Extractors V's fuel economy / power

[Patrol 1993]

Hi Guys,
I have a 1993 Patrol with a 4.2 petrol engine, it has done 200,000km.
Would putting a set of extractors / headers on the exhaust system help with fuel economy and power?
Or is it best to change the whole exhaust system?

Thanks.

Neil.

[Parksy]

Every little bit helps, but if you're going through the trouble of fitting extractors, you're better off going the whole system as the stock form is very restrictive.

[krbrooking]

X2 as above. If finances permit do the whole system, I would also get a tune done after as well which will also help.

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[Patrolling Paddy]

Headers will help as long as you avoid the right foot as it the sound will be better and most of us have a tendency to give it a squirt due to the nicer note.
Make sure you pick a set of headers for the type of driving you mostly do.
For more low-mid driving a different design to full rpm racing will be required. Don't be tempted to go the bigger is better ideal as it won't be. Have a chat to a couple of exhaust shops and see what the common recommendation is. Explain to them what you want and let them recommend a system to suit, after all it is what they do for a living, they will sell you anything if you tell them that you want size so and so.

I would be thinking a 2 - 2 1/2 system with a decent free flow muffler to suit the desired volume, just allow for drone when cruising and pick an appropriate muffler setup to avoid it.
Probably something around 1 1/4 - 1 1/2 primary pipe size should be about right.
Use that as a guide only as I am not an exhaust expert by a long shot

[billyj]

i had pacemaker extractors with a free flowing 2.5" system on my tb42e before i went turbo, the extractors and exaust definetly helped with power and economy my best figures were 13l per 100km on a freeway run between werribee and sale while fully loaded. around town expect about 20l per 100km. you definetly need to fit a decent cat back to go with the extractors as the std system is quite small and restrictive.

[mojo53]

I got a Turbo upgrade on my 2006 Y61 TB42 from United Fuel injection in Perth WA and they insisted i upgrade my exhaust to 3" and believe me the combination was absolutely amazing, i did change the exhaust to 3" before doing the Turbo upgrade and that alone made an impressive change...size does matter lol