'Modifications' banned

“The biggest problem with brakes would be fading. Cars are way way better than they used to be in the past but that's more of a formulae one driving style type problem which just wouldn't be appropriate on the road. 2ndry one is the brake fluid boiling. There are different fluids. I drove down the Glossknocker pass in a car once a long time ago and had no brakes to speak of when I got to the bottom. I'd guess all modern cars would do it easily now.”

Most cars have some form of ABS, running ventilated discs etc. The size and performance of these items is matched to the vehicle performance and use envelope. Add a performance increase (which is going to be used or you would not bother doing it?) and they are no longer matched and probably (speculation) not up to the job. Most modern cars have advanced ABS systems (not the old fashioned simple systems of yesteryear) which are linked into the other vehicle systems (transmission etc.) and all of this is out the window when you start playing around.

Fluid choice for the system is again linked to the type of system and the design of the internal components and the design of the valves and actuators etc. Again, fiddling is likely to result in a system performing in something less than optimum.

“Suspension - maybe the uprate the springs.”

And geometry (including different wheel/tyre combinations). Changes in compliant bush design (often stiffer). Reduced spring height (affecting overall vehicle dynamics) and changed spring rates – often variable rate. Shock absorber changes have always been the standard stock in trade for vehicle tuning, another area requiring extensive knowledge to achieve the correct results unless you are lucky or prepared to experiment and be capable of interpreting the results of any changes.

“Cooling. As Saab offered a power upgrade on a 95 without any effect on the warantee there doesn't seem to be a problem. They even pointed out that fuel consumption during some kinds of use would actually be better. I suspect what is actually happening really is that all cars are electronically limited. Saab normally offered a time limited power boost for overtaking. Some one working on engine management was wondering what to do about engine overloading when towing - from the engines point of view it's best to give the power that's needed. They can pick up when this is happening from engine data.”

I am prepared to stick my neck on the line here and say Saab are in a minority of 1 here. Certainly, most other manufacturers require modified cooling if you fit a tow bar (that is why they make them as kits). I know there are those who will claim it is a ruse to sell their kit, but you fit some spurious bar and start towing/using more power than was intended, then don’t bother trying to complain your engine broke to soon ‘cos I would have to agree that you broke it through misuse!

“There seems to be a lot of scope on diesels for increasing power by changing the limit and or mapping but there were a huge array of possible power levels available out of Rover V8's as well. I toyed with the idea of having one fitted to a Shogan and it was a case of what power would you like sir up to silly numbers. We found a nice fairly cheap Landcruiser instead.

The problem with using the power however on modern diesels would be very likely to be the clutch. Once upon a time the diesel engine was entirely different to the petrol one and would have a larger clutch - not so now they use springs and things to try and absorb the torque”

Diesels are not petrol engines (they have very different power/torque output maps). The internal engine components are also stressed in very different ways. Rover V* engines are a very old design and a huge amount of empirical tuning information is available. I have one fitted to a sports car that is tuned but it is an old car and the engine was altered along with a lot of other items on the car appropriate to the power output of the engine. Getting huge power outputs from these engines is not a simple or trivial matter. Clutch modification is included in transmission in my book and the mods run to a bit more than some springs….. You really think so?

All of this just adds weight to the argument against letting people make changes when they are fiddling with stuff they clearly don’t understand fully. After all that, what happens when you tell the insurance company it is no longer standard?????

Mark

I spent about 10 years working mostly on ABS Mark. No point on me commenting. There is a lot of my software on the roads still currently. Bosch have made an excellent electronic ABS unit for a long time. Initially ABS was only fitted to more expensive cars. It's slowly drifted down the model range and for a significant period of time some of them were awful and will have caused accidents.

I have several tow bars fitted to different cars and so far no change to the cooling even when it's the oe part. As some mentioned they have to be approved anyway. I towed a caravan pretty often for a number of years but not on the cars that I have owned that had rather short clutch lives. 2 so far.

When I mentioned different I meant an entirely different physical design of engine, nothing to do with if they are running petrol or diesel. Audi had a lot to do with the change - they fitted a diesel injection unit in place of the distributor on a petrol engine a long time ago now and did little else. Yes they do have different torque characteristics hence the changes in clutch design and no longer just fitting a bigger clutch on diesels. I've had 2 fail and am well aware of how they work. In my view certain manufacturers are skimping to far on both these and gearboxes. However having said that torque at various engine revolutions and other conditions is largely under the control of the engine management on both diesel and petrol engines. Gas flow etc relates to the design of the engine and valves etc and is an entirely different subject. Toyota were the first people to really exploit that particular aspect but the engine was developed by Holbay. One of my cousins worked on it.

Rover V8's - all done in the engine management. The days of friction reduction and similar aspects on large engines like that are largely gone. Manufactures work to much closer tolerances now.

John

-

John, let me just say how relieved I am that you wrote the software in my cars ABS system ..... oh no! I drive a Golf, sounds like you never got near it.

You really should stick to commenting about things you have "real and relevant" knowledge about.

Mark

You mean you do - afraid I sincerely doubt that. And yes I have had nothing to do with the abs on a Golf. I'd hope that they still use Bosch units. Actually the ones that I have driven in a number of manufacturers cars have been pretty good for circa 12 years or so now. Not so initially on cheaper to mid range cars and over prior to that sort of date. Some were awful and others have had their moments but not Bosch more or less ever since they started producing them.

John

-

.

Mark,

Returning to your [rhetorical?] question:

Given that systems like this exist; I would imagine that "chipping" the suspension is quite feasible.

... I don't know "how exactly"

MichaelG.

Michael,

The systems have their origins primarily in F1 development I belive. They use a number of systems including magnetostrictive fluids etc. These allow the equivalent of variable viscosity fluid in the damper but these are systems I have no personal experience of as they are relatively new developments on road cars. I think developments have raced on significantly since these early systems and are fully integrated with the other vehicle systems (as mentioned in the BMW link you posted).

However, being able to modify the software still does not allow you to exceed the physical properties of the system which is were the problems start.

Mark

.

True ... and in the limiting case it's "the nut behind the wheel" that detemines success or failure.

Quite a few years ago, I did a RoSPA advanced driving course, and was lucky enough to have a Police Driving Instructor-Instructor take me for a couple of demonstration runs [one in his car, and one in mine] ... It was memorable for all the right reasons. [Regrettably, however: Not all Police Drivers are created equal].

MichaelG.

Michael, yes, and it will be interesting to see what happens when that particular nut is replaced by software.... not certain I want to be on the road with one.

Mark

There have been some very serious attempts at improving the reliability of automotive software Mark but true sometimes things go wrong. Fortunately they are usually trivial aspects but not always and sometimes no one gets to hear about them and they are down to a series of particular events happening at the right or wrong time depending on how you look at it and they get fixed quietly. Too much depends on the person or persons really that produce the stuff but simulation and real road testing in particular usually iron them out. This has been the case on ABS for a long long time. Engine management people didn't really think the right way as software became more and more complicated in their area. A good example is car engines loosing power at high speeds because the software chooses to save the cat for some reason or the other. Great at speed in the outer lane of a crowded motor way. They are lot more careful about that sort of thing now. I moaned about the stability control on a Passat that I had - kicking in when not needed which can be a bit disconcerting but safe really. I was at MIRA and one of the people who were responsible for the unit used was around. There was a discussion on ride and handling - oh they have just set the limits a bit too fine I'll reset them for you if you like. No thanks said me. However as has been demonstrated in a lunatic fashion on Top Gear the performance of these systems can be unbelievable if done properly. People shouldn't drive like that on the road so I forgive Volkswagon for leaving it as they had. The police shouldn't drive like that either. I do drive rather firmly which isn't the same as speeding etc. Many people don't.

Attempts at ruling out software faults by design have been around for a long time. In the automotive area these people have done lots. A first really on the automotive side

**LINK**

The company I worked for are pretty typical of why some of it falls on deaf ears. One aspect is pretty simple. Pundits get involved and say things like programmers make such and such a mistake when they use this particular construct so don't use it. In real terms they should be saying people who do make mistakes such as the ones they mention shouldn't really be working on what ever it is this way or some other method of them doing the job has to be found. The other aspect comes from higher management - time to market. They are not keen on anything that slows work down and development is expensive anyway In the UK that isn't due to the salaries of the people that do it. I've often wished I worked in Europe or the USA and Japan would even be better. I feel this aspect is one of the problems with the UK economy in numerous areas.

Michael mentioning ROSPA reminded me of a tail that indicates just how tough it is to produce a good abs unit. A man from ROSPA wanted a demo on a skid pan. Large flat bed truck fitted with a unit that has often found it's way into fire engines. The ROSPA man pointed out that things stop much more quickly when they are going sideways. The big problem with braking is that in the extreme you can stop and have no steering or take a bit longer to stop and have some steering. A nasty thing to balance. They will generally stop a vehicle more quickly than many drivers but up to now in many cases not as quickly as a formulae one driver who will leave very feint skid marks on the road by putting the wheels into critical slip. People can't really drive like that on normal roads really because the surfaces aren't consistent enough. They have done something about panic braking on just about all modern vehicles now. That has always been a bit of a problem on the ABS side. Once a wheel had gone well down it takes some time to recover and no brakes while it does. It has to hunt out the adhesion that is available all of the time it's active. Some do better than others in that respect - especially in the past. I prefer to check just in case.

John

-

Car ABS came after Truck ABS which was a development of aircraft ABS - and before that trains where it all started. For those interested, here is an interesting paper by Wabco on truck abs:

**LINK**

Doesn't add much to the debate about fiddling with ECU's but its interesting all the same!

Mark

I found it interesting Mark. Wabco was a very major competitor. Actually they really went to war with us and I had to smile when I noticed that they now offer what they had tried to get off the road one way or another. It was an ABS set up that is suitable for various axle configurations on semi trailers. Something Wabco were not that familiar with so were way behind on development. The net result of that and other aspects meant that the company managed to get 100% of the uk trailer market. Undefendable but it was always high. They also sold a lot because the support customers got was not just a little bit but one hell of a lot better than Wabco were prepared to offer.

ABS in the UK started independently. A few people in a small wing of Lucas nothing to do with aircraft systems at all. The initial unit was a mix of logic and analogue components that hung around for some time. That then went to micro controller. In the previous system a lot of the ABS intelligence was built into the control valve. It wasn't very clever at all. The work was switched to Girling at some point. Another Lucas company. There they went on to develop a car system that sold in relatively small numbers. Lucas were hell bent on closing down. They also developed a brake by wire system that was well ahead of anything anyone else had but it was thrown away when Girling was closed. They also produced systems for trains. That went too. The mico based controller carried on and then came a system specifically for trailers due to impending mandatory ABS legislation on HGV's. One of the major reasons for that was to stop trailer jack knifing. True the stop pretty quickly going sideways swinging the truck all over the place but also do a lot of damage.

Just adding a little to the Wabco leaflet. ABS generally runs through all of it main code 100 times a second. This includes checking to see if bits have broken or fallen off etc. Another time period that has been used is every 6 or 8 mSec. Much depends on the mass of the wheels on the vehicle and recovery rates etc. 100 times a second for instance is probably faster than the wheels on an HGV really need. We also offered a brake light powered system but tried to persuade customers to switch to permanent power via the ignition switch. Popular as ABS was retrofitted and stop light power was easy to fit. Great fun. The ECU had to be up and running and ready to do business in 100 mSec as that's how long it may take for the air to reach the brakes. It also checked that the processor was functioning sensibly in several areas during that time period. There was another processor in them that checked that as well independently and did nothing other than that. Most manufacturers hadn't bothered to do this.

The only thing that has ever worried me about them was fault codes. They happen but when ever I was sent to see a customer those that really did maintain their vehicles were happy with them. Odd ones but generally eventually proved to be a fault on the vehicle. No point me worrying 'cause those above tend to set what actually gets worked on.

John

-

You might try searching the name "Maxaret" - nothing to do with Lucas. And no software to be seen by the way.... This is the system that introduced me to ABS. Pretty certain Lucas were late joiners to the party and most of that would have been from overseas (TRW and their predecessors?).

Mark

Hmm, "Maxaret", that brought back memories of one lunchtime at RAF Church Fenton where we went (ATC) for air experience flying in Chippies.

They had a "Scrapyard" and I remember one of our mob reclaiming the Maxaret unit and the disc from possibly a Vampire oleo with visions or fitting it to the front wheel of his Rapide C. We all scoffed at the thought of hydraulic brakes on a motorbike - - - well, it was just after the "Benly" and just before the "Dream" hit our shores.

Regards Ian.

One of the engineers I worked with on Cessnas in the 1960s fitted the brake disk from a Cessna 180/185 in the front hub of his Norton (or was it the Triumph), in those days he raced his bikes, and found the discs a great advantage.

Ian S C

In the early 1970s when I was employed at the Mullard Research Labs we had an automotive department which was working on an electronic ABS system for cars. I believe it was taken up by Triumph.

Russell.

In the 1970's we used to have "ABS" Jaguar XJ12s as police motorway patrol vehicles. It was controlled by a box of kit in the boot, think it it was a Lucas/Girling unit but I can't remember for sure and was always referred to as a cadence braking system. The driving school instructors weren't that impressed as the manual cadence braking methods we were taught would beat the system every time and reckoned it would never catch on

Even bicycles have hydraulic disc brakes these days!

Neil

Liucas had GX the no software version on tomorrows world circa early/mid 1960's, It was very definitely being worked on at Girling in the early 70's and Lucas were working on it for a long time before it was passed over to them.

TRW are the company that eventually took them over. Up to that point it was always a purely UK company that also happened to have a number of overseas factories as well. Other names that people might have heard of and owned where Butlers, Smiths, CAV, Rotax and Simms. All that's left of Lucas now is the research centre and the 2 aerospace factories. There may be another that produced a lot of aircraft activation stuff but I suspect that has gone. They sold a lot of it and had kittens any time an aircraft crashed in case their kit was involved. I used to do some liason work with them and it was clearly being run down and no development being done at all.

I believe some of the content of this isn't correct

**LINK**

The people who worked on ABS and related items at TRW were a bit annoyed that TRW shut the Girling proving grounds and development centre as they were well ahead of them and tried to do something about it but failed. Me well I was sold along with a couple of other people. A few hundred development people lost their job. The Girling factory had it's roof removed to save paying rates.

It's generally reckoned that when they "disapeared" something in excess 25,000 jobs went with them. Slowly at first because apart from aerospace the sold of 1/2 and a bit shares of all of their operating companies to foreign ocompanies. A side effect of that was good way of getting people out of the pension fund so that they could take several 100 million quid out of it as it was well over subscribed. They also set up a company to import just about all of the car parts people associate with the name from Taiwan having quietly arranged for that to happen before selling any manufacturing facilities. They did it while the know how was about. That wing still seems to be around.

John

-