Compressor surge, bad for carbs?

[rerb]

Does anyone here not use a BOV? if so I'm curious if removing mine would damage anything other than the turbo. My thought is without the quick release of pressurized air from the BOV, would closing the throttle at boost damage the slides in the carbs since they'll still be experiencing 12+ psi of boost? My td05 is an extremely cheap Eblag one, and I'm planning an upgrade soon, so I'm not too worried about it. My issue is that the BOV hits the engine case and due to the awkward angle of the silicone pipe connecting it, leaks out boost. For the time being I plan to delete it with a pipe, but don't want to damage anything. ny not having a BOV while I build a new setup. Thanks.

[Gixer1460]

Don't have experience myself but have seen a 'ghetto' install that was done by a 'well known' tuner for a shootout that didn't have a BOV and he managed to blow the carb tops clear off - whether through over boost or over-run boost spike I don't know, either way it went with a bang.

IMO, the thing is, when closing the throttle @ 12psi boost, the already generated air flow which has velocity will hit the closed butterflies and can bend them, but because the air speed drops due to the restriction its pressure spikes upwards and is reflected back to the compressor blades possibly bending them. They may not break immediately but cycles of doing it over and over will fatigue them and they could break at WOT and then get ingested into the engine! So its not just the cheap Chinky turbo you risk but the engine as well!

Personally i'd keep the BOV and fix the connection problem !

[Reinhoud]

8 hours ago, rerb said:

Does anyone here not use a BOV? if so I'm curious if removing mine would damage anything other than the turbo. My thought is without the quick release of pressurized air from the BOV, would closing the throttle at boost damage the slides in the carbs since they'll still be experiencing 12+ psi of boost? My td05 is an extremely cheap Eblag one, and I'm planning an upgrade soon, so I'm not too worried about it. My issue is that the BOV hits the engine case and due to the awkward angle of the silicone pipe connecting it, leaks out boost. For the time being I plan to delete it with a pipe, but don't want to damage anything. ny not having a BOV while I build a new setup. Thanks.

I don't think not having a BOV is bad for a turbo, the only car I have seen what has a BOV from factory was a Lancer EVO.

 

 

Edited July 26, 2021 by Reinhoud

[rerb]

On 7/26/2021 at 2:51 AM, Gixer1460 said:

Don't have experience myself but have seen a 'ghetto' install that was done by a 'well known' tuner for a shootout that didn't have a BOV and he managed to blow the carb tops clear off - whether through over boost or over-run boost spike I don't know, either way it went with a bang.

IMO, the thing is, when closing the throttle @ 12psi boost, the already generated air flow which has velocity will hit the closed butterflies and can bend them, but because the air speed drops due to the restriction its pressure spikes upwards and is reflected back to the compressor blades possibly bending them. They may not break immediately but cycles of doing it over and over will fatigue them and they could break at WOT and then get ingested into the engine! So its not just the cheap Chinky turbo you risk but the engine as well!

Personally i'd keep the BOV and fix the connection problem !

Makes sense. Better safe than sorry, thanks fore the answer. 

[Reinhoud]

I do notice with my own bike that when I close the throttle the boost pressure goes up, by at least 4/5 psi

[1260Pete1]

Yep I run most of my cars and bikes without and they run and also sound better, anything over 11psi though I definitely run with them 

[ApocWarrior]

14 hours ago, 1260Pete1 said:

Yep I run most of my cars and bikes without and they run and also sound better, anything over 11psi though I definitely run with them 

It seems like a "what you can get away with" scenario.

Until my piston swap, I'm at 8psi and I don't even want that much banging throttle shut.

Stock carbs have semi porous plastic slide material compared to most car's metal butterflies.

I say if it causes turbo wear, reduce it.

Just my impression.

[1260Pete1]

10 hours ago, ApocWarrior said:

It seems like a "what you can get away with" scenario.

Until my piston swap, I'm at 8psi and I don't even want that much banging throttle shut.

Stock carbs have semi porous plastic slide material compared to most car's metal butterflies.

I say if it causes turbo wear, reduce it.

Just my impression.

Just cause any turbo wear and the carbs have no problems with it

[colinworth79]

On 7/26/2021 at 10:27 AM, Reinhoud said:

I don't think not having a BOV is bad for a turbo, the only car I have seen what has a BOV from factory was a Lancer EVO.

 

 

I've not see a car without a bov fitted as standard. Ford, Vw /audi volvo etc. Lots are built into the compressor housing of the turbo. 

[1260Pete1]

5 minutes ago, colinworth79 said:

I've not see a car without a bov fitted as standard. Ford, Vw /audi volvo etc. Lots are built into the compressor housing of the turbo. 

Yep most redirect it back into the I take, I run all my cars without and the sound is much better.

[Reinhoud]

Probably on the newer cars then..

Edited November 16, 2021 by Reinhoud

[rerb]

On 11/14/2021 at 9:43 AM, 1260Pete1 said:

Yep most redirect it back into the I take, I run all my cars without and the sound is much better.

I deleted the diverter valve on my audi, it sounds great. But it also hurts spool time a little. I was much more confident doing that on a car than a bike, because the car has a single, beefy butterfly valve, and the bandit's carbs have the more fragile slides as was previously mentioned. 

I have found a nice in-between though ,the HKS sequential blow off doesn't fully open below 6 or so PSI, so on low boost I still get some nice flutter but at the same time I still get that satisfying "chirp" from it at high boost 

[1260Pete1]

38 minutes ago, rerb said:

I deleted the diverter valve on my audi, it sounds great. But it also hurts spool time a little. I was much more confident doing that on a car than a bike, because the car has a single, beefy butterfly valve, and the bandit's carbs have the more fragile slides as was previously mentioned. 

I have found a nice in-between though ,the HKS sequential blow off doesn't fully open below 6 or so PSI, so on low boost I still get some nice flutter but at the same time I still get that satisfying "chirp" from it at high boost 

The carbs don't have a problem running without, the slides won't be effected it's the throttle blades that would take any stick.