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Benefits of a Diesel Tuning box over a Remap (tuning chip)

14th May 2009 | Share:

speedometerWe often get posed the question, why should I choose a tuning box over a remap? Isn’t a remap better?

It’s a common statement that remaps are better than tuning boxes, but we believe that is not at all the case. The difference in performance is small and often nothing (especially with the cheaper remaps). There are many features of diesel tuning boxes that are advantageous to having a full ECU remap. These are:

  • As an ECU remap re-writes the manufacturers file on the ECU, it is a permanant upgrade and will void any manufacture warranty. (unless you pay again for another remap to put it back to normal)
  • A diesel tuning box can, in most cases, be fitted and removed very easily and won’t cause any warranty issues. You can have your vehicle back to original in minutes. The inclusion of  an on/off remote with our tuning boxes means the car can be back to original with the touch of a button.
  • An ECU remap gives you one tuning type, its tuned and thats it (this also applies to many of our competitors tuning boxes).
    The Speedhawk boxes come with 9 pre loaded tuning maps to ensure you can get the most efficient results . By getting the most efficient tuning from your engine will result in the most power and the best fuel economy.
  • Good ECU remaps will cost in excess of £500. However even the poorer ECU remaps cost over £300. That remap will only apply to your current car. Change your car and thats another £300 to get it remapped.
    With our tuning boxes, you can move them from one car to the next with minimal or no cost. Sometimes a new harness is needed and sometimes the tuning box may need to be reprogrammed. Often the tuning box can be directly swapped from car to car so your new car is tuned for free. Compared to ECU remapping that is a saving of….£300! (more for the better remaps).
  • Being completely plug and play, our tuning boxes have the added advantage that they cannot be wiped when your car goes in for a service. This cuts out a lot of hassle and saves money if the remapping company charges for every reinstall!

We understand that some people prefer ECU remaps and of course they are also effective, but we believe both remaps and tuning boxes have their place in the market.

Click here to find the right tuning box for your vehicle, or call us on 023 8070 6547 to find out more.


43 Responses to “Benefits of a Diesel Tuning box over a Remap (tuning chip)”

  1. JAMES MASON says:

    I have already had my SAAB 1.9TD upgraded by SAAB, what will happen to this if I bought Speedhawk as the Hurst boosts from 150bhp to 170bhp.

  2. BHP Plus says:

    If the upgrade by Saab was in the ECU, they will be adjusting similar setting that the tuning box will influence. Therefore it is not advisable to use a tuning box as well.

    If you have upgraded the Saab with equipment unrelated to the ECU or injection system (e.g. exhaust, turbo, induction kit etc.) then you can still use the tuning box without any problems.

  3. Brian Quinlan says:

    I have a Renault Megane 1.9 DCi 130 2006 model.
    What benefits will this box provide? will this improve my fuel eco and is it easy to fit? It sounds it.

    oh and how much is it?

  4. BHP Plus says:

    @Brian Quinlan
    The increase on this car is from 130bhp up to around 165bhp. The system is a common rail and depending on your driving style and engine condition, you should see typical MPG improvements of around 10-15%. Although it could be as high as 20%.
    The price of this tuning box is £325. I invite you to use our ‘Find the Tuning Box for my Vehicle’ application guide on our website at to see full details.

  5. Albert Baker says:

    I have a Peugeot Expert 2.0 HDI van, which has 8 valves and is 110 bhp!
    Would it be of benefit to fit one of your units?

  6. BHP Plus says:

    @Albert Baker
    On our site we are listing improvements up to about 136BHP. Also an extra 40 torque. You can see the full details on our site here:

    Peugeot Expert 2.0 HDI 109BHP Tuning

  7. Mr G Siddiqui says:

    Most modern diesel cars (like mine) have diesel particle filters (DPF’s) fitted, and also EGR (Exhaust Gas Recirculation) valves fitted; can you guarantee or at least confirm that your tuning boxes will not cause any damage to these important components. I have heard some horror stories with these failing when diesel cars have been fitted with tuning devices. I hasten to add that none of those involved your company’s product.

  8. BHP Plus says:

    @Mr G Siddiqui
    You are correct that some cheaper and not so advanced tuning boxes can cause problems, especially with DPF’s. However the Speedhawk tuning boxes have been developed in such a way that won’t cause any damage to these components. The great versatility in map programming that we have on our boxes allows us to get the correct characteristics to overcome any issues that can occur with those components.

  9. IAN McLAREN says:


  10. BHP Plus says:

    You’ll be please to know that our tuning boxes do NOT affect the warranty on any car, so feel free to enjoy the performance benefits straightaway.

  11. Mark Redding says:

    I have just taken delivery of a Seat Leon FR 170 BHP. It’s fitted with a common rail fuel injection system.
    As with most of the latest diesel engines, it has a DPF. I would like a little bit more engine performance but not at the detriment of damaging the DPF or invalidating my manufactures warranty.
    Sensibly, would someone please advise what tuning route I should take?

  12. BHP Plus says:

    @Mark Redding
    DPF’s can be tricky with tuning as it can cause them to clog up quickly. Our tuning boxes are designed specifically to operate in a way that won’t affect your DPF. Many cheaper tuning boxes cause problems with the filter.
    Our tuning boxes won’t affect your warranty, unlike a remap.

  13. IAIN AYERS says:


  14. Chris says:

    i have a vectra C 2.0dti 100bhp 2005 model, could you please tell me how much more bhp i will get, i also read that having a tuning box over fuels the car got get the power is that correct?

  15. John Dovies says:

    Tuning boxes in my experience do not come close to the professional install and set up of a solid state ecu remap. DPF are difficult to adapt to an ecu remap at the best of times, how does a tuning box with limited scope on the whole engine do this???
    ECU remap are safer, provide bigger gains when implimented correctly.

  16. BHP Plus says:

    Hi Iain, that BMW is a great engine for tuning boxes and you should see gains to around 263bhp and an extra 80 on your torque.

    Hi Chris, that vehicle is a VP system and should give results up to around 120bhp. It is not correct that a tuning box over fuels a car to get the extra power. One of the aspects it alters is the fuel pressure to result in a more efficient fuel/air mixture. Diesel engines as standard do not use an efficient mix and its this the tuning boxes are exploiting.

    @John Dovies
    Hi John, thank you for your comment. Despite this article, we do not disagree with ECU remaps. We know they have their place in the market. However it is not correct to say that an ECU remap will provide bigger gains than a tuning box. A good ECU remap may provide better gains over a poor tuning box (of which there are many) but the way out boxes work means they will generally give similar results to a remap.
    In terms of DPF, that is probably where our tuning boxes have an advantage over a remap. Again, poor tuning boxes can cause problems with DPF’s (as our old boxes did over a year ago). However the Speedhawk system has smart technology to prevent DPF issues and they work seamlessly with them.
    There is a lot of bad press about tuning boxes generated by ECU remap companies and customers of poor performing and cheap tuning boxes. But a good tuning box like the Speedhawk box will do as good or better job than a remap.

  17. Andy says:

    Is there any issue with fitting a tuning box to an automatic?
    Can the box be removed for servicing etc? Is this something you would recommend?

  18. BHP Plus says:

    Andy, there are no issues with tuning automatic vehicles. Our tuning boxes are compatible with both manual and automatic vehicles, working in the same way to improve your cars performance! As long as your car appears on our search application, it can be tuned. If its not however, contact BHP Plus stating your vehicle and its full spec so that we can assist you further.

  19. DC says:

    How can you say that tuning box is as good or better than a remap, also can you explain to me please how it does not damage the diesel particulate filter ? The only thing a tuning box does is increase the fuel pressure, that is it. there is absoloubtly nothing in a tuning box to prevent damage to the dpf. Also a remap will cater for everything as it will change the advance on the engine timing as well as increased fuel pressure and in some circumstances boost pressure to. a remap will mean that your car will drive exactly as normal when driving normally but will obviously have much increased performance at full throttle, a tuning box will just have increased fueling and if anything make the car worse at lower rpms due to too much fuel being pumped into the engine.

  20. BHP Plus says:

    Thanks for the question DC. It’s true that the previous generation of tuning boxes were fairly simple, and primarily worked by increasing fuel pressure. The cheapest ones were just a resistor that ‘fooled’ the engine into thinking it was cold, and caused it to increase the fuel/air mix. However, BHP Plus do not sell any of these older style tuning boxes.

    The range of Speedhawk diesel tuning boxes are able to make much more in-depth adjustments to the engines performance due to the dynamic nature of the tuning maps. The changes are made by the ECU itself as a result of different information that it receives from the injection system. With a different signal coming into the ECU, it reacts by adjusting engine parameters itself (within it’s pre-defined safe limits) which results in the increased engine performance.

    This can be seen on most of our tuning boxes: the LED light that shows the tuning is applied goes out at tickover (as it is not doing anything), lighting up as the revs or load increase.

    Diesel particulate filters should not be affected once you have selected the correct tuning map for your engine: once correctly set, your diesel engine will produce the same amount of soot particles as before. As fuel pressure is not increased at idle, you do not get the problems with smoking on idle that you did with older style diesel tuning boxes.

  21. Henry Burton says:

    Dear to whom it may concern (DC).

    How do you know what a remap does?? I have worked in the vehicle automotive industry for many years and have examined vehicles that have had a so called remap.
    It is wrong for you to say they advance timing, they simply do not (not the ones I have seen and worked with!!).
    Reading vehicle data once installed and standard I have seen that all they seem to do it increase rail pressure and also sometimes boost pressure on the turbo. They do not work in harmony with the ECU they simply just changed the data in the ECU.
    To advance timing this is a very risky business and no developer does this on a diesel as simply it is not required.
    I think you have fallen into the trap of believe what the remapper says which is the guy who just buys a map from a company abroad, not that he knows what it does but just installs like a postman delivering letters and charging for it. Its very easy money if you have the right equipment to connect to the car. I think you will see the decline to many remaps as the advance technology being used by the manufacturer is over coming already (encrypted ECU’s etc).
    Also if a tuning box plugs into the common rail sensor then all it can do is increase rail pressure, thats it, nothing else.
    The most efficient way we have seen is injection length by pulse width modulation this method is used by some manufacturers with no increase in common rail pressure, this method doesnt harm the injectors or injection system as there is no increase in pressure.
    We are starting to experience split common rails due to the pressure being increased, this is a very concerning as the common rail can be up to 1500bar of pressure. This would be enough to cause fatality.
    Over fuelling will cause the DPF to be block much sooner (The manufactures had this problem when they first introduced DPF’s or FAP’s as city driving doesnt allow the regen process to work properly but they have ironed this out now) but the ECU should do a regeneration to clear blocked DPF’s, the problem is heat, tuning causing much more heat which can cause bigger problems with DPF’s so overfulling and the heat build up may cause problems with any tuning. I know of one tuning box company that uses a unique process to overcome any problems with DPF’s, I’m not mentioning any names but its not a common rail increase box.
    My advice is yes a tuning box works but guys don’t overdo it, up to a 20% power increase is enough for a common rail increase system, or go with the systems that plug on the injectors, be very careful with flashing the ECU.

  22. Ian Ritchie says:

    Why has the manufacturer not developed the vehicle to offer the benefits your equipment offers straight out of the crate?

  23. Mark Walton says:

    Do I need to inform the insurance company of the tuning box fitted to the car or will it void my insurance.

  24. Gadjo kaye says:

    You say you have 9 preset tuning maps on each box could you explain this further please is this 9 different settings for your car varying the performance ? or are these settings there to enable the device to be interchangeable between vehicles?

  25. KK says:

    nice debate – just to let you know that people who fork out £500 for a remap are suckers for the remap marketing department. How can i say that?? because i was also one of those suckers and it still caused problems with the DPF. If your car’s going to have problems with the DPF at all – it will happen with both a remap and a tuning box. many cars have problems with their DPFs (particularly the VAG PD engines) whether they have been modified or not. The newer Common rail engines should be fine though. In terms of performance gains….. most remaps deliver lower performance than tuning boxes simply because they are designed as a one map for all driving styles etc – if you want it tailored – sure some will tweek it but urgh… the hassle.. when you can just do it yourself with a speedhawk…. often you dont actually know what you want in terms of performance when you get your car done – its only after a couple of weeks that you wished you’d gone for maximum or even reduced to try to get better MPG results. The only real advantage that a remap has is… doesnt affect the accuracy of the trip computer MPG. KK

  26. diesel chip says:

    is there any issue with fitting a tuning box to an automatic?

  27. Jason says:

    Hi I am being convinced this is the way forward I have a Laguna 3 on a 57 the new shape with an auto DCI 150S I here the conversion is good, you dont list the 150S on your selection table or do i need to just select the DCI 150 only


  28. L Canton says:

    My car just failed its MOT on exhaust readings,double the correct readings Its a Rover 75 with a 2 litre turbo BMW engine(90000 miles).I tow a caravan and it pulls well Would your box improve the readings

  29. BHP Plus says:

    Hi L Canton,

    Unfortunately not you will need to get to the route bottom of the emmissions problem first, as would always be my advice for any vehicle issues fix the problem first before modifiying anything in particular engine tuning.

  30. BHP Plus says:

    No none what so ever, in fact a good portion of our customers report that the autobox responds better with the tuning box attached.

  31. BHP Plus says:

    Hi Gadjo,

    Neither, the 9 settings are there to allow you to set the box up and fine tune it to your car, the 9 settings should not be thought of as Hi – Lo or Fuel economy and performance, simply to optimise the performance of your car with the box fitted.

  32. BHP Plus says:

    Yes, it is essential to tell you insurance company of any modification no matter how big or small, there are several modified car insurance specialists who offer competetive quotes, they are not just there to serve boy racers and serious car enthusiasts but anyone who wishes to modify the look or performance of their vehicle.

  33. BHP Plus says:

    Because manufacturers leave large tollerances, This is for 2-3 reasons one being so that vehice has worldwide appeal, fuel qualities can vary massively mainly the sulphur content in diesel, also as a bit of a marketing ploy they will launch an engine holding it back on purpose to later launch a “sports model” with more power, normally this still scratches the power of what is availalbe.

  34. Steve says:

    I purchased one of your units for my Isuzu Rodeo 3.0 Pickup. While it did show significant gains in acceleration and huge leaps in fuel economy, according to the on board computer, the fuel economy actualy dropped in real terms when measured on actual diesel used. We are talking 47.5mpg shown on the readout, compared to 27mpg when calculated to gallons used over distance!!! Quite a shock when I done the calulation. Also, the vehicle threw out loads of black smoke when accelerating (overfuelling) with the unit switched on, and this vanished when the unit was switched off. I selected a lower setting (5, not 9) and although the smoke was less, it was still apparent. If I lower any less than 5, the differnece to the driving experience is not noticeable.
    Any Ideas?

  35. Steve says:

    Should just add that the truck is only 1 year old with 13,000 miles on it and fully main dealer serviced.

  36. Paul C says:

    I don’t envy anyone installing a tuning box onto their car.. I’d use a remap anyday over a tuning box that simply overfuels, As the admin of a very large UK automotive site I’ve read too many forum posts regarding TB issues… from wiring loom fires, to fuel pumps burning out. If you want a reliable way to improve your vehicle then custom maps are the way to go, don’t be fooled into thinking something that takes minutes to install will give you better results or better ecomony figures as it’s well known that having a Tuning box fitted will make your car give you wrong economy figures..

  37. Peter Lewis says:

    Just recently i had my Mercedes Smart Cdi diesel remapped at a reputable company, and the transformation is simply remarkable.

    The remap cost a reasonable £240 and there is a significant difference in how the engine sounds and responds,the engine before was not noisy by any means, but it feels a lot smoother and is certainly quieter in normal driving.

    I originally had intended buying a tuning box and was not affraid to spent the extra cash,but however good some tuning boxes claim to be they do not physically alter the settings in the cars ECU, and through electronic impulses try to fool the ECU into thinking it is using different ECU programmes.

    A remap actually changes the factory settings in the ECU and is a permanent addition to your car,and certain boxes are incredibly expensive in relation to a quality remap.

    I paid £240 for a full rolling road remap,which also included taking the car out three times on to the main roads to test the different reponses before and after the remap.

    My engine is noticably quieter and smoother than before.

    The gear changes are quicker and even though the speed limiter was not removed my car now accelerates and goes faster than before.

    Previously i had managed close to 90mpg from my Smart, but with the totally addictive driving experience trying to drive economically is very difficult.

    Trying top locate a tuning box within the confines of the Smart engine bay was also very difficult, it would have involved cutting small holes in the engine compartment because of the engine cover and lack of available space.

    I now have nearly 70hp from my engine and so much tourque that the car feels totally different, like a new car.

    Tuning boxes maybe fine for some but i much prefer a physical change to the ECU and not a electronic unit trying to fool the ECU into thinking it has settings it does not really have.

  38. Peter Lewis says:

    As for informing your insurance,its totally up to the owner.
    An MOT station or tester or car dealership cannot physically tell whether an engine has been remapped or not.

    A Smart ForTwo Cdi according to Mercedes data figures should have around 54Hp or maybe less when it leaves the factory.

    Every standard engine is different and strangely enough my standard from new engine was pushing out 60hp before it was remapped.

    Once the ECU is remapped it physically has a new piece of software to replace the original one.

    Unless you actually tell your insurance company with the more often than not increased premium how are they to know your engine has been modified in any way.

    I would have sworn blind that the car i have owned from new only had around 50-54Hp but was really surprised to discover it had 60Hp.

    Insurance asessors can physically tear your car apart to look for modifications that will void your insurance,but examining the ECU will tell them nothing other than this engine is giving out more Hp than a standard car.

    Well my car was showing 60Hp and until my remap the engine was totally standard since it had left the factory.

    Tell your insurance by all means if it makes you feel happier, but its best to say nothing because telling if an engine has been remapped is vertually impossible.

  39. Andy says:

    I have a range rover 2.5Dse 1996 120k on the clock. It severly lacks power when going up hills. A moderate hill say about a half a mile long my speed will drop from 70mph to 40mph and drop down to third. Will this chip improve this?



  40. BHP Plus says:

    Hi Andy.

    Thank you for contacting us.
    Our tuning boxes are only suitable for the newer engines that use the common rail injection system and unfortunately your vehicle uses a different mechanically pumped system so I am afraid that our tuning box will not be suitable.

    I am sorry that we can not help on this occasion but please do not hesitate to contact us if you have any further questions or queries.

  41. Richard says:

    Can I put a tuning box out of a Vauxhall vectors into a Bmw 120d if I change the leads or will the map be totally wrong?

  42. BHP Plus says:

    Normally the map will need to be updated, but if you have one of our boxes this can be done quite easily for minimum cost. If you have one of our boxes, email our customer service team at and we’ll be happy to assist further.

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