martin800

hi there. i am thinking of removing my dump valve completely to give my car that lovely wrc chatter. just wondering if it is just a case of blanking off the hole left in the tmic and the pipes. have read that a TD05 can cope with this but is a TD04 just as safe. any help would be very welcome. cheers

scoobyDAZZA

yep , you are correct , make sure you get the blanking plugs/bungs air tight though , i got mine on flea bay , 25 or 34mm IIRC , £8 delivered

i did it on a vf34 which is not as strong as the td series

funkyspider

Wont it just cause back pressure on the turbine and stall the turbo, taking longer to spin up again ?

Genuine question.

scoobyDAZZA

not sure TBH but that would explain why it makes the chatter noise

martin800

to quote someone more in the know than myself,


It doesn't change the spool up point of the turbo. Lag is NOT the RPM at which the turbo spools up, Lag is a time measurement of how long the turbo takes to spin up. When you change gear you let all the pressurise air between the turbo and the manifold out, and you have to wait for the turbo to make all that back up again. With no dump valve you will maintain some pressure, such that it's there when you put your foot back on the throttle.

jaytc2003

iTrader: (1)

but with the air still pressurised between the turbo and the intake, this will then stall the turbine so when you open the throttle again you may have a bit of pressurised air there (but the pressure will have dropped lots as the turbine has stopped pushing it) so you have to wait for the turbine to spin up again, whereas with a dump valve, the turbine does begin to stall but at a much slower rate so when you re apply the throttle it is quicker to spool up again to give positive boost.

silent running

Exactly so. If you want a compressor stall sound (a twittering/fluttering noise) then just fit a big open induction kit. Then you'll hear it a lot clearer. The dump valve serves a purpose on a road car, extending the life of the turbo and allowing it to keep spinning between gearchanges. Take the dump valve out and every time you let off the throttle you're punishing the compressor wheel. Rally cars have anti-lag and also don't have to worry about service life either.

But by all means try it and see what you think. You'll find you may not like the way it drives without a dump valve. I tested this out very cheaply - bunged up the vacuum hose with a bolt, joined the dump valve inlet and outlet together with a short length of solid wooden broom handle that I cut down LOL it was just the right diameter! No need for pricey alloy bungs off ebay.

Tuts

And what did you find after you disabled it Silent?
How did it run?

scooby-tc

iTrader: (2)

Ive been running without a dv for over 6 months now and the car drives better than it did with the std recirc on (well on my car it does) all cars are different so some people might experience differences

Bob Rawle

If its a maf based car then you could find it becomes very jerky on shift and lift off.

bob

martin800

thanks for all your feedback. think i will try it and see how it goes, out of curiosity more than anything else.

scooby_rock

can i just ask what version impreza your runing and what turbo as im thinkin of doin th same ,,,,cheers

silent running

Well I was trying to rule it out as the cause of an idling problem I had. All I know is it was awful to drive without the dump valve. The urge through the gears was just gone, felt really laggy. That was a MY98 WRX running a VF35 turbo.

scooby-tc

iTrader: (2)

Im running an MY98 STi Type R with a TD05/06 20G turbo

black_scooby

Hi Bob,
I have exactly that and its making the car a nightmare to drive, i was told to leave the dump valve off when i fitted a FMIC, trouble is i fitted a HKS dump valve that i have and it was still the same, do you have any ideas for me to try to stop this happening, its a MY93 by the way.

Cheers Lee

black_scooby

Can anyone help at all with this one??

scooby-tc

iTrader: (2)

Sounds like you have an air leak somewhere a split hose or something.I would check the hose between the wastegate and the bit it attaches to under the manifold and also where you have blocked the hoses.You might just need to tighten a jubilee or something

black_scooby

Will do Cheers

Nich B

Is your BOV adjustable? either through increasing / decreasing through a wind in screw the pressure it takes to blow, in other words if its too high it will feel like like taking it off all together and not having a BOV, or by changing the springs

I have this problem of jerkiness when lifting off the throttle

VF35, Forge rc dv,

it looks like the spring is too strong and needs changing, am awaiting the postman as I write, so maybe new year now

Happy Xmas

black_scooby

I think its adjustable, its a HKS SSQ, when i fitted it the car drove exactly the same as with no dump valve, hopefully if i can reduce the tension it will work.

Cheers

Multijfj

I actually did what your suggesting on my rover 220 turbo, and that chattered, and after a while, jesus christ its so annoying. But anyway, thats beside the point -

I bought a dumpvalve from scoobyclinic, the GFB Stealth, which is fully adjustable sound wise, and whether its a re-circ or atmospheric, when you adjust it to fully one way, cant remeber which - but it chatters as if there is no dumpvalve, and then when ur bored u can adjust the sound etc. its the winner!

scooby-tc

iTrader: (2)

you should have got the dumpvalve from Motobuild for your rover 220,i had one on my coupe and i thought it sounded great I was young though

black_scooby

Ok, Could not find any obvious air leaks and i've tried to adjust the tension on the dump valve spring, unfortunately it's still the same, anyone got anymore suggestions please.

Lee

scooby-tc

iTrader: (2)

remove the dumpvalve altogeter and plug the hoses and see how it drives even if only to eliminate the dv afterall it could be that thats knackered

Nich B

Are you able to change the spring for a weaker one? I know Forge do other springs not sure about yours though?

black_scooby

If you read the thread i'm running without a dump valve and am trying to solve a problem based on that.

Cheers anyway

black_scooby

All of the experience on here and no one can help???

marklemac

all you've said is that you have a MY93 car and a FMIC and no DV.

Whats the EXACT spec of you car ?

Then perhaps you may get more help.

scoobyDAZZA

who's thread is it ?

maybe you should start a new one

black_scooby

Sorry your right
MY93
FMIC
440's
uprated fuel pump
full de-cat
lateral clutch and lightened flywheel
PFC only running about 1.2 bar
thats all i can think of at the moment

This only started when i fitted the FMIC, and yes i apologize i should have started my own thread, but when i read this it was also relevant to me and i thought it might have some bearing on the guys original question.