Remap or chip tune for 4.2tdi?

[thenobbler]

Hi all, I have a question regarding power tuning - and apologies up front if I've missed a previous thread on the subject.

I purchased a 2007 4.2tdi a couple of months ago and have been delighted with its performance and road behaviour (even if the 20" wheels do seem to make it a bit skittish over road imperfections). When I bought the car I insured it for a performance upgrade, as I was unconvinced that the power on tap would be enough. To explain, I'm an inveterate seeker of the horsepower and have owned a variety of 300 - 400hp sports cars in my time, and therefore feared that the A8 might feel pedestrian by comparison. And whilst it really doesn't, I've got the insurance and can afford to play with the state of tune, so why wouldn't I?

And that's half the question, which is: is it wise/sensible/risky/plain stupid to fettle the lump to produce more power, or should I just leave be and enjoy the standard map?. And if I do fettle, can anyone with ownership experience (as opposed to a commercial agenda ) offer advice over which way to go - remap or chip? Both Racechips and Spider seem to offer big dollops of horses and torque for not very much, with the Spider chip sounding like it'll be a really good thing from the website blurb. Obviously there are no warranty issues, so I don't care about being able to remove the amended map all that much.

I'll just add that I'm based in East Hertfordshire, so offers of tuning in far away places, while helpful and appreciated, just may not be practical...

Thanks in advance for any advice you can offer (even if it's just pointing me at the thread I ought to have found in the first place...)

Tony.

[adamss24]

The 4.2 tdi engine is very tuneable lump, however the turbochargers and fueling system are the limiting factors. Early engines had smaller turbochargers, later have gtb1749vzk. You are limited by the space in the engine bay and everything has to be custom unless you just go for a generic remap ! I have been in a new 2014 a8 4.2 tdi and whilst ok to drive, i felt the engine restrained by the smooth map. I also took a drive in a lithuanian car with hybrid turbo's and that was savagely fast- drove fine too ! I reckon i could shoehorn a pair of gtb2260vklr ball bearing turbos which will give enough air for up to 500 Bhp then add bmw 535d injector nozzles and a early CR pump for higher flow...then remap the slave and master ecu's then convert it to manual gearbox !

[thenobbler]

Thanks adamss24, that sounds like monstrous fun...if also probably beyond my justifiable budget! I'm probably happy enough to chip/map it out to around 400bhp, although 500 would indeed be a whole other world of entertainment... Are you implying that the autobox wouldn't cope, or do you just prefer a manual shift?

[c3nturi0n]

Quick update.. I recently added a chip to boost the fuel pressure and that had made some difference to an already well performed vehicle. Torque had been increased by some margin and i love the feeling of going from 50-100mph in few secs .

Cheap and cheerful diy update...


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[Slizza786]

Remap for long term use or the car. Tuning box if for short term