Chaincase?

[Mike P]

This is incorrect. A boost re circulation valve does the same this as a BOV. The only reason its rerouted back to the intake on the sidewinder would be for noise. Most turbo cars use a boost recirculation because they are MAF, the sidewinder is speed density, the air is not metered so it can be vented to atmosphere without any ill effects. Every turbo vehicle needs one or the other. The lag present on the 1100 turbo motor is probably due to the fact that it has one throttle body, which is 10 inches or so from the cylinder head. The yamaha 3 cylinders have 3 throttle bodies, about an inch away from the cylinder head.

Without a BRV or BOV, once you close the throttles, the boost in the charge tube would have nowhere to go but back through the turbo compressor wheel, this is not only bad for the turbo, but causes the turbine wheels in the turbo to slow down considerably. This would make for serious lag when going from on the throttle to off the throttle to back on. With the BRV/BOV, when you let of the throttle, the vacuum causes the valve to open, vents the compressed air and this allows the turbo to keep spinning fast while the throttle is close. This results in minimal lag in an on/off/on throttle situation.

 

[cannondale27]

Yamaha is claiming some charge is held in the intake. Could be true since they use Iacv for idle so it's possible the butterfly's are closed and sealed even at idle.

 

[**sj**]

This is incorrect. A boost re circulation valve does the same this as a BOV. The only reason its rerouted back to the intake on the sidewinder would be for noise. Most turbo cars use a boost recirculation because they are MAF, the sidewinder is speed density, the air is not metered so it can be vented to atmosphere without any ill effects. Every turbo vehicle needs one or the other. The lag present on the 1100 turbo motor is probably due to the fact that it has one throttle body, which is 10 inches or so from the cylinder head. The yamaha 3 cylinders have 3 throttle bodies, about an inch away from the cylinder head.

Without a BRV or BOV, once you close the throttles, the boost in the charge tube would have nowhere to go but back through the turbo compressor wheel, this is not only bad for the turbo, but causes the turbine wheels in the turbo to slow down considerably. This would make for serious lag when going from on the throttle to off the throttle to back on. With the BRV/BOV, when you let of the throttle, the vacuum causes the valve to open, vents the compressed air and this allows the turbo to keep spinning fast while the throttle is close. This results in minimal lag in an on/off/on throttle situation.

although the throttle body distance from the head represents slower response time...actually on the zuk 1100 turbo...the more boost the more lag since there is lag from the BOV routed back into the intake and compressor stall....the stock BOV attempts to stutter the dump...but as the boost increases will impact the compressor wheel...most when turning up the boost, end up dumping to the atmosphere...

the sidewinder has relatively low boost stock..and my understanding is its returned to the pressure side... returning it into the pressure side must have some small impact,even considering the low boost... but still features an air bypass valve...so it returns the boost to the pressure side...but at full boost would still have compressor impact ...so my GUESS is that it dumps excess boost to prevent compressor stall?

 

[stevewithOCD]

I believe there's a secret SA valve that they haven't told anybody about. No matter what the BOV or MAF or BRV do, the SA valve will activate when that little plastic thumb flipper moves turning on the "Smile Activator" that makes my cheeks roll back as I scream with joy & ecstasy...