2 BOVs

[trbotaln]

whats up guys, I was looking through an old issue of sport compact car magazine and I noticed their was an old single turbo supra with 2 BOVs right next to eachother on the intercooler piping. Has anyone tried this on a dsm or is it not a good idea?

 

[Shadowfax]

The reason you put it closer to the TB is because when the throttle plate is closed, THAT is where pressure is going to build highest the fastest. You want to vent the pressure as it STARTS to build, not after it is already backed up all the way through the intake tract.

Once more- AND WHAT DOES THAT HURT?!?! Nothing. The only thing in the whole of your car that will be affected by pressure spikes is the turbo. That is the ONLY point of a BOV.

If your intercooler is THAT restrictive that the path of least resistance is back towards the turbo, then you have an issue that you don't solve by putting a bov there. It's counterintuitive. Turn the boost down to a level where it ISN'T a restriction

And that's not? Sure, I'll turn down my boost so I don't have a problem anymore... That's a bandaid. If you boost is high enough and your car loves the power- then keep it that way- don't make your car slower just because your brain is. Does the turbo really care if you vent from the TB vs the IC? Only because it may live longer Otherwise the turbo's whole goal is to stay spooled... to keep pumping out air- if there is no pressure against it- it will do perfectly well.

...all keeping it up and venting through a bov is doing is making the turbo work harder to see the exact same pressure going into the engine.

The turbo doesn't "work harder" in this case- you took your foot off the gas, the turbo merely needs to continue to not have resistance on it and it will continue to spin - this means it stays spooled, and happens to result in ready power as soon as you open it up- that's why you have a BOV. ANSWER IT yourself- what is the ONLY thing that will impede a turbo's comp wheel from spinning? Backpressure from the IC tract.

You should not have this problem. If you do, you don't bandaid it with a bov.

Turning down the boost is SUCH a better idea Why don't you turn down the boost for a slipping clutch too? Getting knock from not enough fuel, don't FIX the problem, turn down the boost...
Seriously- I'm not saying that it's a 100% fix- I'm saying it works well, and if you just have the BOV by the turbo instead of by the TB then it's not a bandaid - it's just where it is.
Tell me this- are you going to tell the WRX guys to install the BOV on the TB tube instead of the IC where it's mounted stock?!? Do THEY have issues because their BOV is SOOOO FAR AWAY!?

Longer IC piping should make this even less of an issue, not more.

Sure, tell that to pipeline guys, or your local water company. They have SO much problems with those dang short lines.

Shorter piping is going to make pressure at an obstruction build more quickly throughout the tract, and surge will be much more apparent. What overflows first, a shotglass or a wineglass?

The problem is that you have over simplified. Your intake system isn't either- it's a line, to a resevoir to a line to the TB. You are looking at the whole system not taking into account the transitions. You have pressure coming out of the turbo. You have it barrelling down the IC pipe to the IC- there it expands and meets resistance (doesn't even have to be a lot) and then it passes thru and finds it has to compress back down to the IC piping (which if you are properly made then this is hardly an issue) and then to the TB. If you have the TB open- then the whole tract is high pressure bleeding to lower pressure.
So when you slam the TP shut- you get a pressure build there... but pressure starts building at the next restriction point too- the air in the IC doesn't keep barrelling on leaving lesser pressure behind it. The whole system starts to expand like a ballon- there is no low pressure area any more- it bleeds every way possible- which simply leaves on spot where gas COULD find lower pressure- the compressor. As soon as you slam the TP shut- you've got decel on the turbine- that will cause less pressure to come from the comp. That's the ONLY lowering pressure spot in the system.
So you've got a major pressure spike at the TP and a minor one at the IC- which one hurts? The one at the IC is closer.

And as far as the bov actuating multiple times, that means you have it adjusted too tight. It isn't opening fully, and is fluttering as a result.

Sure tell that to guys running stock BOV's Tighten it. Replace it... oh they do... oh it still happens. The BOV can act like you said- it can also see enough pressure build multiple times to actuate multiple times.

Back to the topic, the only reason I could see for 2 bovs is to utilize smaller, faster reacting valves, but still have enough overall area to release all the pressure in a high boost scenario.

glad you are so far sighted.

 

[suicidal2af]

Once more- AND WHAT DOES THAT HURT?!?! Nothing. The only thing in the whole of your car that will be affected by pressure spikes is the turbo. That is the ONLY point of a BOV.

If pressure builds at the throttle plate, it is very quickly going to build all the way in the intake tract, and cause COMPRESSOR SURGE. You're not going to build pressure in just the first inch, it's going to build all the way through the tract very quickly.

And that's not? Sure, I'll turn down my boost so I don't have a problem anymore... That's a bandaid. If you boost is high enough and your car loves the power- then keep it that way- don't make your car slower just because your brain is. Does the turbo really care if you vent from the TB vs the IC? Only because it may live longer Otherwise the turbo's whole goal is to stay spooled... to keep pumping out air- if there is no pressure against it- it will do perfectly well.[/b]
Your car obviously DOESN'T love the problem, since your shitty ic isn't letting the air flow. The real solution is to get a better flowing IC. Anytime the turbo is spooled, it is flowing air. If you have the bov before the IC, and the IC is THAT much of a restriction, you're going to be venting air...if the turbo is flowing 25psi and you're venting 10 of it so that it doesn't surge, you're seeing 15 at the manifold. Tell me why turning down the boost is a bad idea?

The turbo doesn't "work harder" in this case- you took your foot off the gas, the turbo merely needs to continue to not have resistance on it and it will continue to spin - this means it stays spooled, and happens to result in ready power as soon as you open it up- that's why you have a BOV. ANSWER IT yourself- what is the ONLY thing that will impede a turbo's comp wheel from spinning? Backpressure from the IC tract.

If you take your foot off the gas, the turbo is still going to be flowing air if it is spooled. Presure is going to build from the TB back, not from the IC back. Unless you have a really shitty IC, in which case see above. If the IC is enough of a restriction to cause surge, it's going to happen whether you're on the throttle or not...if the turbo needs to put out 25psi in order to get 15 to the manifold, it's working harder for no reason. Turn the boost down until you get a better flowing IC, champ.

Turning down the boost is SUCH a better idea Why don't you turn down the boost for a slipping clutch too? Getting knock from not enough fuel, don't FIX the problem, turn down the boost...
Seriously- I'm not saying that it's a 100% fix- I'm saying it works well, and if you just have the BOV by the turbo instead of by the TB then it's not a bandaid - it's just where it is.
Tell me this- are you going to tell the WRX guys to install the BOV on the TB tube instead of the IC where it's mounted stock?!? Do THEY have issues because their BOV is SOOOO FAR AWAY!?

Turning the boost down is the bandaid that makes sense. Getting a better flowing IC is the solution. Comparing it to knock from being too lean is a bad comparison -- getting knock from too much dynamic compression is a good comparison. Turn down the boost until you get better gas in that scenario.

As far as rexes go, have you looked at one? The tmic connects DIRECTLY to the TB. The endtank where the bov is located just happens to be the endtank that connects to the TB. Reference(thx to my scooby friend): http://www.airpowersystems.com.au/wrx/my01/new_tmic/tmic_installed.jpg

Sure, tell that to pipeline guys, or your local water company. They have SO much problems with those dang short lines.
The problem is that you have over simplified. Your intake system isn't either- it's a line, to a resevoir to a line to the TB. You are looking at the whole system not taking into account the transitions. You have pressure coming out of the turbo. You have it barrelling down the IC pipe to the IC- there it expands and meets resistance (doesn't even have to be a lot) and then it passes thru and finds it has to compress back down to the IC piping (which if you are properly made then this is hardly an issue) and then to the TB. If you have the TB open- then the whole tract is high pressure bleeding to lower pressure.
So when you slam the TP shut- you get a pressure build there... but pressure starts building at the next restriction point too- the air in the IC doesn't keep barrelling on leaving lesser pressure behind it. The whole system starts to expand like a ballon- there is no low pressure area any more- it bleeds every way possible- which simply leaves on spot where gas COULD find lower pressure- the compressor. As soon as you slam the TP shut- you've got decel on the turbine- that will cause less pressure to come from the comp. That's the ONLY lowering pressure spot in the system.
So you've got a major pressure spike at the TP and a minor one at the IC- which one hurts? The one at the IC is closer.

You've completely ignored the fact that when the bov opens, that evacuated air is going to create a low pressure area, and keep the air flowing towards the TB. Again -- if you're ic is that much of a restriction, you've got more to worry about than bov placement. With the amount of pressure we're talking about here, restrictions as small as a bend in the piping aren't going to make that noticeable of an effect as to cause surge.

Sure tell that to guys running stock BOV's Tighten it. Replace it... oh they do... oh it still happens. The BOV can act like you said- it can also see enough pressure build multiple times to actuate multiple times.

If it is fluttering, it is too tight or too restrictive. The thing you fail to see is that if there is still enough pressure to actuate it, it's going to STAY open...unless it is too tight.

glad you are so far sighted.

Not even going to dignify this with a response.

I'm not saying that moving it before the ic is a bad thing...it's just not a good thing, either. I would prefer to vent at the source of the pressure buildup than farther back in the tract...it just makes sense.

 

[Shadowfax]

If pressure builds at the throttle plate, it is very quickly going to build all the way in the intake tract, and cause COMPRESSOR SURGE. You're not going to build pressure in just the first inch, it's going to build all the way through the tract very quickly.

okay last time- and so what does that hurt? Nothing but the turbo- the BOV is supposed to protect the turbo- we're really mincing on the little shit here since really we both agree that in 90% of the time it doesn't matter anyway- but the point I'm trying to make is that the ONLY thing hurt by boost spike is the turbo. The turbo. The turbo.

Your car obviously DOESN'T love the problem, since your shitty ic isn't letting the air flow. The real solution is to get a better flowing IC. Anytime the turbo is spooled, it is flowing air. If you have the bov before the IC, and the IC is THAT much of a restriction, you're going to be venting air...if the turbo is flowing 25psi and you're venting 10 of it so that it doesn't surge, you're seeing 15 at the manifold. Tell me why turning down the boost is a bad idea?

tell me why putting a BOV by the turbo is? you're saying the air simply backs up starting at the TB and then works backwards towards the turbo. I'm agreeing, but saying that it also starts backing up at the IC inlet- even if it's a well flowing IC- it will STILL have a secondary pressure spike start there. There is only ONE thing that matters - relieving stress on the turbo.

If you take your foot off the gas, the turbo is still going to be flowing air if it is spooled. Presure is going to build from the TB back, not from the IC back. Unless you have a really shitty IC, in which case see above. If the IC is enough of a restriction to cause surge, it's going to happen whether you're on the throttle or not...if the turbo needs to put out 25psi in order to get 15 to the manifold, it's working harder for no reason. Turn the boost down until you get a better flowing IC, champ.

again, you're looking at things oddly- the turbo doesn't need to push 25psi to get 15 to the manifold- course with longer IC pipes you'd be amazed at the pressure differential. But the point is that how could the IC NOT cause a pressure spike.

Look at it this way- you've got a solid 15psi in all your pipes from TB to the turbo (yeah right) and you slam the TP shut- if your turbo is still pumping air- which you just shut the TP so your exhaust is decreasing which causes your turbo to decel - then it's pumping it into a 15psi situation- if you only have 15psi coming from your turbo- what will happen to it? If you have 10psi from the turbo what happens, if you have 20psi what happens?

Turning the boost down is the bandaid that makes sense. Getting a better flowing IC is the solution. Comparing it to knock from being too lean is a bad comparison -- getting knock from too much dynamic compression is a good comparison. Turn down the boost until you get better gas in that scenario.

Why not turn down your timing? Increase your fuel amount? Get lower comp pistons, get a better IC- there are a million ways to do it. Examine for one moment why my idea is BAD. What's the reason? If you can put or move your BOV to right beside the turbo- then why is that bad? Again, we're arguing over a VERY small percentage of the issue here, cause most of the time there's little difference anywhere.

As far as rexes go, have you looked at one? The tmic connects DIRECTLY to the TB. The endtank where the bov is located just happens to be the endtank that connects to the TB. Reference(thx to my scooby friend): http://www.airpowersystems.com.au/wrx/my01/new_tmic/tmic_installed.jpg

Hmm, I never really paid attention to the fact that they connected like that- I've little exposure to them but I did notice the BOV on the IC- my respect doesn't really go down much- cause I think that in the IC is probably the better compromise

You've completely ignored the fact that when the bov opens, that evacuated air is going to create a low pressure area, and keep the air flowing towards the TB. Again -- if you're ic is that much of a restriction, you've got more to worry about than bov placement. With the amount of pressure we're talking about here, restrictions as small as a bend in the piping aren't going to make that noticeable of an effect as to cause surge.

I didn't ignore it- I understand it, but it's of little relevance in this particular issue- I'm not saying (again) that it doesn't work well enough, that point is moot- but you are still ignoring the fact that you aren't dealing with 20 ft of tubing and 15 90 degree bends- step away from the DSM and look at the less than ideal and you might see that I'm not a crack head The difference is that I understand what you are saying, and agree that it works well enough, however that doesn't mean it's the ideal setup, nor that it will solve issues that you've never dealt with and refuse to acknowledge.

If it is fluttering, it is too tight or too restrictive. The thing you fail to see is that if there is still enough pressure to actuate it, it's going to STAY open...unless it is too tight.

I don't fail to see that- neither do I fail to see that if it actuates and releases the pressure spike from the TB, and there is more air and pressure coming thru the IC's and then it reaches the BOV- suddenly it sees enough to actuate again... and again... and again...
I see your points, you don't see mine. I've been thru this arguement, and all that I can say is that when a BOV was installed between the IC and the turbo, the symptoms STOPPED. Not going to say the problem was cured- because yes, the issue is that the IC system isn't ideal, there is no arguement there- however if you just put the BOV between the two in the first place, you likely wouldn't have noticed.
Here's one more for ya- is it good to have your BOV mounted at the TP when running Blow thru? (I see both pro's and con's - I've not tested enough to have a good answer yet myself- just something to think of)

Not even going to dignify this with a response.

Probably a good idea, it was a short cheap shot- but I couldn't think of anything else to say and I can't just let it drop now could I?

I'm not saying that moving it before the ic is a bad thing...it's just not a good thing, either. I would prefer to vent at the source of the pressure buildup than farther back in the tract...it just makes sense.

You would prefer to vent at the build up, not at where build up does damage? That's my whole issue. Why would you care to vent AT THE BUILD UP? The build up doesn't hurt anything EXCEPT THE TURBO. Why not vent at the danger spot, eliminating the merest possibilty of damage? The biggest thing going for you is that 90% of all turbo cars have the BOV there. It's easy, it's quick, it's simple. It's also louder.
Ask this- if you vent at the turbo - and there is still pressure spike at the TP when it opens back up couldn't that be useful (assuming that you could take advantage of it instead of simply go lean? )

The point comes back to us debating on the fraction of the issue- it's a good read, you've made your points, I've made mine - some people will try what I said, and most will do what you've said. I have no desire to let this degenerate into flaming- we've done pretty well of staying on debate, if only slightly on topic I respect your opinion, I may disagree, but thanks for debating.

 

[suicidal2af]

okay last time- and so what does that hurt? Nothing but the turbo- the BOV is supposed to protect the turbo- we're really mincing on the little shit here since really we both agree that in 90% of the time it doesn't matter anyway- but the point I'm trying to make is that the ONLY thing hurt by boost spike is the turbo. The turbo. The turbo.




tell me why putting a BOV by the turbo is? you're saying the air simply backs up starting at the TB and then works backwards towards the turbo. I'm agreeing, but saying that it also starts backing up at the IC inlet- even if it's a well flowing IC- it will STILL have a secondary pressure spike start there. There is only ONE thing that matters - relieving stress on the turbo.





again, you're looking at things oddly- the turbo doesn't need to push 25psi to get 15 to the manifold- course with longer IC pipes you'd be amazed at the pressure differential. But the point is that how could the IC NOT cause a pressure spike.

Look at it this way- you've got a solid 15psi in all your pipes from TB to the turbo (yeah right) and you slam the TP shut- if your turbo is still pumping air- which you just shut the TP so your exhaust is decreasing which causes your turbo to decel - then it's pumping it into a 15psi situation- if you only have 15psi coming from your turbo- what will happen to it? If you have 10psi from the turbo what happens, if you have 20psi what happens?


Why not turn down your timing? Increase your fuel amount? Get lower comp pistons, get a better IC- there are a million ways to do it. Examine for one moment why my idea is BAD. What's the reason? If you can put or move your BOV to right beside the turbo- then why is that bad? Again, we're arguing over a VERY small percentage of the issue here, cause most of the time there's little difference anywhere.

Hmm, I never really paid attention to the fact that they connected like that- I've little exposure to them but I did notice the BOV on the IC- my respect doesn't really go down much- cause I think that in the IC is probably the better compromise



I didn't ignore it- I understand it, but it's of little relevance in this particular issue- I'm not saying (again) that it doesn't work well enough, that point is moot- but you are still ignoring the fact that you aren't dealing with 20 ft of tubing and 15 90 degree bends- step away from the DSM and look at the less than ideal and you might see that I'm not a crack head The difference is that I understand what you are saying, and agree that it works well enough, however that doesn't mean it's the ideal setup, nor that it will solve issues that you've never dealt with and refuse to acknowledge.


I don't fail to see that- neither do I fail to see that if it actuates and releases the pressure spike from the TB, and there is more air and pressure coming thru the IC's and then it reaches the BOV- suddenly it sees enough to actuate again... and again... and again...
I see your points, you don't see mine. I've been thru this arguement, and all that I can say is that when a BOV was installed between the IC and the turbo, the symptoms STOPPED. Not going to say the problem was cured- because yes, the issue is that the IC system isn't ideal, there is no arguement there- however if you just put the BOV between the two in the first place, you likely wouldn't have noticed.
Here's one more for ya- is it good to have your BOV mounted at the TP when running Blow thru? (I see both pro's and con's - I've not tested enough to have a good answer yet myself- just something to think of)

Probably a good idea, it was a short cheap shot- but I couldn't think of anything else to say and I can't just let it drop now could I?

You would prefer to vent at the build up, not at where build up does damage? That's my whole issue. Why would you care to vent AT THE BUILD UP? The build up doesn't hurt anything EXCEPT THE TURBO. Why not vent at the danger spot, eliminating the merest possibilty of damage? The biggest thing going for you is that 90% of all turbo cars have the BOV there. It's easy, it's quick, it's simple. It's also louder.
Ask this- if you vent at the turbo - and there is still pressure spike at the TP when it opens back up couldn't that be useful (assuming that you could take advantage of it instead of simply go lean? )

The point comes back to us debating on the fraction of the issue- it's a good read, you've made your points, I've made mine - some people will try what I said, and most will do what you've said. I have no desire to let this degenerate into flaming- we've done pretty well of staying on debate, if only slightly on topic I respect your opinion, I may disagree, but thanks for debating.

It's always better to alleviate a problem where it starts, and not at where it will eventually end up. If you were a dictator of a country, would you rather defend your country at its gates, or miles away where the enemy is massing their troops?

The thing is, your ic REALLY should not be restrictive enough to cause a spike in pressure in front of it. When your bov opens and releases all of that pressure, you now have exactly 1 atmosphere(assuming sea level) under the bov, and quite a bit more pressure everywhere else in the intake tract. Air flows through the path with the least resistance, and if it is flowing towards a compressor wheel(which is creating more pressure as it spins, mind you) as opposed to towards an open valve with no pressure, you have a SERIOUS issue with your ic. And if it is that much of a restriction in flow, then yes, you will have a very large difference in pressure at the turbo and at the manifold, which means you need to turn the boost down until you get that taken care of .

Any fluid dynamics engineers wanna chime in and put an end to this debate?

 

[Shadowfax]

Any fluid dynamics engineers wanna chime in and put an end to this debate?

A fluid dynamics engineer is who got me started on this subject

Because he owns a 1st gen AWD with an EVO16G and he was curious about BOV's what their true purpose is. It cannot be argued that it's to relieve pressure on the turbo. So here we are. The point? Is your turbo generating more pressure than it just had? If you have a 16G that could produce 20psi, and is at 7000RPM, when you let off the gas- IS it producing 20psi? Is it producing 15? More importantly, is it getting resistance to the pressure it's creating? If there is pressure against the turbo, and it's not relieved, is it not working against the turbo?

Once more, the turbo is all that matters. The pressure that builds against the turbo, any time the turbo has more pressure pushing against it rather than flowing away it's bad.

Your analogy of the city is incorrect.

You are the ruler of a country. You have a huge treasury, in your capital city. Do you defend your kingdom's boarder or your capital city? The turbo is ALL that matters.

But once more- only in theory- one is not really better than the other on most cars, or in most situations. In most cases by the TB works- yes the pressure flows towards the BOV, typically the IC is decent enough, typically there aren't 20 ft and 14 or 15 90 degree bends. Typically we're both retards for continuing a debate on something this semi-trivial.

One more time- explain why the BOV at the turbo is bad, why do some turbos come with integrated BOV's if I'm wrong?

 

[ZenkaiRacerDsM]

You are both almost saying the same stuff.... And I cant believe you both rambled on this long about how a BOV works... Like what was said... its almost common sense. At least you would think.

 

[Shadowfax]

You are both almost saying the same stuff.... And I cant believe you both rambled on this long about how a BOV works... Like what was said... its almost common sense. At least you would think.

yes we are nearly saying the same thing- and yes it's nearly pointless at this point. But we've rambled on this long, might as well ramble on some more!

 

[suicidal2af]

You are both almost saying the same stuff.... And I cant believe you both rambled on this long about how a BOV works... Like what was said... its almost common sense. At least you would think.

This was a very pointless post. We're arguing the placement of it, not how it works. If anything, the best area for placement is a far more complicated subject than how it works.

I know this forum has at least a couple fluid dynamics engineers on it, where are they when you need one?

Even if the turbo isn't putting out its full pressure when you let off the gas, the lowest pressure in the tract is going to be where the bov has just vented. If you defeat the enemy at your border, can they get to your treasury? Nope

 

[Shadowfax]

This was a very pointless post. We're arguing the placement of it, not how it works. If anything, the best area for placement is a far more complicated subject than how it works.

agreed

Even if the turbo isn't putting out its full pressure when you let off the gas, the lowest pressure in the tract is going to be where the bov has just vented. If you defeat the enemy at your border, can they get to your treasury? Nope

IF you can defeat your enemy then you'd be correct. But if you have all your troops at the border defending the masses there, and anyone slipped in - you're leaving your treasury totally at risk.

Fortify that which is strong, and you'll never lose it. Risk it, and you may turn out okay, but it only takes once for you to lose big.

 

[psychlow]

A benefit to placing the BOV near the TB is that the air from the I/C pipes is still rushing toward the TB when you open the throttle plate back up. The air escaping the BOV will cause the air around it to rush toward the BOV opening due to the negative change in pressure in that area. The displacement of that air in turn pulls the molecules around them in the same direction, and so on, and so on.

So, rather than sucking the air from the I/C pipes backwards through the I/C and back toward the turbo, and then reversing their direction when you start boosting again, you keep the molecules running in the same direction the entire time. This should reduce after-shift spool time by allowing the turbo to repressurize the intake tract with less required energy.

It'd be such a small, minute difference it's stupid to argue about it, but hey, I guess it's something to do.

 

[Shadowfax]

It'd be such a small, minute difference it's stupid to argue about it, but hey, I guess it's something to do.

pretty much

 

[theNEW]

Ok, I didn't read most of the arguments on this page, but I can tell you from a couple things and correct what should be said.

Running the bov closer to the tb is the ideal position. This is the best place to eliminate comp. surge. Which is why the stock dsm bov is also placed on the tb side of the piping of the intercooler.

Running the bov closer to the turbo does not allow enough built pressure to be vented caused by the closing of the tb plate. Comp Surge is when built pressure is not released, violently banging against the compressor. This shortens the life of the turbo drasticly.

I have a supra and am still on the stock twins, therefore I have no need for 2 bovs. This is only done when there are tremendous amounts of air being pushed through. (Single turbo supras) because one (regular bov = hks ss generally) can not release enough pressure. Once bov could be run. But is usually the greddy type r or hks racing, and many still opt to run a second regualar(hks ss) to eliminate surge.

 

[Shadowfax]

Running the bov closer to the turbo does not allow enough built pressure to be vented caused by the closing of the tb plate. Comp Surge is when built pressure is not released, violently banging against the compressor. This shortens the life of the turbo drasticly.

again- I would LOVE to see how a BOV right beside the turbo allows pressure to bang against the compressor.

 

[theNEW]

again- I would LOVE to see how a BOV right beside the turbo allows pressure to bang against the compressor.

Pressure built after the bov, not vented properly.

 

[Shadowfax]

Pressure built after the bov, not vented properly.

if pressure is after the BOV- and the TP is shut- where does pressure go? Back towards BOV - if the BOV sits between the pressure spike and the Turbo...