Extractors - Will they have any noticeable gains?

[Pablito]

Hi

I'm driving a
1985 BJ73
3B diesel, non-turbo

I popped in to a mechanic to check an exhaust leak. He said its somewhere near the manifold, and to find out exactly what the problem was he would have to take it in to his workshop. He said minimum $200 (Australian dollars) - if its the gasket, may be double if the manifold is cracked.

I can get extractors off ebay for $400. The ebay ad says "great horsepower and torque gains"
The muffler mechanic thought extractors would be beneficial.
But my mate says no I won't get any increase in power etc.

Anyone have any experience or thoughts???

cheers,

Paul

 

[clivehorridge]

I have no experience on this engine, but it's a fact that "extractors" do improve exhaust efficiency so it's inevitable that some improvement will be made, just how much... others on this site may be able to tell you...

Moons ago I had a mini 1071cc "S" stage 2 tuned and that had a long centre branch exhaust (LCB) 'extractor' and the before & after difference was very noticable, but maybe that was because it was a tuned engine (modded cam, in/ex ports, compression, DCOE Webber carbs etc...) sigh, those were the days...

 

[Paddler Ed]

Hi

I'm driving a
1985 BJ73
3B diesel, non-turbo

I popped in to a mechanic to check an exhaust leak. He said its somewhere near the manifold, and to find out exactly what the problem was he would have to take it in to his workshop. He said minimum $200 (Australian dollars) - if its the gasket, may be double if the manifold is cracked.

I can get extractors off ebay for $400. The ebay ad says "great horsepower and torque gains"
The muffler mechanic thought extractors would be beneficial.
But my mate says no I won't get any increase in power etc.

Anyone have any experience or thoughts???

cheers,

Paul

I got a new exhaust and extractors on my FJ73 over there; it came to around $700 fitted. Ended up with 2.5" exhaust and it felt a bit better and ran nicely with a nice bit of noise.

I seem to remember 4wd action did a bit on the most effective ways to get power gains, and the new exhaust and extractors was a reasonable solution.

If you can get it mandrel bent rather than crush bent; unfortunately people like Beaudesert Exhausts don't do kit exhausts for 73's (or at least they didn't in about Feb this year) so it's a case of trying to get it sorted by a workshop rather than DIY.

Hope that helps,

 

[wobbly]

Forgive the ignorance - but what is an exhaust 'extractor'?

Pete

 

[Chas]

Forgive the ignorance - but what is an exhaust 'extractor'?

Pete

It's a big fan you fit on your tail pipe. only joking, I don't know either.

 

[andyw]

Extractors are a custom made exhaust manifold, read http://en.wikipedia.org/wiki/Aftermarket_exhaust_parts

 

[wobbly]

AAhhhh - we're talking Headers!

Now I understand, ta,

 

[Chas]

Thanks Andy.

 

[Paddler Ed]

Headers/Extractors/Exhaust Manifold are all pretty much interchangeable... whether it's correct or not is another matter!

The big difference with the aftermarket stuff is that they endeavour to get the lengths all the same, and the bends to be mandrel rather than crush bent. This all means that the pressure is more even and consistent, and the flow of gas is better with fewer restrictions.

Ultimately all of that makes the gas escape quicker, removing the used air from the engine quicker so that it burns with better air.

The other one that makes a difference in Aus is the use of a snorkel; the air that is higher up is cooler (therefore denser) and cleaner (less dusty) so that results in the air filter getting less blocked up (more good air getting in) and a higher oxygenisation so a better burn in the engine. Whether it makes as much of a difference over here I'm not sure. They found on a HDJ80 IIRC about a 1.5l/100km improvement with a headers and a snorkel compared to stock.