Big Noisy Extractors and 3 inch exhaust for GQ Petrol Patrol...

They make noise, but not good value sadly.. few threads on OL about it, most say 'it sounds kewl".. but not many really say the power increase was worth it...

but everyone is different.

What's happened to your 'much tuned-up' TD42Ti Patrol???

From the days of my not-completely-misspent youth, extractors usually helped the old Holden and Ford pushrod sixes in both power and economy - but not that much. I'd think that more modern engine designs, with better flowing exhaust manifolds as standard, would benefit even less. Maybe some judicious de-ADR compliancing might do better for the economy department - no EGR, more timing advance and even an appropriate camshaft regrind by someone knowledgeable like Ivan Tighe Engineering in Brisbane??

It's not the extractors that are inherently "big and noisy", it's the exhaust and muffler choices that go with them. The current Ford FPV's and Holden HSV's are putting out GTHO or better power figures with woozy 21st century, near-silent exhaust notes...

Yeah - well because the 4.2 lit never really revs high enough to take advantage of the efficiencies extractors and a free flow exhaust offers you don't notice the difference. If you did plant the foot and rev it - all the time the fuel consumption would skyrocket anyway - not an ideal candidate.

The high revving 3 lit RB30 petrol, on the other hand becomes almost stunningly different with the same treatment and some rocket fuel (IE high octane Premium ULP)

see ya

Nick