morto

can some one tell me the differance between a Manual Boost Controller and a bleed valve?
cus i thought they were the same thing??

thanks
andy

jaiscossie

Same thing just sounds a bit better i guess even though there not !!

morto

just found this from a post off here

a bleed valve does what the name surgests, it bleeds a set (set by a screw) amount of boost away from the accutrator. Whilst a MBC (dawes device) masks all of the boost until a set point (set by up again) usinf a ball and spring arrangment. Google dawes device, should show you

the dawes is the same as a boost controller

jameswrx

Ball and spring controllers are not the same as bleed valves. Bleed valves are rubbish. Ball and spring actually work very well, dawes device is good (but costly) I've used one like the r-spec ones on my old evo 5 and it was great, awesome for spool and didn't spike, held good too.

scoooby slayer

iTrader: (4)

they are awesome. got an apexi avcr boost controller on my skyline.
you can set a spike of boost for the big punch then tail it of however you want.
basically with a controller you have BOOST CONTROL.
with a bleed valve you have a little knob to make the boost go up and down a bit like the flintstones had on there car lol

fordpop

So if you turn a knob up or down are you not controlling the boost? Is that not boost control? How can you set spike and tail off with a manual boost controller over a bleed valve? Electronic boost controller yes, manual controller NO!

scoooby slayer

iTrader: (4)

dont quote half my quote you half wit !

thats exactly what ive said in the part you didnt quote about my apexi avcr, surely even you realise its an electronic controller ! lol

RSargie

on the subject, has anyone treid one of thease yet?
http://cgi.ebay.co.uk/Manual-Boost-C...item518da6b3dd

they are ball and spring type, like a dawes i belive, price looks good as well.
it says it dosent bleed, so no loss of metered air and just opens at set pressure?

scoooby slayer

iTrader: (4)

they are fine if you want to just set a boost pressure at a certain level and leave it.
if you want a varying boost curve proper controller or mapped air injectors are needed.
my cos had 22 psi to 4700 rpm, 25 psi to 6300 rpm then 32 psi to 7800 rpm so as to prevent surge issues. air injectors were set in the map by msd.

GTi-R23

I used a dawes type valve on my Punto GT, worked well if you want to set a boost limit and leave it there.

stevos

Manual boost controllers and bleed valves are sh*t your better off paynig for and electronic controller such as scoobyslayers apexi as you can set them up with various amounts of boost and you just switch between them to suit your stlye of driving at that point.( you wanna go quick switch it to a higher boost, if your just driving normal have it at standard settings) all in all a better system

scoooby slayer

iTrader: (4)

they are awesome mate

mine was set up yesterday to 1.7 bar spike, 1.5 bar held tailing to 1.4 at the limiter due to injectors getting to the limit.
with a bleed valve or manual would of been 1.4 bar and thats it or £660 for new injectors

stevos

Its a much more sensible way of controlling boost as you say you can control your spike where as the manuals just spike like f**k had both on my pulsar and the manual used to spike around 4-5 psi, did't stay on long until i bought a blitz spec r for it as it was only £200. better that than rebuilding an engine due to a s**t £20 maunal one

fordpop

I don't use them so I don't know what they are you pratt, people that use bleed valves are morons, and boost controllers are for to55ers that can't drive without the boost being reduced for bad road conditions............... Which one are you?

Rsmat

iTrader: (2)

no need for that mate!

scoooby slayer

iTrader: (4)

you sir are an absolute tit ! do you have any understanding of a turbo engine ? when pushing the boudries of a turbo charged engine with a big turbo they can create surge as the turbo is so big the boost has to be held back as the engine cannot consume it in lower revs.

my skyline gets on the limit of fuel at around 580 bhp so boost has to be held back slightly to keep inj duty at 90 %.

why are you commenting on something you clearly know nothing about ?

Chris69

I had a bleed valve then switched to a cheap manual boost controller- the difference is like night and day- the manual boost controller hardly spiked at all and held the psi much better.
big difference in the way they operate- you wann make sure its the ball and spring type not the simple screw in and out bleed valve.
I think a few of you missed the point aswell- he was asking about
A MANUAL boost controller vs A bleed valve not a relatively expensive electronic unit.

Ad4m RST

Boost controller is always a tarty part of the spec so people are bound to chirp up with expensive electronic ones...gives people incredibly passive access to the cars map so always good for performance involvement. Shame it makes a tuner of everyone... lol


I'd use anything over a bleed valve, had a 'dawes' manual valve on a ZVH running a nice surgey T34 and held brilliantly, only 12-13psi to be fair.