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Discussion Starter · #1 ·

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The turbos on the later Evos are twin scroll, so even if these work in theory on single scroll turbos, it wouldn't work on the Evo as you'd effectively be blocking two of the exhaust ports from the head. :blah:
 

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Discussion Starter · #3 ·
The turbos on the later Evos are twin scroll, so even if these work in theory on single scroll turbos, it wouldn't work on the Evo as you'd effectively be blocking two of the exhaust ports from the head. :blah:
what you do is use a single scroll manifold with a Twin scroll turbo and one of these valves. the valve then forces all the ehaust gas through one side of the turbo thus halfing the AR. this results in faster spool up. then once you reach a decent presure the valve starts to open and allows the ehust gasses to pass through both side of the turbo. this means back preusre is not effected.

so basically you are halving the AR of the turbo until a fixed boost presure is reached. then you open up the turbo and allow it to really breath!

this, as shown in the above link, allows you to run a larger turbo with a larger AR. this helps reduce backpresure at higher RPM making more power as well as running a larger turbo with similar spool to a smaller unit.

Cheers

Chris.
 

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If you double the pressure of the gas flow by halving the area it has to flow through, thereby halving the area the gas can "push against", don't you just arrive at the same force as if you left it standard?

Sounds suspiciously like snake oil to my uneducated brain, but I'm sure some of the more learned members can comment.
 

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*looks like snake oil but let's see...*
*clicks url*
*reads "It's like nitrous but you'll never have to fill a bottle again"*
*presses Alt-F4*
 

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Seems sensible to me and makes sense. You effectively divert the flow from all 4 exhaust ports to a single scroll of the turbo thereby increasing the velocity that impinges on the blades and allowing a faster spool.

The only problem I can see is that obviously installing this will create a pressure drop across the valve and so it's whether or not the increase in kinetic energy is enought to outweigh the loss caused by the pressure drop.

I disagree that it will make more top end power because even when it's fully open, you will be losing pressure across the valve and so the amount of energy in the exhaust gas hitting the turbo will be reduced.

Finally, the only problem with fitting it to a std Evo is that it has a split manifold design already so it would only really work if you changed the manifold as well.

Andy
 

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what you do is use a single scroll manifold with a Twin scroll turbo and one of these valves. the valve then forces all the ehaust gas through one side of the turbo thus halfing the AR. this results in faster spool up. then once you reach a decent presure the valve starts to open and allows the ehust gasses to pass through both side of the turbo. this means back preusre is not effected.

so basically you are halving the AR of the turbo until a fixed boost presure is reached. then you open up the turbo and allow it to really breath!

this, as shown in the above link, allows you to run a larger turbo with a larger AR. this helps reduce backpresure at higher RPM making more power as well as running a larger turbo with similar spool to a smaller unit.

Cheers

Chris.
Umm.....am i missing something or does a wastegate not do this job allready. Cant see it working myself.
 

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Discussion Starter · #9 ·
come on guys! read this guys results!

http://www.ls1tech.com/forums/forced...ke-graphs.html

he has data logged 7pulls (deleted the fastest and slowest spooling) both with and without the valve fitted. Results are clear.

results showed a 33% reduction in spool time.

ok let me take it back a bit as i dont think you guys have heard of people doing this. we all understand that if you block off half a twin scroll turbo you are basically halving the AR of the turbo. and we all understand that a smaller AR will result in a faster spooling turbo. well some guys tried this on by simply blocking half the housing up and got there turbos to spool super fast! the problem was higher up the RPM range you get MASSIVE backpresure.

soooo guys started using a (second) weastgate to allow the exhaust to now pass through to the blocked housing once 'full presre' is reached.

this then gave you a turbo that would spool fast and not have the packpresure issues of simply blocking off half the trubo (we are tlaking about divided housing turbos here!!!).

now trying to shoehord a second weastgate into a already crampt engine bay is hard, esp when you have to mount it in the exhaust track to the turbo AND have it vent back into the turbo. This waswhen this vavle was created.

Just imagine 33% reducetion in spool time in an EVO! engine being able to run a GT40 and getting the same spool times as a GT35 engined car!

Im not trying to sell these just trying to show people new and hopefully intresting stuff.

Cheers

Chris.
 

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come on guys! read this guys results!

http://www.ls1tech.com/forums/forced...ke-graphs.html

he has data logged 7pulls (deleted the fastest and slowest spooling) both with and without the valve fitted. Results are clear.

results showed a 33% reduction in spool time.

ok let me take it back a bit as i dont think you guys have heard of people doing this. we all understand that if you block off half a twin scroll turbo you are basically halving the AR of the turbo. and we all understand that a smaller AR will result in a faster spooling turbo. well some guys tried this on by simply blocking half the housing up and got there turbos to spool super fast! the problem was higher up the RPM range you get MASSIVE backpresure.

soooo guys started using a (second) weastgate to allow the exhaust to now pass through to the blocked housing once 'full presre' is reached.

this then gave you a turbo that would spool fast and not have the packpresure issues of simply blocking off half the trubo (we are tlaking about divided housing turbos here!!!).

now trying to shoehord a second weastgate into a already crampt engine bay is hard, esp when you have to mount it in the exhaust track to the turbo AND have it vent back into the turbo. This waswhen this vavle was created.

Just imagine 33% reducetion in spool time in an EVO! engine being able to run a GT40 and getting the same spool times as a GT35 engined car!

Im not trying to sell these just trying to show people new and hopefully intresting stuff.

Cheers

Chris.
Do you sell these or something? If you're so convinced, buy one, put it on your car, and send us the results :smthumbup
 

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Test data aside i would be worried about a single throttle blade sat in 1000 degrees of hot gas. How thick is this plate i wonder? Is it made of inconel or just steel?
Another thing is twin scroll turbos are designed to split the pulses so the gas is diverted across the turbine in a controlled manner and sending it to one side of the turbine (when this valve is working) MAY cause stress on the one end of the turbine wheel. Im no expert but they are my concerns. I certainly wouldnt want my engine eating part of a turbine blade if it breaks .

Tony
 

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Discussion Starter · #14 ·
Tony i guess its the same material as what is used on sequential turbo setups. it would be intresting to see how long term these hold up. i cant really see much deiff between this and say a sequential turbo but i dont know material the manufactures use.

what about the ability to run larger turbos with the same spool up? surge could be a problem with smaller turbos. Larger AR turbine hoyusings could be used to help reduce surge.

are there any other downsides? if you are running a larger turbine housing/blade wouldn't this result in lower backpresures and thus reduced temps?

Cheers

Chris.
 

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It won't reduce backpressure at all, it will increase it as it is another restriction in the exhaust.

As for running large turbos with the same spool up as small ones then I'm afraid you are going to be massively disappointed IMO if you think this will achieve that. Yes, there may be some gain from the increased exhaust velocity but it isn't going to make a massive difference due to the fact that because of the extra pressure drop across the throttle plate, the pressure of the gas hitting the turbo will be less.

Andy
 
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