Improving the TD27t

[fh2014]

Hi all,

Have been busy working on my terrano since I bought it as a hack/something to tinker with and am happy with how its been performing, however I feel its underpowered especially since the new wheels and tyres went on. Basically I wanted to go over everything possible in order to improve this motor. Yes I have done plenty of searching and yes I have an auberins EGT gauge on the way. boost gauge is in and reads 8psi max (2psi shy of the factory setting I believe, hopefully figure this out when I get stuck in).

In no particular order (someone can rearrange this order perhaps?)

-block EGR and remove all associated pipework/butterflies
-intercool
-service engine oils, air filter, diesel filter etc
-full exhaust system, looking for input on pipe size here and mufflers
-clean out intake manifold
-catch can
-increase boost , looking at 18psi here , sibainmud seems to have had success in this dept.?
-increase diesel delivery 1/4 of full load screw?

Let me know if I have missed anything. I have already intercooled with an isuzu bighorn 3.1D cooler, duct and scoop complete with a 7" fan sucking from underneath switched from cabin. Would be nice if I could switch it from the speedometer to auto switch off at 30km/h or something like that but don't see it happening

Here she is in stock form



and here she is today.

[johnny262]

Good lookin wagon mate

Valve clearances, recon injectors, maybe advance pump timing..?
If its auto search for torque converter lock up mod or google DIY shift kit

[stovanovich]

I have done most of the things on your list (except I have however installed performance free flow muffler only no full exhaust yet & boost 15psi) they definitely make a difference in spinning my 32s. I also installed a water sprayer over the intercooler to help cool instead of a fan. You definitely notice it working to keep the EGTs down coming up the Bombay's just a little squirt every so often when you see the temps getting up around 500 brings it back down nicely again. So heaps of headroom to heat up.

[sibainmud]

Best ya phone or text me
021 742228
Cheers

[fh2014]

She's manual. 200kms. After driving my mates manual navara td27 non-turbo and it feeling like it had the same power as my motor (minus the sliiiight power increase I feel from the turbo coming on) I'm really starting to wonder.

Tried removing exhaust from dump pipe back and intake at s-bend last night to see if there was a flow issue. No noticeable improvement, just really fkn loud. Then popped off waste gate actuator line and plugged intake side. A small improvement ...however it struggled to get to 14psi and eventually popped open that safety overboost valve. Would only get 14 after a long hill in 3rd at about 3200rpm. Will try remove inter cooler tonight and just run factory pipe to rule out blocked or leaky cooler.

Maybe the turbos tired? Am I asking to much of a 22yo diesel 4-banger?

Getting plates made up to block EGR later this week.

P.s. Water-sprayers a nice touch stovanovich, did you just use the headlight wash or rear window wash pump? Sigh, will add it to the very long to do list

[Crash bandicoot]

yeah some thing not right there, mine hits 14 psi just going from 50 to a 100 leaving town.

On the 42nd traverse trip i following a mates ST-X navara, i had the boost at 18-19 psi and could keep right up behind it on the mangaweka deviation and the big steep passing lane just before the napier /taihape road intersection

although my TD27 is a 98 vintage with factory intercooler it has the earlier mechanical pump. it will easily keep climbing up the speedo even on a moderate incline.

[Broughto91]

so what would cause it not to boost properly? mine struggles to get to 12psi and is near on 4000rpm when it gets there

[tweake]

so what would cause it not to boost properly? mine struggles to get to 12psi and is near on 4000rpm when it gets there

lots of things.
waste gate setting, wastegate leaking, cracked turbo housing.
manifold leaks, egr stuck open, egr pipe cracked.
air intake restriction
not enough fuel.
broken vanes on turbo

[Crash bandicoot]

potential issues are

actuator atop the injector pump not working correctly
actuator full of crud over the years pushed in from the hose from the turbo housing.
actuator's diaphram is perished
hose to actuator is perished closed up from age.
plunger not opening fully.

potential turbo issues

exhaust or impeller wheel on turbo damaged or worn away, or turbo bearings are not free spinning.
wastegate not closing properly or damaaged worn and not sealing.
waste gate spring lost tension allowing creep (takes ages to hit full boost)

fuel delivery is the key to making boost...you can feed all the air you like into a diesel but without fuel you will still only get 12-14 psi at the manifold.
I'd be looking at freshening up the fuel delivery before the turbo charger...14 psi is hardly stressing a a factory fitted turbo...ya need to get to around 20-25 psi before the turbo's shit them selves.

one question i do have for you.....hows the injector pump timing? do you find it never gets warm unless its an absoulte gut slog of a hill or find its gets warm quite easily? .... mine operates between 1/4 and 1/2 even in a mud hole with the radiator full of crap

[Broughto91]

Thats alot of helpful info cheers for that

While 4wdn it doesnt normally go over 60c and normal open road it sits between 80-60 depending on outside temp, towing and head wind it sits 90+

[MUDFINDER]

What bonnet scoop is that you're running? looks good!

[stovanovich]

Appears to be one of an Isuzu Bighorn I would imagine

[fh2014]

Have turbo off motor now and no play in shaft, spins smooth. Does anyone think its worth getting the oil seals pressure tested? Or is there a seal kit/recon kit for these things? Or even somewhere I could just take it and they give it some love? North shore AKL

Think the problem is fuel delivery = not giving me the boost. Would rather rectify the problem before turning up the fuel screw. But turning up the fuel temporarily will prove the theory? Time to start learning myself up on the diesel fuel delivery system

Intake and exhaust manifold are off. Intakes getting cleaned of EGR gunk, EGR pipe removed and blocked off, safety overboost valve removed and capped. Exhaust manifold getting EGR blocked off and EGT gauge probe threaded in.

Next problem;

Quite a bit of oil in the intake. (again - Turbo seals or crank breather) Will have a catch can of some sort fitted when its back together. This is another story all together. People seem to be fitting these things and blowing seals due to not paying attention to the required pressures of the crank breathers. Or complaining that the can doesn't catch oil/fitting steel wool inside etc. It got me thinking that there must be something better for diesels because we have a much larger crankcase blowby than petrols - a catch can is not the answer. Catch cans are for ricer petrols.

Found a document on Cummins diesels crankcase breathers and they have put some serious thought into the breather. (Size warning) https://www.cumminsfiltration.com/pdfs/product_lit/americas_brochures/LT32599_06.pdf

Maybe I'm going overboard and these are only required on massive trucks etc but,

We need something like this http://www.ebay.com.au/itm/PRO-VENT-200-CRANKCASE-BREATHER-PROVENT-4WD-/261014128326?pt=AU_Car_Parts_Accessories&hash=item3cc5a786c6&_uhb=1

Thoughts? Looks much more fit for purpose and are they sold in NZ?

[sibainmud]

OTT bro, it's a TD27! The reason for the dump can is to catch as much of the oil haze as possible. Also when you turn up the boost the extra induction can suck the crank fumes through the catch can. I have dumped mine on the chassis rail and not much came out. Most of the oil in the crossover and S bend will be from the breather. Clean it all and put back together. You won't achieve the real boost until the fuel is wound up (provided the engine can breathe and fart properly!). Thermal expansion is what drives the turbo. Here's the best money I ever spent,


Cheers,

[lax2wlg]

The only thing I dont like about the td27 is the lack of low down torque, which is essential for an offroad vehicle. I would like max torque by 1500rpm.

I suppose low ratio transfer gears would help in this respect. Maybe there is some turbo option that would help. Crash or slide or tweake would probably know more about this.

[tweake]

The only thing I dont like about the td27 is the lack of low down torque, which is essential for an offroad vehicle. I would like max torque by 1500rpm.

I suppose low ratio transfer gears would help in this respect. Maybe there is some turbo option that would help. Crash or slide or tweake would probably know more about this.

variable turbo would help
but for offroad nothing beats low gearing.

[Crash bandicoot]

The only thing I dont like about the td27 is the lack of low down torque, which is essential for an offroad vehicle. I would like max torque by 1500rpm.

I suppose low ratio transfer gears would help in this respect. Maybe there is some turbo option that would help. Crash or slide or tweake would probably know more about this.

Why ive gone for the qd32 block n head, with the pump ive already modded and the factory turbo at its safe limit.(around 18 psi) ive been harrassing bmw's and folden falcodores on the highways.

[fh2014]

thanks for the input i do go a bit ott i like try to do things once and do them properly.

would very much like one of those downpipes and a full exhaust system. horrible down pipe on that turbo. who made yours/where can i buy? im hopeless with a welder unfortunately. only good with wires (electrician)

found one problem, my own doing, was disconnecting and plugging off the boost compensator line. was told it was part of the EGR and to plug it when putting intercooler on. seems like its vital to increasing fuel delivery as boost increases according to page 38 of this bosch VE diesel pump manual. Manual Download



Pretty sure thats the right pump or similar.

[fh2014]

potential issues are
.......

one question i do have for you.....hows the injector pump timing? do you find it never gets warm unless its an absoulte gut slog of a hill or find its gets warm quite easily? .... mine operates between 1/4 and 1/2 even in a mud hole with the radiator full of crap

its always running very cool, maybe 1/8 to 1/4 on gauge. only gets to halfway on a very big hill (think top of bombays). is this normal for this motor?

[tweake]

............ seems like its vital to increasing fuel delivery as boost increases........

correct. you need the boost comp working.
tho technically it doesn't increase the fuel, it limits it at low boost.

[fh2014]

Has 4.8 diffs, highest for off-road but screams at 100ks.

EGR removed and blanked.
Spent hours clearing intake manifold and ports with a scrape tool and brake clean .
Overboost valve removed and blocked.
EGT gauge in.

It's like a new truck
Will now plod along and up hills in 5th half throttle. Whereas before it was 4th gear foot flat.
That intake must have lost about 20% of the port size I recon.

Loaded it up with weight and took it up some massive hills highest I got it was 688 deg C
Then again with inter cooler + fan highest I could get was 639 deg C

Next is boost, pump timing and fuel flow.

[fullthrottle]

Let it breath.
The most significant difference to mine was making a 3 inch expansion chamber from the turbo, that reduces down to a 2.5inch straight through exhaust. The intake also needs a little help and so open it up a little. The standard airbox isn't really good enough.
If you're thinking of doing a snorkel, make it large and not black. The heat inside there on a hot day raises the air temp considerably. When I say black, well you could probably use that new black paint from Resene that is actually cooler than light colours. Some special thing they have now.

So anyway, my turbo spools much faster and engine revs much quicker with this in place. It will finally do burnouts with MTs and a tightened LSD now

[crosdptd27]

how much difference does the new dump pipe make??

just on the difference turning the fuel and boost up - its like a whole nother ute! running on 1bar and had to turn that pressure up ALOT to get to 1bar but still only sits on 650d up the bombays 100km in 5th or around 350d crusing at 100!

[Crash bandicoot]

You can put as much fuel in as you like. Aslong as the boost goes up to match and keep the ratio right it wont get hot.

[fh2014]

Didn't realize these things could get up and boogie

Diesels up, timing good, boost is at 18psi. It tears up anything I can throw at it now. chomping at the bit to get an dump pipe/exhaust made up now - that would be the icing on the cake for this TD27. I guess if anyone was still unhappy here you'd need to go manifolds and bigger turbos. but I'm happy.

Some black smoke off boost but suspect that could be sorted out maybe tweaking fuel a bit more. I got it seriously stuck and managed to see 721 deg C peak. still 350 at 100 on road and 700 up long hills. Could be going too high with the temps.

[Crash bandicoot]

How did you find the Idle after adjusting the fuel limit screw?
Mines running 18 with a little black smoke but 700 isn't too bad, ive heard of engines peaking at 900-1000 on long hills. taihape deviation for one.

[fh2014]

Idles about 820-850 warm. Tried to move the lower limit/idle screw after, but it wouldn't budge and it just looked like I was going to snap it off. Oh well, the higher idle doesn't bother me much.

Good to know about the temps. Just guessing here but exhaust might help get that temp down some more. It runs a little cooler with just dump pipe.