View Full Version : Exhaust upgrades...any benefits?

09-01-2009, 03:22 AM
Hi Guys,

I was talking to a guy in Coffs Harbour while I was away recently and he was on about upgrading the D40 turbo's exhaust system. Now I know the high powered turbo cars like Gtr's and the like upgrade thier systems and they seem to benefit from this but is there any benefit in upgrading the D40 system?
Does it make more power? Is it more fuel efficient? etc. Has anyone considered or made this change? If you have what parts have you used? How much did it cost and how big did you go?
DOES SIZE MATTER......:5: anyway, look forward to hearing from you.

09-01-2009, 05:11 AM
i'm looking at doing it in the next couple of months to my d40. going 2.5 inch . supposed to give more power and better fuel economy especially on long trips which i do quite often.been quoted $1100

09-01-2009, 05:55 AM
Have you guys had a look under your D40s, the last few I've looked under have had 2.5" mandrel bent systems from the factory, if yours are the same about all I'd consider doing is changing out the muffler for a straight through job, or if you don't mind a little extra noise, just a piece of pipe in its place.

09-01-2009, 06:52 AM
Hi Shonky,

thanks for the heads up. I haven't looked but will do once the wife brings back the car...she loves driving it.

Anyway didn't think thing happened from the factory. I will have a look and let you know.....
thanks again

09-01-2009, 07:00 AM
It's pretty common now with all the new diesels in the utes, the D40 Nav, the 3.0 D4-D Hilux, the 3.2 DiD Triton, and the 3.0 BT-50/Ranger that have all passed through my work for fit ups in the last 6 months have had 2.5" mandrel bent systems on them out of the factory.

09-01-2009, 07:16 AM
Hi Shonky,

just had a look, looks like its mandrel bends from engine/turbo to the muffler then press bends from there onwards. Its good to know that they have done this from factory.

So if this is the case its just a simple case of replacing the muffler with a straight through and end pipe to mandrel bends 2.5 inch.

Thanks again

09-01-2009, 07:26 AM
i now have a 2 3/4 mandrel bent system on a 2006 d40 auto, pretty sure factory system was only about 2 1/4 and defintly not mandrel bent so the bends where restricted even further. some small economy benifits noticed straight away and definitly a power increase. i had the car on the dyno before and after the dp chip. hopefully i can get it done again soon and get some real figures on the power increase for the exaust as i could not find any when i was looking for a system. i am pretty sure that the system cast around $1250 fitted. value for money i would go a DP chip first as i recieved a 25% increase in power on the dyno and it dosent use any more fuel if you drive it normally. however when you nail it all the time to see how much better it goes it sure usses a crap load of fuel. the bonous with the chip is you can easliy take it with you to you next diesel vehicle so long as it is a common rail injected diesel.

09-01-2009, 02:06 PM
im thinking of just cutting my exhaust back before the muffler.. see how it goes.. if its no good will just buy a straight through muffler shouldnt cost much.

D22 King
09-01-2009, 03:18 PM
gave the blokes at hedland diesel and exhaust a call today at they quote me a grand for a custom built 1. 3.5 inch straight thru from the turbo with only a cat

09-01-2009, 03:42 PM
Dont bother with a 3.5 inch system. If you were running a 6BT Cummins (5.9L, 6.7L), Duramax (6.6L V8), Powerstroke 7.3L, 6L V8 then yeah but not for a ZD30. Good luck fitting it under the ute aswell.


10-01-2009, 02:52 AM
the 3 litre are know to sometime hit the exhaust on the chassis at full noise with a 3". i doubt you will get a 3.5" to fit.
not to mention there will be very little increase in performance, it will be nosier and cost a whole lot more.
a lot of the off the shelf systems are 23/4" there is no point going big if you have a restrictive cat in it.

10-01-2009, 12:21 PM
I'd like to see anyone get a 3.5" system under a D22 without it rubbing just because I reckon it is impossible without a body lift. My 3" rubs on the floor when the drive train is under high torque loads and that is with 30mm clear minimum along it's entire length.

10-01-2009, 10:07 PM
My 3" system dont rub anywhere Shonky.

It does vibrate under load at 1800rpm though.

11-01-2009, 12:42 PM
Go a 2.5 inch or a 3 inch.

3.5 inch on a D22 is to big.


11-01-2009, 01:02 PM
My 3" system dont rub anywhere Shonky.

It does vibrate under load at 1800rpm though.

Mine touches if I give it a boot full in first gear, one of these days I'll have to have a good look at the engine mounts, they seem a little on the soft side to me, letting the clutch out with the foot on the brake until it almost stalls sees the top of the engine move over a good 30-40mm.

11-01-2015, 12:33 AM
Im thinking of replacing just the muffler as I reckon its way to big and i cant afford a new system yet . Anyone have any ideas on this thought process or is it just a pipe dream ( get it ....pipe dream...... ok sorry bout that ) ok cheerio .:cheers!:

11-01-2015, 01:21 AM
Im thinking of replacing just the muffler as I reckon its way to big and i cant afford a new system yet . Anyone have any ideas on this thought process or is it just a pipe dream ( get it ....pipe dream...... ok sorry bout that ) ok cheerio .:cheers!:
Allot of people have replaced the muffler and love it. Anything that isn't the stock system will be better.

It cost me $100 for a muffler delete pipe on my 3" system to be made up.
The while system cost me only $500....
Almost half way there when you think about it,....

Save your dollars is my money,you won't regret it!

03-02-2015, 10:21 AM
hey there guys. My warranty is almost up so the mod bug is calling. Not looking at anything crazy just the usual and of course everyone has different ideas on the way it should be done. I'm thinking of an exhaust upgrade as my d40 only has a 2 1/4 inch and thats being generous. How have people gone with their exhaust cause after research I have noticed a few people have gone with a 3inch pipe turbo back with just a high flow cat. Is this correct or am I missing something. Also Mike1303 is yours a d40 or d22? would be interested on hearing yours as I see your in canberra. Also who did you get your exhaust from?

03-02-2015, 10:28 AM
Assuming it's a d40, I have Turbo back "3" exhaust with only high flow cat, all straight pipe. Not loud at all barely notice any difference in cab, has a nice note to it outside but definitely not loud at all.

03-02-2015, 10:43 AM
Hey johnkathy81, yer I did a search and saw your posts about yours. One question I had for you was when did you hear that baffle sound? was it the whole way through the rev range or was it when you backed off and I guess it was real annoying. Maybe like a blow off valve (haha)

03-02-2015, 10:51 AM
Mine is a bolt on fitted myself I originally ordered it with no cat and one muffler now have no muffler and high flow cat. The way I first had it made it sound that way although now with high flow sound is spot on, no drone or anything with straight pipe at all.