2LTE tune-up (intercooler & high-flow turbo)

[Peter P]

After driving the truck some more I have to say the new turbo really is rather good! I'm not sure if the ECU has adjusted or the turbo is running in but the low RPM performance really has made the truck a lot more fun to drive. The lacklustre performance at low revs and terribly slow turbo spool have always been the problems I'd assumed would be the most difficult to address with this engine so this is a very welcome improvement. It's actually viable puttering up the windy, hilly roads where I live in third gear under 2000rpm now. I'm seeing 10PSI by 2100rpm which is also a definite improvement. And this is with just with factory fueling so I'm starting to think this might all end up in a better place than I had anticipated Really quite encouraging to see how much this engine has been improved without adding any fuel. The gains from the 2.5inch exhaust, intercooler and improved turbo have stacked up quite nicely.

 

[Peter P]

I finally managed to get hold of the correct Chelic speed controller and have been playing around with some basic tuning so figured it was time for another post. I couldn't find anywhere online to purchase these but in the end Chelic were kind enough to build 5 to order. I have teed the speed controller into the line between the MAP sensor and the little filter that precedes it and it works brilliantly.

It seems the ECU starts cutting fuel gradually from 10PSI in an effort to prevent boost from reaching 14.5PSI at which point the ECL light comes on and fuel is cut more drastically. The initial fuel cut can definitely be felt as a loss of power above 10PSI even before the ECL comes on. So I reasoned there was a potential benefit to using one of these to trick the ECU into thinking there is less boost that there really is even if I'm not running in excess of 14.5 PSI and I don't need it to avoid the ECL and hard fuel cut.

This morning I tapped a wire into the line from the MAP sensor before it plugs into the ECU and used a multimeter to get some voltage readings. Seems the general consensus is that 10PSI should correspond to 4.0V however my numbers were a bit different. I had 3.5V at 10PSI and 4.2V at 14PSI. I have the Chelic bleeding enough boost that the readings are now 3.0V at 10PSI and 3.6V at 14PSI. So effectively the ECU is probably seeing 10-11PSI max and this definitely gives better and more consistent power right up to the current max boost of approx. 14PSI. I think there is a bit of a trade-off involved however. Bleed too much off and power is lost at low boost, bleed too little off and power is lost at high boost.

I have also tried various settings of the fuel screw. 1/4 of a turn gave a good bump in power, 1/2 a turn felt amazing but the engine started threatening to runaway and it mucked up engine braking so I've ended up somewhere between 1/4 and 3/8 of a turn. I'm not quite sure how others have managed 3/4 of a turn seemingly without issue. Obviously this method of increasing fuel is crude, but it definitely works and in conjunction with the speed controller the results are surprisingly good.

It would be great if someone could figure out a way of increasing fuel under throttle only without having to use a chip! $2500 for Unichip here in NZ

In hindsight I should have opted for a TD04 or other more modern turbo (as others advised ) as while the new turbo definitely performs better than the original CT20, it does still take a bit long to spool which means it's hard to make good power in the low RPMs. Nonetheless, the improvement from stock with all the changes I've made is very, very good.

 

[GTSSportCoupe]

Great work!

You can have some more fine tuning ability of fuel by tapping a 2.5k Ohm potentiometer in place of the fuel correction resistor on the side of the injection pump. Measure the one on the pump as a baseline. I cut the wires at the ECU, and wired in there.

You're right the boost bleed does loose fuel lower in the curve, just giving top end power. But by increasing the spill control valve, you have corrected for that, and still gain in the top.

As to why the number of turns is different for different people. It's a mechanical thing, and is there to fine tune the pump settings. It'll be different for each pump. In my case, for both my old and new pumps, 3/4 turn was the ticket.

Thanks for sharing your experiences, and the different voltages.

I design electronics for a living, and have been meaning to setup a 30psi MAP sensor with configurable output. This could allow more accurate tuning for the 2LTE ECU than the bleed valve. Basically you'd set it for the max boost you plan to run, and it would produce a normal factory looking 0-10psi fuel compensation curve to the ECU.

I find my bleed valve works great for a few months, and then I need to re-tune again. Not sure why; maybe debris gets past the filter and clogs the air passage in the bleed valve a bit? It is crude and a PITA.

 

[Miloslavich]

Nice clean fab work. Looks excellent

 

[Iamkeenas]

Mate looking like good progress!!
Been meaning to add some photos of my set up as well 2lte
Intake piping jrp 14n1 guage
Wired in potentiometer which seems to help with quicker spool up times with lower revs.
White switches are for winch

 

[Peter P]

That's great to know regards the potentiometer folks

I might have got to that already had I not been dealing with another round of failed cylinder head drama The problems started right after the turbo swap. When that job was done I went back to an 88oC thermostat, but the housing didn't seal properly after it was put back together, I think due to some corrosion on the surface that mates up to the rubber seal. I took the truck on a long road trip more or less the next day (bad idea probably) and it dropped just shy of a litre of coolant. I only realised when we arrived and I noticed the coolant temp notch up a couple of degrees when I pulled up. The viscous fan had locked up a lot but because it was also the first big trip since I got the intercooler running, I put it down to the IC radiator dumping extra heat on to the fan hub. I fixed up the corrosion and got a proper seal for the trip home and things seemed ok.

Next trip the fan got a bit eager again and this time I was immediately suspicious, popped the hood and the overflow tank had shed coolant all over the show.

Anyway, this time I am going with an OEM head for certain! Not sure if the previous one failed (other that it being a s*** design already) due to having air in the cooling system or because it was an aftermarket head of inferior quality or both (also had rough starting problems ever since it was installed) but it only lasted 40,000kms. For the majority of those kms the cooling system has been WAY better than stock and I've never run post turbo EGTs above 1000F so as you can probably imagine it was a bit of a bugger to have this happen again. The new head will be this truck's fourth and it hasn't even hit 200,000kms.

I figured, in for a penny in for a pound so hunted around and found replacement hoses for the entire cooling system, cleaned up all the rust on the metal coolant pipes and repainted these and the valve cover while I was at it. This truck certainly ought now to be set up extremely well to avoid another premature failure!! I should have it back in the next few days...

 

[Peter P]

Iamkeenas - Certainly no unnecessary piping in that WTA setup! A good idea there

GTS - If you ever get around to employing your configurable MAP sensor idea, I might be keen to get one off you!

 

[GTSSportCoupe]

That's great to know regards the potentiometer folks

I might have got to that already had I not been dealing with another round of failed cylinder head drama The problems started right after the turbo swap. When that job was done I went back to an 88oC thermostat, but the housing didn't seal properly after it was put back together, I think due to some corrosion on the surface that mates up to the rubber seal. I took the truck on a long road trip more or less the next day (bad idea probably) and it dropped just shy of a litre of coolant. I only realised when we arrived and I noticed the coolant temp notch up a couple of degrees when I pulled up. The viscous fan had locked up a lot but because it was also the first big trip since I got the intercooler running, I put it down to the IC radiator dumping extra heat on to the fan hub. I fixed up the corrosion and got a proper seal for the trip home and things seemed ok.

Next trip the fan got a bit eager again and this time I was immediately suspicious, popped the hood and the overflow tank had shed coolant all over the show.

Anyway, this time I am going with an OEM head for certain! Not sure if the previous one failed (other that it being a s*** design already) due to having air in the cooling system or because it was an aftermarket head of inferior quality or both (also had rough starting problems ever since it was installed) but it only lasted 40,000kms. For the majority of those kms the cooling system has been WAY better than stock and I've never run post turbo EGTs above 1000F so as you can probably imagine it was a bit of a bugger to have this happen again. The new head will be this truck's fourth and it hasn't even hit 200,000kms.

I figured, in for a penny in for a pound so hunted around and found replacement hoses for the entire cooling system, cleaned up all the rust on the metal coolant pipes and repainted these and the valve cover while I was at it. This truck certainly ought now to be set up extremely well to avoid another premature failure!! I should have it back in the next few days...

Sorry to hear about the grief with the cylinder head. Maybe consider using Evans Waterless Coolant to keep it from stressing the head? I've put about 100,000km on mine (OEM Toyota newer generation head) with Evans coolant only. I have not been kind to it, and so far no problems.

This happens pretty much every long trip at some point when I'm towing in 35C summer here year after year. Note temp gauge! On this particular trip, I drove it for 3 hours this way (t-stat had partially failed). It can be hard on the engine oil, but otherwise it keeps ticking, haha.

 

[bj70bc]

Sorry to hear about the grief with the cylinder head. Maybe consider using Evans Waterless Coolant to keep it from stressing the head? I've put about 100,000km on mine with Evans coolant only.

This happens pretty much every long trip at some point when I'm towing in 35C summer here year after year. So far so good! Note temp gauge! On this particular trip, I drove it for 3 hours this way (t-state had partially failed). It can be hard on the engine oil, but otherwise it keeps ticking, haha.

View attachment 3448902

holy christ balls! thats damn nuclear on an oem gauge
scary

 

[GTSSportCoupe]

holy christ balls! thats damn nuclear on an oem gauge
scary

It sucks indeed. I hit that pretty much every summer when towing up the worst hills. Yet the truck keeps going. Evans coolant does seem to work.

Guy on here called 'Gerg' also from BC ran a turbo 3B towing an 18' trailer every summer in his BJ60. He used Evans too, and was hitting 270F coolant temps regularly. IDI turbos are so bad for dumping heat into coolant. Anyhow, his held up too.

 

[bj70bc]

yes i read ever post from gerg before turboing my 3b, including using the turbo sizing spec'ed out by dougal.
i dont get over 210
but i should prob switch to evans at some point...

 

[Peter P]

Yeah I thought about Evans but $$$ and not being able to top up with water in an emergency are downsides. Honestly with the big custom radiator the cooling is so good it barely ever rises more than 3 or 4 degrees C above the thermostat opening temp even with sustained 1000F EGTs prior to the intercooler. I've not seen anything above 91C aside from when there was air in the system. The way it is setup now, EGTs top out at about 850F which is probably at least 300 lower than stock. When I bought the vehicle I would see 110C coolant temps up big hills. If the cooling I get now isn't ROCK SOLID, I don't know what is! I think I just screwed up by driving it for hours with air in the system.

I'm thinking I might go back to the 82C thermostat as an extra preventative measure anyway. I only used the 88C again because I though it might help with fuel economy but honestly, I'm not sure it even makes a difference. Is there a consensus on whether a lower temp thermostat helps in terms of prolonging the head?

I think the lessons here are 1. don't go with an aftermarket cylinder head and 2. you can't run these engines low on coolant even if the coolant temperature is still cool. They just won't tolerate it. On the other hand, maybe I just got a dud.

The fact that you can run those temps with Evans and it's been good as gold would seem to confirm it's not actually the overall temperature itself that is the issue, rather hot spots from boiling coolant. Air in the system is just an additional invitation for this I guess.

 

[GTSSportCoupe]

yes i read ever post from gerg before turboing my 3b, including using the turbo sizing spec'ed out by dougal.
i dont get over 210
but i should prob switch to evans at some point...

When I'm not towing, that's about as hot as mine gets also. When I tow I'm moving 8000-9000lb total; so definitely tough for the little motor.

Yeah I thought about Evans but $$$ and not being able to top up with water in an emergency are downsides. Honestly with the big custom radiator the cooling is so good it barely ever rises more than 3 or 4 degrees C above the thermostat opening temp even with sustained 1000F EGTs prior to the intercooler. I've not seen anything above 91C aside from when there was air in the system. The way it is setup now, EGTs top out at about 850F which is probably at least 300 lower than stock. When I bought the vehicle I would see 110C coolant temps up big hills. If the cooling I get now isn't ROCK SOLID, I don't know what is! I think I just screwed up by driving it for hours with air in the system.

I'm thinking I might go back to the 82C thermostat as an extra preventative measure anyway. I only used the 88C again because I though it might help with fuel economy but honestly, I'm not sure it even makes a difference. Is there a consensus on whether a lower temp thermostat helps in terms of prolonging the head?

I think the lessons here are 1. don't go with an aftermarket cylinder head and 2. you can't run these engines low on coolant even if the coolant temperature is still cool. They just won't tolerate it. On the other hand, maybe I just got a dud.

The fact that you can run those temps with Evans and it's been good as gold would seem to confirm it's not actually the overall temperature itself that is the issue, rather hot spots from boiling coolant. Air in the system is just an additional invitation for this I guess.

All great points. My theory is the pre-cups shed heat so quickly, that it's likely coolant is boiling locally and making vapor pockets basically any time the motor is under load; even when coolant temps are just fine. I think over time it just stresses the head.

Regarding the 82C t-stat, I used to swap mine to 88C in winters, but don't bother anymore. If you look at the newer 2LTE found in the LN165 etc, they use only the 82C.

I've had air in my system a few times due to various coolant leaks. I drove quite a bit too, and no issues. I wonder if in your case it's more just a bad off shore head. Do you have pictures of the cracks?

I agree about the Evans. It actually sort of sucks, as it doesn't transfer heat as nicely as water, so on average runs quite a bit hotter. But, as you say, it must be doing it's job to keep head temps more even; especially around the pre-cups - by preventing the localized boiling/vapour barriers. Probably if I did not tow, I wouldn't bother with it.

BTW, you can add water to Evans; it just looses it's advantages. I just keep a gallon of Evans in my vehicle at all times for top up. If something bad happens, worst case I just put water in.

Anyhow, I love the work you're doing and your perceptiveness and ideas around these issues. Glad to see you back on the forum.

 

[Peter P]

When I'm not towing, that's about as hot as mine gets also. When I tow I'm moving 8000-9000lb total; so definitely tough for the little motor.



All great points. My theory is the pre-cups shed heat so quickly, that it's likely coolant is boiling locally and making vapor pockets basically any time the motor is under load; even when coolant temps are just fine. I think over time it just stresses the head.

Regarding the 82C t-stat, I used to swap mine to 88C in winters, but don't bother anymore. If you look at the newer 2LTE found in the LN165 etc, they use only the 82C.

I've had air in my system a few times due to various coolant leaks. I drove quite a bit too, and no issues. I wonder if in your case it's more just a bad off shore head. Do you have pictures of the cracks?

I agree about the Evans. It actually sort of sucks, as it doesn't transfer heat as nicely as water, so on average runs quite a bit hotter. But, as you say, it must be doing it's job to keep head temps more even; especially around the pre-cups - by preventing the localized boiling/vapour barriers. Probably if I did not tow, I wouldn't bother with it.

BTW, you can add water to Evans; it just looses it's advantages. I just keep a gallon of Evans in my vehicle at all times for top up. If something bad happens, worst case I just put water in.

Anyhow, I love the work you're doing and your perceptiveness and ideas around these issues. Glad to see you back on the forum.

Thanks mate It's addictive stuff. There's some kind of perverse enjoyment that comes from taking something everyone says is s*** and trying to turn it into something half way decent. That said, if this happens again I'll probably have to reconsider that idea

Cripes... don't say that! There must be a threshold in terms of both EGTs and coolant temps below which ZERO boiling is taking place but I guess we'll never know where that is exactly.

Righto... back to the 82C t-stat it is. That's encouraging to hear regards the running when low on coolant. Good to know re Evans too.

I'll try to post some photos of the deceased cylinder head