Brake Master Cylinder Bore Size for Lola T540

[r33rob]

My basket case T540 came with 0.70" bore brake master cylinders. A friend's T540 has 0.75" bore masters. What are the pros & cons of 0.70" vs 0.75" for a car of this era ??

r33rob

[DaveW]

No direct knowledge of a Lola 540, but generically, smaller bore means less pedal effort but more travel in the ratio of their areas (in this case, 1.15).

[Lotus7]

Pretty uncommon to have the same size at both ends on an S2000 or generic formula car. If you’re just starting out, I’d suggest a .7 front and a .75 rear until you find yourself braking at 99% capacity and can make subtle changes from there.

[old 59]

Lots of useful information on the Lola Heritage website.

http://www.lolaheritage.co.uk/2018/t...t540/t540.html

[r33rob]

Lots of useful information on the Lola Heritage website.

http://www.lolaheritage.co.uk/2018/t...t540/t540.html

Thanks Old59 for the link, good stuff.

Now for the weird part: I just recently bought this basket case T540, and I also own an RF92 !

Kinda spooky.

.... Rob S.

[old 59]

Great minds think alike….or fools seldom differ?

[DaveW]

No direct knowledge of a Lola 540, but generically, smaller bore means less pedal effort but more travel in the ratio of their areas (in this case, 1.15).

A caveat on this:
Of course, MC bore size relates directly to not only braking requirements, but also to caliper piston area plus other variables. So different calipers and tire radii, etc. front vs rear will require some calculation. If you want my Excel spreadsheet on this, PM me your email and I'll send it to you.

Brake balance calculator thread:

https://www.apexspeed.com/forums/sho...=brake+balance

[Garey Guzman]

My basket case T540 came with 0.70" bore brake master cylinders. A friend's T540 has 0.75" bore masters. What are the pros & cons of 0.70" vs 0.75" for a car of this era ??

r33rob

Lots of useful information on the Lola Heritage website.

http://www.lolaheritage.co.uk/2018/t...t540/t540.html

The Lola website has a spec sheet showing that it originally had 0.625 front m/c and .75 rear and clutch m/c. I think all my cars are the same or very close. If you have different calipers than stock LD19, you'll benefit from Dave's calculator to get you fine-tuned.

[DaveW]

The Lola website has a spec sheet showing that it originally had 0.625 front m/c and .75 rear and clutch m/c. I think all my cars are the same or very close. If you have different calipers than stock LD19, you'll benefit from Dave's calculator to get you fine-tuned.

That's probably close to what I have run in the past (35+ years ago) with an FF. Currently on my F2000 (FC) I'm running 5/8" (0.625") piston masters for all (front, rear and SAAB clutch) but the caliper piston diameters are 1.375" rear and 1.75" front.

[old 59]

Lola HERITAGE…this information is at least 45 years old. I suspect tire and brake compounds have advanced since then. It’s just kinda cool reference info on that site.
YMMV