the top of the line BNR rebuild for a s4 turbo work for use on a 1/2 bridge? i cant find any posts about people using it to make an kind of decision. as most questions for BNR stuff is third gen related.

 

no one ever put these two things together?

 

That will not work. Too much turbine restriction.

 

^^ what he said.

Although, it'll work, you won't be getting the full benefits of the half bridge. The turbine is too restrictive. You may end up blowing the engine due to too much exhaust reversion pre-igniting your incomming intake charge (if anything, the dilution will kill power). You'll most likely have HUGE problems keeping boost control also. Hybrids have trouble as they are with boost creep, through in the breathing abilities of a half bridge and it will make boost creep even harder to control. If you want a hybrid, stick to a street port. If you want gobs of power, half bridge it with a LARGE turbo.

~Mike..........

 

the mazda factory used 2 ht-20's on their full bridge motors, because 1 turbo created too much backpressure in the exhaust.

an s4 turbo is an ht-18

this is sourced from the fc yamaguchi book, the engine also appears in the racing beat bonneville fc.

 

could i then techniquelly use two turbos....

 

technically, yes, but by the time you got it to run right you probably could have set up a large single system.

 

my biggest enemy is cost of a large single. im may just go ahead with a streetport setup and pursue this endevor down the road sometime.

 

if your talking about the st3 bnr rebuild with full t4 turbine, it works fine. ive done it on full bridge port with custom manifold. it made plenty emediate power, ive since upgraded my turbos, not because i wasnt happy with the performance but just more curious how much more power a larger tubo would make.

I think the gains from the bnr st3 or similer with full t4 turbine and 60 trim compressors are hard to match. i make more power now with more boost on larger turbos, but its all realative to money spent, and power gain with simpicity and minimum cost of the high flow type are second to none.

but i do think a street port will be a better match to this turbo.

 

thats more like what i was looking for. im wasnt planning on doing a riduluos 1/2 bridge. just a mild one you could call it.

 

that will work great! just be sure to get the st3 option with p trim wheel, and larger swingvalve fitted, i was able to hold .4bar with stock actuator, i then fitted bleed tape to bring the boost up to .7bar this is were the fun started.

 

how much did they charge you in total? they are only like 2 hours from my house so i can just drop it off.

 

i had mine done localy with a garrett core. same thing really just not by bnr. it would have work out to aprox 600us with machining and and new t4 garrett core.