Twin Dump Valves

[Jamo]

I know a couple of members are running twin dump valves. Has anybody got any close up pics of the setup / pipework?

[kwlw]

I know a couple of members are running twin dump valves. Has anybody got any close up pics of the setup / pipework?

At least one has - with the most beautiful 80q ever built. Even pics of two stages (I assume that was not the best idea locat bov's near TBV).

Development:



Then he got rid of the MAF (moved to pressurized side?)

Final version:


Sau

[Jamo]

Thanks hmm not going to be easy but gives me nice ideas!

[Keeper of The Kitten]

What's the reason for / idea behind running two BOVs / DVs instead of one?

__MDC__

[Ross]

I'm hazarding a guess that this to eliminate the risks of turbo-stall when you're running high boost pressures? I suspect if you can't get rid of all that air quick enough, it'll push back against the compressor turbine which is an issue. Two DV's helps 'dump' the excess on lift-off before this occurs.

Anyone got a 'real' answer?

Ross

[BrianSmith_S2]

I'm hazarding a guess that this to eliminate the risks of turbo-stall when you're running high boost pressures? I suspect if you can't get rid of all that air quick enough, it'll push back against the compressor turbine which is an issue. Two DV's helps 'dump' the excess on lift-off before this occurs.

Anyone got a 'real' answer?

Ross

But he seems to be running with two pairs of std dump valves (4 in total ) see last two pics.


Brian

[Graham]

The last pic has them plumbed in before the pressure system though on the suction side of the compressor

[Jamo]

I'm hazarding a guess that this to eliminate the risks of turbo-stall when you're running high boost pressures? I suspect if you can't get rid of all that air quick enough, it'll push back against the compressor turbine which is an issue. Two DV's helps 'dump' the excess on lift-off before this occurs.

Anyone got a 'real' answer?

Ross

Correct it also goes back through the MAF.

Hence why power boys go for 50mm BOV to remove more air

[jogi730]

I once asked my tuner why people sometimes fit 2 dump valves. He replied because the first one they fitted would not be big enough. Please don't shoot me down in flames if there is more to it than that, but looking at it simplistically, it makes perfect sense.
Cheers
Chris

[LHD_Kid]

The big power Jap stuff doesn't necessarily use 2 valves,
I will try and get some pics...

[Jamo]

I once asked my tuner why people sometimes fit 2 dump valves. He replied because the first one they fitted would not be big enough. Please don't shoot me down in flames if there is more to it than that, but looking at it simplistically, it makes perfect sense.
Cheers
Chris

I aint seen a bigger recirc does he know of one?. I've seen big BOV / dump valves which dump to atmosphere though.

[jogi730]

Ah.... did not realise you meant recirculating - it just said dump valves. What size are you using? I will be in touch with him on Monday so will ask.
Cheers
Chris

[jogi730]

I aint seen a bigger recirc does he know of one?. I've seen big BOV / dump valves which dump to atmosphere though.

Sorry Jamo, taken longer to get hold of tuner than I thought.
Biggest recirculating dump valve is about 5" (125mm) and is from a company called Sadev?
Hope this helps?
Cheers
Chris

[Jamo]

Well you learn something new every day! thanks Jogi