Offroad-Express

A bit of History and upgrades already done.
The reason for the upgrades is to get the best tow wagon that I can from an 80 series cruiser with a 1HDT engine and 4 speed auto.
Mods already done:
6" suspension lift.
35" tyres
Diff ratios changed too 4.88's with ARB diff lock in rear.
Trans cooler
I think its a 2.5" exhaust with exhaust brakes.
Running 3 Auberins digital gauges with alarms:-
Trans temp set at 115degC
EGT set at 720 degC pre turbo.
Boost gauge alarm set at 15psi
Running a turbo Boost tee set at 13psi.
Fuel wound up a bit and off boost fuel set at maximum which I need to get rolling.

I tow a 3.5T boat.
On the hill climbs I find I'm feathering and easing off the throttle all the way up to keep the EGT's down. Changing down gears as required. I try to keep it in 4th for as long as possible as this keeps my trans cool. Once down into 3rd trans temp rises quickly so I tend to skip 3rd and go straight to second. Trans temp dosn't rise as quickly and its easier to manage the EGT's. Towards the end of some hill climbs I find I have to finish off in first gear to keep trans temp out of alarm. Or the other option is to stop and select low range. I have disconected the centre diff lock so it doesn't automatically engage on low range selection. This means I can tow in low range right up into 4th gear on the hills with low EGTs and the trans temp comes right back. The only problem with this is that I have to keep stopping and starting to go between high and low range when I have a small down hill run during the hill climb or just go slow in low range during that period.
So are there any other upgrades I can do to obtain more power while keeping EGTs and trans temp down before I look at a v8 diesel conversion.
I can manage with what I have but its always nice to do better.
Upgrades to consider and what gains I could expect to get.
Bigger exhaust (suspect I would need to do the dump pipe)
Intercooling of some sort.
Possibly bigger trans cooler.
What boost can I safely run with standard turbo?
Turbo upgrade (need info)
What revs can I safely rev one of these engines too. Reason I ask is that when in 2nd gear I find EGTs stay down but I still keep off the throttle so I don't over rev it. Because I'm easing off the throttle and the closer it gets to that labouring zone EGTs climb. Also means It takes longer to get up the hill which means more temp in the trans or going into first. Thinking if I can keep maximum revs and speed for longer it would be better.
Also what gains would I get if I went to a more modern cruiser 6 cylinder engine and would it need to be certed if it was still a 4.2 diesel. Also would it bolt straight in. If not what mods would be needed.
Lots to consider so looking forward to lots of opinions on the best path to take.

Use "Search" there was recent discussion on intercooling them. I think "Hachi_Roku" is selling a kit for them.
Have you given it a thorough service recently? Had the injectors freshened up?
It doesn't sound right to me that it has that much trouble with that load. Ask PeteFJ thingee about his 80's, he had a large boat and an 80.

One thing you may wish to consider is getting a heavy duty / tow torque converter for the auto. (They do them is Aussie) As said you are generating a lot of heat in the auto...
There are places around which will overhaul it and tighten up the clearences amoung other things... This will increase its effeiency and reduce the slip... This slip is whats generating the heat and sucking out the power.. The engine should have pleanty of beans to tow 3.5T....

I also saw a company doing valve bodies for the 80 series auto trans which were modified, converter lockup in third gear was one of the mods. might be worth looking into.

Diorama wrote:The reason for the upgrades is to get the best tow wagon that I can from an 80 series cruiser with a 1HDT engine and 4 speed auto.
Mods already done:
6" suspension lift.
35" tyres
Diff ratios changed too 4.88's with ARB diff lock in rear.

Fuel wound up a bit and off boost fuel set at maximum which I need to get rolling.

I tow a 3.5T boat.

You are using a brick raised 6 inches with 35 inch tyres trying to tow 3.5 ton. Of course gearbox is going to heat up with gearing like that.

If you want a good tow wagon, get it back down lower on tyres with less rolling resistance that don't gear it up so high on road.

Or get auto and torque converter rebuilt/replaced with one that is valved to suit the vehicle and load demanded.

as per my reply in the other thread.

Cool the intake charge = power and cooling
add water & meths injection = power and internal cooling

Smaller tyres, straight up they will make a huge difference as has already been said it will lower the gearing and take the pressure of your trans

Suza wrote:Smaller tyres, straight up they will make a huge difference as has already been said it will lower the gearing and take the pressure of your trans

Are you people even reading? He has 4.88 ratio diffs. Slightly undergeared for 35's.

Sounds like your trans is old and sloppy and you don't have an efficient transcooler installed.

13psi is relatively low for a 1hdt considering factory ranges between 9 and 14, however this only affects your egt's. Anything higher will start to defuel the pump anyway unless you get it modified to remove this function.

Standard turbo's are not really all that efficient. Get what they call a gturbo from aus or find someone to modify yours here.

2.5" exhaust too small. Get a rage 3" dump pipe back.
720deg is still pretty low. Its safe to get up to 800deg but its long periods of time at these temperatures that kills them. I back off at 800deg.

You can't over rev it. They have governers in the pump to stop this happening. Its just not efficient to be over 3000rpm in a 12v.

Get an efficient intercooler. This with a larger or modified turbo will keep egt's down.

There are so many things you can do to make these things go better. What ive listed above is only a small list of things. Good luck

churchill wrote:I also saw a company doing valve bodies for the 80 series auto trans which were modified, converter lockup in third gear was one of the mods. might be worth looking into.

Convertor lock up is definatly worth looking at. 3rd gear is where most of the heat gets generated.

turoa wrote:

Suza wrote:Smaller tyres, straight up they will make a huge difference as has already been said it will lower the gearing and take the pressure of your trans

Are you people even reading? He has 4.88 ratio diffs. Slightly undergeared for 35's.

Sounds like your trans is old and sloppy and you don't have an efficient transcooler installed.

13psi is relatively low for a 1hdt considering factory ranges between 9 and 14, however this only affects your egt's. Anything higher will start to defuel the pump anyway unless you get it modified to remove this function.

Standard turbo's are not really all that efficient. Get what they call a gturbo from aus or find someone to modify yours here.

2.5" exhaust too small. Get a rage 3" dump pipe back.
720deg is still pretty low. Its safe to get up to 800deg but its long periods of time at these temperatures that kills them. I back off at 800deg.

You can't over rev it. They have governers in the pump to stop this happening. Its just not efficient to be over 3000rpm in a 12v.

Get an efficient intercooler. This with a larger or modified turbo will keep egt's down.

There are so many things you can do to make these things go better. What ive listed above is only a small list of things. Good luck

Trans is not old and sloppy. It had a complete overhaul a few years ago. $4500 spent on it. I think I could probably go to a bigger cooler.
Sounds like a bigger exhaust is on the cards. I had looked at inter cooling but was trying to avoid if possible. The cost of that is fairly high and it sounds like I would still have to do alot of other mods as well. So thought I might try other things first to see if it improves.
I've always backed off when EGT hits 720. From what I've read thats the max sustainable temp. Sometimes take it a bit higher for a short period. I want this vehicle to last me a long time so drive very conservatively when towing.
Would like to no more about better turbos and what sort of gains I could expect to get.
Interesting you say factory boost ranges from 9-14 psi. I'm sure my manual said set point was 10psi. When I fitted the boost gauge it was bang on 10psi.
I would like to consider boosting it more but not sure what it could handle.
I usually back of the throttle at around 3-3300 revs

turoa wrote:

Suza wrote:Smaller tyres, straight up they will make a huge difference as has already been said it will lower the gearing and take the pressure of your trans

13psi is relatively low for a 1hdt considering factory ranges between 9 and 14, however this only affects your egt's. Anything higher will start to defuel the pump anyway unless you get it modified to remove this function.

Not sure what you mean by modifying to remove this function.
Thought I could just wind the fuel up to compensate for more boost.
I understand more boost cooler engine. More fuel hotter engine. So its a compromise to find the best set point between the two. Obviously it can only handle so much boost which is what will limit my fuel input. What I need to know is how much I can safetly boost it by. Keeping in mind I don't want to kill it.

callum007 wrote:Use "Search" there was recent discussion on intercooling them. I think "Hachi_Roku" is selling a kit for them.
Have you given it a thorough service recently? Had the injectors freshened up?
It doesn't sound right to me that it has that much trouble with that load. Ask PeteFJ thingee about his 80's, he had a large boat and an 80.

Don't get me wrong it has plenty of get up and go. But its the same old story once you put gauges in you relise you shouldn't be using all the power at your finger tips.

Trying to get my head around whether a 3" exhaust will help me in my hill climbs with the boat on. The turbo would spool up quicker when taking off from a standing start but what gains could I expect to get when towing up hills.

skid wrote:LPG fuming.

Been thrashed on this site before.

Search it out

On the subject of EGTs, the first thing I would try if it were my truck, is turning the max fuel back a little bit, and adjusting the waste gate to stay closed longer.

You want all the air you can get from the turbo. It will keep the burn cool.

No point dumping heaps of fuel in, if the waste gate stops the turbo from making useful boost to burn it properly with. It just creates heat.

I would even bypass the waste gate altogether and see if that helps your egts, then you know your on the right track.

^^ this makes sense, try tuning it first. Also when air is compressed it heats up, this is where an intercooler comes into play and takes heat out of the charge air before it goes into the engine. I'm new to diesels but there's a reason most new diesels have intercoolers.

Afaik the ct26 turbo used on your motor is definatley not the mosr efficent example. Also anything over 18psi and they are just an air heater. Imo after a 3in exhaust and intercooler you should be really looking at a more efficent turbo. In my.experiance I have found the tdo5 a good quality turbo but I would be going and talking to a reputable desiel turbo guy and go through options with them.
Also the trans lock up would be a really good idea.

Diorama wrote:I had looked at inter cooling but was trying to avoid if possible. The cost of that is fairly high and it sounds like I would still have to do alot of other mods as well.

Would like to no more about better turbos and what sort of gains I could expect to get.

The cost of intercooling is not high. Especially if you're talking about doing an engine swap. Im not sure why you would need to do more mods for an intercooler? Intercooler lowers EGT and increases power slightly due to the colder air, but in a diesel the lower you can get your EGT's, the more fuel you can throw in, and the more power you can make. Intercooling and boost is what you want.

Turbo wise there's quite a few people that play with them. I don't know too much about the ct26's as mine blew up so I threw it away and put an aftermarket turbo on. One of the more well known ones it a 'gturbo' from australia. Search google for this, or this forum for more options as its been covered many times before.

Diorama wrote:Not sure what you mean by modifying to remove this function.
Thought I could just wind the fuel up to compensate for more boost.
I understand more boost cooler engine.

The boost compensator consists of what people call a fuel pin or rod. This has a taper on it to add more fuel in as the boost goes up. However it gets to the point where it has a reverse taper to defuel after a certain pressure. This seems to be around the 15psi mark.

Despite what some people will tell you, once you go above this, tuning becomes very difficult because it is defueling. Have done back to back dyno runs at 18psi and 15psi and at a lower boost it was producing more power. You can see it if you actually look at fuel rod. You can also see it on EGT gauges where if you have your foot up it, up a hill, the EGT's will climb and then start to fall again.

Diorama wrote:Trying to get my head around whether a 3" exhaust will help me in my hill climbs with the boat on. The turbo would spool up quicker when taking off from a standing start but what gains could I expect to get when towing up hills.

Lower EGT's. Which is pretty much the name of the game.

DieselBoy wrote:On the subject of EGTs, the first thing I would try if it were my truck, is turning the max fuel back a little bit, and adjusting the waste gate to stay closed longer.

You want all the air you can get from the turbo. It will keep the burn cool.

No point dumping heaps of fuel in, if the waste gate stops the turbo from making useful boost to burn it properly with. It just creates heat.

I would even bypass the waste gate altogether and see if that helps your egts, then you know your on the right track.

Already tried turning the fuel back but It wouldn't idle so I think the fuel adjustment is spot on.
I feel as though I just need more but cooler air so I can increase the fuel

I honestly wouldnt be doing anything before doing an intercooler.

Cooler air, means denser air. which in turn means more efficient combustion.

Cools down egts, increases power and depending on setup shouldnt cost over 500.

Plenty of second hand intercoolers around, even if its a top mount with a fan underneath, you should get change out of 200 bucks.

Also, i dont see how dropping down to smaller tyres wouldnt help.

i could see where it would be a dis advantage on flat, because you would be doing higher revs to stay at the same speed. but when it comes to hills, the lower the ratio the better, specially when pulling heavy loads, why do you think trucks run around with smallish tyres and diff ratios around 5:1

Diorama wrote:I had looked at inter cooling but was trying to avoid if possible. The cost of that is fairly high and it sounds like I would still have to do alot of other mods as well.

Would like to no more about better turbos and what sort of gains I could expect to get.

What sort of budget are you looking to spend, considering you think a intercooler setup is expensive are you dreaming of great performance for not much coins?

A decent turbo will cost more than a cooler setup

Dirtydog wrote:I honestly wouldnt be doing anything before doing an intercooler.

Cooler air, means denser air. which in turn means more efficient combustion.

Cools down egts, increases power and depending on setup shouldnt cost over 500.

Plenty of second hand intercoolers around, even if its a top mount with a fan underneath, you should get change out of 200 bucks.

Also, i dont see how dropping down to smaller tyres wouldnt help.

i could see where it would be a dis advantage on flat, because you would be doing higher revs to stay at the same speed. but when it comes to hills, the lower the ratio the better, specially when pulling heavy loads, why do you think trucks run around with smallish tyres and diff ratios around 5:1

I agree with the tyres but I still use it for 4x4 as well so its finding the best compromise. I looked into intercoolers a while ago but am still on the fence as to which sort but was swayed towards a front mount but its getting one that will fit with my trans cooler bull bar and winch. I know I will have to do it at some stage.

trucked wrote:

Diorama wrote:I had looked at inter cooling but was trying to avoid if possible. The cost of that is fairly high and it sounds like I would still have to do alot of other mods as well.

Would like to no more about better turbos and what sort of gains I could expect to get.

What sort of budget are you looking to spend, considering you think a intercooler setup is expensive are you dreaming of great performance for not much coins?

A decent turbo will cost more than a cooler setup

Not worried about the budget. I'm happy to do whats necessary but don't want to throw money away for no gains

Okay so it looks like I definatly need to do 2 things. Exhaust and intercooler.
Which order. I still can't see how a bigger exhaust will achieve lower EGTs on hill climbs. I can see how it would boost up earlier from a standing start but once at maximum boost on a hill climb I can only pump so much hot air into it. The only way I can see to get the EGTs down is buy putting more or cooler air into it. I must be having a vacant moment but I just can't see how a bigger exhaust will reduce EGTs on its own. Unless I'm not getting maximum boost while hill climbing. I'm taking the boat away this weekend so I'll take more notice of what the boost is doing when climbing hills. Really would like a good explanation on this.
It also sounds like a better turbo may not be the way to go if I'm limited by my injector pump. Will this be money wasted if my injector pump can only pump enough fuel to cover up to 15psi boost.

turoa wrote:

Diorama wrote:I had looked at inter cooling but was trying to avoid if possible. The cost of that is fairly high and it sounds like I would still have to do alot of other mods as well.

Would like to no more about better turbos and what sort of gains I could expect to get.

The cost of intercooling is not high. Especially if you're talking about doing an engine swap. Im not sure why you would need to do more mods for an intercooler? Intercooler lowers EGT and increases power slightly due to the colder air, but in a diesel the lower you can get your EGT's, the more fuel you can throw in, and the more power you can make. Intercooling and boost is what you want.

Turbo wise there's quite a few people that play with them. I don't know too much about the ct26's as mine blew up so I threw it away and put an aftermarket turbo on. One of the more well known ones it a 'gturbo' from australia. Search google for this, or this forum for more options as its been covered many times before.

Diorama wrote:Not sure what you mean by modifying to remove this function.
Thought I could just wind the fuel up to compensate for more boost.
I understand more boost cooler engine.

The boost compensator consists of what people call a fuel pin or rod. This has a taper on it to add more fuel in as the boost goes up. However it gets to the point where it has a reverse taper to defuel after a certain pressure. This seems to be around the 15psi mark.

Despite what some people will tell you, once you go above this, tuning becomes very difficult because it is defueling. Have done back to back dyno runs at 18psi and 15psi and at a lower boost it was producing more power. You can see it if you actually look at fuel rod. You can also see it on EGT gauges where if you have your foot up it, up a hill, the EGT's will climb and then start to fall again.

Diorama wrote:Trying to get my head around whether a 3" exhaust will help me in my hill climbs with the boat on. The turbo would spool up quicker when taking off from a standing start but what gains could I expect to get when towing up hills.

Lower EGT's. Which is pretty much the name of the game.

So that means upgrading my turbo won't do any good as I won't be able to poke any more fuel at it.

If you dont want to go and replace the whole pipe, you could get a turbo sock or some exhaust wrap to keep the gasses hot so they exit faster (dont know how much truth there is in this) but either way it should slightly reduce the under bonnet temps.

Go with a top mount and a fan underneath, or a water to air intercooler. with a front mount your making a whole lot more volume that the turbo has to compress due to extra piping etc, and at slow speeds, a water to air or a fan underneath will be able to get rid of the heat easier.

Water to air you get the benefit of having a radiator up front, but the advantage of not having all the extra pipe. you can pick up a subaru water to air intercooler, and get it modified pretty easy to suit your needs.

Dirtydog wrote: with a front mount your making a whole lot more volume that the turbo has to compress due to extra piping etc, and at slow speeds, a water to air or a fan underneath will be able to get rid of the heat easier.

spoken like a true keyboard mechanic......

do the maths for a 1HDT and CT26, work out the volume of air it ingests then calculate how long at 1500rpm it takes to inhale the air volume of a 450x230 intercooler and 2-2.5 metres of 2 inch pipe.

you may find it hard to believe but there is no lag, and in most cases it actually comes on boost faster due to the air being cooler.

intercoolers parked on top of a motor do 1 thing, and that is heat up. no amount of ducting or fans will ever make them cool as much as a front mount.

Dirtydog wrote:Im the new ORE intercooler expert.

The guy wants cooling whilst towing. So he is moving. Front mount will work fine. Like STRX7 says (who I believe has IC kits for sale), stop giving mis informed advise. If space were an issue on an 80 or he has a dirty big winch etc on the front, then water to air, but its not so a mid sized front mount will be the way to go.

DO the exhaust first. Then IC, or both at once, Don't buy a shitty second hand IC cos its cheap, someone is selling it as its no good for them anymore. Buy quality first off http://hpdiesel.com.au/ or PM "hachi_roku" as he is importing the same kit direct I believe.

Didnt know that about front mounts, once again just going off what people have told me.

i know that the extra meter worth of pipe makes a hell of a difference when it comes to performance cars, probably not enough of a difference to notice with a 4x4.

if you guys are going to start this again, good for you, im just trying to help

Iv'e been down the intercooler path before (you will see in my previous threads) and pretty much decided on a Northside 4x4 water to air kit (unless someone convinces me otherwise) as they have a radiator that will fit on one side of the centre bonnet latch support. My trans cooler is on the other side so everything is pretty tight.
Questions I'm still seeking explanations on is:

How will a bigger exhaust reduce my EGT's when towing. I thought it would just spool the turbo up faster from a standing start.

Is an upgraded turbo going to help with the standard injector pump. With the extra PSI will I be able to put enough fuel in. I've heard claims of 22psi. This will definatly help my EGTs once I keep that air cool with an intercooler but will I be able to chuck enough fuel at it to compensate.

Also I'm looking at the trany conversion to get 3rd gear lock up. I know this will help as 3rd cooks my trany on hill climbs and has just become something I have to pass through from 4th to 2nd. More info on the best place to get the valve block would be useful.