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Divided housing turbo / manifold questions


jevansio
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My current manifold has become damaged on the flange (the divided bit). Got a couple of questions.

 

Is it OK to run a divided manifold with a none divided housing?

 

Are you better off running a divided turbo if running a divided manifold?

 

Exactly what are the benefits of running a divided setup?

 

If I run a non-diveded hosuing currently (say 0.81 A/R) and the next turbo I get I want the same characteristics but with a divided housing, do I just get the next size up (i.e a 0.96 divided housing)?

 

ta

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In answer to your first question, no as it creates a hot spot due to the shape and proximity to the housing, which can start to melt and by by turbo.

 

Second question yes!

 

Third, not to sure but have heard it improves spool up.

 

Fourth, i was always under the impression that the larger the housing the slower the response, all things being equal, but it also depends on the compressor side.

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In answer to your first question, no as it creates a hot spot due to the shape and proximity to the housing, which can start to melt and by by turbo.

 

Second question yes!

 

Third, not to sure but have heard it improves spool up.

 

Fourth, i was always under the impression that the larger the housing the slower the response, all things being equal, but it also depends on the compressor side.

 

Sorry but this is simply not true.. You can very well run a divided manifold with a non divided housing. many people do that.

Take for example the big boys running T6 platforms, Garrett doesn't make a 4788 divided and people run VWR and FR manifolds with non divided 4788's all the time.

 

 

But yes, spool is greatly enhanced on a fully divided setup.

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You can run undivided turbo housings on divided manifolds, there is nothing to stop you doing the same the other way either but it will create a hot spot where the exhaust flow is met with a restriction.

 

My current setup is an undivided cast manifold and a divided .70 a/r exhaust housing, on last inspection many moons ago the exhaust housing had cracked around the divider ;)

 

If you have a proper divided manifold, ie the exhaust pulses are configured for the correct half of the divide, not front 3 and back 3 it does help spool when matched with a divided turbo exhaust housing.

 

As for sizings you should go smaller with undivided as the divided A/Rs are larger to cater for the extra chunk of material in the middle, thats how it was explained to me anyway :D

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Sorry but this is simply not true.. You can very well run a divided manifold with a non divided housing. many people do that.

Take for example the big boys running T6 platforms, Garrett doesn't make a 4788 divided and people run VWR and FR manifolds with non divided 4788's all the time.

 

 

But yes, spool is greatly enhanced on a fully divided setup.

 

I was actually referring to jevansio's manifold in particular, as he has had problems, and if you take a look at his divided manifold you can clearly see where it has become too hot and started to melt, I'm sure if a manifold is very well made and the turbo is not subjected to high EGTs it will be fine, personally i wouldn't take the risk.

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