3" Exhausts and low RPMs

good on you northside 4x4 for all the test at least we can see what going on

mate do you think you can do a test on a DPF race pipe (from chipit) to see if it is worth getting an if they do work

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Yeah I did read the whole topic mate.

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So, 2.5" or 3". I'm bloody confused. Which is better for towing?

My old man has a 3" on his Pootrol and it sounds like tractor.

northside 4x4

I,m looking for better fuel economy(like all D40 auto) and for towing i tow a caravan 1700KG and it's 3m hight

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Isn't the stock pipe 2.25" though? 0.25" seems to be a small difference unless it doesn't have a cat. How do the EGTs on a 2.5" compare to a 3"?

Yes but the stock exhaust isn't mandrel bent so has lots of restriction in the bends.

I recently put a 3" dump on mine, and i seem to have a bit more snap off the line and definatly pulls harder through the the rev range, I,m happy with the improvement it made and the fuel saving is also noticeable, and with also doing the EGR blank a while ago, i have also cut down the amount of soot that used to come out of the exhaust,, So far i,m happy

G,day Gents,

I am new to this forum. I have a manual Navara D40 2.5 turbo diesel.

Iam seeking advice on which exhaust system best suits the D40 3inch or 2.75inch?

I have recently purchased an off-road camper trailer and my family and i are heading up to cape york in June 2011.

I have nearly finished all the mods on my truck ie, bull bar, side steps, canopy, roof rack,
old man emu 2inch lift, arb rear bar with cutomised spare wheel carrier, uhf radio, compressor, rear diff lock, dual batteries, dba front rotors, direct clutch relpacement, ipf driving lights, arb fridge & fridge slide, shovel & axe holder, high lift jack & pick holder, 60 lt under floor water tank, tjm full lengh bash plates, warn winch, diff breather kits and 265 x 70 16 pireli scorpion tyres.

I live in the Coffs Harbour area so my mates and i have an aray of tracks to play with. My family and i regulary travel both to Morton and Frazer Islands. However, we did this in my last 4.2 turbo GU Patrol which i sold 5 years ago due to ill heath. Now we have a dual cab iam starting all over again with the fit-out and the mods which i have to say has been good theraphy.

Based on the information suppied above i am enquiring which exhaust system works best suited to the D40. The 3inch or 2.75inch. Another piece of info to help with your opinions is that iam also looking at fitting a Diesel Power module to the nav.

Regards,

RLI

Northside 4x4 said:

As promised, 2.5" System vs 3" System on a D40. Power and torque graphs.
I will have to search through the dyno a bit more for our EGT test vehicle, as I never bothered doing it on this vehicle after seeing near Zero difference in power and torque.

Click to expand...

sorry havn't had a good read through yet. just wondering which is what on the graph as there seams to be a mix up in colors.

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Northside 4x4, I know this is also off topic but I have a tuning question and this thread has already gone to the dogs.

Have you worked on the Navistar 7.3L turbo diesel circa 2003 in a F250?

What makes such a big diesel engine feel so sluggish? Apparently chipping them makes them really wake up, what is commonly changed in the tuning? And am I right in thinking the auto short shifts out of first into second and if it didn't do this it would be much more "enjoyable" to drive?

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G,day gents,

Thanks for your prompt reply.

Question: If i go either 2.5 or 2.75inch exhaust for my D40. Can i legally run a straight through system ie; dump pipe, cat and exhaust pipe without mufler?

Question: Which exhaust system is better, a mandrel bend dump pipe attached to a straight line pipe system without any bends v the current D40 mandrel bend systems?

The reason why i ask this is, the current exhaust system bends from left to right at the front of the fuel tank (on the passengers side) then bends back at the drivers side, out to the rear of the vehicle. I am thinking of moving the fuel tank and then run my new exhaust system on the passengers side. Would this set-up be better than the current D40 set-up?

I have already moved my spare wheel from under the D40 and have made a spare wheel carrier modifaction to my ARB rear bar where the spare wheel now resides. So modifying the fuel tank to a new location is not a problem.

Regards,

RLI

also does anyone know the laws for running the exaust pipe out the side of the car like behind the back passenger side door?

edit:
its ok i looked up the laws on the vicroads website, now to decide wat to do

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Northside 4x4 said:

Ive not tuned a 7.3 in the same way I have tuned navara's/bt50's etc.. with full access to the ecu.
But basically what makes a nice motor sluggish is weight for a start, and tuning that is designed to get 50000000000000000km's out of the motor while towing a town behind them.

The airflow characteristics of the motor arent great for a start.
The general improvements I do for customers with these vehicles is a full exhaust system, Upgraded turbine wheel, intake system and tuning (gearbox and engine)

All parts I use for most american trucks are Banks, most of the other products are absolute P.O.S's
so Banks exhaust, Banks Comp Wheel, 6 Gun Tuner, Trans commander etc...
It really does perk them up while keeping them safe if you do air flow improvements and chipping.

Click to expand...

Thanks mate. Asking on behalf of the old man. He's up your way, I'll send him to you if he decides to throw some money about.

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