TD42 Turbo Conversion Project

[ChristoSlang]

If it was a simple as changing the radiator it would not have been one of the biggest topics on a TD42.

I can attest to this.

My Patrol kept on getting hot on the highway, even with an aftermarket radiator. Fueling was set for safe EGT with minimum smoke, timing was spot-on, turbo and downpipe has heat insulation, etc.

The mod that eventually fixed this was to move the intercooler off the top of the engine so that it could breathe cold air. This made a huge difference, even though I resisted Michael's advice for a long time.

Michael also fitted an oil cooler at a later stage, but that did not further lower the coolant temperatures which now run at 75 C for normal use. I have to REALLY murder the Patrol to get it up to 100 C, and I need a very hot day, aircon on and a many kilometers of uphill to get it there.

[jakeslouw]

I was going to ask about better intercooling, but decided against that as I haven't comprehensively played with it.

I've never owned a top-mount intercooler vehicle. But I've never heard of one working well.

[Unkredible]

Jakes, My top mount works well.... :-) You can test it at Afrika Brew...

[jakeslouw]

Jakes, My top mount works well.... :-) You can test it at Afrika Brew...

All lies, Bruce, we know you can't afford the diesel to Hazeldean...........

[Michael]

Wow.......what a nightmare of the last 3 weeks. Been so hectic the last couple of weeks I just did not have time to take photos and update this thread.
Anyways, lets continue. So finally we can start working on the fun stuff........ The turbo and things that make power!!
Have a look at this sext thing, it really is a work of art and man it performs
For those really interested, the turbo specs are as follow:
Arashi TD05 18G with a 6+6 billet compressor wheel and a 9 blade shaft. Im running a 6cm turbine housing as this gives the best overall performance.
We will be boosting around 1,1 - 1,2 bar on this setup with the AFR's running between 20:1 - 22:1 under load.

[Michael]

Ok some more progress info and photos.
The turbo was installed and I fabricated the intake pipe to the air box so that we could start moving the vehicle around. I made a temporary downpipe just so that I can move the vehicle to Viper for the custom 3" exhaust system. The intercooler is also not yet installed, so I just gave it a straight pipe from turbo to intake just to drive the Patrol to Viper and back.
At this stage, the injector pump was still in stock NA state (except for the corrected static timing), so I just opened up the fuel a bit to drive more comfortably.

[Michael]

The injector pump is probably the one item that makes the biggest difference on the build. You can have the best of everything and spend heaps of cash on hardware, but if the pump is not in good condition and tuned correctly, you will feel like everything was a waste of money.
In the diesel world Fuel = Power
But....... more fuel = a richer AFR
So....... add more air (forced induction) to lean out the AFR's and now you have the same AFR's (actually slightly leaner at coasting) as the stock NA setup, but with way more power.

Now this is where the injector pump plays the biggest role. You need the right amount of fuel, at the right time, for the right injection duration to make the fuel burn efficiently. Nissan and Zexel sorted out the pump lift and duration for us, so all we need to make sure of is the fuel quantity and the correct timing.
By just opening up the fuel on the stock pump will give you more power yes....... but you don't want more fuel everywhere in the rev range as this will cause loads of smoke where the turbo is not yet producing boost. You want less fuel between 1,000 rpm and start adding fuel around 1,500 rpm as the turbo starts producing boost.
This is what the boost compensator is for. Its a mechanical system installed on the pump that pushes down a fuel pin as the boost comes in. The rate of increase of fuel can be changed with the spring tension to achieve the desired fuel at the desired rpm.

The thing most people don't know is that you need fuel to produce boost on a diesel engine. You can install a turbo on a NA engine and disconnect the wastegate from the turbo and you will not see 0.5 bar of boost because there is just not enough fuel to drive the turbine....... everything needs to work together.

[Michael]

Madman!!
I don't need to explain why this is necessary on a TD42 or any diesel vehicle that has been tuned but will mention it anyway.
The Madman unit gives you a window to the inside of the engine which you could never see before.
You can now see the EGT's (exhaust gas temperature) which shows you how rich or lean your engine is running and this is key for me to do the tuning. I like to have the EGT's peak around 650 deg pre turbo under load and this will ensure the engine's reliability. If the EGT's go beyond that, I know that my AFR's are too rich and I have to either up the boost or lower the fuel.
If the EGT's really struggle to pass say 500 deg, the AFR's are too low and you will lack the power you need/want.

Some facts of diesel AFR's
A Lean air/fuel mixture = safe for the engine, but you go slow
A rich air/fuel mixture = more heat in the engine, but you go fast
So you need to find the happy place where you still have good power, but with AFR's that are in spec.

Oh yes, and that's where the Madman helps me. It also shows me the condition of the cooling system, water level, oil pressure and much more

[Michael]

Ok, I finally have a chance to wrap up the post. Been so busy this last couple of weeks I can barely keep up with anything.
So lets talk exhaust systems quick. Not too much to say about it besides the standard systems on the TD42 is not much short of useless for a turbo application.
So I have Viper Exhaust build me a 76mm free flow system on every vehicle I do conversions on or power upgrades. Most are installed without any silencer, but for some clients who needs it a bit toned down we install a very small box. Everybody has heard the story of a engine that needs back pressure otherwise something is going to break or burn valves or something....... absolute rubbish!! The easier a diesel engine can get rid of the exhaust gas, the better. You have a significant drop in EGT's and increased performance and efficiency.
On petrol engines you have the same principle, but it gets way more technical on them with exhaust pipe size, scavenging and other stuff which I am not educated enough to say anything about, so let me rather stick to the diesels......

Long story short, this is the system, it sounds amazing and works!!

[Michael]

So the boost system is probably the area where the most time is spent. It really takes a LOT of time as every needs to go exactly where I want it to go. Its like building a puzzle with puzzle pieces that you need to build as well and no picture on the box to show you how it should look. It can be very frustrating as the space is tight in most areas and you need brackets and joints so the pipes have some movement as the engine moves under torque.
I use 57mm tube as we found this to be the sweet spot in pipe size. 63mm also works well, but it is more work to do the pipework and get them through the very tight spots. There is also a barely noticeable increase in boost lag, but both work well.