delayed dump?
Turbo Mini Forums

hey chaps, im currently using a forge dump valve think its a group A, connected to the side of the plenum chamber.
but instead of getting the sudden release in pressure when i lift off the throttle, its slightly delayed and quite a long ssssssshhhhhhhhh! if ya know what i mean.
initially i thought it may have been my throttle cable being quite short, slowing the butterfly valve. i have now changed this and it is still the same.
ive checked the diaphram and that is fine and bought a new spring.
would a higher rated spring solve this?
oh and im only running at 4 PSI
any help would be great.
cheers

'always keep a spare shot for a stray bird'

Have you still got the overrun poppet valve in the carb butterfly?

Hi,
Where's the vacuum line connected too?
Cheers,
Gavin :)

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sounds like oil contamination of the DV maybe

the carb is just standard so i prosume it has tom. the vac is taken off the inlet manifold.
ive checked the diaphram and is fine no oil just a smell of petrol.

'always keep a spare shot for a stray bird'

Hi,
That'll be the problem then, get yourself a plain throttle disc.
Cheers,
Gavin :)

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Edited by Brett on 24th May, 2007.

Yes i moved to the darkside

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I would be carefull if brazing it as the disc is only small alot of heat may cause it to distort and impare the fit in the carb throat.
Shane.

forget the throttle disc blanking thats not the problem

i run with one in ..(ie)... standard carb

and i sometimes run over 20 psi of boost

the problem here is weedy boost 4psi

it will do that, mind you if you want to stick to 4psi

the the disc applies!
7psi would sort the problem and be more fun!

also would not strain things too much

Edited by BENROSS on 25th May, 2007.

if you have a piston dump valve then it sounds like the dump valve fitting is at fault.

if you've fitted a piston dump valve and the vacuum pipe is vertical and out the top you will have this problem all the time. turn it upside down with the vac pipe at the bottom and never have this problem again.

Delayed Dump?

have you tried syrup of figs or Ex-Lax??

Sorry mate couldnt resist.

Im not sure whats causing it, if you want pop round some time and try my valve on yours.

Medusa + injection = too much torque for the dyno ..https://youtu.be/qg5o0_tJxYM

Start by changing the butterfly - or sodlering up the holes.
This has been covered before a few times.

cheers for all the comments chaps. i will be running around 10 psi, but dont want to turn it up yet till i get everything sorted i.e I/C setup and megajolt on.

'always keep a spare shot for a stray bird'

http://www.Zeemax.com

butterfly is in the carb, there is a thingy me bob in it with a spring extra, otherwise known as the poppet valve, pull it to bits and plug the hole or get a plain disc as found in NA 44's i believe.

Edited by Zeemax Power on 27th May, 2007.

http://www.Zeemax.com

Zeemax ... nobody is going to be able to tell you what needle you'll need as every engine is different.

Stick the std BDD in, back the boost right off and run the motor in that way (obviously make an attempt to get the mixture somewhere near ... if ever so slightly rich ... normally get close enough with a colour tune).

Once the engine is run in get it booked into the rollers.

Get them to do the first run or two on the low boost setting just to make sure that everything is working as it should then wnd the boost up to the max level you will run and do the power tune.
Finally if your not going to run at your max boost get them to do a couple of runs with the boost turned down so as determine that the fueling and ignition settings remain safe (they should).

Any guestimation with fueling on a forced induction engine usually results in broken everything!!!!!

Every day is a school day ...........

How fast and how expensive ...... the same question...

Cheers for the help rodger wasnt really after people telling me what neadle to have more interested on what other people are running and what results they were getting? I take it by this your running the standard neadle? I thought i'd put an up rated one in cause i'm going to have it tuned the chap at avonbar reckoned it would be a good idea? Thanks for the advice anyone any thoughts on the return plate upside down i think thats what Turbo shed means.

http://www.Zeemax.com

Zeemax ... I honestly can not remember what needle I was running in my last turbo motor and since it was sold about 4 years ago I can't really check!

I know that Jimster ran a standard needle in a monster motor!!! Also know several people with mild motors running really high fueling needles ... it's an odd game this tuning business.

Every day is a school day ...........

How fast and how expensive ...... the same question...

cheers i feel confused now

http://www.Zeemax.com