3" Exhausts and low RPMs

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G,day gents,

I solely embrace democracy and i fully support healthy debates such as this thread.

As with all information on any subject matter it must be support by solid evidence/facts
or sound theories. Thats what helps us to chose what ever product that we feel is right for our particular need. When i became a part of this thread, i wanted to know which exhaust system was best for my D40 Navara, this has brought Northside and Unichip into the debate which is fantastic for all.

After following this debate over the last week, i then contacted 6 top exhaust specialists for there advise, 3 replied and i have not heard from the other 3. However, please read their comments to my enquiries below.

Regards, RLI

G,day Gents,

I am seeking advice regarding upgrading my standard exhaust system to a either 3inch or 2.75inch mandrel bend system.

I have a Spanish built 2005 Nissan Navara D40, manual 2.5lt diesel turbo dual-cab ute.

I have been seeking advice on various 4x4 websites to which exhaust system to put on my D40. It seems that every one has a different opinion.

So far I have been told:

1. 3.0 inch mandrel bent including dump pipe and high flow muffler is the way to go.

2. 2.75 inch mandrel bent including dump pipe, high flow cat and high flow muffler is the
way to go.

3. Either a 3inch or 2.75inch straight through system is the way to go

4. 2.5 inch including hand made dump pipe and mandrel bent pipe is the way to go.

5. Another person states that you cannot replace the dump pipe because the cat is in there.

I am confused as hell, please help!

It appears that the majority of people advise either a 2.75inch mandrel bend exhaust system or a 3inch which do you recommend and what are your reasons?

I await your reponses.

Kind regards,

RLI

(1.)

Hi There RLI,

Thank you for your enquiry.

We recommend that you have a good quality air filter & snorkel fitted to your vehicle first as this will help bring more air into your engine helping keep it cooler & giving you better performance from your vehicle, then your exhaust & chip fitted.

If you are unable to have the exhaust & chip fitted at the same time we suggest you have the exhaust fitted first as it reduces your exhaust gas temperature where as if you fit the chip first you will find that it will raise your exhaust gas temperature.

It doesn’t matter whether the vehicle is a 2.5L Pathfinder or a 4.5L V8 Land cruiser Ute our Turbo Diesel Exhaust Systems are a 3” Mandrel Bent. The reason we use a 3" system is that it provides us with biggest possible EGT (Exhaust Gas Temperature) drop. We then use an aftermarket Chip/ Module & put the fuel back in, where we then bring it back to the factory EGT’s by doing this we find the best power gains which can lead to better economy.

We also recommend that if you are doing beach work or are in & out of salt water then you go for the stainless steel system as this is more suitable for these environments.

Also please be aware that our systems are not like any other system on the market. The Taipan XP is a far more superior product as it comes with the vortex muffler. The Vortex Muffler system helps provide more power & give better performance than that of the conventional muffler system as it helps draw & push the exhaust gas out giving you a lower EGT. Our systems are also aluminized & where dump pipes are applicable ceramic coated. Our stainless steel systems are manufacture from 304 grade stainless steel.

I understand your confusion please rest assure that all information that I have provided you is correct, we have over 30 years experience in the exhaust industry. If I can be of any further assistance please do not hesitate to contact me.

Kind Regards

Taipan XP 4WD Diesel Performance Exhaust Upgrades - Australian Owned - Performance that Bites


(2.)

Hello RLI, it’s pretty confusing on these forums. I cannot believe a lot of what is said.

1. We only make 2 ¾” dump and system for this vehicle. We can bend from 1 ½” to 5” but have found 2 ¾” is the optimum size

2. We recommend running a cat also. It is hi flow and offers no restriction. The muffler we use is also hi flow. You can roll a golf ball from one end to the other.

3. By Straight through I am assuming you mean no muffler. This option is fine when stop and starting around town but believe me at 100 k an hour you or your partner will want to be climbing out of the truck. Extremely drony and as I said with our muffler no restriction no advantage leaving it out.

4. Our 2 ¾” dump is hand made.

5. The cat isn’t in the dump but is part of the dump and cat pipe.

6. The reason we use 2 ¾” is because 3” will over exhaust and can and does cause boost spike sending the vehicle into limp home mode. A number of manufacturers who use 3” restrict the system back in the muffler.

We make a 2 3/4” mandrel bent system with hi-flow converter and dump pipe to suit your 2.5ltr D40 Factory Turbo Navara. We require the build date and series of the Navara.

These exhaust systems are all bent and built in our own workshop with our automatic mandrel tube benders, by our highly experienced, qualified staff. All kits come with nuts, bolts and gaskets supplied (apart from gasket off the back of the turbo-which is quite alright to use again) and fit on to all original mountings and brackets. We supply a hi-flow, perforated straight through type muffler. This means that the muffler won't restrict the flow of the system due to it being the same size diameter as the tube and the system won't be any louder then standard as the perforations absorb any excessive noise or droning.

Our customers have given us good feedback, being extremely happy with the improved torque and fuel economy of their vehicles after installing one of our systems. We have found that we sell a lot of our product to people towing large vans and boats looking for more power to get them up hills and along passing lanes. On average our systems give customers an approximate power increase of up to 15% and an improvement to fuel economy by approximately 12%.

The price for an aluminised mild steel system is $1185.00 plus $25.00 for packaging, plus freight.
The price for a stainless steel system is $2000.00, plus $25.00 for packaging, plus freight.
Alternatively we can fit it here in our workshop for an extra $300.00.
* Please note fitting costs may vary depending on series of vehicle.

Thanks for your enquiry. I hope to hear from you again soon.

Regards
Noel
(3.)

RLI,

Please call the phone number below and we can discuss..

Best Regards,
Jeremy Mcalpin
Program Manager,
Sterling Performance Exhaust’s & Chips.
Phone: +61 (2) 1300 992 195 Fax: +61 (2) 6578 8690
Sterling 4x4 Performance Exhaust: High Performance Exhaust Systems & Kits SPT
 
Hi all,

I would like to add what I know about playing with vehicles of all descriptions, firstly some background, I am Plant Mechanic (with Mech eng done post trade); I have been in the “diesel” industry for 25 years.
I make my living my living by maintaining, repairing etc heavy plant, from 20t hydraulic excavators, up to twin engine Hitachi EX5500-6 excavators (two 2000hp V16 quad turbo Cummins) along with many other 2000hp + truck, dozers loaders etc I have rebuilt hundreds of V12 and V16 2000 hp + engines, from remove from plant, strip, order parts, rebuild, dyno, install and test, many of these bit of gear worth $6 to 15 million.

I am not an expert, but I have a bit of experience.

After reading this entire thread, along with many others, as I am waiting for my D40 to arrive and wanting to learn and decide on future mods, it appears to me that Both Lindsay from Northside and Robert from Chip-it are “on the money”, I can see that both are telling honest results of tests they have found, saving all of us a lot of pain and money from trying what doesn’t work, or wont make any difference.

Lindsay’s point about the 2.5” being all you need on a 2.5lt engine is correct, he has not said anywhere the 2.5” flows as much as the 3”. He has said the 3” offers no advantage over the 2.5”. If at a later date you were to add a more efficient intake tract (bigger turbo, better intercooler, better pipe work to cooler, head work, improved manifolds, etc etc etc) then the 3”, or maybe even bigger, may be of some advantage, but in its current setup a 2.5” will do all that is required with room to spare it would seem. Saying that, I have not seen any reason not to run a 3” if you want to, other than clearance issues, cost, noise etc.

As for the Engine control modules (chips?) themselves, to compare a unichip and Chip-it are like trying to compare different swim suit models, both do the job, both are very good indeed, but there are trade offs with both,
Complexity of install with the unichip if you decide to go the wire in way, but this then allows you to use the greater range of features available with this unit. This is not an attack on the Unichip unit, this is just the way it is, Plug and Play appears to be available, what features you may loose I am unsure of, but going by the pictures, it doesn’t look like a 5 minute install or removal.

I have installed quite a few Chip-torque xede units in BA/BF turbo falcons and whilst it is not a difficult job, even after doing several, it is a job that will try your patients if you want a stealth install, without removing the ECU, mounting the unit behind the Glove box and keeping the harness looking factory, it can be done, but takes about 4 hours to hook up 9 wires from memory.

The plug and play option of the Chip-it unit would appeal to a fair majority of people, the ability to remove the unit with ease when selling, or maybe a warranty issue would also appeal, this however comes at the disadvantage of not offering as many tuning options as either the unichip or a full ecu upgrade.

Having played with turbo falcons a fair bit over recent years, and trying several different tuning units, it is almost impossible to beat the factory tuning control methods, not until a unit which could rewrite the factory ECU became available was the real potential for the falcon opened up, I doubt we will see this for the Navara any time soon, so a decision has to be made on which way you want to go, cheaper and easier or more complex and higher abilities to tune.

The open way in which both of these guys offer information is nice to see, I have been on other forums where different tuners would bag out, lie and show utter disrespect for both customers and other tuners, to see the open display of respect is a credit to both guys, who are, by the way, making their living from selling their wares, so they have a little on the line, to Play Nice with each other is good to see.

If I was to make a wish list for a tuning unit it would have the following features.

Control over both fuel pressure and injection duration.
Control over injection timing.
Control over boost level and control over the full rev range, so boost can be removed at higher rpm as required

It would also have the ability to reduce boost / fuel pressure / injection duration / retard timing (any of or a combination of any) to control EGT’s and coolant over temps, these two will go hand in hand, but EGT will spike up and down with gear changes and reduced throttle settings, the coolant will be a more stable indicator of high load over longer periods, this would involve the use of EGT probe (before the turbo, no use after) boost sensors after the cooler, and engine coolant temperature sensors before and after the radiator (inlet and outlet of engine).

I would also like the ability to have these temperatures and pressures displayed on dash, either through different gauges or on a small LCD screen. EGT and true coolant temp are the two I want to see the most. Boost is a non essential bit of knowledge really; the other parameters will set the boost, no real need to see it.

From what I can see, the unichip looks like it can do the above; I would be interested to find out if it can. I would also like to know if they would be willing to sell me a “kit” with the appropriate probes and sensors, so I could install and then have the car tuned. I live in regional NSW, work 60 hours per week + 15 hours travel, and don’t have the time or desire to drive to QLD and have my car there for 4 days while it all gets installed and tuned.

For anyone who doubts the importance of keeping your EGT in check, head the warning, you will fail an engine (cyl head) if you run too high temps for too long, we have 2000hp Cat V16's, 4 valve per cyl, electronic injection engines, they last around 16500 hours in a 280 tonne truck specification, they die for two main reasons, too much fuel through a damaged or failed injector causing a high temp on that cylinder, a piston to melt and grab the liner, throwing a conrod or two out the side of the block, or HIGH EGT causing dropped exhaust valves, it sounds like a million little men with hammers wanting to get out, they do, through the turbo's, it isn’t pretty and happens a lot, the cause is HEAT, to much fuel and heat will kill your engine.

Sorry for the long post.
 
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Man this thread has been a great read! As many have stated earlier, thanks to Northside 4x4, Chip It and all others who have added to this thread. The information is exactly what people like me are looking for when trying to decide between products and different mods. I've just upgraded my exhaust (3" dump back) and will be throwing a snorkel on soon so i'm looking forward to IC and chipping next. I am eagerly awaiting any responses to Chris C's comment above... keep up the healthy debate!


By the way Chris C, I've got a few less years of experience than you mining but i've also seen a few D11's and 89's/93's with legs thrown out of bed. Not pretty and makes a nice bang :)
 
Awesome info, thank f@#k. It is a minefield.
Great if you can get answers to questions you ask, even better to get info on questions you didn't know to ask.
 
Been a while since I've posted here. I made a mistake in posting what I had was a 3" straight through, it's a 3" (downpipe included) mandrel bent with a high flow muffler. Apologies I thought they were the same as I haven't seen anyone here running straight pipes as they are said to be too noisy.

Robert, I've since gone to the tuner of my current chip and after some adjustment low end torque improved. Still not the same as when I had just the chip with the standard exhaust though. But on the highway it sings. Methinks the boost on the mid boosted yd25 engines (106KW) come way later in the rev range compared to the high boosted yd25s (128KW).
 
@Northside4x4
As far as I can tell the 126KW and 106KW versions sold here (Philippines) are the same but the ECU tuning is different. Everything from the turbo to the IC piping are the same. Yup max boost on the 126 is 25psi? on the 106 around 19psi. Maybe different in Australia.
 
The turbo is different. Same GT2056V designation, but different part nr. 126KW is oil and water fed. 106KW is just oil cooled.
 
...
The cheat solution to the lag is to simply overfuel the hell out of the engine to light the turbo up quicker ... .

I disagree.

Add more fuel "YES" ... overfuel to hell. A definite NO.

You do NOT need to overfuel to hell. Those that have a our Chip on the D22 will know you don't need to do this to get great results.
 
If I was to make a wish list for a tuning unit it would have the following features.

Control over both fuel pressure and injection duration.
Control over injection timing.
Control over boost level and control over the full rev range, so boost can be removed at higher rpm as required

It would also have the ability to reduce boost / fuel pressure / injection duration / retard timing (any of or a combination of any) to control EGT’s and coolant over temps, these two will go hand in hand, but EGT will spike up and down with gear changes and reduced throttle settings, the coolant will be a more stable indicator of high load over longer periods, this would involve the use of EGT probe (before the turbo, no use after) boost sensors after the cooler, and engine coolant temperature sensors before and after the radiator (inlet and outlet of engine).

I would also like the ability to have these temperatures and pressures displayed on dash, either through different gauges or on a small LCD screen. EGT and true coolant temp are the two I want to see the most. Boost is a non essential bit of knowledge really; the other parameters will set the boost, no real need to see it.

Working on it. 3 months I reckon. The unit will have ALL the bells and whistles. Built by us, right here in Oz. With LCD display of tune state, EGTs warnings and screen selectable tunes.

and this is a scoop for the Navara Forum ... it will be well suited to experienced tuners, as we will be able to control the following:

Injection timing via crank angle, injection duration, fuel pressure, boost pressure.

The ECU will also have the ability to run an alternate injector and fuel pump etc for the likes of Petrol or Methanol Injection (on diesel), or LPG. The ECU will also be able to Tune Petrol Vehicles also if you like, controlling timing & AFR via MAF intercept and be able to breakdown & select the window you really want to target over 21 points, ie 4000mv + on the MAF when in Open Loop 4000mv-5000mv + over a RPM table etc to give control of AFR's and of course timing via crank angle signal intercept.

You will be able to use it to run a extra injector etc for High Performance vehicles / rice burners etc :rock: as required, with 12 tune levels able to be selected via in cabin touch colour screen. The system will also have progressive & programmable EGT control It will send a cat amongst the pigeons even further lol. :cheers!:

Will also have 5 years warranty to boot.

Price.... circa $1700.00

It wont suit everyone but ... it will suit those that want EVERYTHING.

This is from just a little ol' Aussie company that just go about things quietly. :)
 
Robert that sounds pretty damned cool.. And I'm very interested as I am in the market and have been looking at Steinbauer, DP Chip, and Tunit..

Anyone in TAS that might have the nous and know how to install and work one of these things though?

I'm not all that convinced there is.. Or I'm travelling the NSW South Coast and Vic over Xmas / New Year. Could always drop into someone there maybe.

Cheers

T
 
Correct. Howell have been tuning cars for a long time. They have a great legacy from a respected tuner.

They also stand behind their work which is bloody important.

I will give you an example. They had a customer with one of our chips (on a Hilux if I remember correctly) not able to start the vehicle. Shane got the message very early one morning (a long time before the start of the work day) and went out on site to get the guy out of trouble. Customer was on his way after he noticed our harness had a fault on the terminals of the CR plug. I dont know many that would do this.

Thats how you get a good name in the industry ... Howell certainly have that.

Two thumbs up ... well done guys
 
Amazing the 3" System actually does start with a lower EGT, and finishes with a higher EGT. Over the course of that run, the EGT would have averaged out maybe 2-3deg in favour of the 2.5" system.

3" System is definitely more profitable for me to sell, and would require far less explanation and proving of my methods to possible customers. But thats how I am, I do things right. I dont just do them the same as the next guy.
Ok so I'm a little confused by all of this.. I am looking at getting my D22 chipped with a Chip It (yes sorry I know this is a D40 thread) and a 3" exhaust was recommended. So is it better to have a 2.5" or 3.0" or it doesn't matter squat from these graphs?
 

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