You could try fitting tubular manifolds.
Or porting & polishing your existing ones, but if you're looking at improvements then you need to consider doing all the ports - inlet & exhaust.
Fitted a stainless sports system with tubular manifolds to my 3.5EFi years ago but apart from the noise - nice, but can get a bit tiresome on long journeys - I'm not really sure it made much difference.
Or porting & polishing your existing ones, but if you're looking at improvements then you need to consider doing all the ports - inlet & exhaust.
Fitted a stainless sports system with tubular manifolds to my 3.5EFi years ago but apart from the noise - nice, but can get a bit tiresome on long journeys - I'm not really sure it made much difference.
norseman
Well-Known Member
Assuming you have a 3.5, changing the camshaft to a 3.9 item is allegedly good for 10% more power, but I would imagine the torque (curve) is more important on a heavy 4x4.
Generally speaking success in creating more power means a package of improvements rather than a single modification. Bolt-on gizzmos have their limitations
Generally speaking success in creating more power means a package of improvements rather than a single modification. Bolt-on gizzmos have their limitations
discool
Well-Known Member
The manifolds all appear visually to be the same with 3.5 or 3.9 a cast lump of metal.
The EFI ECU that the 3.9 has wont like the alteration so it and will re-adjust… maybe.
12 years ago I fitted a Janspeed cat-back system to my 3.9 and on first startup the engine went up to 2000 rpm and sat there for two minutes, the ECU thought about it, and then rpm dropped straight back down to the normal 750rpm.
With the exhaust replacement was an instant improvement to the throttle response and and a bit of a change to the exhaust tone, thats it.
Cool - looks like it'd be very small gains for potentially big upset, so I'd best leave it alone then.I had been thinking on sportier exhaust manifolds and or Thor inlet manifold:
But in light of what's been said here I've decided to leave it alone, and instead ordered Rover-Gauge / ECUmate set up and an ignition upgrade kit comprising of a MSD Mallory Uni-Lite transistorised distributor, the matching fancy MSD highpower coil and a MSD Street Fire Capacative Discharge Ignition module. That way I've got a right good spark and can play with the ECU
But in light of what's been said here I've decided to leave it alone, and instead ordered Rover-Gauge / ECUmate set up and an ignition upgrade kit comprising of a MSD Mallory Uni-Lite transistorised distributor, the matching fancy MSD highpower coil and a MSD Street Fire Capacative Discharge Ignition module. That way I've got a right good spark and can play with the ECU
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hef19898
Well-Known Member
Might be a wise move, esp. if it's an EFI
Best improvement I am aware of (by an indie. mechanic on his own 3.5efi auto) was to stroke the lump to 4.3L using a kit from a company called Real Steel, but I don't know if they are still trading.
That sounds interesting! More power is always a good thing, and I have no interest in reboring an otherwise perfectly fine engine block!
norseman
Well-Known Member
That's what LR did to produce the 3.9 & that was the beginning of the slipped liner syndrome
The downside of the 4.3L mod. is that the output is close to (or possibly over if you have a heavy right foot) the standard ZF 'box's handling capacity.
