Hay all. I'm looking at extractors for a 3.5l auto verada. I'm looking for an improvement in low to mid power were the 4sp auto lacks. Witch would help I guess with econemy. What are people's thoughts on an extractor to suit this?? Thanks kurt

I'm practically a sales rep for HM headers after fitting HM headers to my Magna. Its my first set of extractors so I have no experience to measure my opinion against though. I just know the car "feels" much stronger in the mid range and sounds freakin' beautiful. Improvement over standard? HELL YES! But, improvement compared to pacemaker or Xforce I wouldn't know.

Build quality of these things seems excellent to. They've been on the car for around 3000km now at a guess. No problems. No cracks, no leaks and no clearance issues.

I think hm are the only ones with the flex in the Y pipe to help stop them cracking. Have a bit of a search, there have been header choice threads before.

How is fuel economy effected after fitting extractors?

Once you get over the honeymoon period (of having awsome sound and midrange) and settle back into normal driving, fuel economy does show some improvement. Nothing astounding, half a liter here a quarter liter there. But no dramatic improvement. Not in my case anyway.

My honeymoon period is on again, off again....

HM supplied the ralliart ones IIRC

Question is are these extractors good for the 4sp autos witch need low to midrange punch. I thought these hm headers were designed for the ralliart witch was for top end power? And is there actually any gain in fuel econemy?

Question is are these extractors good for the 4sp autos witch need low to midrange punch. I thought these hm headers were designed for the ralliart witch was for top end power? And is there actually any gain in fuel econemy?

ANY extractor is going to move power up over a standard magna header. The HM do this less so and have more midrange then the rest.

I have a four speed and both it and my engine are much appreciative of the mid-range punch the HM's deliver.

Improvements in fuel economy? Marginal. Sometimes its there. Highway economy is amazing. But I think it'd take more than extractors to boost the economy of a six cylinder car driven in traffic. Just enjoy the sound and little extra grunt.

As for pipe design... my thinking tells me shorter primaries are used for higher RPM power, and longer primaries were for low/mid rage power. Not sure why or how but popular consensus says the opposite. Maybe they used the HM's to iron out (flatten) the torque curve of the Ralliart so it didn't scare some cardigan wearing tool. That or to meet a noise pollution rule or for clearance. Or for price (lowest bidder)?

ANY extractor is going to move power up over a standard magna header. The HM do this less so and have more midrange then the rest.

Wat u mean hm do this less so? Less than other extractors

Wat u mean hm do this less so? Less than other extractors

If you make it easier for the air to escape from the engine it is going to gain power and usually this is in the top range, Hm do this as you would expect but also give more midrange then other extractors.

Is it still a 2 1/2" outlet from the extractors? You dont need a bigger bore exhaust to suit?

If you make it easier for the air to escape from the engine it is going to gain power and usually this is in the top range, Hm do this as you would expect but also give more midrange then other extractors.

Tuning the length is more important that bore on an NA engine.

2 1/2 inch on these engines is plenty.

If you make it easier for the air to escape from the engine it is going to gain power and usually this is in the top range, Hm do this as you would expect but also give more midrange then other extractors.

Cheers