4JB1-T timing advancement

[magicdeo]

G'day all, I am considering advancing the timing on my 4JB1-T rodeo and I am wondering if the gains are worth advancing?
Also is reliability sacrificed when advancing timing?
The truck has a 2.5" exhaust and snorkel.
And while i'm here, are the injectors hard to replace in these motors?
Cheers!

[geeves]

If changing complete injector assemblys its not that hard. Cleanliness is very important though.Also you are supposed to change the copper sealing washer in the head. Changing the injector tips would be more fun.
On its own advancing timing will do nothing.It is normaly done at the same time as upping fuel to give that fuel more time to burn. Watch your egts when doing this as too much will kill an engine but otherwise little difference in reliability. Do consider though that hard driven engines dont last as well as more normally treated ones and that those that increase power are the ones that drive to that extra power.

[magicdeo]

Ok no worries thanks Geeves.
One more thing, would there be much difference in power going from a 2.5" exhaust to a 3"? Or would just putting a 3" dump pipe on work well?
I am only new and just realized i am in the engine fault section and not engine modification...sorry about that

[geeves]

95% of the gains come with a 2.5 inch pipe with mandral bends. 3 inch with press bends is about the same. 2.5 inch with press bends is still better than stock with a very strong margin.
In theory you get better economy as well but the cost of a custom exhaust is far greater than any fuel saving even over the life of the exhaust