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We are now in our 11th year of trading so you can rely on us to provide the best products at the lowest price backed up with top-notch service. Only a few other tuning companies have been around as long and the majority are resellers and not manufacturers like Tuning Diesels.

We believe in offering products which give a safe and reliable power increase, rather than make optimistic claims and this is one reason why we only quote an approximate percentage increase and it also explains the lack of hype and bull on our websites.
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Our prices are lower because we do not use distributors and other middlemen, and because all design and development is done in-house.
"Please remember that the sellers of higher priced products, although giving a convincing justification for their prices, fail to point out that in reality. It is you who are paying for their development costs and big advertising  and marketing budgets, fancy packaging etc."
Cover common issues affecting the performance of most diesels and also those that reduce the effectiveness of our tuning products. 


A remap involves the reprogramming of your engine ECU via the diagnostic socket under the dash. On most newer diesels, it cannot be done this way, meaning that the ECU has to be removed and opened. Even this method isn't possible on many vehicles and prising open the sealed ECU on a vehicle still under warranty is not a good idea (the ECU is also often secured by anti-tamper bolts that must be drilled out to remove it).

Our Synergy tuning products on the other hand are 100% plug-in (with a few exceptions) so you can fit one yourself and, equally important, remove it for servicing or warranty work if your vehicle needs it and of course transfer it to your next vehicle.

Many remaps have more effect at higher rpm and progressively less at mid to low rpm and so are more attractive to the 'sporty' driver who is used to driving a petrol-engined vehicle. For the majority of our customers, a Synergy is all you need and is nearly always considerably more cost-effective.

ADJUSTABILITY: You can also adjust the performance and have the option of 3 settings selectable while driving if you fit the optional dash switch.

TRANSFERABILITY: Don't forget another important point - our modules can be transferred to your next vehicle at little cost, a remap cannot.
GO FOR IT! The Synergy will enhance and boost the results of any remap. This is because remaps work by increasing the injector opening time, whereas the Synergy increases the fuel pressure so the overall result is even more fuel injected, giving fantastic performance. So if any remapper tells you it's not possible, then we can prove them wrong.

For example: BMW 2L engine in the Rover 75 / Mg ZT*: 115bhp standard, 140bhp with typical remap, 150 with RonBox 2a on max, both (RonBox on setting 1 or 2) 170bhp. Even the crude 160bhp remaps work better with a RonBox 2 fitted.

Similar fantastic results have been seen on the 2 & 2'.2L Mondeo mk3 / X-Type engines, + Mazda's 2L, Citroen C5 2L, Alfa, Fiat, Vauxhall 1.9L 8v engine etc etc. 

All common rail tuning boxes work by raising the fuel pressure at the injectors. If the pressure wasn't increased from the normal level, there would be no power increase either. Below about 3000 rpm, the normal working pressure is below the maximum level which is reached above this rpm so it can be safely raised by the Synergy to this level, thereby giving much better low down and mid-range torque.

Unlike many rival products, we can then limit or even stop the pressure going any higher so your injection system is not put under any additional strain. Clearly if you do not increase the pressure over 3000 rpm above the normal maximum, you will not increase the engine's standard maximum bhp or torque output above 3000 rpm either, so any company claiming big bhp increases and also that the pressure is not raised above the maximum level is pulling the wool over your eyes. You cannot have one without the other.

Please ask for our Synergy 2'E' version if you want the power over about 3000 rpm to remain standard. You will still get the same benefits as our standard models below this rpm, such as reduced turbo lag, less gear changing, easier towing, better in-gear acceleration etc. Some insurers may be agreeable to the 'E' model being fitted as the 0-60mph time and top speed are unchanged.
4) If I change my vehicle can I transfer the module to it? 
In most cases, yes. The cost is £29.95 for recabling and reprogramming, or just £10 if the cable is okay but reprogramming is necessary. 

We can also upgrade some Synergy 1s into 2a or 2b, or convert a 2c or 3C into a 2a or 2b. The only thing we can't do is to convert or recable a VP or PD box into a common rail one.
5) Will tuning the engine affect the dpf? 
Any extra fuel, whether from a tuning box or remap, means there is going to be some additional particulates produced, and thus the dpf will have more work to do and may regenerate (clean itself) more often when you travel at a steady speed of over 40mph. 

In our experience, the impact is minimal provided your driving includes regular motorway/out-of-town driving at a steady speed. Vehicles used only for town driving should be tuned with care - city taxi drivers hate the dreaded dpf more than anyone and there is no solution other than having it removed, which is illegal and an MOT failure. However, dpfs can now be cleaned in situ – please contact dpf-doctor.co.uk.
6) Which vehicles are best for tuning? 
Generally older models without a dpf (pre-2009) and those with a Bosch injection system give the best results. Vehicles with a Siemens or Delphi system won't usually give as large a bhp increase (ie above 3000rpm), though the results below this can be almost as good as a Bosch system.

So if you asked me which used vehicle to choose I would say a pre 2009 Alfa, BMW, Chrysler, Fiat, Hyundai, Jeep, Kia, Mercedes, Renault (not 1.5dci) Saab, Vauxhall, Volvo 2.4d.
Some engines have a fuel pressure limiting valve fitted to the fuel rail or injection pump which prevents the maximum fuel pressure being raised by much so the bhp increase above 3000 rpm is restricted. Examples are: Honda, Mitsubishi, some Nissans, Subaru, Toyotas, some 1.7L Vauxhalls and others with a Denso injection system.
7) Why do you not quote power and torque figures? 
90%+ of drivers never take their vehicle to a dyno so would never know whether our figures were accurate (a point not missed by our competitors who therefore feel safe in quoting unrealistic figures to attract the boy racers).

When we have quoted figures, our rivals have just upped theirs to the same value and added a bit on 'for good measure !

In any case a dyno run takes only about 15 seconds, so the results can be better than would be possible on the road during a sustained full throttle run (most tuning boxes can be set much higher for a dyno run than they can on the road, where they will cause limp mode after 20-30 seconds when set too high). NOT OURS - WE PROGRAM THEM SO ALL SETTINGS CAN BE USED ON AN ENGINE IN GOOD WORKING ORDER, which is why on a dyno ours may seem inferior to some rival products.

We prefer to let our customers judge for themselves, safe in the knowledge that they can return the item within 30 days for a full refund if they aren't satisfied. It's a policy that works for us since refunds amount to barely a handful per year.
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