Boosting 4.2 TD power, candid questions (1 Viewer)

Joined
Jul 30, 2009
Messages
147
I am a ling term owner of my HDJ100 4.2 TD and have been toying with the idea of a mild improvement for a number of years. Lockdown fever has given me some time to consider options and look at the facts. I am not an automotive engineer and would like to get input from ‘those in the know’

1) How the factory set up works
The ECU is mapped from factory but has a number of adjustments built in such as short term fuel trim and long term fuel trim. These allow based on the operating conditions (say outside temperature which influences air density) to adjust fueling to maintain the target Air Fuel Ratio (AFR).
The factory map may be common to all countries and may be set conservatively (e.g. running rich especially at low rpms) to accomdate lower quality fuels (is that correct or a myth ?)
Engines produce peak power when the stochiometric ratio is optimun which for a diesel equals an air to fuel of 14.5:1
Adding fuel without adding air makes the mixture rich but doesn’t increase efficiency. You get marginally more power but produce more smoke and mpg goes down. Rich is safe for an engine perspective bit wasteful on fuel. Reducing richness to optimal afr increases power assuming the fuel is good enough to avoid potentially damaging lean situation.

2) what to do ?
Turbocharging is interesting in the sense that adding boost allows more air into the engine, enabling extra fuel and assuming you hit optimal afr then you create more power.

Staying within the limits of the stock set-up (injectors and turbo), it seems the most effective idea is a waste gate adjustment or a boost controller. Both would allow to increase the max boost provided by the turbo which in turn will provide more air to the engine when it is fully spooled up. There are limitations to the stock turbo (see graph)

But it seems that boosting rpm by 20% sort of still is within the reasonnable efficency point. That will however only work at top end boost. To affect the low end one may want to modify the turbo (different intake turbine to spool up faster etc).
However, on the exhaust side, running higher pressure will lead to increased temperatures. The stock turbo downpipe is an interesting point here because it acts as a bottle neck and also includes the catalyst which tend to suffer from heat which exceeds design paramters.

Replacing the downpipe for a wider diameter (from stock 2.5’ to 3’) and using sport cats which offer less flow resistance seems to be the correct way to avoid excessive exhaust gas temperatures.

So increasing boost by modifying the wategate (stiffer spring or boost controller) and avoiding excessive heat buildup through new downpipe looks like a cheap and effective way to probably pick up 10-20% extra power within the limits of the stock system.
Better intercooler can be added to add cooler / denser air and obviously bigger turbo but then you need to upgrade injectors and at that point the stock ECU is also running out of adjustment headroom. At that point, you probably need a full motec set up etc... not my objective

3) Piggy back units
For years I have been fascinated by these units like unichips. There are tons of dyno graphs and you tube videos.
Fundamentally I see how such unit can alter ecu signals to adjust fueling given various circumstances. But as long as no extra air is provided, i am not sure how much real effectiveness there is. What I can see is:
- they take out excess richness at low rpms which gives more power (and better mpg)
- they add more fuel which gives slightly more power but at less optimal AFR so efficiency goes down. Black smoke isn’t my cup of tea
- they can fuel to full throttle when you are only using part throttle giving the impression of more power
- they can be used to adapt the factory ecu to run a non stock set up (eg bigger turbo, intercooler etc).

While the piggy back will modify stock ecu instructions to the injectors, it will not affect the read the stock ecu makes from the lambda sond (I think, may be I am wrong). So the ECU may want to correct what it will perceive as overfuelling. So the piggy back unit will need to be set up so it can counteract that on a dynamic basis otherwise one gradually comes back to the previous situation.
Note: that may not necessarily be true in all cases as i understand that in wide open throttle position, the ecu may stop checking paramters. But we are not flat out all the time.

Where I stand ?
For a mild improvement, I think I will go for downpipe and wastegate mod. This is a low cost solution (less then 100gbp if diy and removing cats, more expensive if sport cats are used) I can understand how it works and stock ECU should be able to manage. Essentially that means that every day will be a nice cold day where the air is denser so more is available for combustion.

Adding a unichip is definitvely a different spend. The units can be bought for diy install but retail at 1000 gbp and you rely on the default map. Given the above, I see how this could correct some excess richness but then you will simply dumping more fuel. So you get into the diminishing returns and lower efficency / mpg
You need to find a unichip tuner to adapt the mapping to your own engine and with the car in france where I can’t find unichip dealers that is not practical.

Would like to hear the view from the TD experts on the forum.

D79068A8-7431-4938-95BB-FBF72F679E1A.png
 
Joined
Dec 22, 2015
Messages
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Location
Whitefish/Bozeman, MT
You might want to post this in the Diesel Tech section of the forum, you’ll get a lot more input there. One thing to remember is that in many ways turbo diesels are the opposite of turbo petrol engines: when you increase fuel without adding boost in a diesel (richer mixture) it produces more heat and is potentially damaging to the engine. Decreasing fuel or adding boost (leaner mixture) makes it run cooler and is safer and more efficient.
 
Joined
Dec 11, 2018
Messages
233
Location
EU
You can get a Unichip + the software for much less than 1000GBP.

If you have a pre-facelift (4 speed auto) you have the CT26 turbo, same as the 80 and the Australian 100s. Facelift and after, it's a Garret VNT (gt2359v) turbo.
3" exhaust gives noticeable improvement in car response and turbo spool time with no other mods needed and is 100% required if you start adding power in other ways. The FTE is really chocked by the stock exhaust.
The stock intercooler is barely enough for stock power. Again, replacing it is a must, when you start chasing numbers.

The performance market for the Land Cruiser 100 is almost non existent and unfortunately a big chunk of it is in the UK, which sucks due to Brexit.
I got this exhaust - Land Cruiser HDJ100 3" Heavy Duty Full System - Cybox Automotive - https://www.cybox.co.uk/product/hdj100-3-heavy-duty-full-system/ it is well made, it has a large straight through resonator, but they do not offer a cat option for it. I am chasing one aftermarket to add to the exhaust.
For intercoolers this one is very well made and is bolt on - Toyota Land Cruiser 100 Series 4.2 intercooler - AlliSport - https://www.allisport.com/shop/performance-products/intercoolers/toyota-land-cruiser-100-series-intercooler/

The factory ECU cuts fuel when boost starts to increase. I haven't been able to find exact numbers for the VNT turbos, but in Australia the CT26 tops at 12-13psi from the factory and the ECU starts cutting fuel at 15-16psi. There are boost clamps that "hide" the boost from the ECU, but then it does not add the needed additional fuel and increasing boost without increasing fuel can end very bad for the engine. So a piggyback is required for any meaningful results.

Wink 4x4 - Engineered Performance - http://www.wink4x4.com in the Netherlands is a distributor and tuner for Unichip. He also tunes turbos specifically for cruiser - there is a custom CT26 based one he developed for the 1HD-FT on the 80, which should be a more or less bolt on for the FTE. he high-flowed my VNT and fitted better CHRA and compressor wheel. I highly recommend chatting with him, but be advised that he is horrible at communication - can take him a while to respond even if you just paid and wait for him to ship back.
Unichip ECU Mapping Chip Distributor | Unichip Europe - https://www.unichipeurope.com also offers it, but in the UK.
Steinbauer is available in Europe, but if you have an auto, better stay away - it does not cut torque on gear shifts, which eventually wrecks the auto.

Depending on the mileage of the car, the fuel pump gradually starts delivering less and less fuel. Mine was delivering ~80% at 430 000km. These pumps are super rare and expensive to work on, as there are few specialist and diesel benches that know them. In all of Europe I found 1 place in France, 1 in Spain and 2 in UK. Might be more, but well hidden. Refurbishment prices are ~€1500-2000
 
Joined
Dec 6, 2016
Messages
310
Location
Brisbane, Australia
I am a ling term owner of my HDJ100 4.2 TD and have been toying with the idea of a mild improvement for a number of years. Lockdown fever has given me some time to consider options and look at the facts. I am not an automotive engineer and would like to get input from ‘those in the know’

1) How the factory set up works
The ECU is mapped from factory but has a number of adjustments built in such as short term fuel trim and long term fuel trim. These allow based on the operating conditions (say outside temperature which influences air density) to adjust fueling to maintain the target Air Fuel Ratio (AFR).
The factory map may be common to all countries and may be set conservatively (e.g. running rich especially at low rpms) to accomdate lower quality fuels (is that correct or a myth ?)
Engines produce peak power when the stochiometric ratio is optimun which for a diesel equals an air to fuel of 14.5:1
Adding fuel without adding air makes the mixture rich but doesn’t increase efficiency. You get marginally more power but produce more smoke and mpg goes down. Rich is safe for an engine perspective bit wasteful on fuel. Reducing richness to optimal afr increases power assuming the fuel is good enough to avoid potentially damaging lean situation.

2) what to do ?
Turbocharging is interesting in the sense that adding boost allows more air into the engine, enabling extra fuel and assuming you hit optimal afr then you create more power.

Staying within the limits of the stock set-up (injectors and turbo), it seems the most effective idea is a waste gate adjustment or a boost controller. Both would allow to increase the max boost provided by the turbo which in turn will provide more air to the engine when it is fully spooled up. There are limitations to the stock turbo (see graph)

But it seems that boosting rpm by 20% sort of still is within the reasonnable efficency point. That will however only work at top end boost. To affect the low end one may want to modify the turbo (different intake turbine to spool up faster etc).
However, on the exhaust side, running higher pressure will lead to increased temperatures. The stock turbo downpipe is an interesting point here because it acts as a bottle neck and also includes the catalyst which tend to suffer from heat which exceeds design paramters.

Replacing the downpipe for a wider diameter (from stock 2.5’ to 3’) and using sport cats which offer less flow resistance seems to be the correct way to avoid excessive exhaust gas temperatures.

So increasing boost by modifying the wategate (stiffer spring or boost controller) and avoiding excessive heat buildup through new downpipe looks like a cheap and effective way to probably pick up 10-20% extra power within the limits of the stock system.
Better intercooler can be added to add cooler / denser air and obviously bigger turbo but then you need to upgrade injectors and at that point the stock ECU is also running out of adjustment headroom. At that point, you probably need a full motec set up etc... not my objective

3) Piggy back units
For years I have been fascinated by these units like unichips. There are tons of dyno graphs and you tube videos.
Fundamentally I see how such unit can alter ecu signals to adjust fueling given various circumstances. But as long as no extra air is provided, i am not sure how much real effectiveness there is. What I can see is:
- they take out excess richness at low rpms which gives more power (and better mpg)
- they add more fuel which gives slightly more power but at less optimal AFR so efficiency goes down. Black smoke isn’t my cup of tea
- they can fuel to full throttle when you are only using part throttle giving the impression of more power
- they can be used to adapt the factory ecu to run a non stock set up (eg bigger turbo, intercooler etc).

While the piggy back will modify stock ecu instructions to the injectors, it will not affect the read the stock ecu makes from the lambda sond (I think, may be I am wrong). So the ECU may want to correct what it will perceive as overfuelling. So the piggy back unit will need to be set up so it can counteract that on a dynamic basis otherwise one gradually comes back to the previous situation.
Note: that may not necessarily be true in all cases as i understand that in wide open throttle position, the ecu may stop checking paramters. But we are not flat out all the time.

Where I stand ?
For a mild improvement, I think I will go for downpipe and wastegate mod. This is a low cost solution (less then 100gbp if diy and removing cats, more expensive if sport cats are used) I can understand how it works and stock ECU should be able to manage. Essentially that means that every day will be a nice cold day where the air is denser so more is available for combustion.

Adding a unichip is definitvely a different spend. The units can be bought for diy install but retail at 1000 gbp and you rely on the default map. Given the above, I see how this could correct some excess richness but then you will simply dumping more fuel. So you get into the diminishing returns and lower efficency / mpg
You need to find a unichip tuner to adapt the mapping to your own engine and with the car in france where I can’t find unichip dealers that is not practical.

Would like to hear the view from the TD experts on the forum.

View attachment 2576108

@Moridinbg from Bulgaria always provides thoughtful inputs and knows his way around 1HD-FTE. Also, if you have not seen his long rebuild thread, it definitely is a story worth following:

HDJ100 - Body off renovation, now with a hot dip galvanised frame *Picture Heavy* - https://forum.ih8mud.com/threads/hdj100-body-off-renovation-now-with-a-hot-dip-galvanised-frame-picture-heavy.1220814/page-3#post-13419235

In Australia we have such an abundance of diesel workshops and specialist expertise that I am too lazy to do my own engine work and too conservative to make modifications, even though it is a popular activity and the 1HD-FTE is a revered engine here.

If not already known to you, the following additional sources of discussion and information may be helpful places to post your inquiries:

Welcome to Land Cruiser Owners On Line (LCOOL) - https://www.lcool.org (Australian forum – requires registration but is free)

Facebook Groups - https://www.facebook.com/groups/1745801785659911/ (requires registration to join the Group)

Facebook Groups - https://www.facebook.com/groups/154276451369960/ (requires registration to join the Group)
 
Joined
Jul 30, 2009
Messages
147
Thank you bothbfor your comments.
The truck is a 98 so 4 speed and ct 26. It has 165 k miles on the clock.

Re: exhaust I really want a version that retains the cats. French Emission testing is becoming strict and just full decat may not pass. I did an internet search and couldn’t find any supplier. I guess will end up custom made.

Morid, where did you see a unichip for significantly less than 1000gbp ? This is the price Shown on unichip europe website.
Also any thought on the diy version without custom tuning ?
 
Joined
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Messages
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Cluj-Napoca
not to hijack this thread, but linked to the discussion of turbos:

I started to hear a whine when I pass over 1500-1600 rpm on 2002 4,2 diesel...If I lower the revs to 1400rpm, the whine is gone, if I go over 1500 rpm the whine comes back.

It is not loud, but I hear it while driving, so it is annoying (potentially expensive to fix if left unattended)...So my questions goes:

what rpm does the turbo kick in on our diesels?

It is a 150 k km (less than 100k mls) car with only one owner, always serviced at the main dealer.
 
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Messages
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not to hijack this thread, but linked to the discussion of turbos:

I started to hear a whine when I pass over 1500-1600 rpm on 2002 4,2 diesel...If I lower the revs to 1400rpm, the whine is gone, if I go over 1500 rpm the whine comes back.

It is not loud, but I hear it while driving, so it is annoying (potentially expensive to fix if left unattended)...So my questions goes:

what rpm does the turbo kick in on our diesels?

It is a 150 k km (less than 100k mls) car with only one owner, always serviced at the main dealer.
Are you sure its the turbo and not a pulley or a bearing (alternator or something)?
It could also be a (boost) leak somewhere, there are a lot of hoses and gaskets till the air gets from the compressor to the cylinder head.
 
Joined
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9
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New South Wales, Australia
not to hijack this thread, but linked to the discussion of turbos:

I started to hear a whine when I pass over 1500-1600 rpm on 2002 4,2 diesel...If I lower the revs to 1400rpm, the whine is gone, if I go over 1500 rpm the whine comes back.

It is not loud, but I hear it while driving, so it is annoying (potentially expensive to fix if left unattended)...So my questions goes:

what rpm does the turbo kick in on our diesels?

It is a 150 k km (less than 100k mls) car with only one owner, always serviced at the main dealer.

Check your intake manifold nuts aren't loose.
 

ramangain

Clarksonian disciple
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Compressor maps! Whoohoo! I haven't dealt with those for almost 20 years (when I was a VAG 1.8T 20V fanboy, seeing as 5V heads have taken over the world :rofl:)
 
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Are you sure its the turbo and not a pulley or a bearing (alternator or something)?
It could also be a (boost) leak somewhere, there are a lot of hoses and gaskets till the air gets from the compressor to the cylinder head.

Not sure at all in fact...I am very inexperienced in auto-repairs - I mean I can follow an instruction from a forum like I did when replacing the AHC fluid - many thanks for help and info on that by the way!
Check your intake manifold nuts aren't loose.

I will search this forum hoping there is a guide I can use intake manifold nuts (no idea where they are at the moment :) )
This post gave me PTSD (remembering when I had to replace the intake gaskets & how f&#ing hard it is to get to it:D)

I hope you did make pictures and posted them here somewhere, right? :)
 
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Unfortunatelly I didn't make a writeup or a video. But used the 1HD-FTE engine repair/service manual (mostly to get the torque values for the bolts and to know what are the non reusable parts) and this video series as a guide:

Thank you once again for yet another piece of useful information!!!

So the intake manifold nuts are the ones he talks about at minute 22? - He mentioned they were loose. Is this a common problem on our engines?
 
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Thank you once again for yet another piece of useful information!!!

So the intake manifold nuts are the ones he talks about at minute 22? - He mentioned they were loose. Is this a common problem on our engines?

Yes, that's what he is talking about. Mines weren't loose. I've never heard about it being a common thing. I guess it depends if the previous mechanic has installed and torqued them correctly or not.
 
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Yes, that's what he is talking about. Mines weren't loose. I've never heard about it being a common thing. I guess it depends if the previous mechanic has installed and torqued them correctly or not.
Before I jump in there and break something - can these nuts be checked / retorqued without all the actions in video you posted (I mean the action pre-22' minute)? Are they accessible easily?

I must look for service manual, I think I downloaded it at some point....
 
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Before I jump in there and break something - can these nuts be checked / retorqued without all the actions in video you posted (I mean the action pre-22' minute)? Are they accessible easily?

I must look for service manual, I think I downloaded it at some point....

Some might be accessible, but I think some will be blocked by the injection pipes.

The process of removing and reinstalling everything is well detailed in the manual (except for the torque values of the viscous heater mounting bolts)
 
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