Question: What's up with the weird-looking rotors on the '09 ZR1?
No Name Given
Via the Internet
Answer: Like many other high-end exotics, the ZR1 is equipped with carbon-ceramic rotors similar to the ones used in modern race cars. This composite material consists of carbon-fiber, graphite, resin, and silicone, yielding a lightweight and very durable rotor that rarely needs to be replaced.
There are a few negatives that come along with this type of material, chief among them cost. A single carbon-ceramic rotor starts at $1,695-significantly more than a comparably sized conventional unit. The other drawback is that you need to build up heat in the rotor in order to get maximum performance.
That being said, if you want race-car-quality stopping power from your car's braking system, and you have a few thousand dollars lying around, a set of aftermarket carbon-ceramic rotors could be just the thing.
Question:I remember the '70s, when we switched from leaded fuels to unleaded fuels and gasohol. I also remember the problems we faced having older cars. In recent days I've been having dj vu, since the only fuels available contain ethanol. Everyone is talking about the benefits of these fuels, but are we going to see the same problems with our older cars as we did back in the day?
Marty
Via the Internet
Answer: There is indeed a push to increase the use of ethanol as a means to reduce fuel-related emissions and lessen our dependence on foreign oil. The bad news for the vintage-muscle car owner is that ethanol can act as a cleaner that loosens the sludge, varnish, and dirt that accumulate in a fuel tank. Once loosened, this material can stop up the fuel filter and cause an older tank to leak.
Ethanol also absorbs moisture in the fuel tank. In a car that is not driven every day, the ethanol-water mixture may separate from blended gasoline and sink to the bottom of the tank, where the fuel pickup is located. When the car is started, this mixture may clog fuel lines and block carburetor jets. It may also be incompatible with older cork or rubber compounds as well as some metals.
Ethanol also runs leaner than gasoline, so you'll need to perform some modifications to correct this. As the level of ethanol or other alcohols isincreased, the fuel efficiency of the engine will decrease. This is because gasoline has more energy per gallon than ethanol-based fuel.
An engine running on ethanol-based fuel runs at a richer air/fuel ratio than an engine running on gasoline. The stoichiometric-or chemically ideal-air/fuel mixture for an engine running on gasoline is 14.7:1; for an engine running on E85 (85 percent ethanol, plus 15 percent gasoline), the ratio is 10:1. However, if converted correctly, an E85 engine will have performance equivalent to, if not greater than, the same powerplant burning gasoline. This is because ethanol has a higher octane rating, so it can withstand much greater compression ratios as well as advanced timing.
A modern-day muscle car with computer controls should make the air/fuel-mixture adjustments needed so the engine runs its best with whatever blend of gasoline you use. Still, when switching to an alternative fuel, you may notice erratic performance or a "Check Engine" light for several miles until the computer has a chance to adapt to the change.
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