New 38mm MVS O2 Eliminator Downpipe from MAPerformance!
I am curious to see how this effects the benifits of a twin scroll housing when you allow the divided sides to bleed into each other. Im sure it will delay spoolup to some extent. As far as regulating boost an external wastegate will be superior to a flaper style internal gate, so expect to hold more boost to redline for sure. I am very excited to see the results of this idea.
Bryan
Bryan
If I hadn't have had so many problems with their integrated o2/dp I might consider this but the performance of the other piece (Horrible creep issues) will keep me from buying it for my Red.
Also, if you are flowing enough air through your bypass holes in the hotside, this will still creep. The construction of the mount is such that it does not promote good air circulation. The hole for the wastegate side is smaller than the hole in the housing and larger than the stock flapper so the air is coming out of the bypass holes, into the hotside, then has to swirl around trying to escape into the wastegate dump tube area.
Believe me, I have struggled to make the o2/dp integrated piece flow properly and when you are flowing as much air as I am, it just won't work with this type of construction. They need to have an extension piece that goes up out of the mount area and into the bypass/flapper area to create a direct flow from the bypass holes and into the wastegate tube
It looks pretty, but it won't work under all conditions. If you have a stock turbo, perhaps, but with a red and a lot of porting, no sir.
Also, if you are flowing enough air through your bypass holes in the hotside, this will still creep. The construction of the mount is such that it does not promote good air circulation. The hole for the wastegate side is smaller than the hole in the housing and larger than the stock flapper so the air is coming out of the bypass holes, into the hotside, then has to swirl around trying to escape into the wastegate dump tube area.
Believe me, I have struggled to make the o2/dp integrated piece flow properly and when you are flowing as much air as I am, it just won't work with this type of construction. They need to have an extension piece that goes up out of the mount area and into the bypass/flapper area to create a direct flow from the bypass holes and into the wastegate tube
It looks pretty, but it won't work under all conditions. If you have a stock turbo, perhaps, but with a red and a lot of porting, no sir.
The biggest issue I can see is our stock turbo turbine housing is divided, essintially two seperated housings even as they reach the turbine wheel. They are kept divided by the factory flapper(or flappers) until enough boost is made to over power the spring in the wastegate actuator. One you have reached x ammount of boost the flapper opens and starts to bleed off pressure in the turbine housing, however by this point the turbo is already spooled and is now concerned with equalizing pressure in the housings and regulating boost levels. Until that point it keeps both sides of the turbine housing segregated. When you remove the flapper you have now removed the only part in the housing keeping it divided or twin scroll. Now the exh energy can bleed between the two divided housings instead of powering the turbine wheel. Unfortunatly with our stock turbine housing, or most of the twin scroll housings I have seen, there is no way to effectivly externally gate them with one wastegate or off the turbine housing. Again I am very curious to see how this works out and I am by no means trying to be a party pooper.
Bryan
Bryan
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From: Minnesota
If I hadn't have had so many problems with their integrated o2/dp I might consider this but the performance of the other piece (Horrible creep issues) will keep me from buying it for my Red.
Also, if you are flowing enough air through your bypass holes in the hotside, this will still creep. The construction of the mount is such that it does not promote good air circulation. The hole for the wastegate side is smaller than the hole in the housing and larger than the stock flapper so the air is coming out of the bypass holes, into the hotside, then has to swirl around trying to escape into the wastegate dump tube area.
Believe me, I have struggled to make the o2/dp integrated piece flow properly and when you are flowing as much air as I am, it just won't work with this type of construction. They need to have an extension piece that goes up out of the mount area and into the bypass/flapper area to create a direct flow from the bypass holes and into the wastegate tube
It looks pretty, but it won't work under all conditions. If you have a stock turbo, perhaps, but with a red and a lot of porting, no sir.
Also, if you are flowing enough air through your bypass holes in the hotside, this will still creep. The construction of the mount is such that it does not promote good air circulation. The hole for the wastegate side is smaller than the hole in the housing and larger than the stock flapper so the air is coming out of the bypass holes, into the hotside, then has to swirl around trying to escape into the wastegate dump tube area.
Believe me, I have struggled to make the o2/dp integrated piece flow properly and when you are flowing as much air as I am, it just won't work with this type of construction. They need to have an extension piece that goes up out of the mount area and into the bypass/flapper area to create a direct flow from the bypass holes and into the wastegate tube
It looks pretty, but it won't work under all conditions. If you have a stock turbo, perhaps, but with a red and a lot of porting, no sir.
Having more restrictions in your exhaust system, (cats, non-mandrel bent plumbing, restrictive housings, ext) will limit the amount of exhaust gasses that can be passed through, and therefore not allow a turbo setup to even be able to boost creep. If you are seeing boost creep after the addition of some exhaust component to your setup, that means you have increase the efficiency of the exhaust setup as a whole.... making the change a good thing, although you may need to upgrade other components as well (like the necessity of having larger injectors for a larger turbo).
If you have a wastegate setup appropriately for your turbo/flow requirements, you will NOT have creep. You said it yourself, you have a red that is ported, but still are utilizing a WG setup designed for a stock sized turbo? There's your issue, fix that and I'm sure you will not have any more creep.
Hope that helps explain things!
-Bob
Last edited by Bob@MAPerf; May 5, 2009 at 05:02 PM.
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From: Minnesota
The biggest issue I can see is our stock turbo turbine housing is divided, essentially two separated housings even as they reach the turbine wheel. They are kept divided by the factory flapper(or flappers) until enough boost is made to over power the spring in the wastegate actuator. One you have reached x amount of boost the flapper opens and starts to bleed off pressure in the turbine housing, however by this point the turbo is already spooled and is now concerned with equalizing pressure in the housings and regulating boost levels. Until that point it keeps both sides of the turbine housing segregated. When you remove the flapper you have now removed the only part in the housing keeping it divided or twin scroll. Now the exh energy can bleed between the two divided housings instead of powering the turbine wheel. Unfortunately with our stock turbine housing, or most of the twin scroll housings I have seen, there is no way to effectively externally gate them with one wastegate or off the turbine housing. Again I am very curious to see how this works out and I am by no means trying to be a party pooper.
Bryan
Bryan
Make sense?
-Bob
Last edited by Bob@MAPerf; May 5, 2009 at 05:03 PM.
Take a look at what I bolded above and please explain how you can see any boost creep if you have an adequate wastegate setup.....
Having more restrictions in your exhaust system, (cats, non-mandral bent plumbing, restrictive housings, ext) will limit the amount of exhaust gasses that can be passed through, and therefore not allow a turbo setup to even be able to boost creep. If you are seeing boost creep after the addition of some exhaust component to your setup, that means you have increase the efficiency of the exhaust setup as a whole.... making the change a good thing, although you may need to upgrade other components as well (like the necessity of having larger injectors for a larger turbo).
If you have a wastegate setup appropriately for your turbo/flow requirements, you will NOT have creep. You said it yourself, you have a red that is ported, but still are utilizing a WG setup designed for a stock sized turbo? There's your issue, fix that and I'm sure you will not have any more creep.
Hope that helps explain things!
-Bob
Having more restrictions in your exhaust system, (cats, non-mandral bent plumbing, restrictive housings, ext) will limit the amount of exhaust gasses that can be passed through, and therefore not allow a turbo setup to even be able to boost creep. If you are seeing boost creep after the addition of some exhaust component to your setup, that means you have increase the efficiency of the exhaust setup as a whole.... making the change a good thing, although you may need to upgrade other components as well (like the necessity of having larger injectors for a larger turbo).
If you have a wastegate setup appropriately for your turbo/flow requirements, you will NOT have creep. You said it yourself, you have a red that is ported, but still are utilizing a WG setup designed for a stock sized turbo? There's your issue, fix that and I'm sure you will not have any more creep.
Hope that helps explain things!
-Bob
I am surte it works for some, but I am nto the only person who has had creep issues with the integrated piece. Now, this piece is different, but still retains the same issue at the hotside based on the build.
I wish you all the best of luck and hope I am totally wrong.
Trying to use the integrated o2/dp has cost me over $1000 so far though, so I won't be trying or supporting any further "test" pieces like this in the future
Good luck again
Bryan, I don't disagree with anything you stated, but I think you are missing the quantity of exhaust flow that would 'jump' from one scroll to the other through the WG holes. It's a little tough to have a significant amount of exhaust flow take a 90 degree turn into the WG hole, then take a 180 into the other scroll, then another 90 into it's exhaust flow. Can it happen? Yes. Does it on externally gated setups? I;'m sure it does but again, not in a significant amount.
Make sense?
-Bob
Make sense?
-Bob
Bryan
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I think what Bob is trying to say is that the full 3" design of the downpipe may have improved your exhaust system as a whole (therefore improving spool characteristics as well as top end horsepower) to an extent in which there was such a reduction in back pressure that boost creep cannot be eliminated with the factory wastegate configuration.
I will let Bob comment on the airflow aspects of your response, after all that's what he does for a living 
There seems to be too much surface area where the piece meets the hotside. Two small holes, but with air flowing through a much larger hole with no means to flow directly into the pipe. It justs swirls against a wall (The pipe) and hopes to flow down through the hole at some point.
Last edited by maperformance; May 6, 2009 at 09:16 AM.
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From: Minnesota
I think what Bob is trying to say is that the full 3" design of the downpipe may have improved your exhaust system as a whole (therefore improving spool characteristics as well as top end horsepower) to an extent in which there was such a reduction in back pressure that boost creep cannot be eliminated with the factory wastegate configuration.
I will let Bob comment on the airflow aspects of your response, after all that's what he does for a living
I will let Bob comment on the airflow aspects of your response, after all that's what he does for a living
Sometimes I get too technical and the actual answer gets masked, but Chris recapped it a bit more consice than I had.
