purerx7

iTrader: (61)

i run the same hks ssqv but with the gold insert, which is even a higher pitched sound than the regular as thats what came with it. I like it much better than the turbo xs rfl i had previously.

RX7LINK

iTrader: (3)

oh cool. thx for info. i've never heard anyone that had the gold insert. It looks almost like the original silver, so i wasn't sure how it changes the sound. good to know. think I'm gonna order one just so i can switch around ... :p

Narfle

iTrader: (16)

Um yeah....That and about 50,000rpm's of momentum on the turbine wheel which will bounce off of a wall of compressed air in front of the turbo snap the shaft in two.

Running without a BOV is like smoking at the gas pump.
You'll get away with it for a while.

Good luck.

Nate8811

Hey, I pmed you bro. Seems like you may wanna check back with us about your setup because every turbo vehicle I have see has a dump valve of some sort. FYI if your turbo locks up its bye bye motor ....thats not just a engine rebuild but a turbo replacement. If your lucky you can rebuild the turbo but I highly doubt that from a turbine lockup. The exhaust gases at first spin the turbine but once after the turbine has been spooled up its spinning crazy rpms which is now producing boost that can suck in small children depending on the size of your turbine at the inlet side.

Q.what spins the turbine wheel is exhaust gas. guess what is missing all together when I close the throttle plates...

A. Its not exhaust gases because when to decelerate what happens? The engine is still running and pumping air or exhaust gases right? When the throttle plate is closed what is venting 10 psi of boost? The only place for it to go is a dump valve system or back into the tubing to the turbine...

I think I know my stuff but if theres details missing please post so I can pass on the lovely information.

http://files.isitaboat.co.uk/big_turbo.jpg

Example of potentially sucking in adults!

willub and company

iTrader: (3)

another thing to consider is whether you are running it with the stock intercooler or a n aftermarket one what has hardpipes. makes a huge difference hard/soft pipes, plastic/metal.

BlueTII

There are several different kits available. I know Apexi, HKS, Blitz and Greddy all make kits that include a mounting bracket and a model specific pipe with mounting flange. The Apexi gives you a little tunability as far as the noise produced as it has a ring that can be rotated with different size holes.
Just shop around there are a million places that sell them on the net.

rexhvn

Can the greddy type S BOV be put in the stock BOV position?

dubulup

dude get off it...your PM was very sincere and I was about to respond, but I come in here I see you bowing up like a f*cking kid on the playground.
Sorry kid, I don't have to check back with anyone about my set-up.

seriously though, have you seen the inside of a turbo? because this is the 3rd post (out of 3 in this thread) you've written in a row with misinformation.

Mahjik

iTrader: (1)

Actually, many factory turbo charged vehicles don't come with BOV's. Granted, they aren't necessarily performance oriented vehicles, but turbo charged none the less. Most purpose built race cars which have turbos do not implement BOV's. However, their reasoning is a little different. They don't use them as that would be another source of failure in their system.

It's a trade-off really as to whether you use one or not. The difference is:

1. With a BOV, you waste air which has already run through the turbo(s). So when the BOV closes, you have to fill that space back up again. Without using a BOV, that air doesn't get wasted and the time it takes to fill the space again and provide FI air to the engine is much less.

2. Without a BOV, when the throttle plates close there is no place for the air to go. So it becomes very disruptive and can shock back down to the compression wheel and either slow it down or attempt to backspin it. This can cause a delay in how fast the compressor wheel spins up again once the throttle plates open up.

I have yet to see any real data that shows the latter actually damaging a turbo. There are many people (mostly Aussie guys) who run the stock twins without BOV's. However, the stock twins don't really last long enough to know if running without a BOV will cause any real problems.

Speedworks

Well...

To add to Majik's post.

positoin of the BOV i s important. As close as possible to the TB is most optimal because when the BOV releases air, the turbocharger will still be spooling (free running) and thus still pushing air into the circuit. The closer the BOV is to the TB the less space the turbocharger needs to fill when the BOV closes again and will be able to get to max boost in the system.
When putting the BOV far from the TB, the turbocharger will need to fill the space behind the BOV upto the TB before it can even build pressure again.


2.when not using a BOV there will be a certain amount of pressure in the air circuit according to how hard you are driving the car. Let's say 10psi.
When releasing the throttle, exhaust gasses will drop and the turbo charger will slow down spooling. when no BOV is in place, the pressure that had been pushed into the circuit (and has nowhere to go because off the closed throttle plates, will move back to the turbocharger and make it slow down even more (compared to if it was running free) (law of the easiest path)or even make it turn backwards. when getting back on the throttle it will take longer/more effort for the turbocharger to get back to speed (or even get back spinning the right direction) before it can build boost again. Making throttle les responsive.

Adding a BOV will relieve air pressure from the system and thus prevents that the boost pressure will work against your system.

a combo of a good BOV, large diameter and the correct position should give you better response.

Mahjik

iTrader: (1)

Think of it as a garden hose. When you turn the valve off on your sprayer nozzle, is there water shooting out at the other end of the hose? Nope. So when you open the valve on the nozzle again, it doesn't have to refill the line, it just starts squirting out.

dubulup

in my real world experience I find the opposite is true. The is never a time where my compressor wheel is spinning backwards. If I'm on boost, usually its a quick shift...No fuel = turbine wheel is slowing down = compressor wheel is slowing down; not pushing as much pressure...so what, my compressor wheel gets hit with a little surge slowing it more...probably around a second before I'm opening the throttle, as soon as there is a crack...that's the path of least resistance and incomes the fuel feeding the turbine once again.

K-Tune

iTrader: (26)

http://www.youtube.com/watch?v=ndRjE0FVttQ

thats a greddy RS.

Triperformance

dubulup I'm new to this turbo stuff and forum but what is the path for the exhaust threw the turbo?

What is the turbo pumping also...I understand that the turbo is spooled by the exhaust gases but after that I'm a little lost lol. I'm just curious and interested in learning!

Speedworks

Dub.. no offence, if you're happy with your setup, that's perfectly fine... I just wanted to indicate the use of a BOV and why it's designed.

a compressor wheel spinning backwards is of course the most extreme situation and will hardly ever happen (unless your REALLY slow at shifting perhaps, nad what's the use of a BOV then huh?:-))

In any case by going of the throttle you create some kind of a 'vacuum' on de exhaust manifold side... slowing the compressor wheels down. making the the engine pick up a little slower. Probably 99% of the owners of turbo cars will hardly ever notice the difference.

And to be very honest... how many people REALLY buy a BOV for it's 'performance' rather than for the cool sound??? not much...

It's not a life change, it's just a detail.

dubulup

The exhaust gas leaves the motor and travels thru the exhaust manifold contacting a turbine wheel (in the turbine housing) then exits the housing into the exhaust...commonly known as the downpipe.

the turbine is connected to compressor wheel by a shaft...the faster the turbine spins the faster the compressor wheel spins. The compressor draws in air and compressing it thru the housing and blows it into the motor (mixed with fuel then ignition yields exhaust gas). More air in = more air out.

RX7LINK

iTrader: (3)

where does the air from the exhaust side go when the turbo surges after throttle close and compressor side exits out the air filter?

wouldn't it suck air in from downpipe and try to push it back into the motor? clashing with your exaust gas exiting from motor, and possibly blow a hole out the side of your exaust manifold gasket?? i've always wondered about that. if anyone can clear that up, thanks in advance.

SLOASFK

iTrader: (5)

no. When the throttle closes, the "waste gate" opens. The waste gate has a function similar to the blow off valve, but instead of being between the turbo and the throttle body, it's located between the engine and the turbo on the exhaust manifold. When you release the throttle, this opens dumping all your exhaust gases either directly into the exhaust(after the turbo) or into the atmosphere.

dubulup

abolutely not...I don't even know where to begin.

your wastegate CLOSES when you are off throttle...why, because the charge pressure is decreasing.

SLOASFK

iTrader: (5)

And this is why I trust others to tell me what my car needs, then pay them to do it. I know enough to know that I know enough to be dangerous.

That last sentence sounds really akward...

willub and company

iTrader: (3)

No, you will have to find a kit that will have an adapter for one of the factory pipes i think. or it might have a pedestal that the valve sits on that plugs into one of the factory hoses.

willub and company

iTrader: (3)

I don't think that a wastegate is like a blow off valve in any way either. more like a pop off valve. it is there to regulate the pressure, not to vent it. why do all these simple threads turn into giant flame fests about who is right and who is wrong?

SLOASFK

iTrader: (5)

I don't know, but I wish they were more civil. There is usually good information to be learned and it all just gets thrown out the window care of other's ego's.

Also, my E-nis is bigger than yours.

BigWillieStyles

Im getting confused but i trust that Mazda technicians knew what they were doing when they had them installed on all FDs. Im sure they werent looking too add more expenses to the FD. And they werent an option.

theorie

iTrader: (31)

dubulup is right. you guys need to read up. BOV's are an optional accessory. maybe if you're pushing like 30lbs of boost you might want one, but for low boost applications they're not really needed. the compressor surge is so minimal you won't even notice.