TD42 turbo question

[Cuppa]

At what revs on a stock Td42i motor does the turbo 'kick in'?
I have the feeling that not a lot happens until around 2800 - 3000rpm or even a bit higher which seems a bit high up the rev range to me. I cruise along at 95 or 100kph most of the time & find I have my foot heavier on the go pedal in 5th than when in 4th. I would have thought that 5th should give better economy, but it won't if I'm having to use more accelerator. Balanced against this is my belief that lower revs equates to improved engine longevity ...... So I find myself in a quandary ....fuel economy or a longer life for the motor. (4th or 5th at 100kph)

I know that the weight of the vehicle will have an influence when 'getting up to speed' but I am referring to maintaining speed (with best economy) which is what I thought the 5th gear should be for, but it seems this will only be the case if I increase my cruising speed, which is self defeating as far as fuel economy goes.

I suppose the reason folks fit bigger bore exhausts is to allow the turbo to kick in at lower revs? Does this allow better fuel economy if the temptation to accelerate & cruise faster is avoided?

Cuppa

[nissannewby]

The best thing you could do budget wise, economy wise and boost wise would be to fit a 3" exhaust and dump pipe and get it tuned you will be amazed at the difference. Being in Vic diesel tech would be who I would go and see but I'm unsure of the where abouts in relation to you. They are in lily dale I believe.

[nissannewby]

The dullness of these factory motors has more to do with the fuel pump setting than boost. To get boost you need fuel and as your feeling your not really getting enough fuel until its basically too late and that's when your feelin the boost. Getting a tune they alter when the fuel starts delivery and this makes a huge difference to response and what not.

[Cuppa]

Trouble is as soon as you get a 3" exhaust & dump pipe, someone says "you need" a pyro gauge/better intercooler/bigger bonnet scoop etc etc. I have the sense that any move away from stock sets you on a path of always needing more. I'm not that keen on developing a pyro gauge paranoia/obsession when driving (which seems common amongst those who have moved away from stock equipment & settings) ..... So if I did end up just fitting a 3" exhaust & dump pipe plus a fuel pump tune could I safely just leave it at that...... Or would I need other stuff to be 'safe' bearing in mind it's economy rather than rorty performance that I'm interested in.

Cuppa

[Ben-e-boy]

If it is economy you are after than nissannewby is right. you will see better economy with those mods. In my ute I have a hevily modified pump pumping in alot of fuel.
With the 31's on 4 inch lift on my last trip to brisbane I averaged 11L/100 hwy and city driving and at times I was not light on the throttle especially up some of the hills on the hwy

it gives bigrig the s@&ts I think. My ute has more power and better fuel economy than tank lmao

[nissannewby]

A mild tune by a professional and you could get away with not needing a pyro but in saying that once you have a 3" system and tune keeping an eye on a gauge is easily done when the outcome is so good

[Cuppa]

What sort of money would I expect to pay for 3" system plus a 'mild tune'? How much extra for a pyro (egt?) gauge fitted. Ballpark figures?

[macca86]

I thing egt is about 300. 3 inch system 900 to 1300 pending on what you get not sure on tuning

[nissannewby]

That are so common these days a 3" exhaust fitted shouldnt be any more than $1000 and I would expect to pay up to $350 for a good tune. Pyro's arent cheap so prob around 300 fitted for one of these.

[Cuppa]

Thanks all, the info has certainly given me food for thought. It's all money, but improved driveability and new rear suspension are both things I think I'll have to bite the bullet on sooner or later.

Cuppa

[PMC]

G,evening Cuppa!

The following is a cut and past from my build thread regarding an 3inch exhaust! I hope this info might be of assistance to you!

Regards,

RLI


"Well I have just fitted the easiest exhaust system in years!

I have fitted over 7 systems to my Patrols and Navara’s over the last 10 years. These include 2 x Beaudesert systems, 2 x Taipan and two custom made jobs. The Scott’s Rods 3 inch 4.2 TD GU Patrol Wagon one has been the easiest to install.

I was impressed with how quick it all fitted up and all for $590.00 delivered. Wait there’s more, they even sent me a $25.00 discount docket to be given to a friend to use, they even sent a solid pen and key-ring.

http://i1067.photobucket.com/albums/u434/RLI1/IMG_1346.jpg

http://i1067.photobucket.com/albums/u434/RLI1/IMG_1347.jpg

It is easy to see why the factory system is so restrictive!

http://i1067.photobucket.com/albums/u434/RLI1/IMG_1349.jpg

http://i1067.photobucket.com/albums/u434/RLI1/IMG_1350.jpg

http://i1067.photobucket.com/albums/u434/RLI1/IMG_1351.jpg

I fitted the new 3inch exhaust yesterday, what a difference that has made to the GU folks.

[I]I also fitted up my boost gauge and took the beastie for a decent run around! Traveling at 100ks by the GPS and in fifth gear at 2000 RPM the factory boost reading was at 5 psi. Under-load and traveling at 100ks and in fifth gear at i was doing 2300 RPM and the boost reading was at 9 psi. It would be fair to say folks, that the factory boost is around 8 to 10 psi"?

[PMC]

G'evening Cuppa,

I forgot to mention that both Ben e boy and newby are spot on with the advice they have provided to you!

The only reason i am into gauges is, that in my day in the 1980's all the hot-rod boys needed all the info we could get for the dreaded 1/4 mile drags. You can get by with-out having any gauges. However, if you are towing heavy loads, like i do, then it is a good idea to monitor temps, ie exhaust and water and turbo boost.

Classic scenario for monitoring temps. When i was up at Cape York 18 months ago towing a Jayco Off-road camper trailer fully loaded. My tow vehicle at the time was a D40 dual cab and i had over 700kg in the back (i was the recovery vehicle and mechanic, carrying ever farkers spares and tools)

Just before Cairns, i had to over-take a B-Double climbing up a hill. I was travelling around 120ks at 19psi boost, exhaust temp rose to over 750 degrees (I had my pyro in the exhaust manifold for a more accurate reading) and my water temp rose from 170 to 200 degrees in about 5 secs. By slightly taking my foot of the throttle and reducing my speed to from 120 to 110ks, the exhaust temps dropped from 750 to 550 degrees. The water temp went from 200 to 185 degrees and boost from 19 to 12psi.

As we all know excessive heat is the biggest killer of turbo motors! By being able to monitor temps you could possible save yourself thousands in repair bills. Its all about prevention!(if you are able to detect any anomaly's (irregularity, ie egts and water temps climbing dramatically ) you can counter them by talking appropriate steps (reducing speed = reducing heat in the motor in which = helps the motors longevity )

Regards,

RLI

[Cuppa]

Thanks RLI, seems that their prices have risen significantly since you got yours earlier this month, but still cheaper than most

http://cgi.ebay.com.au/ws/eBayISAPI.dll?ViewItem&item=120578103969&fromMakeTrack=true&ssPageName=VIP:watchlink:top:en#ht_774wt_1111

As far as gauges go - I have been convinced of the wisdom of fitting them if getting the exhaust & pump tune done.

Cuppa

[Rip'n'Shred]

That eBay listing includes the dump pipe.
RLI's doesn't appear to include dump pipe.

I fitted a Scotts Rods exhaust a few years ago to my last patrol. Very easy and made a big difference.

[Cuppa]

Ah I see. Fair enough.

Another question: I note that in RLI's pic, on the old exhaust, the flexible section looks much cleaner than on mine. Mine is obviously leaking as it is black & sooty on both the outside of the metal braiding & around it. Would I be right to assume this won't be doing any damage??? (If anything giving a bit of extra flow). :)

Cuppa

[PMC]

That eBay listing includes the dump pipe.
RLI's doesn't appear to include dump pipe.

I fitted a Scotts Rods exhaust a few years ago to my last patrol. Very easy and made a big difference.

G'evening Rip'n'Shred,

You are correct mate! I did purchase mine without the dump pipe!

PS, sorry about that Cuppa!

Regards,

RLI

[PMC]

Ah I see. Fair enough.

Another question: I note that in RLI's pic, on the old exhaust, the flexible section looks much cleaner than on mine. Mine is obviously leaking as it is black & sooty on both the outside of the metal braiding & around it. Would I be right to assume this won't be doing any damage??? (If anything giving a bit of extra flow). :)

Cuppa

G'evening Cuppa,

How many K's have you done mate? When i replaced my old factory unit, i had 250,000ks on the clock! If you have a lot of black soot around the whole flexible joint, then yes you are losing some pressure flow!

I noticed a significant change between the factory exhaust and the new 3inch system and that's without a new 3 inch dump-pipe.

I am currently waiting for my new turbo to be built and it comes with a new 3 inch dump-pipe to suite and that's why i did not purchase a system with a dump pipe. At present i have got a stock standard GU TD42 with an 3 inch exhaust system and i can tell the difference with-out a 3 inch dump-pipe. The dump pipe makes it even breath far better. Creating better low down torque, low exhaust temps and slightly better fuel economy!

PS, i hope this helps shed some light for you!

Regards,

RLI

[nissannewby]

Ah I see. Fair enough.

Another question: I note that in RLI's pic, on the old exhaust, the flexible section looks much cleaner than on mine. Mine is obviously leaking as it is black & sooty on both the outside of the metal braiding & around it. Would I be right to assume this won't be doing any damage??? (If anything giving a bit of extra flow). :)

Cuppa

No damage mate, possibly a tad noisier and as you have stated the mess from the soot but turbo diesels exhaust system need to be as free flowing as possible. A 3" exhaust with dump pipe and a nice little tweak will see you over the moon with the pod launcher

[Rip'n'Shred]

I bought my troll with a 3" exhaust with standard dump pipe and have since added a 3" cast dump pipe. The exhaust makes a big difference and then the dump pipe helps again with quicker spool up and lower EGT's I believe.

More info in my build thread if your interested.