Dump Valves

[Pixel]

Hey guys,

If you didnt already know, I have a Peugeot 206 HDi 2.0 D-Turbo, you should know this as my signature makes it painfully obvious. I want dump valves for my car, they are very common on diesels with turbos right? I want the sound anyway and my mate said it could cost me £350 in total whilst a different mate said it would cost £50 or less.

I just want that sexual hissing sound between gear shifting.

Can you help me out?

Pixel.

[HDi fun]

You can get a kit that makes dump valve noises via under bonnet speakers for fifty quid.

I never thought that a dump valve was applicable to a diesel engine. Diesels run on excess air (no throttle to restrict air intake, like a petrol car has) so no need for a dump valve.

When you lift off the pedal in your (diesel) car all you're doing is telling the ECU to stop fuelling. Air flow is never changed, so your turbocharger will spin up equally quickly in the next gear. There's no need to 'dump' an air charge as it's always available given the nature of a diesel engine.

PS:- HDi Peugeot diesel units sound pretty nice anyway, they hiss and make air intake noises under acceleration that are quite sexy (if cars' noises can be as such)

Dump valves have a use in off-road petrol fuelled rally cars. To me they sound like someone trying to flush a toilet inorder to dispose of an unrequited turd and an over size sanitary towel. Not so sexy, really.

And, with a diesel turbo, no need for it.

[oceaness]

Might look a little silly with the big HDI badge on the back when your car starts sounding like a petrol

[HDi fun]

There is that. Badges can be removed though. And diesels still sound like diesels outside when they're sitting still (with the engine running, obviously).

[vr1066]

What is the actual purpose of the of a dump valve(s), is there more than one.

Yes thats right, the newbie siren just went of for that question

[HDi fun]

Dump valves allow the turbo(s) to carry on spinning in free air when the throttle is closed during gear changes. It helps to eliminate turbo lag. If you're a race driver you probably won't need 'em as you'll keep the throttle pedal flat down (against the rev limiter) during changes anyway.

Clearly this is more economical if your sponsor is paying for your tyres, clutches, and fuel.

Dump valves don't really have a place on the road with sophisticated engine management systems.

But they do make a good sound if you like that sort of thing.

[vr1066]

Thanks for the answer.

Can I assume that you wouldn't fit them if your not running a turbo or do ppl just use them for the sound?

I think I'm more interested in the engine noise than the dump valve. Although I'm curious about them as I've heard them mentioned a few times.

[HDi fun]

Dump valves had a place in Group N Rally cars back in the late 1980's. As for road use; technology has moved on. Engine management systems take up the slack, a good re-map can make all the difference.

Yes, they do have a purpose, but no so much as they did a few years back.

Dump valves belong in 1984 Fiat Uno Turbo's.

[Pixel]

But the sound is sexy

[HDi fun]

You can't use a dump valve on a car without a turbo - there's no point.

You can get a kit that has under bonnet speakers to make dump valve noises.

But it sounds so silly when you're going up from 3rd to 4th at 35 mph.

You'll never hear them on a race car as the engine's doing 8000+ RPM when changes are made so it gets obliterated.

Still, if you really want to, why not?

Cheers,

P.

[Pixel]

I dont want speakers...

Cant I get proper dump valves for my turbo that make a proper noise?

[HDi fun]

I'm not sure you can with a diesel.

The reason is that a diesel engine doesn't have a throttle valve as such, in terms of airflow restriction. Diesel engines are controlled only by the amount of fuel metered and subsequently injected, and the amount of air that the turbo is shoving in. Clearly all this under ECU control in your car, as it is in mine.

Don't you think that the almost ultrasonic hiss of the turbocharger compensates? A sympathetic ECU remap will make it sound much nicer. And it will go beautifully, too.

Sadly, none of these will recreate the authentic sound of a proper mechanical dump valve.

I think you'll find that they're getting scarcer even in petrol turbo track racing cars as the ECU's now control so much of the engine that the function can be taken over electronically by artificially 'damping' the throttle valve and wastegate.

I'll do some more research. If you want to get a true Peugeot specialist's opinion then please do contact Matt Jobling of Pug1Off Limited on 01280 701919. He's the only man to know when it comes to performance Citroens and Pugs.

He's done some really impressive conversions. For example: installing two 3.0 V6's in a 306. You may have seen it in Max Power magazine.

Regards,

Paul Anderson.

[Pixel]

My brother has a 306, 2.0 HDi with a Dump-Valve.

So it CAN be done...

[HDi fun]

OK, educate me please. I genuinely didn't think it was possible with an excess air engine.

Does it help performance?

[Pixel]

I really dont think so, as you said, dump valves are best suited for old petrol engines.

I think its all just for the lush sound.

The only problem is, Im sure it will get very annoying after a while.

[HDi fun]

THat's a fair point. After a while you might get fed up with it. Can always take it off I suppose.

[Pixel]

If only it was as simple as a button.

[HDi fun]

It's as simple as not bothering. HDi's sound nice anyway, especially if you get it re-mapped to wind up the boost pressure low down. Even the 90bhp will go to over 120 and sound like a rally car at low revs.

[Pixel]

Yeah my one is 90bhp and it can be remapped to roughly 125.

I doubt I will bother with dump valves.

[HDi fun]

Go for the remap. It's money well spent.

Trust me, you'll like the immediacy of the pedal when it;'s done.

Celtic Tuning did mine - given my car is 139bhp in factory tune the 192 they got is stunning. No need to use it all though - changing up at 2500rpm still leaves you well ahead of 16v two litre Golf Gti's etc. The torque in the midrange is absolutely silly. The car will fidget if you over pedal it in third (in the wet fourth can be interesting!).

What you get though is the delight in driving a car that pulls in all gears evenly. No peaks, no troughs, just loads and loads of torque. No dump valve will ever achieve that.

[aswearing]

well, you're convincing me diesel is better..........

[HDi fun]

Diesel is a very worthy compromise now.

Better than petrol? Well, that depends on how you define better.

Litre for litre a high tech turbo-diesel engine is going to outrun a petrol engine of the same size with consumate ease. That's before we modify either of 'em. Diesels are also very quiet now with all the added (costly) technology such as dual mass flywheels, hydraulic engine mounts etc.

My 2.2 HDi with a remap has the sort of mid revs mid speed range shove that you'd expect from a 3.5 litre petrol engine. Surely the 3.5 will win in the end as it can be revved to 7000rpm plus. In gear though, not much in it.

Whether you make any monetary savings is debatable. Diesels do need more frequent servicing; the filters are more numerous and more costly; the engine oils have to be fully synthetic etc. road tax is levied above a petrol car.

I'd stick with the 206, consider a good custom re-map, run it on BP ultimate diesel and dose up with Millers Diesel Sport additive.

Watch you mates' Saxos and 106's disappear gracefully in the mirror.

[aswearing]

i dont have a 206 hehe

[HDi fun]

Originally Posted by aswearing

i dont have a 206 hehe

Nor do I

[Pixel]

He was talking to me, lol.

What oil do you recommend HDI?