited to in most cars.

Is the statement in bold true? Any links or proof to back that up? I take it that if the N52B30 can do it then my N52B25 can do it too. I would feel better about taking my car to the red line if I knew BMW had underrated the engine revs by that much. In 12500 miles I have only hit the redline once and that was because I wasn't paying attention...

elalona · 11-26-2006, 08:26 AM

""""BMW doesn't release parts that don't pass this stress-testing"""

I dont think so ...

espo · 11-26-2006, 09:54 AM

I would say any production part on a car is going to be limited at less than the designed numbers just to be safe.

Jaws · 11-26-2006, 10:10 AM

There's no problem in taking a broken-in, warmed up car to redline. Enjoy your BMW.

Jaws · 11-26-2006, 10:19 AM

Quote:

Originally Posted by NaViT

that statement is just dead wrong...

Which statement?

mali_panj · 11-26-2006, 10:37 AM

if the engine is properly warmed, anything that goes under whiteline and
by that I mean up to 6999 rpm's, just go and rev it

if you wanted to drive slowly and not rev it to the red line, why didnt you by
VW or Mercedes? those are great slow cars

jhbodle · 11-26-2006, 12:02 PM

Well it's not like I don't go over 3000rpm or anything, I have a self-imposed rev limit of 6500rpm because I like to look after my cars. I read a magazine article that said that changing gear just a few hundred revs below redline means a lot less wear on your engine.

Leonardo629 · 11-26-2006, 01:03 PM

Most "wear" occurs when you start your baby up 6am in the morning....

If your engine is all warmed up, and your motor oil in good condition, it'll protect your motor...even if you redline all day long.

Quote:

Originally Posted by jhbodle

Well it's not like I don't go over 3000rpm or anything, I have a self-imposed rev limit of 6500rpm because I like to look after my cars. I read a magazine article that said that changing gear just a few hundred revs below redline means a lot less wear on your engine.

FirstClass · 11-26-2006, 01:21 PM

Quote:

Originally Posted by jhbodle

In 12500 miles I have only hit the redline once and that was because I wasn't paying attention...

/slap

Seriously though, its your car do what you want but its a huge waste to buy a BMW and not use it to its full potential. (I assume by "hitting" redline you mean shifting just shy of the limiter, not actually bouncing off the limiter)

ward · 11-26-2006, 01:33 PM

Quote:

Originally Posted by jhbodle

Just seen this post on M3Post whilst E90Post was offline for maintenance:

http://www.m3post.com/forums/showthread.php?t=13204

Is the statement in bold true? Any links or proof to back that up? I take it that if the N52B30 can do it then my N52B25 can do it too. I would feel better about taking my car to the red line if I knew BMW had underrated the engine revs by that much. In 12500 miles I have only hit the redline once and that was because I wasn't paying attention...

it's called a "saftey factor" parts are engineered to be stronger than what they're rated for

if you buy a ladder rated for 250 lbs, and take 300 lbs up there it won't break, but if you go too far it will break.

it the redline is 7000, it's very possible and reasonable to expect the engine not to be compromised by going to 7500 revs, but don't expect the factory to help pay for damages caused by that action.

jhbodle · 11-26-2006, 01:39 PM

Quote:

Originally Posted by FirstClass

/slap

Seriously though, its your car do what you want but its a huge waste to buy a BMW and not use it to its full potential. (I assume by "hitting" redline you mean shifting just shy of the limiter, not actually bouncing off the limiter)

Point noted. I just get paranoid about thrashing something I paid £30,000 for. I guess it's time to make that engine work!

Out of interest, just before the redline there are 3 or 4 small white lines on the tacho - what do they signify? Is it a warning that you are approaching the redline? Or a sign showing the engine does not make any more power past this point (I notice the diesels have a much larger area of white lines on their tachos) or is it something else completely?

SROC3 · 11-26-2006, 04:41 PM

just don't bounce off the rev limiter and you'll be fine. Engine tolerances are posted above below the actual threshold to maintain longevity. In one respect, the engine may very well be able to take a beating and keep slapping past the 7000 mark, but why risk it when it will be counter productive to acceleration at that rev range anyway. Just shift at 6800 and occasionally at 7000 if you like. Keep in mind that the torque starts to kick in at 1400 rpm (if I'm not mistaken). This is not a Honda - which requires you to activate the VTEC at a high rpm range.

Driv3r · 11-26-2006, 04:45 PM

i knew this all along, i heard it form someone who was with BMW a while ago...

jhbodle · 11-27-2006, 12:10 PM

Thanks for the input. I should know how well built these engines are really - there's a guy on the BMWLand forum in the UK that has upped the rev limit on his E46 325i (lower 6500rpm redline remember) to 7200rpm. He uses the extra revs to lower his quarter-mile time.

SoYank · 11-27-2006, 12:28 PM

Quote:

Originally Posted by jhbodle

Point noted. I just get paranoid about thrashing something I paid £30,000 for. I guess it's time to make that engine work!

Out of interest, just before the redline there are 3 or 4 small white lines on the tacho - what do they signify? Is it a warning that you are approaching the redline? Or a sign showing the engine does not make any more power past this point (I notice the diesels have a much larger area of white lines on their tachos) or is it something else completely?

I thought they were 'hundred' marks but I just checked and on mine there are five of them between 6500 and 7000. So, I'd surmise they are there to warn you you're approaching the limit.

PatsE92 · 11-27-2006, 04:53 PM

Having come from and S2000 with an 8k redline I can attest to the fact that running it up to redline is not a bad thing but bumping it off the "limiter" repeatedly is disconcerting to say the least. I have not run my E92 past 6k yet but am looking forward to it. Guess I need to see if Modifry has a shift beeper mod for my 3er huh?:rocks:

11-26-2006, 08:26 AM	#2
elalona Private First Class 19 Rep 120 Posts Drives: E39-03' E92 335 since 11DEC06 Join Date: Dec 2005 Location: Emirates-DXB iTrader: (0)	""""BMW doesn't release parts that don't pass this stress-testing""" I dont think so ... __________________ BMW
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11-26-2006, 09:54 AM	#3
espo Captain 12 Rep 715 Posts Drives: 2014 M235i Join Date: Sep 2005 Location: Sugar Land TX iTrader: (0)	I would say any production part on a car is going to be limited at less than the designed numbers just to be safe. __________________ E46 325xi Oxford Green/Sand Leatherette/Myrtle Wood Auto ZCW - Retired E90 330xi Mystic Blue/Black Leather/Aluminum 6sp Manual ZSP/ZPP/ZCW/CA - Retired F22 M235i Mineral Gray/Red Leather/Aluminum 6sp Manual ZPP/ZTP
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11-26-2006, 10:10 AM	#4
Jaws Lieutenant Colonel 45 Rep 1,738 Posts Drives: 2006 325i mt Join Date: Aug 2006 Location: Edmonton iTrader: (0)	There's no problem in taking a broken-in, warmed up car to redline. Enjoy your BMW. __________________ 2006 325i - Sparkling Graphite 2000 S2000 - New Formula Red 2007 Chev Silverado crew cab Z71
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11-26-2006, 10:37 AM	#6
mali_panj Enlisted Member 15 Rep 49 Posts Drives: BMW E90 330i Join Date: Nov 2005 Location: Zagreb/Croatia iTrader: (0)	if the engine is properly warmed, anything that goes under whiteline and by that I mean up to 6999 rpm's, just go and rev it if you wanted to drive slowly and not rev it to the red line, why didnt you by VW or Mercedes? those are great slow cars
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11-26-2006, 12:02 PM	#7
jhbodle Captain 146 Rep 898 Posts Drives: F90 M5 Join Date: Mar 2005 Location: UK iTrader: (0) Garage List 2007 E92 335i M-Spo ... [10.00] 2005 E90 325i SE (E ... [0.00]	Well it's not like I don't go over 3000rpm or anything, I have a self-imposed rev limit of 6500rpm because I like to look after my cars. I read a magazine article that said that changing gear just a few hundred revs below redline means a lot less wear on your engine.
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11-26-2006, 04:41 PM	#12
SROC3 The limit of adhesion is my home. 1702 Rep 3,778 Posts Drives: Like a Boss. Join Date: Sep 2006 Location: three.one.zero iTrader: (1)	just don't bounce off the rev limiter and you'll be fine. Engine tolerances are posted above below the actual threshold to maintain longevity. In one respect, the engine may very well be able to take a beating and keep slapping past the 7000 mark, but why risk it when it will be counter productive to acceleration at that rev range anyway. Just shift at 6800 and occasionally at 7000 if you like. Keep in mind that the torque starts to kick in at 1400 rpm (if I'm not mistaken). This is not a Honda - which requires you to activate the VTEC at a high rpm range. __________________ 2019 X3 xDrive30i Glacier Silver \| Cognac w/ Fine Cove \| MSport \| Premium \| Dynamic Handling PKG \| Drive Assist \| HK w/ Bavsound Upgrade \|
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11-26-2006, 04:45 PM	#13
Driv3r Colonel 177 Rep 2,355 Posts Drives: 2006 E46 M3 ZCP Join Date: May 2005 Location: Miami Beach, FL iTrader: (8) Garage List 2006 325i [0.00]	i knew this all along, i heard it form someone who was with BMW a while ago... __________________ 2006 E46 M3 ZCP 6SPD-Interlagos Blue - 6SPD - SSK - AA Headers -AA Tune - Navigation w/ Splashscreen Mod - 3M Crystalline Series 60 - Carbon Splitters - Swissvax Treated - Bridgestone 2012 Yamaha FZ8 - Matte Black/Grey - Michelin Pilot Pure 2CT - Vortex Rear Sets - Yoshimura R-77D & Fender Delete - Spectro Race Oil - GP Reverse Shifting
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11-27-2006, 12:10 PM	#14
jhbodle Captain 146 Rep 898 Posts Drives: F90 M5 Join Date: Mar 2005 Location: UK iTrader: (0) Garage List 2007 E92 335i M-Spo ... [10.00] 2005 E90 325i SE (E ... [0.00]	Thanks for the input. I should know how well built these engines are really - there's a guy on the BMWLand forum in the UK that has upped the rev limit on his E46 325i (lower 6500rpm redline remember) to 7200rpm. He uses the extra revs to lower his quarter-mile time. Last edited by jhbodle; 11-27-2006 at 12:26 PM..
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11-27-2006, 04:53 PM	#16
PatsE92 Private 4 Rep 99 Posts Drives: 2010 E92 M3 Join Date: Oct 2006 Location: Lafayette, LA iTrader: (0)	Having come from and S2000 with an 8k redline I can attest to the fact that running it up to redline is not a bad thing but bumping it off the "limiter" repeatedly is disconcerting to say the least. I have not run my E92 past 6k yet but am looking forward to it. Guess I need to see if Modifry has a shift beeper mod for my 3er huh?:rocks: __________________ ____________________________________________
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