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+--- Thread: Using the ALDA as a rev limiter (/showthread.php?tid=4483)
Using the ALDA as a rev limiter - Torkey - 04-06-2013
So.... We've got a great tach with a shift light. I'm in the process of designing a circuit that will trigger an alarm siren when the shift light fires. That got me thinking.... What if I designed a circuit that would send an over boost signal to the ALDA and effectively pull the throttle back.
Sirens are great but are not effective when you have a driver 300% focussed on passing a car they have been chasing for 3 laps.
OM616 what do you think? Have I had too much wine, or is this possible?
RE: Using the ALDA as a rev limiter - raysorenson - 04-07-2013
Use the shift light output to power a vent solenoid that dumps boost to the ALDA. It may require a relay or a transistor if the shift light is an LED.
RE: Using the ALDA as a rev limiter - Torkey - 04-07-2013
(04-07-2013, 08:34 AM)raysorenson Use the shift light output to power a vent solenoid that dumps boost to the ALDA. It may require a relay or a transistor if the shift light is an LED.
My understanding was that boost to the ALDA increases fuel. So I would need to kill the boost to the ALDA when over revving. Currently the ALDA is turned all the way up. To do this mod I would need to turn down the ALDA which might reduce performance at lower boost pressures. Might not be worth it.
RE: Using the ALDA as a rev limiter - raysorenson - 04-07-2013
I like my ALDA, especially since my car has a manual trans and I spend a lot of time at full load in the RPM range where the turbo is unable to make full boost. Adjusting it to make black smoke rather than just a little bit of smoke before full boost came on netted zero decrease in lag. That's just my experience though.
RE: Using the ALDA as a rev limiter - aaa - 04-07-2013
The stop lever interacts with rack as well, you can try attaching something to that.
Why do you need a rev limiter?
RE: Using the ALDA as a rev limiter - willbhere4u - 04-07-2013
There should be a rev governor in the injection pump on my car I can pin the throttle to the floor and the engine wont rev past 5500 rpm
RE: Using the ALDA as a rev limiter - mantahead - 04-07-2013
(04-07-2013, 03:28 PM)willbhere4u There should be a rev governor in the injection pump on my car I can pin the throttle to the floor and the engine wont rev past 5500 rpm
yea, but it would be nice to have full fuel to 5500rpm and cut off at 5500rpm,
if you know what i mean.
even nicer to have 6500rpm
to have full fuel to 6500rpm your going to be reving to over 7000rpm which puts more stress on the engine.
like drifting, if i had a shift light come on and the car started to straighten up, it would be very hard to lift off.
if someone could come up with something here it would be good.
what about some sort of solenoid on the throttle lever like a generator and some fancy linkage or something? solenoid controlled by rpm signal.
RE: Using the ALDA as a rev limiter - raysorenson - 04-07-2013
I've been thinking about this for the past couple of months. The ideal solution is drive by wire.
It would need redundant potentiometers at the pedal (an off the shelf pedal should do fine) and pump or just some nice encoders with redundant stuff built in and failsafe software. Bells and whistles could include speed sensor input for gear dependent fueling and cruise control, egt/cht input for cooling failsafe, MAP input for VNT/wastegate control. Did I leave anything out?
RE: Using the ALDA as a rev limiter - Mark_M - 04-07-2013
(04-07-2013, 02:48 PM)aaa The stop lever interacts with rack as well, you can try attaching something to that.
Why do you need a rev limiter?
sounds like a plan to me. connect a vac operated actuator to the stop lever and plumb the line into the vac line via a solenoid and operate it off your light. It won't act fast like an ignition or fuel cut on a gas car (off on off on rapidly) but it will stop you over revving. You will get all the parts you need of a newer model TD in the scrap yard as they are all vac operated waste gates unless they are VNT.
RE: Using the ALDA as a rev limiter - mantahead - 04-07-2013
what if you already had a wastegate type alda on the stop lever? could this work on the throttle lever. Or tee into the pipe going to alda wastegate and use it?
RE: Using the ALDA as a rev limiter - Mark_M - 04-07-2013
It wouldn't have any way to overcome your foot mashing the throttle. You could still run a solenoid to cut the boost pressure to your alda which by my thinking would shut down the stop lever reducing fuel. What I am not sure about is your setup will never pull the stop lever fully shut so how effective it would be I don't know.
Been thinking about this and all the above might be too slow if you were determined to have max throttle and have this save your engine. None of them would work instantly like a gas car does. There would be slight lag which could mean you would overshoot your rev ceiling especially on some of the really high power engines in the lower gears. Maybe if you set it slightly lower than where you want max to be it could work. Start low and build up to save damage and get a feel for how its going to react. An electric fuel shutoff valve might be better but what where and how I don't know yet.
All that said some of the mad engines out there don't seem to have a problem so maybe all this is just a solution looking for a problem rather than actually being needed.
RE: Using the ALDA as a rev limiter - mantahead - 04-08-2013
I was thinking it would be too slow to react and if it was this easy and worked so well, the pump guys would have come up with something.
I was even thinking along the lines of the way a speed limiter is fitted in older trucks, throttle cable goes into a box then another cable goes to pump, but use rpm rather than speed. But again will probably be too slow.
Any thoughts on any of these ideas, Dieselmeken, PPD?
RE: Using the ALDA as a rev limiter - lgreeley83 - 04-08-2013
Maybe im oversimplifying or something. Couldn't that light when on trigger a relay to have something pinch the line to the alda. Just block boost to alda.
RE: Using the ALDA as a rev limiter - raysorenson - 04-08-2013
The only thing that worries me about using the stop lever is that you could reduce power enough to cause oversteer.
RE: Using the ALDA as a rev limiter - Simpler=Better - 04-08-2013
What about limiting boost? Your EGTs would go up, but your power would go down
RE: Using the ALDA as a rev limiter - Mark_M - 04-08-2013
My concern with cutting the ALDA is that it only reduces fuel not cut it. If you're on full throttle driving it into the limiter I can see it drifting by your limit. Whether this would hurt anything or not I don't know.
Limiting boost might work but again unless you dump all boost it possibly not going to stop the engine immediately.
If you're hitting the rev limiter when you're in a corner enough to cause handling issues your driving is a problem LOL. You shouldn't be on full throttle in a bend and you obviously wouldn't be in the right gear if you're revving out. Unless of course your drifting but then you're supposed to be having oversteer.
RE: Using the ALDA as a rev limiter - willbhere4u - 04-08-2013
If you have an electric signal you could get an electric door lock actuator to move the stop arm on the injection pump
RE: Using the ALDA as a rev limiter - Torkey - 04-08-2013
Great discussion! Lots of perspectives and ideas I hadn't thought of. Cutting all fuel would be easy since I already have a oil kill system set up so if the car looses oil pressure the engine shuts down. I'm looking for something a little more subtle like lifting the throttle.
A couple of people have mentioned there being a delay using the ALDA. How much of a delay are we talking?
RE: Using the ALDA as a rev limiter - Simpler=Better - 04-08-2013
Probably a second or two, it's just a brass bellows in there
RE: Using the ALDA as a rev limiter - raysorenson - 04-08-2013
I would guess it's nearly instant. You could pull the rod on an ALDA and see how fast it snaps back.
RE: Using the ALDA as a rev limiter - willbhere4u - 04-09-2013
The ALDA only limits fuel so it decreases power but it will still rev normally again the engine will not rev past 5500 rpm no mater what you do because of the internal governor
RE: Using the ALDA as a rev limiter - OM616 - 04-10-2013
(04-06-2013, 10:49 PM)Torkey So.... We've got a great tach with a shift light. I'm in the process of designing a circuit that will trigger an alarm siren when the shift light fires. That got me thinking.... What if I designed a circuit that would send an over boost signal to the ALDA and effectively pull the throttle back.
Sirens are great but are not effective when you have a driver 300% focussed on passing a car they have been chasing for 3 laps.
OM616 what do you think? Have I had too much wine, or is this possible?
Do you want this car to be as competitive as possible, or is it a "be a race car driver for a day" car where the drivers do not know how to truly drive a car on a competition course, and you want to protect the engine from a novice?
RE: Using the ALDA as a rev limiter - sassparilla_kid - 04-10-2013
(04-10-2013, 12:27 PM)OM616(04-06-2013, 10:49 PM)Torkey So.... We've got a great tach with a shift light. I'm in the process of designing a circuit that will trigger an alarm siren when the shift light fires. That got me thinking.... What if I designed a circuit that would send an over boost signal to the ALDA and effectively pull the throttle back.
Sirens are great but are not effective when you have a driver 300% focussed on passing a car they have been chasing for 3 laps.
OM616 what do you think? Have I had too much wine, or is this possible?
Do you want this car to be as competitive as possible, or is it a "be a race car driver for a day" car where the drivers do not know how to truly drive a car on a competition course, and you want to protect the engine from a novice?
I'm pretty certain this car gets raced fairly regularly
RE: Using the ALDA as a rev limiter - Torkey - 04-10-2013
The car is raced regularly and some drivers do better than others when it comes to the shift light. Yay for in car video! I don't want to punish the drivers that watch the shift light by pulling the IP back. Probably the best solution is to do a better job picking drivers.
RE: Using the ALDA as a rev limiter - OM616 - 04-10-2013
(04-10-2013, 04:39 PM)Torkey The car is raced regularly and some drivers do better than others when it comes to the shift light. Yay for in car video! I don't want to punish the drivers that watch the shift light by pulling the IP back. Probably the best solution is to do a better job picking drivers.
You must be a mind reader lol