Cruise control options for the 451. Tested and reviewed

[SmartieParts]

Hello folks.

There have been rumors, innuendo, falsehoods, truths, speculations, stories, tales and guesses relating to cruise control options for the 451.

I believe I am the only person on Earth at this moment to have installed, tested, reviewed and compared the two front runners.

In this corner, wearing the plain brown box and bubble wrap, we have the defending champion, weighing in at 387 grams, coming all the way from Düsseldorf Germany, M D C !

And in this corner, wearing the black box with red and white trim, we have the challenger, weighing in at a 299 grams, representing the United States of America.... AAAarea 451 Parts!

So now that I've put this in the proper tone and you recognize this really is the event of the century... let's get to comparing the two!

I've written elsewhere about the cosmetic differences, the installation method differences, the packaging and "professionalism" differences, etc. But when it comes down to it... its how it drives, right? I thought both would be identical and the fight would be on the other stuff. Boy was I wrong!

Let's get a bit technical. Most motor control systems work on a similar principle... its something called a PID loop. P, I and D are variables in a complex mathematical equation that act together to determine output that will achieve a particular goal. In the case of a cruise control, the goal is smooth and steady accelerator pedal control to maintain a speed. That math makes it possible for a "dumb" computer to simulate your foot without the benefits of things like eyes to see the road ahead, etc. Its a stimulus/response thing really... the speed drops, the cruise responds by pressing the pedal harder. The speed goes up, it lifts off the pedal a bit. But exactly how it does that is rather complicated.

The "I" of the PID loop does a lot of the magic, but is also susceptible to causing problems. Especially with "overshoot"

OVERSHOOT - a lesson and comparison

Owners of the MDC on the 450 may have noticed that if you're going up a big long hill say at 100kph, when you finally get over that hill it will accelerate up to say 120kph and you're left saying, "whoa Nelly! WTF!?" and if you're like me you respond by shutting the cruise off before it gets you a ticket. It happens rarely, but most people with one will know what I'm saying. This is caused by the "I" part of the equation and its called "overshoot". What happens is your car is too weak to maintain the speed exactly so you're going 99 or 98 for a long period of time while its set at 100. Of course, this is the "fault" of your car, not the cruise but this "error" builds and builds over time. When you finally crest the hill (remove the car's inability) the "virtual" gas pedal is planted to the floor and it takes quite some time for it to "catch up". Of course, a human will just recognize continued power is no longer needed and lift the foot off the gas but the computer isn't capable of that kind of reasoning. Actually, all cruise controls suffer from overshoot in theory. There's no way around it. But most cars don't have trouble getting up the hill in the first place so you may never notice it. Incidentally, if you leave it alone it will eventually settle out and you'll be back to 100 but it can take awhile.

So while that can't really be helped, it can be "tuned". Would the Area 451 unit be better? Worse? the same? I didn't even have a guess but I was certain the MDC for the 451 would be the same or better than the MDC for the 450.

Nope.

The overshoot on the 450 would only really happen at higher speeds like 100+ and only on long steep hills. For the 451, it happens a lot more frequently, at lower speeds, and at less severe hills. Is this a difference in the cruise? or is it a difference in the car? I don't know. I suspect perhaps they used the same formula for the 450 as they do now for the 451 and its not quite working.

So how bad is it? Its really not that bad, but it depends how sensitive you are and what you expect out of it. On a flat road, if you set it to 80 it Will hold 80 all day without a blink of an eye. You'll never see 79 and you'll never see 81. But go up a hill and it might drop to 70 and once you crest the hill it might go to 85. That variance is more pronounced at higher speeds than at lower ones, with some exceptions due to transmission shifting (see later).

Is the Area 451 Parts version any better? Yes, without a doubt it is. it handles smaller hills and lower speeds with near zero variance. So again, going 80 on a flat road you'll see no variance. Hit a hill and you might drop to around 77 or 78 but you'll not see any overshoot on the way back up. It does very well. At higher speeds again there is some, but its less than that of the MDC. The worst I saw was on this run: Going on "The Connector" (for those familiar with the Kelowna area) with it set to 110, the car started to drop speed on a steep hill and fell to about 100 before the transmission shifted gears to begin accelerating again. By the time the hill was crested, the cruise continued to accelerate briefly up to 114 and then the car shifted back to 5th and the speed quickly dropped to 110 where it was maintained. So not bad, but it was there.

SMOOTH - how was it for you?

Ok, overshoot happens because the car can't keep up and the cruise doesn't know how to react. But what about when you are in speeds and terrain that the car is capable of keeping up? How smooth is smooth? Both units are very good in this regard. The results were interesting. With PID theory, it should be smoother as speeds go up, at least to the point that the car can't continue. However, what I observed was that the MDC unit was considerably smoother at 25 - 30kph tests than the Area 451 version but that reversed by 50kph and the Area 451 version was better at locking on a specific speed on all (reasonable) terrains in the 50 to 90kph range. Beyond 90 you get back into the car's ability to maintain speed so its not really fair comparing the two if hills are involved, but for flatter areas both performed very well at higher speeds. By "smooth" I mean you don't feel a surging as the car is pulsing the pedal trying to maintain speed. It is actually not possible in a PID loop system for the pedal to remain "steady" but the idea is to make the ups and downs so small that you don't feel them and it appears steady.

SHIFT ENGAGEMENTS - what is the effect on the transmission

Some of you might be learning something here... others may know all this already. But I'm going to spell it out. An "automatic" transmission is not nearly as simple - or as smart - as people tend to think. Sure, it shifts for you... but you tell it when, even if you aren't aware of it. How you do that it through the gas pedal. How far you press it, how fast you press it, and how quickly (rate of change) you press it will all provide cues to the transmission to the gear you wish to be in. For example, you're going up a steep hill and the car starts to slow you press the pedal down further, right? That gives a signal to the tranny that you want to go faster than its capable of going at the moment, so it down shifts and you begin to accelerate. Since the cruise control simulates your right foot, the speed at which it reacts to stimuli will affect the reaction by the transmission to what the cruise is telling it. Ok, cut the crap - which one does better? You know, its a tough call. At higher speeds the Area 451 Parts model seems to adjust the speed a bit slower so when you hit a steep hill and the speed starts to drop, it takes a bit longer to change gears (drop to 4th) and waits longer before it shifts back up (to 5th) after you've crested the hills (remember, the cruise doesn't directly say when to shift, it just gives "hints" to the transmission by how far it presses the pedal) so it results in a smoother ride but sometimes in the "wrong" gear. The MDC unit causes the gears to switch more often which helps keep the speed steady, but the constant shifting gets a bit annoying. Most people in manual control would keep it in 4th until the hill is finished and the car can comfortably handle 5th gear again.

Which brings me to a huge point and difference between the two:

The MDC for the 451 will work ONLY in automatic mode. This is different than the version for the 450 which would work fine in both modes. The Area 451 Parts version does work perfectly fine in both modes. The shifting discussion is moot for the 451 if you manually control the gears. In manual mode with the Area 451 Parts cruise, you can avoid overshoot and choppy drive at high speeds almost entirely by just manually controlling the shifting rather than relying on the automatic transmission. I hesitated from even putting a transmission comparison in this because its NOT the cruise controlling the shifting. So you'll get the same choppy or sluggish ride without a cruise if you were to hold our foot steady (or not) going up the hill. The difference is a human will always react quicker and better to hills than a computer can. At least one using PID loop technology (fuzzy logic would be faster and more adaptable, but increases the chances you crash into a pole or your car rises up and overthrows the human race).

So, which is better overall? From what I've seen and tested there's no question. The new Area 451 Parts cruise control is simply a better product all round with one catch... its not yet available.

A disclaimer of bias. People have suggested that SmartieParts and the "new" company (Area 451 Parts) are working together. That's not technically true, but its not false either. The OWNER of SmartieParts (me) is involved in the Area 451 project... the companies are separate. So bias, yeah - you bet. But those that know me know that I'm a straight shooter and tell it like it is. The reason for working on the Area 451 project was to ensure steady supply of a popular product, not to necessarily make a better one. It just so happens it achieves both goals. For years I've had trouble keeping a supply of MDC cruise controls in stock, to the point that some people have waited in excess of 3.5 months at certain times. This restrictive supply keeps prices high and availability (and my sales) low. I don't think its deliberate - or even their fault - but it is the way it is. Hopefully we can change that.

So if you have a 451 and want a cruise control now, I have a few that I can sell NOW. If you can wait until August, then there will be a 2nd option. If you're in between... I suggest you contact me sooner rather than later because once these 2 or 3 MDC units I have here right now are sold... well, we're looking at 4-6 weeks or more before stock arrives.

Any questions at all... anything I missed, or anything you're curious about... as long as its about the cruise (and not trade secrets or sensitive business issues) I will be more than happy to provide my candid assessment of either or both products.

If anyone wishes to test drive either and see for themselves, I'm in the Kelowna area and I'll be happy to take you for a spin!

- Steven

[SCHMART]

thats exciting news

[Nextourer]

Sweeet! How close is the one you tested to the production version (Area 451)?

[MikeT]

Very interesting discussion.

[dancote]

If you can wait until August, then there will be a 2nd option.

August 1st, I hope

[SmartieParts]

The original target date for the new cruise was July 1. It is, in my estimately, highly unlikely that target will be achieved. It was a number drawn from a hat so the thought that its going to be even close is kind of fortunate.But I really don't have an ETA for people that's anything more than an insider's guess. - Steven

[Harleyduo]

Steven, Thank you so much for an incredible explanation. This should also help with people's expectations of the cruise control so that they can know EXACTLY what to expect and what is "normal" once they get it installed. I suspect that many people might panic if they suddenly experienced an 'overshoot' and they had never experienced it before. If they are like me, they would immediately feel that it must have been something they did WRONG during their installation. Now, everybody who reads this should be able to understand that it's most likely due to the car's lesser power than previous cars they may have experienced with cruise control. I'm wondering if the company might want to make sure they include such an explanation in the packaging information, or with the online instructions I've read that will be available, or at least in a FAQ section. I continue to be a huge supporter of this ambition and admire the way all the principals have been so 'straight' with us perspective buyers. Keep up the good work.Ron

[SmartieParts]

Thanks Ron!I agree overshoot should be discussed in their materials in one form or another. Pretending it doesn't exist is a mistake I think. Like I say, it technically is inherint in any automotive cruise control in any car in use today, but its probably so small you never notice it. You avoid it by simply pressing the pedal to make the car keep up... but if the car won't keep up, then...Incidentally, it can be tuned to lessen overshoot by adjusting "P" (in the P I D equation), but then you end up with pulsing and that's annoying. Striking the balance is why so many test runs were required in development. If you read up on PID process control loops, you'll find the general concensus is that the "ideal" tuned curve always has a little overshoot in favor of oscillations.So... 95 96 97 98 99 100 101 102 103 104 103 102 101 100 100 100 100 100 100 100 100....instead of95 96 97 98 99 100 99 100 99 100 99 100 99 100 99 100 99 100 100 100 100 100 100 100...if that makes any sense. And again, that's only when recovering from an "event" such as a hill where the car (not the cruise) was unable to hold the set speed. - Steven