Tunit Diesel performance enhancer

[Geoff Bell]

Have any of you technos heard of or tried / tested this diesel engine management system. I've been told that for about £400.00 this retro-fit unit will improve power and fuel consumption by 10%. Details of this unit can be seen on www.tunit.co.uk.

[Clive]

I have had a look at the web page and it looks just like another unit that re-maps the fuel characteristic. By doing this it is quite possible to get more power and more torque. But at some cost to the emissions from the engine. Governments lay down tighter and tighter emission limits for engines each year, but the test levels for the MOT are a lot lower. These re-mapping units eat into this margin. So you won,t be quite so green! If you want to use one of these units then Van Aaken is probebly the most populer and well known - and from time to time they do special offers for MMM readers. Having more torque under your foot means that you are less likely to need to change down on hills thus making the driving experience more relaxed. Economy, I would take these claims with a pinch of salt. If more power is available you are likely to use it. Performance does not come for free. Warnings (from personal experience in most cases!) You may need to fit a heavy duty clutch. (I had to) You may need to fit stiffer anti-roll bars so it corners. (I had to) It will smoke a bit more with a heavy foot. (Mine did) If its a Sevel lump you may need to carry a spare 5th gear set around with you!. (Not me this time) The brakes may need enhancing. (Mine were OKish) Its your money. Good luck C.

[Geoff Bell]

Clive, I,ve just looked at the Van Aaken web site and they claim 30% increase to power and torque with increased improved fuel consumption. That seems an incredible increase. You talk in the past tense regarding your MH, have you still got one fitted. Their web site has many magazine articles all praising it. Do you know if any MH mags have done a test. Regards Geoff

[Nick Miller]

I have a VA Smart box fitted to my 2ltr Peugeot/Nuevo. It certainly encourages the engine to offer a little more torque when pulling up long slopes.The engine is now considerably quieter. I feel that claims regarding fuel consumption (in my case) were overstated.I still seem to average about 28mpg,Perhaps as Clive suggests if there is a little more power available you tend to use it. Ensure you inform the insurance company of any alterations.Most seem quite happy without extra premium.SAGA wanted to double the premium. I have yet to suffer any of the problems Clive sees in his Crystal Ball.Until then i think it was money well spent. NM

[Clive]

No Xtal ball but personal experience with a tuned up Land Rover Discovery. It went like a train but I had to carry out the other mods as stated to keep the vehicle handleable. I have decided that for me tuning up the motorhome is a non starter - Performance is already more than adequate and I wish to maintain its reliability. Our mate Don Madge may comment when he sees this post. Oh yes, 30% increase in power from a legal diesel is quite achieveable. If you only use the diesel off road than I have seen diesel engines provide more than double the standard power output - Specifically the BMW 2.5 litre 6 cylinder unit in some 4X4 competition vehicles. But a massive variable geometry turbo and intercooler are also fitted. Having said that the latest 3 litre Iveco diesel has a variable geometry turbo as well. Its your money.

[Mel E]

I had my Iveco base vehicle re-tuned by TB Turbo. The engine was basically the same as the Fiat 2.8 unit, but with a significantly lower geared box, it meant changing gear farv too often. The re-tune (the modern equivalent is the add-on such as Van AAken) increased HP at the driven wheels by 30% and I timed before and after 30-50 and 40-60 acceleration times, both of which fell by about a third. So it was much more driveable. There was no effect on fuel consumption (which I monitored carefully with a spreadsheet, taking account of all fuel added and all miles driven). But em issions did increase substantially, though well within the MoT limits. As has been pointed out before, however, these devices do invalidate your vehicle warranty, and with many vans now having a 3 year warranty, that's a big blow! And simply removing the device before a service will not do as the EMU of many modern vehicles can store mapping details, so they'll see you've been fiddling!!!

[Geoff Bell]

That a good point Mel, I hadn't thought about the warranty. If thats the case its a non starter for me as my vechicle is brand new with 3 years on it still to go. I'll check that out with Ford before I do anything. Thanks for all the info Guys, saved me a lot of research.

[javorb]

i am sole uk supplier of diesel tuning units ,i have been selling them for roughly 2 years now mainly through my ebay shop (diesel tuning units).my units like all other tuning units for common rail engines all do and claim similiar figures ,they all plug into the commonrail sensor ,they do alter the fuelling but they improve your engines burning of the fuel they are not worse for the enviroment as they burn fuel more efficiently ,they shoukld not effect any warranties as they do not work outside of your fuel pumps limits just within them ,they do not improve your top speed by anything more than 2-3mph as it is only the torque that gives you these increases ,i have just returned fromn doing 1300 miles in a vw 130 tdi pd golf (chipped to 155hp)whilst towing my 1125 kg (unladen caravan) it was returning 35.7mpg doing a steady 60mph on a motorway and 60 mpg solo.my previous car passed 3 mot`s with the unit fitted ,not affecting emmissions,queries to 01241873489

[Geoff Bell]

John, do you think I would benefit by fitting one of these tuning units to my Transit (2006) 2.4 TDE, What unit do you recommend and what improvements should I expect. Are they easy to fit and are they unique to each vehicle or transferable.

[spartan3956]

Ive just fitted a Dragon fueling unit to my 2.8 Fiat, the power increase is very good im able to retain 5 th gear on most hills, in fact this unit has a variable chip so you choose the power output you want. I used it on a route i take most times along the M5 south where there is a particular hill that i had to change down about half way, with the chip on full power the bottom end torque gives me so much more power im able to travel all the way up this hill without the engine labouring at all. Using the Cruise control seems a lot better. I have noticed a slight improvement in MPG at 60-65 MPH but i never push the engine i`m not interested in its top speeds. The engine feels more responsive and there is no black exhaust smoke. This unit can be removed at anytime or reset to standard fuelling. I purchased the unit for £150 off Ebay. The brakes are fine and as for the clutch its a matter of being sensible when pulling away. Pete

[enrico]

Someone mentioned earlier in this thread that if you have a warranty on the vehicle and you have anything done to improve performance,then the warranty is invalid. This is true. One garage that I ran did this to a number of cars.The manufacturer found out,invalidated all of these car warranties so I had to cover the remaining balance of the warranty.EXPENSIVEEEEEEEEEEEEEEE. You have been warned (!) (!) (!) (!)