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Yeah, Another Bov Thread.

CEF33Y

By CEF33Y,
in Engines & Forced Induction

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CEF33Y Experienced

CEF33Y

Posted
Posted

So, I currently do not run a bov of any kind.

My setup, RB20, hypergear op6 highflow, usual supporting mods. Nistune.

240rwkw. With a fair smack of lag, lol.

In past non-bov equiped cars, i've had the zu tututu/ compressor chop/ dose noise. When fitted with a bov, obviously the noise goes away, but difference in performance, or boost drop off between gears felt negligible. (as what most things I've read/searched)

Current setup however, feels a bit different.

If I get it on boost (>12psi) then lift to change gears, I dont tend to get the compressor chop, just one big choof, almost like an atmo bov. Also notice a fair drop off between gears.

So afaik, the 'dose' noise is intake air coming out though the turbo, afm, etc slowing the turbo down (but not completely stopping it)

One big choof would potentially mean the turbo is stopping?(or slowing down much more)

Also, being a standard size core style turbo, would assume inertia would be rather low, compared to a much larger turbo.

Do you guys, in this instance think a bov would assist in getting it back on boost after a gearchange?

Cheers

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KiwiRS4T Grand Master

KiwiRS4T

Posted
Posted

So, I currently do not run a bov of any kind.

My setup, RB20, hypergear op6 highflow, usual supporting mods. Nistune.

240rwkw. With a fair smack of lag, lol.

In past non-bov equiped cars, i've had the zu tututu/ compressor chop/ dose noise. When fitted with a bov, obviously the noise goes away, but difference in performance, or boost drop off between gears felt negligible. (as what most things I've read/searched)

Current setup however, feels a bit different.

If I get it on boost (>12psi) then lift to change gears, I dont tend to get the compressor chop, just one big choof, almost like an atmo bov. Also notice a fair drop off between gears.

So afaik, the 'dose' noise is intake air coming out though the turbo, afm, etc slowing the turbo down (but not completely stopping it)

One big choof would potentially mean the turbo is stopping?(or slowing down much more)

Also, being a standard size core style turbo, would assume inertia would be rather low, compared to a much larger turbo.

Do you guys, in this instance think a bov would assist in getting it back on boost after a gearchange?

Cheers

That's what BOVs are for. AFAIK the only commercial bovless setups are for low boost applications.

Dose Pipe Sutututu Grand Master

Dose Pipe Sutututu

Posted
Posted

Yep

Can hold my TD06 still with the car running and noting changes

Maybe not on a large turbo I'm confident a stock turbo if you were to grab the shaft whilst the engine is running it would stall as there's not enough exhaust gases being relieved as the rear wheel is so small

GTSBoy Grand Master

GTSBoy

Posted
Posted

Maybe not on a large turbo I'm confident a stock turbo if you were to grab the shaft whilst the engine is running it would stall as there's not enough exhaust gases being relieved as the rear wheel is so small

How does the rotation of the wheel change the % open area it has in the turbine exducer?

zebra Grand Master

zebra

Posted
Posted

Maybe not on a large turbo I'm confident a stock turbo if you were to grab the shaft whilst the engine is running it would stall as there's not enough exhaust gases being relieved as the rear wheel is so small

Did it to both of the standard CT12a's

Don't get much smaller than that.

GTSBoy Grand Master

GTSBoy

Posted
Posted

logically, if you're halting exhaust flow from a motor.. it would stall right?

But you're not. There are great big open gaps between the fins of the turbine. They are always there, regardless of whether the turbine is spinning or not. You could spin it backwards, forwards, keep it stopped, plug half of them up with putty, and it wouldn't stall the motor.

Blackkers Experienced

Blackkers

Posted
Posted

A fuel injected engine will keep running under huge amounts of extra exhaust pressure so long as it can get fresh intake air

Stopping the turbo from spinning doesn't seal anything. People have seized turbos from lack of oil or w/e and still been able to drive home from the strip haha

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