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are wastegates manditory? what do wastegates do on a turbo system??? do i need one?
Turbo Questions
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yep
im no turbolater mechanic but i would say they are mandatory!
The wastegate is operated by an air actuator. The actuator gets its air from the discharge side of the turbocharger. The waste gate has a spring and a diaphragm - the spring acts to keep the waste gate closed and the diaphragm acts with pressure to open the waste gate. The waste gate itself is simply a round hole with a cover that allows exhaust to bypass the turbine wheel when it is open. The actuator actually has a range of pressure where it starts to open, and will be fully open at a higher pressure. You are not likely to see or feel its effects, except that it limits the maximum boost you can get out of the turbo. As boost pressure increases, the air pressure overcomes a spring pressure within the actuator, and via an adjustable rod, the wastegate begins to open. When the wastegate opens, exhaust gasses that have been driving the turbine wheel, are diverted around the turbine, allowing it to slow down. The transition is relatively subtle, so one doesn't really feel it.
If the actuator fails to open the wastegate, the turbo will continue to boost, and the pressure it achieves will exceed what the engine can use. The fuel system has a failsafe built into it that cuts the ground signal to the fuel pump relay during an overboost. The cause of the overboost is usually caused by the actuator hose failing.
There is a difference between what your gage reads and what the waste gate sees for pressure. The dash gage is connected to the engine side of the throtle body. That means that it reads the pressure/vacuum in the intake manifold. When the throttle is wide open, it will read pretty much want the turbo is putting out, however at any other position, it will read a lower pressure. The waste gate sees the pressure at the turbo outlet (for non intercooled cars) or the outlet of the intercooler for intercooled cars
are we allowed to talk about turbochargers on this board?
:mwink:
im no turbolater mechanic but i would say they are mandatory!
The wastegate is operated by an air actuator. The actuator gets its air from the discharge side of the turbocharger. The waste gate has a spring and a diaphragm - the spring acts to keep the waste gate closed and the diaphragm acts with pressure to open the waste gate. The waste gate itself is simply a round hole with a cover that allows exhaust to bypass the turbine wheel when it is open. The actuator actually has a range of pressure where it starts to open, and will be fully open at a higher pressure. You are not likely to see or feel its effects, except that it limits the maximum boost you can get out of the turbo. As boost pressure increases, the air pressure overcomes a spring pressure within the actuator, and via an adjustable rod, the wastegate begins to open. When the wastegate opens, exhaust gasses that have been driving the turbine wheel, are diverted around the turbine, allowing it to slow down. The transition is relatively subtle, so one doesn't really feel it.
If the actuator fails to open the wastegate, the turbo will continue to boost, and the pressure it achieves will exceed what the engine can use. The fuel system has a failsafe built into it that cuts the ground signal to the fuel pump relay during an overboost. The cause of the overboost is usually caused by the actuator hose failing.
There is a difference between what your gage reads and what the waste gate sees for pressure. The dash gage is connected to the engine side of the throtle body. That means that it reads the pressure/vacuum in the intake manifold. When the throttle is wide open, it will read pretty much want the turbo is putting out, however at any other position, it will read a lower pressure. The waste gate sees the pressure at the turbo outlet (for non intercooled cars) or the outlet of the intercooler for intercooled cars
are we allowed to talk about turbochargers on this board?
:mwink:
Yes, you need one. Most engines, unless specifically built for turbo use can only take about 5-7 psi of boost. A turbo suitably matched to your engine will likely be capable of producing up to 20 psi or so. If you tried running anything close to that you'd destroy your engine very quickly. The wastegate controls the boost by letting excess exhaust "bypass" the turbo once you have reached the maximum desired boost psi. Most factory installed turbos have the wastegates preset at whatever they determined was allowable. Aftermarket turbos often have adjustable wastegates so the customer can dial in what he needs. Most turbos have the wastegates built into( or onto) them. Some applications use a "remote" wastegate that hooks into the exhaust system elsewhere. Most performance guys don't seem to care for the remote wastegate setup.
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I've heard that the T04 turbo setup works on smallblocks...what do i need to do to the turbo before it can work on my motor? or cAN I use it just the way it came off of the other motor? do i need a new BIGGER compressor side? because i found one from a 79 regal, and want to know before i start doing it. thanks
Since a turbo uses exhaust gas to push in intake air I don't think your going to get much improvment from just changing the compressor side.
Think of it this way. More exhaust gas means more fresh air. So a larger engine really only means a faster spinning turbo.
My honest guess is that turbos have quite a bit of forgiveness in what engine sizes each with work with. Your best bet is to find out if the turbo can take that much exhaust pressure and if anyone else has used one on that motor before. If not exactly that turbo then see if what they used is a close match to what you have. Get the exact spects on your turbo from the manufacturer.
You shouldn't have to change anything in a turbo except MAYBE a few seals and bearings to bring it up to snuff and maybe a wastegate spring to change pressure.
Think of it this way. More exhaust gas means more fresh air. So a larger engine really only means a faster spinning turbo.
My honest guess is that turbos have quite a bit of forgiveness in what engine sizes each with work with. Your best bet is to find out if the turbo can take that much exhaust pressure and if anyone else has used one on that motor before. If not exactly that turbo then see if what they used is a close match to what you have. Get the exact spects on your turbo from the manufacturer.
You shouldn't have to change anything in a turbo except MAYBE a few seals and bearings to bring it up to snuff and maybe a wastegate spring to change pressure.
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If you were to use a bigger discharge then a smaller exhaust you would see the most boost. My guess is that you are asking so if you want alot of boost at a low RPM go with a turbonetics T3/T4 hybrid (T3 style exhaust with a T4 style discarge these work great and use the T3 flange) but a T3 would more then likely make you happy.
Eric
Eric
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should i buy it aftermarket, or is there a vehicle that has one that mi might be able to search for???
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Here are the options, for a Hybrid look in junk yard(s) for a wrecked riced up import (don't just look for wings look under everyhood- they make sleepers too) and look for turbo's, check their numbers and bring them back also make sure they spin freely. If you can't find any go aftermarket (ebay is what I perfer) but they can go from 400 and up. If you want a T3 series (NO hybrid) you can again look for the wrecked riced up imports (don't just look for wings look under everyhood- they make sleepers too). These are about 300 and up for just the turbo.
Remember Wastegate, manifold, blow off (if manual trans), watch your compression (build your motor to handle boost, you can run 11lbs on an 8:1 on pump gas, but if you try to run 11lbs on an 11:1 motor kiss it goodbye). These are all ontop of the turbo(s) price.
Eric
Remember Wastegate, manifold, blow off (if manual trans), watch your compression (build your motor to handle boost, you can run 11lbs on an 8:1 on pump gas, but if you try to run 11lbs on an 11:1 motor kiss it goodbye). These are all ontop of the turbo(s) price.
Eric
whats up fellas. i may be a youngin but i right now own a hopped up turbo'd rice bucket. the key to going turbo on just about anything is keeping fuel and timing under control. compression does play a huge factor in boost allowance, but timing and fuel are actually the most important. having cast rods and pistons can take anywhere from 0-14psi or 1 bar of boost but needs to be matched to appropriate fuel and timing. detonation is usually the key factor that destroys a turbo'd motor which i havent had to worry about yet. on my car as of now i run 10.2:1 and am sitting on 8psi without any problems. my max timing is at 22 degrees. so when going for a turbo on your motor just remember if you want to make huge reliable power go with forged internals, if you just want some extra grunt stock internals will work with the right fuel and spark. for a small block i would suggest going with a t04r or to4s turbo and mate it with an external wastegate so as to not to have to worry about boost spiking (somewhat common on internal wastegates on v8's). having fuel injection will help a ton in this area but it can be done with a carb just as easily.
oh also to answer some other questions. having a larger compressor side (a hybrid) will increase efficiency, aka lower boost that flows more lbs of air will run better along with be safer...the wastegate will compensate so to not cause problems. running two (2) turbo's from a grand national (one on each bank of cylendars) would allow you to run stock internals on 7psi and not have an abundance of pipes all over the engine bay (well less than what you would have with only 1 turbo). just make sure to get an intercooler since heat=detonation it will greatly reduce the chances of popping the motor
oh also to answer some other questions. having a larger compressor side (a hybrid) will increase efficiency, aka lower boost that flows more lbs of air will run better along with be safer...the wastegate will compensate so to not cause problems. running two (2) turbo's from a grand national (one on each bank of cylendars) would allow you to run stock internals on 7psi and not have an abundance of pipes all over the engine bay (well less than what you would have with only 1 turbo). just make sure to get an intercooler since heat=detonation it will greatly reduce the chances of popping the motor
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OK I'll chime in here and throw out my $.02.
Problem with getting a used turbo is just that, it's used. More than likely you are looking at rebuilding it anyway, which depending on the turbo, might cost you a couple hundred dollars just for the rebuild kit. Unless you have rebuilt them before they can be a bit tricky and since they spool at such high rates, tolerances and specs are vital to the life of the unit. Many turbos, especially older KKK, and Garrett's are designed with a 30,000 mile life span. So the odss of getting one of these that does not need to be rebuilt are slim to none. No shaft play, and free spinning wheels do not equal a bolt on and go turbo.
I do not, and I must say this, have any experience what-so-ever turbocharging V8's. Porsches yes, Chevys no. Basics are the same but configuration and desired compressors are vastly different. If you are serious about optimizing the use of a turbo (or 2) you should invest in something like Turbo Calculator, which will give you a very good idea of what would be ideal for your particular engine etc.
There are many ways around just buying a bolt on kit, but in my opinion, unless you are into trial and error engineering, you are better off just going with a proven winner. Ask most ricers and they will eventually agree that blowing motors is common place when trying to work out your own system.
Problem with getting a used turbo is just that, it's used. More than likely you are looking at rebuilding it anyway, which depending on the turbo, might cost you a couple hundred dollars just for the rebuild kit. Unless you have rebuilt them before they can be a bit tricky and since they spool at such high rates, tolerances and specs are vital to the life of the unit. Many turbos, especially older KKK, and Garrett's are designed with a 30,000 mile life span. So the odss of getting one of these that does not need to be rebuilt are slim to none. No shaft play, and free spinning wheels do not equal a bolt on and go turbo.
I do not, and I must say this, have any experience what-so-ever turbocharging V8's. Porsches yes, Chevys no. Basics are the same but configuration and desired compressors are vastly different. If you are serious about optimizing the use of a turbo (or 2) you should invest in something like Turbo Calculator, which will give you a very good idea of what would be ideal for your particular engine etc.
There are many ways around just buying a bolt on kit, but in my opinion, unless you are into trial and error engineering, you are better off just going with a proven winner. Ask most ricers and they will eventually agree that blowing motors is common place when trying to work out your own system.
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alright thanks
i have heard that you only need blowoff valves in standard cars...is this true?? and do i need mandrill bent tubing or can i use 4 inch stainless steel tubing? I've seen both...thanks
i have heard that you only need blowoff valves in standard cars...is this true?? and do i need mandrill bent tubing or can i use 4 inch stainless steel tubing? I've seen both...thanks
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Mandrill bent is going to provide optimum flow and should be used if possible. The ones you have seen that do not have it are loosing velocity as the air passes over the ripples in the bends.
Blow off valve, pop off valve, wastegate all the same function---venting off the charge gases based on a certain amount of pressure in the system. Internally wastegated turbos eliminate the need for any other mechanism to control boost, but they are not adjustable (IIRC) as some wastegates are thus not giving you the option of cranking up the boost.
Blow off valve, pop off valve, wastegate all the same function---venting off the charge gases based on a certain amount of pressure in the system. Internally wastegated turbos eliminate the need for any other mechanism to control boost, but they are not adjustable (IIRC) as some wastegates are thus not giving you the option of cranking up the boost.
933 i think he is talking about blow off valves for releasing pressure between the compressor and the throttle plate(s) between shifts.
now to answer that question: yes it is a good idea to have one. larger turbos dont need them as much as smaller ones do but it helps with response time of respooling after the shift (it may only be a minute amount but its worth it) along with the possibility to have compressor surge if you dont have one. compressor surge is when the air trapped in between the compressor blades and the throttle plate are stuck and the turbo is still spinning fast enough to "charge" the pipes between. the exhaust will still be spinning the turbing and if that happens the compressor side will stop while the turbine side will be spinning which can result in the shaft between the two sides breaking. it is good to have one on any turbo'd vehicle (even tho grand national fellas will tell u differently)
as a note: you need a wastegate (controlls boost) off the manifold or turbo, and a blow off valve (which releases the pressure in the chargepipes fromt the turbo to the throttle plate) to have an efficient system that wont break constantly.
now to answer that question: yes it is a good idea to have one. larger turbos dont need them as much as smaller ones do but it helps with response time of respooling after the shift (it may only be a minute amount but its worth it) along with the possibility to have compressor surge if you dont have one. compressor surge is when the air trapped in between the compressor blades and the throttle plate are stuck and the turbo is still spinning fast enough to "charge" the pipes between. the exhaust will still be spinning the turbing and if that happens the compressor side will stop while the turbine side will be spinning which can result in the shaft between the two sides breaking. it is good to have one on any turbo'd vehicle (even tho grand national fellas will tell u differently)
as a note: you need a wastegate (controlls boost) off the manifold or turbo, and a blow off valve (which releases the pressure in the chargepipes fromt the turbo to the throttle plate) to have an efficient system that wont break constantly.
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My mistake. Not common place on the cars that I work with but good to know anyway. Maybe it should be included in the plan for some upgrades to the P car systems.
Alright, I'm going to throw in my two cents.
Are wastegates mandatory? - No. You can limit boost with either intake or exhaust system restrictions. Control via wastegates is far and away the best way (does putting a restriction in the system sound like a good idea :spank
, but they are not mandatory.
If you want to pick a turbo which is suitable for a particular application, you must first know HOW to pick a turbo. Asking others advice is not always the best method, as the best turbo to use varies with the application: engine size, max RPM, how much power your looking for, are you willing to sacrifice lower RPM power for high RPM power or vice-versa, etc. Another's experiences may not necessarily match up wit hyour objectives. A single turbo can cover a wide range of performance objectives, but it most likely will not cover all of them well. I recommend picking up book such as Hugh MacIness's Turbochargers. This will show you how to calculate airflow rates, read compressor maps, and give you an idea of what you should be looking for in junkyards or in the aftermarket. You should be able to find compressor maps for most of OEM and aftermarket turbos to compare with a few of Google searches.
I almost forgot to comment on blow off valves/recirc valves/bypass valves, whatever you want to call them. My car is an auto with a BOV, and it is going to stay that way. I have forgotten to reconnect the vacuum line to it (rendering it inoperative) a time or two, and the sound of compressor surge if you come out of the throttle quickly is one of the worst sounds I have ever heard, there is no doubt in your mind that damage is being done.
HTH
Are wastegates mandatory? - No. You can limit boost with either intake or exhaust system restrictions. Control via wastegates is far and away the best way (does putting a restriction in the system sound like a good idea :spank
, but they are not mandatory. If you want to pick a turbo which is suitable for a particular application, you must first know HOW to pick a turbo. Asking others advice is not always the best method, as the best turbo to use varies with the application: engine size, max RPM, how much power your looking for, are you willing to sacrifice lower RPM power for high RPM power or vice-versa, etc. Another's experiences may not necessarily match up wit hyour objectives. A single turbo can cover a wide range of performance objectives, but it most likely will not cover all of them well. I recommend picking up book such as Hugh MacIness's Turbochargers. This will show you how to calculate airflow rates, read compressor maps, and give you an idea of what you should be looking for in junkyards or in the aftermarket. You should be able to find compressor maps for most of OEM and aftermarket turbos to compare with a few of Google searches.
I almost forgot to comment on blow off valves/recirc valves/bypass valves, whatever you want to call them. My car is an auto with a BOV, and it is going to stay that way. I have forgotten to reconnect the vacuum line to it (rendering it inoperative) a time or two, and the sound of compressor surge if you come out of the throttle quickly is one of the worst sounds I have ever heard, there is no doubt in your mind that damage is being done.
HTH
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hey slowTurbo, thanks for the tips
so ur saying i dont need a wastegate? but i will need a blowoff valve? i was talking to a guy a he said he used a turbo off of a big diesel truck. a Duramax. He had a small block 350 that had a cam that made power from 25 to 65 rpm. And he said the motor went real fast and had a crazy top end. Any comments?
so ur saying i dont need a wastegate? but i will need a blowoff valve? i was talking to a guy a he said he used a turbo off of a big diesel truck. a Duramax. He had a small block 350 that had a cam that made power from 25 to 65 rpm. And he said the motor went real fast and had a crazy top end. Any comments?
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