Engineering Department - wherefore art thou ?

[WhoseGeneration]

i'm an ex-organ-builder......bit of an expert on pipes and noises.
If it turns out to be a mechanical/poor baffle/badly made exhaust scenario, take a hammer and smash it into the silence box(es) a few times. It's amazing how that often "cures" most vibrations
Q

Tuned pipes, love those really long ones, never reproduced on one's home hifi system.
Hear them in situ, for the best experience.
The "hammer", a good idea, although probably best not to create a perfect dent, somewhat misshapen would be best.
Another approach would be to attach an anti resonance mass, that, though, being more complicated.
Poor Dave merely wants his car to feel as before this last exhaust replacement.

[TripleS]

i'm an ex-organ-builder......bit of an expert on pipes and noises.
If it turns out to be a mechanical/poor baffle/badly made exhaust scenario, take a hammer and smash it into the silence box(es) a few times. It's amazing how that often "cures" most vibrations
Q

Tuned pipes, love those really long ones, never reproduced on one's home hifi system.
Hear them in situ, for the best experience.
The "hammer", a good idea, although probably best not to create a perfect dent, somewhat misshapen would be best.
Another approach would be to attach an anti resonance mass, that, though, being more complicated.
Poor Dave merely wants his car to feel as before this last exhaust replacement.

That he does!

I'm obliged to Q for his suggestions, but I can't bung a drilled ball into the tailpipe, because it isn't a straight pipe: it terminates with a tight radius bend, so that the exhaust gases are discharged downwards. I can't say I'm keen to start bashing the system with a hammer either, as we may yet be returning it and fitting something else; but do I really need to fit a genuine Peugeot system at a cost of several hundred pounds? Is that the only answer? Is there no other reasonably priced exhaust system that will perform without causing this loss of refinement? I sure hope not, so in the meantime I think we'll be changing that engine stabiliser bush. At this rate I'm going to have a 'new' old car.

For what it is worth, I noticed this morning that there is increased vibration throughout the engine speed range, but the garage people confirm that the engine itself is in very good mechanical condition, so i don't think it is an engine fault. Previously it seemed to be pretty smooth at all speeds, apart from the resonance at about 1400 rpm, which has been there as long as I can remember. When I say 'smooth', I mean having regard to the fact that it is a two litre four cylinder diesel, and one can not expect it to feel like a turbine or electric motor - or even that much loved V12 Jaguar we had in the early 90s.

I shall just be immensely relieved when we do eventually overcome this.

Best wishes all,
Dave.

[Porker]

Dave

Does the replacement system have exactly the same construction in terms of flexible sections as the original?

(Some exhaust systems have short sections in them which are designed to flex a little to accommodate engine (etc.) movement.)

I'm not discounting the engine mounting theory either, btw. That would be one of the first things I'd be looking at if I had this problem.

regards
P.

[TripleS]

Dave

Does the replacement system have exactly the same construction in terms of flexible sections as the original?

(Some exhaust systems have short sections in them which are designed to flex a little to accommodate engine (etc.) movement.)

I'm not discounting the engine mounting theory either, btw. That would be one of the first things I'd be looking at if I had this problem.

regards
P.

Hello, Nick.

I didn't have the opportunity to compare the new system with the old one, but certainly the new system has a flexible section immediately downstream of the manifold outlet, i.e. before the pipe bends into the horizontal plane and reaches the catalytic converter unit. I imagine a flexible section is essential with most transverse engine layouts, whereas in-line arrangements might not always need it. For example, the old Mark 1 Sprite had no flexible section, but our Jaguars always did.

Gee, I shall be glad when this one is solved - and I expect the rest of you will be, too!

Best wishes all,
Dave.

[Porker]

Ah - well that would appear to answer that question.

I'm at a loss but I have to say my next port of call would be the engine mountings, although seeing the problem in the flesh might lead to a different conclusion.

Hope you get it sorted. I have plenty of first hand experience of how frustrating these problems can be.

P.

[TripleS]

I appreciate that ideally one would replaced a failed component with a genuine item supplied by the vehicle manufacturer, but in a case like this should we really be expected to suffer such a marked loss of refinement?

Admittedly the new exhaust system does its job, e.g. the exhaust note is perfectly normal, and the car performance and economy seem to be up to standard, but it does look as if by some obsure means it has introduced a new problem, so should one be expected to accept this? In view of the amount of harshness and vibration now being experienced, I would say not. Does this amount to the replacement system being not fit for purpose?

Best wishes all,
Dave.

[Gareth]

I appreciate that ideally one would replaced a failed component with a genuine item supplied by the vehicle manufacturer, but in a case like this should we really be expected to suffer such a marked loss of refinement?

You made a choice - you chose to spend less money. It's not reasonable to expect the same quality, although it is difficult to know ahead of time what the compromise is, and what effect will be most apparent when the part is fitted.

Admittedly the new exhaust system does its job, e.g. the exhaust note is perfectly normal, and the car performance and economy seem to be up to standard, but it does look as if by some obsure means it has introduced a new problem, so should one be expected to accept this? In view of the amount of harshness and vibration now being experienced, I would say not. Does this amount to the replacement system being not fit for purpose?

Given the first part of this paragraph, I would say the answer to your question is that the replacement system is fit for purpose. You made a choice and hoped for the best. It works but not with as much refinement as you'd like. Some you win, some you don't.

[TripleS]

I appreciate that ideally one would replaced a failed component with a genuine item supplied by the vehicle manufacturer, but in a case like this should we really be expected to suffer such a marked loss of refinement?

You made a choice - you chose to spend less money. It's not reasonable to expect the same quality, although it is difficult to know ahead of time what the compromise is, and what effect will be most apparent when the part is fitted.

Admittedly the new exhaust system does its job, e.g. the exhaust note is perfectly normal, and the car performance and economy seem to be up to standard, but it does look as if by some obsure means it has introduced a new problem, so should one be expected to accept this? In view of the amount of harshness and vibration now being experienced, I would say not. Does this amount to the replacement system being not fit for purpose?

Given the first part of this paragraph, I would say the answer to your question is that the replacement system is fit for purpose. You made a choice and hoped for the best. It works but not with as much refinement as you'd like. Some you win, some you don't.

I accept that it is a matter of opinion.

In my view a loss refinement to this extent is not reasonable, even though the system currently fitted is quite a lot cheaper than the Peugeot system. I'm sure we're all aware that some drivers seem not to notice anything amiss with their car until something drops off with a bang and clatter. Alas I'm not such a person.

Best wishes all,
Dave.

[Porker]

I do not agree that this sort of change is an acceptable facet of using an aftermarket component, which should in all cases be "fit for purpose".

No-one would agree (I believe) that aftermarket brake pads would be acceptable if they offered 30% less braking capability than OEM items. This is similar. Slightly worse performance might be acceptable but this level of degredation seems not to be so to me.

I should say that I've never suffered any similar problems when using non-OEM exhaust components, but my exhaust-swapping experience is quite limited.

P.

[Gareth]

No-one would agree (I believe) that aftermarket brake pads would be acceptable if they offered 30% less braking capability than OEM items. This is similar. Slightly worse performance might be acceptable but this level of degredation seems not to be so to me.

Not sure that's a reasonable comparison - I think most people buy after-market brake pads for better than standard performance and expect to pay similar or a higher price whereas the vast majority who buy after-market exhausts do so to save money. Tyres is another area where there is a range of prices, compared to what the manufacturer originally fitted, and often a corresponding range of performance.

[Porker]

I don't agree. Some buy AM pads to improve performance, but the majority buy them for price reasons without expecting a performance increase.

Even low cost pads should be broady comparable to the OEM version.

P.

[Mr Cholmondeley-Warner]

But, of course, there are two after-market markets:

The "replacement" market, where people are looking for the same performance for a lower price.

and ...

The "performance" market, where people are looking for an enhanced performance, often for the same price as OEM, but which, once they understand that nothing in life is free, usually results in some performance gain, for a variable premium above OEM prices.

The danger in the first, is that people will expect the same performance, longevity and match to the vehicle's characteristics as the OEM parts they declined to pay for and in the second, that they will expect massive performance gains for the same price as OEM parts. Neither applies...

[Porker]

I fail to see why neither should apply. The same parts from Pagid (as an example of a reputable manufacturer of brake pads and allied components) are available for 1/3 to 1/2 of the price from factors as they are from BMW dealers, and perform exactly as the branded products do.

P.

[Mr Cholmondeley-Warner]

Nick, if you can get Pagid pads for 1/3 to 1/2 of the price of OEM parts, I fully support you in the purchase of those. I'm surprised, but pleasantly so.

Are we talking Pagid blue, orange, grey ...?

[Porker]

They look kind of grey to me.

On a more serious note, the last time I had a quote for brake disks for a 944, the Porsche Centre were asking about £140 each for them (from memory). I can buy Pagid disks from Euro Car Parts for £47 each.

Not everything has such dramatic differences, but the differences for OEM parts mean that non-dealer supplied replacements are often worth seeking out.

Nick