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Hi everyone...
Installing an Auto Blip on my '02 M5 and cant seem to find where the wiring connects to the pedal position. I looked all around under the dash and cant find any leads from the linkage. Could it be the pedal position wiring is on the engine/firewall side? Thanks for any insight you have.
 

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auto blip? how? are you retrofitting from newer BMW with this feature?

the E39 M5 uses a pot sensor, which may not compatible. See this...
 

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I think he is referring to this AUTO-BLiP Intelligent Downshifts | Auto Blip. RonRace, please confirm.
To each their own, but from what I can see on their website this will not be anywhere near what the factory rev matching is. This device adds a fixed throttle blip when clutch and brake and pressed together. The factory rev matching system actually monitors engine RPM and transmission input shaft RPM and matches those. This device has no connection to your transmission. However, I can see this having some potential utility on the track.
I've actually thought about how one can add rev matching to our cars and I believe that it is impossible. Even if one can make clever electronic devices, you would need to know the RPM of the transmission input shaft as well as the engine. The engine is easy, you can tap into the crankshaft position sensor, but there is no gear position sensor or transmission input sensor in our cars, so there is no signal for that.
 

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Discussion Starter #5
I think he is referring to this AUTO-BLiP Intelligent Downshifts | Auto Blip. RonRace, please confirm.
To each their own, but from what I can see on their website this will not be anywhere near what the factory rev matching is. This device adds a fixed throttle blip when clutch and brake and pressed together. The factory rev matching system actually monitors engine RPM and transmission input shaft RPM and matches those. This device has no connection to your transmission. However, I can see this having some potential utility on the track.
I've actually thought about how one can add rev matching to our cars and I believe that it is impossible. Even if one can make clever electronic devices, you would need to know the RPM of the transmission input shaft as well as the engine. The engine is easy, you can tap into the crankshaft position sensor, but there is no gear position sensor or transmission input sensor in our cars, so there is no signal for that.
Yes sir, I have installed an Auto-BLiP to my GT3 and love it. You are correct, it is NOT rev matching, it is simply a throttle blip, but you can adjust timing and duration of the blip. Have a unit for my M5, but the throttle connections are a challenge (which wires) and not easy to get to as you know.
 

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I’m curious as to what the point is? Not being snarky it’s an honest question- rev matching is simple under braking (or downshifting with no brakes) using your foot, why would you want an automatic blip on the throttle that might not match rpm for the next gear? Am I missing something?
 

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There are 2 reasons that I see for automatic rev matching, it is easier and better than any driver. The easier part is personal call. However, the computer is better than you are at getting the revs to match precisely. Now this won't work with this system because it is not monitoring the transmission input speed, but in factory systems it is always a perfect blip. Actually this is something that I've noticed on the e39m5. See attached photo of the transmission bell housing. There is a casting for a speed sensor (circled in red) at the bottom, although I am not aware of BMW ever actually making a model of this transmission with a sensor in this spot. I searched. Any machine shop can drill this hole out and it probably aligns with a gear on a countershaft (looks like it would be 5th gear), and that gear is then probably used as a reluctor wheel to measure the transmission input shaft speed. Using this info, and the engine RPM, is what the computer needs for rev matching. I think that the only way to make a factory-like rev matching system is to drill out this hole, find a hall-effect sensor that fits this. Then take this signal and compare it to the signal from the crank position sensor and create a correlation map. Then create a digital device that taps into the pedal throttle signal to match the engine speed to the speed of this transmission input sensor when the clutch pedal is pressed and the vehicle is moving at a minimal speed. I am sure that somebody can do it, but this is far beyond my skill level. This is a true engineering project. Any takers?
 

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I was hoping it would work, I love it in my F10 M5 manual. To lazy now to auto blip.
 

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seems like alot of work for not that much gain and potential for something to go awry is high. What if it blips incorrectly and causes an accident or engine to over rev?
 

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It is a lot of work and requires real engineering and way above my abilities. I just wanted to note that the transmission has a space for a potential sensor, so I am guessing this was considered as a future option when the transmission was being designed.

To address mmzcee's comments, I don't think that the device can over-rev the engine. The device would simply "push the throttle" pedal for the driver, but electronically. Lets say that it floors the pedal (which is the worst it can do) when the clutch is depressed. The engine woudl then rev to the red line, but the main computer would not allow it to rev higher. I think that the only way to over-rev our engines is mechanically by putting it into too low of a gear for the specific speed. You can do that with a late model car with factory rev match too. Therefore I see limited opportunity for engine damage from this device. The big challenge is just the engineering, making the device, coding, etc.. If someone is really capable of doing the electronics, I am happy to volunteer my car as a test bed. I have a spare transmission which I can remove the bell housing, take to a machine shop and have them drill out the hole, then find a fitting hall effect sensor and install it. from there on it is all electronics, which is where I don't have much expertise.
 

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One of the reasons I love driving a stick is to heel and toe, been doing it on the track for 2 decades though so it’s second nature, I find it fun. Never botched a downshift and caused wheel spin or a hard drop on the clutch entering a corner, not sure how much more perfect one needs to be?

I get it on the rev matching; have driven many cars with it, it’s a nifty gizmo but at that point I rather have a paddle shift and 8 gears (that’s just me though).

I asked about throttle blip, not matching revs; if I need 6k going into second and the blip has me at 4, or I need 3 and the blip has me at 6 that’s not gonna go well, no way to control the rpms. Again I get the rev matching, just not the blip. Seems like a lot of work for something you can do yourself.
 

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I have to agree with Matt. Some pride developed in doing a good throttle blipping downshift.

Am I the only one that sees the irony of someone willing to drive a MANUAL transmission but needs AUTO BLIPPING to help on the downshift????

Each to his/her own.

Regards,
Jerry
 

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@mattparsons and @gsfent, I like you guys, your are my kinda of people, this is very much my school of thought. There are literally thousands of newer cars that have this type of feature (or similar) to help do all of the driving for you. The whole appeal of an E39 M5 in today's world (for me) is it's LACK of all that stuff, as it's a very rare holdout that ALLOWS you to to actually control things yourself. All fine and good if you want those driver assists, but that's what a Kia Stinger is for. . .
 

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Looks like there are two topics being discussed here, the WHY and HOW of auto rev matching. I think the WHY question is a matter of personal preference, some people like the more "analog, I'll blip it myself" approach, and others may enjoy their car more with the auto rev matching feature. We aren't going to reach a unanimous agreement here on this topic. I think a better use of this thread would be to focus on HOW, for those that are interested. For me personally, I am happy rev matching myself, but I also like the idea of tinkering with stuff and adding new functionalities. I think that the mechanical part of this problem (adding a speed sensor on the input shaft) is relatively easy. The challenge is developing an electronic system that controls this.
 

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Well on that point I agree too- it’s fun to overcome the challenge of installing something to customize your car the way you want. I personally feel like a blip system is not suitable, rev matching is. If you could get true rev matching to work that would be a real accomplishment, I hope you can succeed!

If you do I’d be first in line to take a ride to see it in action, I love that people can personalize their cars the way that’s right for them, and can appreciate it (even if it’s not right for me). Good luck and sorry to take it off the rails with the why as opposed to how- I was really more interested in the merits of the blip system and if it actually works (vs the true rev matching).
 

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One other 'challenge' to consider, the auto-blip says it opens the throttle when both the clutch and brake are depressed. . . but I personally do that not infrequently when upshifting also, like when overtaking on a 2-lane road, and also in the event of Trouble! when both feet go in. So might need some consideration/tuning such that it doesn't activate when you DON'T want it to.
 

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I see 3 limitations of the auto-blip system currently for sale. First, the amount of "blip" is preset, so it can't automatically adjust for a single gear downshift vs. 2 gears, etc, or that the amount of "blip" required is different going from 6-5 vs. 3 to 2. Second, there are situations, like emergency braking, where the blip is really not needed, but would occur since both clutch and brake a depressed. Third, the "blip" won't activate when downshifting to pickup speed because normally you wouldn't be using the brake in that situation.

As I've discussed above, I believe the way to make an ideal rev matching system is to machine out and install a sensor on the countershaft of the transmission. Remember, the countershaft is in constant mash with the input shaft, so it is a direct reading of the transmission input shaft rotation. Then the system needs to "learn" the correlation between engine rotation and this new sensor. There are x number of teeth on the flywheel, and Y number of teeth on the 5th gear on the counter shaft. Whatever the ratio is between those 2 numbers, the system needs to be programmed for that as the optimization target, because when engaged, the systems's goal is to bring the engine to the exact speed of the input shaft. Remember, whenever the clutch is released, even in neutral, the flywheel and 5th gear on the counter shaft are always spinning at the same relative speed to each other. Then the system needs to monitor the clutch signal. With the clutch pedal released, it allows the throttle pedal signal to reach the DME unaltered. There are actually 2 separate pots in the throttle pedal which the computer uses to confirm that throttle is working properly, both must reach the DME unaltered with the clutch pedal released. With the clutch pedal pressed, the rev matching system then alters the throttle signal in order for the signal from the countershaft sensor and crankshaft position sensor to reach their optimization ratio. This way, no matter now many gears you downshift, the RPM would be matched exactly to what they need to be. This will then also work on the upshift. The system would allow the RPM to drop to a desired lever for the new higher gear, but if you are too slow in making a shift, it will keep the rpm where it needs to be without going all the way to idle, which would happen otherwise. As I mentioned above, I have no electronics expertise to make such a rev matching device, I can only provide my view on how this device needs to function. I can do the mechanical work to my transmission to add the countershaft sensor. If someone here has enough electronics expertise and interest to build such a device, I would be happy to collaborate on this project and use my car as a test mule.
 

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As a couple of folks have pointed out, there is a big difference between "auto blipping" and "rev matching". I think the former is really not very helpful because of the lack of adjustment to cover a myriad of different situations at speed (and that is before we get into having to have your foot on the clutch and brake to activate). I didn't quite get the statement about having your foot on the clutch and brake to UPSHIFT. But even so, auto blipping is when you go to a lower gear at a given road speed simply to take the wear off of the synchros. That is why you have to rev the motor, at a given road speed in a lower gear, the engine will require more rpms. If you are auto blipping on an upshift (save some old Ferrari transmissions that were very balky until warmed up), something is amiss. Revs are dropping on an upshift. No blip required.

As to rev matching, there are some systems out there that allow the DRIVER to turn it on or off. I am perfectly comfortable with that. If I were on a track and trying to get the best lap time, rev matching would make sense.

Wiith the ability to turn the system on or off, the driver remains in control. But to my mind, if you NEED rev matching to get a good downshift for anything short of lap times, then you are better off with something like Porsche's PDK, which is uncannily intuitive at getting/keeping the car in the right gear.

I certainly understand tinkering. If you look at my sig, I am guilty as sin! :) I just don't understand "workarounds" for problems that don't exist. Like lack of auto headlights on my '01. Almost all my other cars have them. I see no need to "improve" my headlights to such an extent that it is now an effort to move my hand a few inches and rotate a knob. One of the reasons the E39 M5 is considered one of the last driver's car (analog) is because of the lack of the car making the decisions.

But as I noted before, each owner is free to make the mods that make them happy!! Not criticizing, just trying to understand from the viewpoint of using an E39 M5 as the platform.

Regards,
Jerry
 
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