[E90who]

I know it doesn't really matter, but just want some of your guys' advice/opinions.

My set up is a 335is with DCI, OCC, ETS CP, HKS bov, generally running map 1 on jb4.

I've tried both, I would just like to be educated.

[Miller335]

I'm ok with diverter valves.

If you run the BMS cowl filters the DV's are plenty loud in the cabin if that's what you like.

[E90who]

Originally Posted by Miller335

I'm ok with diverter valves.

If you run the BMS cowl filters the DV's are plenty loud in the cabin if that's what you like.

Don't I not use my diverter valves because I have a bov?

[Miller335]

Sorry I mis-read.

I thought you were implying DV's vs. BOV, apologizes.

[Transport3r]

It really doesn't matter. Recirculating the charge air is only necessary in MAF (Flow sensor before the turbo) cars, like the Audi/VW's etc. MAP (Pressure & Temperature sensor after turbo) cars like ours don't care if the charge air gets vented to atmosphere or not.

Do whatever you like! If you think the noise is neat, VTA. If you think it's too loud, recirc!

[E90who]

Originally Posted by Transport3r

It really doesn't matter. Recirculating the charge air is only necessary in MAF (Flow sensor before the turbo) cars, like the Audi/VW's etc. MAP (Pressure & Temperature sensor after turbo) cars like ours don't care if the charge air gets vented to atmosphere or not.

Do whatever you like! If you think the noise is neat, VTA. If you think it's too loud, recirc!

Is my butt Dyno wrong in telling me that I have a little better throttle response when recirculated?

[Transport3r]

Originally Posted by AlecSinger

Is my butt Dyno wrong in telling me that I have a little better throttle response when recirculated?

Throttle response will vary, but it also depends on how fast the valve snaps shut when the manifold goes under vacuum. For example, my synapse valve improved the throttle response a lot over my stock DV's despite being VTA, because it's a really quick valve. It will only affect the response post shift though.

Where do you recirculate to? one of the stock DV ports?

[Jklad]

Before deciding to my dv's or bov, I asked one of the popular tuners on here who said you want a dv so that the air recirculates. Can't exactly remember the reasons he cited though.

Edit: just noticed you were only considering bov, I'm guessing the same idea about recirculating could apply ...

[SINGH_]

Originally Posted by Transport3r

It really doesn't matter. Recirculating the charge air is only necessary in MAF (Flow sensor before the turbo) cars, like the Audi/VW's etc. MAP (Pressure & Temperature sensor after turbo) cars like ours don't care if the charge air gets vented to atmosphere or not.

Do whatever you like! If you think the noise is neat, VTA. If you think it's too loud, recirc!

[blaster3500]

I have my synapse recirculated. It was way to loud for my taste and I do not like the chance of unfiltered air getting in. People claim it is always blowing but there are times where it seems like it is pushing air and other times it is not.

[E90who]

Originally Posted by Transport3r

Throttle response will vary, but it also depends on how fast the valve snaps shut when the manifold goes under vacuum. For example, my synapse valve improved the throttle response a lot over my stock DV's despite being VTA, because it's a really quick valve. It will only affect the response post shift though.

Where do you recirculate to? one of the stock DV ports?

From the bov to the throttle body.....hope that's not bad.

[blaster3500]

It needs to recirculate pre turbo. If you are recirculating by the throttle body you are pretty much looping the bov/DV and not letting off any boost

[E90who]

Originally Posted by blaster3500

It needs to recirculate pre turbo. If you are recirculating by the throttle body you are pretty much looping the bov/DV and not letting off any boost

How would I do that?

[Dan_335]

By having the hose from your BOV going to somewhere between the intake and the turbo?

Like what the stock diverter valves do.

From the turbo>>intercooler>>throttle body is a pressurized system under boost. If you are recirculating back into this section of the system, the air isn't going anywhere and you aren't relieving pressure from the system.

What you will actually cause is air blow back through the turbo blades.. ie flutter noise. Sounds cool, not the best way to do it. Might as well have no BOV at all if you are doing this.

[Transport3r]

Originally Posted by blaster3500

People claim it is always blowing but there are times where it seems like it is pushing air and other times it is not.

I agree, our engines pull more vacuum than a typical turbo 4, I've caught mine uncomfortably close to no flow while open, so I slapped a 3" K&N filter on it. Muffled the noise a bit too. Where do you recirc it to?

[shadow191]

Unless the spring is messed up or there's a leak, it shouldn't draw air in. Never had any issues on any turbo car over the years with venting. Right now only downside with the BMW cowl filter is that some fumes get into cabin from the vented air. Not a big deal.

[3000GT MR]

Ideally you want to recirculate. It's less suction the turbo has to do, quicker spool, air has already cooled, and more. You will have more performance out of recirculating over atmosphere.

[ndq]

I've ran the stock diverter valves and then switched to a ER charge pipe with Tial Q BOV (installed yesterday). Runs more or less the same.

It's all up to you and your sound preference. Been running vent-to-atmosphere BOVs for years on many turbo-equipped vehicles and never had any issues due to using them. And they sound kinda cool...but ricey. I chose the Tial Q because it's really not loud at all.

[E90who]

Originally Posted by 3000GT MR

Ideally you want to recirculate. It's less suction the turbo has to do, quicker spool, air has already cooled, and more. You will have more performance out of recirculating over atmosphere.

So where do I recirculate to exactly lol.

[blaster3500]

There is no bolt on solution for recirculating a blow off valve. I loved my recirculated diverters but it left no room for any intake other than dci's. I switched to a synapse and made a custom mr5 style intake. In the tube there is a 1 1/4 bung. It takes some fab work but turned out to be good clean solution. I imagine you could recirculate into one of the stock ports and leave the other capped but I wanted it discharging evenly into both banks

Synapse solution:





Diverters

[3000GT MR]

Originally Posted by AlecSinger

So where do I recirculate to exactly lol.

The factory system is already recirculating, just use stock style valves. I'm not sure on what brands or who carries, Forge maybe? I'm sure others could help in that department

[Sandman614]

Originally Posted by 3000GT MR

The factory system is already recirculating, just use stock style valves. I'm not sure on what brands or who carries, Forge maybe? I'm sure others could help in that department

ECS has OEM and Forge DV's