Volvo 850 reculation valve help

bigty69 · Post by **bigty69** » 05 Oct 2016, 15:55

Ok so i am in the process of putting a recirculation valve on my 1997 850 t5. I was just wondering where the best place to put the outlet for the discharged air in the intake pipe before the mass airflow sensor or after. I know the maf on these vehicles are picky and i have heard on other cars guy doing it after the sensor but im not sure. So if anyone could chime in and let me know that would be great! Also yes by doing this i am deleting my cbv.

Post by **tryingbe** » 05 Oct 2016, 19:05

Your car already have one stock, there is zero advantage, not even for the noise since you won't be able to hear it.

beigg · Post by **beigg** » 05 Oct 2016, 19:30

before is where you want it.

Sommerfeldt · Post by **Sommerfeldt** » 06 Oct 2016, 05:24

beigg wrote:before is where you want it.

Are you sure? Wouldn't that meter already metered air again?

- S

beigg · Post by **beigg** » 06 Oct 2016, 07:03

Sommerfeldt wrote:
beigg wrote:before is where you want it.
Are you sure? Wouldn't that meter already metered air again?

- S

That is how it was meant to be understood.

I believe we both understand the intent of what to do with the air, but the wording is catching us up here creating confusion.

You do not want to recharge the already spent air.

bigty69 · Post by **bigty69** » 06 Oct 2016, 10:27

The reason im doing it is cause im running a manual boost controller and already getting flutter from the stock cbv. With a bigger turbo injectors and some custom tuning i am hoping to see around 300 hp. The factory cbv has been known to fail under high boost conditions i dont see a problem replacing it with a better quality one made to hold more pressure. it will be doing the same job as the factory one just more suited for my application. So plumb it before the maf?

Sommerfeldt · Post by **Sommerfeldt** » 06 Oct 2016, 15:01

beigg wrote:
Sommerfeldt wrote:
beigg wrote:before is where you want it.
Are you sure? Wouldn't that meter already metered air again?

- S
That is how it was meant to be understood.

I believe we both understand the intent of what to do with the air, but the wording is catching us up here creating confusion.

You do not want to recharge the already spent air.

No, before the MAF would be between air filter and MAF. After the MAF would be between turbo and MAF. In this system, wouldn't discharging the air before MAF metering make for inconsistencies? I'd think that plumbing it in after the MAF, i.e. between MAF and turbo, like the line on the TCV, would be the way to go?

- S

bigty69 · Post by **bigty69** » 06 Oct 2016, 17:59

I just thought you would want the maf to register the air that is going into it so it can account for it and make any changes. Where does the factory cbv dump the air?

beigg · Post by **beigg** » 06 Oct 2016, 19:29

It's already registered once and being recirc'd for use again.
Before/pre/charged pipe side is preferred if I were doing it.

Post by **erikv11** » 06 Oct 2016, 20:11

LOL hard to get a straight answer sometimes, OP?

The factory CBV discharges into the intake manifold.

So basically "after." After the MAF, after the snorkel pipe, after everything but the intake valves.

The air is metered by the MAF, then charged/boosted, but because the boost is too high some air is dumped off the turbo instead of into the intercooler. Wouldn't make sense to boost that dumped air again (though you could I suppose), boost is already too high, so just send it along to the end of the whole intake system: to the intake manifold.