.. 80 Series Diesels What I've Learned thus far .. (1 Viewer)

Joined
Sep 14, 2020
Messages
189
Location
New Mexico
First off I must say that I am still learning and don't claim to be the ultimate authority or expert .. I am a mechanical engineer by trade but my area of engineering epertice was centered in the data center industry .. I have escaped commiefornia and am now located in New Mexico and plan to catch up on all the hunting and fishing I have been missing out on ..

On a comedic note California Gov Newsom the Gov who bankrupted the state has announced that all fossil fuel vehicles will be banned by 2035 .. With the increase of rolling blackout in the state, by 2035 there will be no power for electric vehicles .. I see the genius in this man ..

Now all comedy set aside ..

--

Why are Landcruiser Diesels Sought After by Landcruiser Enthusiasts ? ..

Diesel Engines are typically 10%-15% more efficient than Petrol Engines .. (Typically these are turbo’ed engines with 8-12 lbs of boost) .. Some of the much older very long stroke diesels were also efficient but they did not have turbos and ran at much lower rpm’s with much higher torque .. Wheel twisting power torque is king .. These older 1HD-T & 1HD-FT diesel engines don’t have EGR / Exhaust Gas Recirculation or DOC / Diesel Oxygen Catalyst and so the engines run cleaner and don’t have as much soot running into and out of their engines .. More soot = reduced life ..


What makes Diesel Engines attractive for Industrial use and Enthusiasts alike ? ..

Engine Stroke in high compression engines is typically longer & because of a longer burn cycle than that of a petrol engine. Additionally, Diesel engines can make up to 40% more torque than petrol engines which translates to more wheel twisting power at lower Rpm. Consequently, lower Rpm translates to less friction and lower operating temperatures in non-turbocharged engines .. For this to also be true with turbocharged engines, Intercoolers must deployed in higher turbo boost engines to decrease the Intake Temperatures caused by Turbocharging .. As Turbo pressures increase larger Intercoolers must be deployed to bring down air intake temperatures to operational levels .. By cooling the charge of air entering cylinders more oxygen & fuel can be mixed / burned per cycle increasing overall engine hp & torque .. Diesels can also be run leaner with higher efficiencies at higher boost levels but an decrease of inlet temperatures must be maintained .. Running leaner also means running cleaner but the down side is you can’t allow the inlet temperature be controlled by the ambient air .. I will address this later ..


What is the one thing you can do for Diesel that will increase engine life while increasing intervals between oil changes ?

I recently purchased a 1995 80 Series Landcruiser 24v strait 6 diesel vehicle .. The typical engine life of my cruiser is said to be on the order of 1 million km / 600k miles .. The oil change intervals are 4-5 km .. With an additional bypass oil filter which filters to 2 microns will increase engine life 25%-30% with the stock turbo setup .. An additional 25% increased life for a simple bypass filter we can see this is one of the best investments for a Diesel Engine as diesel engines combustion cycles produce more soot / carbon which enters the engine oil .. Carbon turns the engine oil black and is abrasive .. The increased friction from dirty oil increase surface wear .. Toyota could learn a thing or two about enlarging oil filters to filter down to 1-2 microns which would increase oil life by 3-4 times .. This translates to less frequent oil changes of ~16km / 10k miles between oil changes .. Would larger oil filters be worth it ? .. Yes, the savings in oil costs alone will easily pay off a 3x increase in very large oil filters and more importantly increase engine life .. This by far has the highest payoff of any other modification you do for your diesel engine or vehicle ..


Fuel availability ? ..

This is the current weak area when it comes to diesel engines .. To be fair, there is no path for bio-petrol .. That being said bio-diesel is a good hedge against fuel shortages .. There is a cash outlay for the chemical / tanks / pumps and bits to connect everything but the upside of not having fuel in a crisis makes bio-diesel very attractive .. Will a crisis like this happen in our lifetime ? .. It happened in the 1970’s in America .. When I was a teen I remember the gas lines and the days you could get a fill up .. So never say never ..


Transmissions why automatics over manual ? ..

Automatics really do better in rough terrain than manual transmissions .. This is pretty much the bottom line .. You will have some argument from some but by enlarge automatics take the human error out of the loop .. The down side to automatics is that most of them are adapted from Petrol engines which had much lower torque .. This was the major reason why Toyota didn’t have high boost on the earlier models .. The torque converters were not set up to run at higher torque levels and transmission temperatures suffered due to this, so much so Toyota added transmission fluid temp warning lights ! .. Surprisingly there are ways to fix this issue with diesel up to about 15-20 lbs of boost that doesn’t require a transmission fluid radiator .. A better valve body and torque converter are the two main fixes which have been produced and are upgrades you can get today .. Similarly there is a lockup kit for the higher gears to lock the automatic transmission higher gears to the engine .. This increases fuel economy and decrease tranny fluid temps in the high gears where elevated temps are common due to slippage .. This also increases transmission life which would help to match the engine life to the transmission life .. This in my humble opinion is worth the money as they say a pinch of prevention is worth a pound of cure .. It is also important to mention that transmission lock up devices allow you to use your engine as a brake .. This doesn’t increase the temperature of the transmission fluid .. I must also mention that 3r / 4th gear clutch wear is a real issue in the HDJ80 / 81 Landcruisers more so in the 81’s because of the A343F transmission is weaker in this area ..


Are there increased costs for servicing a diesel vehicle ? ..

Other than the oil issue which we have solved above .. No .. The costs of servicing are less than a petrol engine .. We don’t have sparkplugs to worry about .. The fact that the HDJ81 Diesel cruiser doesn’t have all the additional wiring a petrol engine has should see decreased costs for overall servicing .. There is one downside which makes no sense to me at all .. Why did Toyota using a timing belt when they pioneered belted chains and had used timing chains in petrol engines since the early 80’s ? .. This is probably one of the biggest design shortcomings Toyota has ever done .. At 100 km / 60k mile intervals this timing belt interval is one of the worst of the industry .. I had 1970’s vehicle with a timing belt and it was fairly large .. It was in fact about 30% larger than what is currently on my 1HD-FT motor and the engine was smaller (283 ci) .. This is why I have looked and I can’t find an aftermarket timing chain substitute for this engine .. The timing belt is the weakest design point of this engine .. You will notice that later Diesel engines by Toyota switched over to chains .. I am going to find a chain substitute for the timing belt which should more than double the change interval of the timing chain .. I would bet this would be a very popular upgrade that would make a very large number of us very happy .. I believe that chains of the right length already exist .. All that would need to be produced is the timing gears which shouldn’t be that hard to fabricate .. An existing chain would mean large numbers in production so low relative cost as opposed to a belt .. Chains by in large are more reliable .. Chains do make more noise hence this was the reason why Toyota made belted chains .. My wife’s Camry had a belted chain and it was dead quiet ..


Suspension changes do you need this ? ..

The simple answer is no .. Most of us don’t need to upgrade the suspension because most of us don’t go off road .. In all fairness, I am saying this in general because Cruiserheads are a different bread and off roading is why they sought out the Landcruiser in the first place and especially diesels because of driving range .. This is why most diesel cruiser have the highest number of long range tanks installed .. You won’t find nearly the number of folks running long range petrol tanks .. Since Cruiserheads are off roaders, most opt for 2-3 inch lift and improved suspensions .. Where they capitalize on ground clearance is not in the suspension it is actually in the taller tires ..


Does it make sense to increase turbo boost & add an intercooler ? .. How much boost .. ?

When increasing boost over stock boost how much more power do you need ? .. If you don’t plan to tow something then you probably don’t need to increase the boost from 12 lbs in my case to more than 20 lbs .. When you do increase the boost / engine output we will need to add additional cooling to the turbos boost air because a larger amount of heat will be introduced by the turbo .. An intercooler will be required to cool the air that is moved into the intake manifold .. It is important to choose an intercooler with a low pressure drop because the reason why you purchased a turbo is to provide more pressure .. An intercooler that is difficult to pass a high pressure of air through it will drop the pressure on the output side .. So it is important to select an intercooler that is matched to the boost pressure of the turbo to ensure lower losses across the intercooler .. Not overlooking the fuel system is one mistake that some do when increasing the boost .. By increasing the air charge into the cylinder without increase the fuel would mean that your engine would be running leaner .. While you can do this it also increases the temperature in which the fuel burns and the fuel would burn faster in this case .. You would not be seeing as much power increase if you increased the boost without increasing the fuel to bring the mix back into spec .. Just increasing the fuel pressure is not going to be sufficient .. Fuel injectors will also need to be changed when running over 15-18 lbs of boost (in my opinion, I don’t have good information that would prove this at this point) ..

More than 20 lbs means a bigger intercooler and most likely transmission modification and even higher boost levels might take a transmission fluid radiator in addition to the transmission mods .. Why would you want more power .. Lets say your pulling a 14 ft trailer and its heavy you might want to increase the boost .. Having a variable waste gate setting on the turbo means that you can find what turbo boost you really need for any given situation .. Its nice to have fuel economy and this would be part of that .. It is also important to mention that there are diminishing returns when running high boost with even larger injectors and higher fuel pressures .. The need for even cooler air into the intake will be very apparent at higher boost levels .. Will a Air to Air or Water to Air be sufficient in all cases .. The simple answer here is NO .. When outside ambient temperatures are high as they are in desert areas this will mean that running at high boost levels are not advisable due to head temperatures / engine overheating .. When running leaner at higher boost levels this problem becomes more serious .. Is there a way a to actually fix this running in desert conditions .. I believe there is .. I have found a Freon to Water Chiller made by a company in New Mexico (Killer Chiller) .. If I can get the water temperature dialed in and water flow rates into the intercooler dialed in we then are not dependent upon ambient air temperature like we are in a W2A & A2A Intercooler solutions which both require radiators and outside ambient air temps for their functionality .. This is why I don’t like ANY W2A or A2A because your limited by the environment .. What I would like to have is a F2W2A system that I can control the rate of flow of the water into the intercooler to have a constant air temperature ALWAYS ! .. Running boost of => 35 lbs this become very critical because the last thing we want are cracked valve seats and pistons .. Running lean at high boost increases the problem so inlet temps must drop drastically ..



Body, undercarriage protection, do you need this ? ..

Again, for the vast majority, the answer is still no .. Those who are offroaders yes this again is the pinch of prevention thing again .. Good bumpers, side bash bars, side bars over wheel wells connecting / welded to the side bash bars to the bumpers .. Undercarriage bash plates protecting engine / transmission .. Money well spent when you play hard / run over rough terrain ..


EMP Proof ? ..

Don’t laugh about this .. The fact that we haven’t had a nuclear war doesn’t mean that one can’t happen .. If there is one thing man excels in, it is stupidity .. After watching the presidential debates all I can do is shake my head .. In a single word .. Incivility .. All Mechanical Injection is a good thing .. The fact that computerized shifting in an automatic transmission is common, a manual transmission means an EMP proof vehicle .. Sorry for the spit balling .. I just wanted to touch all the bases because people who purchase diesel vehicles are more than likely Prep’ers ..

Why do I use the " .. " ? .. Imagine if you had a way to search the internet and find everything your wrote .. Imagine what if anyone else could find what you have written ? .. Imagine you don't want to hide what you have written so everyone know just exactly who you are and what you think .. I know of know man who has devise such a method .. .. .. .. .. .. .. .. ..
For those HAM's who know code .. KK6AFE ..
 
Joined
Aug 9, 2014
Messages
87
Location
USA
First off I must say that I am still learning and don't claim to be the ultimate authority or expert .. I am a mechanical engineer by trade but my area of engineering epertice was centered in the data center industry .. I have escaped commiefornia and am now located in New Mexico and plan to catch up on all the hunting and fishing I have been missing out on ..

On a comedic note California Gov Newsom the Gov who bankrupted the state has announced that all fossil fuel vehicles will be banned by 2035 .. With the increase of rolling blackout in the state, by 2035 there will be no power for electric vehicles .. I see the genius in this man ..

Now all comedy set aside ..

--

Why are Landcruiser Diesels Sought After by Landcruiser Enthusiasts ? ..

Diesel Engines are typically 10%-15% more efficient than Petrol Engines .. (Typically these are turbo’ed engines with 8-12 lbs of boost) .. Some of the much older very long stroke diesels were also efficient but they did not have turbos and ran at much lower rpm’s with much higher torque .. Wheel twisting power torque is king .. These older 1HD-T & 1HD-FT diesel engines don’t have EGR / Exhaust Gas Recirculation or DOC / Diesel Oxygen Catalyst and so the engines run cleaner and don’t have as much soot running into and out of their engines .. More soot = reduced life ..


What makes Diesel Engines attractive for Industrial use and Enthusiasts alike ? ..

Engine Stroke in high compression engines is typically longer & because of a longer burn cycle than that of a petrol engine. Additionally, Diesel engines can make up to 40% more torque than petrol engines which translates to more wheel twisting power at lower Rpm. Consequently, lower Rpm translates to less friction and lower operating temperatures in non-turbocharged engines .. For this to also be true with turbocharged engines, Intercoolers must deployed in higher turbo boost engines to decrease the Intake Temperatures caused by Turbocharging .. As Turbo pressures increase larger Intercoolers must be deployed to bring down air intake temperatures to operational levels .. By cooling the charge of air entering cylinders more oxygen & fuel can be mixed / burned per cycle increasing overall engine hp & torque .. Diesels can also be run leaner with higher efficiencies at higher boost levels but an decrease of inlet temperatures must be maintained .. Running leaner also means running cleaner but the down side is you can’t allow the inlet temperature be controlled by the ambient air .. I will address this later ..


What is the one thing you can do for Diesel that will increase engine life while increasing intervals between oil changes ?

I recently purchased a 1995 80 Series Landcruiser 24v strait 6 diesel vehicle .. The typical engine life of my cruiser is said to be on the order of 1 million km / 600k miles .. The oil change intervals are 4-5 km .. With an additional bypass oil filter which filters to 2 microns will increase engine life 25%-30% with the stock turbo setup .. An additional 25% increased life for a simple bypass filter we can see this is one of the best investments for a Diesel Engine as diesel engines combustion cycles produce more soot / carbon which enters the engine oil .. Carbon turns the engine oil black and is abrasive .. The increased friction from dirty oil increase surface wear .. Toyota could learn a thing or two about enlarging oil filters to filter down to 1-2 microns which would increase oil life by 3-4 times .. This translates to less frequent oil changes of ~16km / 10k miles between oil changes .. Would larger oil filters be worth it ? .. Yes, the savings in oil costs alone will easily pay off a 3x increase in very large oil filters and more importantly increase engine life .. This by far has the highest payoff of any other modification you do for your diesel engine or vehicle ..


Fuel availability ? ..

This is the current weak area when it comes to diesel engines .. To be fair, there is no path for bio-petrol .. That being said bio-diesel is a good hedge against fuel shortages .. There is a cash outlay for the chemical / tanks / pumps and bits to connect everything but the upside of not having fuel in a crisis makes bio-diesel very attractive .. Will a crisis like this happen in our lifetime ? .. It happened in the 1970’s in America .. When I was a teen I remember the gas lines and the days you could get a fill up .. So never say never ..


Transmissions why automatics over manual ? ..

Automatics really do better in rough terrain than manual transmissions .. This is pretty much the bottom line .. You will have some argument from some but by enlarge automatics take the human error out of the loop .. The down side to automatics is that most of them are adapted from Petrol engines which had much lower torque .. This was the major reason why Toyota didn’t have high boost on the earlier models .. The torque converters were not set up to run at higher torque levels and transmission temperatures suffered due to this, so much so Toyota added transmission fluid temp warning lights ! .. Surprisingly there are ways to fix this issue with diesel up to about 15-20 lbs of boost that doesn’t require a transmission fluid radiator .. A better valve body and torque converter are the two main fixes which have been produced and are upgrades you can get today .. Similarly there is a lockup kit for the higher gears to lock the automatic transmission higher gears to the engine .. This increases fuel economy and decrease tranny fluid temps in the high gears where elevated temps are common due to slippage .. This also increases transmission life which would help to match the engine life to the transmission life .. This in my humble opinion is worth the money as they say a pinch of prevention is worth a pound of cure .. It is also important to mention that transmission lock up devices allow you to use your engine as a brake .. This doesn’t increase the temperature of the transmission fluid .. I must also mention that 3r / 4th gear clutch wear is a real issue in the HDJ80 / 81 Landcruisers more so in the 81’s because of the A343F transmission is weaker in this area ..


Are there increased costs for servicing a diesel vehicle ? ..

Other than the oil issue which we have solved above .. No .. The costs of servicing are less than a petrol engine .. We don’t have sparkplugs to worry about .. The fact that the HDJ81 Diesel cruiser doesn’t have all the additional wiring a petrol engine has should see decreased costs for overall servicing .. There is one downside which makes no sense to me at all .. Why did Toyota using a timing belt when they pioneered belted chains and had used timing chains in petrol engines since the early 80’s ? .. This is probably one of the biggest design shortcomings Toyota has ever done .. At 100 km / 60k mile intervals this timing belt interval is one of the worst of the industry .. I had 1970’s vehicle with a timing belt and it was fairly large .. It was in fact about 30% larger than what is currently on my 1HD-FT motor and the engine was smaller (283 ci) .. This is why I have looked and I can’t find an aftermarket timing chain substitute for this engine .. The timing belt is the weakest design point of this engine .. You will notice that later Diesel engines by Toyota switched over to chains .. I am going to find a chain substitute for the timing belt which should more than double the change interval of the timing chain .. I would bet this would be a very popular upgrade that would make a very large number of us very happy .. I believe that chains of the right length already exist .. All that would need to be produced is the timing gears which shouldn’t be that hard to fabricate .. An existing chain would mean large numbers in production so low relative cost as opposed to a belt .. Chains by in large are more reliable .. Chains do make more noise hence this was the reason why Toyota made belted chains .. My wife’s Camry had a belted chain and it was dead quiet ..


Suspension changes do you need this ? ..

The simple answer is no .. Most of us don’t need to upgrade the suspension because most of us don’t go off road .. In all fairness, I am saying this in general because Cruiserheads are a different bread and off roading is why they sought out the Landcruiser in the first place and especially diesels because of driving range .. This is why most diesel cruiser have the highest number of long range tanks installed .. You won’t find nearly the number of folks running long range petrol tanks .. Since Cruiserheads are off roaders, most opt for 2-3 inch lift and improved suspensions .. Where they capitalize on ground clearance is not in the suspension it is actually in the taller tires ..


Does it make sense to increase turbo boost & add an intercooler ? .. How much boost .. ?

When increasing boost over stock boost how much more power do you need ? .. If you don’t plan to tow something then you probably don’t need to increase the boost from 12 lbs in my case to more than 20 lbs .. When you do increase the boost / engine output we will need to add additional cooling to the turbos boost air because a larger amount of heat will be introduced by the turbo .. An intercooler will be required to cool the air that is moved into the intake manifold .. It is important to choose an intercooler with a low pressure drop because the reason why you purchased a turbo is to provide more pressure .. An intercooler that is difficult to pass a high pressure of air through it will drop the pressure on the output side .. So it is important to select an intercooler that is matched to the boost pressure of the turbo to ensure lower losses across the intercooler .. Not overlooking the fuel system is one mistake that some do when increasing the boost .. By increasing the air charge into the cylinder without increase the fuel would mean that your engine would be running leaner .. While you can do this it also increases the temperature in which the fuel burns and the fuel would burn faster in this case .. You would not be seeing as much power increase if you increased the boost without increasing the fuel to bring the mix back into spec .. Just increasing the fuel pressure is not going to be sufficient .. Fuel injectors will also need to be changed when running over 15-18 lbs of boost (in my opinion, I don’t have good information that would prove this at this point) ..

More than 20 lbs means a bigger intercooler and most likely transmission modification and even higher boost levels might take a transmission fluid radiator in addition to the transmission mods .. Why would you want more power .. Lets say your pulling a 14 ft trailer and its heavy you might want to increase the boost .. Having a variable waste gate setting on the turbo means that you can find what turbo boost you really need for any given situation .. Its nice to have fuel economy and this would be part of that .. It is also important to mention that there are diminishing returns when running high boost with even larger injectors and higher fuel pressures .. The need for even cooler air into the intake will be very apparent at higher boost levels .. Will a Air to Air or Water to Air be sufficient in all cases .. The simple answer here is NO .. When outside ambient temperatures are high as they are in desert areas this will mean that running at high boost levels are not advisable due to head temperatures / engine overheating .. When running leaner at higher boost levels this problem becomes more serious .. Is there a way a to actually fix this running in desert conditions .. I believe there is .. I have found a Freon to Water Chiller made by a company in New Mexico (Killer Chiller) .. If I can get the water temperature dialed in and water flow rates into the intercooler dialed in we then are not dependent upon ambient air temperature like we are in a W2A & A2A Intercooler solutions which both require radiators and outside ambient air temps for their functionality .. This is why I don’t like ANY W2A or A2A because your limited by the environment .. What I would like to have is a F2W2A system that I can control the rate of flow of the water into the intercooler to have a constant air temperature ALWAYS ! .. Running boost of => 35 lbs this become very critical because the last thing we want are cracked valve seats and pistons .. Running lean at high boost increases the problem so inlet temps must drop drastically ..



Body, undercarriage protection, do you need this ? ..

Again, for the vast majority, the answer is still no .. Those who are offroaders yes this again is the pinch of prevention thing again .. Good bumpers, side bash bars, side bars over wheel wells connecting / welded to the side bash bars to the bumpers .. Undercarriage bash plates protecting engine / transmission .. Money well spent when you play hard / run over rough terrain ..


EMP Proof ? ..

Don’t laugh about this .. The fact that we haven’t had a nuclear war doesn’t mean that one can’t happen .. If there is one thing man excels in, it is stupidity .. After watching the presidential debates all I can do is shake my head .. In a single word .. Incivility .. All Mechanical Injection is a good thing .. The fact that computerized shifting in an automatic transmission is common, a manual transmission means an EMP proof vehicle .. Sorry for the spit balling .. I just wanted to touch all the bases because people who purchase diesel vehicles are more than likely Prep’ers ..

Why do I use the " .. " ? .. Imagine if you had a way to search the internet and find everything your wrote .. Imagine what if anyone else could find what you have written ? .. Imagine you don't want to hide what you have written so everyone know just exactly who you are and what you think .. I know of know man who has devise such a method .. .. .. .. .. .. .. .. ..
For those HAM's who know code .. KK6AFE ..
Good post.
 

bencallaway

SILVER Star
Joined
Sep 28, 2018
Messages
536
Location
Atlanta
How long did it take to write that and what motivated you? I read it twice. Fascinating.

edit: I read some of your other posts. Never mind.
 

mudgudgeon

SILVER Star
Joined
Dec 17, 2007
Messages
4,636
Location
Sydney, Australia
Two things

First.

I'll disagree with your opinion that automatic is superior to manual trans off-road. Particularly with a high torque diesel.
Diesel gives you excellent crawl control, and excellent compression braking for downhill speed control.
The only time I would say an automatic is superior is crawling up steep rocky terrain due to the torque converter.
With a diesel engine that produces low RPM torque without relying on boost, this is even less relevant.
Engines like the naturally aspirated 1HZ produce strong torque at low RPM and are great at crawling off-road


2nd thing,

you have the effects of fueling changes in a diesel misunderstood.

By increasing the air charge into the cylinder without increase the fuel would mean that your engine would be running leaner .. While you can do this it also increases the temperature in which the fuel burns and the fuel would burn faster in this case

This is back to front.
Forget what you know about the effect of lean or rich fueling from gas engines.
In a diesel, the effect is polar opposite.

A lean fuel mix means limited power.
A diesel engine idles because fuel mixture has been leaned out so there is just enough fuel to allow it run smoothly without stalling out.
Power output and RPM is increased by injecting more fuel.
A lean mixture in a diesel means low combustion temperatures.
A rich fuel mix means more power, BUT, there's no free lunch. More fuel burnt = more power, AND more combustion heat.
A turbo allows you to force additional air into the combustion process. This gives you a more compete burn of the fuel that's been injected, and leans out the air fuel mix and reduces combustion heat. The more complete misconception gives s small increase in power.
The big benefit of a turbo is the fact that having more air going in means you can inject more fuel, and increase power output, and keep combustion temps low.
Boost is your friend because it helps the engine run cooler.
Running a turbo diesel under a rich fuel air ratio condition for sustained periods is a sure way to kill a diesel.
For example, wide open throttle pulling a loaded trailer up hill, at low RPM.
You have a high engine load, low air flow, and dumping maximum fuel in. Combustion temps can rocket into dangerous territory.
If you're looking at increasing power output, I'd strongly recommend installing boost and exhaust gas temperature gauges, and understand the relationship and learn to drive the vehicle accordingly.
Diesels are happier working at high RPM with plenty of boost and air flow vs low RPM and limited air flow.


Most of the Toyota diesel engines can have power output increased by 50% or more without changing injectors and with a tune of the fuel pump settings.


Three - Intercooler.

Air to air is by far the simplest and least problematic / most reliable.
Front mounted intercooler is most efficient, and least susceptible to heat soak.

Air to air issues been proven to be good enough to deal with heat from turbo charge intake air on 40°C Australian conditions on 80 series with aftermarket turbo's running 20+ psi boost and towing heavy loads.
Air to air as quicker to shed heat if the system becomes heat soaked than water to air due to the big thermal mass of water.

Ultimately, a water to air system still needs to shed the same amount of heat back to the atmosphere via a radiator.
With water to air, you're just adding in a load of failure points and complication into the system with pumps, wiring, heat exchanger etc
There is some advantages to water to air, IMO the complexity outweighs the benefits.

D -

check out the diesel tech section of the forum if you haven't already there's loads of great info on turbo options, intercooler, fuel pump upgrades and tuning

There's a bunch of highly knowledgeable people with diesel under their skin in the diesel tech section
 
Joined
May 26, 2008
Messages
285
Location
Leduc County
Automatics are superior off-road for the same reasons trucks and heavy equipment use them. Power is converted to torque at low speeds and heavy loads.

The timing belt is a serious failure point. When it goes it is catastrophic. Every valve will bend and you will need new heads, possibly a piston or 2, hopefully that's it.

For driveability the 1HD-T is a dog on the highway if you have an armoured up trail rig. Don't even think about passing a tractor-trailer without a five-mile window. RHD is a PITA and the diesel just makes it more so. Great for offf-roading. For Expeditions not so much.

Most parts need to come from Australia so expect to pay those crazy shipping costs for everything.

My experience anyway. FWIW
 
Joined
May 26, 2008
Messages
285
Location
Leduc County
Disagree...stock I'd take one over a stock 1FZ any day of the week and more so with a bit of a basic tickle. Did you by any chance have an auto box, stock diff gears and larger tyres?
Yes. Stock 4.10 gears. No engine mods. I did drive a re-geared manual though that showd some zip.
 

mudgudgeon

SILVER Star
Joined
Dec 17, 2007
Messages
4,636
Location
Sydney, Australia
Just super confused how a Diesel engine can be considered to have good compression braking without extra valve train components getting involved is all.
The HD-T runs 22:1 compression. On a 4.2 litre engine, that is significant amount of compression braking. Maybe engine braking is a more correct term?

Driving them in normal conditions with a manual, if you suddenly lift off the throttle completely, they prop hard!

Offroad steep decent technique is to use 1st gear low range, let the engine idle. Left foot PLANTED on the floor, NEVER on the clutch.
At idle it will walk down all but the steepest inclines without much foot braking effort at all.

On really steep stuff, at times braking will stall out the engine. In these circumstances, you can often continue your descent with the engine still turning over, still providing compression braking, left foot PLANTED ON THE FLOOR, NO DE-CLUTCH.
Or you can use engine braking, and got braking to bring the vehicle to a stop. Then use the key to turn over the engine, and continue driving, all without lifting your left foot off the floor.
(Google off-road key-starts)
They give you a huge amount of crawl control, all with very little use of brakes, particularly in comparison to a heavy, auto, gas engined beast.
 

swankstar

SILVER Star
Joined
Jul 20, 2017
Messages
447
Location
Boise, Idaho
The HD-T runs 22:1 compression. On a 4.2 litre engine, that is significant amount of compression braking. Maybe engine braking is a more correct term?

Driving them in normal conditions with a manual, if you suddenly lift off the throttle completely, they prop hard!

Offroad steep decent technique is to use 1st gear low range, let the engine idle. Left foot PLANTED on the floor, NEVER on the clutch.
At idle it will walk down all but the steepest inclines without much foot braking effort at all.

On really steep stuff, at times braking will stall out the engine. In these circumstances, you can often continue your descent with the engine still turning over, still providing compression braking, left foot PLANTED ON THE FLOOR, NO DE-CLUTCH.
Or you can use engine braking, and got braking to bring the vehicle to a stop. Then use the key to turn over the engine, and continue driving, all without lifting your left foot off the floor.
(Google off-road key-starts)
They give you a huge amount of crawl control, all with very little use of brakes, particularly in comparison to a heavy, auto, gas engined beast.
So you’re talking about engine turning while the fuel is cut off by the ignition? I can see that as a thing, but engine/compression braking in a running engine come from the butterfly plates in a carb or equivalent in a throttle body creating vacuum, which most turbo diesels aren’t going to have (not sure about Toyota diesels) since limiting air for a diesel is a pretty bad idea (until you get into egr and def and other weird aspects of diesels, like Fords or something).
 

SNLC

OCD
Supporting Vendor
Joined
Sep 9, 2004
Messages
7,144
Location
Boise - Idaho
The HD-T runs 22:1 compression. On a 4.2 litre engine, that is significant amount of compression braking. Maybe engine braking is a more correct term?

Driving them in normal conditions with a manual, if you suddenly lift off the throttle completely, they prop hard!

Offroad steep decent technique is to use 1st gear low range, let the engine idle. Left foot PLANTED on the floor, NEVER on the clutch.
At idle it will walk down all but the steepest inclines without much foot braking effort at all.

On really steep stuff, at times braking will stall out the engine. In these circumstances, you can often continue your descent with the engine still turning over, still providing compression braking, left foot PLANTED ON THE FLOOR, NO DE-CLUTCH.
Or you can use engine braking, and got braking to bring the vehicle to a stop. Then use the key to turn over the engine, and continue driving, all without lifting your left foot off the floor.
(Google off-road key-starts)
They give you a huge amount of crawl control, all with very little use of brakes, particularly in comparison to a heavy, auto, gas engined beast.

I agree with you and that the diesel is better for this.

However I often drive my auto like a manual. Off-road, 1st-low does not require me to brake and when it does I tap the brakes.

Sure, some people just stick it in drive and brake to slow down. They are missing a lot of driving experience and wearing out their brakes a lot faster than needed.

Cheers
 

mudgudgeon

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No, I'm talking about any special valve train parts.
I'm talking about using the 22:1 compression of every pot full of air to slowdown the engine, and the vehicle speed.

Diesel has no butterfly/throttle in the intake, so every cylinder is completely filled on the intake stroke every time the engine cycles.
This full pot of air is compressed. If you add minimal fuel, the engine will just turn at idle speed. A small amout of foot brake keeps gravity in check.
Compared to a gas engine at 9 or 10:1 commission, and butterfly throttle in the intake, at idle cylinders are far from full of air, so there's far less compression on both counts.

If you stall out the engine, but keep the clutch engaged, it will still draw in 700ml per pot every time that cylinder cycles, it still gets compressed at 22:1, and provides a lot of braking
 
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I believe the 1HZ has 22:1 compression, the 1HD-T, because it is turbo'd is only 18-19:1. The amount of compression braking you get out of an engine is almost entirely due to valve timing. When the engine compresses a charge of air, the exhaust valve doesn't let out the fully compressed charge. Instead, it waits until the piston is basically at the bottom of its stroke to open the exhaust valve and release the air. Most of what you feel when coasting on the engine is frictional and flow losses. Big trucks use either compression brakes, which alters the exhaust valve timing to release a near fully compressed charge, or an exhaust brake, which causes a restriction in the exhaust, thereby increasing flow losses.
 

mudgudgeon

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Matt does a good explanation of a hill start / key start.

I've used this technique many times.
It can also be used for a steep forward descent where you want to travel slower than the running engine will allow. Stall out the engine, key start in gear when you're ready to proceed.
 

mudgudgeon

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I believe the 1HZ has 22:1 compression, the 1HD-T, because it is turbo'd is only 18-19:1.

I think you're right, but kind of splitting hairs.

I believe the 1HZ has 22:1 compression, the 1HD-T, because it is turbo'd is only 18-19:1. The amount of compression braking you get out of an engine is almost entirely due to valve timing. When the engine compresses a charge of air, the exhaust valve doesn't let out the fully compressed charge. Instead, it waits until the piston is basically at the bottom of its stroke to open the exhaust valve and release the air. Most of what you feel when coasting on the engine is frictional and flow losses. Big trucks use either compression brakes, which alters the exhaust valve timing to release a near fully compressed charge, or an exhaust brake, which causes a restriction in the exhaust, thereby increasing flow losses.

The key is that during the compression stroke, bith valves are closed, compression of a full pot of air to 18,19, 22:1 gives a significant amount of braking at crawling speeds.
 

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