Anyone ever done a boost-by-gear setup on an ALH TDI?

Looking to the future, in order to make our TDI rally car driveable on snow or in other slippery conditions, a boost-by-gear approach to tuning would be most useful. Too much torque and/or to steep a ramp-up in torque just spins tires and hurts performance

Would love to know if anyone has experience with this they could share.

Thanks,

For a manual transmission? There is no gear reporting to the ECU if manual.

Enabled said:

For a manual transmission? There is no gear reporting to the ECU if manual.

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Yes, a manual transmission.

Looking for experience. Maybe someone has used something like a stand-alone electronic boost controller like a Coretex EBC https://sirhclabs.com/

The PDs do have gear reporting (at least I presume that's why people had trouble with 5th gear swaps and cruise control).

Perhaps you could do it based on road speed instead?

-J

Sure, no reason you can not just put together a reference table for Vehicle Speed vs Engine Speed.

What I want to know is what has been done in terms of controlling the VNT using this kind of input to design boost-by-gear tuning approaches?

There is a map in the flash that can limit injection quantity based on speed vs. engine RPM, used for a launch control. The speeds are editable also, and you can create a stepped map if you need.
However it is based on vehicle speed, not gear since there's no gear recognition.

Also it limits fueling, not boost. But a fueling limit is what actually cuts power....

speed vs engine speed would give you information for what gear you are in:
3000rpm and 25mph = 2nd gear
3000rpm and 80mph = 5th gear

The question is whether the table can be made to step up through one gear and then back down at the beginning of the next. Something like:

2000rpm and 18mph = 2nd gear and target boost = 5psi
3000rpm and 25mph = 2nd gear and target boost = 8psi
4000rpm and 32mph = 2nd gear and target boost = 12psi

2000rpm and 40mph = 3rd gear and target boost = 10psi
3000rpm and 52mph = 3rd gear and target boost = 15psi
4000rpm and 60mph = 3rd gear and target boost = 18psi

2000rpm and 60mph = 4th gear and target boost = 18psi
3000rpm and 70mph = 4th gear and target boost = 18psi
4000rpm and 80mph = 4th gear and target boost = 18psi



***I guessed at speed vs RPM but I think it gets the point across

Enabled said:

Also it limits fueling, not boost. But a fueling limit is what actually cuts power....

Click to expand...

Boost and/or fueling. I am most interested in limiting torque in lower gears and in a slower ramp-up in torque at lower RPM in those gears.

My 607whp Honda S2000 had this with the AEM EMS Standalone. It was boost by vehicle speed. You could also do a 3d map using TPS or RPM as other variables.

I just put 275 Hoosier tires on the back instead though

QRS - The biggest thing that I've found to help in low traction conditions is not so much to limit the torque, but to make it more responsive to the pedal. I know this sounds backwards, but hear me out.

With a laggy, slow response, you put your foot into it and just wait for things to happen, once the turbo spools and fuel is delivered, then you're backing out of the throttle as the power is coming on and it's hard to modulate.

With a very quick, fast responding system, you put your foot into it and things happen right away and it's much easier to drive because you don't have the time delay between what your foot does and what the engine does. Most of this is in the tuning I have found. Exact same hardware and 3 different tunes will drive very differently in low traction conditions - the most responsive tune is actually the easiest to drive and modulate wheel spin in low traction conditions.

I've had a 17/22 and am now driving a GTC1444VZ on my ALH - I've had tunes from most of the major tuners on both turbos and the most responsive tune with the 1444 is by far the easiest to drive on snow/ice because the response is more/less immediate. It's like driving a large displacement naturally aspirated engine instead of a small turbo engine.

I've also got a GTB2260 on an otherwise stock BEW (with a tune of course) and while it will spool up at 1800 RPM and make decent power there, the transient response is at least an order of magnitude slower than the ALH and therefore is much harder to drive.

If you're still looking for some sort of electronic traction control system - you might try the motorcycle (sport bike) world. They've got all kinds of relatively simple systems that do this kind of thing and you might be able to integrate it into the QA position feedback signal to the ECU which would trick it into thinking there's more fuel than there is and cut it back without going crazy. This will likely also require some external electronics (op amps and such).

Thanks for all the feedback and information. It sounds like this is a bit more difficult than in a gasser but not impossible it just means making adjustments to the quantity of fuel rather than the target boost..... And of course fooling the ECU successfully.

Torque-by-gear is really the target I am looking to affect.

A snow event is actually a bit easier as you can just run a stock ECU with perhaps some tuning to improve transient response. 90hp and 150lb-ft is plenty on ice with bare tires.

What maps did the ALH models with ESP use, if any?

On BMWs the early traction control systems used a secondary throttle plate to cut power, and then it became integrated into the drive by wire system, which then involves ECU control. Trying to see if anything similar exists for the ALH.

QuantumRallySport said:

The question is whether the table can be made to step up through one gear and then back down at the beginning of the next. Something like:

2000rpm and 18mph (29kph)= 2nd gear and target boost = 5psi
3000rpm and 25mph (40kph)= 2nd gear and target boost = 8psi
4000rpm and 32mph (51kph)= 2nd gear and target boost = 12psi

2000rpm and 40mph (64) = 3rd gear and target boost = 10psi
3000rpm and 52mph (83)= 3rd gear and target boost = 15psi
4000rpm and 60mph (96)= 3rd gear and target boost = 18psi

2000rpm and 60mph (96)= 4th gear and target boost = 18psi
3000rpm and 70mph (112)= 4th gear and target boost = 18psi
4000rpm and 80mph (128)= 4th gear and target boost = 18psi

Click to expand...

You can sort of do this with the launch control map.
Set the LC map with y axis of speeds from 20 to 128 kph.
Perhaps make the lower values closer together, for finer control at lower speeds.

The 29-51 kph speeds, you set the power you want (LC map is in % of power). Try to keep it flatter, you can't jump so quick with this map especially with not too much graduations.

The 64-96 km range can run a higher number... as you are in 2nd gear at that time.

The 96-128 can run a higher number.

The only drawback is that if you are in a higher gear earlier, let's say 3rd at 70 kph, it will be limited by what you set for 2nd. But in racing you don't usually do that.

Or just get the abs pump that has TC... very easy to do on 2001+ cars, just swap the pump and you can run a wire to a switch that can disable it. It's not very intrusive, especially in the higher gears. Since we have drive by wire, the abs/tc unit does a really good job in managing power. It also helps that it is a diesel, where the cut is just fueling, no need like in a gasser to limit the air. So the turbo can usually hold onto some boost while limiting!

Then you can do what some of us have done, a launch control map that allows for a certain % of slip:
http://forums.tdiclub.com/showthread.php?t=446400&page=2


Gear speeds in mph
http://supradave.com/tech/gearspeed/comparator.php?do_what=

Is this using ABS sensors for speed or VSS?

I have no ABS sensors, pump, or ecu

1st gear is totally useless anyway. I always start in 2nd gear.

Would be useful to limit torque to 150lb-ft till 30mph and 200lb-ft until about 40mph

If you want to limit torque based on speed then use the "Launch Control" map in the EDC15. It's goes based on RPM and VSS, so you can limit fuel at lower speeds pretty easily.

Yes you can limit torque per gear on an ALH ecu, I've been doing it for over a year on my personal car and a couple others to prevent wheel spin. The problem is that you can't limit boost except for what you get as a result, you get high exhaust pressure as a result.

LC map is not a % power, its actual mg/str

What kind of side effects would one get from high exhaust pressure?

Thought about trying to use the apexi avcr?

mostly just wear and tear on the turbo, exhaust pressure is much greater than boost pressure.

It also makes it less efficient. Ex: 30 mg/s fuel with 5 psi gives more power than 30 mg/s with 15 psi.

I'm not sure if the launch control map changes the IQ requested though.
If it does, then the boost will be lower, based on what the fueling result is.

If not - Like in my engine temp fuel limiter - then it will try to get the boost based on the pedal IQ request. ( I know the fuel limiter doesn't lower the boost because when testing, I had it set to some low fueling and it was trying to make 20+ psi still- based on 100% pedal which is 80 iq in my tune)

it doesn't change the IQ request, it changes the IQ limit based on RPM. See measuring block 008 once its set below the torque limiter map.

What is it a % of?
Torque limiter?
Smoke map allowed IQ?
Driver Wish?

I haven't played with the LC maps besides limiting rpm based on speed (slip control)

its not a percentage of anything like I said above, its an actual torque limiter. Put 20 in all those cells and you'll get 20mg/str