[Vwdiesel] boost

[James Hansen]

James Hansen wrote:
yeah, 20 psi is the top end of what you want, and then you want
headstuds, and the multilayer metal gasket. That's too much for
reliability with the stretchy bolts.

Your max fuel screw ultimately regulates the max boost.
Add more fuel and monkey with the wastegate so it opens at higher 
pressure, you get
more boost.  Turbos are essentially a heat engine, so turn up the heat,
it increases the exhaust volume, and you get more work (higher
boost)...until the head lifts off to relieve the pressure.  that's why
high boost engines run low static compression (18:1) so higher boost can
be used without getting combustion pressures so high that the bolts
holding the head on fail.

  -James

> Terry Briggs wrote:
>> 20 psi, I had that in a gasser once, once and then blew the head in 
>> itty bitty pieces. I suppose a diesel would handle the added pressure 
>> being built better. Not having had a turbo diesel I don't know. Would 
>> that be too much boost ?
>> On May 13, 2006, at 10:00 PM, Shawn Wright wrote:
>>
>>> On 13 May 2006 at 20:54, mikitka <mikitka at earthlink.net> wrote:
>>>
>>>> Well I went and adjusted the boost on my 91 ECO with the K14, to my 
>>>> surprise I
>>>> got 20psi boost from it.  I still have smoke so I guess I need to do 
>>>> some
>>>> adjustments. My timing is set at 1mm and the injectors are good.  I 
>>>> can say this
>>>> much, that 1.6 really pulls, especially when the boost hits 15psi.
>>> 20 psi! Wow. Do you have a blow-off valve on the intake manifold? My K14
>>> maxed out around 15 once I wound the blow off valve in all the way. What
>>> rpm do you get 20psi at? I'm surprised, as even when running with no
>>> exhaust (18" long 2.5" pipe) and 3" intake I never saw more than maybe
>>> 15.5 psi on a long climb. I haven't touched the wastegate yet...
>>>
>>>
>>>
>>> Shawn Wright
>>> http://members.shaw.ca/vwdiesels
>>> '88 Westy 1.6TD 5 speed
>>> '85 Jetta Diesel 1.6NA
>>>
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>>
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>