max boost good bov
#2
Any stock bov from turbo cars will work. When I first built my turbo setup, I used a 1G DSM bov & recirc'd it... but it wasn't much of a performance part, plus I wanted the PHHHHH... Wooosh! sound, so I got a Turbo XS RFL bov.
Anyway, stock DSM & WRX bov's will work fine for recirc.
Safe boost... There's about 1 billion web pages that talk about "safe boost level" so I would suggest googling it. The gen rule of thumb is nothing more than 10 - 11psi w/o an intercooler. With an IC, but still stock engine, prolly not over 14psi. You can blow a stock headgasket real quick if you don't know what you're doing.
So use the internet & research it. www.google.com works wonders.
Anyway, stock DSM & WRX bov's will work fine for recirc.
Safe boost... There's about 1 billion web pages that talk about "safe boost level" so I would suggest googling it. The gen rule of thumb is nothing more than 10 - 11psi w/o an intercooler. With an IC, but still stock engine, prolly not over 14psi. You can blow a stock headgasket real quick if you don't know what you're doing.
So use the internet & research it. www.google.com works wonders.
#3
guys isn't this one of the biggest z31 forums out there how come no one can answer a question about putting a turbo on a car? And when you do don't tell them to google it there is alot of b/s information on the internet all of you should know that
What the guy said was pretty close to psi you can run i'd stick closer to 9 or so without a intercooler and no more than 15 with the stock engine is strong and can handle alot more psi than that but your fuel system is the big problem take a fuel pump out of a z32 twin turbo or w/e or find a good hi/flow one upgrade your lines and most defently your injectors they are way to small to run anything more than 15 psi on the car you will be running to lean and get pinging (so all together change your whole fuel delivery system) if you want more power.
Now for a bov (do you guys know what they actully do) they release extra presure on the intake side so that the turbo can actully spool faster you do not need a bov (no one contradict me my bro 87 conquest tsi did not have one and i think they knew what they were doing) now it is a good idea to put one in there just so you can get your turbo to spool faster.
I would tell you to actully use and intercooler on your car. I know how arizona heat is and if it is anything like texas it gets way to hott in the middle of summer. The intercooler will help with keeping everything a little cooler at least. You go no intercooler in the middle of summer with 10-11 psi of boost your going to seem a big jump on your temp gauge!
Make sure you get a 02 sensor in there also to tell if your running to lean or rich. To lean is bad pinging and stuff and to rich is bad also with detonation! if your going to do it do it right! thats all i got to say
And guys please help people out im sure there is people out there that know more than i do about this kinda stuff i have only had my z31 for 3 months come on!
What the guy said was pretty close to psi you can run i'd stick closer to 9 or so without a intercooler and no more than 15 with the stock engine is strong and can handle alot more psi than that but your fuel system is the big problem take a fuel pump out of a z32 twin turbo or w/e or find a good hi/flow one upgrade your lines and most defently your injectors they are way to small to run anything more than 15 psi on the car you will be running to lean and get pinging (so all together change your whole fuel delivery system) if you want more power.
Now for a bov (do you guys know what they actully do) they release extra presure on the intake side so that the turbo can actully spool faster you do not need a bov (no one contradict me my bro 87 conquest tsi did not have one and i think they knew what they were doing) now it is a good idea to put one in there just so you can get your turbo to spool faster.
I would tell you to actully use and intercooler on your car. I know how arizona heat is and if it is anything like texas it gets way to hott in the middle of summer. The intercooler will help with keeping everything a little cooler at least. You go no intercooler in the middle of summer with 10-11 psi of boost your going to seem a big jump on your temp gauge!
Make sure you get a 02 sensor in there also to tell if your running to lean or rich. To lean is bad pinging and stuff and to rich is bad also with detonation! if your going to do it do it right! thats all i got to say
And guys please help people out im sure there is people out there that know more than i do about this kinda stuff i have only had my z31 for 3 months come on!
#4
uh hum... lets break this down here:
He wasn't asking about "putting a turbo on his car." That's why we're not talking about that.
Good... but not really what he's asking.
Yeah... so Subaru, Porsche, Nissan, Toyota, Mazda, etc... they're all wrong for putting BOV's on their turbo cars. Do YOU know what the purpose of the BOV is?
yep... but he said no intercooler
um... I think the Z31 has an O2 (not zero two) sensor already. He would benefit from an AIR FUEL METER.
So let's not serve BS to those that ask questions... ok?
Originally Posted by machsound
guys isn't this one of the biggest z31 forums out there how come no one can answer a question about putting a turbo on a car? And when you do don't tell them to google it there is alot of b/s information on the internet all of you should know that
Originally Posted by machsound
What the guy said was pretty close to psi you can run i'd stick closer to 9 or so without a intercooler and no more than 15 with the stock engine is strong and can handle alot more psi than that but your fuel system is the big problem take a fuel pump out of a z32 twin turbo or w/e or find a good hi/flow one upgrade your lines and most defently your injectors they are way to small to run anything more than 15 psi on the car you will be running to lean and get pinging (so all together change your whole fuel delivery system) if you want more power.
Originally Posted by machsound
Now for a bov (do you guys know what they actully do) they release extra presure on the intake side so that the turbo can actully spool faster you do not need a bov (no one contradict me my bro 87 conquest tsi did not have one and i think they knew what they were doing) now it is a good idea to put one in there just so you can get your turbo to spool faster.
Originally Posted by machsound
I would tell you to actully use and intercooler on your car. I know how arizona heat is and if it is anything like texas it gets way to hott in the middle of summer. The intercooler will help with keeping everything a little cooler at least. You go no intercooler in the middle of summer with 10-11 psi of boost your going to seem a big jump on your temp gauge!
Originally Posted by machsound
Make sure you get a 02 sensor in there also to tell if your running to lean or rich. To lean is bad pinging and stuff and to rich is bad also with detonation! if your going to do it do it right! thats all i got to say
Originally Posted by machsound
And guys please help people out im sure there is people out there that know more than i do about this kinda stuff i have only had my z31 for 3 months come on!
#5
Also on the BOV, it's not only meant to help the turbo spool quicker. A more important function of the BOV is to protect the turbo from compressor surge. Compressor surge can ruin a turbo. It can destroy your thrust bearing and, if the turbo is spinning fast enough and pushing enough air, even damage the compressor wheel. I would recommend a BOV for any turbo charged car. Is it needed, no. But its a damn good idea.
#6
attack of the know it all noobs . i like the "oh, this guy i know has a conquest so i know what im talking about". haha. welcome to zdriver. it seems there are a few things you need to learn about how this place works. we will always suggest that people search for info first. get the info, then come here and ask for clarfication. this keeps us from answering the same questions over and over. stick around, we will be glad to help you with anything, and appreciate your input. but we ask that you help yourself before we help you.
#7
Originally Posted by machsound
guys isn't this one of the biggest z31 forums out there how come no one can answer a question about putting a turbo on a car? And when you do don't tell them to google it there is alot of b/s information on the internet all of you should know that
What the guy said was pretty close to psi you can run i'd stick closer to 9 or so without a intercooler and no more than 15 with the stock engine is strong and can handle alot more psi than that but your fuel system is the big problem take a fuel pump out of a z32 twin turbo or w/e or find a good hi/flow one upgrade your lines and most defently your injectors they are way to small to run anything more than 15 psi on the car you will be running to lean and get pinging (so all together change your whole fuel delivery system) if you want more power.
Now for a bov (do you guys know what they actully do) they release extra presure on the intake side so that the turbo can actully spool faster you do not need a bov (no one contradict me my bro 87 conquest tsi did not have one and i think they knew what they were doing) now it is a good idea to put one in there just so you can get your turbo to spool faster.
I would tell you to actully use and intercooler on your car. I know how arizona heat is and if it is anything like texas it gets way to hott in the middle of summer. The intercooler will help with keeping everything a little cooler at least. You go no intercooler in the middle of summer with 10-11 psi of boost your going to seem a big jump on your temp gauge!
Make sure you get a 02 sensor in there also to tell if your running to lean or rich. To lean is bad pinging and stuff and to rich is bad also with detonation! if your going to do it do it right! thats all i got to say
And guys please help people out im sure there is people out there that know more than i do about this kinda stuff i have only had my z31 for 3 months come on!
What the guy said was pretty close to psi you can run i'd stick closer to 9 or so without a intercooler and no more than 15 with the stock engine is strong and can handle alot more psi than that but your fuel system is the big problem take a fuel pump out of a z32 twin turbo or w/e or find a good hi/flow one upgrade your lines and most defently your injectors they are way to small to run anything more than 15 psi on the car you will be running to lean and get pinging (so all together change your whole fuel delivery system) if you want more power.
Now for a bov (do you guys know what they actully do) they release extra presure on the intake side so that the turbo can actully spool faster you do not need a bov (no one contradict me my bro 87 conquest tsi did not have one and i think they knew what they were doing) now it is a good idea to put one in there just so you can get your turbo to spool faster.
I would tell you to actully use and intercooler on your car. I know how arizona heat is and if it is anything like texas it gets way to hott in the middle of summer. The intercooler will help with keeping everything a little cooler at least. You go no intercooler in the middle of summer with 10-11 psi of boost your going to seem a big jump on your temp gauge!
Make sure you get a 02 sensor in there also to tell if your running to lean or rich. To lean is bad pinging and stuff and to rich is bad also with detonation! if your going to do it do it right! thats all i got to say
And guys please help people out im sure there is people out there that know more than i do about this kinda stuff i have only had my z31 for 3 months come on!
How does a BOV help the turbo spool quicker? A BOV vents charged air to atmosphere when the throttle plate is closed during shifts. A recirc valve places the charge air back in the intake where it is used. And I've run 11 or 12 psi in Texas summers without an ic and had no overheating issues at all.
Now I remember why I stopped posting here
#9
Originally Posted by nismo619
u know machsounds does have a good idea.. maybe there is a few GROUCHY people in this wed site...
#10
Nismopick i have let it go.. but on the good side of things nismo pick i have learned alot for your wrods of wizdon.. unlike other moderators lol its cool between me nad u nismopick.. no hard feelings..
#11
Well first off, I dont think Nismopick is a moderator
And to ZenArcher: Yes, a BOV DOES help the turbo spool faster between shifts. By venting the pressure to atmosphere instead of letting it slam back into the compressor wheel and slowing it or even stalling it. So by doing it that it allows the compressor wheel to continue to spin freely which keeps the wheel speed up which means the turbo is ready to go back on boost which translates to less lag between shifts
Is it more effective then a recirc. BOV? No. But it's still more effective then not having a BOV.
And to ZenArcher: Yes, a BOV DOES help the turbo spool faster between shifts. By venting the pressure to atmosphere instead of letting it slam back into the compressor wheel and slowing it or even stalling it. So by doing it that it allows the compressor wheel to continue to spin freely which keeps the wheel speed up which means the turbo is ready to go back on boost which translates to less lag between shifts
Is it more effective then a recirc. BOV? No. But it's still more effective then not having a BOV.
#12
"And to ZenArcher: Yes, a BOV DOES help the turbo spool faster between shifts. By venting the pressure to atmosphere instead of letting it slam back into the compressor wheel and slowing it or even stalling it. So by doing it that it allows the compressor wheel to continue to spin freely which keeps the wheel speed up which means the turbo is ready to go back on boost which translates to less lag between shifts"
That does not equate to spooling faster...
That does not equate to spooling faster...
#13
Originally Posted by ZenArcher
"And to ZenArcher: Yes, a BOV DOES help the turbo spool faster between shifts. By venting the pressure to atmosphere instead of letting it slam back into the compressor wheel and slowing it or even stalling it. So by doing it that it allows the compressor wheel to continue to spin freely which keeps the wheel speed up which means the turbo is ready to go back on boost which translates to less lag between shifts"
That does not equate to spooling faster...
That does not equate to spooling faster...
Anyway... Whether you like it or not, a BOV keeps the compressor spinning faster between shifts & when letting off the throttle quickly.
On a side note, it doesn't make the turbo spool faster from a dead stop & idling... ONLY BETWEEN SHIFTS
#14
I doubt I'll be quoting people here in the future but thanks for the tip. A BOV does not make a turbo spool faster. If you guys want to think that it does that's fine by me but it still won't be true. If you go back and read my post carefully I explained exactly what a BOV/recirc valve does. Of course in the process of venting the charge air it prevents the charge air from going backwards and slowing the compressor wheel. That's it's primary function... Did I really need to explain that part to anyone? No, don't answer that. Anyways, some things that actually do make a turbo spool "faster":
A larger diameter exhaust
a smaller exhaust housing a/r
an external wastegate
A larger diameter exhaust
a smaller exhaust housing a/r
an external wastegate
#15
So in your world of "I don't need to follow the laws of physics" you think that if there are two identical turbocharged cars, EXCEPT one has a BOV, and the other doesn't, there will be no difference in turbo lag / spool when driving? IS ANYONE ELSE READING THESE POSTS? I FEEL LIKE BANGING MY HEAD AGAINST THE WALL!
#16
Maybe banging your head against the wall would shake a few synapses loose and improve your reading and comprehension skills Sorry to barge in after all this time and inject some reality and precision into the place. Even zcar.com isn't this bad. I'll be off now. Carry on boys...
#17
Originally Posted by ZenArcher
Maybe banging your head against the wall would shake a few synapses loose and improve your reading and comprehension skills Sorry to barge in after all this time and inject some reality and precision into the place. Even zcar.com isn't this bad. I'll be off now. Carry on boys...
#19
I hate BOVs. I think they're ricer crap. Just my opinion. I personally prefer the full throttle shifts over obnoxious blow off valves.
BTW: A turbo will still lose a lot of it's RPM when shifting no matter what you do.
On the same engine, one with a BOV and one without, the turbo will still provide near enough the same boost levels by the time you start using the next gear.
Laws of physics still apply here people. What a BOV does is prevent compressor surge. But it does nothing for the turbine side. Don't forget, the turbine side is what drives the compressor side. And the exhaust is what drives the turbine. And the intake is what provides air for the exhaust. And if there is no air in the engine (you just slammed the throttle shut), you have no exhaust.
So.... If you no longer have RPMs in the engine, what is keeping the turbine side spooling?
Now, back to the original question:
I can't help you as I am against BOVs.
This falls under stupid question number 25 on my list of commonly asked stupid questions. So, I'm guessing you're new to turbos and probably cars in general, right? Don't worry, you aren't the first to ask this question and you won't be the last. Now, the answer is...
Eleventy billion. Seriously. Depends on (but not limited to):
- engine condition - includes:
- - pistons
- - rods
- - valves
- - spark plugs
- - wires
- - fuel injectors
- - fuel pressure
- - fuel pump
- - etc
- octane fuel used
- air density
- temperature (air and engine)
Basically, you turn it up until you get detonation. Then, you either retard the timing a little or turn the boost down a PSI or two.
BTW: A turbo will still lose a lot of it's RPM when shifting no matter what you do.
On the same engine, one with a BOV and one without, the turbo will still provide near enough the same boost levels by the time you start using the next gear.
Laws of physics still apply here people. What a BOV does is prevent compressor surge. But it does nothing for the turbine side. Don't forget, the turbine side is what drives the compressor side. And the exhaust is what drives the turbine. And the intake is what provides air for the exhaust. And if there is no air in the engine (you just slammed the throttle shut), you have no exhaust.
So.... If you no longer have RPMs in the engine, what is keeping the turbine side spooling?
Now, back to the original question:
Originally Posted by 300_240
What is a good bov to use that I can resurculate?
Originally Posted by 300_240
What is a good safe boost I can run with 88,000 mile engine,with 3'' mand exaust and k&n intake,no intercooler,in texas heat on 93 octane?n an 86 300zx]
Eleventy billion. Seriously. Depends on (but not limited to):
- engine condition - includes:
- - pistons
- - rods
- - valves
- - spark plugs
- - wires
- - fuel injectors
- - fuel pressure
- - fuel pump
- - etc
- octane fuel used
- air density
- temperature (air and engine)
Basically, you turn it up until you get detonation. Then, you either retard the timing a little or turn the boost down a PSI or two.
#20
Originally Posted by AZ-ZBum
I hate BOVs. I think they're ricer crap. Just my opinion. I personally prefer the full throttle shifts over obnoxious blow off valves.
BTW: A turbo will still lose a lot of it's RPM when shifting no matter what you do.
On the same engine, one with a BOV and one without, the turbo will still provide near enough the same boost levels by the time you start using the next gear.
Laws of physics still apply here people. What a BOV does is prevent compressor surge. But it does nothing for the turbine side. Don't forget, the turbine side is what drives the compressor side. And the exhaust is what drives the turbine. And the intake is what provides air for the exhaust. And if there is no air in the engine (you just slammed the throttle shut), you have no exhaust.
So.... If you no longer have RPMs in the engine, what is keeping the turbine side spooling?
BTW: A turbo will still lose a lot of it's RPM when shifting no matter what you do.
On the same engine, one with a BOV and one without, the turbo will still provide near enough the same boost levels by the time you start using the next gear.
Laws of physics still apply here people. What a BOV does is prevent compressor surge. But it does nothing for the turbine side. Don't forget, the turbine side is what drives the compressor side. And the exhaust is what drives the turbine. And the intake is what provides air for the exhaust. And if there is no air in the engine (you just slammed the throttle shut), you have no exhaust.
So.... If you no longer have RPMs in the engine, what is keeping the turbine side spooling?
I'm a recirc. type of guy myself. I'm not a big fan of the whistling or chirping blow off valves that vent.
Last edited by jfairladyz; 04-25-2006 at 06:14 PM.
#21
and keeping the throttle open during shifts does much more by still keeping the turbo spinning even faster.
No, you no longer have a huge pressure on the compressor, but you do still have a huge vacuum on the turbine that will slow it down almost as fast.
So no matter what way you look at it, the turbo is still spinning much much slower than it was. How much of a difference? Not really enough to make a difference in respool time.
No, you no longer have a huge pressure on the compressor, but you do still have a huge vacuum on the turbine that will slow it down almost as fast.
So no matter what way you look at it, the turbo is still spinning much much slower than it was. How much of a difference? Not really enough to make a difference in respool time.
#22
True keeping on it is more effective. But it's still not always practical.
But again, when you make your point about the turbo slowing down you're still neglecting that the surge air just slows the compressor down more then it would be if that air wasn't returning to the comressor through the outlet. Sure letting off is going to slow the turbo. But letting that surge air hit the compressor wheel is just going to slow it even more. That is my point. By venting or recirculating that air you have fewer forces working to slow the wheel. Therefore the wheel speeds of the turbo will still be higher with a BOV then if you were running without one (and letting the throttle close between shifts).
But again, when you make your point about the turbo slowing down you're still neglecting that the surge air just slows the compressor down more then it would be if that air wasn't returning to the comressor through the outlet. Sure letting off is going to slow the turbo. But letting that surge air hit the compressor wheel is just going to slow it even more. That is my point. By venting or recirculating that air you have fewer forces working to slow the wheel. Therefore the wheel speeds of the turbo will still be higher with a BOV then if you were running without one (and letting the throttle close between shifts).
#23
No, I'm not neglecting it. And I know it's called compressor stall for a reason. It's because it drops to near 0 before picking back up a little. But even with a BOV, it will still drop to less than probably 10,000 rpms. But in the grand scheme of things, when turbos spin at 100,000+ rpms, the difference with and without is virtually nil.
#24
Thats like saying the difference in your car getting to 100mph from a stop isn't going to be much different then getting there from 10mph. Again, it's all about momentum. It takes more effort to move an object at rest then it does to move an object that's already going. And recirculating just makes it that much more effective. And of course we'd all like our thrust bearings to last a really long time too. At stock boost levels it's not really that big of a deal. But when you start pushing more pressure then a BOV is a very good idea, especially if it's recirculated like it should be. The noise is ricey, but the part itself is far from it.
#25
Originally Posted by jfairladyz
Thats like saying the difference in your car getting to 100mph from a stop isn't going to be much different then getting there from 10mph.
Originally Posted by jfairladyz
Again, it's all about momentum.
Originally Posted by jfairladyz
It takes more effort to move an object at rest then it does to move an object that's already going.
Originally Posted by jfairladyz
And recirculating just makes it that much more effective.
Originally Posted by jfairladyz
And of course we'd all like our thrust bearings to last a really long time too.
Originally Posted by jfairladyz
At stock boost levels it's not really that big of a deal. But when you start pushing more pressure then a BOV is a very good idea, especially if it's recirculated like it should be. The noise is ricey, but the part itself is far from it.