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So I got a crazy idea about a week ago after driving a friends car that had revmatching. I decided to try implementing this in my 07 manual V8 vantage and saw the other thread about sprint boost so thought I'd start a new thread about this project of mine, might be interesting to someone.
Scanned the workshop manual for information as well as logging data with my scanner before deciding what I needed and ordered components.
My mission:
1. True revmatching on downshifts, not just a random throttle blip. I want the revs to match selected gear and stay in sync even as the car slows down for a while.
2. True revmatching/revholding on upshifts. Not as critical as downshifts but would be nice and easy to implement in the process.
3. Throttle input as the car begins to move in 1st or reverse gear. We have a Volvo V60 at work that automatically increses engine speed a bit from standstill to clutch fully released and it is a nice feature. Considering how many times I've stalled the engine during reverse it would be nice.
4. Pedal map modification, be able to modify pedal output to give some more umph at beginning of pedal travel. I'm not sure I will use this function yet.
So, to be able to accomplish above goals there are some sensors that needed to be piggybacked or added to the car. First is current gear input. The manual vantages do not have any idea what gear is selected except reverse, but that is of little help. I got myself two hall effect sensors for this and added magnets to the shifter cables at the stick. The sensors gives an analog voltage depending on magnetic field and I was able to sense the cable extensions with this arrangement. I get bulletproof readings of stick position, ergo selected gear.
Input shaft speed is another one that do not exist, unfortunatley. But there is a work around to this as I now have selected gear data. I should now be able to use vehicle speed to determine input shaft speed with the gear ratio of the selected gear. This should be available via CAN bus and will be calibrated by just driving, as engine speed is input shaft speed when clutch is engaged. Software becomes a bit more complicated though.
Clutch pedal fully released/depressed switches already exists in the car so I can simply piggyback into those. They are 12V so needed to bring the voltage down to 5V first, used a voltage divider 10k and 4.7k for this.
Accelerator pedal sensors is a bit more complicated. The car uses three APP's, not two as is otherwise common. APP1 is a voltage ranging from 4.0V at 0% to 0.5V at 100% pedal input. APP2 is same but reversed, ie. 0.5V to 4.0V. APP3 is not as easy. It seem to be ranging from 0.44V to 3.2V, about 10-20% lower than APP2. I will just interpolate my APP3 value from the two recorded points though so should not be a problem. To be able to output the analog voltage I use 3 - 12 bit DAC chips with a syncronize function.
As I will use CAN data for engine speed, vehicle speed and maby engine temperature (don't want to revmatch higher rpm with cold engine) I will need to try to translate the data on the bus. A backup solution is to use OBD2 protocol but as it creates overhead and is slow I would rather use the data that is already on the bus, all I need to do then is litsen.
I suspect this will be a challenge.
Today I hooked everything up in the car and calibrated what I could, so far so good. Tomorrow it's time to sniff the CAN network and load a basic pedal repeater software and go for a spin. I've written the code for the main software but would rather try a simple pedal in -> pedal out first.
I'll post some pictures when I get back to the garage tomorrow if anyone's curious!
A quick update:
I had some problems yesterday and had no time to begin working on the CAN module. Had a lot of noise on my analog output and moved my ground to solve it. But I managed to get two things working!
1. Throttle input when starting from standstill. It works by simply looking if gear is R or 1st and if so add throttle if clutch is partly released. If clutch is completely depressed or released it does not modify the throttle.
Also, pedal input overrides this function if pedal input is higher than this function generates.
I noticed one thing here though, this function is now set to give 20% throttle in 1st and 25% in reverse, which is a lot!
Still, it's barely enough if going uphill and I will probably have to increase this even more. This engine is really lazy at low rpm's!
2.Pedal mapping. While I was standing on the side of the road with the laptop in hand to increase above value, I also implemented a really simple pedal input remapping function while I was at it. I simply increased pedal feedback to 200% (which also means last 50% of pedal travel is useless) and oh boy..
It's a totally different car to drive!
While moving it is no issue at all. It's not jumpy or hard to maintain a steady speed, but it really feels alive now like a sports car should. Doing manual revmatching is way easier too. I noted she generates a lot more pops and crackles than before, can hear atleast something every downshift. One thing though, rpm's under 1500-2000 still generates slow response, probably due to stock flywheel and tune. So it's not a "magic wand" that made everything better but sure as hell is more fun to drive now!
I'll have to implement the CAN bus functions to retrieve engine and road speed before I can tackle revmatching. Will try to find the time for this in the coming days.
Time..
EDIT: Or if you're wondering the "why" of this project?
Just because it's fun and I really like to have revmatching.
My car (maby all of the v8 vantages) is really slow and heavy to change gears and I also dont like the response of the engine. Yes, I can spend a lot of dollars for a tune, dual plate clutch, light flywheel etc. but what's the fun in that?
I have a new 6 puck springed clutch waiting on install, and will also modify or make a new custom flywheel while at it.
As she is not a daily driver I can do some experiments on her.
So, managed to get the CAN readings to work.
As of now I'm using OBD2 protocol instead of pulling right off the CAN bus. I'll do some test to see how often I can pull the data I need from that protocol, if it's not good enough I can fall back on trying to decode the manufacturers CAN pid's and calculations.
I recon about 4 readings /sec should be enough, but some trials will see if I'm right.
My setup. PC with Picoscope oscilloscope to look at analog voltages and actual CAN data. The MCU with a prototyping board strapped under it for DAC's and CAN module. It sure as hell is not pretty but I can lift it up out of the way for the pedals when doing road trials. Used hot glue to make sure every connection stays in place on the board.
Next step is to do some trials with the OBD2/CAN data, as well as some mapping of engine speed versus road speed for different gears. Depending on air in tyres and tyre sizes this relationship will change so I'd like to have a function in the software that automatically calibrates these values as the car travels in different gears. Will have to do some tests to see how/if big effect turning has on road speed readout too, as different wheels travels at different speeds during a turn.
On the other hand, might not be a problem at all and I'm just blowing up this issue. More updates to follow...
EDIT: Another quick update, takes about 10 ms to read engine rpm with OBD2. That's way better than I thought and will suffice.
Last edited by Anders S; Jun 19, 2023 at 03:50 PM.
I purchased the Auto-Blip Downshift module for my 06 Vantage for rev match, however, I can't find anybody that has the know how to install it. The company is aware of one UK racing team that uses it for their Aston Martins, so they say it works, however, they don't have any instructions except for the generic ones so I'm kinda stuck.......I'll be curious how your project turns out.
And to those that say, "Just learn to heel/toe!" Yes, I get it, however, I love the auto rev match I've had on my other cars so that's what I like......the lazy mans way........
Do you have any wiring diagrams of the module? I mean what inputs it expect to see and what outputs it produces for the blip? If you can send some information I might be able to help you with wire locations/descriptions and color coding.
The APP sensor wiring is a b*tch to get to, at least APP1 and APP2. APP3 is more forgiving but not much. Make sure that the module can output 3 different analog values for all 3 APP sensors. I have no idea how the ECU interprets the 3 sensors but I'm quite sure that it needs all 3 to not go into forced idle mode with a check engine light.
The clutch switch is quite easy. It has constant 12V on one side which it will pull to ground when clutch pedal is depressed. There are two clutch switches on the pedal assembly, by actuating the pedal you can see which is which. The other sensor is a clutch released switch and works the same way but is normally closed (ie. pulled to ground when clutch is not actuated).
I have no idea about the brake signal, as I'm not using it for anything and didn't bother to hook it up. I suspect that the best way is to hook into the brake lights voltage.
"And to those that say, "Just learn to heel/toe!" Yes, I get it, however, I love the auto rev match I've had on my other cars so that's what I like......the lazy mans way........"
-Yes, the vantage really leaves much on the table when it comes to fun driving. Heel & toe is near impossible with the sluggish response and bad pedal relationship between brake and throttle. It's doable but simply not fun, and that's what this car should be all about.
I'm so disappointed with this car's drive train design over all. I really have no single good word to say about the engineers that designed it, seem to have taken the wrong turn at every single crossroad.
I could go on about this for some time but I like to think that this leaves room for some home engineering improvements, which I like!
Do you have any wiring diagrams of the module? I mean what inputs it expect to see and what outputs it produces for the blip? If you can send some information I might be able to help you with wire locations/descriptions and color coding.
The APP sensor wiring is a b*tch to get to, at least APP1 and APP2. APP3 is more forgiving but not much. Make sure that the module can output 3 different analog values for all 3 APP sensors. I have no idea how the ECU interprets the 3 sensors but I'm quite sure that it needs all 3 to not go into forced idle mode with a check engine light.
The clutch switch is quite easy. It has constant 12V on one side which it will pull to ground when clutch pedal is depressed. There are two clutch switches on the pedal assembly, by actuating the pedal you can see which is which. The other sensor is a clutch released switch and works the same way but is normally closed (ie. pulled to ground when clutch is not actuated).
I have no idea about the brake signal, as I'm not using it for anything and didn't bother to hook it up. I suspect that the best way is to hook into the brake lights voltage.
"And to those that say, "Just learn to heel/toe!" Yes, I get it, however, I love the auto rev match I've had on my other cars so that's what I like......the lazy mans way........"
-Yes, the vantage really leaves much on the table when it comes to fun driving. Heel & toe is near impossible with the sluggish response and bad pedal relationship between brake and throttle. It's doable but simply not fun, and that's what this car should be all about.
I'm so disappointed with this car's drive train design over all. I really have no single good word to say about the engineers that designed it, seem to have taken the wrong turn at every single crossroad.
I could go on about this for some time but I like to think that this leaves room for some home engineering improvements, which I like!
Well, looks like I'm out of luck. The first thing it says on the instructions is that it won't work on cars with 3 APP sensors........so there you go..........
And to those that say, "Just learn to heel/toe!" Yes, I get it, however, I love the auto rev match I've had on my other cars so that's what I like......the lazy mans way........
Agreed. With the paddles, I like when the car does the rev matching. Never thought I'd say this years ago, but I prefer it to manuals. I don't mind (habit) rev matching myself in a manual.
Agreed. With the paddles, I like when the car does the rev matching. Never thought I'd say this years ago, but I prefer it to manuals. I don't mind (habit) rev matching myself in a manual.
I agree... I've had my share of manuals... for a track only car I may like a manual but for spirited street driving, ASM on my Aston and DCT for my BMW are great driving experience.
High performance very flexible buggy whips were very good until they weren't...
I drove dirt track stock cars, formula ford's and other classes in the 1970s and 1980s... all rough cars... there is a reason why manuals are getting phased out. next gen BMW ///M cars won't be available with manuals...
Do you have any of the CAN channel IDs and formulas? I see AiM lists a handful of them for the vantage (like rpm, temperatures, wheel speeds, etc.) but they dont give you the channels of course
