Be Excellent To Each Other

I've been meaning to find this out for ages, and was just reminded to ask...

I just walked past a Subaru of some variety which made a "whoosing" sound, not dissimilar to the sort of noise made by an air brake on big lorry, as it accelerated away. One of the cars in Burnout 2 also made this noise, when changing gear - but what causes it? I suspect the turbo, but don't they normally whine rather than whoosh?

Almost certainly the car has what the boy-racers call a "dump-valve" installed.

Edit - beaten to it

Another mystery solved, thanks to Beex!

Do I have one of these?

If not, why not, and where can I get one?

You don't have a throttle plate so you don't need a dump valve.

I want both of these things.

You want a bypass system, they're a far bit better.
You also want an anti-lag system.

But if you do get an anti-lag system, be prepared for people looking at you like you're even more of a giant cock than the guys who go around dumping their boost pressure through the dump valves.

Anti-lags sound like Onslow's car backfiring from Keeping Up Appearances.

I want to change the dump valve in my car, and get an anti-lag system

Anti lag.

http://www.youtube.com/watch?v=xygZQKOG ... r_embedded

Sadly I know the cunt. (in the car, not filming it).

EDIT. But I probably wouldn't call him one to his face as he's about the same dimensions as the actual John Coffey.

Okey dokey, another question:

To Supercharge or to Turbo?

I found this http://www.superchargersonline.com/content.asp?ID=19 "discussion" that comes down in favour of the supercharger, but which is really better? Also, can you have both?

Interesting use of the phrase "actual John Coffey"

Yes you can have both

Yes. Yes, you can.

http://en.wikipedia.org/wiki/Twincharger

I thought you cannot have both because they feed into the air induction ?. odd.

There are two different types of SC I am aware of. Centrifugal and roots. BMWs use roots (or that's what they choose to use).

From what I can remember turbos deliver more power at once and SC deliver it later higher in the rev range. There is no such thing as free power though and turbos suffer with lag (from waiting for the pressure for the back impellor to CFM into the induction) and SC are connected to your drive belts or different if roots (iirc) so you are putting strain on the engine.

That's roughly what I remember from it all. Several of my friends (here and USA) are experts on the matter but tbh I just let them do all the work whilst nodding my head going "uh huh" as they got into all the techy bits of it. So anything above could be the wrong way around or just completely wrong.

Hmm, yes I think that's correct (about the rev range) as they are mechanically driven and not by waste gases from the exhaust.

You could have all these things, or you could be secure in your masculinity.

The MkIV Toyota Supra uses twin turbos, but in sequential mode rather than parallel like most twin turbocharged cars.

This basically means that you all but eliminate turbo-lag as the first turbo spools up at low revs and there's already enough waste gas flying about to spool up the second turbocharger before it kicks in.

It's not even exotic. There are Golfs with this. Apparently it enables them to put puny 1.4 litre engines into the cars that are fuel efficient without making the car slow.

Only problem is the Supra's curb weight.

1,550 kg isn't that heavy for the type of car (a grand tourer). The Ferrari California is just under 100kg heavier I think.

The real problem that the Supra has is that it's just not capable of putting power down to the road very well.

Kinda like my pal's 900 brake Skyline Mind you, he has the option of 4wd.



He broke down the running costs the other day. Absolutely insane.

Here's his older one doing a rolling road. Just over 700. Problem was (as he explained) that to go from 700-900 you're into tens of thousands. So he sold this one (didn't like the kit or chameleon paint) and got the white one at around 800.

Aye, but you get flames coming from the exhaust

The problem with a mechanical supercharger is that it runs all the time and wastes energy. A Turbo can actually improve efficiency (recycling waste heat as it does), and is used for that application on big diesels.

An electric supercharger might be a good idea for small cars. It could be cheaper than either a turbo or supercharger, and would have no loss when not in use.

When you hit the switch it would pull 2 or 3kW from the battery to spin the compressor up to provide near-instant boost, enough for occasional fast acceleration.

I think the Rotrex centrifugal supercharger has a clutch that works somehow. They can be doubled up, too.

Edit: Though now I have a quick look, I can't find that, so maybe my memory is being faulty again.

Of course you can put a clutch on it (see Mad Max's Interceptor!) but it's starting to get a bit overkill on a Citroen Saxo or whatever.

Although...



(supercharged reliant 850 engine)

I've heard talk of "the valley of death" on some of these twin-turboed Jap cars when reaching the end of one turbo but before the other turbo spins up. Hence people fit turbo timers to bring sequential turbos in together.

I was looking at imported Subarus I think when I came across this. Ever heard of this?

I've not heard of that being an issue with the MkIV Supra. Don't know about Subarus, didn't even think they had any twin-turbo motors.

The Mazda RX-7 didn't suffer from it either, unless the plumbing was going bad. Which (apparently) it does. Quite a lot.

Yeah some of the imports, Legacys I think, have twin turbos. Perhaps it's just a Subaru problem.

When you see an exploded diagram of the plumbing inside the RX-7's engine bay, you begin to understand why

I read a long time ago on another forum far, far away that you can get a dump-valve sound kit that you can fit to any car - so you can push a button in the car to get the PSSSSSSSSSSSHHT sound. I think it may have just been a speaker that you fit under the car somewhere.

From the descriptions I read, it sounded hilariously shit, especially when people were setting it off when waiting at traffic lights

Can I get one for my electric car?

Bzzzzzzap!

If you could get one with the sound the Jetson's space cars made that'd be acebest.

So, is this the new car thread, or should we merge it in with the behemoth?

Interesting reading

http://www.boosthead.com/home.php

Thomas Knight leccy SC.

Aha! Well, there you go.

Boosh head, more like

What's that sound that goes 'Eeeeerp Eep! Eep! Aaaaaaaaaaaaaaaaaarb bruh bruh bruuuuh braaaaaaaaarp mmmmmmmph' when I close the boot?

The person you beat half to death?

(Am I doing this right?)

No, it's about XXchargers.

It's about mysterious noises.

*poot*

*schpleeeeeeeeeemsch*

Seeing as you like to make stuff and can weld I figured I would upload this for you. My friend paid $10 for it when we were bored one day.

We never did play with it (we can't weld) but in theory the principle seemed good IIRC. Any way, enjoy !

Fuck all the whooshing and slurping. My favourite sound is wastegate flutter.

A shart?

Yes !