Have seen these on ebay:

http://www.ebay.co.uk/itm/Diesel-chip-tuning-box-Ford-Focus-Mondeo-1-8-2-0-TDCi-/170747518131?pt=UK_CarsParts_Vehicles_CarParts_SM&hash=item27c1585cb3

How and more importantly DO they work? It states 'possible' Increase in both MPG and power, sounds too good to be true..

Has anyone got any experience with these?

They just overfuel your car and make it smoke more LOL

Dont do it! If you want more power, have a proper remap! On a dyno!!

These boxes basically confuse your cars signals, into thinking it has low fuel pressure, so ramps it up... So in theory, your car doesnt have a clue whats going on with its fuel system... Resulting in a rather large repair bill... My box was on for 25,000 miles, and eventually prematurely killed my High Pressure pump and Injectors!

you will see mpg improvements if you don't use the power all the time. but if you have a heavy foot it will drop... with my box i saw 10 bhp, and 30 lb/ft increase.

If driven steadily i saw a 3-4 mpg improvement, but equally, if i used that extra power i would see a 2-3mpg drop

I have to disagree with TDCiST - Consider it as a "cheaper upgrade".

I have been a member of the Kia forums since I bought my car (not a true comaprison but) they had a discussion about this, and the different tuning boxes they can get. Some of those guys bought a few different units, most with a positive feedback - increased power, increased MPG, and no difference to the engine! no pain, no problems no heartache. One guy went out and got a remap afterwards - barely noticed the difference to his tuning box!!!

The only real difficulty with these things, is that you have to get the balance right between the settings, and sometimes whilst your getting it right, your car may lose power / efficiency / bit of a kangaroo hop whilst your finding the correct settings, however its a temporary effect, no damage and no troubles once you unplug / change to the correct setting.

Dont get me wrong, if you can afford the remap - do the remap! just if you have any warranty, it may become null and void, but if you can only afford a tune box - do your reasearch, and consider it carefully! do enough research and I am sure you wont regret it, if you dont do your research though, you could be setting yourself up for a fall!

Cheaper upgrade yes.. but definitely putting your engine at greater risk... The ECU gets its signals confused, and as a result of that... It doesn't know when things are going wrong until they go bang! I had one, and yes, i loved it, Was about £100 cheaper than a full custom remap, but now i wish i had gone down that route or a bluefin...

I agree you may not notice a difference in a generic remap, as all engines are different... but if your willing to spend the extra pounds, a custom remap, set up on a rolling road will give you greater MPG, BHP, Lb/Ft, than a box or generic remap! A tuner will often spend a good few hours on one car on a custom map.

If you want a tuning box, get it from a reputable company, not off some guy on ebay flogging them cheap.. The cheap ones are just full of rsistors that lower the Fuel Pressure Sensor values.. some of the more expensive ones can monitor it better and put the car into limp mode if it detects a problem...

I also agree with Jeebo on doing your research... DTUK have been in the business for years, as have Synergy/Roverron (Cant remember what they trade as now) however I have never heard of C.R.Tech or Bluespark Automotive... And i've been on the diesel tuning scene for a good few years now... Don't get me wrong i'm not saying it wont work or its a bad product... far from it... Just that i've never heard about them or heard form people who have them.

I personally had a Dragon Performance UK CRDII Tuning box, Which claimed 145bhp and 240Lb/FT... On the dyno on all the settings the car saw the highest reading of 122bhp and 230 Lb/Ft... Needless to say i was a little dissapointed...

Just to prove the difference they can make, here are a couple of videos from my old Focus..

0-60 Standard

0-60 With Box at Max

Dyno Run

Dyno Graphs

So yeah, they do work... I just personally wouldn't have another one...

Agreed its each to their own. It can make a difference, and if you clart around too much with the box and put the engine under the heaviest strain then you are looking at trouble, but most of them, as you say TDCiST are just resistors, and arent worth the cost of the solder to hold them together...

It really depends on what budget there is to put to this @James132, do you have the moolah to put towards a remap or are you just looking at it as a cheap upgrade?...

I can vouch for the fact that the box you are looking at is in fact a decent product. I've had a Bluespark box, (a C.R. Tech unit in fact) installed on my Mondeo 2.0 TDCi for a few years, and I'm going to swap it to my Focus soon. Its the same engine so it should be a direct swap. I've always been thoroughly impressed with it. It gave me a genuine fill up to fill up improvement in MPG, not loads but about 3/4MPG difference, and a really big difference in power output, without being in any way jerky or uncivilised. I've had other tuning boxes in the past and so have my mates, and there's nothing wrong with the Rover Ron or DTUK boxes either.

I'm sure that there are a lot of boxes out there that are just resistors, but the DTUK, Rover Ron, and Bluespark boxes aren't. Have a quick Google and you'll see quite a few threads where people have taken them apart, and they are all genuine microprocessor units.

I'm not saying there is anything wrong with remaps, I know they are a viable alternative to a box, and potentially could give better results, but there are loads of cowboys out there doing maps too. In my opinion good remaps are good, as are good boxes, and vice versa.

Glad I am not the only one on the side of the tune box ;)

Its good to get further good reviews on these models. I could provide a thread of a few very good reviews for the Cee'd but its good to see the blue oval has seen benefits as well...

Plus a Tune Box is a good way to keep a warranty... "oh look, this is broken" [ unplug tune box ] "heres the fault, we can see no changes to your car, so its a warranty repair, theres the would be bill for £1600"...

Thanks for the reply alan, very interesting to read, will have to look around and see what other reviews are like.

I was just browsing and came across them, no real intention on getting one soon, just curious to find out peoples experiences with the.

I have thaught about getting it re-mapped but as you say, theres many 'cowboy' tuners out there.

Plus a Tune Box is a good way to keep a warranty... "oh look, this is broken" [ unplug tune box ] "heres the fault, we can see no changes to your car, so its a warranty repair, theres the would be bill for £1600"...

The newer ECU's register changes... so unforunately this isnt the case so much anymore...

However, i ran one for a good few miles... in total i think i hit 40,000 with the box. only issue i had was the fuel pump. Now i know this could be coincidence, but i cant help thinking that the box helped it along on its way to an early grave.

If it had of been a cheap fix, i would still be running it! however when the quote came in at £3000, for Injectors, HP Pump, Fuel lines, Fuel Rail etc etc etc... I decided not to get a box for my new one...

I will consider a remap once the warranty period is over... Unless mountune start offering one of course ;) lol

Bluespark tuning box works great, i had one on my work car through nissan was a 1.5dci 90bhp note and with the box it was way quicker than the nissan juke 1.5dci 110bhp, had no problems with car running, totally eliminated turbo lag as my current 1.8 tdci 09 has quite bit lag now and then and plus side you can change to any car they support for £20 to re programme to chip