Outer Limits 4x4 Board

Question? I have a 4.2 diesel shorty has anyone put extractors or an exhaust system on theirs? was there any power increase? does it sound cool?

4.2 diesel engines - ive heard people say that extractors have given the car bugger all power increase... and you're better off savin up for a turbo setup as its only a quarter of the cost of the exhaust.. so may as well keep on saving...

to give you an idea.. a GU factory turbo setup is a straight bolt up to a GQ with some mods to water and oil lines, and they can be had cheap.

THEN fit a nice fat 3 inch pipe behind it

sounds cool, very loud if ya get a good muffler. dont expect more than about 2% power increase. but fuel economy is a little bit better. but you do lose a little bit of compression braking.

the reason i ask about the power increase is because i can get the whole system extractors and all fitted for $550 or just a bigger pipe for $220 i'm really after just the sound and to reduce the size of the muffler if have one at all.

mickey,

how the hell did you work out that it gave you a 2% power increase? I mean, lets assume you got a good one and it made 75kw on the dyno. Plus 2% is 76.5kw. That could be had with change in air intake temp.

I am assuming that you are guessing when youu say that then...

I have a mate that fitted a 2.5" straight thru system with extractors onto his 94GQ, and it went a fair bit better than stock, with better economy too. Only issue was it droned at 80-110. I couldn't stand it personally.

I have a 3" system straight thru on my GQ with turbo. It made a fair difference to the seat of the pants o-meter and gives a great note. Original system was 2.25 on my car.

Andrew

coke wrote:mickey,

how the hell did you work out that it gave you a 2% power increase? I mean, lets assume you got a good one and it made 75kw on the dyno. Plus 2% is 76.5kw. That could be had with change in air intake temp.

I am assuming that you are guessing when youu say that then...

I have a mate that fitted a 2.5" straight thru system with extractors onto his 94GQ, and it went a fair bit better than stock, with better economy too. Only issue was it droned at 80-110. I couldn't stand it personally.

I have a 3" system straight thru on my GQ with turbo. It made a fair difference to the seat of the pants o-meter and gives a great note. Original system was 2.25 on my car.

Andrew

i didnt work it out, i was simply saying expect f***k all power increase. it may be as much as 10 or 15 % i dont really know. but it certainly doesnt turn ya truck into a speedway demon....... i am happy with my extractors, and thanks to a little deal i did they cost me SFA. if ya gonna get them make sure there mandrel bent extractors and a mandrel bent custom exhaust would be good too. on my ute, the way the exhaust pipe was run it is preety well straight with minimal restriction, but i dont know how youd go on a shorty.......you have to see it to understand what i mean, ill see if i can get some pics

Coke do you think its worth the extra money for the extractors?

matto wrote:Coke do you think its worth the extra money for the extractors?

see my post above about the mandrel bender

mickey,
If you dont mind me asking where did you go and what price are we talking about

matto wrote:mickey,
If you dont mind me asking where did you go and what price are we talking about

mine was done at a midas outlet, the price they quoted me was about $700.00, for mandrel bent genie extractors and a 2.5" exhaust with a "sports" muffler. but i would rather a turbo with a 3" exhaust

The extractors I mentioned were on my mates car. I would get them if that is the direction that I was heading (non-turbo) but I would put a hotdog in the system to shut it up a bit.

Agree with micky about the mandrels. I have a full mandrel system and it does make a difference. Even get mandrel bends if you are getting a 2.5" system. The small extra cost (maybe $100) is worth it. gases flow much better...

Andrew

i put on a set of extractors and 2.5 mandrel exhaust with one straight through muffler on my GQ swb, it sounded great, not too droney and made a marginal increase in power, but it could have been the tuff noise making is feel faster, it was a bees dick faster really. id just go the 2.5 system withone staight through muffler, and spend the other few hundred on some else, UHF,towards a locker, whatever. but its up to you of coarse

Most engine builders would say the power increase would equate to about 1/2 a gear.

I use a program called Engine Analyser Pro and by changing the factory manifold with free flow headers with 2â€

GutSquisher Media wrote:not much but when you are talking about a motor that produces 85Kw adding 3% is better than nothing.

I may be the only one here, but I don't necesarily agree with that. Dollar for kw value, you are far better putting a turbo on the car.

Outlaying $600 plus for 2kw is a waste. You would gain more than that by changing your gearbox and diff oil for some expensive gear (redline or similar) and regreasing everything with a good hitemp grease. I have seen oil changes with $100/4lt oil add up to 10kw atw in a WRX. You would be amazed what a good lube will do.

Oh, and also fit those wind deflectors to your front windows, and headlight covers. TIC

Andrew

coke wake up and smell the roses, have you thought that he hasn’t got the $2500 to $3000 to send on a turbo.

Were not all as rich as you and some people need to think about what they can afford to spend.

set ur motor up for straight gas, leave ur standard exhaust manifold unless cracked and get a 2 1/2 inch free flowing one muffler system. i have this but i have extractors too. get good tune done to suit straight gas and u will have a very healthy patrol..

if extractors and exhaust give 10% increase, the extractors will be worth only about 2 of that 10, with the exhaust being the rest. use the 350-400 u save to get a straight gas mixer and u will be more happier with the performance gains

viperguy wrote:set ur motor up for straight gas, leave ur standard exhaust manifold unless cracked and get a 2 1/2 inch free flowing one muffler system. i have this but i have extractors too. get good tune done to suit straight gas and u will have a very healthy patrol..

The lack off LPG availability in small towns makes straight gas a bit of a worry for me personally. Even if I rarely ever use petrol, its kind of an emergency fuel really.