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better big brakes on a budget

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bowen6951 Avatar
bowen6951 Gold Member rob bowen
Fontana, CA, USA   USA
Hi Todd,
I'm sure in the next 75,000 miles (10 years or so?) I will make some kind of a change in my brakes as that is what we do to these cars. Glen told me strength would not be a problem with the aluminum brackets he made for me and I trust his knowledge. Could you start a new thread on your drilling and pinning of liners for the 4.0 & 4.6 as that has been a concern of mine for my future project. Thanks, Rob

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TeamEvil Avatar
TeamEvil Thomas C
Kingston, MA, USA   USA
Been privy to Todd's Big Brake Fetish for some time now and have driven a TR7 and three TR8's but didn't find the brakes on either car lacking for regular use. Maybe I wasn't paying full attention, but are the factory brakes on these cars SO terribly bad that this amount of caution needs to paid?

I know that in extreme instances, panic stops and the like, a bigger better braking system pays off, but thinking that if most of my driving is around town and expressway and the stock brakes are adequate for speeds under 60, that regardless of how big of a motor I the car has, stopping from sixty will remain adequate. In other words, the car doesn't really know how fast it got there, just that it's now gotta stop.

I'm asking for a general consensus from TR7 and mostly stock TR8 drivers as I'm still pretty committed to grabbing up one of these little treats and I know that Todd will be all over me to improve it, which I will totally resist . . .



Edited 1 time(s). Last edit at 2016-12-18 04:05 PM by TeamEvil.

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TR8todd Avatar
TR8todd Todd Kishbach
Mass, USA   USA
1977 Triumph TR7 "Rally Fraud"
1978 Triumph TR8
1979 Triumph TR7
1980 Triumph TR8    & more
Tom your partially right. We all know the benefit of big brakes when it comes down to shedding heat buildup in the brakes. Thats not really going to come into play the way you drive, or even the way I drive 99% of the time. The real benefit of the bigger brakes in a street car is the brake feel, and repeatability. The larger diameter rotor and and good brake calipers, allow you to apply braking force more evenly. The better the feel, the easier it is to achieve minimum braking distance in a panic stop. Go out and panic stop 10 times with stock brakes and then 10 times with bigger brakes, and you will see a noticeable difference in braking distances. With the bigger brakes, its so easy to brake right up to the limit of tire adhesion and then let off a little. You really need to go for a ride in Al's car, or once the beast is done take that out for a spin.

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Sydney.Wedgehead Sydney Wedgehead
Sydney, NSW, Australia   AUS
For the last 10 years I've had Volvo 4 spot calipers and 254 mm vented discs on the front and found the brakes comparable to my modern daily driver (with no rear upgrade).

I upgraded as the original TR7 discs reached end of service life and I'd always felt the brakes were the weakest aspect of the car.

With the front brake upgrade it's great, except when travelling down the side of a mountain, during which the brakes get hot and the pedal gets longer.

I think some cooling ducts from the front spoiler would sort this out. What would be ideal is an aluminium back plate that matches the rotor/disc size and facilitates a flex-pipe coupling.

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JTopper Joe Toporcer
Warren, OH, USA   USA
Todd,
Great post! A few years late, but really enjoyed reading about all of your hard work and R&D. With your brake upgrades, what master cylinder are you using? I have upgraded to the volvo 4 pot calipers and 10.5 inch discs. I'm now in the process to upgrade rears to discs and wondered if I needed to upgrade master cylinder also. After reading you post, I'm thinking about going with the even large front discs.
I have autocrossed for years with my 8 and the last 2 I have been going to track day events. A little more braking power would be great. Any info you could pass on would be great.

Thanks for your help,
Joe Toporcer

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TR8todd Avatar
TR8todd Todd Kishbach
Mass, USA   USA
1977 Triumph TR7 "Rally Fraud"
1978 Triumph TR8
1979 Triumph TR7
1980 Triumph TR8    & more
Master cylinder sizing all comes down to math. You can find online calculators that ask for bore sizes, number of pistons, pedal length, etc. Plug in the numbers and see what it spits out. Takes some reading to learn this stuff because some of it is counterintuitive at first. Short answer is if you have more piston area in your calipers you will need a larger bore sized master. The larger the bore size master, the harder it is to push the pedal and the less line pressure you send to the calipers. But if the calipers have a larger bore size, that lesser pressure acts over a larger area and give you back the same clamping force on the pads. I have driven some 8s with big brakes and larger masters. Even driven some with no booster and different masters. Some you don't even notice things have been changed, and some require more pedal effort. You need to start with a big picture plan and work backwards to the master. Figure out what calipers you want to run based on weight distribution of car and front to rear braking bias. Then you figure out what line pressure you need to have in a panic stop. There are limits to this pressure and desired ranges. Then using pedal ratio, with a max pedal effort exertion of 100lbs or so, calculate what size master you need to give you that line pressure. Adjust bias with a proportioning valve or bore sizes on pistons. Throw some specifics my way and we can have a math class right here on the forum. Start with front calipers. I'll make it easy for you. Start with Wilwood Dynalites or Dynapros with 1.75" pistons. Anything else is just overcompensating for a lack of size in another department. Now figure out what you want or have for rear brakes.



Edited 1 time(s). Last edit at 2018-10-30 06:43 AM by TR8todd.

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JTopper Joe Toporcer
Warren, OH, USA   USA
Todd,

Thx for your help,
Joe

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pdx7 Bruce Fogerty
Wilsonville, Bend, OR, USA   USA
Todd:

Is your friend Glen still doing his brake upgrade? I'm ready to pull the trigger on this ASAP. Can you PM me his contact info?

Thanks, Bruce

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TR8todd Avatar
TR8todd Todd Kishbach
Mass, USA   USA
1977 Triumph TR7 "Rally Fraud"
1978 Triumph TR8
1979 Triumph TR7
1980 Triumph TR8    & more
I'll send you a PM with Glen's phone number. If you ever have the occasion to go into Pine Mountain Sports in Bend, say hi to the owner Dan. He's my cousin.

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dursley Avatar
dursley Russ Cooper
Dursley, Gloucestershire, UK   GBR
I run Toyoya Supra 2.8 vented discs on my TR7 with a usual type of hub adapter. They are 258mm diameter, 20mm thick and fit nicely inside 14" wheels. Being a standard part they were also pretty cheap.
My calipers are the Princess 4 pots which have 38mm pistons as these are readily available in the UK and bolt straight on to the struts with no modifications, but they would also go nicely with the usual Willwoods as well.



Edited 1 time(s). Last edit at 2018-11-30 08:33 AM by dursley.


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sbs Avatar
sbs Steve S
Oops, responded to 2 year old post...



Edited 1 time(s). Last edit at 2018-11-30 09:15 AM by sbs.

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TR8todd Avatar
TR8todd Todd Kishbach
Mass, USA   USA
1977 Triumph TR7 "Rally Fraud"
1978 Triumph TR8
1979 Triumph TR7
1980 Triumph TR8    & more
I prefer to think of this as a legacy post. Lots of info for frequently asked questions. The stock brakes are seriously lacking compared to what modern cars can do, so upgrading makes sence. Once you drive a wedge with good brakes, bigger wheels, better tires, and a sportier suspension, the desire to have a bone stock wedge goes away. Modify? Keep stock? That comes down to whether you would rather drive the car, or stand next to it in a field with other British cars.

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robtr8 Rob Stephenson
Lake St Louis, MO, USA   USA
Rimmer has a sale going on the Vitesse derived upgrade. Other than unsprung weight, is there a downside to this kit?
I like the idea of no "adapters". I'm pretty much a plug and play kinda guy.
I would like a better range of pad availability though. I put Akebono Euro Ceramics on everything I can.



1980 TR8 - MBT-RX, Overdrive Plus, GM-D9605, GS62, TS-SW2502S4 (2X), Glenn's Wilwood kit, Ted's everything else.
2006 XC90 V8 - AVH3300NEX, PDX-F4 (2X), PDX-M12, GB10, GB25, AR6K, GB12D4 (2X), Craven, IPD.
2008 328xi - AVH7800BT, GM-D8604, GM-D9605, MT230, GB40, XE 200, Primo 12"
2011 XC60 T6 RD - She won't let me.

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TR8todd Avatar
TR8todd Todd Kishbach
Mass, USA   USA
1977 Triumph TR7 "Rally Fraud"
1978 Triumph TR8
1979 Triumph TR7
1980 Triumph TR8    & more
Braking comes down to a few things. Ultimately the most impoirtant two items are friction between tire and road, and the friction between pad material and rotor. Lets assume the tire to road interface isn't going to change when you install bigger better brakes. Lets also assume you can lock up the wheels with the brakes you have. What now makes the brakes better or worse? Being able to cast off heat generated by the brakes, repeatability in multiple hard stops, and how easily can you apply the proper amount of pressure to brake at the limit without locking them up(modulation). Heat... the brakes you propose are bigger and much heavier. They can absorb more heat than whats there now, so they are better in that respect. Vented rotors will go a long way towards disapating heat compared to solid rotors. Does this kit come with vented rotors? Vented rotors are heavier and can absorb more heat, plus the added cooling slots help a bunch. Clamping force will increase if the brake piston surface area is larger. If its larger, increased pedal travel will bve required. Modulation comes down to pad friction material and the diameter of the rotors. Pad material can be changed around if there are enough different styles available. The larger the diameter of the rotor, the easier it is to control the braking force exerted on it. How much larger are these rotors, and how many different pad materials are avialble? So you need to ask are there enough friction materials available to allow you to do what you want with the car? Can you live with all that extra weight effecting handling and rotational acceleration? Are these rotors big enough to actually have a noticeable effect on braking repeatability at the threshold?

For me the answer is no, no, no. Give me a set of aluminum calipers with a very wide selection of pad materials, and the biggest, lightest, vented rotors I can fit under my wheels. And,,, make it as cheap as possible. Really good front brakes like this for a wedge can cost you anywhere from 700 to 1200 depending on what level of extreme you want to go to. Cheaper if you can fabricate the brackets on your own.

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robtr8 Rob Stephenson
Lake St Louis, MO, USA   USA
Sorry for the thread jack but this seems like a good place to stick this.

What I have, so far. Wouldn't mind an extra set of eyes to check me.

Rimmer's new kit is based on SD1 Vitesse calipers.
Requires no adapter to mount but they're heavy, as Todd mentions.
The discs are an unknown at this point. Not sure if they are readily available here in the states and require modification to mount.
Use 1989-1998 Discovery pads STC2956P. There are Green Stuff, Mintex and Brembo versions. None of which appeal to me.

Ted's kit appears to be Jag E Type calipers and pads from 1969-1974.
Pads are D83's.

Steve's (S & S Preparations) kit that Russ mentioned uses Princess 4 pot calipers which are NOT readily available in the states and are heavy.
S & S makes the adapter so you can use the Toyota Celica Supra disc #NBD269 which is readily available here, cheap.
The Princess caliper takes a Mintex MLB52 pad.

Glen's kit uses Wilwood #120-6806 calipers.
He supplies everything to mount the Wilwood's.
His kit includes Mini discs that he modifies to mount to our hubs.
Wilwood has a compound (Polymatrix Q) that, in talking to Wilwood tech support, appears to be similar to my prefered Akebono compound (Euro Ceramic).

At this point my first choice is to resolve using Glenn's kit to mount the Wilwood's with Steve's adapter to use the Supra discs.
This is based on the theory that if I'd ever have to change discs, I wouldn't have to source and modify another set.
Second choice is to just use Glen's kit. I mean really, how often do I think I'd need to change discs!



1980 TR8 - MBT-RX, Overdrive Plus, GM-D9605, GS62, TS-SW2502S4 (2X), Glenn's Wilwood kit, Ted's everything else.
2006 XC90 V8 - AVH3300NEX, PDX-F4 (2X), PDX-M12, GB10, GB25, AR6K, GB12D4 (2X), Craven, IPD.
2008 328xi - AVH7800BT, GM-D8604, GM-D9605, MT230, GB40, XE 200, Primo 12"
2011 XC60 T6 RD - She won't let me.

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