Volvo Turbo Blowoff Q's
 

yea so i got a TD05-12B from a 740 DL, its got the blowoff on the compressor housing, is anyone familiar with this? i was just wondering if anyone knew what this sounded like, and would it affect anything if the top of it is a little crushed??? ill post pics if anyone wants to help me out with this/knows what the ---- im talking about. thanks.

Re: Volvo Turbo Blowoff Q's
 

yeah. post pics

Re: Volvo Turbo Blowoff Q's
 

Attachment 37999
https://img.photobucket.com/albums/v622/d16crx/bov1.jpg


the first one shows the bov on the compressor housing, the second one shows where it got crushed a lil bit, does anyone know if this will make a diffrenece.?

Re: Volvo Turbo Blowoff Q's
 

i had that same turbo.... take that bov off and completly fill it in with jb weld to keep that bitch shut... u dont want that on there trust me. even with vac it opens under boost... jus keep it shut and jb weld the ---- out of it and run a differnt bov on ur piping somewhere.... TRUST ME =x

Re: Volvo Turbo Blowoff Q's
 

thanks.. but i kinda used up my budget on other ----.. so ill have to use that one till i get money for a real bov. do you think theres gonna be any issues wit it being a lil crushed.?

Re: Volvo Turbo Blowoff Q's
 

Looks like the exact same diaphragm cap that comes on the 1G DSM, which is a great junkyard BOV. I was holding one up to the picture on the screen, identical in proportion.

The small dent doesn't look like anything from what I can see. People actually slip the DSM units into a vise and crush the whole top (dsm.org has writeups) to increase the spring tension of the BOV for higher boost apps.

I suspect turboDA6 had a defective unit, or poor vacuum supply to the BOV. If the spring tension of the unit is low, as per a 6 psi *automatic* turbo car, I can see where it would get blown open if you had a few psi pressure drop in the charge pipe. At that point, crushing it should take care of that problem... O0

Re: Volvo Turbo Blowoff Q's
 

yea the turbo is mitsu made for the volvo 740dl for 3 years... so what your saying sounds good. thanks.

Re: Volvo Turbo Blowoff Q's
 

yea o saw one of those at a local yard. I was gonna take it just to sell it. BOV/Turbo combination... I'm sure it works fine... just shitty if one or the other components break...

Re: Volvo Turbo Blowoff Q's
 

to where does the air/pressure escape????

Re: Volvo Turbo Blowoff Q's
 

it escapes back towards the turbo inlet. self recirculating... im telling u i tried using that bov. its designed kinda like the 1g bov but its spring is so soft it can't hold boost for ---- =x that piece of ---- would open under boost then flutter when i let off like it was clapping open/close open/close... if u dont listen u will regret how ur boost feels. u get 4-6 psi tops then it opens. n stays open acting like a hole in ur ic piping. feels gay n sounds worse.

Re: Volvo Turbo Blowoff Q's
 

i dont have the same turbo, but the same BOV system.

mine is an td04-16t
from a volvo 850 R-->5 cil with 250 bhp..

isnt it possible that it can handle a little more psi?? :-\

Re: Volvo Turbo Blowoff Q's
 

I have one of these 12b turbos sitting on my shelf. I would like to install it on a bike in the future. I'd like to see if I can mod the bov like this:

http://www.thedodgegarage.com/turbo_bov_mod.html

I'm not a big fan of crushing them. I think blocking off the boost source from the compressor housing to the bov shouldn't be too challenging. Just have to see if venting the bottom side of the diaphragm to atmosphere is feasable.

D16y8 I see you have an adapter plate on yours. How did you seal the turbine against the plate with that recess in the flange?

Re: Volvo Turbo Blowoff Q's
 

You're so uninformed. Blow off valves and bypass valves are always open during vacuum. The only time that either closes is when you reach + boost pressure 0<psi. The reason you hear the audible sounds is because your throttle plates close (shifting) and you go under vacuum long enough for the valve to open and boost pressure to escape.

Blow off valves while working the same as bypass valves, also have the ability to be adjusted. This allows for less opening/venting at idle (hard setting) which increases spring tension and the valve needs more vacuum to open. On the soft setting, you'll notice that you can blow off at idle. This is nothing but the lowest amount that the spring needs to open the diaphragm and allow minimal boost pressure to escape with maximum noise.

Notice that if you have yours adjusted at it's "hard" setting that it won't blow off at idle and your boost will feel more consistant, this is because you're not losing boost pressure from a weak setting.

As far as the DSM bypass, it needs 17 inHg to even START opening and isn't fully open until 25 inHg.

If you were getting flutter, it's because your engine wasn't creating enough vacuum to open the valve effectively in the first place, not because it was leaking under boost. It might have opened some, but not enough, which is why you heard flutter.

Re: Volvo Turbo Blowoff Q's
 

Fluttering can also be caused by a structurally weak vacume line, colapsing under vacume and not allowing the bov to function properly.

Re: Volvo Turbo Blowoff Q's
 

Beside the point that it doesn't even start opening untill 17 inHg and isn't fully open untill 25 inHg:

http://img133.echo.cx/img133/5109/dsc023856nc.jpg

http://img133.echo.cx/img133/6055/dsc023868up.jpg

http://img133.echo.cx/img133/5465/dsc023879xo.jpg

http://img133.echo.cx/img133/7541/dsc023888sl.jpg

http://img92.echo.cx/img92/2834/dsc023890dr.jpg

http://img92.echo.cx/img92/6537/dsc023907gp.jpg

As for an understanding of how a bypass or blow off valve works:
http://img23.echo.cx/img23/8033/bpvprinciple3nr.jpg

And here is a movie for you as well:
http://jholland.phpwebhosting.com/si...urbo%20007.MOV