Turboing a 1uz using crown log manifolds ..

[lexsmaz]

Hi,
I have fitted a 1uz to my 929 Mazda a while ago, good little motor but i am contemplating putting a single turbo on it, ( personally you can't beat that turbo rush ) ..

I was thinking of using the turbo off a XR6 Falcon, but due to space restrictions will probably need to leave the Crown log manifolds on it, or at least on the drivers side to clear the rack, i realise these are very poor flowing manifolds, but in a turbo setup how poor ? so i am curious if any one has used these manifolds initially on a turbo setup & then changed manifolds to something better & what gains were made ?? ..

Thanks in advance ..

Rob ..

 

[XR8tt]

The manifold is not as important as its under pressure in turbo application and the power levels you are after the std manifolds will do fine..
However if you want to modify them?
I would change the 90* onto log to closer 45* angle for better flow..
The GT35/40 is a good choice, internal gated less complex. But check or improve wastegate flow...

 

[JustenGT8]

I've seen the log manifold deliver 250rwkw easy enough

 

[lexsmaz]

Thanks guy's for the feedback,

Justen how much boost pressure did the engine you saw with 250 rwkw have ?
i would be more than happy with that sort of a figure for my application .. Do you know what other things were done to the engine as in comp ratio, injectors, computers etc for him to achieve that 250 rwkw ...

XR8tt, i agree with you & realise that under boost situation the manifolds aren't quite as critical, but what i was curious about was as to how much they are holding it back by, hence the question if someone had done the standard log manifold option initially, then changed to some better flowing ones, but i am also aware not many would have gone down that route ....

Thanks again ..

Rob ...
PS, After posting this original question this morning i realised i should have put it in the specific forced induction setion, Sorry about that ....

 

[stevechumo]

I'm using the stock driver manifold, merge to the custom 1.75" on the driver side, combine to a single 2.5" pipe and run to the turbo. The boost seems very responsive at 9 psi with no hesistation. I believe it'll be good up to 15 psi. You may grind the inner stock manifold tubes to make the holes rounder and larger. This will increase efficiency. I just did that but haven't tested it yet.

 

[XR8tt]

I will be using the original flange plate and making my own headers..
Using a 75mm S475 b/w turbo

 

[JustenGT8]

Thanks guy's for the feedback,

Justen how much boost pressure did the engine you saw with 250 rwkw have ?
i would be more than happy with that sort of a figure for my application .. Do you know what other things were done to the engine as in comp ratio, injectors, computers etc for him to achieve that 250 rwkw ...

XR8tt, i agree with you & realise that under boost situation the manifolds aren't quite as critical, but what i was curious about was as to how much they are holding it back by, hence the question if someone had done the standard log manifold option initially, then changed to some better flowing ones, but i am also aware not many would have gone down that route ....

Thanks again ..

Rob ...
PS, After posting this original question this morning i realised i should have put it in the specific forced induction setion, Sorry about that ....

Not a huge amount done and not much of it needed. Some opening up of the combustion chambers and copper HG lowered compression a bit. 7MGTE injectors i think and Haltec ECU. An even 1 bar which the engine takes easily on a good tune.