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Old 25-09-2017
awg  awg is offline
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Quote:
Originally Posted by kyphonii View Post
So I am looking in to the age old problem.
Do I upgrade or rebuild.
Upgrade to what. (XJ check all my box's for an off roader).
or
Rebuild a XJ and run it for another 10-15 years through retirement.
If you rebuild a 4L what to do to it to improve it.
I run 90% of the time around 2000rpm. I don't want any increase in power above 2000rpm or increased fuel consumption. Working up a bit more torque around 2000 if possible with out going to premium fuel.
Cheers
Interesting question

from my basic knowledge of engine building theory, there isnt a lot you can do to increase power at lower RPM, apart from (maybe) a different camshaft, but more importantly, an increase in stroke

To the limit of my theoretical knowledge, most improvements work across range or at upper end, some even at the expense of low-end response..ie increase flow (alone) for more power will usually make idle & low-end response worse.

The white one I have with headers and big exhaust seems to have more power, but once again, in theory, this would be mainly (or all) at above 2000rpm

how many kms does your unit have on it?
__________________
'96 4.0 Sport 370k+
'96 Limited 263k (unreg spare)
'96 Sport 335k (got smashed, farmtruck)