Vendor Redwood Motorsports Presents: AP Racing Radi-Cal II Road&Track Crossover Big Brake Kits!!!

[RedwoodMotors]

Redwood Motorsports is proud to present, the AP Racing Radi-Cal II crossover Road&Track Big Brake Kit!

AP Racing Radi-CAL - Road & Track BBK



As we all know, the Model 3 Performance brakes (and even worse off the standard RWD and DM brakes) are not up to the task of stopping the Model 3 consistently. The thin 25mm rotor and poor rotor design (pillar-style vanes) creates a situation where the rotor temps spike very quickly, causing quick brake fade and a dangerous lack of brakes. The mechanical stopping power with the stock low-friction pads, small-diameter rotors, and non-slotted disc faces leaves a marginal pedal feel and low-initial bite for a less-than-reactive brake pedal.

The Radi-Cal II Road & Track BBK completely eliminates all issues with the stock brakes, while providing consistent braking, good initial bite, and massive cooling to give a streetable braking package that is not shy on the track or aggressive back-roads. For a car that is this lightning-fast, we feel the Model 3 deserves the ability to stop just as quickly as it can accelerate. Eye-popping braking is the goal here, and the Radi-Cal II Road & Track Big Brake Kit delivers!

Kit Features:

• AP Radi-Cal II Ultra-Stiff Painted Calipers (Available in Red, Black, and Silver)
• AP Racing Massive 380x36 J-Hook Floating Directional Curved Vane Discs - with Anti-Squeal Clips
• Low NVH Due to Pad Tension Springs, Anti-Rattle Floating Hardware, etc. for an OE Daily Driving Experience
• Large-Depth Brake Pads (70mm tall vs OEM 50mm) for Increased Mechanical Torque, Heat Absorption, and Pad Life
• Calipers Contain Dust Boots for Added Durability for Use in Poor Weather Conditions
• Stainless Brake Lines Included!
• Ferodo DS2500 Pads Included!
• *Fits behind OEM 20" wheel without a wheel spacer (other wheels please use caliper template on our product page to ensure fitment)

These kits are currently IN STOCK and ready to ship! First come first serve, limited quantities available. We do not expect the first run to last long.



To order please visit the Following Link -> AP Racing Radi-CAL - Road & Track BBK

 

[Clivew]

What are weights for the full kit compared to the standard set-up, and is there any increased pad/disc drag which reduces the efficiency of the car? Thankyou.

At 11mm thicker and much bigger diameter, with those amount of internal vanes, 72?, the thermal managment will be excellent!

They look great by the way. (Form and function)

 

[RedwoodMotors]

What are weights for the full kit compared to the standard set-up, and is there any increased pad/disc drag which reduces the efficiency of the car? Thankyou.

At 11mm thicker and much bigger diameter, with those amount of internal vanes, 72?, the thermal managment will be excellent!

They look great by the way. (Form and function)

Thanks for the kind words! We've been excited about these as well.

These calipers are slightly heavier than the stock performance calipers (but not by much considering the massive size and retaining dust boots and anti squeal tension clips, etc.). +0.2lbs difference vs stock Performance calipers.

The rotors are a bit heavier (as to be expected) but not unreasonably so for a 4000lb car. The total assembly is +7.7lbs heavier, but to be honest for the heat management you get out of them that's not bad at all, and the stock brakes are quite undersized for the performance of the car.

For a lighter fare... take look at the competition version (only available in Military Hard Anodize Gray) AP Racing Radi-CAL which is a street-able race caliper (-3.4lbs vs the stock Performance caliper), and a lighter rotor than the "Road & Track" kit (-0.1lbs over stock) with massive cooling as well with and even higher 84 vane count for maximum cooling. We have a separate thread going for the "Competition" and "Competition Plus" kits HERE -> Vendor - Redwood Motorsports Presents: AP Racing 'Competition' and 'Competition Plus' Radi-Cal Big Brake Kit!

 

[Clivew]

Thanks for your reply. To be honest that’s an impressive weight, considering the big difference in disc width, diameter and internal vanes. The standard discs IMO are extremely thin with a cheap/poor design for such a heavy car, even with regen.

Do you have any data on differences in efficiency compared to the standard set-up?

 

[RedwoodMotors]

We'd need to gather more data for that... it's not something we've tested to date back to back. Also dependent on what wheels you're using etc. It should not have a large effect but may have a minimal range effect. If you're looking to maximize range, the base car with aero covers is hard to beat.

 

[Clivew]

It’s not that I want to maximise range, I have a P3D with 20” rims and PS4S tyres, it’s that I don’t really want to lose any more than I have now. So, any upgrades to allow hard track work need to be carefully thought out, using the right components, so as to not increase drag. Upgrades on an ICE car are fairly straight forward, with an EV, it’s more of a challenge!

 

[Orwell]

It’s not that I want to maximise range, I have a P3D with 20” rims and PS4S tyres, it’s that I don’t really want to lose any more than I have now. So, any upgrades to allow hard track work need to be carefully thought out, using the right components, so as to not increase drag. Upgrades on an ICE car are fairly straight forward, with an EV, it’s more of a challenge!

Might consider a carbon ceramic brake upgrade. Increased braking performance without increasing rotating mass and increasing unsprung weight. And lighter wallet too!

 

[Clivew]

Might consider a carbon ceramic brake upgrade. Increased braking performance without increasing rotating mass and increasing unsprung weight. And lighter wallet too!

Rotating mass will have a negligible affect on range. I'm more worried about aero drag of the disc, and friction drag of the pads to disc.

 

[RedwoodMotors]

Rotating mass will have a negligible affect on range. I'm more worried about aero drag of the disc, and friction drag of the pads to disc.

The aero drag of the disc itself will have no impact on range or efficiency. The Competition and Competition Plus version of this kit has anti-knockback springs which would have a minimal effect on pad drag, but the Radi-Cal II calipers "Road & Track" Kit does not have internal anti-knockback springs, so... no penalty for range there

 

[beastmode13]

@RedwoodMotors A few questions that I hope you could address.

1. P3 caliper has four 42mm diameter pistons. This translate to 55.4cm^2 of pistons area. All three AP caliper you offer have piston area of 50.1cm^2, which is ~10% smaller than stock. How does this translate to brake force, pedal feel and front/rear bias?
2. CP9660 and CP9668 by adding the anti-squeal clip and remove the anti-knock spring, would this make it more streetable? Comparable to CP9561? If not, what other factor drives the NVH? AP sales different force of anti-knock springs, so this implies this part is user serviceable.

Looking forward to your response. Thanks.

 

[MasterC17]

@RedwoodMotors A few questions that I hope you could address.

1. P3 caliper has four 42mm diameter pistons. This translate to 55.4cm^2 of pistons area. All three AP caliper you offer have piston area of 50.1cm^2, which is ~10% smaller than stock. How does this translate to brake force, pedal feel and front/rear bias?
2. CP9660 and CP9668 by adding the anti-squeal clip and remove the anti-knock spring, would this make it more streetable? Comparable to CP9561? If not, what other factor drives the NVH? AP sales different force of anti-knock springs, so this implies this part is user serviceable.

Looking forward to your response. Thanks.

I believe the smaller piston area is offset by the larger diameter of the rotor.

FWIW, when I was running the S calipers with 44mm pistons and a track-pad in the front with a stock pad in the rear, this theoretically shifted the bias forward ~10%+, but it didn't change feel (or performance) in any negative way. I think the ABS is designed to compensate for these changes reasonably well.

 

[RedwoodMotors]

Fantastic questions and thank you for asking!

1. This does not significantly change pedal feel, if anything *slightly* less effort than stock for the same braking force. The factory has a very conservative amount of rear bias, performance brake kits typically add a slight amount of rear bias to increase performance/decrease stopping distance. We do this with all of our NSX, RX7, S2000 kits with fantastic results on the street but especially on track, and have quite a few 1st place National SCCA and NASA wins under our belt with our sister company SakeBomb Garage.

2. That's correct if you add the pad tension springs (and remove the internal anti-knockback springs) you'll have the same NVH and range as the Street oriented "Road & Track" Radi-Cal II caliper. Obviously without the dust boots, but we run many cars without dust boots as street/track crossover kits, with zero issues as the pistons are Stainless Steel. The nice thing about the CP9660/8 (my personal favorite calipers) are that they are much lighter than stock.

 

[RedwoodMotors]

I believe the smaller piston area is offset by the larger diameter of the rotor.

FWIW, when I was running the S calipers with 44mm pistons and a track-pad in the front with a stock pad in the rear, this theoretically shifted the bias forward ~10%+, but it didn't change feel (or performance) in any negative way. I think the ABS is designed to compensate for these changes reasonably well.

That's correct, modern ABS units are very sophisticated and can compensate in real time monitoring wheel slip vs relying on mechanical prop valves like old mid 90's units. Now that's not to say you can or should throw any arbitrary piston size at the car, but as long as you are not too far off from stock bias numbers you will not change brake feel/operation. Certain piston size changes are specifically desirable to obtain better braking than the factory etc.

 

[Clivew]

We'd need to gather more data for that... it's not something we've tested to date back to back.

The aero drag of the disc itself will have no impact on range or efficiency.

Ok, but with no testing, how can you definitively say this? A wider disc with curved vanes, which acts like a centrifugal fan, creates aero drag as an inherent product of its design. The friction of the air passing through the vanes in the centre of the disc allows heat conduction from the disc to the air, and it is accelerated out of the perimeter. This whole process creates drag.

 

[RedwoodMotors]

Ok, but with no testing, how can you definitively say this? A wider disc with curved vanes, which acts like a centrifugal fan, creates aero drag as an inherent product of its design. The friction of the air passing through the vanes in the centre of the disc allows heat conduction from the disc to the air, and it is accelerated out of the perimeter. This whole process creates drag.

We're talking extremely minuscule amounts of drag here from the displaced air going through the rotors. Aero covers would have a much larger effect. If the goal is to hyper-mile you wouldn't want bigger brakes anyway. To re-state our previous comment, let's not say it has zero effect, but the effect is very small. It's not that we have not tested... it's that we have not found a measurable change in range.

 

[Clivew]

We're talking extremely minuscule amounts of drag here from the displaced air going through the rotors. Aero covers would have a much larger effect. If the goal is to hyper-mile you wouldn't want bigger brakes anyway. To re-state our previous comment, let's not say it has zero effect, but the effect is very small. It's not that we have not tested... it's that we have not found a measurable change in range.

So, have you tested, or not tested? First you said you haven't now you said you have?

I have a Model 3 Performance, and will use the car hard on track, but it's still my daily driver. Just because I don't use 18" wheels and aero covers doesn't mean I want to throw away efficiency by fitting untested products to my car. I'm sure there are plenty of others in the same situation.

It's easy to write throw away comments like 'it won't affect efficiency' but once paid for and fitted to the car and I find I lose 5%, it's too late.

And in regards to your quoted 'miniscule amounts of drag' Have you calculated this, or are you a qualified aerodynamicist or engineer?

 

[Mash]

They were extremely polite considering your tone... And even tried to help. They said that they did not test and won't test aero drag of brakes. Because it's stupid. Primitive knowledge of physics says that it will be immeasurable. You should try and go harass Essex who designed this kit. But you will get the same answer anyway.

So, have you tested, or not tested? First you said you haven't now you said you have?

I have a Model 3 Performance, and will use the car hard on track, but it's still my daily driver. Just because I don't use 18" wheels and aero covers doesn't mean I want to throw away efficiency by fitting untested products to my car. I'm sure there are plenty of others in the same situation.

It's easy to write throw away comments like 'it won't affect efficiency' but once paid for and fitted to the car and I find I lose 5%, it's too late.

And in regards to your quoted 'miniscule amounts of drag' Have you calculated this, or are you a qualified aerodynamicist or engineer?

 

[Clivew]

They were extremely polite considering your tone... And even tried to help. They said that they did not test and won't test aero drag of brakes. Because it's stupid. Primitive knowledge of physics says that it will be immeasurable. You should try and go harass Essex who designed this kit. But you will get the same answer anyway.

If I’m looking to spend circa $5000 on brakes, I’d like answers to important questions such as range loss. I would absolutely hope they try to help!

If someone gives me conflicting info, one minute saying they haven’t tested, and the next, they have, it raises my suspicions of what is the truth.

If you come onto a public forum selling performance products, you should expect many questions, especially when the car is an EV. If you think that is harassment, then you are very sensitive.

I’m asking if they are qualified engineers in regards to technical question etc, because that makes a difference to me, compared to being an unqualified salesman.

 

[Mash]

If I’m looking to spend circa $5000 on brakes, I’d like answers to important questions such as range loss. I would absolutely hope they try to help!

If someone gives me conflicting info, one minute saying they haven’t tested, and the next, they have, it raises my suspicions of what is the truth.

If you come onto a public forum selling performance products, you should expect many questions, especially when the car is an EV. If you think that is harassment, then you are very sensitive.

I’m asking if they are qualified engineers in regards to technical question etc, because that makes a difference to me, compared to being an unqualified salesman.

You got your answers many times:
1. It can't physically change drag above margin of error.
2. They didn't test.
3. They not going to test, because #1.
4. They didn't notice any range drop after kit without anti knockback springs installation.
5. You can ask those who designed the kit - Essex or even AP.

Nobody said anything contradicting, you're just not reading answers, because you're busy "fighting for justice". And they just too polite to stop your harassment.

I'm out, sorry for offtopic.

 

[Clivew]

Yeah, lot’s of answers, but no proof from testing. And that is the crux of it.

Ventilation drag is what causes most of the range loss due to the wheel design, aero cover off or on etc.

Ventilation drag is due to the high pressure air moving from inside the wheel/wheel arch, through the wheel spokes to the outside low pressure area.

The diameter and width of the disc brake, and the change in the internal ventilation design from pillar (standard) to curved vane, increases pumping losses a lot (thus why the curved vane type is so much better at disc cooling), and aero drag is increased with pumping losses. Also, the change in turbulence and the amount of turbulence in this area changes the amount of ventilation drag through the wheel. These are the facts.

Unless you have carried out testing to KNOW if there are negligible losses or not, saying so is disingenuous at best, arrogant at worst.

Fighting for justice? More like fighting for facts as a potential customer.