My car runs with negative pressure.

I bet you know what I mean by my car running on about 14psi! Because your smart, right?

Of course

But I'd expect it to run at a bit less that 14 personally. Depends on revs and throttle I guess... Maybe I should get one them absolute gauges, I've only got a cheap gauge gauge.

On mount Everest your car would be running on 5psi!

EDIT: If they built a racetrack on mount everest, you would have to instal like a 9psi supercharger just to get equal performance as NA..

ok mate nice try, but answer is no your wrong, yes u can use plumbed back valve dumps into intake pipe off your turbo, usaly its done on cars which have sensitive air sensors running through your vaccum line which can lower your idle when coming off boost, i.e skylines rb20det and 25det can** have this problem, i had this problem on my rb20det gtst but put up with it cause bov sounded nutz, no u dont loose power cause u only dump when throttle off, nub lol

I don't see the problem with someone wanting a bov-sound they like in LFS, even if there are some people not liking these sounds AT ALL.. not mentioning any names, but tristan does come to mind!

And for you people that claim that a bov makes your car lose power, well, it's not like that in LFS ffs! so why bother coming with that argument!


personally i'd like the bov in LFS to release a bit earlier, cause it's i bit slow to my liking.. but i like that noise the turbo makes when there's backsurge, that chatter/laughing noise, hehe! at least a bit of it.. sound is more than half the experience people!

Quote from lrdbsi :

ok mate nice try, but answer is no your wrong, yes u can use plumbed back valve dumps into intake pipe off your turbo, usaly its done on cars which have sensitive air sensors running through your vaccum line which can lower your idle when coming off boost, i.e skylines rb20det and 25det can** have this problem, i had this problem on my rb20det gtst but put up with it cause bov sounded nutz, no u dont loose power cause u only dump when throttle off, nub lol

If you have a BOV which sends the power back to your intake, it will gain pressure a lot faster than with a regular BOV, for instance your car would run better without that HKS BOV of urs. If you have for instance a bov like yours you would have to have a highly tuned car to take advantage of it becouse blow off valves really are developed to let out the pressure so that your engine doesnt blow itself to smitherins hehe

Btw Lrdbsi, you should think more about how you treat people in here, wether theyre right or wrong, stop acting like an *ssh*le...

I cannot and have never ever heard a blow off valve in ANY car in LFS.. Please tell me a car that you should be able to hear it on.

XR GT Turbo
RB4
FXO Turbo
FXO GTR
MRT5 (I think it makes the sound)

You yanks crack me up, bloody blow off valve over here in the uk we call them waste gates, also to release back pressure in the turbos we use dump valves what is a single loud hiss. wastes gates are the chirping sound.

we call them waste gates too

isn't there a differense between wastegates and bovs? wastegates releases pressure to prevent overboost, and bovs releases when you go off throttle (for ex. when shifting?) and prevents the turbo from stopping?? correct me if i'm wrong, just wanted to correct these people!

Quote from keltern :

isn't there a differense between wastegates and bovs? wastegates releases pressure to prevent overboost, and bovs releases when you go off throttle (for ex. when shifting?) and prevents the turbo from stopping?? correct me if i'm wrong, just wanted to correct these people!

Yeah it does it off throttle for the exact same reason... never heard of a separate valve other than the waste gate/blow off valve.

I still have never freaking heard it in LFS- is there a mod that makes it a lot louder? I tried one of those mods from the files forum and still cannot hear it one little bit.

i can hear the bov in lfs. but i've installed one of the ones posted here so it is a bit louder than the defualt one. I'm sure someone here must know how to increase/decrease the sound of the bov?

Well I bet you could just boost the volume of the wav file or whatever it is.. in a sound editor.. but not sure what what the deal is with the files LFS uses.

lol, think i've read one too many bullshit comments on what and what isn't a bov!

sorry, i stand corrected, stupid little me..illepall

Quote :

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

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


guess it is different...

hi where do you put this file ?

"Your LFS folder"/data/snd and theres a file called "DumpValve.raw", which you can replace with this one.

But remember to backup the original file.

Quote from lrdbsi :

blah blah same old blah meh,
http://files.filefront.com/Dum ... /;5094592;;/fileinfo.html
like it, hate it i dnt care!

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

Quote from tristancliffe :

This stalls the turbine and stops it pretty quickly. It can also SERIOUSLY damage your turbo.

It doesn't actually stop the compressor from spinning completely, it only slows it down. If it stopped the compressor, then the sound wouldn't be happening. The sound is obviously from the air being fed back through the front of the turbo and is the sound of the impeller fins slicing through that air.

As far as damage from not running a BOV, 6 of one, half a dozen of the other. I know people running drag cars with no BOV and the turbo creating in excess of 20-25 pounds of boost, and these cars have been running for years in that configuration with no damage to the turbo. Damage to the turbo from compressor surge will depend on what turbo you're using (quality of the bearings/shaft) and how much boost you're running (how much air is trying to get squeezed back through?)

Bad idea to start calling a BOV a Wastegate, you will only confuse yourself when the time comes to reading about them. Put simply, a wastegate bleeds off excess exhaust gasses once a certain amount of pressure is reached (how hard is your wastegate spring?) it does this so the turbo doesn't keep spooling harder and keep creating more pressure and eventually ramming 50 pounds into your stock SR20 engine... a little exagurated for the factory T25's but you get the point.

A BOV is integrated into cars for the following reasons:

1) A "safety" measure against damaging the turbo from compressor surge.
2) To stop compressor surge on factory cars and to quieten things down (when plumbed back into the intake). Can you imagine the look on the owner of a brand new Saab if his car was making those noises!? lol
3) To stop air returning back through the compressor causing disturbance in the flow of air, resulting in the turbo having fight through this pressure when it comes time to spool. In other words, reduce lag.

Quote from wheel4hummer :

I bet you know what I mean by my car running on about 14psi! Because your smart, right?

Sure, if you're talking vacuum?

Quote from Shinanigans :

It doesn't actually stop the compressor from spinning completely, it only slows it down. If it stopped the compressor, then the sound wouldn't be happening. The sound is obviously from the air being fed back through the front of the turbo and is the sound of the impeller fins slicing through that air.[quote]

I said that without a BOV it'll stall the turbo - without a BOV there is no (or very little) noise.

[quote=Shinanigans]As far as damage from not running a BOV, 6 of one, half a dozen of the other. I know people running drag cars with no BOV and the turbo creating in excess of 20-25 pounds of boost, and these cars have been running for years in that configuration with no damage to the turbo.

And drag cars are designed to work at full load, not retain drivability at varying throttle openings, so not really relevent to this discussion.

[quote=Shinanigans]Bad idea to start calling a BOV a Wastegate, you will only confuse yourself when the time comes to reading about them. Put simply, a wastegate bleeds off excess exhaust gasses once a certain amount of pressure is reached (how hard is your wastegate spring?) it does this so the turbo doesn't keep spooling harder and keep creating more pressure and eventually ramming 50 pounds into your stock SR20 engine... a little exagurated for the factor T25's but you get the point.[/quote]Yes, we'd already said that a BOV isn't a wastegate. Did you read the thread?

[quote=Shinanigans]Sure, if you're talking vacuum? [/quote]
So you didn't get this then, lol.

All i can say is "LOL"

Just a few things i think should be cleared up so people who read this thread don't leave this thread with less intelligence (then it's already caused).

1. The turbo "wheel" doesn't get oiled, the shaft does.

2. LOL @ drilling sump for oil to the turbo. Can you tell me why you can buy magnetic sump plugs?

3.

Quote :

a compressor wheel with sevral spindals on it which do the magic

I think you mean impeller blades...

Quote from lrdbsi :

ok heres the thing it doesnt *stall* the compressor wheel it STOPS IT
then it SPINS IT BACK WARD , my mechanic told me is compressor wheel back surge, (boost surges back through compressor) and dumps it out the intake of the turbo ,dont come here saying your name is right just cause u think it should be called that,

anyway im sick of know it all turbo fags like u , u knew wat i meant instead u try to information arguing which is pathetic and immature, grow up

Wrong.

It doesn't stop the wheel, infact it barely even slows the wheel. Considering you go on so much about how you know everything about turbos, why don't you stick your head in an engine bay with a turbo and watch what the compressor wheel does... illepall

The "choof choof choof" sound is generated by the air coming back through the turbo (technically called "Compressor Surge". The sound is the compressor side impeller fins slicing through the returning air.

The reason your/mechanics theory is wrong is because the "choof choof choof" sound lowers in pitch. This is because the impeller is slowing down. It makes no sense with you saying that the compressor wheel stops... how can something that is not moving make sound?

Ok, well i don't really want to get into an argument with you because i'm only new to the forum, but i'm happy to discuss cars with you in a friendly way

Quote :

I said that without a BOV it'll stall the turbo - without a BOV there is no (or very little) noise.

Running no BOV won't stall the turbo, it will slow it down. I explained this in another thread here:

http://www.lfsforum.net/showthread.php?p=139425#post139425

Quote :

And drag cars are designed to work at full load, not retain drivability at varying throttle openings, so not really relevent to this discussion.

Not meaning to patronise you, but have you been to drag races? Lots of vented valves going off at a night at the drags here in Aus, mainly during tyre warm up. My point was more towards the amount of boost that some of the cars are running and that if running no BOV was going to damage your turbo, certainly you'd hear about it at the drags. Secondly, which i should've mentioned in the post, a lot of the cars that i'm referring to are street cars which are driven home. Hardly any of the cars on a Wednesday night meet are trailered to and from the strip. So it has huge relevance. They run huge amounts of boost, no BOV's and are street driven cars.

Personally, when i upgrade to a Trust TD06 for my FC, i don't plan on running any BOV because i trust the build quality and relability of a Trust turbo will negate the need for a BOV to prolong the life of it. But i still run the factory Bosch unit with the standard turbo for now.

Quote :

Yes, we'd already said that a BOV isn't a wastegate. Did you read the thread?

Yeah i did....Was just saying it in my own way just incase it made more sense then other peoples explanations.... Sorry

Quote :

My car runs with negative pressure.

Quote :

I bet you know what I mean by my car running on about 14psi! Because your smart, right?

Quote :

Of course

But I'd expect it to run at a bit less that 14 personally. Depends on revs and throttle I guess.

Quote :

Sure, if you're talking vacuum?

Quote :

So you didn't get this then, lol.

Looks to me as though you were discussing how non turbo cars run 14 pounds vacuum (absolute/atmospheric pressure). I say "vacuum" because the opposite of pressure is vacuum... but if you say i'm wrong about your discussion, then so be it.

Cheers.