does having a engine retarder on equal a better fuel consumption my theory being the more you slow down the more you have to accelerate but the crowd im joining on monday say retarder on all the time (logistics here i come) any veiws me personally only use retarder on country roads and when i cant be bothered to lift my right right leg
electro magnetic retarders are excellent, been fitted to coaches for many years, save much brake wear.
Some trucks now fitted with them (extra spec?), can’t understand why they haven’t been standard instead of exhaust brakes which are, lets face it, with the possible exception of the Volvo jake brake, like a dog p’ing in the snow.
Retarders generally work on the prop shaft, not the engine.
As for affecting MPG, its the method & amount of use of the “go” pedal that affects that, not so much the method of slowing.
thats one of the reasons i dont like them anything but the prop going and you do feel it so a companys insistance on constant use 
I cant think of/dont know of a logistics company that has retarders fitted as standard, im thinking you mean engine brakes. Youre talking a couple or three thousand pounds for a retarder (which are absolutley fantastic). What kind of truck are you going to be driving, cos im thinking youre getting an engine brake, which you could get away with being on all the time. If youre on for a big national firm, i could see some spotty git saying ‘yeah mate theyve got retarders fitted’ when all they’ve got is an exhaust brake. Im just thinking this cos you said logistics company, and im thinking someone like DHL, and i would bet they wouldnt have retarders, just exhaust brakes, anyway, pub shut, me, bed…
always called them retarders /exhaust brakes will be driving 340 volvos
Sounds like they are Exhausters rather than Retarders then, in which case leaving them on when you’re loaded is no problem at all. I run with mine on in those circumstances and it kicks in whenever I take my foot off the throttle, hence saving fuel by choking off the engine, and saving your brakes by holding you back on long downward inclines. It’s not strong enough to slow you much if the revs are at cruise level, so it really only does it’s thing when they start to raise as you overrun coming into junctions or on the aforementioned hills, hence negating the “more fuel because it slows me down so I have to accelerate again” effect.
Mine had a problem just after MOT so it was switched off for a few days - the amount of extra fuel used was small but noticeable. When you think that just 0.1mpg adds up to over £500 a year…then extrapolate that out to a large fleet…you can see why they are stating it as a preference.
You’ll note, however, that I said when you’re loaded. Having driven a couple of our 04 plate Volvos, they were fine empty as well, but the newer ones may be better and they do tend to vary from wagon to wagon and model to model. My Stralis exhauster will put me through the windscreen if I put it on full whack when I’m empty skelly, and cause a great deal of discomfort when I’m pulling an empty box…So I find it best to leave it off when empty…on one click when loaded empty…and on full when loaded. You’ll just have to experiment with your particular truck, though.
Hope that helps.
Use the exhaust brake according to whether you are empty or loaded and the road conditions. You are entirely responsible for the safe operation of your vehicle - NOT somebody driving a desk.
perhaps the best thing to do is ensure you read the operator/drivers manual of the truck that you are expected to drive.
i have a scania with a retarder system that operates through the gearbox, the instruction book says not to use the retarder in slippy or icy road conditions as the drive wheels could lock up causing the vehicle to jacknife, i have already felt this happen when driving in the rain after a long dry period (not this year then).
it sounds to me like the system you have is the VBS - volvo braking system and usually comes with 2 settings, the first is the usual exhauster brake but the second level is a much more fierce system of exhaust retardation and i’m not sure if volvo have updated their system but on the early models the worst thing about this system was that the brake lights didn’t operate with the VBS and it was like applying the brakes which did cause some concern to those behind you.
VBS, VEB, Retarder, Intarder and butterfly exhaust brakes all do the same thing. They are there to make life easier for the brake linings, bearings and tyres.
I have a Volvo and if you use the cruise with the engine brake, all you have to do is steer the thing. They only work if you are in the right gear for the descent.
Coming down windy hill in top gear with the engine turning at 1400 rpm will just make a noise. drop it to 10th and let the revs build up to 1900 and you will feel the retardation.
I have had MAN with ZF Intarder. Voiths with prop shaft discs and Voiths working direct in the gearbox by pumping oil through small ports. I wouldnt drive a truck without one now
Wow, aren’t drivers spoilt today with their toys?
Friend of mine used to regularly descend from the Mont Blanc tunnel with his old F10.
Exhaust brake didnt work. Rented trailer brakes very often p poor.
4x2 unit on drums all round.
In those days you got it low enough down the box so that the engine would more or less hold it & took your time.
Couple of other points whilst we’re on exhaust brakes.
Newer automatic Mercs will automatically employ the EB and change down if speed increases beyond a given tolerance from the cruise control speed.
The 03 Actoss’s i’m currently driving (manual with electronic selection) have mostly covered about 550,000kms. I’ve noticed quite a few seem to display the same characteristics in that if you leave the EB on, but then go back on the throttle, there is a delay in the power coming on, there is a “pop” & the exhaust chucks out a very noticeable cloud of grey smoke.
Driveroneuk:
Newer automatic Mercs will automatically employ the EB and change down if speed increases beyond a given tolerance from the cruise control speed.
I-shift Volvo’s do it as well, have done since they were launched.
Driveroneuk:
Wow, aren’t drivers spoilt today with their toys?Friend of mine used to regularly descend from the Mont Blanc tunnel with his old F10.
Exhaust brake didnt work. Rented trailer brakes very often p poor.
4x2 unit on drums all round.In those days you got it low enough down the box so that the engine would more or less hold it & took your time.
I was always taught that you use the same gear to go down the hill as you would use to climb it. and what happened to giving way to a loaded vehicle climbing?
Wheel Nut:
I was always taught that you use the same gear to go down the hill as you would use to climb it.
me too 
and what happened to giving way to a loaded vehicle climbing?
doesn’t happen very often 
And you try and tell the young people today that… and they won’t believe ya’
Denis F:
And you try and tell the young people today that… and they won’t believe ya’
They might if they had to eat a handful of cold gravel before working a 26 hour shift down t’mill for sixpence a fortnight.
Now when I was a lad, we had it tough…
There will be four settings on the Volvo engine brake …Stalk on the right hand side …
1-3 ,1 being the lowest brake 3 being the highest …
Then hold the stalk down for and you get option B which is heavy braking …
If the truck is slowing down at a rate that is on par with you using the brakes then the brake lights should come on …
dieseldave:
Denis F:
And you try and tell the young people today that… and they won’t believe ya’They might if they had to eat a handful of cold gravel before working a 26 hour shift down t’mill for sixpence a fortnight.
Now when I was a lad, we had it tough…
gotcha 
Denis F:
gotcha
It’s a fair cop, but society is to blame.
Lots of retards in our office