[Jersey335xi617]

Im currently running catless turbo back, intake, and Cobb. Will my stock divereter valve hold all the pressure of the cobb or should i get a BOV? Also someone told me these cars are meant to have the DV and dont do a BOV.

[Jeff@TopGearSolutions]

Originally Posted by Jersey335xi617

Im currently running catless turbo back, intake, and Cobb. Will my stock divereter valve hold all the pressure of the cobb or should i get a BOV? Also someone told me these cars are meant to have the DV and dont do a BOV.

Every car is different, especially mileage on the hardware. Only a pressure test of your system can determine if your DV are leaking and can hold the excess boost or not. There is no harm in using a BOV on this car. A leakly system would cause wastegate duty cylces to increase, putting more wear and heat on the turbo's, reducing efficiency and increasing wear over-time.

You have many options for upgrades including a Forge DV upgrade with the use of your stock charge pipe

OR

You can upgrade your charge pipe and use a Forge DV or other BOV like Tial HKS or Synapse.

Any questions you can PM me or check out our site.

[benzy89]

Assuming you're running Stage 2 on the COBB (since the only requirements are upgraded intake & DPs), I ran into the same issue. I called COBB & asked if there's anything else I should worry about/consider upgrading. They said on Stage 2, some people have experienced leaks on their OEM DVs & that I should consider looking for Forge DVs or something comparable to ensure that I don't have any boost leaks (in the end, I decided to also replace the CP to make sure nothing leaks/cracks on my DD running higher boost).

DVs vs. BOVs

• If you go with Forge DVs, you can still use your OEM charge pipe and its just a simple swap with the OEM DVs.
• If you decide to go with BOVs, you'll need to pick a specific BOV you want to go with and then buy a new CP (ER, Stett, ETS & AA). If you're planning on running meth, it makes sense buying a new CP w/ meth bungs so this "negative" cancels itself out.

IMO, BOVs are annoying (constant wooosh noise when it vents pressure) and are a bit cheesy, not for a BMW (not trying to make my car a Fast & Furious set piece).

To each's own, personally I like the DV set up since that was what BMW used from the factory & I like my "silent sleeper" set up.

[E90SoFlo]

I have forge DVs because I don't like the woosh sound. It's all personal preference either works just done

[oshusttoley]

Originally Posted by E90SoFlo

I have forge DVs because I don't like the woosh sound. It's all personal preference either works just done

with your dv's, do you hear more of the woosh then on the stock? i know they both very quite but i know my stock one you can sill faintly hear it

[335xi Kevo]

Also note that BOV's run rich as it is venting metered air. A negative effect of BOV's.

[Jeff@TopGearSolutions]

Originally Posted by 335xi Kevo

Also note that BOV's run rich as it is venting metered air. A negative effect of BOV's.

What do you mean? I havn't seen anything like that on this platform. I know on the Subaru platform people had those issues but they were on a MAF based system, but they just needed to tune for it. I believe that is only a myth for untuned vehicles or ones on MAF. We are MAP.

[benzy89]

Originally Posted by Jeff@topgearsolutions

What do you mean? I havn't seen anything like that on this platform. I know on the Subaru platform people had those issues but they were on a MAF based system, but they just needed to tune for it. I believe that is only a myth for untuned vehicles or ones on MAF. We are MAP.

+1, this was the 1st I've ever heard of this problem. All things I know that are "bad" about using BOVs is that you lose a negligible, insignificant amount of meth when it releases pressure.

[Proper Motion LLC]

U can get some "BOV"s and not get the "whoosh" sound. Just vent the air back to the intake tube like stock.. I know u can do that with the Synapse BOV.

Also u can get the whoosh sound from DV's as well, just vent the DV to the atmosphere.. U can even do that with stock DV's..

[old account 2]

Originally Posted by Jersey335xi617

Im currently running catless turbo back, intake, and Cobb. Will my stock divereter valve hold all the pressure of the cobb or should i get a BOV? Also someone told me these cars are meant to have the DV and dont do a BOV.

In my experience, the stock DV's work just fine for your application. In some instances, changing to upgraded DV's has led to surging and even underboosting. I would save the time and money and stick with the stock ones.

[Chipedy]

In my experience, the stock DV's work just fine for your application. In some instances, changing to upgraded DV's has led to surging and even underboosting. I would save the time and money and stick with the stock ones.[/QUOTE]

How?

[benzy89]

Originally Posted by Chipedy

In my experience, the stock DV's work just fine for your application. In some instances, changing to upgraded DV's has led to surging and even underboosting. I would save the time and money and stick with the stock ones.

How?

The Forge DVs have 4 different springs. Sometimes people put the wrong springs in and the DVs either unintentionally hold or dump pressure. The 4 spring types are:

• Green 5-15 PSI
• Yellow 15-23 PSI
• Blue 20-23 PSI
• Red 30+ PSI

Don't ask me why there is an overlap in the Yellow & Blue springs or why there is a 7 PSI gap between the Blue + Red springs. On OEM turbos most people use yellow., if you have RB turbos Blue might work best.

[335xi Kevo]

Originally Posted by Jeff@topgearsolutions

What do you mean? I havn't seen anything like that on this platform. I know on the Subaru platform people had those issues but they were on a MAF based system, but they just needed to tune for it. I believe that is only a myth for untuned vehicles or ones on MAF. We are MAP.

If this were true then the 2.0 fsi motors @ VW wouldn't experience this however they do, direct inject on a map based system.

The thing is ur venting off metered air. The ecu has to compensate.

[Fundahl]

Originally Posted by 335xi Kevo

If this were true then the 2.0 fsi motors @ VW wouldn't experience this however they do, direct inject on a map based system.

The thing is ur venting off metered air. The ecu has to compensate.

You are not venting off metered air in a MAP based system. It reads manifold absolute pressure and temperature, not the actual air volume through a metering device like what you are thinking. It will almost instantly adapt to the change in pressure.

Some cars have a MAP and MAF sensor.

[Jeff@TopGearSolutions]

Originally Posted by 335xi Kevo

If this were true then the 2.0 fsi motors @ VW wouldn't experience this however they do, direct inject on a map based system.

The thing is ur venting off metered air. The ecu has to compensate.

To be quite honest this is the first I've heard of anyone bring up BOV problems and running rich on this platform. Please bring some evidence to the table to support your theory with this platform.

I've been running BOV on this car for 3 years seamlessly with no problems in controlling AFR and neither have the 100's of my customers.

I think you are confusing other platforms and their problems;this is not a real problem on this platform. This ECU and system is completely different from the VW's.

[old account 2]

How?

The springs haven't seemed to be an issue, but we have had problems with a couple aftermarket DV's actually leaking.

[benzy89]

Originally Posted by Thomas@GIAC

The springs haven't seemed to be an issue, but we have had problems with a couple aftermarket DV's actually leaking.

Forge's? Cause don't they have a lifetime guarantee?

[old account 2]

Originally Posted by benzy89

Forge's? Cause don't they have a lifetime guarantee?

I hesitate to name a specific company, as I would rather keep this as a discussion. What I will say is that we have had multiple customers experience underboost issues with aftermarket DV's. They switched back to the stock ones to remedy the situation.

Since we are still early in our aftermarket turbo development, I cannot yet speak for the high levels of boost that will be seen in such builds. But for everything up to our Stage 2 Race, running 16-17 PSI, we have seen no problems with the stock DV's.

And like you mentioned, some people use springs that are too stiff. If this happens, and excess pressure is not diverted upon throttle closure, you have a whole different problem on your hands.

For what it's worth, if it were me I would save the money and keep the factory DV's on a stock turbo setup.

[MDORPHN]

Originally Posted by Thomas@GIAC

I hesitate to name a specific company, as I would rather keep this as a discussion. What I will say is that we have had multiple customers experience underboost issues with aftermarket DV's. They switched back to the stock ones to remedy the situation.

Since we are still early in our aftermarket turbo development, I cannot yet speak for the high levels of boost that will be seen in such builds. But for everything up to our Stage 2 Race, running 16-17 PSI, we have seen no problems with the stock DV's.

And like you mentioned, some people use springs that are too stiff. If this happens, and excess pressure is not diverted upon throttle closure, you have a whole different problem on your hands.

For what it's worth, if it were me I would save the money and keep the factory DV's on a stock turbo setup.

And what would you recommend for those running higher levels of boost?

Neil

[old account 2]

Originally Posted by MDORPHN

And what would you recommend for those running higher levels of boost?

Neil

Neil,

We are still testing the ceiling of the stock DV's. Since we haven't had a failure at this point, I really cannot recommend against them. For what it's worth, Evolution Racewerks is running their DV charge pipe with a Tial BOV on the GIAC Stage 2 Race 135i. They have not had any problems with this setup, even when pushing our beta file to 18 psi.

[benzy89]

Originally Posted by MDORPHN

And what would you recommend for those running higher levels of boost?

Neil

If it means anything to you, Shiv is using Tial on the single-turbo kits

[Mike@N54Tuning.com]

Originally Posted by Jeff@topgearsolutions

To be quite honest this is the first I've heard of anyone bring up BOV problems and running rich on this platform. Please bring some evidence to the table to support your theory with this platform.

I've been running BOV on this car for 3 years seamlessly with no problems in controlling AFR and neither have the 100's of my customers.

I think you are confusing other platforms and their problems;this is not a real problem on this platform. This ECU and system is completely different from the VW's.

Jeff is spot on. There are no issues with BOVs on this platform.

Basically it boils down to personal preference. Get a BOV if you like the sound. There are quiet BOVs like TIAL and then there are louder ones like Synapse and HKS. Its all a matter of preference.

If you stick to stock DVs or Forge DVs then they operate pretty much silently.

Mike