Raising rev lim to 8600

[Ateam]

I agree it sounds nice, atleast in theory in order to truly be able to take it to 8400 without getting fuel cutoff. In first and 2nd its almost a crap shoot if you are shifting, as to where above 8k you actually shift. It would be nice to have more leway so you can hit 8400 consistently and not have fuel shutoff.

This is where I hate to say but I missed the steptronic autobox. If you were in manual mode it simply would shift at redline for you if you did not shift early enough so there was no fuel cutoff. Maybe for the manuals there was. I dont see why the dct cannot do this instead of cutting off fuel

[MysticBlue]

Originally Posted by Ateam

This is where I hate to say but I missed the steptronic autobox. If you were in manual mode it simply would shift at redline for you if you did not shift early enough so there was no fuel cutoff. Maybe for the manuals there was. I dont see why the dct cannot do this instead of cutting off fuel

Uh, put it in D mode and it will. I run in S mode almost exclusively, but D mode is good for a WOT run up through the gears situation. It's just a backhand bump of the stick away, and going back to S mode is just a paddle shift away. In other words, it's very easy to go from S mode to D mode, and will then do what you describe. And it is beyond easy to go from D mode back to S mode when you want to... just do what you would have done anyway; shift, and it shifts and is back in S mode. I keep D mode in level 5 just for this reason, so it is the most aggressive, and if you accelerate with the accelerator all the way to floor, including pushing the indent, it will hold until redline before it shifts for you.

[Ateam]

Originally Posted by MysticBlue

Uh, put it in D mode and it will. I run in S mode almost exclusively, but D mode is good for a WOT run up through the gears situation. It's just a backhand bump of the stick away, and going back to S mode is just a paddle shift away. In other words, it's very easy to go from S mode to D mode, and will then do what you describe. And it is beyond easy to go from D mode back to S mode when you want to... just do what you would have done anyway; shift, and it shifts and is back in S mode. I keep D mode in level 5 just for this reason, so it is the most aggressive, and if you accelerate with the accelerator all the way to floor, including pushing the indent, it will hold until redline before it shifts for you.

I know you can do it in D which is great and not a big deal you cannot do it with S but I was just curious why they would not offer that given it clearly is capable of doing it in D mode. Not a huge deal but would be nice to just stay in S and be able to redline the gear if you want without "planning" for it and shifting to D.

[Mahmood07]

Originally Posted by Ateam

I agree it sounds nice, atleast in theory in order to truly be able to take it to 8400 without getting fuel cutoff. In first and 2nd its almost a crap shoot if you are shifting, as to where above 8k you actually shift. It would be nice to have more leway so you can hit 8400 consistently and not have fuel shutoff.

This is where I hate to say but I missed the steptronic autobox. If you were in manual mode it simply would shift at redline for you if you did not shift early enough so there was no fuel cutoff. Maybe for the manuals there was. I dont see why the dct cannot do this instead of cutting off fuel

Thank god it doesn't autoshift in S Mode! That would be no fun. It's nice to have to shift exactly at redline with consequences (fuel cut off) if you don't hit it just right. Makes you feel like a racing driver

[klammer]

Originally Posted by Mahmood07

Thank god it doesn't autoshift in S Mode! That would be no fun. It's nice to have to shift exactly at redline with consequences (fuel cut off) if you don't hit it just right. Makes you feel like a racing driver

Exactly... This adds to the control of the car and why this tranny is definitely NOT an auto...I would hate this feature on track, to be constantly shifting for me at redline??? No thanks. I take my racecars with ME as the driver.

[bigjae1976]

Originally Posted by MysticBlue

So tell us, specifically, what is the difference between early models and later models, and when, specifically, did this change take place?

Some Early production cars had a bearing issue with the engines.

[MysticBlue]

Originally Posted by bigjae1976

Some Early production cars had a bearing issue with the engines.

Do we know the production date of the change?

[MysticBlue]

Originally Posted by klammer

Exactly... This adds to the control of the car and why this tranny is definitely NOT an auto...I would hate this feature on track, to be constantly shifting for me at redline??? No thanks. I take my racecars with ME as the driver.

+1 I tried using D mode on the track once, just out of curiosity. A couple of laps. Hated it. There is a short piece between corners where if I hit just right I would hit redline in third right at the beginning of the braking point and don't want it shifting into 4th, but it did in D mode. Not good.
But if you're just playing drag racer, going in a straight line fast, D works ok for that. Not as much fun, but it gets it done.

[The Flying Scotsman]

Originally Posted by MysticBlue

So tell us, specifically, what is the difference between early models and later models, and when, specifically, did this change take place?

Bmw has made over 200 changes to the M3 from 08 to current. One of the issues that they had was with the valve springs. Bmw did not specify if it was a problem with the spring itself or if there was a weak retainer. Either way, the valve was dropping in to the piston and causing major damage to the motor. Bmw had the same issue with the 95 M3. By raising the rpm's on the stock motor, you will be more likely to cause this issue. More rpm's = more strain on the motor.

This issue was found in some 2008 models. I am not too sure of the exact dates.

My point before was that the car will not make more power with a raised rev limit vs. the stock rev limit at the same rpm! I understand that with a higher shift point, the next shift will fall at a higher rpm. This may possibly give the car an additional 8 whp like "Mike Benvo" suggests because the higher the rpm's rise, the more power the car makes, generally speaking. However, this will not give any more power than a car that shifts at 8,300 rpm's at the same rpm!

You have to ask yourself if this possible 8 whp is worth anything either on the street or on the track. I would rather know that my rpm has never gone above the stock 8,300 just incase I ever have any warranty issues!

[bigjae1976]

Originally Posted by MysticBlue

Do we know the production date of the change?

Not sure of the details...I think it was limited to 2008 model year. Not that an 08 M3 is a ticking time bomb. I've only seen that issue pop up 2 times on this forum. Blown motors are rather rare here.

If it were me, I'd think twice about raising the limit on a relatively new engine. Let BMW sort out the minor issues first. At this point, the S65 is about as good as it is going to get from the factory. So I don't see why this would be an issue unless BMW built not margin for safety in these engines.

[persian54]

Originally Posted by Mike Benvo

An example of this in a different instance, is changing the cold start rev limits. In stock form the car will only rev to around 6.5k dead cold, but this can be changed in the code to 8,600.

Thanks for the info Mike

What would one define as unsafe operating temps?

I only use my increased limiter at the track, and that's in rare cases where I'm on a long straight before a turn, and I don't want to upshift to 4th, so I use that extra RPM limit so the car can go to ~8600.

Temps are usually around the 3rd oil temp mark... which I think is 245 degrees?

[IMG]

Originally Posted by Mike Benvo

Yes this car will make more power just from a rev limit change. This is due to the design of the engine/vanos system, etc.. You'll make about ~8 whp more (this depends on conditions of course).

Looking in the Dyno DB. 450 entries. Only 32 entries made max HP at 8400 RPMs. All others had peaked before 8400 and were falling. Raising the redline on these 418 other cars will not increase their power, and may not even raise power on the 32.

Originally Posted by Mike Benvo

The RPM changes are actually quite significant because that extra 300 RPM puts you 300RPM higher after the shift, so the car is making more power after each shift than it would had it shifted at the stock limit.

Not exactly right...Mike. The RPM drop depends on what gear you're in. On a DCT, raising the redline only gives you between 125 - 165 RPM drop difference.

Originally Posted by Ateam

I know you can do it in D which is great and not a big deal you cannot do it with S but I was just curious why they would not offer that given it clearly is capable of doing it in D mode. Not a huge deal but would be nice to just stay in S and be able to redline the gear if you want without "planning" for it and shifting to D.

ESS DCT software can add auto shift at redline in S6 Mode.

Originally Posted by bigjae1976

Some Early production cars had a bearing issue with the engines

Main bearings changed in October 2008.

Originally Posted by M3*GaryShrig*M3

One of the issues that they had was with the valve springs. Bmw did not specify if it was a problem with the spring itself or if there was a weak retainer.

I think this may be a myth. I'm looking at the BMW valve train parts. None of the parts or part numbers have changed since the car's introduction. That includes the valve spring, retainers, guides, seals, and valves themselves.

Regardless, you make a very good point. Incrased RPM with weak valve springs (or heavy valves) can cause valve float, which itself can cause a piston to crash a valve. For anybody worried about this, there are now aftermarket high performance valve
springs available.

[GIdriver]

Originally Posted by lm1z

I swapped out the S65 for a battery. I have no revs.

[pbonsalb]

For cars under warranty, does the computer store the peak rpm so warranty would be voided by an 8600 rpm limit if there was an engine problem. Is this correct?

[klammer]

Also, more revs on an NA engine gives one a larger margin of control. Easier to control speed (mid corner corrections, on/off throttle oversteer). It's not really about power, at least not for me, and that's why this car is soooo awesome... The level of control I have over it

[The Flying Scotsman]

Originally Posted by pbonsalb

For cars under warranty, does the computer store the peak rpm so warranty would be voided by an 8600 rpm limit if there was an engine problem. Is this correct?

Yes! Bmw "could" void your warranty if they ever find out that you have ever rev'd past the stock 8,300 rpm's or if you have ever been past the stock limited 155 mph.

The Bmw computer will store all this information such as when you went over and for how long.

[pbonsalb]

They may view it as a mechanical over-rev since there is no other explanation if the software is stock. Than means a voided warranty. These days, it seems they are looking to deny more than to allow. Hopefully nothing goes wrong, but you are on the short end of the stick trying to argue to BMW that over-revving to 8600 rpm is in now way responsible for the engine failure for which you want coverage. I would probably stick to 8400 while the warranty is in effect for this reason. I use 7200 rpm on my E36M3 versus the stock 6750 rpm, but it is out of warranty.

[heart_doctor]

Originally Posted by stega

Huh 9800??? You sure about that? What tune would that be?

That would be from a company called BS. 😃

[BPMSport]

Originally Posted by img

Looking in the Dyno DB. 450 entries. Only 32 entries made max HP at 8400 RPMs. All others had peaked before 8400 and were falling. Raising the redline on these 418 other cars will not increase their power, and may not even raise power on the 32.



Not exactly right...Mike. The RPM drop depends on what gear you're in. On a DCT, raising the redline only gives you between 125 - 165 RPM drop difference.

You are right about the RPM drop - it depends on the gearing multiplication.
But point remains that you will be higher up in the rev range and the car will be making more power than it would at a lower RPM (post shift). The real world performance difference would be most significant in higher gears.

As far as peak HP at higher RPM, I should have mentioned one other thing besides the redline change itself - There also should be a couple changes to the VANOS maps as well (particularly the metadata / RPM scaling) for max gain on top. Otherwise it may not maintain the power curve.


The car will store your max rev along with other information about it (throttle position, kg/h, etc..) It also stores how many times you've hit redline, for how long, etc.. Unfortunately this can't be cleared like it can on the E39 M5/E46 M3. I'm sure at some point in time it will be clearable, but I don't know of anyone at this point in time that has the tools to pull it off since one side of the ECU is locked from BDM access. You'll have better luck with a warranty claim with a DCT car over a 6MT. I've seen stock DCT cars record 8,500, even though the redline is lower.

[Ateam]

Originally Posted by Mike Benvo

You are right about the RPM drop - it depends on the gearing multiplication.
But point remains that you will be higher up in the rev range and the car will be making more power than it would at a lower RPM (post shift). The real world performance difference would be most significant in higher gears.

As far as peak HP at higher RPM, I should have mentioned one other thing besides the redline change itself - There also should be a couple changes to the VANOS maps as well (particularly the metadata / RPM scaling) for max gain on top. Otherwise it may not maintain the power curve.


The car will store your max rev along with other information about it (throttle position, kg/h, etc..) It also stores how many times you've hit redline, for how long, etc.. Unfortunately this can't be cleared like it can on the E39 M5/E46 M3. I'm sure at some point in time it will be clearable, but I don't know of anyone at this point in time that has the tools to pull it off since one side of the ECU is locked from BDM access. You'll have better luck with a warranty claim with a DCT car over a 6MT. I've seen stock DCT cars record 8,500, even though the redline is lower.

I did not know it could store anything in storage that cannot be erased. So why doesn't bmw use this to store other codes in the turbo models to identify a tune and flag it? Its the people cranking up boost and adding 100hp to a stock engine that is really causing bmw problems. The tunes on the s65s are likely not causing much damage at all. However they always try things to prevent tuning yet it seems they are capable of recording it and keeping it locked to tuners. any idea why they don't do this?

[BPMSport]

Originally Posted by Ateam

I did not know it could store anything in storage that cannot be erased. So why doesn't bmw use this to store other codes in the turbo models to identify a tune and flag it? Its the people cranking up boost and adding 100hp to a stock engine that is really causing bmw problems. The tunes on the s65s are likely not causing much damage at all. However they always try things to prevent tuning yet it seems they are capable of recording it and keeping it locked to tuners. any idea why they don't do this?

BMW did incorporate a few things into the MSD81 ECU's on the 335 to try and detect piggyback units. Having the DME itself flashed is a different story. I haven't read freezeframes from a 335 so I am not sure what it records. Definitely max rev and max speed, not sure if it logs boost.

As far as safe tunes on the M3 - yes, most of them are safe. However, any competitent tuner would be able to make a file for your engine which could cause serious damage. It comes down to minimum timing advance and knock strategy. Running/Forcing minimum timing and removing knock and misfire detection could be a recipe for disaster.

Many tuner's don't know where the minimum timing maps are. In this case, you can have higher ignition aims/targets in the software without actually hurting anything, it will just not achieve the targets set in the code. Serious damage can be done when minimum timing is advanced too far and knock strategy is changed.

Rest assured that all software from me does not change the factory knock settings at all. All tuners can make considerably more power on these cars by changing knock strategy in conjunction with timing changes. It gives you a dyno queen, but at what expense? It's better to play it safe than sorry.