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Best type of MBC for K-14 turbo/AAZ engine
by
AAZTristar
on 19 May, 2015 11:50
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I want to add a manual boost controller to my AAZ converted Vanagon Tristar truck. I bought a nice ball and spring type boost controller, but while reading some other posts came across a reference that the older KKK K-14 type turbos should use a bleed type MBC. (something about the waste gate needing a flow of air for cooling vs being totally blocked by ball/spring?)
Is this correct? And what would happen if I did use the ball/spring type MBC?
I currently have a Giles super pump, external oil cooler setup, the BOV is blocked, and have a boost gauge that shows the truck running at 11-12 psi max. I would like to bring it up to 15psi for now until I build an air/water intercooler setup.
Also, the truck still has the JX intake manifold from the original engine. Will I be able to use a AAZ intake and still use the JX turbo and exhaust setup?
Any help on these questions will be greatly appreciated!
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#1
by
745 turbogreasel
on 19 May, 2015 23:44
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On my ball and spring controller,I put a dent in the ball seat for the cooling air to leak by. It worked as intended on the first try.
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#2
by
jmaddocks
on 20 May, 2015 07:03
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The bleed isn't for cooling air - it simply enables air to escape the WG diaphragm. Without it, air gets trapped in the diaphragm even as boost decreases, causing your WG to stay open.
I ran a Dawes MBC for a while on one of my cars. It has the bleed valve.
www.3barracing.com
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#3
by
vanbcguy
on 20 May, 2015 07:22
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The K24 does actually have a bleed built in to the wastegate can which is supposed to be for cooling. The K24 also has the wastegate actuator mounted directly to the turbo hot side. Theoretically using a ball and spring style controller with a K24 isn't the best idea, but I ran mine like that for a long time.
The K14 however has its wastegate actuator remotely mounted I believe. That makes the whole thing moot, no cooling is required nor does the actuator have a bleed built in.
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#4
by
libbydiesel
on 20 May, 2015 08:19
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The VW K14s have the same wastegate actuator design as the K24.
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#5
by
vanbcguy
on 20 May, 2015 09:47
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Gotcha. So then yep, it likely has the same bleed setup.
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#6
by
745 turbogreasel
on 20 May, 2015 12:48
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My VAG T3 on the Volvo has the same "KKK" design. Boost control was erratic and spiky till I 'engineered' the leak into it.
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#7
by
jmaddocks
on 21 May, 2015 06:00
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Hmm...I'd never heard about the cooling air before. Learn something new every day I guess.
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#8
by
AAZTristar
on 21 May, 2015 21:40
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Been camping. Thanks for the replies.
So…., to create a bleed path through a ball/spring type MBC I just make an indent in the face of the ball seat? How large?
Any help on the intake question?
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#9
by
745 turbogreasel
on 22 May, 2015 02:34
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didnt take much, maybe like the lead of a mechanical pencil.
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#10
by
RabbitJockey
on 22 May, 2015 04:52
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u can also drill a tiny hole, theres lots of info for it online.