Hi all, I was browsing through the tinterweb 'tother day, and stumbled across a thread talking about the benefits of running without a dump valve, basically saying it's smoother....

haven't a clue if this is the case, has/does anyone on here run without one, and can give an opinion....

probably covered before, apologies if thats the case....

If you call turbo stall smoother?

Complete rubbish..

I thought so......cheers!

There have been many many many many arguments debates on the subject of running without a dumpvalve.

The only "improvement" I have heard about is the pidgeon noise if you like that kind of thing

Otherwise as the knowledgeable Sam says, it creates turbo stall, which I can't possibly see making anything smoother.

Some interesting reading on it here from Guy Croft, basically his opinion is that running with no dump valve risks creating turbo lag and damaging the turbo itself.

Having said that, last time I advised on running a dump valve on this forum I got some stiff disagreement so there's certainly those who think differently...

Personally I agree with Guy Croft and Fiat that a dump valve should be used.

Gareth

My experience concurs with Guy Croft's findings on lag...

The turbo spins at upwards of 100,000rpm so it is not stalling as the boost is running back through it, although I'm sure it does slow it down though. This would explain the slight jerky-ness I experience betwen gear changes. It is definitely not smoother than with a DV installed.

I've been running with no DV for about 20k and my standard turbo is fine (and on 115k). Since my OE one was broken I removed it and never got round to replacing it. Can't really comment on the lag, it may be worse than with a DV, however without a DV my turbo is on full boost by 2,500rpm. If you were slow upshifting from WOT to WOT the turbo would need to recover the speed lost, that said it does do it rather quickly as you tend to drop back into high revs if you are going for it.

It is on my to do list of things to do but I've just not got around to it, other things keep coming up!

Not been running one on my 16vt for all the time I've had it and it's been totally fine and on the stock turbo on 115k and not a breath of smoke or oil anywhere! (touches wood)

Dump valves, in my opinion sound chavtastic, (apart from the HKS jobbies) and create just as much lag as running without one.

As Vas says here - http://www.fiatcoupeclub.org/forum/ubbthreads.php?ubb=showflat&Main=37959&Number=470320#Post470320

"did around 150K km in four years without a DV (both pipes blocked) turbo is still fine, no play, no smoke, worked flawlessly.
Surge sound is so

I think it's one of these urban myths tbh..."

It sounds great, drives fine and is up to you whether you fancy running without one or not.

There will always be stories of people running with no dump valve and having no problems whatsoever, the same as there are stories of people running decat on a standard turbo with no problems alongside stories of people killing their standard turbo within a week of decatting.

In my view what's important is that people are informed of the risks (from forums like these) so they can make an informed choice and take the risk if they choose. What's scary is people (not on this forum) swearing blind there will never be any problems with running no dump valve and pretending manufacturers just fit them for fun...

Gareth

In theory, the action of turbo stall should lead to shaft play and, eventually, it does BUT the life of a turbo without a dump valve is not *that* much shorter than that of one with.

You'd be surprised how quickly a turbo spins down when the revs are off, even from full chat so stalling it isn't quite as bad as you'd imagine.

By keeping the boost pressure in the system, lag is reduced. A BOV will vent that pressure, increasing lag and sometimes causing fuelling issues. A re-circulating dump valve should both keep the turbo spinning and help retain some of the boost pressure but it's still not ideal.

That's my view anyway, afterall, when's the last time you heard a turbocharged car in motorsport use a dump valve - it doesn't happen.

By Jingo, I'd never thought about it really!
But listen to that chatter!

And I must admit I've been through lots of videos of rallying and can only hear pidgeon chatter.
But then motorsport turbos probably get rebuilt quite alot anyway

Yeah when cars are driven like on that video I think blue smoke on startup after 120k miles is the least of their worries

Never ran a DV for over two years on T34 No problems DV's are shiny things for kids and magpies IMO.

I'm pretty certain that manufacturers fit recirc valves primarily for noise suppression.

I've read up a huge number of threads on different forums (because I'm sad and get obsessed with car stuff) and you'll never find anyone who says "I ran without a DV and my turbo blew up." It just doesn't happen.



Now if you were running THIS at 30 psi, MAYBE you might wanna think about a recirc valve...

i have a whoosh type on mine and hate it would rather have a recirc or maybe none but if it is not needed why would the manufacturer fit it?

Why would someone who calls themselves lewoosh, hate the woosh sound

Recirculating all day long, ticks the most boxes. Best performance choice and no silly noise.

Yep if you're old and boring which I can imagine you must be lol!

rally cars CANT use them as they run anti lag,doesnt work.and dump valves were fitted by manufacturers as a noise suppression device as normal people running turbo cars would repeatedly bring cars back to dealers complaining of a strange noise.
and as for the performance related issue,ive never started blowing up a baloon,then if i need another breath leave the air to escape again before i blow again.i always pinch the bottom of the baloon between breaths,makes it a bit quicker.

THIS is chatter: http://www.youtube.com/watch?v=hEK7POxpVeE

...and also the best combination of sounds ever

Haha I like what you said there GS_Racing and so true lol!

Oh and Nedge the Group B Quattro is PORN and makes the perfect sound!!!

Mid thirties, is that old? sometimes feels it.

I could definately bore you on the engine fitted to your car as you don't like to listen I can tell.

Oh I like to listen to the noises my car makes you see. Mid thirties, well that's 10 years on me. Perhaps I'll want it quieter then?

[quote=DidCoop) Perhaps I'll want it quieter then? [/quote]

If you value performance over sounds by then you'll have proper engine noise and won't need the silly pishswishstallshxt.

the benefits of introducing heated air into the inlet of a turbo must be staggering.please do not belittle his choice on the grounds of performance,you would be hard pressed to see real life results.

lmao i called myself lewoosh when i was all excited about getting another turbo car but had a woosh one on my r5 and always wanted a recirc but already had a decent woosh one on so till i sort everything else out its last on the list but i do love the explaination of the balloon and yes why would you let air out each time you take a breath ha ha best explaination ever SO if i take mine off what sorta noise do i get i love the rally car sound how doi get it

And Lewoosh you have just shown a good example of a young guy with a turbocharged car. Oh dear oh dear oh dear.

The only reason mine is blocked off is due to the fact my Bosch device doesn't like 1.3 bar. I'll get a HKS SSQV when I can afford 1.

GS you're totally right about results. Perhaps when I get my HKS device I'll put it on the rollers before and after so we can see what performance different (if any) it makes.

As you say the brief moment of heated air being put back into the inlet to be diluted by the fresh incoming would take a bit of seeing in real life were it not for the fact that it's a higher mass than atmo being fed straight back in. Response can only benifit. If the recycling bothers you vent to atmo and live with the noise, I hate it. To not provide a vent of any kind is what makes no sense at all, that can only stall the compressor which makes it job harder. When you blow your balloon you pause to take breath, since when does a turbo stop spinning and pause for breath? wishpishstall

touche lol agreed turbo does not stop i will wait till i can afford a decent recirc untill then im happy to be a chav lmao

Chavtastic!

You ALL Wrong!!!!!

You should go out and get one of these

http://cgi.ebay.co.uk/Saber-EDV-V3-Fake-...=item23073b113c