stock exhaust manifold for turbo?
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A few points to bring up:
Messing with emmissions equipment is illegal anywhere that has emissions laws. That includes removing, moving and replacing with a non-approved substitute. So moving the catalytic converter is definitely an "Off-road use only" measure.
Putting a turbo flange onto a cast iron manifold is a bad idea. Maybe if you can have a flange that bolts onto the manifold fabricated, but if you are going to go that far, you might as well just buy a manifold. You'll be much better off in the long run.
Boost creep is bad. The most common root of the problem for boost creep is a restriction in the wastegate chamber. The wastegate itself should be able to handle the exhaust gasses if the turbo is well matched to the engine. Many Supra owners have stopped boost creep problems by upgrading the exhaust as well.
Messing with emmissions equipment is illegal anywhere that has emissions laws. That includes removing, moving and replacing with a non-approved substitute. So moving the catalytic converter is definitely an "Off-road use only" measure.
Putting a turbo flange onto a cast iron manifold is a bad idea. Maybe if you can have a flange that bolts onto the manifold fabricated, but if you are going to go that far, you might as well just buy a manifold. You'll be much better off in the long run.
Boost creep is bad. The most common root of the problem for boost creep is a restriction in the wastegate chamber. The wastegate itself should be able to handle the exhaust gasses if the turbo is well matched to the engine. Many Supra owners have stopped boost creep problems by upgrading the exhaust as well.
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QUOTE
SupraGuy:
A few points to bring up:
Many Supra owners have stopped boost creep problems by upgrading the exhaust as well.
The Turbo kit i have is teh Alpine Turbo kit and ITS made for the Tiburon.I also have a 3inch downpipe and exhaust and this actually made the Creep to go higher?
A few points to bring up:
Many Supra owners have stopped boost creep problems by upgrading the exhaust as well.
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I can't speak to the Alpine kit, having never seen it, but I would hypothesize that the wastegate design isn't adequate to the amount of boost that you're running, or is poorly located.
The wastegate has to be able to allow enough exhaust gasses to bypass the compressor turbine so that the turbine cannot create enough power to force further compression of the intake charge. If the wastegate cannot allow enough bypass then you get boost creep.
Upgrading the exhaust should only HELP boost creep because there will be less backpressure at the wastegate dump site, allowing the wastegate opening to expell more exhaust gasses, leaving less to go through the turbine -- in a well-designed system.
The other side of an upgraded exhaust is that there is less pressure at the turbine outlet as well, and if the exhaust gasses are padding through the turbine, it makes more power available to compress the intake charge. Normally this is a good thing, but if the wastegate is not allowing enough exhaust to bypass the compressor, that would be the only way that I could see boost creep problems getting worse.
The wastegate does not act alone, however. Once the wastegate opens, there has to be a low restriction path into the exhaust stream. A poorly designed downpipe can cause backpressure in the wastegate system to increase, making it less effective.
To troubleshoot, first make sure that your wastegate is opening completely under the requisite pressure at the actuator. Then make sure that you are getting proper pressure at the actuator, and lastly, ensure that you have a good path to exhaust from the wastegate. If all these requirements are met, and you still have trouble with boost creep, then you will need to supplement the wastegate in order to control boost at the desired pressure. If you can't do that, then you'll have to turn the boost down. tongue.gif (Yeah, I'd fix it, too. smile.gif )
The wastegate has to be able to allow enough exhaust gasses to bypass the compressor turbine so that the turbine cannot create enough power to force further compression of the intake charge. If the wastegate cannot allow enough bypass then you get boost creep.
Upgrading the exhaust should only HELP boost creep because there will be less backpressure at the wastegate dump site, allowing the wastegate opening to expell more exhaust gasses, leaving less to go through the turbine -- in a well-designed system.
The other side of an upgraded exhaust is that there is less pressure at the turbine outlet as well, and if the exhaust gasses are padding through the turbine, it makes more power available to compress the intake charge. Normally this is a good thing, but if the wastegate is not allowing enough exhaust to bypass the compressor, that would be the only way that I could see boost creep problems getting worse.
The wastegate does not act alone, however. Once the wastegate opens, there has to be a low restriction path into the exhaust stream. A poorly designed downpipe can cause backpressure in the wastegate system to increase, making it less effective.
To troubleshoot, first make sure that your wastegate is opening completely under the requisite pressure at the actuator. Then make sure that you are getting proper pressure at the actuator, and lastly, ensure that you have a good path to exhaust from the wastegate. If all these requirements are met, and you still have trouble with boost creep, then you will need to supplement the wastegate in order to control boost at the desired pressure. If you can't do that, then you'll have to turn the boost down. tongue.gif (Yeah, I'd fix it, too. smile.gif )
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QUOTE
SupraGuy:
To troubleshoot, first make sure that your wastegate is opening completely under the requisite pressure at the actuator. Then make sure that you are getting proper pressure at the actuator, and lastly, ensure that you have a good path to exhaust from the wastegate. If all these requirements are met, and you still have trouble with boost creep, then you will need to supplement the wastegate in order to control boost at the desired pressure. If you can't do that, then you'll have to turn the boost down. :p (Yeah, I'd fix it, too.
)
I have wired my wastegate FULLY opened and i still got 10PSI of boost.I am running stock compression at 10:1 and have my internal wastegate is set to 5psi and creeps up to 13psi in the Higher RPM range!!To troubleshoot, first make sure that your wastegate is opening completely under the requisite pressure at the actuator. Then make sure that you are getting proper pressure at the actuator, and lastly, ensure that you have a good path to exhaust from the wastegate. If all these requirements are met, and you still have trouble with boost creep, then you will need to supplement the wastegate in order to control boost at the desired pressure. If you can't do that, then you'll have to turn the boost down. :p (Yeah, I'd fix it, too.
)Once i hit over 4500rpms and as i get higher in the gears it just Creeps up!
The Alpine kit is designed with the HeadSpacer which drops your compression down to 8.2:1 BUT in my case it will drop it down to 7.9:1 Being that i have a 1.8L Tiburon.
The ONLY Other Alternative is no install an External wastegate(35mmTial) and mount it where all 4 collecters meet at the Flange for the best possible location and accuracy for the Boost to stay consistant at!!!!
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2 UNIQ Just a question do you have a 100% full custom exhaust system. Or have they left any part of the old system in there. The reason i ask is when i first had my turbo fitted i couldnt afford the full system straight away. so the adapted my old one. But what they found is just after where the old cat is fitted and the pipe goes under the car there is that mesh part(its a flexi part of the pipe which a lot of custom workers utilise and leave in the system) well right next to this is a restrictor inside which the guys who did mine descovered by chance. They said if we hadnt of spotted that i could of ended up with the same probs you are having due to the gasses not getting out fast enough. Just a thought.
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QUOTE
2 UNIQ:
I have wired my wastegate FULLY opened and i still got 10PSI of boost.I am running stock compression at 10:1 and have my internal wastegate is set to 5psi and creeps up to 13psi in the Higher RPM range!!
Once i hit over 4500rpms and as i get higher in the gears it just Creeps up!
The Alpine kit is designed with the HeadSpacer which drops your compression down to 8.2:1 BUT in my case it will drop it down to 7.9:1 Being that i have a 1.8L Tiburon.
The ONLY Other Alternative is no install an External wastegate(35mmTial) and mount it where all 4 collecters meet at the Flange for the best possible location and accuracy for the Boost to stay consistant at!!!!
This is not good...I have wired my wastegate FULLY opened and i still got 10PSI of boost.I am running stock compression at 10:1 and have my internal wastegate is set to 5psi and creeps up to 13psi in the Higher RPM range!!
Once i hit over 4500rpms and as i get higher in the gears it just Creeps up!
The Alpine kit is designed with the HeadSpacer which drops your compression down to 8.2:1 BUT in my case it will drop it down to 7.9:1 Being that i have a 1.8L Tiburon.
The ONLY Other Alternative is no install an External wastegate(35mmTial) and mount it where all 4 collecters meet at the Flange for the best possible location and accuracy for the Boost to stay consistant at!!!!
10:1 compression should be okay, depending on how much boost you want to run. 5-6 psi should still be okay on pump gas with that. 8.5:1 should be manageable up to 16-18 psi.
You've definitely got some problems with the hot side of your turbo. The wastegate just isn't clearing pressure fast enough. This is hard on your valve train, as well as giving you way too much boost pressure.
If you're getting boost AT ALL with your wastegate wired full open, then you've got exhaust system issues to deal with. An external wastegate mioght help, but I'd take a good look at what's in the exhaust system first.
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Jon!
Since my Tibby is the 1.8L it only came with ONE CAT from the factory which is installed underneath the car as opposed to the 2.0L Tiburons that come with TWO Cats which are located in the Engine Bay underneath the stock exhaust manifold and one underneath the car!!
That being said i have a FULL Custom exhaust system made with a 3INCH Downpipe as well and im not using the Downpipe that came with the Alpine kit which is 2.25inch in size!!
I enlarged the downpipe to a custom mandrel bend 3 inch exhaust which i thought would of eliminate the creeping but it actually made it worse by 1-2 PSI HIGHER
Supraguy!
As i mentioned above i have a COMPLETE exhaust system on my Tiburon and the ONLY ALTERNATIVE is to install the External wastegate to eliminate the creeping.My problem doesnt lie on the exhaust side as its MORE THAN ENOUGH
Since my Tibby is the 1.8L it only came with ONE CAT from the factory which is installed underneath the car as opposed to the 2.0L Tiburons that come with TWO Cats which are located in the Engine Bay underneath the stock exhaust manifold and one underneath the car!!
That being said i have a FULL Custom exhaust system made with a 3INCH Downpipe as well and im not using the Downpipe that came with the Alpine kit which is 2.25inch in size!!
I enlarged the downpipe to a custom mandrel bend 3 inch exhaust which i thought would of eliminate the creeping but it actually made it worse by 1-2 PSI HIGHER
Supraguy!
As i mentioned above i have a COMPLETE exhaust system on my Tiburon and the ONLY ALTERNATIVE is to install the External wastegate to eliminate the creeping.My problem doesnt lie on the exhaust side as its MORE THAN ENOUGH
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Why would it be harder on valve train?
right, he might burn an exaust valve but before that i'm sure he'll melt or break a piston....
Larger exaust will create more boost because you have less backpressure...
less back pressure mean more "air" will pass trough the turnine wheel and less will pass trough the waste gate when it's opened
i did see that happen often on car with small turbochargers... install a large exaust and sudently the boost is out of control...
what he need to do is to enlarged the wastegate hole and puck it' simple.. (some porting of the wastegate area might be a good idea too)i can't figure why you would want ot mess up with the entire exaust system to cure a simle thing like that
Denis
right, he might burn an exaust valve but before that i'm sure he'll melt or break a piston....
Larger exaust will create more boost because you have less backpressure...
less back pressure mean more "air" will pass trough the turnine wheel and less will pass trough the waste gate when it's opened
i did see that happen often on car with small turbochargers... install a large exaust and sudently the boost is out of control...
what he need to do is to enlarged the wastegate hole and puck it' simple.. (some porting of the wastegate area might be a good idea too)i can't figure why you would want ot mess up with the entire exaust system to cure a simle thing like that
Denis
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Denisst99!!
This is excatly what im trying to say that when you enlarge the DOWNPIPE/Exhaust system the Boost becomes EVEN more UN-controlable.
The only ALTERNATIVE as i mentioned is to install an EXTERNAL wastegte PERIOD.......
This is my ONLY solution.......
I aslso enlarged my Internal wastegate by 5mm and still NOTHING.Alpine sent me a NEW Turbo Housing which he bored out and the creeping was still noticeable.
Now im going to built a NEW manifold which is a BETTER design and flows better which will help ALOT when i install the External wastegate smile.gif smile.gif smile.gif
This is excatly what im trying to say that when you enlarge the DOWNPIPE/Exhaust system the Boost becomes EVEN more UN-controlable.
The only ALTERNATIVE as i mentioned is to install an EXTERNAL wastegte PERIOD.......
This is my ONLY solution.......
I aslso enlarged my Internal wastegate by 5mm and still NOTHING.Alpine sent me a NEW Turbo Housing which he bored out and the creeping was still noticeable.
Now im going to built a NEW manifold which is a BETTER design and flows better which will help ALOT when i install the External wastegate smile.gif smile.gif smile.gif
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Okay...
All that I was trying to say is that if your wastegate is adequate then the only reason that you should be experiencing boost creep is if your exhaust is not.
As for lower restriction exhasut, yes. It does help you boost faster by increasing the pressure differential across the turbine. However, it ALSO increases the pressure differential across the wastegate, making the wastegate more efective. And, as I've said, many Supra owners have solved boost creep problems by upgrading their exhaust systems.
Given the information that you've stated, then I'd have to agree that your current wastegate is not adequate to the amount of flow required of it, and you will have to supplement it with an external wastegate.
All that I was trying to say is that if your wastegate is adequate then the only reason that you should be experiencing boost creep is if your exhaust is not.
As for lower restriction exhasut, yes. It does help you boost faster by increasing the pressure differential across the turbine. However, it ALSO increases the pressure differential across the wastegate, making the wastegate more efective. And, as I've said, many Supra owners have solved boost creep problems by upgrading their exhaust systems.
Given the information that you've stated, then I'd have to agree that your current wastegate is not adequate to the amount of flow required of it, and you will have to supplement it with an external wastegate.