b.benz at charter.net
Fri Apr 4 08:35:05 PDT 2008
An ill-considered mod IMO, unless one is only interested in top end
power and no cares about fuel economy and smog approval. Using, just
slapping in the 7A exhaust cam will advance the valve timing,
favoring top end power at the expense of low end torque. Further, it
will increase the 3B‘s zero valve timing overlap and allow turbo blow
thru degrading fuel economy and smog.
On Apr 4, 2008, at 7:32 AM, Brandon Rogers wrote:
> Plenty of people use the 7A cam(s) (exhaust I know - not sure about
> and make good power - IIRC dyno result show top end increases but
> low to mid
> decreases. To convert the 7A you will want (need) a compression
> head gasket. Tons of info on Motorgeek.
> On Apr 3, 2008, at 4:04 PM, Tom Egbert wrote:
>> How is your son planning to mod the 7A's valve timing to reduce or
>> eliminate the NA's valve overlap, such that the turbo can't just blow
>> I am not sure, but a spare 3-b head modded for coolant flow should
>> take care of that. I am more interested in my 200 20v getting 24
>> pounds of boost reliably.
> The 3B and AAN heads have the 4 outlet external coolant manifold. The
> 7A does not, just a single outlet.
> Ask him to respond with his valve timing mod plans.
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