Using external wastegate

[TWC]

My recently installed lower mount turbo set up uses a garrett gtx turbo and an external wastegate/dump tube. All I well with that and the car runs great

Anyways, my question is - why am I not hearing any off throttle compressor surge? There’s no bov of course,as that’s not an easy task on these cars and I know my factory method of letting off boost through the exhaust shouldn’t be functioning anymore due to the removal of the ewg. I’m currently running 24 psi which is relatively low for this turbo. What exactly is happening to my off throttle surge since it doesn’t seem to be getting chopped up in the turbo?

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[Bflood]

Not sure why you don't hear surging... maybe boost is too low to hear it? Everyone I've talked to says these cars don't need a BOV however nobody has given a good reason why. The simple fact is BOV's are benefiting the turbo and not the car so you should in fact need one if you want your turbo to last.

There are a couple different kits out there but personally I'd go this route.
https://bigboostturbo.com/collectio...b58-blow-off-valve-kit?variant=35478953132183

 

[Guff]

My recently installed lower mount turbo set up uses a garrett gtx turbo and an external wastegate/dump tube. All I well with that and the car runs great

Anyways, my question is - why am I not hearing any off throttle compressor surge? There’s no bov of course,as that’s not an easy task on these cars and I know my factory method of letting off boost through the exhaust shouldn’t be functioning anymore due to the removal of the ewg. I’m currently running 24 psi which is relatively low for this turbo. What exactly is happening to my off throttle surge since it doesn’t seem to be getting chopped up in the turbo?

I have no experience in this so my answer is completely a guess, but I was under impression that the boost venting through the exhaust was entirely handled by the VANOS system. It uses a combination of cylinder shutoff and valve timing overlap in order to vent the intake through the exhaust valves.

The wastegate just handles boost control at the exhaust side, but a BOV/BPV, or in this case the VANOS system, vents the pressure that already exists in your intake side.

Presumably, you still have the VANOS system active in the same way, hence why it's still venting and not surging.

 

[TWC]

I have no experience in this so my answer is completely a guess, but I was under impression that the boost venting through the exhaust was entirely handled by the VANOS system. It uses a combination of cylinder shutoff and valve timing overlap in order to vent the intake through the exhaust valves.

The wastegate just handles boost control at the exhaust side, but a BOV/BPV, or in this case the VANOS system, vents the pressure that already exists in your intake side.

Presumably, you still have the VANOS system active in the same way, hence why it's still venting and not surging.

Interesting, I didn’t know vanos controlled it. I mean, that would explain no surge happening. Setting up a bov system would be a complete waste of money if my car is still relieving boost like factory.

 

[TWC]

Not sure why you don't hear surging... maybe boost is too low to hear it? Everyone I've talked to says these cars don't need a BOV however nobody has given a good reason why. The simple fact is BOV's are benefiting the turbo and not the car so you should in fact need one if you want your turbo to last.

There are a couple different kits out there but personally I'd go this route.
https://bigboostturbo.com/collectio...b58-blow-off-valve-kit?variant=35478953132183

We don’t have a vacuum source for Bob’s which is why nobody uses them. I have big boosts turbo kit on the car, they were supposed to send me the bov set up but that’s another story, however the owner told me it’s not even necessary.

 

[Maffyou]

I have no experience in this so my answer is completely a guess, but I was under impression that the boost venting through the exhaust was entirely handled by the VANOS system. It uses a combination of cylinder shutoff and valve timing overlap in order to vent the intake through the exhaust valves.

The wastegate just handles boost control at the exhaust side, but a BOV/BPV, or in this case the VANOS system, vents the pressure that already exists in your intake side.

Presumably, you still have the VANOS system active in the same way, hence why it's still venting and not surging.

I'm assuming the throttle blade remains open even when the throttle pedal is released, allowing boost to travel through the motor as opposed to backing up into the compressor blade. This would explain why there is no vacuum in the intake manifold to operate a traditional BOV. I'm sure VANOS is helping facilitate this as well.

 

[Bflood]

We don’t have a vacuum source for Bob’s which is why nobody uses them. I have big boosts turbo kit on the car, they were supposed to send me the bov set up but that’s another story, however the owner told me it’s not even necessary.

The factory wastegate is somehow able to control/ throttle how boost pressure is released. If you're using an external WG than a BOV should be used.

There are ways to reference boost.. I'm using an adapter for a BOV and Fueltech ECU.

https://vargasturbo.com/product/vtt-billet-bmw-b58-vacuum-boost-adapter/

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