Lotus Europa Forums > Technical Articles and DIY tools and tips
Yet Another Take on Brakes.....
EuropaTC:
Yep, another thread on brakes. I know, I’m like a stuck record at times (for those of us old enough to remember vinyl ;) )
To recap, my car is a TC running standard (232mm) front discs/calipers with a rear disc conversion using 240mm MGF discs & Renault calipers. Mintex 1144 pads up front, EBC Ultimax in the rear, no servo assistance. And it works, I really don’t have any reason to change it.
But….
The trouble with this interweb thing is that you learn new stuff, I noticed some folks commenting about Fred Puhn’s Brake Handbook and eventually tracked down a copy. It’s interesting and although some parts are irrelevant for our cars it does give you a good insight into designing and upgrading brake systems.
And that’s how it all started. So I’m blaming Fred.
Although my brakes are probably better than they’ve ever been, they aren’t “modern” brakes where you get oodles of stopping power simply by brushing the brake pedal with your big toe. I could re-fit a servo to give more system pressure and better clamping force, but decided to try another approach based on overall system design.
I may not know much about designing brake systems but as usual with me, my enthusiasm outweighs any amount of knowledge or common sense.
Right, enough background. The executive summary is that you can stop reading here if you're on 13" wheels, because what I've done won't fit, but if you have 14" or 15" wheels you're in with a chance. Actually, even if you have 13" wheels you can make a slight improvement along the same principles, just not as much.
The project was to fit larger front discs (rotors to you guys over the pond) but retain the OEM front calipers. Sounds odd ? Well, there are sums to explain the "almost" logic but the main driver was that the Elise S1 uses 288mm discs with only 2x44mm pistons in the calipers. 4 pot or larger calipers obviously give more clamping force & bigger brake pads, but not always necessary. I wanted to see how far I could push the type 14 caliper with it's 48mm pistons.
Continuing with the summary, I fitted 265mm front discs, 259mm rear discs. As expected you need new caliper brackets as well, that takes the longest workshop time. Total cost roughly £70 for discs & steel. A cheap project, one you can almost certainly get past your project manager(ess). :)
Does it work ? Yes. Is it noticeable ? Yes. I think you'd be surprised just how much so, or at least I was.
And with my usual 20/20 hindsight, I think the rear brake conversion I did a couple of years ago with 240mm discs might have been better with slightly larger ones.
Enough waffle from me. For those interested I've split it into PDF files in order not to take up too many pages on Joe's forum.....
cwtech:
Thank you, Sir, for taking the time to document your mods and sharing the info!
EuropaTC:
You're welcome, and :Welcome:
Don't take the maths as absolute, but I think the principles are sound. More road testing today and now the pads seem to be bedding into the new discs it is becoming more noticeable that the front end really dips, and that's with 250lb front springs. I just wish there was a DIY method of estimating the amount of G it pulls.
:)
BDA:
Aren't there smart phone apps for that? I have seen gizmos you can buy (don't know where or for how much). It wouldn't surprise me if Amazon sells them. They sell everything else!
EuropaTC:
I don't have a smart phone..... :-[
Yes, I know, I really should join the 21st century but phones are just one of those things that don't turn me on. I make calls and that's it really, so we've both got old Samsung things.
But.... you have got me thinking. We do have an android and an Apple tablet so if there's an app about, we should be able to cover it. Good call.
Brian
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