Which exhaust

Hi there everyone. Was wondering if you could share your thoughts on which exhuast i should choose? Looking at a 2-3/4" from Beaudessert exhuasts, a 3" from Roo system or a 3" from Taipan to suit my D40 manual navara. Everytime you speak with either one of them they always say there's is better. The most common thing i hear is that the 2.5 ltr engine doesn't gain any extra power or fuel economy when using the 3" exhaust.
Would love to hear some feed back form you all if possible. Thanks Blacky

hey mate ive heard mixed reviews on all those you have mentioned. i do not have a d40 however if you want to save a few more bucks maybe try Scotts Rods in West Ipswich. they post anywhere and are competitive in pricing. im hoping ot go there and get my dump pipe done by them once they reply back to my email.

as for gaining power im not sure. youll get better low down torque better feel on the throttle and the next thing after an exhaust is the chip.

good luck
Rusty

Ridgie has a roo systems exhaust on his d22, Maybe send him a pm and get his opinion, He put a few posts up about it from memory i dont believe it was all roses

Thanks guys please keep your thoughts coming. Dave i'm pretty new to this will try to send message to Ridgie.

IMO - I reckon they all do about the same job. Which kind of makes sense when you think of what they are trying to do in aftermarket supply...... (non-technical info below):

Wider exhaust and less bends (esp from turbo back) will mean greater flow of exhaust away from engine which will mean it will spool up quicker with less exhaust restriction.

When I put a 2 3/4 Beaudesert on str8 thru on mine I lost that exhaust break feel you get when you lower down thru your gears. But it spooled up quicker and turbo seemed to kick in a little quicker as well. Also sounds like more air getting sucked into thru snorkle. Fitting wise, the Beuadesert wasn't too hard to install on mine.

Did it seem like more power? Not huge - I think you'll find to get more power out of these you'll need CPU map + exhaust + more air in (turbo or charger upgrade) and thats a very different story

If all three brands are equal size, are mandrel bends and about the same price, then I don't think there's much between them. I'd go off which ever dealer you feel comfortable talking to, getting a good price in comparision to the others available and any comments on how easily they fit up.

Hope some D40 owners offer opinions for you. Be sure to lok thru other threads as well as I'm sure this is covered elsewhere.
http://www.navara.asia/d40-engine/4649-beaudesert-exhausts.html
http://www.navara.asia/d40-engine/9539-exhaust-systems.html


cheers

I emailed Scotts rods re their different ones, they know their stuff, different dump pipes for the different models, got a fast response to my questions, seems like a good thing.

I have bugger all experience with Navara's, however all Turbo engines are the same when it comes to exhausts.

After the turbo, other than stopping rocks from falling into your snail, the exhaust pipe is only there to get the fumes and heat out from under the car, BIGGER is better, no exhaust at all would be the ultimate for power, a turbo diesel has no requirement for any form of back pressure, only NA engines need this, obvously there is a point when going bigger makes no difference or improvement in power, however, with late model stuff fitted with DPF's and Cats, the size of your system wont make much difference if there is a blockage in the pipe, which is what a cat is, it restricts the flow of gases to increase the temp of the cat so all the nasties are burned inside, good for the enviroment, BAD for power, bad for fuel economy.

If you wan a cat in your system to stay legal, buy a good 4" metal cat, they are much less restrictive (you can see through them) and flow heaps, put this in a good mandrel bent 2.5" (min size) or 3" (best) with good high flow (straight through) mufflers, and this will allow you to stay legal and not slow you down at all.

I have a 3" mandrel bent, 4" metal cat, one high flow straight through muffler on my cruiser, it is great, HUGE increase in power, better fuel econ and almost instant spool up of the turbo.

I have also used the same set up on turbo falcons, I know, not a TD, but a 4 lt engine, running to 6500 rpm, punching out 350kw at the back tyres, over 420kw at the flywheel with over 1200nm of torque with a 3" System and 4" metal cat, if it can flow enough for that, a 2.5lt TD wont even go close to stressing it.

I have not looked under the bonnet yet, but I dont think the turbo has a wastegate, so a HUGE dump pipe wont make a lot of difference but remember that the gasses coming out are very hot, hot gasses expand and need lots of space to go away fast, so even if you only want a 2.5" system, I would use a 3" dump, onto the cat, then drop down from there if you like, as the gasses cool, less room is required.

Good Cats and mufflers are what you should be looking for. buy the best you can get.

Chris C when you mentioned About a 4" metal cat do you mean inlet and outlet size or body size. cause the body size of a 4" cat is 5". Where as a 4" body is only a 3" inlet and outlet. any ideas cause im gonna do this when I get my dump installed.

cheers
RustyNav

RustyNav09 said:

Chris C when you mentioned About a 4" metal cat do you mean inlet and outlet size or body size. cause the body size of a 4" cat is 5". Where as a 4" body is only a 3" inlet and outlet. any ideas cause im gonna do this when I get my dump installed.

cheers
RustyNav

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Sorry, should have been more clear, yes, a 4" cat, is body size and will normally have 3" inlet and outlets, allthough there are many different types out there now, I have a 4" cat on my Cruiser that is 4" in and out, straight body, 4 hole flange on each side and flows like there is nothing there, but is street legal. it all comes down to how much you pay.

The lower end in flow/quality cats (factory) will be bigger in dia to help with flow, the one fitted to the 150 series prado is 190mm (7.5" ) od, with 2.5" inlet and outlet, but still wont flow like a good 4" metal cat will. They just create more heat and back preasure, both the mortal enemy of a turbo engine.

Alright that makes more sense. They aren't that pricey looking at eBay prices. But I am not sure how you bolt a 4" cat to a 2.5" pipe/flange. Lil confused. Obviously the exhaust guys will know but I like to make sure its done properly.

thanks a lot everyone, went and spoke with my local exhaust guy and he thinks he can build me the same mandrel bent exhaust and a little cheaper.
Hopefully will be getting it fitted next week, will let you know if or how much fuel i save and if it goes better. again thanks for the feedback.

Blacky said:

thanks a lot everyone, went and spoke with my local exhaust guy and he thinks he can build me the same mandrel bent exhaust and a little cheaper.
Hopefully will be getting it fitted next week, will let you know if or how much fuel i save and if it goes better. again thanks for the feedback.

Click to expand...

Just have a read of this thread too.
3" Exhausts and low RPMs