GenII Brake Upgrade w/o breaking the bank?

haven't you seen the pix of several cars that were used for different types of racing? maybe they never did hit the track but they looked kinda cool...

 

I say have fun. I too like to tinker as a hobby. I personally look for return on investment when I tinker but thats just me. That's why I built this (for fun). Now my Prius is my gas guzzler.

 

Lol. Yeah, that's what people think. I don't think I could make it thru airport security with this bike.

Yes they are battery packs. I have 16 Headway 40152S batteries connected to make a 24V/30ah battery pack. It is a very robust pack for an ebike. It is good for about 20-25 miles of all electric range (when fully charged and ran down to min (which I've only done once). My normal round trip commute is 17 miles (to work, to the gym then back home). When I get home I usually have about 40% SOC left (I usually only charge it to 80%). It will go about 25mph on a flat road w/ no wind and me crouched in an aerodynamic position. Its really fun to ride and a great conversation piece. Chicks dig it.!!!!!!

It was really fun to build and like you, it met my hobby needs. Now I commute w/ it as much as possible. I'm not sure what the eMPG is but I'm guessing about 500mpg's (just a guess).

I appreciate reading about all the mods you do. Some people put 572's in a 72 Nova, others plasti dip their grille and emblems. If it makes you happy, then its worth it.

Here is the next bike I'm going to mod (into an ebike) (better aerodynamics).

 

I see you have ordinary brakes on there, does it regen as well if not why not "got to improve the range".

 

Lol. Yeah, it is getting off topic but in a fun way (for me anyway).

The motor is a 24vdc/500W Currie motor (.667 horsepower max). It came off of my son's electric scooter that was sitting in our garage. The scooter was a Schwinn S500. If I really wanted to do it right, I would have put a 36V 1000W (1.33333 hp) and 24 cells for a 36V/30ah battery pack. That would probably net me around 30mph.

Here's a better pic of the motor and associated mech linkage/mounting (hose clamps, ubolts and eye bolts work wonders). This is my "prototype" or "proof of concept" bike. I have a front freewheel so the motor can turn the front sprocket w/out turning the pedals but you can still pedal if you want to (or if the batts dead). It was really fun to make. A lot of time spent staring at the bike in the garage. I can also still shift gears (front and back) to run the motor at its most efficient rpm for the speed.

 

Yeah just ordinary brakes. The ROI on regen is counter productive since my commute doesn't require it and it puts drag on the bike when coasting. Additionally, I can charge at work if necessary. I did consider it though.

 

Any car can be turned into a full race car, just look at the 24h of Lemons series. Some require more modification than others for such a purpose... but that's not the point.

I'm not seeing any "testing the boundaries" of these cars here... one hits the boundaries when the car spins, when the brakes fade, when the engine overheats. One nears the boundaries when the car goes up on two or three wheels around a hard corner. I've yet to hear a story like that here.

It's cool that you folks are trying out various mods on your cars, at least you're poking your nose under the hood, and maybe even turning a wrench once in a while. But until the car gets pushed, you're not really going to learn how you're changing the car's dynamics, be it for the good or bad...

 

that stuff is all cool, but how much does it weigh? i don't think its gonna be a good idea to add larger rotors (maybe a little is ok) and then on top you got probably heavier wheels and tires (almost no 16" touring models in the mid-atlantic. Wth up with that?); definitely w/ that 13" rotor and probably w/ the 12.44" too. some powder coated alloy calipers would be sweet, but bigger wheels, tires, brackets and rotors will kill what little acceleration these cars have. and how will the brake electronics handle it? will a larger master cyl be required? how will all this affect the entire brake and hybrid systems?
it sure would look bad @$$ though!

 

What would concern me, is a brake upgrade in the front, without any improvement in the rear, may cause significant weight transfer.

My worry is that the rear tires would easily lose traction, especially if someone was braking while turning at a high rate of speed (like someone trail braking Trail braking - Wikipedia, the free encyclopedia) - may cause the rear end to slide out - although if the skid was manageable you'd possibly get some awesome 4-wheel drift... but in everyday driving if the skid is'nt manageable you'll probably end up hitting a tree... or an old honda civic with a baby in the back seat...

I’m not saying don’t do it, I’m saying, please, please, please make sure you know what you’re doing!
I don’t want to see anyone get hurt or their Prius get damaged.

As much fun is it is to drive fast, you also have to safely stop and maintain control of the vehicle.

I’ve had to do some emergency straight line braking from 90+ mph and felt the rear end dance a bit from the weight transfer. Maybe the rear end dance was due to my worn out springs and struts allowing the front end to dive. Perhaps a lowered suspension with stiffer springs would avoid the significant weight transfer and the larger brakes could improve braking.

Good luck with your project and please keep us informed what advantages or disadvantages this modification caused. It completely sounds like a cool concept and I hope it’s awesome in application.

Here's a video that's off topic, but thought you'd like. (I wish my prius drove like this! but Sadly never will...)

 

A brake proportioning valve could fix this...

Hey, Justdidit, if you'd take advice from a random stranger, let me recommend this. A little cross-pollination if you will... go check out some other forums where people are doing real tuning on cars that see real action (i.e. SCCA or NASA sanctioned racing). Read through build threads and see what people to do prepare cars that really get pushed.

Also, check out some local tuning / racing shops and check out what's being built. Talk with the guys there about your ideas. Ask what some of the common pitfalls are for various projects, such as brake and suspension mods.

I get the impression that you're just throwing spaghetti at a wall and seeing what sticks. But as Dave points out, there can be consequences (besides wasting money) to such actions. Your "R&D" could greatly benefit if you build off the experiences of others.

You guys can call me the "anti-modder" all you like, but on a site where folks proudly proclaim they've modded their Prius with a headlight bulb upgrade, a window guard addition, and "improved seat tilt", you're not going to see much in the way of real projects.

 

whoa!!! lets all calm down here. no throat chopping please. this is all supposed to be fun. even if y'all can't agree, at least you both have the good sense to own prii. can we all try to be polite now?

 

I don't think that was the point shovel-head was making. With bigger wheels + calipers + discs at each corner, you're going to change the handling & ride of your car. Besides the added unsprung mass, heavier wheels & discs have more rotational inertia.

Case in point, I bought a high-performance sports car off eBay that had been molested by the previous owner... he put some oversized, heavy steel wheels on the car, and as a result it drove like a cement truck. Every bump jarred the entire car, and acceleration and turn-in were both sluggish. After swapping out those wheels for some performance wheels, it handled like a go-kart.

Read more here: Unsprung mass - Wikipedia, the free encyclopedia

 

larger, heavier wheels have already been confirmed to lower mpg; add to that the weight of big rotors = even worse mpg. if you got more money than brains (don't take that personally) you can get custom rotors w/ alloy hats or ceramic rotors, such as MB SLR's use, but they're like $1200 each. i don't know how much custom racing rotors cost, but since the stock brakes have 180k on em, i bought stock replacement drilled rotors w/ ceramic pads from ebay for $105.00. if they don't squeal like a pig i'll be satisfied. i may even paint my calipers when i get it apart.