Coils

[warpc0il]

This is exactly what happens, though it doesn't always work out for the best.

This example is slightly off-topic but shows what can happen.

The last model of the Ford Escort was designed with symmetrical rear light clusters, e.g. the same both sides.

Some bean counter at the production plant knew that the UK regulations only require a single rear fog light and a single reversing light, so he saved a couple of quid on each UK car by not fitting a couple of feet or wire, the bulb holders and the bulbs.
The nearside had a working reversing light and a (glued-in) blank in the rear fog position.
The offside had a working rear fog and the blank in the reversing light.

I had one of the first production cars and initially thought that something was broken.
Having lifted the boot carpet and seen what had been done, I walked up to the Escort Brand Managers office, in the same building, to ask if she was aware and had sanctioned the change. Not only wasn't she aware but she was livid and it triggered a big row between Marketing and Production Engineering.
PE insisted that it saved so much money that they had given the bean counter a bonus for his initiative.
Then Sales & Service got involved because so many customers were taking their new cars back to the dealers to have this "fault" fixed.
Customers weren't at all happy when told that this wasn't a fault but a deliberate decision.
Then the Parts division got involved, as they now needed to source, stock and manage different parts for the rear looms and both rear light clusters, for UK compared to other markets, whereas they would have otherwise all been the same.

The Escort Brand Manager had a contact in Parts that was able to show that the additional parts management costs were over three times the savings made in production - though it all came out of a different budget.

She wasn't able to put a financial cost on the negative impact in customer perception.

Thankfully there was enough of a storm to prevent the production plants from doing the same thing to the Galaxy and Mondeo.

Some enterprising dealers put together a kit including a couple of feet of wire, bulb holders and bulbs, and offered this as an over-the-counter diy fix, or supply and fit in their workshops. They did quite a good trade for a while but Ford didn't see a penny of those profits.

[PeteH]

Another example (this should have it's own thread....). The first Metro came in various trim levels. The base specification was the only one that came without a digital clock in the middle of the dashboard. That version was, of course, the cheapest version, and didn't sell in huge numbers. But the clock was deleted because marketing insisted on "model differentiation". Unfortunately, the cost of having a specific dashboard just for this version was much higher than if every car had come with a clock. And that was just the piece part cost in the factory, before factoring in the extra spare parts inventory, storage, part number duplication, duplicate drawings, and so on.

[350matt]

sounds like classic British leyland practice

you know they didn't make money on the mini ( their biggest seller) until about 1979 as they priced it too cheap by £1
so lost a £1 for every one they sold...... so about 3 million cars

now in 1959 when the whole car was £500 a quid was quite a lot

[warpc0il]

The government financial support for BL was explicitly not meant to subsidise the production costs and allow BL to undercut the competition, particularly other UK-based operations.

Ford got hold of a Mini, reversed-engineered the production process and proved that they couldn't make it for the wholesale price. Therefore the government funding was subsidising and the price should be increased.

What Ford didn't know at the time, and only came to light later, was that Ford's processes were significantly more efficient than BL and the cost/price deficient was even wider than they had calculated, more like £40 per car or 12%.

Such was the politics around nationalised industries and it is now clear that Fiat, Renault, etc were even worse.

At least it made the new cars cheaper in the showrooms, even if the build quality was crap.

@RobinPZ72 Sorry mate, your thread has gone off in a tangent, again

[RobinPZ72]

Ha ha mate nothing to be sorry for!!

This could be a delicate question, but I'm not known for not putting my foot in it! I wonder how many oem coils have been changed due to scaremongering, inexperienced mappers tweaking settings cause they know best or just completely wrong diagnosis and could be purely the HT-lead end needing adjusted for better fit!

There's plenty of Del boys out there that would take advantage I'm sure, but this is why forums like this are great as new and experienced owners can learn more!

[PeteH]

I agree that "swapping the coils" is an easy answer, and we go through a huge amount of coils on RX-8s. My view is that a lot of coils fail due to the load placed on them by old, cheap, poor fitting HT leads, and by spark plugs that are well past their service life.

If the Mazda HT leads were better, and the plugs were cheaper (so were swapped regularly) I bet the coils wouldn't be such a concern....

[RenesisRaceBuggy]

Quite probably, the OE leads in particular are terrible - I don't think I got a set to even last one full event.

[RobinPZ72]

Aye that's what was mostly wrong with mine faulty HT leads two where basically not connected, but the Mazda dealer couldn't even figure it out! I was the laughing stock of these idiots as I bought a duffer, but why do technician (as that's all they are these days) think everyone is clueless and how dare you question there ability.

I do like the acting stupid bit though to see who's who!

[Azimuth]

What is it about the spark plugs that makes them so much more expensive? I used to think fitment was the major difference between different plugs. Of course the firing rate in an RX8 means they would have to be a bit more robust, but I find the actual vast price gap quite perplexing.
You can outfit 4 Lotus Esprits with plugs for the cost of 1 RX8, or even 2 straight 6 Porsche 911s!

[RobinPZ72]

I think it's because of the manufacturing numbers are far less for the RX8 than the Lotus as there engines are either Toyota or Renault units which are mass produced! There is others that make plugs for the RX8, which are cheaper, but if someone can make something cheaper I'd be suspicious, which corners was cut! Never ever to the benefit of the consumer!

https://www.sparkplugs.co.uk/denso-raci ... g-irl01-27

https://www.sparkplugs.co.uk/denso-raci ... g-irl01-31

Tend to be good plugs, but who's tried them?

[350matt]

with those Denso plugs do you get both plugs for the £24? as thats a good price and Denso are a good make

[13Black]

I recall hearing on the grape vine that a few of the Denso plugs fell apart somehow for some reason. Might have been Essex Rotary.

[Eddie_r32]

I recall hearing on the grape vine that a few of the Denso plugs fell apart somehow for some reason. Might have been Essex Rotary.

I think rrp had a denso take out An engine when it fell apart

[RobinPZ72]

Yeah used Denso a lot in the past and never failed, but the price difference was never that much and probably the same a NGK. There is a few more variables, so maybe the ones that got tried were the wrong ones!

There's these too https://www.vividracing.com/hks-mseries ... 00243.html

[Ryan Rotary Performance]

Yeah used Denso a lot in the past and never failed, but the price difference was never that much and probably the same a NGK. There is a few more variables, so maybe the ones that got tried were the wrong ones!

There's these too https://www.vividracing.com/hks-mseries ... 00243.html

Why move from the tried and tested unless you need cooler plugs for FI, in which, Rx7 plugs will do

[RobinPZ72]

If we don't try new things we'd all be just using OEM, which yes tried and tested, but sometimes there can be a better option!

We should do blind testing if the difference is so much we should be able to tell!

[RobinPZ72]

Merry Christmas everyone!

[RenesisRaceBuggy]

What is it about the spark plugs that makes them so much more expensive? I used to think fitment was the major difference between different plugs. Of course the firing rate in an RX8 means they would have to be a bit more robust, but I find the actual vast price gap quite perplexing.
You can outfit 4 Lotus Esprits with plugs for the cost of 1 RX8, or even 2 straight 6 Porsche 911s!

Because most plugs vary just in heat range, tip material and protrusion length, so the same basic design and equipment can be used for many plugs and most plugs will be used across a dozen models which spreads costs.
RX8 plugs are surface discharge, a different design to almost every other plug out there, and which aren't used in anything else, so all the manufacturing costs means they're much more pricey.

[Azimuth]

Because most plugs vary just in heat range, tip material and protrusion length, so the same basic design and equipment can be used for many plugs and most plugs will be used across a dozen models which spreads costs.
RX8 plugs are surface discharge, a different design to almost every other plug out there, and which aren't used in anything else, so all the manufacturing costs means they're much more pricey.

Ahhhhh. Nice explanation, thanks! I hadn't realised they were intrinsically different.

I remember reading somewhere that Mazda had been experimenting with Laser and Plasma "spark plugs" with their RX-Vision concept, so I guess it could always be worse!

[350matt]

surface discharge plugs are used a lot in racing engines mainly beacuse the increased running temperature / duty can lead to the side electrode falling off.....

typically a racing plug is at least £25 apiece and can run to £125 each

so I think our plug price isn't so bad to be honest

what i'd like to see tested / tried is a multi spark event on these engines as thats been proven to help improve combustion on other engines

[warpc0il]

In the early '90s the Spitfire spark plugs were being heavily promoted, especially at racing meetings, car and bike shows, etc.
With claims that they could increase power by x% and reduce fuel consumption by y%, they were increasingly popular with those trying to see such improvements.

Within a few years there were also increasing instances of engines dying with holed pistons or burnt exhaust valves, having switched to these plugs.

Not only was the whole technical/sales premise bogus but they didn't produce the correct temperature range equivalents or have appropriate production quality control. The plugs would either run much too cold, and foul-up, run waaaay to hot and burn-up, or just fall apart inside and destroy the engine.

Even if they didn't damage your engine, there was no evidence of any of the claims being substantiated.

It was a clear case of "if it was really that easy then all manufacturers would do it, as standard", very much like the HT lead "spark amplifiers" and other such snake oil.

Update: I just googled "Spitfire spark plugs" and found this
https://www.ftc.gov/news-events/press-r ... claims-are

[RobinPZ72]

Yeah had them Splitfires in my RD500, but they just couldn't cope when things got screaming and my naughty swabrics sang!

Just checked and they do list them for the RX8 too!!!!!

[RobinPZ72]

http://www.rotaryeng.net/Spark-plugs/Spark-plugs.html

[warpc0il]

The most common causes of premature failures on Renesis plugs are;
- water/salt corrosion on the outside, due to poor sealing of the OEM HT lead connections; which result in the end falling off and/or rust marks tracking down the insulation.
- owners/garages "cleaning" the working ends of the plugs and either damaging the plating or the insulator ceramic surface, or contaminating that surface with brass or steel from wiring brushes.

Surface discharge plugs mustn't be cleaned with anything more aggressive than a soak in suitable solvent (e.g. Seafoam, carb cleaner, Cataclean or alcohol) and a soft cloth or non-metallic (plastic or bristle) brush.

[RenesisRaceBuggy]

I just used to heat them up with a torch to burn the carbon and deposits off, never needed more than that.