How much power increase is there in the 3L upgrade? (1 Viewer)

[LeonLJ78]

Hi,

Looking into options and what i would need to know if i upgrade the 2lte to gain more power in my LJ78.

First really wanting to know from someone with the experience of doing it, would i really see difference/ increase between my current 2lte with intercooler and 12psi boost. to a 3L (and changing all turbo/ intercooler parts over) would actually make. My goal with be more power on the hills while towing etc, possibly change the shoes and push some 33's at the same time.

Also as the what am i in for to get her running regarding fuel/ ecu etc? or is it a fairly simple swap.

Ive seen some threads recommending the 3L but really not to much about the power increase etc.

 

[AirheadNut]

Not sure that you'd end up with much more power. If you have a new head on your 2L-TE you'll be best off tuning that, they can make decent power and have a stronger bottom end than a 3L. With an intercooler already in place you should be able to do a few mods, up the boost to 15+psi and add some fuel. Here are a couple of threads to peruse if you haven't seen them already:

Ideas for improving the 2LTE

Updated February 23, 2016 I own an LJ78 Landcruiser Prado (2LTE), and I love it. These vehicles are very well built and generally as tough as other cruisers with the exception of the small IDI turbo diesel 2LTE engine. I feel they are one of the most undervalued and unappreciated cruisers out...

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New Member in Victoria, LJ78

Thought I should properly introduce myself here. I've been pretty active in the 70 series forum, but have not posted much here. I live in Victoria BC. Wanted a 70 series LWB. Couldn't afford a heavy duty HZJ77 rig, so decided to try the light duty LJ78 model. Got a great deal ($3500) on a...

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[GTSSportCoupe]

The only advantage is a tiny bit of extra displacement (like 17% more). However you'll get higher compression weaker pistons that take less boost. Rods might be weaker too.... And you'll have to modify the 3L injection pump to provide more fuel as boost increases (boost compensator). Personally no advantage here in my opinion. Oh, almost forgot, the 3L camshaft breaths a bit better, but you can swap one into your 2LT if you want (I have).

Ultimately, the power limit with these motors is the 10mm injection pumps and how much air you can pump into them. It's all in the tuning. I've got my pump turned up as much as possible and am running around 19psi after the intercooler. That's enough for about 100whp or 145bhp. Only way to beat that would be upgrading to a 12mm (1KZT?) injection pump and an aftermarket turbo capable of high pressure ratios. Stock these put down about 45whp FYI.

Here is a picture of a before/after dyno for a turbo 3L engine (whp through a more efficient (hilux) t-case than a landcruiser split one):

 

[LeonLJ78]

The only advantage is a tiny bit of extra displacement (like 17% more). However you'll get higher compression weaker pistons that take less boost. Rods might be weaker too.... And you'll have to modify the 3L injection pump to provide more fuel as boost increases (boost compensator). Personally no advantage here in my opinion. Oh, almost forgot, the 3L camshaft breaths a bit better, but you can swap one into your 2LT if you want (I have).

Can you tell me more about the cam change? noticeable benefit and other things that need to change to make them perform etc.?

 

[GTSSportCoupe]

The cam shaft helped my motor breath a bit better at higher rpms, but really it is probably the most minor power upgrade I've done.

These motors really wake up when you go above 17psi. You've already intercooled yours which is the most important thing. Make sure your cooling system is in excellent shape (service your clutch fan with new oil too). I also recommend removing the EGR and the main throttle plate if you have not already. Make sure the intake manifold and intake ports to they cylinder head are clean.

You will need a Pyrometer to monitor your EGT's before you start messing with the tuning.

Buy a manual boost controller for the turbo and basically crank it up as high as it'll go. The CT20A turbo runs the same shaft size and bearing parts as a CT26, but it's a much smaller turbo. Basically it can take a real beating. The 2LTE injection pump can only provide enough fuel for your turbo to make about 20psi maximum anyhow.

Turn the spill control valve screw (on your injection pump) in about 3/4 turn. Don't go further or you risk a run away diesel. Rev your motor while parked to make sure this does not happen. If it does, just turn the screw back out a bit until it stops. It's a bit scary but not the end of the world. Happened to me at about 1 full turn in.

Now you have to trick the ECU into not going into unhappy mode when you run over 15psi. You can do this a couple different ways. Some have used a 4.3V zener diode on the output to the ECU to limit it. Personally I've used a bleed valve to lower the boost curve so even though I'm hitting 19-20 psi, the computer thinks I'm only hitting 15psi maximum.

So basically you can make WAY more power than you are now just by tuning your engine.

If your EGT's are high after all this, increase your exhaust size and dump pipe size. Also make sure your intercooler is setup to be efficient (front mount with good airflow and a good sized core).

If you want to know more about how to do these things just do some searching on this site. There are lots of threads about all these items.

 

[LeonLJ78]

The cam shaft helped my motor breath a bit better at higher rpms, but really it is probably the most minor power upgrade I've done.

These motors really wake up when you go above 17psi. You've already intercooled yours which is the most important thing. Make sure your cooling system is in excellent shape (service your clutch fan with new oil too). I also recommend removing the EGR and the main throttle plate if you have not already. Make sure the intake manifold and intake ports to they cylinder head are clean.

You will need a Pyrometer to monitor your EGT's before you start messing with the tuning.

Buy a manual boost controller for the turbo and basically crank it up as high as it'll go. The CT20A turbo runs the same shaft size and bearing parts as a CT26, but it's a much smaller turbo. Basically it can take a real beating. The 2LTE injection pump can only provide enough fuel for your turbo to make about 20psi maximum anyhow.

Turn the spill control valve screw (on your injection pump) in about 3/4 turn. Don't go further or you risk a run away diesel. Rev your motor while parked to make sure this does not happen. If it does, just turn the screw back out a bit until it stops. It's a bit scary but not the end of the world. Happened to me at about 1 full turn in.

Now you have to trick the ECU into not going into unhappy mode when you run over 15psi. You can do this a couple different ways. Some have used a 15V zener diode on the output to the ECU to limit it. Personally I've used a bleed valve to lower the boost curve so even though I'm hitting 19-20 psi, the computer thinks I'm only hitting 15psi maximum.

So basically you can make WAY more power than you are now just by tuning your engine.

If your EGT's are high after all this, increase your exhaust size and dump pipe size. Also make sure your intercooler is setup to be efficient (front mount with good airflow and a good sized core).

If you want to know more about how to do these things just do some searching on this site. There are lots of threads about all these items.

are you able to send me a photo of the bleed valve set up, ive read the fuel adjustment treads so have an idea on that. just not sufre about how the boost bleed it set up.

and is this the sort of unit you mean/ have installed? US $3.32 5% OFF|Airflow Speed Control 8mm OD Hose Tube Push to 1/4

The SL8-02?

 

[malteser]

How do you guys know that the 3L has weaker pistons/bottom end when compared to a 2LT ? I have seen both engines disassembled and there isn't much difference between their components, the pistons actually look almost exactly the same with same crown design and same skirt height. I've seen stock 3L motors running over 20psi boost for 100k km and still going. Boost doesn't kill diesels, its the heat that does. I can't give any exact figures but all I can say is my LJ79 with turboed 3L feels more powerful then my mates LJ70 with 2L-T and we're both running similar setup and boost.

 

[GTSSportCoupe]

How do you guys know that the 3L has weaker pistons/bottom end when compared to a 2LT ? I have seen both engines disassembled and there isn't much difference between their components, the pistons actually look almost exactly the same with same crown design and same skirt height. I've seen stock 3L motors running over 20psi boost for 100k km and still going. Boost doesn't kill diesels, its the heat that does. I can't give any exact figures but all I can say is my LJ79 with turboed 3L feels more powerful then my mates LJ70 with 2L-T and we're both running similar setup and boost.

All of Toyota's diesel and gasoline pistons I've seen have significant differences between the turbo and normally aspirated version engines. Maybe the differences between the 2LTE and 3L are not as significant though. Similar to the early 1HZ pistons taking boost well. Admittedly I'm going by pictures I've seen of the 3L pistons as I have not had one in hand. I do have a set of 2LTE pistons on a shelf at home though, and they are quite impressive. From my memory of the 3L pistons, they appear to be cast, where the 2LTE ones are forged.

What I was getting at, is the power advantage to a 3L swap is probably not worth all the work if his 2LTE is still running fine. 17% displacement is not much difference. Everything else except for the camshaft will be the same between the two engines (in terms of power potential). Same fuel system, same turbo, same valve size, etc. I was suggesting that he tune his 2LTE first as there is a lot of untapped potential in his setup.

You have me curious about 3L pistons though. I'm going to look for some high res pictures of OEM ones. I'll point out the differences I had noticed in the past. Not that it's a big deal; just neat to learn.

 

[malteser]

All of Toyota's diesel and gasoline pistons I've seen have significant differences between the turbo and normally aspirated version engines. Maybe the differences between the 2LTE and 3L are not as significant though. Similar to the early 1HZ pistons taking boost well. Admittedly I'm going by pictures I've seen of the 3L pistons as I have not had one in hand. I do have a set of 2LTE pistons on a shelf at home though, and they are quite impressive. From my memory of the 3L pistons, they appear to be cast, where the 2LTE ones are forged.

What I was getting at, is the power advantage to a 3L swap is probably not worth all the work if his 2LTE is still running fine. 17% displacement is not much difference. Everything else except for the camshaft will be the same between the two engines (in terms of power potential). Same fuel system, same turbo, same valve size, etc. I was suggesting that he tune his 2LTE first as there is a lot of untapped potential in his setup.

You have me curious about 3L pistons though. I'm going to look for some high res pictures of OEM ones. I'll point out the differences I had noticed in the past. Not that it's a big deal; just neat to learn.

Yes and I agree with you. If I was in his situation I'd take your advice and improve my engine, since as you say there isn't much difference between the two.

Maybe it was an improvement on the 2LTE then cos the ones I've seen were off a 2LT and they were definately not forged since they had cast lines on the underside, just like the 3L ones.

 

[GTSSportCoupe]

OK, this is a little bit of a tangent, but to satisfy my own curiosity, I looked for pictures of genuine 2LTE and 3L pistons to see what the differences were. Honestly they both look forged to me. A couple major differences I note however are the 2LTE piston crown has an internal oil cooling passage (looking at mine it goes all the way around the inside of the piston crown). In the pictures you can see a hole in the piston that the block oil squirter fires oil into. The 3L piston does not have this. Also, the 2LTE top ring reinforcement layer appears thicker than the 3L. I did read an SAE note by Toyota on the 2LTE development, and I believe I read that the piston reinforcement layer is a ceramic fiber reinforced alloy. Both the piston crown cooling and thicker reinforced ring land are advantageous for turbo application (more heat and higher pressure).

The pistons I have at home also have a special coating on the skirt that these pistons do not have. So it could be the original pistons are different than the ones Toyota is selling now.

They both appear to be very strong pistons though, and I don't think I've ever heard of a 3L piston failing.

Here are the 2LTE piston pictures:

Here are the 3L piston pictures:

 

[malteser]

Those do infact look forged. Maybe there were different variations through out the years and these were the final improved designs?

Anyway, getting back to original post, I'd follow GTSSportCoupe suggestions and improve on the 2L-T since they're essentially the same engine, and if there is nothing wrong with yours I wouldn't justify a swap to a 3L.

 

[GTSSportCoupe]

A final point to the original poster. The 3L block does not have the crank trigger and other sensor needs of the 2LTE ECU. So if you went to a 3L, you'd have to go with a mechanical injection system. If you have an automatic transmission, this becomes tricky, because the 2LTE ECU controls the automatic. So your best bet with a 3L turbo install would be switching to a manual R151F transmission from a LJ78. This will raise the price of the whole project substantially.

 

[LeonLJ78]

thanks for the replies on the 3L, going to your post about ticking the boost sensors. are you able to give me a little more info about the air bleed you have installed and how its installed?

 

[GTSSportCoupe]

thanks for the replies on the 3L, going to your post about ticking the boost sensors. are you able to give me a little more info about the air bleed you have installed and how its installed?

The idea is to 'T' in an air bleed valve right before the ECU MAP (boost) sensor. It must be after the little filter / one way valve things that are on the existing boost hose. It needs to 'T' into this line; don't put it 'in line' as that won't work. The idea is it allows you to adjust how much boost the ECU MAP sensor reads by bleeding off some of the pressure in a controlled format.

The valve that you show above is along the right lines. The one I'm using was given to me by the fellow that came up with this method, and it's no longer available. I did buy a cheap Chinese one to prove a solution for other people, but have not actually tried it yet. This is the chinese one I bought if I remember correct: Pneumatic Flow Speed Control Valve ASC-08 One Way Two Position G1/4" 711811398940 | eBay

I'll try to give that one a go before too long. I can count how many turns I set it at also as a baseline for others.