- This topic has 49 replies, 34 voices, and was last updated 11 years ago by alaric.
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cars in deep water
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SaxonRiderFull Member
In what sort of depths can cars generally drive without stalling or getting destroyed?
I was just watching a video of the floods in Russia, and Ladas were driving in water that went comfortably past the doors sills (i.e. at least 2/3 of the way up the tyres). At the same time, a friend’s Ford Focus was written off because her and her husband drove attempted to drive through a 6″ pool of water that had formed on their road.*
*All depth claims are approximate.
CaptJonFree MemberDiesel vs petrol
modern computer controlled cars vs old ‘electrics’
hexhamstuFree MemberDepends where the intake is….. also depends if it’s a diesel or not as ignition leads etc will short underwater but a diesel with a mechanical fuel pump will be fine.
Fresh Goods Friday 696: The Middling Edition
Latest Singletrack VideosFresh Goods Friday 696: The Middlin...DracFull MemberVariants to consider.
Make and model of car, speed of vehicle, type of fuel and age of vehicle.
wwaswasFull Memberdepends where the water goes.
a lot of modern cars with encapsulated engines have an air intake very low down at the front of the car – basically water gets sucked in and then the engine gets a hydraulic lock.
I used to be able to drive my Triumph Herald with water flowing over the bonnet and up the windscreen if I kept a bit of speed up. I did thjen have to take the drain plugs out the floor to let the water out and change my socks though – the door seals were rubbish.
molgripsFree MemberSome cars have the air intake low down behind the bumper, apparently to take in warmer air from near the road surface, but it means they can’t drive in more than 8″ of water. It’s worth checking where yours is!
As for diesel vs petrol – old style diesels can run under water aside from the air intake, but new ones would probably short out all sorts of electrics and sensors if you submerged them.
SaxonRiderFull MemberDo all diesels have mechanical fuel pumps? Like, could I take my 2000 T4 2.5 Tdi and drive it through some substantial body of water?
CaptJonFree MemberSaxonRider – Member
Do all diesels have mechanical fuel pumps? Like, could I take my 2000 T4 2.5 Tdi and drive it through some substantial body of water?Yes, but it will only work if you film it and promise to post the results on here.
hexhamstuFree MemberMost diesels have a mechanical high pressure pump and a second less powerful ‘lift pump’ in the fuel tank. So in theory yes you could drive your T4 through substantial water BUT it depends where the intake is as sucking in a load of water is v.bad. Also who knows what other sensors are liable to malfunction on new cars. Drive by wire throttle etc.
philconsequenceFree Memberthe weekend after i bought a X-reg skoda deezil there was some flooding down in dorset and i drove it through a good 2 1/2 foot deep ‘puddles’
i’ve never been so chuffed with a car lol
alpinFree Memberi once tried to drive my old man’s rover through a ford in Kent. i made it half-way before the car died.
had to be rescued from the local landlord and was applauded by on-lookers as i was towed out.
the car sat on the drive for 4 weeks before it would run again. took ages drying the air filter thingy.
12 years later the old man now sees the funny side of it…
nickjbFree MemberYes, but it will only work if you film it and promise to post the results on here.
He’s mine softroading through some water:
[video]http://www.youtube.com/watch?v=xsPbtjK9hqE[/video]
The electrics are delicate enough, I doubt the water is very good for them… but it was fine
sweepyFree MemberI used to take my old peugeot 305 diesel van through water that went over the bonnet and up the windscreen. Smelt like hell afterwards
almightydutchFree MemberA fair few years ago now but when myself and a work mate left one day, the local river had burst its banks. No other way home than through the flood water which must have been about 80 yards long.
There was a tractor pulling one vehicle out the other end but being the cock sure teenagers we were at the time meant we felt the need to make it through without help.
So me and me mate in my Nova and a mate in his metro behind decided to go for it. Somehow we made it through but the metro didnt. God only knows how, as I was operating the pedals under what seemed like 6″ of water, my passenger had his hand out the window playing in the water which was almost level with the window itself. The car always stunk of the river after that
2nd gear, slipping the clutch like mad, I think the bow wave we created helped to keep the electrics dry so we made it. Matey in his metro didnt have the speed we did which I think was half his down fall, also we believe the Dizzy on his metro was located further down unlike the Nova where it comes directly off the end of the cam.
happy carefree days!!!
neninjaFree MemberSome cars have the air intake low down behind the bumper, apparently to take in warmer air from near the road surface
Why would they want to do that? I thought cooler air gave better performance as it’s more dense.
molgripsFree MemberDo all diesels have mechanical fuel pumps?
Old diesels had a thing called the injector pump, which distributed a squirt of fuel to each injector as the engine rotated. Driven off the cam belt in sync with the crankshaft. The injectors were just spring valves so when the injector pump squirted, the valve opened and sprayed fuel in.
Most (but not all*) now are common rail, which means the cambelt driven high pressure fuel pump pumps fuel into a sort of tube, and the injectors are now electrically operated valves that let fuel out of the tube into the cylinders. It works much better but the injectors are less reliable being complicated piezo electro mechanical things rather than a spring and a pin.
* the only other system I know of is the VAG PD engine, which VW stopped using in 2008 or so. Early ones had no injector pump, but each injector had its own plunger driven off the cam itself to squirt fuel in under very high pressure. This was reliable though being basically the same as the traditional kind, fully mechanical. The later ones have that same system but also a piezo electric valve to modify the squirt, giving much better driveability but again at a reliability cost.
Hmm, I seem to have typed out a lengthy discourse on diesel fuel injection.. I like diesels can you tell?
I thought cooler air gave better performance as it’s more dense.
Yes but with petrol, warmer air gives better fuel economy in normal driving, cos there’s less air it’s easier to compress and you need less fuel to get the right fuel/air ratio – this means less power overall. Less power means you need to open the throttle valve more which reduces throttle pumping losses.
johnnersFree MemberI’ve driven a petrol Mondeo through water well up over the sills, and up to boot level. I had to stop afterwards and bail it out. Took about 2 months to get the interior properly dry, and even then I traced later condensation problems (interior misting up for no apparent reason) to the spare wheel well still being full of water.
Anyone want to buy a car?
johnnersFree Memberwe believe the Dizzy on his metro was located further down
If it was the A-Series engine it’s at the front just behind the radiator, which probably didn’t help.
porter_jamieFull Memberyou write a modern(ish) car off if the topside of the floor gets wet, simply because that is where most of the electronic modules are. one for the engine, one for the trans if it is auto, one or more for the body.
if the carpet is wet, its a CatC, and up to the seats, defo a CatB because you are into airbags and all sorts.
neninjaFree MemberCheers molgrips – every days a school day. I never knew that.
MurrayFull MemberDon’t try it in a Citroen Xantia 1.8i (voice of experince, low intake). Wrote mine off at the end of a crap day.
speed12Free MemberIt works much better but the injectors are less reliable being complicated piezo electro mechanical things rather than a spring and a pin.
The majority of passenger car diesels actually still use Solenoid injectors. Piezos are starting to come in, mainly for emissions control, but on the whole solenoid is still king (much cheaper and as you rightly say, more reliable).
scaredypantsFull MemberYes but with petrol, warmer air gives better fuel economy in normal driving, cos there’s less air it’s easier to compress and you need less fuel to get the right fuel/air ratio – this means less power overall. Less power means you need to open the throttle valve more which reduces throttle pumping losses
1) Wot R throttle pumping losses ?
2) Why don’t they engineer this out, making the car run best at ambient (or is it that UK is comparatively cold, and in hot climates they reposition the intake to get “cooler” air) ?
3) Why don’t they have a nice big airbox that’s heated by the manifold or something ? – that way presumably all climates/conditions could be largely irrelevant and they could optimise against that “constant” tempmeesterbondFull MemberDrove my old diesel X-Type jag through a fairly deep (18″ to 2′) puddle. 4×4 sped through in the other direction, car stalled and I made the mistake of trying to restart it.
Did you know it costs about £8k to dry out and replace the engine in an x-type jag?
v8ninetyFull MemberHow NOT to do it in a Mitsubishi L200…
[video]http://www.youtube.com/watch?v=rZQAGAxq8lc&feature=youtube_gdata_player[/video]molgripsFree Member1) I’m sure CK will be along soon to correct me, but as I understand it the throttle body on a petrol restricts the air being sucked into the engine by making it go through a tiny gap. This means that the engine is doing a lot of work against turbulent air flow to try and fill the cylinder, which is wasted energy. Diesels don’t (usually) have this throttle valve, which is one reason why they can be more efficient. Really big petrol engines have to be throttled back a lot to drive at say 70mph, so sometimes it can be more efficient to drive at 80mph cos the increase in engine efficiency is geater than the extra losses of more air resistance.
2) Well there’s not much you could do. X amount of air in the cylinder need at least Y amount of fuel, whatever you do, otherwise the spark won’t ignite it. Again another way diesel is more efficient – because in a diesel it compresses the air to make it really hot then you can squirt the tiniest amount of fuel in and it still burns the same.
3) Dunno.. I wondered this. On a fiesta I had once there was a little heater thing in the airbox. Fuel economy geek Prius owners in the USA where it’s proper cold partially block up the grille so that the engine compartment stays warmer, then the engine draws that warmer air in. It works quite well apparently.
mastiles_fanylionFree MemberDepends where the intake is
Often this. No more fun than trying to ‘fix’ a hydraulic-ed diesel engine in a cold wet field 🙂 (Yes I know). Still, after limping home 20 miles and the engine eventually dying a death we DID get to replace it with a Rover V8 😈
It’s why you see 4x4s with snorkels…
konabunnyFree MemberFuel economy geek Prius owners in the USA where it’s proper cold partially block up the grille so that the engine compartment stays warmer, then the engine draws that warmer air in.
This is not uncommon in Russia in winter (not only Priuses).
mastiles_fanylionFree MemberAlso no uncommon with original Mini owners (but that was to stop damp getting on the alternator). As a kid we always used to see Minis buzzing around with a piece of card wrapped in tin foil strapped to the grille in winter.
SnSFree MemberI remember having one of them early Mini’s – I used cardboard to stop water getting at the distributor cap …..which was located directly behind the radiator grill ( ….proper numpty headed design).
Found out the hard way – every time rain sprayed into & through the radiator or I drove through a puddle – the car ground to a halt.
Chris
MurrayFull MemberThe Mini prototypes had the carb at the front and the distributor at the back. They suffered from carb icing so the production Minis had the layout swapped round. The rest is history.
DrPFull MemberRE the engine bay heat thing – IIRC some fancy cars have servo’d vanes on the grille, so they shut off in cool weather, and open when ventilation needed.
DRP
rootes1Full MemberIn what sort of depths can cars generally drive without stalling or getting destroyed?
depends where the air intake it..
fords are designed with a minimum wading height…
Pugs and Cits do not and is normally right low down under the bumper – not ideal for wading .. but then not something people do oftenin most cars..
My brotherinlaws wife wrecked his M5 by driving it through a ford… water in – smashed engined. hahaha!
scaredypantsFull MemberI remember having one of them early Mini’s – I used cardboard to stop water getting at the distributor cap …..which was located directly behind the radiator grill ( ….proper numpty headed design).
Found out the hard way – every time rain sprayed into & through the radiator or I drove through a puddle – the car ground to a halt.
I used to drive along the M62 quite often in my mini – if overtaking a big lorry in the rain you got about 5 seconds to complete the pass or else the thing would start to cut out 😆(@ DrP: ah, I assumed the closey-grille thing was to do with aerodynamics)
rootes1Full MemberI’m sure CK will be along soon to correct me, but as I understand it the throttle body on a petrol restricts the air being sucked into the engine by making it go through a tiny gap.
That is why it is called a ‘throttle’ 😉
Actually some BMW engines do not have a throttle in the traditional sense and in operation engine speed is governed by varying the valve lift to control the air fuel mix let into the chamber – though they still have a throttle plate for initial startup but after starting it stays wide open. (BMW Valvetronic)
this is more like a diesel where you control the fuel feed to control engine speed rather than restricting the air flow.
ssboggyFull MemberNot a car but the water looks pretty deep!
[video]http://www.youtube.com/watch?v=3mr_pCrhTkk[/video]
bencooperFree MemberThe Stalwart is my favourite example of a certain kind of British engineering – a 9-ton amphibious truck that can happily do that kind of thing, but the transmission explodes if you go around too many corners 🙂
alaricFull MemberThe rule of thumb for cars is the bottom of the wheel rim, 4 x 4’s the top of the rim.
You may get away with more, you may carry on running, but there are other factors than sudden failure to consider.
On my Mitsubishi, for example, there are breather pipes for the front and rear differentials – the front one was piped to the very rear / top of the engine bay. The rear, however, was only piped as far as one of the chassis crossmembers, that was open in the rear wheel arch – so in about 18 inches of water you’d fill the diff with water!
molgripsFree MemberRootes1 – sounds good, I thought Fiat were the first people to do that.
The other exception would also be direct injection petrol like the VAG FSI/TSI ones. Not sure how little petrol they can inject in though so they may need a throttle valve too. Probably have one for when it’s cold too.
Some diesels have throttle butterflies too to force more EGR for emissions purposes.
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