Dump valve open
Turbo Mini Forums

feebs
that is a worrying post

The inlet is either Vacum or positive pressure

Vacum, will make the dump valve open
+ presssure will make it close

so the idea being, flat out gear ( all that nice +'ve pressure in the inlet keeping the DV closed ) , change gear ( this will instantly create vacum again in the inlet ) the dv will open ... Ptoooosh , back on the gas and the DV closes once again


If your DV is opening at 3000 odd revs while you still have your foot planted to the floor on the accelartor ... then there is something seriously wtong ... when it opens in this scenario, what does your boost gauge read ???? assuming the DV and the boost gauge are at the same place your DV will not open while +ve pressure is showing on the boost gaugue

S

TurboLessTosser

could explain the dodgy runnin habits....

yeah Iain it sounds bizzare dosnt it ...
like its dumping everything when its supposed to be giving everything !!
only the throttle butterfly closing could get -'ve back in the inlet ...
lets find out where the DV is getting its feed from
I cant wait ......... ... ..

Edited by b12 on 12th Jul, 2004.

TurboLessTosser

something isnt right. Then again it could just be the noise but i doubt it at only 3k. I know when i didnt have much between me and the engine there was a lot of "whoosing" noise (for want of a better word!) that was with no dash and nothing filling the centre "spit" hole.

Are you sure it is the dump valve making the noise? If there are any pipes lose or there is a hole somwhere then as boost is made it will start wooshing. i.e leaking. If it is only a small leak then i guess you are not making enough boost just reving it to make any wooshing noises.

Just a thought.

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A man without a project is like a like a woman without a shopping list.

jimmy, it sounds like that might be the MBC you can hear at 3000rpm, as you have it set so low. just a thought...

Dan

Dont know, but when i took the feed from the T piece idea of daves, everything works fine!

Previous Engine: 1040cc Morespeed engine, 1275 turbo head T2 Turbo Mirage Manifolds Megajolt
Previous engine: STD metro turbo, megajolt
Drives: 399bananahp (flywheel) Honda Civic Vtec b18c4 T28 Turbo 1968 Mini

Megajolt maps to download: http://www.jamesfawcett.co.uk/cms/index.ph...&gid=3&Itemid=3

It wont make it lean because the extra air is before the carb.... it just means you get a bit of un filtered air