Collating BR FAQ on TDi chip upgrades - andymc {P}
Like many others, I've been thinking about chipping one of my cars - 1999 VW Passat with the 110 bhp TDi engine, which has now reached 100k. To try and avoid repeating what's been said/asked elsewhere, I took the time to search through the plethora of relevant threads. While doing this, I realized that it's obviously a subject in which many people (including me) are interested but seem to lack a real knowledge/understanding of what it entails. So to try and help people make an informed decision, I thought it might be useful to draw up a sort of "what to watch out for" maintenance list for anyone thinking of increasing their engine power, and arrange them in approximate order of repair/replacement cost in case of consequent faults. Some I'm not sure of (I'm pretty hungover today!), but so far I've got:

Gearbox & clutch
Cylinders/head gasket
turbocharger (including any possible difference variable vane turbo makes?)
Flat spots at lower revs?

I'm also aware that different engines (eg TDi, PD, HDi etc) will all have different tolerances. Perhaps someone with more knowledge than me could give some guidance in terms of how likely/unlikely it is that chipping may lead to problems with any of the above. Any corrections or additions to the list are welcome - the idea is to share knowledge and experience. Also, it seems that there are a number of people who have gone ahead and chipped their turbodiesel with excellent results. It would be interesting to hear of anyone who has done this and regretted it, and why.

Anyway, hopefully this way there won't be a constant stream of threads all asking similar questions (saving bandwidth!). If this thread does what I hope it will, it could perhaps be linked to the site FAQ on chipping.

As for my own interest, I reckon that paying out £250 or so for Upsolute to upgrade my Passat is probably a better value option than changing the car for a newer, faster equivalent with the same level of kit. According to the Upsolute site, their chip would take power from 110 to 143 bhp and torque from 173 to 214 lb ft. Once it's out of extended warranty in February I'll probably go ahead and do the deed. However, I don't know whether an increase of 33 bhp is too much for the head gasket in that car to cope with and would certainly be grateful for any thoughts on this.

Collating BR FAQ on TDi chip upgrades - CMark {P}
Great idea and I'll start off by nominating the VW Vortex website at

Whilst this website is not so very specific to your exact enquiry it does deal with some issues involved.

VW Vortex is an american site which claims to be for the last five years, "the definitive and progressive online source for the latest information on Volkswagen brands".

I have only read a few of their articles on their own project cars but I find them to be very well written and technically sound.

Notwithstanding the fact that the website focus is primarily on VAG petrol vehicles they do have a diesel section here
and there is a particularly good set of articles about upgrading their project Golf 1.8T petrol and the one that covers ECU chip upgrade is here

Collating BR FAQ on TDi chip upgrades - Soupytwist

you may have already been there but if not :

Matthew Kelly
No, not that one.
Collating BR FAQ on TDi chip upgrades - DL
I'll be Superchipping my 110 TDi A4 very soon and will post my thoughts here.
Collating BR FAQ on TDi chip upgrades - Ben {P}
If you do chip i would use one of the other recommended companies.
Collating BR FAQ on TDi chip upgrades - DL
Collating BR FAQ on TDi chip upgrades - Ben {P}
E-mail me. Address in my profile.
Collating BR FAQ on TDi chip upgrades - andymc {P}
Thanks for the responses to date, everyone. Interesting links, especially Matt's one - it contains what seems to be a pretty comprehensive analysis of the different methods people use to get more power from their engines. According to the author on that site, installing bigger injectors seems to be the best way to achieve this (for a diesel, anyway), followed by chipping, then the tuning box - anything else is too expensive, complicated or risky.

Quote from the site:
"The European 110hp model has what are known as 0.205mm injectors, and the European "Multivan" 150hp 5-cylinder TDI has what are known as 0.216mm injectors. All of these injectors are dimensionally interchangeable, so it is possible to install injectors one or even two sizes larger in place of the original ones. This will increase fuel delivery without the engine ECU knowing a thing about it, and it will do it without pushing the limits of the injector pump, nor will it extend the duration of the injection period - and not extending the duration is better for smoke, power, exhaust temperature, and efficiency."


For myself,in terms of cost, I don't know whether having bigger injectors fitted would be a lot more expensive than chipping (I would certainly have to pay someone to do this, as I lack the necessary know-how). I'm looking at modifying a 4-year-old Passat with a view to keeping it for another couple of years, so as a percentage of the value of the car I wouldn't really want to spend more than £500 - much more than that and it wouldn't be cost-effective enough in comparison to trading up to a newer model, if increased insurance premiums are also a factor.
Collating BR FAQ on TDi chip upgrades - Ben {P}
What about fitting a better intercooler? Or even a different type. That need not be all that expensive.
Collating BR FAQ on TDi chip upgrades - Billy Whizz
Andy - changing injectors on older indirect injection engines is as easy as changing a spark plug. Just remember to ensure the old crinkle washer is removed and to use a new one.

I dunno about newer engine types, they haven't filtered down to me yet.

Off the top of my head, injectors for the newer VW engines start at around 80 quid. (Old-type ones can be had for half that.)
Collating BR FAQ on TDi chip upgrades - OldOiler
Would agree also Super chips are over priced, thereare other good companies around - should't cost you more than £400.00 incl fitting.

Collating BR FAQ on TDi chip upgrades - DL
Surely fitting 'bigger' injectors would require the fitment of a fuel pump capable of providing more fuel? I fear loads of black smoke with this modification!

I would go down the route of ECU chipping, it seems the way to go these days..
Collating BR FAQ on TDi chip upgrades - andymc {P}
My Passat isn't an IDI though, it's a 1999 TDi - precursor to the PD engines. £80 per injector doesn't sound too bad, and with labour probably wouldn't be significantly different from the cost of chipping.

Again according to the site mentioned above, the difference between the TDi 90 and the TDi 110 is the size of the injectors, although I haven't yet found out if there's a difference in the intercooler. I would have thought that bigger injectors would lead to higher fuel consumption, but as far as I remember, the official mpg figures for the 90 and the 110 were identical.

Another quote:
"Larger injectors are unique among the major power adders in that they inject a larger amount of fuel within the same amount of crankshaft rotation, and thus, for a given power delivery, they keep smoke and exhaust temperature to the minimum while also avoiding the increase in peak cylinder pressure caused by over-advanced start-of-injection timing. Given that the 110hp VW TDI engine is almost identical to the 90hp except for larger injectors, and that the 190hp "race TDI" developed by VW Motorsport uses even larger injectors but roughly the same injection timing and duration as stock, this method would appear to be the one favored by the engineers who develop the VW TDI."

I'll probably have a word with my local Seat dealer when the other car is serviced next week - he's a helpful chap & might be able to provide some information "from the horse's mouth", seeing they share the same engines. Anything else I find out I'll post here, not just for my own information but for everyone else too.

Likewise, at the risk of repeating myself, anybody's actual experience (positive or negative) of having done this sort of thing is very welcome!
Collating BR FAQ on TDi chip upgrades - Billy Whizz
yeah, where's sean when we need him???

Value my car