TD5 TUNING GUIDE

This guide outlines how I approach TD5 tuning, the process, what I won’t do, and the considerations that matter when deciding what the right tune for you is.
 
Who this is for (and who it isn’t)

This guide — and my work generally — is aimed at owners who:

• Plan to keep their vehicle

• Value reliability and drivability over theatrics

• Prefer well-thought-out engineering over rushed results

• Want something developed carefully rather than pushed to extremes

It probably isn’t for you if:

• You’re chasing maximum smoke, noise, or attention

• You want the biggest dyno number available

• You’re looking for the cheapest or fastest solution regardless of consequence

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There’s nothing wrong with those goals — they’re just not mine.
 

What I won’t do
Over the years I’ve worked on many vehicles and turned down jobs where I wasn’t comfortable with either the condition of the engine or the type of tuning being requested. Drawing those lines early avoids problems later.

Boost boxes
ECU pressure recalibration: yes. Boost boxes: no.
The TD5 ECU has a programmed boost pressure limit of around 1.38 bar. This can be raised safely within the ECU software, allowing the engine to retain its safety strategies and ensuring the ECU always knows the true manifold pressure.
Boost boxes sit between the pressure sensor and the ECU and artificially lower the signal. This prevents the ECU from knowing actual boost pressure, disables over-boost protection (for example if the wastegate sticks), and makes accurate mapping impossible. Proper tuning means the ECU always has correct information and retains its safety functions.
 
Excessive smoke
A small amount of smoke off-boost isn’t unusual and, in off-road use, can be part of the fun. What I won’t do is write an excessively smoky map for road use.
Over-fuelling contributes to cylinder bore washing, increased piston ring wear, elevated exhaust gas temperatures, and premature component failure. I run a dual-map setup myself and have a little fun with the second map, but beyond that point the downsides outweigh any perceived benefit.
 
A note on popcorn limiters
I’m not a big fan of popcorn limiters, although I do offer them if requested. They increase exhaust gas temperatures and I remain cautious about their long-term effects, even though many people have run them without obvious issues.
Where they’re used, I prefer they’re done with restraint.
 

The remapping process

In-person remapping
All in-person TD5 remaps begin with an engine health check. This includes fault diagnostics and monitoring key engine parameters to ensure the vehicle is suitable before any changes are made.
Flashing the map itself takes only a few minutes using my specialist software. You’ll then have the opportunity to drive the vehicle and confirm you’re happy with the result.
 
Remote remapping using Nanocom
Using a Nanocom, remote remapping is straightforward. You’ll need to read out your current map, VIN, and Nanocom device ID using your Nancom and SD card, and send these to me by email.
I then modify your existing map based on your vehicle and chosen tuning, and return it for you to flash back onto the ECU. The Nanocom uses an SD card to transfer files between the unit and your computer. A full guide is available on the Nanocom website, and I’m happy to talk you through the process if needed.

 

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Which map is for me?

Stage 1
Stage 1 makes use of the engine’s standard hardware, and is an easy quick win to improve performance over standard. I optimise the fuelling and timing, and the result is a much stronger engine which usually has better economy too.

 

Stage 2 and Stage 2+
Stage 2 and Stage 2+ tuning assumes some supporting hardware changes, typically:

• A larger intercooler (Airtec, Alisport, or Serck — I typically use Airtec)

• EGR removal and cat removal where emissions regulations allow

These changes improve charge air cooling and reduce restriction, allowing the engine to breathe more easily. The aim is improved response and consistent performance rather than chasing extremes.

The Stage 2+ setups produces 449 Nm of torque and 183 hp. More importantly, the delivery is smooth, usable, and well within what I’m comfortable running long-term.
For most owners, this represents more than enough power and can be relied upon day in, day out even for the most demanding applications.
 
Beyond Stage 2+
The TD5 aftermarket is extensive, and there are many possible routes beyond Stage 2+. Rather than listing everything, the sections below cover the most common considerations and where compromises begin to appear.

Turbo selection
With the standard turbo, boost pressure can be increased modestly (typically from around 1.1 bar) to around 1.4 bar. I wouldn’t recommend running a standard turbo much beyond 1.4 bar, as additional pressure tends to generate heat rather than airflow once the turbo moves outside its efficient range.

For higher boost levels, a hybrid turbo or VGT becomes a more sensible option.
Hybrid turbos retain standard casings with higher-flow internals and can support higher pressure ratios, though response depends heavily on specification. VGT turbos improve low-rpm response by adjusting vane position to suit exhaust flow, making a TD5 feel significantly more modern. As always, size selection is a balance between response and peak flow.
I’m happy to advise on turbo choice based on intended use.
 

Notes on common hardware upgrades

Cylinder head upgrades
While 15P heads are generally reliable, engines running larger turbos may benefit from an AMC head and high-tensile head studs to reduce the likelihood of gasket failure. 
Early 10P heads are more prone to cracking around fuel galleries and head gasket failure than later 15P heads. For long term reliability I would recommend considering an AMC head for anything beyond stage 2 on a 10P engine.

Injector nozzles
Standard injectors are sufficient for Stage 1, 2, 2+, and many larger-turbo builds. Larger injector tips are only required at the upper end of aftermarket turbo options.

Exhaust manifold
The factory TD5 manifold is compact but prone to warping, even on standard engines. De-webbing improves reliability, while aftermarket manifolds improve volumetric efficiency where required and if done right tend not to warp.

Exhaust systems
A free-flowing 2.5” exhaust is suitable for most setups, including moderately larger turbos. A 3” system is generally only necessary with the largest turbo options, (however, a 3” rearmost section does sound rather nice!)

MAP sensors
Higher boost applications (>1.5 bar) require an upgraded MAP sensor. I can advise on direct-fit part numbers and supply map calibration to suit.

Silicone boost hoses
Silicone hoses offer improved integrity over ageing factory hoses, which are prone to internal collapse. This can be done for any stage tune and is quick and cheap to do.

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Air filters
The standard airbox and filter are adequate up to and including Stage 2+. Larger aftermarket turbos often require bespoke intake solutions. Performance air filters let you hear the induction noise which can sound nice but I don’t find them necessary on anything up to stage 2+.

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Can I remap my 10P?
Yes — but it requires more work than a 15P.
Because the MSB ECU is not programmable, your options are:

• Fitting a programmable chip to your existing ECU (a service I don’t currently offer)

• Replacing the ECU with a programmable unit, which I do offer, taking your existing ECU in part exchange

A programmable ECU allows future remapping and offers greater flexibility than the original MSB unit.
 

 

A final note
If you’re unsure which route is right for your vehicle, feel free to email me. I reply personally, I’m happy to answer questions, and I’m equally happy to say when something isn’t necessary — or isn’t a good idea.
 

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To see my TD5 remapping options available for purchase, click below.