Extractors & O.S. Exhaust vs standard

snaps,
Put extractors on my 1984 HJ60 2HD motor two years ago, have not seen much/any positive benefit.

bob

Hi Snaps,

I put extractors and a 2 1/2" system on my 1HZ 80 series diesel. It made a noticeable difference to power across the rev range (estimate 5-10%). But I also replaced the original mufflers at the time (10 years old) and they were probably half blocked with soot. Overall I was very happy with the performance increase for the cost.

The 1HZ original exhaust manifold is almost a pipe with a T junction to the exhaust. It is very restrictive compared to many other exhaust manifolds. The more restrictive the manifold, the better it responds to extractors, hence why I noticed a power increase.

It also reved out a lot better. I never had a tacho and after the extractors I put in a chart showing redline for which gear,it reved that much better! It also caused more vibration at idle due to the lack of back pressure (but simply turn the air-conditioner on and it stopped vibrating).

Overall, it was a cheap substitute for a turbo, as I did not want to put a turbo on a 10 year old vehicle.

Cheers

Captain

Gday snaps,Ive fitted Pacemaker extractors and a 2 1/2 exhaust to our 4 Runner(2.8 D).While I didnt notice a great increase in out and out power,it does hold on a bit longer going up hill and sounds alot better to.

in the pre turbo days..

I put extractors and a big (well 2 1/2 inch) exhaust on the 2H, I did this the same week as the snorkel went on, there was definatley an improvement in driveability, and as mentioned above, being able to hold on a little better up hills.

How much was extractors and how much was snorkel I couldn't tell you!

Gday Snaps,
I have 4.2EFI LWB GQ patrol and put Genie extractors on it not long after I bought it, I had a huge increase in low down torque from them, and a bit more power, the economy never changed tho. I left the factory exhaust system on the car untill last year when the muffler was stuffed, so it was a good opportunity to upgrade the system to a Genie hi-flow muffler and resonator and went upto a 3" pipe through out. The dyno for it now shows a totaly flat torque curve with max torque from approx 1500rpm and stays that way all the way to red line, and an increase in power also. The down side I have found is with the bigger exhaust system it seems to have removed any back preasure there might have been by a blocked muffler and smaller exhaust pipe system and tight bends (the guys at genie did a great job of making the bends very flowing). this has reduced my fuel economy by approx 1-1.5mpg on highway trips. no change to fuel economy around the city...

I also changed over to a K&N air filter a month ago away from the Uni filter I had on whch has made a huge improvement in acceleration speed for overtaking in top gear and even better in 4th gear (just got back from kalbarri and overtaking with the car fully loaded with family and gear was very impressive).

regards
Bryan.

I've had a couple of goes.... extractors, larger exhaust systems. They work. Yep 10% - !5% etc. But all that means is that you get 10% further up the hill before you change down gears.... or maybe make to the top. It's not like you put your foot down and get pressed to the seat....... you do need to realize that you only get a degree of improvement... Same with turbo-charging. Yes you can tell a difference. You hang on longer, get quicker pick-up in acceleration, change down later....... but only to a degree. The bus stays the same with a little more oomph. Consider upgrading to a bigger truck?

Hi PerthGQ,
I had the genie extractors fitted at the Genie outlet at Melville. I just got the dyno print out and realised I went from the factory 2" to 2.5" all the way thru not a 3" as previously mentioned.. If you get it done at the factory my dyno readings will be on their computer to compare with what you get... Basicly at the rear wheels I get 100Kw (taken before I changed over to the new K&N air filter) and 271NM torque. I was expecting more at the rear wheels as there is alot at the engine fly wheel going on the factory figures, but with 4wd's we loose at least 35% power and more in torque thru the gear box, transfer case, diffs, drive train,,, and so on, so I am happy with what it actually puts out on the tyres (I also have 265/75 BFG's not the standard 265/70 profile, so I loose a bit more power from the slghtly larger tyres)...
I also changed the leads to the Bosch 8mm induction leads, and have the dyno results that show an increase in power and torque from the bigger spark reaching the spark plugs.. took the power at the rear wheels from 94.2Kw to what I get now, so the new leads made a BIG difference over the original factory ones..
feel free to email me at ccie3106@iinet.net.au if you wannt chat more off line.
I can always scan the dyno print out and email to you to..

regards
Bryan..