Yeah, not reducing power from stock, just not providing as much power as optimum. And doing ANY mod to ANY car for the WRONG reasons (i.e. BOV's cos of the noise, or lowering it cos of the looks) is rice in my opinion :P

I've never had a ricing accusation turn into such a good, civilised, interesting conversation though :up:

Quote from tristancliffe :

interesting conversation

Huh? What?

Atmospheric BOV is a bad idea if you're running standard mass airflow sensor. The engine will run rich when the throttle is closed and that can cause backfiring and even stalling because the air that was read by MAS never went in.

In such case it's definitely rice imo

But if you put the MAS downstream of the BOV would that not cure it? Then it would only 'sense' the air going into the engine? I don't really know how they work so it's just speculation.

And far be it from me to try to justify something someone else has called rice

The MAF is not affected by changes in air pressure. Which is precisely WHY it's called a "mass airflow sensor"! It measures mass, pretty much regardless of temperature or pressure.

Besides that, even if that false notion was true, you could use MAP sensors instead anyway and thus would always calculate the correct air/fuel ratio - but MAFs work fine.

Think about where MAFs are located... If there's no air flow there is no fuel, pure & simple.

I've heard this argument before and it makes no sense.

Next.

Quote from tristancliffe :

Yeah, not reducing power from stock,

Ok....

Quote :

just not providing as much power as optimum.

Pardon?

Could you rephrase this paradox you created?

Quote :

And doing ANY mod to ANY car for the WRONG reasons (i.e. BOV's cos of the noise, or lowering it cos of the looks) is rice in my opinion :P

I half agree I guess. We've been there before though so I'll leave it at that. Or will I? Don't you like things that happen to be functional even though they look nice? Are all forms of art rice in your view? All music / art / anything aesthetically oriented, according to what I've heard from you, is therefore pointless and frivolous and rice... Don't you have any fun man? LOL

Quote :

I've never had a ricing accusation turn into such a good, civilised, interesting conversation though :up:

Thanks Tristan although apparantly some people are bored... illepall

Quote from Ball Bearing Turbo :

Could you rephrase this paradox you created?

Well, why fit an open BOV and get "x" spread of power, when you could fit a recirc BOV and get "x + a bit". It's like sacrificing some performance for what in my mind is a silly noise.

Quote :

I half agree I guess. We've been there before though so I'll leave it at that. Or will I? Don't you like things that happen to be functional even though they look nice? Are all forms of art rice in your view? All music / art / anything aesthetically oriented, according to what I've heard from you, is therefore pointless and frivolous and rice... Don't you have any fun man? LOL

Hell yes, looking nice is important. But I'd rather have functionality over looks any day, and I wouldn't sacrifice fuctionality or performance just for aesthetics. Hell, I drive an MX-5 - I know all about sacrificing image for ability But people who lower their car BECAUSE it looks nice, forgetting the pros and cons of the vast majority of bolt on lowering kits, rather than lowering it properly with all that entails for any performance benefits and then being pleased when it happens to look lower annoy me. Ricers don't walk into a shop and say I want to improve the suspension geometry on my car to enhance traction, despite the expense in handling (or whatever that particular component might do). They ask specifically to lower the car by 2 inches, paying little or no regard for what will happen when they do so.

Quote from Ball Bearing Turbo :

I've heard this argument before and it makes no sense.Next.

You probably have because it's on hundreds of pages, here's couple:

http://features.evolutionm.net/article/projectevo/22
http://www.automotiveforums.com/t272165.html
http://www.dsmtuners.com/forum ... 30193&goto=nextoldest
http://www.ls1tech.com/forums/archive/index.php/t-126223

It makes sense to me, there's still airflow when the throttle is closed and the bov is opened.

Quote :

Think about where MAFs are located... If there's no air flow there is no fuel, pure & simple.

Where do you think it's located then? The one I'm talking about is in the airbox or directly after it. ( http://www.evilution.co.uk/info/turbo.jpg )

Quote :

Thanks Tristan although apparantly some people are bored...

If this was directed at me, care to explain?

Quote from vari :

If this was directed at me, care to explain?

No sir, it was I think LOoney who had some sleepy faces posted when Tristan commented on the discussion being interesting hehe

Thank you for joining the discussion, more input is always better!

I will address the rest of the post later I too much work to get done first!

Quote from tristancliffe :

Well, why fit an open BOV and get "x" spread of power, when you could fit a recirc BOV and get "x + a bit". It's like sacrificing some performance for what in my mind is a silly noise.

This is where we still disagree I feel it's the reverse... If you don't want to buy my arguments that's one thing, but if I was wrong why would high performance vehicles not use recirc valves?

Quote :

Hell yes, looking nice is important. But I'd rather have functionality over looks any day, and I wouldn't sacrifice fuctionality or performance just for aesthetics. Hell, I drive an MX-5 - I know all about sacrificing image for ability But people who lower their car BECAUSE it looks nice, forgetting the pros and cons of the vast majority of bolt on lowering kits, rather than lowering it properly with all that entails for any performance benefits and then being pleased when it happens to look lower annoy me. Ricers don't walk into a shop and say I want to improve the suspension geometry on my car to enhance traction, despite the expense in handling (or whatever that particular component might do). They ask specifically to lower the car by 2 inches, paying little or no regard for what will happen when they do so.

This I totally agree with

Quote from Ball Bearing Turbo :

This is where we still disagree I feel it's the reverse... If you don't want to buy my arguments that's one thing, but if I was wrong why would high performance vehicles not use recirc valves?

I guess it depends how high performance you mean. If you have lots of torque (even before the turbo's kick in) then you can run an open BOV because the high torque compensates for the slighly increased time to regain max pressure, and keeping the larger turbines spinning is the main priority. In a lower powered car (again depends on your definition of lower powered, but I'd say less than 300hp) I think the benefits of the recirc valve, for road driving, are greater.

But open or recirc, there's still no need to have a BOV that makes a silly noise. And it's a FACT that people fit BOV's for the noise and not the performance characteristics. Thats why there is an electronic box on sale that plays a recording of "pssssssssshhhhhhhhhhhhhhhhht" when you lift off if you don't even have a turbo. It's also the MAIN reason people ask about BOV's here. Not because it's simulated wrong (or not, I don't know), but because they want a louder noise. Which was, I think, how this topic started.

Yeah one of my friends had a blow off valve and swore by it...tried it for a minute and couldnt stand the sound... Was just too much!

Quote from tristancliffe :

I guess it depends how high performance you mean. If you have lots of torque (even before the turbo's kick in) then you can run an open BOV because the high torque compensates for the slighly increased time to regain max pressure, and keeping the larger turbines spinning is the main priority. In a lower powered car (again depends on your definition of lower powered, but I'd say less than 300hp) I think the benefits of the recirc valve, for road driving, are greater.

This is my main point, I feel that my arguments prove beyond reasonable doubt that recircs actually impede the turbo's inertia more than the atmospheric system, and therefore open BOVs would provide better response in any car... That's my point.... Unless you have the patience to disprove my reasonings from previous posts in some methodical fashion, then we'll probably just have to agree to disagree lol...

Quote :

But open or recirc, there's still no need to have a BOV that makes a silly noise. And it's a FACT that people fit BOV's for the noise and not the performance characteristics. Thats why there is an electronic box on sale that plays a recording of "pssssssssshhhhhhhhhhhhhhhhht" when you lift off if you don't even have a turbo. It's also the MAIN reason people ask about BOV's here. Not because it's simulated wrong (or not, I don't know), but because they want a louder noise. Which was, I think, how this topic started.

Totally agreed.

Really you can purchase a fake BOV? ROFL

yeah, there's these whistle things you can mount in the exhaust to make it sound like a bov

im not too sure about the reasoning behind it, but i know for a fact that atmospheric bov's are more prone to stalling on deceleration (without proper tuning) than a recirc bov.

edit: sorry for bumping the old thread, didnt notice.

First of all, I admit that I have not read the whole thread.
Which means i dont really know what conclusion youve come to.

But on the first page, some guy (tristan??) made a point that the blowoff valve is unnescesery(spelling?), well that is for sure wrong.

Since i'm not very good at English and therefor have a bit of a problem explaining complex things in this language, I'll post a qoute to prove my point:

http://www.newton.dep.anl.gov/askasci/eng99/eng99202.htm

"
The blow-off valve should not be confused with a waste-gate. The waste-gate is a
device that by-passes the turbine wheel of the turbocharger, limiting the
shaft-speed of the turbocharger. Therefore, limiting the boost
(pressure) that the compressor generates and keeping the turbocharger
from over-speeding.

A blow-off valve is mounted in the intake plumbing between the
turbocharger compressor and the throttle plate. The blow-off valve is a
second safety measure against the turbocharger over-boosting and damaging
the engine.

The blow-off valve is more commonly used to keep the turbocharger spinning
when the throttle plate is suddenly closed. When the turbocharger is
generating maximum boost pressure at full throttle and then the throttle
is suddenly closed, compressed air coming from the compressor slams
against the throttle, generating extremely high pressures that travel
backwards to the compressor stopping the compressor from spinning. When
the throttle plate is again opened, the engine must spool the turbocharger
shaft again. The effects of this high pressure can also be very damaging
to the turbocharger.

Brian Wright
Washington University in St. Louis Formula SAE Racing

"

Well that kinda explains the use of a BOV, not saying you must have one, but that
it saves your equipment and reduces the turbolag(spool-up time) since the turbine keeps on spinning.

If you already come to this conclusion I'm sorry to repeat it.
If not, consider yourselfs enlighted!

Indeed you are of course correct, however the debate is basically on which style of BOV is more efficient. Tristan feels that "reciculating" valves are more efficient while I feel that "atmospheric" valves are more efficient.

No matter that you didn't read the thread, I'm still right and Tristan is still wrong.....

:hide:

I say the different types have 'efficiencies' which suit different applications (say road, fast road or race) best.

And BBT knows I'm right anyway, he's just being cheeky

Ive spent the last 20 - 30 mins reading this whole thread but this is what i thought and correct me if im wrong.
I thought that a recirc did was better for day to day driving as it did decrease the time it takes for the turbo to spool but on high performance cars BOV were used as they need to dump pressure so a recirc would hinder the car. Also they use WOT more so the dumping isnt as critical.

I never got to look at my aunts car properly but im sure she had a BOV but it dumped into the exhuast system after the turbo so releasing pressure and not causing the psssssshh noise.
I cant be certain on that as it could of simply been a recirc.

Feel free to flame or correct me as i would like to know.
P.s. - ill try and ask my lecturer at uni if someone would give me the question lol

heh, coming from a Rally background when I think wastegate, I think of a squirrel chirping illepall

Quote from Ball Bearing Turbo :

Indeed you are of course correct, however the debate is basically on which style of BOV is more efficient. Tristan feels that "reciculating" valves are more efficient while I feel that "atmospheric" valves are more efficient.

No matter that you didn't read the thread, I'm still right and Tristan is still wrong.....

:hide:

i'd have to agree with you on the atmospheric type.. and tristan often talks about cars on the road, though in LFS, there are for ex. no streets (etc) to drive on.. if there where, i'd still not agree with him!

everything is and could be rice, right tristan?

Sadly that doesn't make any sense.

Specifically on vehicles with relatively high boost pressures, an atmospheric valve is necessary to alleviate the rapid obliteration of the bearing in the turbocharger (thrust). Going from lower to higher pressure and back again ad naseam does not lower the operating lifetime of an engine. As a matter of fact, any decent quality OEM mill will benefit from some boost, as it actully reduces the intensity of transient loads on the internal components (force is more evenly applied throughout the power stroke).

If you can supply some reasoned argument or at least semi-scientific basis for your argument, I'm all ears... Merely stating "high pressure -> low pressure = bad" is not much of an argument... However, the average ricer bolting some mismatched "stuff" onto his car is reason enough for a lower life expectancy, but not for the reasons you stated

I know Uno's with over 250,000 miles on an engine. And not just one. Oil changes, the odd cambelt etc. Obviously it didn't do many short runs (the 2nd worst thing you can do to an engine) or get revved above 2000rpm with no load (the worst thing you can do). It was just cared for. But they were frequently driven like an Italian engine should be driven

Quote from 02arnoldj :

Can i Just say one thing.

Dump Valves / Blow off Valves may sound nice to Ricers in their Escort Rs Turbos, BUT what they don't (and a lot of other people Dont) Realise is that they reduce your engine life by up to 40,000 Miles

Think about it, Pressure goes in and out and in and out and Nackers the engine Components eventually. Like i saw a Grey Fiat Punto with a Huge exaust that sounded like santa had a Vindaloo on Christmas eve and shat it out through a Trombone, and His Dump Valve sounded like Tony Blair Whispering to Osama Bin Laden in his cave! "PIIIISSSSSShhhhhhhhhT! WEKNOWYOURINTHEEEEEERE"

He obviously doesn't realise his shit piece Fiat Uno 1.4 aint gunna last much longer, Uno's have an engine life of about 60,000 miles, hes only got 20 left after his new Dump valve! Lol
NO OFFENCE TO ANYONE WITH AN UNO! !

can't see anyone agreeing with that..

blow off's are there to prevent the turbo from stalling or stopping (less stress on the engine components..) so how can you claim the oposite?

his car was probably doomed anyway, due to brutal driving and crappy components..

I want a duck call BOV!!!!!
http://www.youtube.com/watch?v ... p;mode=related&search

Your mechanic is an idiot, and knows absolutely nothing there is to know. I am a fully trained mechanic also (and my family owns our own engineering firm, of which I am a director-in-training), and I can tell you two things from that:

1. Fully Trained means you know how to use a spanner
2. It DOES NOT teach you about 'how stuff works'.

The thing about derestricting a moped (which is a completely different kettle aquarium) is that you are making the engine produce more work than the application (and thus the cooling, engine mounts etc) were designed for. On the other hand, the engine was designed originally to produce the unrestricted amount of power, and so would be fine.

Again, your mechanic is an idiot and a fool. Shun him.