cruise controll warning

I've seen / heard this before but can't see how it can be correct, surely if the cruise controll senses that your speed has increased it would automaticaly back off, any thoughts from those who have knowledge of the way cruise works?



A 36 year old female had an accident several weeks ago. It was raining, though not excessively when her car suddenly began to hydroplane and literally flew through the air. She was not seriously injured but very stunned at the sudden occurrence! When she explained to the Police Officer what had happened, he told her something that every driver should know -

NEVER DRIVE IN THE RAIN WITH YOUR CRUISE CONTROL ON..

She thought she was being cautious by setting the cruise control and maintaining a safe consistent speed in the rain.... But the Police Officer told her that if the cruise control is on,your car will begin to hydro-plane when the tires lose contact with the road, and your car will accelerate to a higher rate of speed making you take off like an airplane. She told the Officer that was exactly what had occurred. The Officer said this warning should be listed, on the driver's seat sun-visor along with the airbag warning.

NEVER USE THE CRUISE CONTROL WHEN THE ROAD IS WET OR ICY

We tell our teenagers to set the cruise control and drive a safe speed – but we don't tell them to use the cruise control ONLY when the road is dry.

The only person the accident victim found who knew this, (besides the Officer), was a man who'd had a similar accident, totaled his car and sustained severe injuries..

NOTE: Some vehicles (like the Toyota Sienna Limited XLE) will not allow you to set the cruise control when the windshield wipers are on.

Even if you send this to 15 people and only one of them doesn't know about it, it's still worth it. You may have saved a life.

If the speedo sensor is on the transmission which is the norm, the engine will ensure the drive tyres maintain the same speed (and thus tyres continue rotating the same).

Now... if the speedo sensor was say like the old dub, on a front wheel and its a rear wheel drive car, if you were to hydroplane and your front tyres slowed down (as it glides or bull dozers into the water while loosing traction), the cruise control would drive the engine harder, drive the rear wheels harder until that speed sensor reading is where it should be at the front tyre. I can see that getting hairy.

Mind you, i'm yet to see a cruise control setup that goes WOT, so it won't 'take off' but gently accelerate :S.

Gently accelerating sure beats braking while hydroplaning though in so many ways though, assuming no abs. No no to braking, just ride it out.

That's a load of rubbish. Even if you were hydroplaning, all your wheels should still be turning at more or less the same speed as before, so there would be no reason for the cruise control to accelerate. As far as the point where the car "literally flew through the air", unless you were hydroplaning over a hump-backed bridge at double the speed limit, this is not even remotely possible.

Bullshit alert!

I can tell you with 100% authority that if you are driving a 2007 Mitsubishi lancer up Mt Ousley with cruise control on and you hit a stream of water across the road the only thing that happens is that the cruise control drops off leaving you confused as to why your car just suddenly lost power. Expect no taking off like an airplane or an aeroplane.

Yep same with a 2012 Toyota Rav4 if you hit even a pretty small puddle (on Bruce Hwy at Northlakes) it just automatically cancels the cruise making car slow suddenly & makes you wonder WTF is wrong with the car... No take off....

Maybe different in older cars, although My old 1994 Nissan Bluebird SSS which didn't have traction control didn't even do it either....
Pretty sure car that this story was on was an EF Falcon (94-96)?

Don, take it from me that this is all true. How it works?
1. When you hit a big enough puddle on the road it slows the vehicle. Try this yourself if you have not experienced it before. The bigger the puddle the faster you slow.
2. What happens when the car slows, the cruise control tries to increase the speed. The more speed that gets wiped off the more the car accelerates.
3. If the puddle is deep enough, you are aquaplaning.

Example, your doing 100 km/h and you hit a puddle, car slows rapidly, to say 80km/h, the cruise control gives a heap of accelerator to increase speed, but because the tyres are aquaplaning, the wheels are spinning back up to set speed 100km/h.
Now the car is doing 80km/h and the wheels are doing 100km/h and then when you regain traction, it launches the car back up to speed and it will keep accelerating until it reaches 100km/h no matter what the direction the car is travelling, forwards, backwards or sideways, until either the you turn off the cruise control or touch the brakes.

Manufacturers are aware of this and now have set parameters within which the cruise control operates. If a sudden acceleration is out of those parameters, it shuts it down. Or as you mention, turn on the wipers, it cancels the cruise.

Remember, this only happens under certain conditions, and if you have had it happen to you, you will know about it. When it happened to me, it was a real WTF moment, because when the car regains traction, HOLD ON!

Dave
PS Happy New Year!

Hi

My name is Steve and I'm a cruise control addict and this sounds like load of shit, maybe the driver hit the accelerator pedal instead of the brakes, tell me that has never happened before.

I have retro fitted cruise to an old Audi 100, my yellow 1302 and now my 1303.

Steve

ragged wrote:Don, take it from me that this is all true. How it works?
1. When you hit a big enough puddle on the road it slows the vehicle. Try this yourself if you have not experienced it before. The bigger the puddle the faster you slow.
2. What happens when the car slows, the cruise control tries to increase the speed. The more speed that gets wiped off the more the car accelerates.
3. If the puddle is deep enough, you are aquaplaning.

Example, your doing 100 km/h and you hit a puddle, car slows rapidly, to say 80km/h, the cruise control gives a heap of accelerator to increase speed, but because the tyres are aquaplaning, the wheels are spinning back up to set speed 100km/h.
Now the car is doing 80km/h and the wheels are doing 100km/h and then when you regain traction, it launches the car back up to speed and it will keep accelerating until it reaches 100km/h no matter what the direction the car is travelling, forwards, backwards or sideways, until either the you turn off the cruise control or touch the brakes.

Manufacturers are aware of this and now have set parameters within which the cruise control operates. If a sudden acceleration is out of those parameters, it shuts it down. Or as you mention, turn on the wipers, it cancels the cruise.

Remember, this only happens under certain conditions, and if you have had it happen to you, you will know about it. When it happened to me, it was a real WTF moment, because when the car regains traction, HOLD ON!

Dave
PS Happy New Year!

Dave, that is EXACTLY what happened to my son, Tim, in his V8 Maloo ute.

He was traveling at 110 kph up Catherine Hill [near Mittagong] on the freeway, cruise control set. It was pouring rain and dark, and half-way up the hill there was a 'river' of water across the road.

When the ute hit water, it slowed rapidly, and the cruise control quickly got the rear wheels back to the set speed. Fortunately Tim can drive well http://vimeo.com/search?q=tim+mackie+record , as a Maloo sideways at 110 kph needs some attention! No damage done, and lesson learned.

It is NOT a "load of shit" at all.🙅

Name one car that disconnects when the wipers are on.

Yes
I have read about this before...

cruise control on later vehicles does NOT just hold the throttle until its released by braking..

All computer controlled nowadays..

Lee

[/quote]
Dave, that is EXACTLY what happened to my son, Tim, in his V8 Maloo ute.

He was traveling at 110 kph up Catherine Hill [near Mittagong] on the freeway, cruise control set. It was pouring rain and dark, and half-way up the hill there was a 'river' of water across the road.

When the ute hit water, it slowed rapidly, and the cruise control quickly got the rear wheels back to the set speed. Fortunately Tim can drive well http://vimeo.com/search?q=tim+mackie+record , as a Maloo sideways at 110 kph needs some attention! No damage done, and lesson learned.

It is NOT a "load of shit" at all.🙅 [/quote]

Can also say ths is not a load of shit.

Had a Holden V8 ute also. No traction control on this one. Cruise on pouring rain and before i knew what happened i had spun 3 times on the highway at 110 ended up in the middle of the road bogged to sills luckily no damage.
Could have turned out a lot worse. I think it was in the owners manual to turn it off. I hadn't read it as i had only just picked the car up an was on way home.
I never have cruise on in the wet now traction control or not.

AA003 wrote:Name one car that disconnects when the wipers are on.

I have heard Lexus have implemented it with Toyota soon to follow. This is just what I heard from our GM product trainer who went to Detroit last year for a look at all the new technogy to be coming out soon from a hanful of companies. Apparently Holden were going to install this feature on the Malibu because it was going to be aimed as a car for fleet sales and it would help prevent accidents in rental cars. But then they decided too many people would take the car back to the hire company and say the cruise didn't work. A quick Google search would tell you for sure who is using this feature or soon to be.

I recall discussing this with a club member a few years ago with his T5 towing a car on a trailer.
Hit a big puddle on the hay plains heading to Warwick.
As the vehicle slowed dramatically the rear wheels maintained a steady 110 kph.
Scared the absolute Bejeesus out of him!

Despite the configuration of the vehicle ( front or rear wheel drive, front or rear drive speedo), it's the cruise control's job t maintain speed.
If the drive wheels are hydroplaning, they have effectively NO traction.
So they are going to spin.
From here on in, all bets are off.

This is just another example IMHO of the degradation of driving skills in the modern age.
Power steering, cruise control, ABS, reverse assist,proximity sensors, parking assist etc. etc.
The vehicle is doing all the work, the drivers are becoming less skilled, and are less able to deal with a crisis when it happens.

Lucky Phil wrote:I recall discussing this with a club member a few years ago with his T5 towing a car on a trailer.
Hit a big puddle on the hay plains heading to Warwick.
As the vehicle slowed dramatically the rear wheels maintained a steady 110 kph.
Scared the absolute Bejeesus out of him!

Despite the configuration of the vehicle ( front or rear wheel drive, front or rear drive speedo), it's the cruise control's job t maintain speed.
If the drive wheels are hydroplaning, they have effectively NO traction.
So they are going to spin.
From here on in, all bets are off.

This is just another example IMHO of the degradation of driving skills in the modern age.
Power steering, cruise control, ABS, reverse assist,proximity sensors, parking assist etc. etc.
The vehicle is doing all the work, the drivers are becoming less skilled, and are less able to deal with a crisis when it happens.

Did he turn off ASR for this to happen, if not his ABS sensors are faulty and not measuring wheel speed as they are rotating.

Lucky Phil wrote:I recall discussing this with a club member a few years ago with his T5 towing a car on a trailer.
Hit a big puddle on the hay plains heading to Warwick.
As the vehicle slowed dramatically the rear wheels maintained a steady 110 kph.
Scared the absolute Bejeesus out of him!

Despite the configuration of the vehicle ( front or rear wheel drive, front or rear drive speedo), it's the cruise control's job t maintain speed.
If the drive wheels are hydroplaning, they have effectively NO traction.
So they are going to spin.
From here on in, all bets are off.

This is just another example IMHO of the degradation of driving skills in the modern age.
Power steering, cruise control, ABS, reverse assist,proximity sensors, parking assist etc. etc.
The vehicle is doing all the work, the drivers are becoming less skilled, and are less able to deal with a crisis when it happens.

The T5 is front drive......or was it a Synchro?

AA003 wrote:Bullshit alert!

absolutely!

but some food for thought though.

I have bob jane tyres on my holden atm which are the worst tyres anyone can own for wet driving. They will wheel spin at a drop of a hat in the wet. literally off idle they spin.

Anyway, when I engage cruise control in 3rd or 4th in the rain, the initial surge of torque is enough to kick the rear end due to the tyres having no grip in the rain. It can do this on cruise resume as well (accelerating). It not the fault of the cruise control, its the horrific bob janes. It would do this normally when slowly accelerating anyway.

Otherwise there is no issue when cruising as a constant speed is maintained, thats what its suppose to do. Also handy having a manual with cruise control as it engine brakes automatically coming down hill. = no accidental speeding fines🤓

I use cruise control all the time in the wet or dry, the car hydroplanes regularly, the cruise control does not react at all to it. Absolutely 0 effect or relationship to hydroplaning . I would even say its better than me as its very very touchy accelerator.

ragged wrote:Don, take it from me that this is all true. How it works?
1. When you hit a big enough puddle on the road it slows the vehicle. Try this yourself if you have not experienced it before. The bigger the puddle the faster you slow.
2. What happens when the car slows, the cruise control tries to increase the speed. The more speed that gets wiped off the more the car accelerates.
3. If the puddle is deep enough, you are aquaplaning.

Example, your doing 100 km/h and you hit a puddle, car slows rapidly, to say 80km/h, the cruise control gives a heap of accelerator to increase speed, but because the tyres are aquaplaning, the wheels are spinning back up to set speed 100km/h.
Now the car is doing 80km/h and the wheels are doing 100km/h and then when you regain traction, it launches the car back up to speed and it will keep accelerating until it reaches 100km/h no matter what the direction the car is travelling, forwards, backwards or sideways, until either the you turn off the cruise control or touch the brakes.

Manufacturers are aware of this and now have set parameters within which the cruise control operates. If a sudden acceleration is out of those parameters, it shuts it down. Or as you mention, turn on the wipers, it cancels the cruise.

Remember, this only happens under certain conditions, and if you have had it happen to you, you will know about it. When it happened to me, it was a real WTF moment, because when the car regains traction, HOLD ON!

Dave
PS Happy New Year!

I can tell you for sure, when I hit a massive puddle or even when the road surface drop s and rear wheels leave the ground the engine actually slows down.

what seems to happen is yes the car slows down, the engine may or may not momentarily speed up but a soon as the driven wheels loose traction they want to speed up and instantly the cruise control backs off to maintain speed. Because the cruise control backs off instantly (or very quicky) and has a tenancy to very slowly accelerate at first and gradually increasing acceleration over time , that in turn gives it a slowing down bias when rear wheels loose traction.

every time I go over a massive drop in road surface and the rear wheel get air borne i loose speed and feels like a loss of power. There is no classical revving off it tits like you get in games while airborne.

when hitting puddles its hard to say if its just the water slowing you down or the water and engine as well due to traction loss and cruise backing off.

I know a lot of factory cruise control systems have tones of safety features programed in to them. Even in the worst scenarios there is features to counter that. I know my factory setup has them. believe me I tried to fault it o make sure its safe.

How often do you hit a puddle large enough to slow you down while using cruise control?

If it's raining that hard you would be varying your speed anyway.

vlad01, when you find yourself in a hole..STOP DIGGING - it's an old rule.

Driving T5 in the rain, with the race car on the trailer, overtaking semi with not a lot of distance from oncoming traffic the cruise controll just cut off....the loss of speed made the situation pretty hairy...fortunately I did get away..

Hi Greg

Your sons experience comes almost 1st person so it has to be respected.

A Maloo ute would be handful in wet conditions

The ancient Dana cruise control that I've retrofitted to my cars has an engine speed sensor, when you change gear it detects the sudden rise in engine rpm and cuts off as soon as the clutch pedal is depressed, its a shame the cars that have had issues don't have this feature, I'm sure it would help in these extreme conditions, and the people whose cruise has cut out in these conditions, their cars must have this feature.

As for "This is just another example IMHO of the degradation of driving skills in the modern age." I disagree, cruise control if properly used is a great safety feature, if you don't have to constantly check your speed the driver can pay more attention to the road and what's going on around them.

Steve

AA003 wrote:How often do you hit a puddle large enough to slow you down while using cruise control?

If it's raining that hard you would be varying your speed anyway.

well if the government would fix the roads in vic then I could drive not in a lake when it rains lol. Pretty much at least 50 times on the way to work when the road it wet. There is inadequate drainage and the angles of the roads just holds water in the middle.

Yes I do vary. when I see a puddle 50m long as wide as the road. I slow down naturally.

1303Steve wrote:Hi Greg

Your sons experience comes almost 1st person so it has to be respected.

A Maloo ute would be handful in wet conditions

The ancient Dana cruise control that I've retrofitted to my cars has an engine speed sensor, when you change gear it detects the sudden rise in engine rpm and cuts off as soon as the clutch pedal is depressed, its a shame the cars that have had issues don't have this feature, I'm sure it would help in these extreme conditions, and the people whose cruise has cut out in these conditions, their cars must have this feature.

As for "This is just another example IMHO of the degradation of driving skills in the modern age." I disagree, cruise control if properly used is a great safety feature, if you don't have to constantly check your speed the driver can pay more attention to the road and what's going on around them.

Steve

I agree on the last statement especially. I am checking my speed constantly when I dont use it as its so touchy and few times when looking at my speed drifted from my lane or off the road a little. Makes me angry that they police the speed so much.

One of the main reasons i use it on all highways. So I can drive and concentrate and not have a sore foot trying to hold between 1-2% throttle all the time.

I can just see it. Some one will kill some person trying not to speed coz they were looking at their speed.


back to the cruise control. What is the min cruise enable speed on some of you guys cars? Mine does not allow until 60km/h

HappyDaze wrote:vlad01, when you find yourself in a hole..STOP DIGGING - it's an old rule.

not if you intend to push other people into it.

40. Works like a pit lane speed limiter through school zones
😀

mine would be too scary to use at that speed. I shit bricks couple of times coming up to an intersection and accidentally turning on cruise instead of turning it off.

Its like launching the car side stepping the clutch when your actual intentions were to slow down using the brakes. 🤪 its only for a split sec when the cruise comes in, but at lower gears its a mighty big boot in the pants and scares the crap out of you. You never forget where the brake pedal is after that 😂

The Rav's min is just under 40kph... Cruise has come a long way because with it, if you hold down decelerate/coast after 3-4seconds it actually applies the brakes...

Depends on the car I guess.
My Supra TT and also the Soarer TT I had use the front wheel brake ABS sensors to determine speed for the cruise, and the ECU spped signal came from the gearbox, so when you went around a gravel corner and the tyres bit, you lost a few kph, so the power was applied to gain speed. It also happened a few times on a wet freeway when you hit a lot of water running across the road.
Only issue with this is a 300kW twin turbo doesn't stop turning the tyres instantly like a V8 Maloo when you get off the throttle, they keep turning for a half to full second.
A few moments there for me in the past.......

see for me, when the throttle snaps shut, the rear wheels lock a little on slippery surfaces up to 3rd/4th. 2nd locks on dry road a fair bit, 1st well that fully stops the wheels from turning at all and is just like locking the hand brake. I can actually spin the wheels and then fully lock them in one throttle application in 1st at low speed without using anything but my throttle.

lucky that cruise does not work below 60k so that is not a problem. But a major advantage as I can't overrun with cruise on.

Vlad you need to piss those tyres off real quick - they sound downright dangerous.

yeah I reckon. shithouse.

Let me give everyone a heads up on bob janes.

I wish i had found these reviews earlier. Go though a couple of pages. Terrifying

http://www.productreview.com.au/p/bob-jane-all-rounder.html

I also had similar problems with kelly tyres years ago when i first started driving. They got the silent drift of death in DRY! conditions, wet was as bad as job janes. The tread never wore out, they were hard as rock. I lost it many times without warning. Scary as!

I reckon bridge stones have been the best for me. They can be pushed really hard and still grip and are predictable in their behavior.

omg! just read the reviews on the xenon tyres. Thats what my new mags on the other car has on them.
The reviews are even worse for wet conditions.

This is going to be one expensive operation to replace all these 🙅. Anyone got a recommendation? Thinking of trying Potenza RE002. Reviews dont seem to fault them.

Lucky Phil wrote:I recall discussing this with a club member a few years ago with his T5 towing a car on a trailer.
Hit a big puddle on the hay plains heading to Warwick.
As the vehicle slowed dramatically the rear wheels maintained a steady 110 kph.
Scared the absolute Bejeesus out of him!

Despite the configuration of the vehicle ( front or rear wheel drive, front or rear drive speedo), it's the cruise control's job t maintain speed.
If the drive wheels are hydroplaning, they have effectively NO traction.
So they are going to spin.
From here on in, all bets are off.

This is just another example IMHO of the degradation of driving skills in the modern age.
Power steering, cruise control, ABS, reverse assist,proximity sensors, parking assist etc. etc.
The vehicle is doing all the work, the drivers are becoming less skilled, and are less able to deal with a crisis when it happens.

I can only see this happening in a T5, is if the cruise control was a cheap aftermarket unit.
The factory cruise control on a T5 will disconnect when you hit big puddle.

So I think the warning that the OP talked about, is possible on an aftermarket unit. I can't see it happening on a factory fit cruise control on any car.

I wonder if this would happen on the first series of Amaroks, as most of the cruise controls on those were aftermarket units fitted here in Australia.

Haha, dad's VP commodore has Bob Jane all rounders. the rubber is so hard the tyres last forever!

Hooks up the commodore like stupid just by taking a corner a little quicker than typical. Really makes a boat out of em with the rocky sideways action 😂

Caught me out bigtime once as a kid driving dad's car back home and accelerating out of a corner. bastard auto dropped a gear and rear end hooked out, eep!

I pull off a few aftermarket units on somes cars. None worked so I think they would be unsafe.

some of the kits are so dodgy that they glue a magnet to a tail or drive shaft and use a read switch as the pickup🤪

sounds reliable.

bajachris88 wrote:Haha, dad's VP commodore has Bob Jane all rounders. the rubber is so hard the tyres last forever!

Hooks up the commodore like stupid just by taking a corner a little quicker than typical. Really makes a boat out of em with the rocky sideways action 😂

Caught me out bigtime once as a kid driving dad's car back home and accelerating out of a corner. bastard auto dropped a gear and rear end hooked out, eep!

yep, That is exactly what i drive for my get around automobile and the same tyres. Except I have to deal with manual and extra bottom end torque as the extractors have runners much much longer than stock( aprox 3-4 x longer), torque is moved heaps down range.

If anyone has driven a VN series 1 with LN3 engine will know what I mean. Its similar to that.

Interesting you say your dad'd tyres were hard. My job janes are softest tyres I have so far had. I can't understand why they don't grip. Its like they leach oil and self lubricate in the wet?

vlad01 wrote:I pull off a few aftermarket units on somes cars. None worked so I think they would be unsafe.

some of the kits are so dodgy that they glue a magnet to a tail or drive shaft and use a read switch as the pickup🤪

sounds reliable.

The cruise control kit on my Audi & 1302 did this but I used cables ties instead, never had a problem, my new one uses the VSS

Is your kit servo driven or vacuum operated?


All the aftermarket ones I seen were vacuum actuated and did not work. All my factory holden ones are a self containing servo actuated units. Never had one fault or ever heard of it either. These units are over 20 years at the youngest now and work beautifully.

Come to think of it, you could retro fit these units to other cars as they work standalone. All they need is VSS signal, power and switch inputs.

does anyone want to see one of these units? I can get a pic when I'm home.

I have had two vac operated ones that have worked for years, on the beetle i put the magnet and pickup in the front disc brakes i made, on the mitsubishi the pickup went on the tail shaft, both are still going after all these years, depends on who fits them as they are quite hard to get to work reliably.

My brother had ( still has, but sits in the paddock now) an EB falcoon.

Its has factory cruise and its vacuum operated. The car doesn't generate enough vacuum for anything to work properly, the cruise does not work. Heater doesn't even turn on anymore as there isn't enough vac to open the tap.

also my Niece's ford ute looses all vacuum for all vac operated items in the car when going up hill. I would imagine if that had factory cruise it would shit bricks trying to go up hill.

ford never fitted a vac reservoir nor a check valve to any of the cars throughout the 90s is seems. I can't see the logic in their cruise control if the vac doesn't even work properly. I wonder why they didn't just fit a servo type to those cars?

I fitted a vacuum reservoir on the beetle and the mitsubishi is a diesel with a vacuum pump, in the instructions it states you may need to fit a vacuum reservoir. the beetle is a 2054 with twin 44 IDF's , works well.

At least you got that right. 😁

Anyone had cruise control jam up? My friend had it happen in his AU wagon. He said when he came up to an intersection it did not want to stop and had to use both feet on the brake and still was trying to speed up.

He killed the key to stop it. When he restarted the car in park it just red lined straight away. I recall he said he unhooked the cruise control cable, fiddled with the cruise cable and got it unstuck and it was alright after that?

I think that would be way more scary than going through a few puddles.

Hi

The cruise control for my 1303 is made by Rostra and is servo driven, the one I had on my Audi and 1302 was also servo driven. I'm not sure how vacuum unit would deal with boost.

Good to hear I'm not the only VW driver who appreciates cruise control on old VWs, driving a light car with a bit of extra power is just asking to get a speeding fine.

With magnets mounted on the CV joints you would feel a small serge going around corners as the outside wheel sped up to keep up with the inside wheel.

Fitting these units needs some care, they come with a small chain link to allow the cruise control cable to go slack when not in use otherwise the cable could get damaged if its forced back into the unit.

Steve

1303Steve wrote:I'm not sure how vacuum unit would deal with boost.

Volkswagen use a vacuum pump. When you hit the brake or clutch, it switches the pump off and vents the line. Very safe.

That's OEM, I'm not sure how an after market unit would deal with say putting 20 psi through it, I would imagine that the diaprham would be getting pushed both ways which might lead to preamture failure and if its using vacuum to move throttle lever, the vacuum would disappear when a turbo motor comes on boost so would that work

vac res and check valve.

i have enough vac without the engine for few days of climate control gear to keep operating.

the one way check valve is key. it doesn't allow pressure in, only suction out.

1303Steve wrote:That's OEM, I'm not sure how an after market unit would deal with say putting 20 psi through it, I would imagine that the diaprham would be getting pushed both ways which might lead to preamture failure and if its using vacuum to move throttle lever, the vacuum would disappear when a turbo motor comes on boost so would that work

That's a safety feature to stop losing control when you hit a puddle.😂

Donn has posted a warning about cruise control, and it is worth taking notice of. 👍 What is needed is a bit of 'common sense'......even if it's net all that common.

If you let someone else take control of your car's accelerator pedal [via cruise control], then be aware of their limitations. Be ready to re-take control at a moment's notice. Most of the time cruise control will work fine, but be aware that it IS POSSIBLE for things to go wrong.

As a kit it takes a lot care to install without problems, they are not for the back yard mechanic even though they are sold that way, the ones i have took hours to install and get the linkage working correctly, i could easily see them jamming with the throttle open if fitted without care.

HappyDaze wrote:Donn has posted a warning about cruise control, and it is worth taking notice of. 👍 What is needed is a bit of 'common sense'......even if it's net all that common.

If you let someone else take control of your car's accelerator pedal [via cruise control], then be aware of their limitations. Be ready to re-take control at a moment's notice. Most of the time cruise control will work fine, but be aware that it IS POSSIBLE for things to go wrong.

I agree, there is a time and location for using cruise control, but if your not constantly looking at your speedo for fear of being booked for speeding you have a better chance of seeing something about to go wrong if your using cruise control, that is as long as the brain isn't in cruise control as well.

HappyDaze wrote:Donn has posted a warning about cruise control, and it is worth taking notice of. 👍 What is needed is a bit of 'common sense'......even if it's net all that common.

If you let someone else take control of your car's accelerator pedal [via cruise control], then be aware of their limitations. Be ready to re-take control at a moment's notice. Most of the time cruise control will work fine, but be aware that it IS POSSIBLE for things to go wrong.

Thanks HappyDaze, though that's not quite what my message was intended as but more as a question about the warning, I am still not sure that it is a valid warning, if the car starts to aquaplane then that means the tyres have lost traction and they would begin to rotate faster, in my mind that means that the CC would sense that the car is travelling faster than the set speed (not because it is travelling faster but because the wheels rotating faster would send a signal to the CC that it aws 🤪) surely that would mean that the CC would back off, not "suddenly launch the car into the air".
I guess it's just another of those things that my miniscule brain can't comprehend.
THanks
Don

you are spot on Don.

What you think happens is what actually does happen.


When you have the driven wheels slip and speed up and of course the car wont speed up because of inertia. The cruise backs off and you feel it sort of loose power for a sec.

It happens to my car all the time. I occasionally feel a sudden but gentle loss of speed then followed by gradual acceleration back to the set speed.

I get that effect going over road surface level drops as the heavy ass live axle (somewhere around 80kg+ unsprung weight) can't fall to the lower surface quick enough and wheel leave the ground momentarily.


what is possible though is if your cc unit reads the non driven wheels and the car is slowed down enough by what ever means, the cc will try to accelerate the driven wheels. If traction is low enough and cc is really trying then you could get a situation where you get run away wheel spin. And if you started to spin out and in this example I will say the sensor is in the front wheels and the rear drive, yep the front wheels would really slow down in a loss of control situation and the cc would go mental trying to speed back up ( if you decided not to disable by using the brakes) . That would make it even worse as the rear wheels spin more and more

the unit should never be setup like this, its just asking for it. My guess is no factory unit would be like that ?

One way to see how the unit reacts to a loss of speed beyond its own control is put the car in neutral after its rolls down a hill. Nothing at first as you are rolling faster than the set speed, then soon enough when the car slows down it will go flat stick and redline trying to speed up. Some of the smarter units don't do this, but so far all cars I have tried this in rev off there heads.


funny this thread. I remember I submitted this exact myth to the mythbusters for testing some 5 years ago. I don't think it got popular enough to test though.

Don, Here it is again…

1. When you hit a big enough puddle on the road it slows the vehicle. Try this yourself if you have not experienced it before. The bigger the puddle the faster you slow.
2. What happens when the car slows, the cruise control tries to increase the speed. The more speed that gets wiped off the more the car accelerates.
3. If the puddle is deep enough, you are aquaplaning.

Example, your doing 100 km/h and you hit a puddle, car slows rapidly, to say 80km/h, the cruise control gives a heap of accelerator to increase speed, but because the tyres are aquaplaning, the wheels are spinning back up to set speed 100km/h.
Now the car is doing 80km/h and the wheels are doing 100km/h and then when you regain traction, it launches the car back up to speed and it will keep accelerating until it reaches 100km/h no matter what the direction the car is travelling, forwards, backwards or sideways, until either the you turn off the cruise control or touch the brakes.

Manufacturers are aware of this and now have set parameters within which the cruise control operates. If a sudden acceleration is out of those parameters, it shuts it down. Or as you mention, turn on the wipers, it cancels the cruise.

Remember, this only happens under certain conditions, and if you have had it happen to you, you will know about it. When it happened to me, it was a real WTF moment, because when the car regains traction, HOLD ON!

Dave

ragged wrote:Don, Here it is again…

1. When you hit a big enough puddle on the road it slows the vehicle. Try this yourself if you have not experienced it before. The bigger the puddle the faster you slow.
2. What happens when the car slows, the cruise control tries to increase the speed. The more speed that gets wiped off the more the car accelerates.
3. If the puddle is deep enough, you are aquaplaning.

Example, your doing 100 km/h and you hit a puddle, car slows rapidly, to say 80km/h, the cruise control gives a heap of accelerator to increase speed, but because the tyres are aquaplaning, the wheels are spinning back up to set speed 100km/h.
Now the car is doing 80km/h and the wheels are doing 100km/h and then when you regain traction, it launches the car back up to speed and it will keep accelerating until it reaches 100km/h no matter what the direction the car is travelling, forwards, backwards or sideways, until either the you turn off the cruise control or touch the brakes.

Manufacturers are aware of this and now have set parameters within which the cruise control operates. If a sudden acceleration is out of those parameters, it shuts it down. Or as you mention, turn on the wipers, it cancels the cruise.

Remember, this only happens under certain conditions, and if you have had it happen to you, you will know about it. When it happened to me, it was a real WTF moment, because when the car regains traction, HOLD ON!



Dave

no not really. Like being airborne and redlining in the air doesn't give you a boost of speed when you land just because your wheels are spinning way faster in the air.

try doing a burnout when you are going 100 already, similar problem not a happens. it may kick the wheels a bit but wont launch the car.

Unless you have 700hp of course. different story.😂

And the other important point is as far my experience goes, all factory fitted cruise units start acceleration real slow and gradually increase over time if the demand continues for long enough. usually 5 sec or longer.

All this theory is making me want and try this out. Might go try this on my driveway latter in the week. set cruise and rip the hand brake to simulate slowing down by a puddle. My tyres suck on gravel so I will find out one way or another.

oh something i forgot about, automatics? do they kickback with cruise control when acceleration is required?

vlad01 wrote:oh something i forgot about, automatics? do they kickback with cruise control when acceleration is required?

Both my Caddy and Forester do, Forester is a real bitch as it shunts down and up through the gears if on a long steep gradiant, there is one such hill on the F3 that I have now come to grips with, I swith the CC off as soon as I start to climb, the Caddy is much better but being a diesel that is probably because of the greater low down torque.

The point you are missing is when you hit a big enough puddle, IT SLOWS YOU DOWN. I am not talking about wet patches.
When you are doing 100 km/h it can be dangerous. Just like any other accident it is a combination of factors. The speed, the road surface, the weather, the depth of the puddle, the amount of tread on the tyres, the experience of the driver just to name a few. Need I mention alcohol or attitude, 'it would never happen to me'.
I have first hand experience of this happening. In the right circumstances, it can be fatal.

vlad what ever you try to simulate this, pulling of a handbrake at 100km/h is foolish! (unless you are a very good driver)

Dave

HappyDaze wrote:

ragged wrote:Don, take it from me that this is all true. How it works?
1. When you hit a big enough puddle on the road it slows the vehicle. Try this yourself if you have not experienced it before. The bigger the puddle the faster you slow.
2. What happens when the car slows, the cruise control tries to increase the speed. The more speed that gets wiped off the more the car accelerates.
3. If the puddle is deep enough, you are aquaplaning.

Example, your doing 100 km/h and you hit a puddle, car slows rapidly, to say 80km/h, the cruise control gives a heap of accelerator to increase speed, but because the tyres are aquaplaning, the wheels are spinning back up to set speed 100km/h.
Now the car is doing 80km/h and the wheels are doing 100km/h and then when you regain traction, it launches the car back up to speed and it will keep accelerating until it reaches 100km/h no matter what the direction the car is travelling, forwards, backwards or sideways, until either the you turn off the cruise control or touch the brakes.

Manufacturers are aware of this and now have set parameters within which the cruise control operates. If a sudden acceleration is out of those parameters, it shuts it down. Or as you mention, turn on the wipers, it cancels the cruise.

Remember, this only happens under certain conditions, and if you have had it happen to you, you will know about it. When it happened to me, it was a real WTF moment, because when the car regains traction, HOLD ON!

Dave
PS Happy New Year!

Dave, that is EXACTLY what happened to my son, Tim, in his V8 Maloo ute.

He was traveling at 110 kph up Catherine Hill [near Mittagong] on the freeway, cruise control set. It was pouring rain and dark, and half-way up the hill there was a 'river' of water across the road.

When the ute hit water, it slowed rapidly, but the cruise control quickly got the rear wheels back to the set speed, even though the ute had slowed to around 100. Fortunately Tim can drive well http://vimeo.com/search?q=tim+mackie+record , as a Maloo sideways at 100 kph needs some attention! No damage done, and lesson learned.

It is NOT a "load of shit" at all.🙅

vlad, just in case you missed this. It ACTUALLY HAPPENED. If you choose not to believe me, that's OK.

Yep, it's easy to say "it's a load of sh!t".
Totally different story when the sh!t is in your pants!