Peugeot 306 HDi Remap Guide

A Peugeot 306 HDi remap can cost anything from £30 - £300 upwards. Detailed guide on everything you need to know if you are thinking of remapping your Peugeot 306 HDi.

The Peugeot 306 HDi has a DW10 HDi engine which replaced the XUD10 as found in the earlier PSA diesel range e.g. Peugeot 306, Peugeot 406, Citroen ZX. This engine was important at the time as it was the first PSA diesel engine to benefit from common rail direct injection (DI) as opposed to the older in-direct injection (IDI) as per the XUD.

The DW10TD as found in the 306 HDi is an 8 valve 4-cylinder turbo charged diesel engine with a displacement of 1997cc. The 306 HDi does not feature an intercooler and should put out around 90bhp and 156 lb/ft of torque as standard.

Engine summary:
bore: 85mm
displacement: 1997cc
cylinders: 4
valves: 8
turbo: K03 (or maybe occasionally a GT1546S?)
bhp: 90bhp
torque: 156lb/ft

Thinking of getting a Peugeot 306 HDi remap? Here is a little breakdown of some of the key points to consider. Starting with the benefits and then moving on to the downsides.

Remap benefits:

  • Increased power and torque
  • Better mpg
  • Improved driveability
Increased power and torque
As mentioned earlier in standard form the engine puts out 90bhp and 156lb/ft. For a car that weighs around 1150kg this isn’t particularly great and it will do 0 - 60mph in approximately 10-12 seconds. Like all diesels the HDi’s in-gear acceleration is it’s strong point and even as standard it will do 30 - 70mph in 10 - 12 seconds.

Two videos of a 306 HDi doing 30 - 70mph as standard:

With a basic ‘stage 1’ HDi remap which does not require an uprated clutch, turbo or intercooler the power and torque will increase to 125bhp and 200lb/ft. This will drop the all important 30 - 70 time down to 7.5 - 8 seconds.

Now a 30 - 70mph with a ‘stage 1’ remap:

The improvement in acceleration is clear to see although I think the second video is actually a bit too fast, maybe done slightly downhill.

Better MPG
All of the top diesel remappers will say your fuel economy will be improved due to the increase in torque and also widening of the powerband. This means you’ve got more ‘pull’ from lower revs so there’s no need to change down a gear and also no need to rev the engine as high to make good progress. If you drive the car in an economic way then this is correct, however I would say the remap also gives you the potential to get worse mpg because:
1. Remaps increase the potential amount of fuel you can use (all other things being equal you can’t get more power without more fuel)
2. The powerband will now extend higher up the rev range so there is more incentive to use these revs and take advantage of the extra power available.

Improved driveability
For many the main benefit of remapping is the improved driveability that comes from increasing torque and broadening the useable powerband. As standard the Peugeot 306 HDi feels like you’ve hit a brick wall after about 3800rpm, if you look at a dyno graph it’s clear to see. With a remap the car pulls right up to 4500rpm. Similarly there are times where you might have needed to drop a cog but now it is not necessary. When I first got my HDi remapped to stage 1 I kept thinking I was in 3rd gear but actually was in 4th because of how responsive the engine felt.

Remap downsides:

  • Cost
  • Increased mechanical wear
  • Insurance
  • Re-sale value
Obviously the initial cost of a remap is a slight downside but as we will go through at the bottom of the article, there are several options available and you can go DIY. The cost of remapping your Peugeot 306 HDi will be between £30 and £300+.

Increased mechanical wear
I’m not out to put people off remapping their engine but it is important to know the facts. As all the top remapping websites will tell you - vehicle manufacturers are required to build durable, reliable cars which can run in a wide range of conditions, on differing quality of diesel and poor servicing.

Obviously if you are effectively reducing some of these tolerances left in by the manufacturer and increasing the power output of the engine then it is logical to expect certain components are going to be put under more strain. The question is whether this extra strain is enough to noticeably decrease reliability. As we mentioned earlier a ‘stage 1’ Peugeot 306 HDi remap will increase the power up to 125-130bhp and 200lb/ft which is not really much of an ask. These engines can do 160bhp and 280lb/ft without too much bother.

You may have heard some people saying their clutch started slipping after getting a remap. This would be due to either or a combination of:

  1. Overall increase in torque.
  2. The remap has changed the torque curve so it comes in more suddenly or ‘spikes’.
A good remapper should do their best to ensure a smooth torque curve and although 306 HDi with a poor remap may feel faster due to the sudden push of torque, it is more than likely slower if timed and the driveability will be much worse. If possible ask to see a dyno graph of a HDi running the same map you are interested in and see how it looks.

Back to the point about clutches, the standard clutch in the Peugeot 306 HDi is more than capable of taking the torque increase a ‘stage 1’ remap will produce (

All this means is that it is extra important to keep on top of engine servicing (particularly oil and air filter changes) and you will be fine.

If you are already on a modified insurance policy the cost of declaring a remap will probably not be that much so it is worth asking to stay on the right side of the law. Not declaring the car is remapped is illegal and will void your insurance if you need to make a claim - this is obviously a bad thing and I do not recommend it. However - as I understand it it is very difficult for insurance companies to test for. They would have to read the map file from the ECU, open up the various maps for fuelling etc and then compare these to a standard map from the exact same model of car.

Re-sale value
Not everyone wants a modified car and remapping it will almost certainly reduce the potential market when you want to sell. Enthusiasts and regular buyers will normally prefer a standard car over one which has been ‘tinkered with’ no matter how professionally. It has connotations of bodgery and boy racers which aren’t great when you are trying to sell. Of course you can always switch back to the old map as long as you keep the flashing tool and many professional services will keep your map on file should you want to revert back to standard for exactly this reason.

DIY or professional service?
Tough question of balancing risk vs. cost. If you can get hold of a suitable ‘stage 1’ map from a friend or tuner then all that is needed is a relatively cheap ECU flasher/writer such as the KWP2000+. As I mentioned in this guide to DIY remapping your Peugeot 306 HDi this option is not without risks and in the worst case scenario your ECU will be bricked and your car will be rendered immobile. Please note this is not a guide for altering the map yourself, it is a guide for uploading an already altered map file to the ECU.

On the other hand if you take it to be remapped at a specialists you have peace of mind that it is in the hands of professionals (hopefully) and if anything does go wrong then it is their problem.

Remapping specialists will charge approximately £300 where as simply uploading the map yourself could potentially cost as little as £30.

If you want to go truly DIY and create your own remap files, you might want to have a read of our article about remap modifications specifically for the 306 2.0 HDi.

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