Dump valve on a supercharger??
Turbo Mini Forums

Just a question really. Why would you need a dump valve on a supercharger? Thought it was to release pressure at the turbo to stop it stalling? Remember to be nice as im a car spaz on lunch and found someone selling a kit with one supplied.
http://cgi.ebay.co.uk/HONDA-S2000-COMPTECH...A1%7C240%3A1318


Thanks gang

Edited by johnnysti on 2nd Feb, 2009.

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Well on my G-lader charger it just vented to atmosphere, but that was a g-lader not a binny one? not sure on any other?

"Cars are a lifetime of pain"

Im running a 45 in mine at the mo that i got from Vmax and never fitted one and was never advised to. While i was looking around on egay i stumbled accross the above and he was selling one on there. I became confused, with ease!!!

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That's a thought actually. Say you are travelling along at 5000rpm then you let off, the SC is still be pumping lots of air with nowhere to go. The turbo in this case will slow, and a dump valve will help if fitted.

Fastest 998 mini in the world? 13.05 1/4 mile 106mph

I recon you can use one, just how you fit it will be the nightmare part. Cause as wil_h says it need's to escape if your sitting at 5k rpm when you let off. Remember on turbo they have the plenum's whereas you don't so how you fit it would be interesting.

http://photobucket.com/quintonrose

Absolutely no need if you are using a suck through setup.

With suck through and say you let off at 5k, the supercharger pulls a vacuum against the carb and the engine pulls an even lesser vacuum against the supercharger. The blower is still delivering a flow of air, but at very low density.

If you are using a blow through setup, then you need a dump valve or even better a recirc valve.

Saul Bellow - "A great deal of intelligence can be invested in ignorance when the need for illusion is deep."
Stephen Hawking - "The greatest enemy of knowledge is not ignorance, it is the illusion of knowledge."

The Honda set up is blow-through, a belt driven turbo really, but the Vmax setup is such-through... If you were to fit a dump on this, wouldn't it spray a mix of hot air an petrol into the engine compartment... Me no like!!

come on guys get your brain in gear!

im putting one on the fiesta, you need one with blow through setup or it will just pop the hoses off (or break something id imagine!!)

what im not so sure on is if a single 1" one will be big enough and if i should hook it up to vacume or just use it on the spring as an over pressure vent.

Im thinking using it on the spring alone will help with throttle response as you will allways have a nice lump of high pressure in there to fill up the plenum when you open the throttle again.

Yes i moved to the darkside

Instagram @jdm_brett

my charger is going to be a blow through. Im not after the dump valve sound just the fact that if it helps everything happen better and preserves the engine/charger then its worth it is my thinking

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If you use suck-through, a blowoff valve will not work and has No Use! This is because there will never be any boost pressure behind a closed throttle butterfly, this is because the carb is 'sucked through'..

If you blow through, throttle response will be improved and a blow off valve will Need to be fitted to prevent the possibility of butterfly being damaged on lift off, then jamming open on next throttle application.
However, assuming you will be using a lobed blower, eg. bmw mini rootes style, you will not benefit from enhanced between-rotor sealing which occurs when atomised fuel passes through a supercharger. This is what all V8 drag cars do.. They have thousands of horsepowers'.

thats a vortech style supercharger, i.e. its a turbo compressor wheel, i.e. itll suffer surge jsut like a normal turbo compressor wheel, i.e. a dump valve is needed to combat the surge, jsut like with a normal turbo. it is in no way comparible to a displacement type supercharger aside from the fact it makes boost.

and if you have a suck through setup with a carb, dont ever ever even entertain the thought of fitting a dump valve. seriously, think about it for a second. the carb makes a nice flamable air fuel mix, which is then agitated by the charger, which your then going to spray all over the engine bay??? see the problem?

boom.

Edited by evolotion on 2nd Feb, 2009.

turbo 16v k-series 11.9@118.9 :)

Denis O'Brien.

I must have missed the centrifugal bit, appologies.. (didnt click on the link)
So he should treat is as a normal turbo setup, intercooler, metro plenum,carb,manifold..
That is a cool kit but a higher pressure rad cap is a poor excuse for dealing with higher coolant temp! And that chargecooler rad should be bigger! Defo.
Looks very like the centrifugal charger'd pink S2000 in 2fast 2furious driven by that Fit oriental lass..

Ha! Whatever man I'm down with that funky shit..

haha

Venting to exhaust! It would sound sweet on the over run lol!

1/4 Mile 14.3secs 96Mph Terminal 10psi of boost.


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