Project Nissan Sentra Spec-V Part 6: Modifying the Brake System
By Mike Kojima
When we last left off working on Project Spec-V, we were modding our engine and suspension for maximum power and road holding. Since we now have power and cornering capability, we'll turn our attention to the other important part of the performance trifecta, the brakes.
Since we are greatly increasing our engine's horsepower with turbocharging and increasing the stick in the corners with the NT01 race tire, the demands being placed on our braking system have gone up considerably. Although perfectly adequate for street use, the stock brakes were not designed for repeated applications from high speeds for extended amounts of time.
The stock brakes would be woefully inadequate for stopping the Spec-V under racing conditions, which on some tracks would mean slowing from about 150 mph down to about 40 lap after scorching lap.
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| We replaced our wimpy stock Sentra brakes with these huge 13″ Stoptech Aerorotors with ST40 calipers. These brakes dwarf the later models Brembo brakes as well. |
We called upon the experts at Stoptech to cure our brake issues. Stoptech provided us with their racing brake kit with ST40 4 piston calipers and 13” floating rotors. These huge brakes should haul us down from any anticipated speed with ease.
The stock front calipers on the Spec-V are a single piston, sliding design. The caliper is prone to flexing which can make for inconsistent pedal effort. Also, being only single piston, the pressure distribution on the pads between each side and on each pad can be uneven. Lastly, if not maintained well, it’s possible to get a stuck caliper if the slider pins get bent or corroded. This basically results in only one pad doing all the work and one pad getting all the wear. The dragging pad will also run much hotter, possibly damaging the pad, rotor and caliper. The StopTech calipers, having 4 opposed pistons have nothing to ‘stick’ or drag!
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| The ST40 caliper has a stiff forged body with this bolt in brake bridge that really stiffens things up. |
The StopTech ST-40 caliper is made of very stiff forged aluminum which improves feel and consistency, while the 4-piston design greatly improves the pressure distribution on the pads; more even pressure distribution should improve pad wear and feel consistency. Unlike most other racing brake calipers, the StopTech caliper has dust boots to protect the seals during long term street driving from abrasive pad dust, water and other potentially damaging contaminants.
4 comments
Hey guys. This build seems to be highly… outsourced. Like, HotRod PowerTV outsourced. I don’t mind that you spend some money to get these things done, or talk with experts who are highly paid when they get some things done, but some research and reporting on your decision-making might help make it look less sponsored and may help out people with a smaller budget.
In the case of B15 brakes, admittedly the single piston calipers are the WORST, as are the crappy quality rotors. Did you put any consideration into the ’04+ B15 Brembo front setup with some decent pads? What, ultimately, pushed you toward the StopTech kit? Were any other kits commercially available? Were there any kits that would address the garbage stock rear calipers with poorly-chromed pistons?
Also, possibly helpful would be published dates on your articles. I’m not sure if I’m responding to an article from 10 years ago or not here…
This is a race car, not a cheap car. We don’t care if it “looks sponsored”. Stoptech calipers are the best for stock hydraulic systems bar none due to their wide range of piston sizes. I am not sure what you are talking about when you say outsourced, there are a lot of in-house designed and fabricated parts in this car.
You sound a little defensive. I guess I’ll have to explain better?
If you watch HotRod PowerTV, it becomes pretty obvious that they aren’t actually informative shows so much as they’re paid plugs for the products showcased in each episode. In this way, the work is both sponsored, and outsourced. Bolt-ons, if you will. This isn’t to say I’m against bolt-on modifications, especially with something so critical as a braking system, but knowing more of your thought processes would be nice.
If you had a decision making process, perhaps laying it out in the article would help people reading understand what’s going on. You say “Stoptech calipers are the best for stock hydraulic systems bar none due to their wide range of piston sizes.” and two things immediately come to appear. You’ve stated one objective fact that supports your opinion (their wide range of piston sizes), and one outrageous opinion that does nothing to support your decision (best, hands-down).
If Stoptech sponsored, use journalistic integrity and disclose it. If you didn’t, and want to expand further on how you arrived at using their calipers, feel free to do so (heck, “They’re the only ones who make a kit” is even an okay answer). Do it in the article, even. The fact that you’ve “decided” in the TECH article without explaining the decision-making process doesn’t help your readers learn from the article. A good nugget here would have been a primer on brake balance and bias, and the importance of maintaining a relatively stock f/r area ratio… I appreciate your criticism of the stock, lo-perf, 1-piston calipers. They’re junk. They need to be replaced for a safe, functional car.
I’ll also reiterate: Did you consider the ’04+ Brembo systems? Should there be something I’m concerned with when *I* choose to go with the factory Brembo setup? Problems with track-day heat rejection, etc?
Did you research any systems that replaced the REALLLY BAAAD rear calipers with anything more reliable? Hell, if you’re plugging Stoptech, and they have a replacement, tell me THAT, even.
Not defensive, but I am annoyed at the journalistic integrity shots. I am pretty sure people are not interested in the extreme details of my decision-making process in this type of article, a primer on brake balance and bias is a huge digression from an article about building a car, it’s a whole new article. For an idea on how Stoptech does validation to determine proportioning read this. This too. Stoptech has 32 different piston sizes and since I didn’t want to go to a pedal box and balance bar, this is the best way to put a front brake with a significantly larger than factory Brembo front rotor and pad volume in while still maintaining proper proportioning. There is nothing outrageous about this and it’s not an opinion, its a fact. I also wanted to have a floating front rotor to reduce piston knockback and a lighter 2-piece rotor, not available with the factory Brembo stuff. I have been competing in road racing with the Sentra platform for years and the factory rear brakes are completely adequate and reliable. A FWD race car doesn’t use much rear brake and for instance, the rear pads can easily last for a couple of seasons. In my opinion, the only reason to change to a two piston race caliper on these cars would be for less weight and the abilty to choose from a wider assortment of brake pads. Or to have a more reasonable rear master cylinder size so the balance bar can be staged straighter if using a pedal box, dual master cylinders, and a balance bar. Oem single piston rear brakes can be used on pretty extreme FWD race cars. The record-breaking Spoon Civic and the all-dominating PZ Tuning Civic both use stock rear brakes.