14psi is still pressure, not a vacuum. Vacuum isn't the 'opposite' of pressure, it's the absence of pressure Vacuum can be interpreted as two different things - zero absolute pressure (a perfect vacuum) or as 'less than atmospheric', which is a partial vacuum. As atmospheric pressure is approximately 14psi absolute then we are not using the relative to atmospheric case above. Of course, intake manifold pressure, due to the pressure drop across the throttle bodies etc will cause a partial vacuum relative to atmosphere, but we were ignoring that for this geekily comedic moment. Thus a N/A car runs at 14psi

Not running a BOV will tend to slow it down yes, but when you lift the throttle and all that compressed air has to go somewhere, it CAN stall the compressor , and CAN stop it surprisingly quickly (or rather decellerate it VERY quickly even if it's still turning at a fair old lick. That is one reason why BOV's are used - to stop stalls and sudden speed changes from damaging parts of the turbo.

Again with the drag cars. I thought you meant proper drag cars, not specced up road cars (a BIG difference in my book). If they run no BOV then I bet they have to turn down the boost levels to safe values when not actually drag racing. Not running a BOV of any sort makes no sense from a safety (to the turbo) point of view. If they are running at, say, 25psi boost then why not fit a dump valve rated at, say, 30psi. It won't slow you down, but it will protect the engine.

I don't claim to be an expert on turbocharging (in my opinion the best cars are normally aspirated) so perhaps it's best if others who know more than me argue the case. But it strikes me as though there are flaws in your knowledge too (although I agree with you about irbdizzy or whatever his name is or means).

As always I don't mean to sound agressive. It's a nature of text based communication and trying to make a point clearly that makes it come across this way. If ever you feel put out by my comments I apologise, as I love to have adult conversations about things like this, if only so I can learn more from people.

Dont Understand You.

Quote from Real Per4mance :

Make sure you set passengers to "none", otherwise you think they've just opened a shaken can of Coke when you back off.

LOL!

Excellent! Another BOV sound thread. Lets see if it can beat the previous record of BOV thread posts before descending into chaos and insults........

why did you create a new thread for this when you already have an active thread about BOVs?
Seems very pointless and i hope a mod merges the two.

And you've just started it

Threads merged.

nice job, sory to irratate you

Quote from lrdbsi :

ok this is kinda wacked. i made a whistle bov, its loops correctly
but sounds pretty funky, so like or hate it, dont fu*king complain!, keep your mouths shut, i dont want to know your turbo-charging knowledge or about your s15 drift car u have,

install instructions inside:
http://files.filefront.com/whi ... /;5100895;;/fileinfo.html

Was this part really necessary? First you ignore a thread already open on bov's, release something that sounds like a bunch of toy canaries having epileptic fits, and swear and insult the community in advance, cause you know not everyone will like it? Great way to meet friends and influence pp dude, why did you bother?

Agreed, totally unneccessary, please engage common sense before filling up the forum with this sort of negative attitude.

Hey, by no means do i claim to know a lot about automotive.... it just riles me up when someone who clearly knows less then what they say they know, starts getting abusive about getting his point across and getting his own way.

I'm still learning and it's something that i love doing. In the last year and a bit i've been apart of an Australian forum called Ausrotary. I have learnt so much from the fellas on there and it's great to jump on and have a read about old, new, good and bad.

Cheers for the info though, it's always good to get some info that isn't forced down your throat with an arrogant attitude

Cheers.

My bro has HKS ssqv in his car, on lower boost it sounds "fluffering" (whatever, I don`t know the right word), but after like 0,5 bar it makes that kinda sound like in the first video.

ps. They sell parts on ssqv which makes it sound like one in the first video.

I hope you understood, cheers.

Well done to Shinanigans for actually getting it right (MajorNut - that 'chirping' sound is NOT the damn wastegate, it's the compressed air getting cut up in blades of the turbo after it gets fed back in - aka: stalling). Tristancliffe, I take my hat off to you as well for knowing your stuff but I disagree about the best cars being NA, it depends on the application surely?

Care to elaborate more on why you think the best cars are NA?

Just personal preference really. To get similar bmep's out of an NA engine it needs to be better engineered than the same FI engine. I'm not a fan of turbo lag, which even in relatively lagless cars is still annoying when you want to load the car midcorner at a moments notice. Engine bays are more irritating to work on as more 'bits' are needed.

If I had to have FI I'd choose a supercharger over a turbo anyday, but I'd rather have NA first. As I say, it's just personal preference.

And if everyone conformed to "what's cool" then the world would be a very boring place, indeed!

The thing i love about turbos is the surge of power that builds up. While i do like the snappiness of a torque filled V8, i just can't get enough of that boost, the spool, the sound, the power, the feeling... it's just a mass rush The first turbo car i ever drove was a Ford Laser TX3 (you guys may not know what they are, but they are a small AWD Turbo 1.8L) My mate had one that was worked and he let me give it a gutfull one night, was scary to say the least... i actually couldn't put the pedal on the floor because i was just so overwhelmed. Since then i've driven more powerful cars that make me laugh at the old TX3, but i still remember the feeling like it was yesterday.

I've also been for a ride in a friends dads Holden HQ Ute (old school) which has a 525rwhp small block V8 in it. Most powerful car i've ever been in, absolutely undescribable. He'd put his foot into it, and just felt like time stood still (maybe it was the massive torque converter? lol)

Well built cars are very cool, regardless of how they get their power, as long as they get it

Thanks G (o) A

:inq:

Never thought that someone who apparently knows so much about cars (aka: Mr. Clarkson) would make such an error, but wrong he is. If that car had a BOV/Dump Valve it wouldn't make that sound...

Makes you wonder how much he really knows..
-it's a pretty geeky thing to know the difference though, especially when "car guys" don't give a rats @$$ what it's called.

other geeky things...

It does make you wonder and I don't really see it being "geeky" to know how something works, especially an engine/turbo when these "car people" who claim to know everything (not that I claim to either ) only help in spreading disinformation.

See if I give a rat's ass if anyone thinks it's "geeky" for that matter.

I have a feeling that many people see the names as interchangeable, and they might just be that..

Maybe they need to be further defined for specific purposes, but in general if someone says either of those, you know what they are talking about within the context of the conversation.

Quote :

I have a feeling that many people see the names as interchangeable

They may well do which is why there are problems and people getting confused - here's a little FAQ I found while searching for some links:

Quote :

Glossary

CHRA = center housing rotating assembly or a turbo without the compressor and exhaust housing but complete from compressor blade to exhaust blade.

Compressor Inducer = smaller diameter of compressor blade (inlet from the air filter)

Compressor Exducer = larger diameter of the compressor blade (outlet to intercooler}

Turbine Inducer = larger diameter of exhaust blade (inlet from the manifold)

Turbine Exducer = smaller diameter of exhaust blade (outlet to exhaust)

Inducer = inlet

Exducer = outlet

A/R= Aspect Ratio or Area / Radius =Different people say different things but basically it is the area of the housing divided by the radius of the housing. As the housing A/R factor increases numerically so does it's potential to induce or exduce a specific volume .

Wastegate (W/G)= Vacuum dependent device used to limit boost by drawing exhaust flow away from the turbine blade. This is done near or before the inducer of the exhaust blade.

Internal Wastegate = This type of wastegate is an integral part of the exhaust housing. It consist of a flapper door inside of the exhaust housing that is controlled by a vacuum/boost referenced actuator valve that is attached to the compressor housing. Most OE manufacturers use this type of setup because it is cheap and there are no fitment problems like those of external wastegates. Because of the flapper door size this type of wastegate is not efficient at high boost levels . Since it can not relieve enough exhaust flow to maintain the maximum boost setting boost creep will sometimes occur when driven hard. Most actuators are preset from the factory with max a boost level that can not be adjusted unless a boost control device is added .There are aftermarket racing actuators on the market have an adjustable rod that allows for boost level changes.

External Wastegate = This type of wastegate is also vacuum/boost referenced but it is separate entity from the turbine section. External wastegates are connected in many different ways but the most efficient method is to connect it with it's own section of piping near the collector flange of the manifold. This type of connection will allow exhaust flow to be drawn from all primary tubes equally. Of course this type can not be applied to all street cars because of the space limitation factor. The physical size of the wastegate valve, which is 35mm or larger for small external wastegates, and connection point makes the external W/G a better choice for mild to wild setups. If the the dump tube for the W/G is to be routed back into the exhaust piping for a closed loop setup it is best to make the tube as long as possible. Flow from the W/G tube that is re-entered back into the exhaust too early can cause a restriction in flow by creating back pressure.

Manual Boost Controller (MBC) = Commonly called VVC (variable valve controller), VBC (variable boost controller) and a couple other unique names. MBC are mechanical devices plumbed between the W/G and it's vacuum/boost source. Basically the MBC will manipulate the vacuum/boost signal to the actuator valve or wastegate. Everything from fish tank valves to reducer T's are used as MBC's. MBC's should be mounted as close as possible to the wastegate to prevent problems that can be caused by using long vacuum lines and it will prevent you from cranking up the boost every time someone spanks your butt.. The main drawback of MBC's is the W/G will begin to open as soon as boost registers even though an MBC has been an properly installed. This premature opening acts almost like an exhaust leak and can hamper the low and mid range performance of your engine.

Electronic Boost Controller (EBC) = Also referred to as EVC (Electronic Valve controller). EBC's use a solenoid box controlled by an ECU. The best EBC's use Fuzzy Logic programming to control the boost and give features that help traction handicapped turbo cars. Unlike the MBC the EBC holds the w/g completely closed until the preset boost level is reached and then it opens completely until the throttle is closed. This feature allows for more low-end and midrange power that may have been lost when using an MBC. Some EBC's can also be setup to use a scramble boost (SB) setting. SB holds the boost at a preset low boost level for a preset amount of time and then it automatically changes to the high boost setting of your choice. Other features of EBC's include gear based boost levels, rpm based boost levels and hi/lo settings.

Blow Off Valve (BOV) = vacuum/boost sourced device plumbed between the throttle plate and compressor outlet used to prevent a boosted charge from back pedaling it's way to the exducer of the compressor when the throttle is closed (also known as Back Charge or Negative Charge). BOV's allow the charged flow to be expelled to the open atmosphere (EPA doesn't like this) or be re-circulated back into the inducer side of the compressor. On OE turbo setups this called a re-circulator valve. The re-circulated flow will aid the spool up on street cars that have a problem with turbo lag and it is stealthier because the psst sound of the BOV will not be heard. Without a BOV or re-circulator valve the back pedaling negative charge will cause the thrust bearing of the turbo to fail or it can cause the shaft to break if high boost levels are being used.

Got it now?

Quote from BWX232 :

Parasitic power adders are cool!!




http://www.youtube.com/watch?v ... &search=Prodrive%20P2

The Top Gear guy calls it a waste gate sound.

The guy knows how to drive cars and he's driven a lot of cars... doesn't mean he is the Automotive Bible.

How terrible is the t/c when the guy takes it onto the test track towards the end. The nose almost hits the ground because it's jerking back and forward so hard!

"One reason why it is so fast is because it has something called Anti-lag, which, no one in the world can explain" illepall

http://www.autronic.com/technical_data_files/antilag.pdf
http://www.rallycars.com/Cars/bangbang.html

That's a fantastic example of compressor surge. It's just a shame that he's fed 1000's of people false information because he didn't do a bit of research before hand.

I think you'll find Mr Clarkson does understand anti-lag, but it makes good television to say 'which no one in the world understands'. It's also more amusing, and gives a scope for how complex the systems are in practice, not just in theory.

Mr Clarkson is widely acknowledged to be a very good driver, for a journalist, but that's not exactly saying much. He's good, sure, and he's played in a lot of cars, some fancy others not. But it doesn't mean he has to actually understand much about cars. And he doesn't pretend he understands the maths and theories behind it.

I just think that we hang around car buffs to much, and expect him to be the same. He's a journalist/TV presenter - not the same thing.

He's a fairy to me if he really threw up. I sure hope that was just an act.

Quote :

It's just a shame that he's fed 1000's of people false information because he didn't do a bit of research before hand.

I reckon you'll find the majorioty of people wouldn't really be in the slightest bit bothered by this, they just watch it for light entertainment rather than encyclopaedic stimulation.

Ehh i dunno

Dunno if TopGear is viewed differently over your side of the world then here down-under... but anyone i know that watches TopGear takes it pretty seriously and really enjoys the information and learning about the cars, not just to see the shiny paint and skiddies that they do :hyper: