tim-spam

Limp mode also dictates reduced fuelling of the engine, and prevents the engine from reaching high revs under load - in effect, this will restrict the level of boost and prevent engine and turbocharger damage. As for stripping the turbocharger, it looks fairly simple, but there is no mention in the article of any sealing rings or gaskets - perhaps there aren't any, but it would be good to know this in advance! By the way, before attempting to lubricate the VNT machanism, remember that the turbo gets very hot, and this may end up making the problem worse if the oil burns and leaves behind any hard deposits. My car very occasionally suffers from this problem when very cold, so I am regularly changing up at around 3000rpm when cold in the hope that it will get no worse - we shall see.... An interesting thing is that, when it is about to switch into limp mode, there is considerably more engine vibration, which would seem to confirm that it is actually over-boosting, and not just suffering from inaccurate data from the t-map sensor. This thread has provided a lot of interesting information, especially from dt1 - thanks.

Maybe......but by measurable I meant measurable on a dynomometer - perhaps around 1%, maybe 2% if the original wasn't much good. I've actually measured 'free-flow' exhausts that had a higher back-pressure than the standard exhaust, as well as being noisier. The main reason in this case was the smaller company's need to restrict themselves to standard material sizes for the internal components, and space limitations dictated that this was the next size down - oh dear. The smaller size increased restriction and also the exit velocity of the exhaust gases - hence the noise. Car manufacturers can, and do, spend millions on tooling, and, if the optimum pipe size, for example, is an i.d. of 68.5mm, then that is precisely what they will use.

The problem would seem to be that the vanes are only sticking when the engine is cold. I would not recommend thrashing a cold engine, but ensuring that the VNT mechanism gets a good workout from time to time is certainly a very good idea. As a next step, have you a method of applying a vacuum to the diaphragm from an external source? If so, you could try exercising the mechanism manually with the engine cold - I don't know how difficult this would be however, having never tried it myself. If it was possible, however, it may scrape away some of the deposits and help to free up the mechanism. By this, I mean manually forcing the rod to move through its full travel several times. You may find the following interesting: www.technologie-entwicklung.de/Gasturbines/VNT15-Turbo/vnt15-turbo.html Failing this, either cleaning your own turbo, or fitting a reconditioned unit is the only real solution. There are a few turbo reconditioners out there who will charge a lot less than a main agent for the parts.

It's really quite simple. The car industry spends huge sums of money trying (and succeeding) to improve the performance, economy and comfort of its products. Exhaust systems have an effect on all three of these, and a great deal of effort is put into meeting the backpressure requirements of the engine (this is vital in ensuring that the power, economy, emissions and noise requirements are met), the quality (not just the quantity) of the noise made, serviceability and durability (both in terms of corrosion resistance and fatigue life) and, of course, cost. Now, if the cost constraint is removed, and with access to all of the analytical and test equipment available to the average car company, it may just be possible to achieve a measurable improvement in efficiency, but it would be very small indeed. However, if you are after a different sound and a smarter look, a special exhaust could be just the ticket. It may be difficult to find one made for the Galaxy - you could try some of the German companies who produce tuning parts for VW group cars. Good luck.

If you really want to believe that a 'performance' exhaust on its own can give you any significant improvement to either performance or economy (were you claiming around 15%?), then go ahead - it's your money.........

There must have been a pretty serious flaw with your original system (baffles adrift/misaligned, partially blocked, basic design wrong, etc). On a properly designed modern car, it is very difficult to obtain any significant improvement in either performance or economy by changing the exhaust alone. A Galaxy exhaust system will have been properly designed and matched to the rest of the engine systems. But, if you really want to go ahead, then go ahead - it's your money.

Yes, Michelins are perfectly fine - it's just that there are many other tyres out there that are far better, made by reputable manufacturers who do their own considerable R & D. Vredestein and Nokian are two such companies (both Western European). However, I totally agree with you about the real cheapies from China and the like - no significant R & D spend, living off the backs of other reputable companies and producing products of questionable quality.

Magic!

Except when it's Michelin - usually the most expensive, and definitely no longer anywhere near the best - you are paying an awful lot for the name.

The treadwear figure is supposed to relate to tyre life - the higher the figure, the higher the life. However, this figure is a bit like official fuel consumption figures..... My old Dunlops were treadwear 200, and were noisy and pretty hopeless in the wet. The Continentals on my Wife's Merc were treadwear 280, and were quiet and OK in the wet. The Nokians on my car are treadwear 320, and are reasonably quiet and grip very well in the wet. As for the real budget tyres, I tend to avoid them - after all, why does a tyre 'not balance'? One suspects that quality may not always be what it could be....

By the way, if you need a new driveshaft or CV joint, try GSF, as they are likely to be considerably cheaper than the main agents.

If Ford has a problem in being able to supply just the failed part (rather than the whole drive shaft), it may be worth giving VW or Seat a try - I have found my local VW agent to be the best source of dealer supplied parts. It might also be worth trying Eurocarparts or GSF - their prices are generally much lower than main agents'.

Something must be wrong somewhere, as 2001 should be Y/51.

This could be a possible cause of the sticking VNT - it will be spending a lot of time in its maximum boost position, whilst there are sooty deposits accumulating on the mechanism. I have heard that some people have improved / cured this problem by changing their driving habits to regularly use higher revs, changing up at around 2500-3000 rpm, even when cold, and using up to 4000rpm at least once a day.This forces the VNT mechanism to move through its full travel regularly, preventing the sooty deposits from building up sufficiently to cause the mechanism to stick.

Unless the exhaust is a principal element in limiting the performance (which it won't be), you are very unlikely to gain any significant performance or economy benefit from a 'performance' exhaust, unless other engine changes are also made (head work, remap, cam, induction, etc.). If, however, you are just after a different sound, it may be just what you want. Thinking about it, though, if the 'performance' exhaust was noisy enough to encourage you to change up earlier, you may improve economy slightly. But then again, if it sounded really good, you may spend more time revving it to the red line - then economy would go out of the window.

The CV joints will have been designed to work safely and correctly over the full range of suspension travel and steering lock, so there should be no problem there. However, regularly accelerating hard at or near to full lock will greatly shorten the life of the outer CV joints, as their torque capacity reduces as the lock angle increases.

When my wife's Merc had a screen replaced a couple of years ago, I watched the job being done. All trim parts were literally ripped off with no care whatsoever - it was only due to the quality of the Merc parts that it all went back together in reasonable shape.

Does it go into limp mode every time after a cold start, or can you avoid it by driving gently until the engine is warm? To avoid this problem being caused by a sticking VNT, it is a good idea to regularly use revs up to and exceeding 3000rpm. This ensures that the VNT mechanism gets regular exercise - if you regularly change up at 2000 to 2500rpm, the mechanism will spend most of its time in the 'full boost' position.

Why not?

So does that mean that the replacement you have is not the new uprated one at all, but old stock with the new part number superimposed over the old part number?

Yes, but, as has been pointed out before, the real replacement for the current car is not due out until next year.......

Cheap 'universal' antifreeze uses a silicate based corrosion inhibitor, which is fine for older engine designs, but more modern engines (from around the early 1990's) run higher cylinder head temperatures due, amongst other things, to tighter emissions regulations. This would cause the silicate based corrosion inhibitor in 'universal' antifreeze to degrade at a much higher rate than hitherto, and lose it's corrosion protection properties - even on older engine designs, the recommended change interval is 2 years. Replacing it more frequently in a modern engine is not a good idea either, as it works by coating the internal cooling system surfaces to protect against corrosion, and the increased deposition can cause blockages, especially in the more efficient radiators fitted to modern cars. The more modern (usually pink) organo-acid based antifreezes use a completely different corrosion protection strategy and are not subject to the deposition problems of the older traditional types. These must be used in more modern engine designs. I'm not sure what category the VAG G11 green coolant falls into, but if you use the G12+, you shouldn't go too far wrong.

If you're brave, you could get someone to try driving backwards whilst you look under the car (from the front - don't risk getting run over if something grabs) to watch the driveshafts - if an outer CV joint has failed, you may see one of the driveshafts turning, or one of the output flanges turning if it's an inner CV joint that's failed.

So, basically possible, but risky. In that case, as I'm about to have a new garage roof, I shall make sure that a beam is incorporated of sufficient strength to support a winch.

Is it not possible to support the engine on a trolley jack during removal of the gearbox? The reason for this question is that, should mine ever need doing, I will do it myself (and I always like to be prepared). In addition, there are some who say that removal of the complete offside engine mounting also requires the engine to be supported from above, but I found it completely satisfactory to use a trolley jack from below when changing the cambelt.