Extractors???

Hi Tom,
I have extractors on a '79 rangie.
My motor has done over 500K klms and it's very tired!!
The extractors were on the car when I purchased it (16 years ago), so I can't compare!
But it does feel better on up hill climbs, maybe not more low down torque ( I can't feel it)
But definitely better consumption!
I used to get 6.5-7.0 km/l at 100kmh criuse.
The rangie I compare it to, had a better condition motor ('80 model), but on the same criuse could only manage 6km/l!
The standard rangie exhaust looks too restrictive, but I think gave good low down torque, and quiet!
Only problem with my extractors they gave a louder (than I like) rumble.
The std rangie has the best exhaust note :)

hope this info helps!

I put extractors on my 96 GQ diesel and felt an instant difference but then you lose the feeling as quick as you get it because you get used to it....
I then took the extractors off so a turbo could be fitted and felt a difference that didnt go away....
I have those extractors if you are interested...gqpatrol at bigpond dot net dot au

Extractors do help the engine breath better, so more power.

Hope this is not too basic for you. Ignore any bits that are.

Now there are extractors and extractors. Some are just free flow and some actually work properly. Basically the idea is that the primaries are the right length so that the gases from one cylinder pass the end of the pipe from the next firing cylinder just before that exhaust valve opens, and creates a low pressure in the exhaust just behind it, thus helping the next cylinders gas to come out, or extract :-).
So the design (length & dia) of the primary pipes are important. Also, as few bends as possible and bigger radii also help.
Next are the secondary pipes. These are the pipes after the primaries (!!!) and the length of them tunes the point where the power is. Longer secondaries gives you more torque down low. That is longer than the ideal length for that engine.
The loudness of the exhaust is decided by the exhaust system and the muffler.
Of course, if you are after more power you will need to keep the exhaust free flowing (you already have gone to 2.5" pipe for that reason) so that the engine is not using power to pump the gases out of the end of the exhaust pipe. So most people with extractors go for a muffler that doesn't restrict too much, the result is some more noise. The choice is yours. And there is a huge range of mufflers and a science to them as well :0).
An old bloke told me that if the outlet tip of the exhaust is the same dia as the exhaust port, this gives you the quietest exhaust. You can have more than one outlet, and I am sure you have seen the twin pipe rear mufflers. One to think about, and makes you wonder about those 4" and 6" dump pipes that seem so popular on ricers. They increase the noise. So a large exhaust doesn't necessarily help, large as in 3" and more, depending on engine capacity.
Quality of welds and the way pipes match to each other also decide if you loose any power in the system. If there is a ridge of blob of weld on the inside, it creates more turbulent flow in the exhaust, and the engine looses power. Also, matching of ports is important. If the hole of the outlet port doesn't exactly line up with the extractor primary, there is a ledge and power is lost. All theses are small power losses, but they add up. And this is the fiddly part in making extractors, getting them just right, and fiddling costs money. But some people charge more to make it seem a dodgy set are a good set, and some charge more because they do make a good set.

Ask around on this forum and other nissan owners may be able to recommend different makes.

I fitted Pacemaker extractors to my GQ before the turbo, and extractors did nothing but make noise.

others will tell you they gained 200124092830498 kw at the key, but yea, the bloke I sold them to also said they did nothing.. he too saved the $ and went turbo.