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Turbo with TB's or plenum?
ecosse - 29/1/07 at 11:03 AM

I'm going the turbo route on my zetec and can't find any info on whether TB's are useable with a turbo or if an intake plenum is the best option?
All the turbo info I can find seems to point to using a plenum and single TB, is there a reason for this or is it just becuase this more convenient/available?
Any thoughts/advice appreciated



Cheers
Alex


3GEComponents - 29/1/07 at 11:12 AM

Plenum chamber, like the cosworth, then have provision for another set of injectors, like the RS500

I take it you're going for 500+BHP then Alex?


Volvorsport - 29/1/07 at 11:13 AM

its more convenient to use a plenum and a single TB - throttle bodies - would still need a plenum anyway , might aswell keep it as cheap as possible .

throttle bodies have an advantage on NA in that the manifold design is normally more efficient for power . on a turbo you are force feeding the engine , its not so much of an issue .

plus a single tb isnt so much of a restriction a 65mm throtle plate can easily flow enough air to feed a 4 cyl - since you only have one induction pulse per revolution on a 4 cyl .

lots of older turbocharged cars had twin 40/45s etc , thats essentially a throttle body setup with a plenum attatched . so if you can afford it do it .

places like summit racing in the US sell tb s with an air idle valve and bypass in the tb , perfect for use in that situation , all you need is a manifold an plenum .


ecosse - 29/1/07 at 11:21 AM

quote:
Originally posted by jroberts
Plenum chamber, like the cosworth, then have provision for another set of injectors, like the RS500

I take it you're going for 500+BHP then Alex?


LOL...John, if I get anywhere near half that figure I'd be a happy man

I'm aiming at a low pressure unit with low lag and good midrange, rather than high HP figures and a turbo that takes half a day to spool up!
I prefer usable power to the grenade method of turbo charging

Are TB's pointless/unusable with a turbo then?

Cheers
Alex

Sorry posting at same time there, that explains it better cheers.

[Edited on 29/1/07 by ecosse]


Guinness - 29/1/07 at 01:26 PM

Jambojeef is running a plenum in front of the carbs on his CBR1000! It looks OK and isn't that much more work than a single throttle body or butterfly.

I have heard of people having problems with air leaking out of the spindles on throttle bodies though (under high boost applications). I guess they are designed to run with suction, rather than pressure.

Good luck with the conversion!

Mike


ecosse - 29/1/07 at 05:55 PM

quote:
Originally posted by Guinness
Jambojeef is running a plenum in front of the carbs on his CBR1000! It looks OK and isn't that much more work than a single throttle body or butterfly.

I have heard of people having problems with air leaking out of the spindles on throttle bodies though (under high boost applications). I guess they are designed to run with suction, rather than pressure.

Good luck with the conversion!

Mike


Interesting, I'm gonna make a single TB'ed plenum now anyway, and as I have a set set of TB's ready to go, I might just make a plenum for them as well.

I'll be an expert in plenums by the end of this if nothing else

Cheers

Alex