on the other hand if it didnt go "tssss" the car would accelerate as if the throttle was floored (turbo spins up, compresses air, more air into cylinder, more air through turbine, more compressed air etc etc etc) untill eventualy the valves go off in search of extra terrestrial life.
functional my arse !most seem to do it at tickover
Not a dump valve then, its physically impossible to activate (a real) one at tickover.
on the other hand if it didnt go "tssss" the car would accelerate as if the throttle was floored (turbo spins up, compresses air, more air into cylinder, more air through turbine, more compressed air etc etc etc) untill eventualy the valves go off in search of extra terrestrial life.
Nope, thats not how they work. They work on the pressure differential across the throttle plate, they only activate when the throttle is shut, not under high pressure in normal driving (though you can divert the wastegate of the turbo down a "screamer" pipe).
You can choose how loud a noise you want (though the quietest will sound very loud with a lot of air behind it), but with a decent sized turbo (unlike that on the 200sx above :)) you can still hear it pretty loud through a standard recirc valve. As mentioned several times they're functional, when you fit the correct one they dont cause running problems at all as someone claimed, and when you have a functionally modified car they're invaluable to save you a few hundred a year on turbo replacements (mine didn't have one as standard because it was only a low boost engine as standard). Having seen a few snapped turbine shafts and priced at £500+ a shot it's generally considered good practice to use some sort of valve. At the risk of sounding even more chavvy I'll point out I do have a fairly modified car, though it is almost entirely functional - it looks close to standard.
I hate some of the glitzed up bling machines you get, but really it's their hobby, they enjoy doing it and they'd never insure a powerful car so it's fair enough really. Its much the same as buying "upgrades" to bikes - such as people wanting headbadges, going for braided brake hoses which make no difference at all in the real world, going for carbon bars despite them being no lighter than aluminium....
In answer to the thought "I'm sure they do it on purpose" - yup, some of them do think its funny to scare people with the valve noise. Incidentally you can report it to the police who will warn them under some section of the law (cant remember what) and if they get got twice they have their vehicle confiscated. But please bear in mind that it could just be someone like myself - a perfectly amicable chap with an interest in cars who just happened to change gear when passing you!
Live and let live for christ's sake.
YOU dont have to like or understand it.
I bet they would have a few things to say about grown men in tights meeting up in the woods, if they weren't too busy enjoying their life.
😛
well, was more of a figure of speech really, rather than a literal descriptionNot a dump valve then, its physically impossible to activate (a real) one at tickover
you reckon "they" declare this sort of mod ?and they'd never insure a powerful car
well, was more of a figure of speech really, rather than a literal description
Ah, well in that case it's perfectly possible then - you need very little engine load to spool the turbine and generate damaging reflected waves of 100psi+ - fairly normal for them to activate after anything around 2-3K revs+ and 1/4 throttle. It is very common these days for 1.2 novas to have the fake version fitted. As well as flamer kits for the exhaust etc 🙁
you reckon "they" declare this sort of mod ?
Undoubtedly some don't as they see it as something that doesnt affect performance and think they'll get away with it, but then you cant buy and insure a ferrari without letting your insurance company know! It's actually not hard to find companies that will cover a very modified car quite cheaply - mine was only £500 a year with guaranteed valuation, new for old on all mods (including uprated gearbox with different ratios, different turbo, injectors, cooling, suspension components, completely replaced engine management system giving >50% extra power on an already group 17 car) etc... Though I suppose I was 24 at that point!
As Rich said, they're enjoying themselves in a way you dont understand. You enjoy yourself in a way they dont understand - lets all agree to be different and get on with enjoying ourselves!
flamer kits for the exhaust
WANTS IT.
(But you haven't got a car, RudeBoy, and you can't even drive, you stupid little idiot.)
Oh.
Rudeboy anxiously fretted over whether or not any more modifications could actually be made...
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Just out of interest, is it the cars themselves, that some people object to, or the 'type of people' that drive them?
cracking troll OP
makes you look like a bell end, but good troll none the less.
if i get this correct a car changed gear as it passed you and made a noise, this scared you enough to make you go on the internet and rant about it.
i would rather my car wen't psst when i changed gear rather than the 15psi shock wave hitting the turbo compressor wheel shattering it and possibly causing a fair bit of damage to the engine/cloud of oil smoke out of the back
coffeeKing,
i.e. when the throttle shuts, they reduce further reduce the intake pressure, running a turbo (on a carbeuretured car anyway) without one could (without knowing more about the engine in question i coulnt say exactly) lead to at worst a continued rise in rev's, at best a very slow throttle response as the engines revs drop slower than they would otherwise have done.
i.e. when the throttle shuts, they reduce further reduce the intake pressure, running a turbo (on a carbeuretured car anyway) without one could (without knowing more about the engine in question i coulnt say exactly) lead to at worst a continued rise in rev's, at best a very slow throttle response as the engines revs drop slower than they would otherwise have done.
I'm not sure what you were quite trying to say there, the sentence doesnt make sense to me?
It's a moot point anyway, as 99.9% of turbocharged cars are fuel injected, and usually port injected at that, fueling and timing is controlled by ECU, drawn in by air flow - if your turbo continued to boost with your throttle shut you'd know very little about it. I'm fairly sure the same is true of carb'd cars, especially blow-through type with the carb after the turbo.
zed - lol, yes that site is full of some very dodgy cars. But then its full of some seriously unpleasant people with very little going on in their life spitting vitriol about people they dont know as a way of feeling better about themselves. And no, I've never been featured 🙂
This made me chuckle a bit:
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Anyone knowing the original 6r4 knows it was undeniably a beast, if a little unreliable. Shame group B was banned.
Zedsdead, That barryboys site is genius!! 😀 Think this is my favourite:
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Shed of the year 2007!
Its a shame that is, the calibra was a fairly nice looking car for its year.
your turbo couldn't boost with the throttle shut
the flow of exhaust gasses would be to low to spin the turbines
the main reason for dump valves is to stop compressor stall and help avoid turbo lag, yes you could have an anti lag system fitted, but injecting unburned fuel into the turbo (by cutting ignition) isn't really going to do the turbo much good.
thats the reason why i have one on my track car.
Anyway, forget cars, vayns is where it's at:
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Pimp My Vayn!
I always liked the Lancia Rally Car (S4?) they used them for Rallycross as well, both supercharged & turbocharged, sucked & blew & then went Tisss
Never came across one on the road though.
To be honest some of the seriously modded cars like that vayn and the corsa dont get driven too stupidly, as the they cost too much to damage and often underinsured.
Its the halfords add ons that are a pain.
that said I was one when i was a yoof.
your turbo couldn't boost with the throttle shut
Which was the point I was trying to make and in the end forgot to say 😆
To be honest some of the seriously modded cars like that vayn and the corsa dont get driven too stupidly, as the they cost too much to damage and often underinsured.
Very true, that's partly why insurance companies offer large discounts to people who are members of owners clubs and owners of show cars.
That van is actually very nice and pretty tasteful. I like vans with a few visual modifications. I dont like this:
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No. That is nasty.
I quite like some of the more stylish mods. It's about expressing yourself, innit? It's the cheap, nasty ones that I can't stand.
I mean, look, she is so ashamed, she doesn't want to be identified:
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A sh1t car, made shitter.
Who said they were functional? My VR4s have recirculation valves so protect the turbos while making almost no noise. Makes sense to me.
OK. My rant was about 'boy racers' in modded saxos/106s etc. not the superior RS/EVO/track racer type (who I assume are more sensible and socially aware - sorry another sweeping generalisation).
I understand that it's the equivalent of driving around squirting passers-by with a water pistol and if it was just the once then I'd have a gentle smile to myself. But I get it at least once every time I set out and it always makes me jump and it isn't the same car all the time.
That coupled with the enormous exhaust pipe and the insistance on taking the engine to 5000rpm in the 150m from my house to the end of the road at 1230 in the morning grates just a bit. There's rarely any loud music to accompany this.
Don't they see how anti-social it is? If I start my car very early/late in the day I have a little grimace to myself about whether I'm disturbing someone's sleep. I certainly don't rev the bullocks off it and squeal the tyres round the corner.
However, in order to restore peace I have decided that it's just me getting old and grumpy and I shouldn't let it worry me.
BOAS you must live close to me, I have somebody who does that too, about 23.00 normally.
Its ok though. Come summertime, when people leave windows open, I plan to take my diesel round to just outside their house & leave the engine running to fill their house up with fumes before they get up .... midday should do nicely 🙂
Who said they were functional? My VR4s have recirculation valves so protect the turbos while making almost no noise. Makes sense to me.
Thats ok if your car came with one originally, it usually will be a recirc (and these days buried below 4 tons of cladding to keep it quiet). If your car originally came with no valve (low-pressure systems dont) and you up the boost pressure you should really have one fitted, the easiest option is to take a T off the intake. Its a lot easier than Ting in before the turbo too, ensuring its done on the correct side of the air flow meter etc.
But I get it at least once every time I set out and it always makes me jump and it isn't the same car all the time.
I'd suggest it's just you being overly sensitive 🙂
That coupled with the enormous exhaust pipe and the insistance on taking the engine to 5000rpm in the 150m from my house to the end of the road at 1230 in the morning grates just a bit. There's rarely any loud music to accompany this.
Yup, that is just damned antisocial. And these days people seem to enjoy being antisocial, like its some sort of "right". I make damn sure I creap into my estate at idle if I'm returning any later than 10pm, because its not fair on everyone else, as you say.
Don't they see how anti-social it is? If I start my car very early/late in the day I have a little grimace to myself about whether I'm disturbing someone's sleep. I certainly don't rev the bullocks off it and squeal the tyres round the corner.
True, and I think this is the main point indeed. And in this case you are right! When I had a job that started at 7am, so had to leave for work by 6:40am, and my car was off the road at the time so had to use my (rather loud) motorbike to get to work on each day for a bit, I'd push the thing out the garage, then start freewheeling it down the road (lived up a slight hill at least) before I'd then start the ignition once I'd got a few hundred metres down the road and up to about 20mph or so to lessen the impact of the noise it made.
People derive pleasure from all sorts of different things, and it's not up to us to tell them how to spend their money. But it is up to everyone to be socially responsible. I for one like loud music, and it's not the kind of music that most people would enjoy! Therefore I tend to go out to clubs, or listen at home when nobody else is around, or in my car on the motorway when there's nobody else to annoy. When there's other people around that may not like it to annoy, I turn it off or down.
In this respect you do come across a lot of the modded shopping trolley hatchback brigade that think it's their god given right to make as much noise as possible, as much of the time as possible, and for that they should get their wrists slapped! Personally though, if I derived enjoyment from ragging my car around someone's housing estate at 12:30 at night, I'd want my car to be as quiet as possible, so there was less chance of people hearing me do it and so less chance of the cops turning up! But maybe I'm too old and wise now 😉
I made a performance mod to my car a couple of months ago. I actually felt slightly dirty and ashamed...
If your car originally came with no valve (low-pressure systems dont) and you up the boost pressure you should really have one fitted
Interesting, does this apply to diesels too? I still only have 14psi tho so I guess that still counts as low 🙂
Nearly all diesels have no need for a dump valve as they don't use a throttle butterfly.
Infact not all petrol engines 'need' them. Currently running over 40psi boost with no dump valve with good results on a car I'm playing with.
Harmitans is right, D's rarely need one.
I'm interested in seeing his 40psi engine though, genuinely! However its not really for the sake of the engine is it, its for the turbo and its bearings, shafts and related pipework.
skidartist - excellent- made my day!
[url= http://www.barryboys.co.uk/phpBB2/viewtopic.php?t=30869 ]
[/url]Give me a choice between a convicted Paedo and a self-righteous, arrogant, lycra-wearing pedallist for a neighbour, I'd have to get back to you. Seriously.
Haha. Angry bods on the internet are funny.
Those were the days, my old Montego Turbo, bigger turbo, huge intercooler, carb off a model engine to bleed air from the waste gate to control boot pressure!! It was 150bhp as standard but used to give std. Cosworths a shock!! Most fun I've had with my clothes on!!
Oh yes, it did have a dump valve, not to increase power but to prevent turbo stall as previously mentioned, it had a carb, not fuel injection, so as soon as you take your foot off the throttle the butterfly closes and the boost pressure has nowhere to go - que the dump valve, turbo keeps spinning and less lag in the next gear simple.
Obviously open to abuse because the driver can decide where to back off the throttle!!
Coffeeking, don't have any pics of the current turbo here. A lot has changed but the pic below will give you a rough idea.
This was the old turbo, which ran similar pipe work, but including a dump valve that is no longer used, flat foot shifting has negated the need.
Throttle body in the pic split which gave a good reason to go to a bigger turbo and more fuel. There is enough capacity on the fuel system to reach 50psi in the near future. Although it is already making approx 900HP at the wheels!
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This turbo in conjunction with 5 others produced 70psi boost. Whistles like **** when they get going, although the spool is a little slow. Again no dump valve, but it is a Diesel!
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Thats a nice looking bit of kit, I suspect not exactly road-friendly behaviour though 🙂 Cant work out from the surrounds of the bay what the car is. Some serious cash gone into that! Flatshifting would negate the dump valve requirement I suppose, yup!
...can i be carspotter and guess its an M5? I can't imagine how you could get 900 horsies out of anything smaller!
Its a very short engine, and only 4 cyl by the looks of it?
Not quite. It's a Mazda 13B rotary in an RX-2 chassis.
[i]Anyone knowing the original 6r4 knows it was undeniably a beast, if a little unreliable. Shame group B was banned.[/i]
I remember going to the pre-rally show for the Jim Clark Rally in Duns and thinking to myself 'what a £$%^' when I looked in my mirror at a guy turning up in a '6r4' behind me...
When I had another look at it later on, I realised it was actually a real one! 😀
It's my joint favourite Gp B car, alongside the Ford RS200.
Shame [url= http://www.rallybuzz.com/lancia-ecv-group-s/ ]Group S[/url] Never saw the light of day, competitively...
Wow, wasnt expecting a ****el!
Wow, wasnt expecting a ****el!
Me neither - what does 40 (or 50) psi do for the rotor tip wear?
Don't all the VAG diesel engines have a dump valve? And the 1.9 and 2.0 VAG engines must be the most common engines on the road..... My Audi certainly goes 'Tiss'.
Aracer - 40psi seems to accelerate wear slightly. Although fancy apex seals (ie horrendously expensive) have improved this on the new engine.
Samuri - Not sure about the VAG dump valve to be honest. Road going diesels are not my strong point, and have advanced so much in recent years that it could well be possible.
RudeBoy with Maria Callas at 5kW, I'd be more worried about your sexuality than class 😀
I'd also worry about how long the car would stay glazed when she hits the really high notes!
Samuri - Not sure, I've just had a browse of some VAG literature and couldnt see any reference to one as standard, and found a forum where they were clammering for a diagram of how to retrofit one (with a bunch of the regulars pointing out that anyone knowing anything about TDs will laugh at them if they hear it). 🙂 That said the 3 litre TD in our landcruiser has a throttle plate controlled by cable, just as a petrol does. Its apparently for emissions, it helps draw the EGR gasses into the intake more and a few other things I dont follow on a D etc.
yeah, I had a look around after I'd posted, couldn't find anything definitive.
It's not a WRX Tiss, quite a quiet and subtle Tiss and you've got to be skinning it to make it do it.
