So large BMW and Mercs with 6 cylinder + engines built without compromise drive well with DBW - shock horror..................................
Now back to the real world of 4 cylinders or less, small capacity, built to be frugal and achieve the lowest emissions, what do they drive like? Stifled and dull?
ECUs programed to assume any throttle movement beyond its preset limit is presumed pilot error so waits a preset period before reassessing whether to accelerate on our behalf.
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Not my experience Dox, DBW works a treat in my Mondeo.
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Not my experience Dox DBW works a treat in my Mondeo.
Is that the 1.0 or the 1.3 mondy?
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Now back to the real world of 4 cylinders or less small capacity built to be frugal and achieve the lowest emissions what do they drive like? Stifled and dull?
But is it really accurate to blame DBW throttles for the dullness that these types of cars exhibit? Do we really think that if they had cable throttles they would be any less dull?
If DBW is so bad then BMW and Merc would leave it to the washing machine cars and fit cable throttles in their performance orientated cars, but they don't, which suggests that DBW isn't really the source of the performance problems exhibited by a 1.2 Micra.
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A good system will modify the throttle response depending on the gear selected.One of the advantages of FBW technology.
This is an important point, I'm surprised it took so long to come up. The programming can govern what the response is dependent on several parameters not just the pedal position. The same principle applies to FBW aircraft which have 'protections'.
A simple example on my car is that it cuts the throttle if I apply the brake, regardless of the pedal position, but it doesn't prevent me applying the throttle if the brake is already pressed, which I usually do on hill starts for example.
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A simple example on my car is that it cuts the throttle if I apply the brake regardless of the pedal position but it doesn't prevent me applying the throttle if the brake is already pressed which I usually do on hill starts for example.
I'd have to presume you drive an auto and left foot brake rather than having 3 legs........
;o)
I've actually caught the brake pedal when accelerating away from a roundabout whilst wearing large boots and towing a laiden trailer, the resultant stall accross a roundabout at rush hour was far from fun! VW modified the software diue to lots of complaints
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I can only see FBW as a good thing. It makes cars much easier to build for lhd and rhd, for instance.
My last car was a 306dt, and the heat of the engine gradually cooked the cable, making it very stiff, and the pedal action very heavy. It cost the better part of 3 hours labour to replace due to the circuitous path the cable took from pedal, up one side of the engine and (ISTR) down the other. No such problems with my current FBW Focus.
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Hasnt every car with EFi got a drive by wire throttle in some form or other?
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"Hasnt every car with EFi got a drive by wire throttle in some form or other?"
No. not by a long stretch. Efi generally meters the air inlet quantity and injects the appropriate amount of fuel. DBW is not necessary at all.
Edited by Hamsafar on 02/10/2009 at 20:50
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It cost the betterpart of 3 hours labour to replace due to the circuitous
>>path the cable took from pedal up one side of the engine and (ISTR) down the other.
My old 306dt was exactly the same. A six monthly scoosh of WD40 inside the cable used to free it up nicely. Being a Fifer, I always look for the cheapest solutions :-)
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>>I'd have to presume you drive an auto and left foot brake rather than having 3 legs........
Neither ;-) Once you're used to it its instinctive to use the right foot on both pedals. Easier for hill starts than reaching forward for the handbrake. There are some cars where the pedal arrangement makes it difficult, but the CRV isn't one of them.
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Incidentally, I've not had a throttle position sensor fail but I have had a couple of throttle cables let go - one on a relatively new Audi.
The 'response' point somebody mentioned is an interesting one as well. You could design either option for a 'nippy' response. I have wondered in the past whether Ford used to do this quite deliberately. The Cortina, Sierra, Fiesta and Escort/Orions I had in the old days all needed very little prod to feel lively, in contrast to a Polo, Golf, Cavalier, Carlton, and Audi 80/100. Ford knew their market in those days and the Ford repmobile was usually a bit quicker than the equivalent Vauxhall and I suspect it was made to feel that way as well.
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If I remember correctly, cable throttles had a cam shaped guide on the throttle spindle to give non liniar response, and I assume DBW throttles are programmed similarly to give a lively response.
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Having driven trucks for far too many years, the cable throttled motors were always more instant in response, more satisfying too.
It might just be that modern DBW trucks are far more emission controlled, hence apparently much more powerful trucks are really so strangled that they are seemingly seconds behind in response times...and then it's nothing to write home about when the surge eventually arrives, as thousands of car drivers will testify to as they wait interminably for that modern truck to clear a junction/roundabout.
Honest we don't really mean to take for ever to get going, these new trucks have no 'guts' at all, though are pretty good at keeping motorway speeds uphill strangely enough.
Our pick up is DBW whereas the similarly engined Landcruiser was cable...there seems very little difference in feel to me, but i'm convinced the mechanically injected L/C would pull from lower revs..then it was manual so it's probably an illusion as well as rosy remembrance.
The 96 MB is cable throttle as well as cable downshift for the box, a smoother car i haven't driven since XJ6's.
Oh and as for DBW steering...not on any car i'll ever own.
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Oh and as for DBW steering...not on any car i'll ever own.
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Still use steam trains and piston engined aircraft, GB? :-)
I agree about DBW steering, but DBW brakes are on the way.
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Still use steam trains and piston engined aircraft GB? :-)
Rarely fly Navy, can't stand the herding; train wise i'm still a Deltic devotee at least for the wondrous sound..thats done it i'll have to fire up Youtube for my fix.
Won't be any DBW brakes on a Hilux in my lifetime i'll wager..;)
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My last two cars had FBW throttles, and I never had any problem with them. The Accord responded crisply to the throttle and I never had any reason to complain about it.
My current 335d is a different kettle of fish altogether. Being an automatic, any problems with the throttle are well and truly hidden by the gearbox. Depress the loud pedal and there is always a moment of calm while the gearbox decides whether
1. You just want a bit of extra speed, so it stays in the same gear
2. You need a bit of extra poke, it drops a gear and you you end up gathering pace at a significant rate or
3. You're being a bit of a spanner, so it'll quite happily drop two gears, open up both turbos and you end up driving from the back seat looking at the sky.
It's really quite intoxicating....except in the wet, when it can be quite a handful if you're not ready for it.
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My 1999 Saab 9-3 diesel had a FBW throttle. There was no problem with throttle feel and response on that. Any lack of response was down the engine's turbo lag.
FBW throttle enabled me to fit cruise control myself by just buying and plugging in a new indicator stalk. Cost 25 quid for the stalk with cruise buttons on it and took about 15 mins to fit; but had it been ordered as an option on the car from new the cost would have been about £300.
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The 96 MB is cable throttle
Odd, my 94 E320 definitely has a drive by wire throttle. Maybe due to the 5 speed automatic.
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Odd my 94 E320 definitely has a drive by wire throttle. Maybe due to the 5 speed automatic.
I think you will find yours is a hybrid - cable from pedal to a rheostat where it becomes fly-by-wire.
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I think you will find yours is a hybrid - cable from pedal to a rheostat where it becomes fly-by-wire.
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Just had a look at mine, throttle cable goes to inlet manifold and where it pivots the gearbox downshift cable comes off the same linkage, thats with the standard (poverty spec so i'm told.;) 4 speed.
Don't tell anyone BP, but i'm a little envious of the 5 speed in yours (not the rest of the electrickery that often accompanies it on the options list though), had that box in a 320 estate, as you know 1st is only used when you floor the throttle from standstill, the acceleration that follows is quite breathtaking, possibly supercar of the time standard.
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Don't tell anyone BP but i'm a little envious of the 5 speed in yours (not the rest of the electrickery that often accompanies it on the options list though) had that box in a 320 estate as you know 1st is only used when you floor the throttle from standstill the acceleration that follows is quite breathtaking possibly supercar of the time standard.
If you think the standard car was quick, you should try one of the Hughes of Beaconsfield / Turbo Technics twin turbo jobs.......
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If you think the standard car was quick you should try one of the Hughes of Beaconsfield / Turbo Technics twin turbo jobs.......
I'll bet they were superb, but it was the initial thrust that i meant up to say 30mph, almost instant as 1st gear on that 5 spd box is low.
There was a very amusing chap on one of the marque forums that tried all sorts to get his twin turbo'd coupe to run right, in the end i seem to remember he sold it having never got the thing to run properly.
Don't hear of many about, though i see once in a blue moon a 500E saloon come up for sale, now that i could live with and put up with the LHD...as an aside there is one linked on 'barryboys' in Russia that has been barried big time, extended snout, different headlights, spoilers the works, criminal ruination of one of the finest performance saloons ever produced.
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ISTR recall Roger Jones (former regular poster over in tech) had one of the twin turbo E classes. A real flying machine in its day.
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A simple example on my car is that it cuts the throttle if I apply the brake regardless of the pedal position but it doesn't prevent me applying the throttle if the brake is already pressed which I usually do on hill starts for example.
That's better than the VAG system which comes over all confused and sticks the MIL on if you dare to try and heel and toe or left foot brake for example. It can't handle throttle and brake inputs at the same time at all. A bit rubbish really, although in fairness the system does work well in every other respect.
If the likes of the "driver focused" GTIs and R32s were the same (and I have no idea if they are), it would be a major limitation.
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My wife's 1998 Passat TDI is a FBW with 158K on the clock. Never given any trouble and feels fine to drive.
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Sorry to bring back an old thread, but;
preview.tinyurl.com/y9v34v5
As you can see from the technical description, SBC is, effectively brake by wire, and in normal circumstances, the brake fluid pressure in the master cylinder doesn't travel anywhere beyond the Y1 and Y2 solenoids - the brakes being applied by the hydraulic pump in the SBC unit.
The brake fluid pressure in the master cylinder, in normal use, serves only to give some kind of simulated pedal feel to the driver.
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SBC is effectively brake by wire
Isn't that MB system flawed by having a limited number of applications (brake pedal applications) before requiring replacement at some huge cost...which i understand MB have given occasional goodwill depending on previous service history.
I'm sure i've read that the system has now been discontinued, but may well be wrong in that.
I'm sure the system is fantastic when it's working well, but why was it needed in the first place, MB brakes are usually well up to the mark in every vehicle they made proir to this SBS fitment.
Not saying it's not superbly clever stuff mind, just overkill.
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>>Isn't that MB system flawed by having a limited number of applications (brake pedal applications) before requiring replacement at some huge cost...which i understand MB have given occasional goodwill depending on previous service history.
Yes, there have been problems with it.
My main reason for posting the link was to show how completely the link between pedal and brake had been broken on cars sold in the UK - until I saw the system schematic diagram, I had not fully realised this aspect of the system's operation.
>>I'm sure i've read that the system has now been discontinued, but may well be wrong in that.
I think you're right, but, I wouldn't bet against an improved version of the system appearing again soon.
>>I'm sure the system is fantastic when it's working well, but why was it needed in the first place,
Among other things, it can talk to other systems on the car, and optimise the brake force distribution both fore / aft and left / right, it can pre-fill the calipers on throttle lift of, saving vital time in emergency stop situation, and lots more...
>>MB brakes are usually well up to the mark in every vehicle they made proir to this SBS fitment.
>>Not saying it's not superbly clever stuff mind, just overkill.
So, development should just stop?
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So development should just stop?
Thanks for those answers NC.
As regards development, i'm all for it but it should only be put into production vehicles once it's perfected with a useful life expectancy, which something like brakes should mean 12+ years of trouble free use as we would expect from current braking systems.
I can see where it would have great potential for linking with car control systems like radar controlled emergency braking and other handling systems etc, probably excellent life saving progress once perfected.
I do however think that disconnecting something like brakes or steering perish the thought from direct linking does have the potential for disaster when vehicles become older and suffer inevitable neglect and amateur tinkering.
On that subject it will make it even more imperative to stay with either main dealer or competent specialist indies for servicing of such things, making vehicles so equipped very expensive and possiblty even more troublesome in later life.
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12+ years of trouble free use as we would expect from current braking systems.
On that subject it will make it even more imperative to stay with either main dealer or competent specialist indies for servicing of such things making vehicles so equipped very expensive and possiblty even more troublesome in later life.
As I have said before on here (and was attempted to be shot down in flames....) you will not see 12 year old cars in 12 years!
the more of the technology that gets loaded onto cars, the lower the age expectancy becomes.
We already had perfectly good cars, with 'minor' faults being scrapped, due to being uneconomic to repair - cars that 10 years ago could have been repaired for next to nothing after a trip to the local scrapyard.
the way things are going, we will be lucky if cars last much over 7 years of age, before they become unrepairable, simply due to cost.
If you think im talking carp, think on the SBS system, to fix those when you have used up the maximum pedal presses, you wont see much - if any - change out of £1500.
ECU's already a grand each in many cases - some sensors not far behind that..
£2000 repair bills are already common, for faults that never existed a few years back.
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you will not see 12 year old cars in 12 years!
Agreed, it's not as if one £2K bill at 10 years and you've got another 5 years of just servicing, you could get a £2K minimum repair every year or less on a car worth peanuts...where do you draw the line.
The further this goes the more i'm convinced i'll end up with either a Kia with it's warranty and fixed costs and term or keep relatively simple old bangers as long as possible.
Even more glad i had the pick up rustproofed:-)
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I think this 'beyond economic repair' thing is extremely flawed thinking.
A friend just replaced a perfectly lovely A6. 70k on the clock, immaculate, poncy leather interior, Bose stereo etc etc. It had needed an EGR recently (cost £900 I think) and had needed an aircon repair (£250). He thought it might also need a new clutch soon (likely £1000) and possibly a new steering rack (was making a slight sound, again say £1000) so he got rid.
Thing is, the car was worth about £7-8k, but instead of spending £2k and having it as good as new, he traded it in and now is spending £500 every month on the new car and a balloon at the end as well.
To me that's man maths.
The £2k repairs are painful, but they were still possibilities in the future, not reality, and only equated to 4 months payments on a new car, whereas the new car is £500 out of your account each and every month. Even including the £1400 or so he'd spent recently, he would still have been quids in within 6 months if he'd kept it. But it wasn't 'worth it' on a car only worth £7k.
To be fair, I think he wanted a new car because he was bored and because he wanted an auto, but that wasn't how he justified it.
I think the economic argument normally rings hollow, either because a new car is so massively expensive, or if it isn't, then you are exchanging a set of known faults for a whole new set of unknown ones.
Just my opinion. G
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