[xj-s] Porting & Polishing

Wayne Estrada wrote:
However porting and polishing

(and cc’ing) is an old hot rod trick and I can’t see why that should not help
on the mighty Jaguar V-12.

Wayne Estrada
1989 XJ-S Convertible (Dorchester Grey)
1989 Vanden Plas Sedan (Alpine Green)
Richmond VA, USA
Please Visit my Jaguar Site at:
http://www.u3training.com/jaguarwww.u3training.com/jaguar

I think the BOOK says it won’t help on the HE because of the design of
the combustion chamber. No room to breath or some such. I am sure Kirby
will have more to say. Or maybe he said enough in the BOOK?

Robert
73XJ12

GTJ offers porting and polishing. Evidently the intake side of the cylinder
head is actually an angled design that promotes turbulence on high
acceleration. Much like the stock throttle bodies but to a lesser degree.
GTJ says they ‘port’ this which creates a wider opening and eliminates the
angle with a more radiused opening. They do something similar to the
exhaust side as well. Obviously they’re trying to gain business. Is this
something the list feels worthwhile?

Also, when you goto the AJ6 induction and if you also change the exhaust, it
has been recommended to modify the cams to allow for increased open & close
times for the intake & exhaust valves. Essentially your sucking in more air
but the existing cam isn’t designed to handle it optimly. Is this
something worthwhile to consider as well, or are we approaching overkill
with these concepts?

Curious by nature,
David Kowal
'86 XJ-S

At 06:23 PM 3/24/99 -0500, David Kowal wrote:

GTJ offers porting and polishing.�
Also, when you goto the AJ6 induction and if you also change the exhaust, it
has been recommended to modify the cams to allow for increased open & close
times for the intake & exhaust valves.\

David:

This is not what both Paul Wickre of Radford Engineering (USA AJ6 Distributor
301-718-3562 ) and Roger Bywater of AJ6 say. To my knowledge, the AJ6 mods
would work adversly with modified cams because the ECU must be reprogrammed to
allow for different valve lift and duration. However porting and polishing
(and cc’ing) is an old hot rod trick and I can’t see why that should not help
on the mighty Jaguar V-12.

Wayne Estrada
1989 XJ-S Convertible (Dorchester Grey)
1989 Vanden Plas Sedan (Alpine Green)
Richmond VA, USA
Please Visit my Jaguar Site at:
http://www.u3training.com/jaguarwww.u3training.com/jaguar