@9designs I thought you’d actually ducked out of this one a long time ago, but you’ve come back again to try and stir the pot.
Let’s not beat around the bush. You’re an engineer, you like to try and point out the issues with other peoples ideas and you’re perhaps a bit miffed you didn’t think of the idea first or, you don’t like the idea of someone else working on something you do for a living. You’ve freely admitted you work as a consultant and specifically work in seating design, so I’m not really sure what you expect? You know the work involved in designing something, and despite you claiming ignorance on things like the Goodridge brake lines, you know as well as I do that they wouldn’t pass and OEM sign off test for any number of reasons.
You’re clearly being pedantic, hence my pedantic reply. Literally any modification you do to your car will invalidate some part of your warranty and you know that, and yet you’re still happy to replace your brake lines. Did you for instance re-measure the installed hydraulic brake characteristic once you changed the brake lines? I assume you realise that changing the stiffness of the brake lines means that the relationship between brake master cylinder and brake caliper is now changed which means that the mathematical models within the ABS modulator are now incorrect. I’ve done a lot of work calibrating ABS systems, and changing the hydraulic characteristic of the brakes makes a huge difference. The amount of brake pressure demanded by the ABS is entirely reliant on it knowing the resultant pressure in the caliper (and hence requested wheel torque), and if you’ve changed this relationship, the target pressure will be totally incorrect as the system is closed loop. There are no pressure sensors in the calipers. There’s a very real possibility that with your alteration to the brake lines, the stability of the car will be greatly affected in marginal conditions such as split mu braking. Are you confident that you can catch a yaw rate of 25deg/s when you’re not expecting it? I can tell you that the difference between a slightly sketchy moment braking with one wheel on black ice and a huge accident where you spin instantly 3 times in the middle of the road on the same black ice can be the difference between 5-10bar or a few ms. So, as I said, if you’re that worried about ‘dangerous’ modifications to your car and you haven’t got the RS development ABS software, a Continental Taves development ECU and a hydraulic characterisation rig (I think they’re about £200,000), then I guess you’ll be switching back to the OEM lines? Thought not….
Ultimately, some common sense has to be used with modifications, and being an engineer, you’re able to make an informed decision as to what is safe and what is not. I would always think twice about fitting non standard brake pads or brake lines, but would chose to do so if I felt the benefit outweighed any perceived ‘risk’. If you don’t feel that these seat frames pass this test for you, then don’t buy them. No one is holding a gun to your head. However, I think it’s clear to everyone here that you’re coming across as a slightly ‘holier than tho’ individual with no other intention than to try and smugly demonstrate your experience and knowledge. I’m not going to bother defending Jonny any more on this, but understand that we’re not all idiots on here, and you’re not the only one who has a Masters in Engineering…
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