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View Full Version : What do you think about redlining?


AlaskaBlue
12-31-2004, 06:24 PM
Many people have different views on what will happen to an engine when it is redlined. Some say that an engine can be redlined and nothing will happed because it does not spend very much time at high RPMs. Others say that redlining is dangerous and it could potentialy blow the engine everytime one does it.

What do you think about redlining?

maurolin
12-31-2004, 09:48 PM
I have done it before on my M3 and the Ti aswell.
7300 rpms when my rev limiter hits....
not scarry.... but per my dyno readings... on an S52, after 6500 rpms there is power loss... so I set my shifting right at 6500 and if I miss... I still have some room to play safe.

hotdog19d
01-01-2005, 05:50 AM
I redline mine almost daily.....

AlaskaBlue
01-01-2005, 06:16 AM
I redline mine often too and I have a lot of miles. The car just seems like it laughs at whatever I throw at it. I love it.

JedzE36/5
01-01-2005, 08:58 PM
the redline is there to protect the motor from extreme rpms.

AlaskaBlue
01-01-2005, 10:47 PM
The question is not why there is a redline. It is whether shifting at redline will do that much damage or if it really does damage the engine at all.

aceyx
01-02-2005, 01:06 AM
it's impossible to ignore why there is a redline in the first place and then try to answer your question.

my question is why you would wait so long to shift? if you just forget every once in a while, it's likely that there's no harm done. if you're driving everywhere in first bouncing the needle, then you might grenade the motor, but if that's the case you should go buy an automagic.

AlaskaBlue
01-02-2005, 02:22 AM
All I wanted to know is what the members of this forum thought about shifting at or near redline in a drag or autocross situation. Not daily driving to school or work.

From your experiences does it hurt the engine or not with a shift point between 6250 to 7000 rpms?

maurolin
01-03-2005, 01:49 AM
just redline the bit@#! if it blows up... get an S52! HAHAHA

1996 328ti
01-03-2005, 02:33 AM
I was told redline was determined by how long the engine can sustain a certain high RPM. Redline is conservative IMHO. Nothing wrong with running up to redline although I wouldn't do it under normal driving. At the track I'm constantly at just below redline coming out of turns. Plus the car is chipped so redline is even higher. I'm not worried.

John Firestone
01-03-2005, 05:22 AM
BMW publishes both a maximum peak RPM you should never exceed (e.g. 6500 rpm for the M42/M44) and a maximum sustained RPM, a few hundred RPM lower, that you should stay below over longer periods. You shouldn't have any trouble with short excursions to either provided you properly maintain the car and first fully warm up the engine.

You may also have no problems running the engine at or near the red zone for long periods, but then again you may become one of the unlucky. A prudent reduction below the red zone of the sustained RPM between shifts will lengthen the engine's life.

ZeroG
01-03-2005, 05:56 AM
Just thought I would drop in my 2 cents.

Ok so the topc is red lining. You really need to define the term do you meab letting the car run a rev limiter wiht the needle boucing or so you mean just leting the car get a little in the red.

In my opinion for either a stock BMW cannot be reved over 7300 RPMS anymore and you risk messing up the harmonic vibration dampener on the crank and risk throwing a rod.

If you are just talking about drag racing where you only got to where the needle gets a little red you should be OK as long as you keep your engine in good working order. The main thing that I would worry about if a lifter getting stuck and bending or blowing a valve.

Now if it is Autocross you are thinking about I would say it puts a little more stress on your engine then a16 second drag race. I autocross occasionally and most of the time you never get out of second gear and find yourself maintaining 6000 RPMS for the entire minute to minute and a half lap. WHich is a lot of stress in my opinion.

-Chad

John Firestone
01-03-2005, 06:58 AM
There are plenty of people around here who maintain 6000 rpm in fifth for much longer than a few minutes. Usually nothing happens.

ZeroG
01-03-2005, 05:47 PM
There are plenty of people around here who maintain 6000 rpm in fifth for much longer than a few minutes. Usually nothing happens.
I do agree that you are right but I think the stress level at 6K in second is greater then in fifth, especially when making .5g latteral turns with all the oil in your oil pan stuck to one side of the pan.

Just a thought.

-Chad

AlaskaBlue
01-04-2005, 12:40 AM
There are plenty of people around here who maintain 6000 rpm in fifth for much longer than a few minutes. Usually nothing happens.


I didn't even know a 318 could push the car all the way to 6,000 rpms in 5th I have never had the nerve to try it. I want a better suspension first.
Is that stock or modified?


And I meant just a little in the red then SHIFT.

barische
01-04-2005, 02:19 AM
i redline when i feel like goin fast, some time i even get up to 6300, cuz i like to hear that engine scream and ask for mercy, the car is at 85,000 miles nothing happened so far, and i think that a little red lining would be fine.

floor that **** until it starts to scream for mercy, then floor it little bit more then u can shift.

AlaskaBlue
01-04-2005, 02:28 AM
I have taken mine 6500 quite a few times and I have 140,000 miles. It is like nothing, but it was driven by my dad and he swore to never take it above 3500 or 4000 RPMs. I'm could swear it runs better now than when I got the car from him two years ago.

gooten1
01-04-2005, 04:14 AM
I had the automatic before I had a manual....I topped the auto out at roughly 115-120 mph and it wasn't up to redline. I don't remember what the tach was telling me at 120 mph in the manual. Definately not redline, even though I was at the factory governing point where BMW decided not to let me go any faster. 120 is fast enough on Interstate 95 anyway. (=

John Firestone
01-04-2005, 06:22 PM
The speed limiter BMW NA put on their later 4-cylinder cars steps in and takes away the punch bowl at 190 km/h (118 mph), or around 5800 rpm in fifth on a manual transmission car with a 3.45 final ratio. The limiter has a few kilometers per hour hystersis and lets the party resume when the speed has retreated to 116 mph, BMW NA's official top speed for the cars.

A stock BMW NA car will happily charge to the engine's 6000 rpm power maximum after you remove the speed limiter. (If anyone needs to do this, just send me a PM.) Thereafter, the car slowly loses steam. You could, if you desired, push a M42/M44 coupe or four-door all the way to the 6500 rpm rev limiter in fifth, but venturing much beyond the power maximum is probably a bit impractical. The last few hundred rpm take forever to get through; you need a lot of open road; not to mention, a decently filled tank as the fuel consumption gets a bit ridiculous.

I believe BMW quoted a slightly lower top speed for a European 318ti with the same gearing which makes me think you may need a downward slope or a decent tail wind to reach its rev limit. A de-neutered BMW NA 318ti may also stop a little short (perhaps because of wind resistance?)