Lotus Elan and Lotus Elan Plus 2 Forums

Morning,

I have discovered the discs used used on the baby elan are a different size to those used on the +2. http://gglotus.org suggests either gt6 or mk1 spit discs, but the originals on my S3 (with servo) are 9" while the ones I have just bought are 9 5/8". The larger discs (I guess GT6) don't fit the original calipers either.

However, given I have now purchased the larger discs and also have a pair of +2 calipers, are they interchangeable and is there any benefit to fitting, or should I obtain a pair of the smaller discs? I have the standard elan wheels with spinners.

Thanks in advance for any suggestions.

Cheers,

David

Well used and well regarded swap to stick +2 discs/calipers and caliper brackets on the 2 seater.

Stay with standard set up and keep the un-sprung weight down. Aluminium 4 pot if feel the need.

Plus one on heavier components. There is a significant difference in weight between the type 14 and type 16 caliper. The larger disc is just more rotational weight that has to be accelerated and stopped. Would you add more weight to your flywheel? Same goes for increasing the wheel and tire size.

Yes, a substantial weight gain. Those larger calipers are boat anchors.

You would also need to swap in the caliper mounting brackets for the larger calipers, necessitating dismantling the uprights.

Isn't there also an issue with the hub clearing the caliper? I believe that's true at least with bolt-on hubs that use the smaller Herald/Spitfire stub axles and bearings. I'm not sure about knock-ons but I think I remember a thread here where Gary Anderson showed two different hubs in profile, one being larger to accommodate the larger caliper.

Paddy

the clearance between the 16 calipers and the stock 4.5" steel rims may be tight: a bit of grinding can remedy that for peace of mind (in case of flex if very sticky tire are mounted).

As for the added weight vs. braking, true this adds non suspended weight, but to be needing (and feeling the difference of) that added lightness one needs to push his/her elan quite far - then when doing so without the perfect skills required extra braking power can be of help, and extra heat capacity as well, imho biasing favorably the move compared to stock setup.

I prefer that kind of period correct mod to modern 4 pots alloy calipers, and it stays within the family as far as supplies go. There is also the option of AR alloy calipers for improved performances, though an order of magnitude more expensive probably (and would only make sense on a adequately prepared car, a whole project in itself).

16 calipers (with the required Plus2 disks and rotor brackets, as mentioned above) is an easy and fully reversible mod, and it mostly adds braking to a road car. Not everyone needs it, obviously the car goes very well without, but for the tinkering kind that already has tried several pads it's an easy one (easier than say, swapping camshafts and retuning, for picking a somewhat equivalent in the engine department).

Installing larger calipers will increase the volume of brake fluid required to move the pistons. You might need to change the master cylinder in order to get a firm pedal.

Everything above good advice, but I would add:
The +2/GT6 Girling type 16 caliper requires the +2/GT6 Upright unless you are very fortunate and have the Spitfire/Herald 2-part upright (rare) in which case you can "just" change the mounting bracket. If you need to do this, go to Canley Classics and buy their alloy mounting brackets:

https://www.canleyclassics.com/suspensi ... r-brackets

As far as the need for a +2 setup is concerned, depends on individual preference, muscle development in right leg and servo'ed or not, but a lot of the wise heads on here focus more on choice of pad. Personally I think this is crucial but there are a lot of pros and cons, particularly for road use where you might want to be EU road legal (pause for the Brexit arguments, but don't think the politicians here won't cock it up as well!).

If you're actually concerned about stopping and arguing the case afterwards there are a lot of good pads. Then it down to temperature, dust and cost.

Paul

Hi,
The standard 0.7 master cylinder is good for both type 14 and 16 calipers - same size is used for Elan and Plus 2
One of the better mods for an Elan.

Regards
Steve

Hi,
I thought that Elans always came with 2 part upright? unless early cars had one piece.

Regards
Steve

I think this is the thread that Paddy is referring to viewtopic.php?f=42&t=19846
Brian.

Well done for finding it.

Full link: viewtopic.php?f=42&t=19846

Paddy

The + 2/GT 6 barke and upright also gives you the larger, stronger spindles.
The original spindles were famous for failing magnaflux (9 out of 12 failed for me in the '70's) and breaking under track conditions. Yes, modern metallurgy is better but stronger is better with super sticky tires.

The original brakes will cook the fluid and pads at some tracks and probably descending an Alpine pass or similar.
The uprights also increase front track slightly.

Eric
64 S1 Hart