To blow off valve or not, that is the question?

Hi Guys,

I am currently running my 1.8t BAM on Emerald K6 with a forge 007P with yellow spring and I quite like the idea of a Baileys dual piston dump valve (DV26) which is for the Audi S3 225BHP according to the Baileys website.

I am not running a MAF and dont really like the idea of running hot air back into the cold side of turbo, sounds counter productive considering you can get a cold side kit but thats alot of money compared to just have a dump valve to air, so....

Is anyone running this dump valve and does the sound get bloody annoying, do you lose any performance benefits?

 

I'd stick with your 007P tbh, it only dumps for a spit second and still goes through the I/C but its also closer to the turbine blades. I can't see a cold side giving any power benifits and the money could be put to better use.
My DV is loud,drives me mad sometimes.

 

Cheers Tommy, food for thought. I might test a second hand unit out.

I am still interested if anyone vents to atmosphere?

 

I have a Blitz SSQV that vents to atmos pre I/C

My plan is to vent post airbox to quiet down the system as you would in an OEM application.
Venting pre intercooler is actually adventageous to reponse as your charge temps are hotter and the intercooler has not done any work on it yet.

 

I have a dv26 and recently gave it a clean and re grease. Now it dumps for a shorter time and doesn't leak boost. Like anything the noise is ok for a while but ideally i'd like it a bit quieter.

 

Cheers Toyotec that gives me an idea on the placement of the dump valve as I will put this in the current location. The Blitz SSQV on youtube sounds loud?

Cheers Russ, I also looked at the DV36 which is meant to be lower sound compared to the DV26.

Do you have any vids of the sound?

 

I dont sorry. If you were at the cgti dyno day you could hear it for yourself.

 

Damn oh well, I think I will give it a try and see how it goes.

 

Hey Russ, have you had any fuelling issues with your dump valve?

 

You should have no fuelling concerns with a dump valve, if the fuel algorithm is speed density as in Russ' and mine.

In Emerald's ECUs this means looking at "map compensation" and offsetting the pecentage -ve for a back out.

 

As mentioned. No fuelling issues. Only hesitancy due to a sticking valve leaking on low boost.

 

Kool, well I have just won on eBay for cheap cheap money lol so I will pop it on and see how it goes.

 

I thought a picture paints a thousand words, this is the map compensation snapshot.

 

It is.
The screenshoot however, is the MAP compensation when in positive air pressure (boost). On a back out you can get to -0.80 bar or 20kPa.

 

Thanks for getting back to me.

I thought I would put up the negative boost settings as well

 

Well I fitted the Baileys DV26 and it runs fine on low boost pressure but once you get to say 15 psi plus I start to loose boost. I think its possibly a spring issue or vacuum. I might try my mates Forge Twin Piston Dumpvalve BOV with a stiffer spring.

What I must say compared to the Forge 007P is that the forge is louder by far and more aggressive. The throttle response is also a lot better with the forge fitted but off throttle or feathered throttle the Baileys seems smoother.

 

Does anyone have a green spring for the 007P I could borrow and test please?

 

Well I got a 008 for the cost of a 007P I sold.

I am wondering does the spring really matter as I am running 23psi on full chat, according to forge this should be a yellow spring.

When you fit the DV the inlet on the DV fits against the pressure so why not just use the standard green spring?

I am really trying to understand why bother with an uprated spring?

 

008 is defo louder that then 007 with an open cone filter for sure. I am currently running the green spring and to be honest I cannot see the difference.

 

Well I changed the spring over to a yellow and I can say that difference is massive. Throttle response is sharper, boost holds better in high rpm but.....at low revs is not so nice.