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Mountune Fiesta MRX Turbo

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On another note. Does anyone have any driving videos of this unit on and off the throttle. I would be curious to see the transient response of the turbo at various RPM's. Also I have seen no recent response from CPE and their Stainless Cast manifold, but I didnt know if anyone has had any communications as to if that is every going to become a reality or if I should start sourcing a stock manifold so I can port it at home.
 


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Brura22

Brura22

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Thread Starter #682
On another note. Does anyone have any driving videos of this unit on and off the throttle. I would be curious to see the transient response of the turbo at various RPM's. Also I have seen no recent response from CPE and their Stainless Cast manifold, but I didnt know if anyone has had any communications as to if that is every going to become a reality or if I should start sourcing a stock manifold so I can port it at home.
I don't have a video, but when I downshift to pass people the boost is literally instant for me. Off throttle then on throttle has zero lag. Scares me sometimes at highway speeds because of the massive top end


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I don't have a video, but when I downshift to pass people the boost is literally instant for me. Off throttle then on throttle has zero lag. Scares me sometimes at highway speeds because of the massive top end


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I expect videos now after that explanation [deviltail]
 


TyphoonFiST

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Yeah....why has there been no videos for any Turbo setups people have installed....im gonna go wild when I get my stuff a figured and installed to show others what it's like and to get some vendors some business.

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re-rx7

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Yeah....why has there been no videos for any Turbo setups people have installed....im gonna go wild when I get my stuff a figured and installed to show others what it's like and to get some vendors some business.

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I've noticed that as well...
 


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Brura22

Brura22

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I personally am way too busy with the military to even attempt one lol


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As soon as I get my replacement v band (pretty sure I got the notice today for pickup) and when I get the first tunes back from Randy I'll have lots of videos
 


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I'm not looking for excuses son....get it done.

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Sounds like military to me!! Also typhoon your 2554r may be close to that type of no lag with the ported adapter and manifold and turbo blanket and ceramic coated parts


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antarctica24

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That elbow is larger than all hybrids.. then has a coupler that allows the stock size/aftermarket intakes to bolt up. Which is exactly what the hybrids do.
No room for improvement



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It advertises 275/275 on the 2nd pass it's making 300/300. I'd say it did more than they advertised. I'm really starting to understand that it is so much more about moving air than boost. When I was working on my trans am everyone got so worked up about the lbs of boost. Boost is a measurement of restriction. It is possible to make the system flow more efficiently showing less boost and making more power. Were making 300/300 on the wastegate that comes with the turbo. I'm not sure what another wastegate would do considereing this car also has its own boost controller. Randy seems to think theirs more their based on our air flows so I guess we will see.
 


antarctica24

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Did you read the other posts I made?
Mountune has an upgraded WG in testing for this turbo.... sooo clearly they think it'll benefit and they PLAN to offer one.

The Intake and elbow are NO issue. DHM made 400+ with the same elbow and Intake pipe size.

The WG literally explains the "problem" or limit.

It's delivering on its promise, people just want more.

Adam agrees the WG isn't on par with the turbos capabilities.. Does that convince you?
Sure. No need to be rude. I was just looking for a more substantial answer. Like a part number. I'm not sure how it helps but as long as Adam says so it must be true.
 


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It advertises 275/275 on the 2nd pass it's making 300/300. I'd say it did more than they advertised. I'm really starting to understand that it is so much more about moving air than boost. When I was working on my trans am everyone got so worked up about the lbs of boost. Boost is a measurement of restriction. It is possible to make the system flow more efficiently showing less boost and making more power. Were making 300/300 on the wastegate that comes with the turbo. I'm not sure what another wastegate would do considereing this car also has its own boost controller. Randy seems to think theirs more their based on our air flows so I guess we will see.
I believe [MENTION=3707]Turboman17[/MENTION] stated that the boost controller has no meaning if the wastegate is working above its means.


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Messages
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Location
Denver
It advertises 275/275 on the 2nd pass it's making 300/300. I'd say it did more than they advertised. I'm really starting to understand that it is so much more about moving air than boost. When I was working on my trans am everyone got so worked up about the lbs of boost. Boost is a measurement of restriction. It is possible to make the system flow more efficiently showing less boost and making more power. Were making 300/300 on the wastegate that comes with the turbo. I'm not sure what another wastegate would do considereing this car also has its own boost controller. Randy seems to think theirs more their based on our air flows so I guess we will see.
Antartica if what I am about to explain doesn't make sense, please ask more questions and I will do my best to explain it.

The thought process of increasing the wastegate spring is to test whether or not the turbo is going into, what they call the choke zone on the turbine housing, which is where the turbine housing is not large enough to swallow the increased mass of exhaust gasses. And or if the exhaust back pressure created from the boost pressure/exhaust gas pressures are forcing the wastegate open regardless of the boost control soloneids set PSI target.

Exhaust gases inevitably cause back pressure as well as the turbo itself. Often times those exhaust gas pressures inside of the turbos exhaust housing exceed the PSI of what the turbo is producing especially when under load and higher RPMs. It can be more than a 5psi differential between the pressure on the exhaust side and compressor side. So say if the turbo is producing 25psi on the compressor side, the turbine side could be product 30 or more in exhaust pressures depending on the exhaust housings choke point of max exhaust gas flow. Doesn't seem like much but on a small wastegate valve at high speeds, it can be a ton of force.

A stiffer wastegate will show us if infact we are running into a choke flow scenario on the turbine housing, or even the compressor side by elimanting the possibility of the wastegate being forced open by exhaust back pressures.

What it will tell us is this. If we increase boost pressure requirements with a new wastegate, it will do one of two things. Either it will make more boost that shows possitive gains in horsepower which then allows us to keep pushing the turbo to see its limits. Or the wastegate will have no affect at all and or start loosing horsepower.

If the wastegate had no affect at all or lost horsepower, it will then tell us whether or not we are seeing too high of exhaust back pressures (exhaust housing and wheel combo is too small) which will show no increase in boost pressure at all and decrease horsepower because of the backpressure and or Negative change in pressure across the engine. Or that as we increase boost pressure more and more, instead of the turbo creating positive boost, that the engine can use, it instead creates a significant rise in intake air temperatures going into the manifold and sends the comrepssor wheel past efficiency and into again a choke flow state.

Hope I explained it well! I am poor at explaining things at times.
 


antarctica24

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Sure the name of the game is Volumetric Efficiency+Thermal Management = HorsePowwwwaaaaa. The easier the air goes in and out, the better off you are. I would not disagree that on some of these peoples cars there could be some areas where volumetric efficiency could be enhanced. But the general rule of thumb is that you never try to run more than double the boost pressure than what the wastegate spring is rated at. So people have been saying that the MRX is an 11lb spring, then 22psi will be roughly around its limits +/-. Since there is alot of variances of results based on the actuators diaphram size and spring size that can create slight variations in results.

Think of the wastegate as a door. If you put a 100 pound of weight behind the door keeping it closed, but only have 50 pounds of force pushing the door, the door wont open. But if you exceed 100 pounds of force against that door, then the door will open. No matter what electronic nannies you have to control the wastegate, if the exhaust force and or backpressure exceeds the springs strenght, it will open whether it wants to or not. I would assume the 11psi actuator used from Mountune was originally used for the fact that if there is ever an issue and the turbo starts only running wastegate pressure that it will never exceed safe limits that the engine and tuning can handle. If people start running a 22psi actuator, there will be no more safety cushion, so if there is ever a point the turbo runs on only wastegate pressure, the turbo may go into full overspeed chaos mode and hurt the engine, or itself.

Here is something from Gale Banks who is a really knowledgeable guy when it comes to turbochargers.

http://bankspower.com/techarticles/show/15-How-a-Turbo-Wastegate-Works
Thank you this is great information and a great explanation. That helped a lot.
 


antarctica24

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Antartica if what I am about to explain doesn't make sense, please ask more questions and I will do my best to explain it.

The thought process of increasing the wastegate spring is to test whether or not the turbo is going into, what they call the choke zone on the turbine housing, which is where the turbine housing is not large enough to swallow the increased mass of exhaust gasses. And or if the exhaust back pressure created from the boost pressure/exhaust gas pressures are forcing the wastegate open regardless of the boost control soloneids set PSI target.

Exhaust gases inevitably cause back pressure as well as the turbo itself. Often times those exhaust gas pressures inside of the turbos exhaust housing exceed the PSI of what the turbo is producing especially when under load and higher RPMs. It can be more than a 5psi differential between the pressure on the exhaust side and compressor side. So say if the turbo is producing 25psi on the compressor side, the turbine side could be product 30 or more in exhaust pressures depending on the exhaust housings choke point of max exhaust gas flow. Doesn't seem like much but on a small wastegate valve at high speeds, it can be a ton of force.

A stiffer wastegate will show us if infact we are running into a choke flow scenario on the turbine housing, or even the compressor side by elimanting the possibility of the wastegate being forced open by exhaust back pressures.

What it will tell us is this. If we increase boost pressure requirements with a new wastegate, it will do one of two things. Either it will make more boost that shows possitive gains in horsepower which then allows us to keep pushing the turbo to see its limits. Or the wastegate will have no affect at all and or start loosing horsepower.

If the wastegate had no affect at all or lost horsepower, it will then tell us whether or not we are seeing too high of exhaust back pressures (exhaust housing and wheel combo is too small) which will show no increase in boost pressure at all and decrease horsepower because of the backpressure and or Negative change in pressure across the engine. Or that as we increase boost pressure more and more, instead of the turbo creating positive boost, that the engine can use, it instead creates a significant rise in intake air temperatures going into the manifold and sends the comrepssor wheel past efficiency and into again a choke flow state.

Hope I explained it well! I am poor at explaining things at times.
Another great explanation. So let me share this and ask another question. My buddy running this turbo with the map fmic, map hot and cold side pipe, cp-e intake, co-e catless dp and 3" exhaust is making 29psi. What are the limitations on the plastic intake manifold and the crankcase? Certainly that has to be a cocern. What do you think?
 


re-rx7

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Another great explanation. So let me share this and ask another question. My buddy running this turbo with the map fmic, map hot and cold side pipe, cp-e intake, co-e catless dp and 3" exhaust is making 29psi. What are the limitations on the plastic intake manifold and the crankcase? Certainly that has to be a cocern. What do you think?
None with this turbo. Additional CCV will only be need when at 450+ imo.
 


re-rx7

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Antartica if what I am about to explain doesn't make sense, please ask more questions and I will do my best to explain it.

The thought process of increasing the wastegate spring is to test whether or not the turbo is going into, what they call the choke zone on the turbine housing, which is where the turbine housing is not large enough to swallow the increased mass of exhaust gasses. And or if the exhaust back pressure created from the boost pressure/exhaust gas pressures are forcing the wastegate open regardless of the boost control soloneids set PSI target.

Exhaust gases inevitably cause back pressure as well as the turbo itself. Often times those exhaust gas pressures inside of the turbos exhaust housing exceed the PSI of what the turbo is producing especially when under load and higher RPMs. It can be more than a 5psi differential between the pressure on the exhaust side and compressor side. So say if the turbo is producing 25psi on the compressor side, the turbine side could be product 30 or more in exhaust pressures depending on the exhaust housings choke point of max exhaust gas flow. Doesn't seem like much but on a small wastegate valve at high speeds, it can be a ton of force.

A stiffer wastegate will show us if infact we are running into a choke flow scenario on the turbine housing, or even the compressor side by elimanting the possibility of the wastegate being forced open by exhaust back pressures.

What it will tell us is this. If we increase boost pressure requirements with a new wastegate, it will do one of two things. Either it will make more boost that shows possitive gains in horsepower which then allows us to keep pushing the turbo to see its limits. Or the wastegate will have no affect at all and or start loosing horsepower.

If the wastegate had no affect at all or lost horsepower, it will then tell us whether or not we are seeing too high of exhaust back pressures (exhaust housing and wheel combo is too small) which will show no increase in boost pressure at all and decrease horsepower because of the backpressure and or Negative change in pressure across the engine. Or that as we increase boost pressure more and more, instead of the turbo creating positive boost, that the engine can use, it instead creates a significant rise in intake air temperatures going into the manifold and sends the comrepssor wheel past efficiency and into again a choke flow state.

Hope I explained it well! I am poor at explaining things at times.
It's technical and by the book for sure. I think alot of people on here would benefit from examples. Choking the turbo is essentially whre you are chopping air instead of compressing it. It gets super hot. Just an example. As always, great post.
 


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It's technical and by the book for sure. I think alot of people on here would benefit from examples. Choking the turbo is essentially whre you are chopping air instead of compressing it. It gets super hot. Just an example. As always, great post.
Very good point RE-rx7. And I agree that both the intake manifold and crankcase ventilation system both will be saitssctory for anything under 450. That is unless for some reason that there is already excessive blow by on someone's specific engine, in which the boost will amplify it. But at that point the person will be worrying about a rebuild and not the turbo.

Engines are simple, yet complex beasts. Based on your screen name RE-rx7, I would assume you have dove into the rotary world at some point?
 


antarctica24

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None with this turbo. Additional CCV will only be need when at 450+ imo.
Ok I'm asking so be cool, so if we're talking about 450hp then if 29psi is making 300hp then to make 450hp on this turbo if it could make that power we're talking about something like 45psi would be the upper limit of the plastic intake manifold and crankcase? I think the bottom end is only good to what 350? 400? Someone blew one up but I don't remember what the power was. I'm still having an issue here on what the limitation of boost would be. You could have 20psi and make 450hp right, I think the internals have a limit but the cylinder head bolts, plastic intake manifold, and crank case, the piston rings certainly in stock configuration could not deal with 45psi, is that what your saying? If that is really the case then does that mean the wastegate was chosen by Mountune due to safety was over zealous?
 




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