22

tl;dr: different gear ratios are a feature, not a bug. Some cars use more gears for acceleration, some use them for better gas mileage. You can't do both. At 3300-3500 RPMs, shouldn't the WRX be able to achieve better gas mileage by keeping the same 5-speed gear ratios, while adding an additional gear to lower RPMs to 2800-3000? You've exposed the ...


15

Reverse is pretty equivalent to first gear, for a ratio of around 3.2ish. If it were any lower, it would be difficult to get started from a stop since the torque just won't be there. If you've ever driven a stick-shift, try starting from a stop in 2nd or 3rd gear and you'll see what I mean. For example - ratios for my manual 5-speed 2007 Mazda6: 1st: 3....


13

The answer is no because you mention being limited by your redline. Regardless of power, a certain RPM will result in a certain speed for a given gearing. Chances are the gear ratios were chosen based on the factory output of the engine. However, for other cars this may not be the case. Because of wind resistance (in many cases) a vehicle may not have ...


11

Summarized Answer No, HP does not determine MPH in a gear, the gear ratio does. Although there are hypothetical ways that HP can seem to make the vehicle go faster in the same gear, it doesn't actually change the speed capacity of that gear as long as the engine RPM is limited. Expanded Answer As noted, the answer is no... or at least not really. In ...


8

Well the simple answer is (as you suspect)... No. With fixed gearing, you are going to be doing the exact same speed at any given engine RPM with 100bhp or 600bhp.


8

It is in fact true that driving at slightly (key word) higher rpms is much better (for both fuel efficiency and engine life. The rpm range for the two can be different). Part 1. Engine life: Every engine has a least resonant rpm. This is when your engine vibrates the least (Think of this as the opposite of that point when your entire car begins to shake ...


7

Most vehicles will only have a single overdrive, where the second to the last gear will be a 1:1 ratio (or something near it). The notable thing here is the Tremec 6-speed transmissions (used in the Camaro, Viper, Corvette, Mustang, and others) which have the double overdrive. The main purpose of more gears is to allow the vehicle to stay in the torque/hp ...


7

It depends what you're trying to optimize. If you're looking for optimal acceleration, more RPMs are better. Most engines today produce peak power at redline. As for optimal efficiency, there's two parts to that as well: Turning fuel into mechanical energy as efficiently as possible, and using the least amount of fuel to cover a distance. The engine ...


6

One important factor is the mass of the components. Smaller, lighter components and shorter strokes allow higher RPMs. Given equal RPMs, an engine with a bigger stroke will put higher stresses on the components, which means they need to be stronger, which means they need to be heavier, which increases the stress even more. Motorcycle engines tend to have ...


6

Your question is incredibly board because it can be broken into 5 distinct aspects; planetary gear sets operation, clutch and band operation, torque converter operation, control system operation and the power flow through the transmission. Further complicating the answer is that there are hundreds of different types, kinds and transmission manufacturers. For ...


3

The amount of acceleration you feel depends on the amount of power the engine can deliver, and the speed you're driving at. Power Internal combustion engines are more efficient at some speeds than others. To illustrate, here's a random power and torque curve: Torque (which is the property you feel when you accelerate) peaks around 3000 rpm, and then ...


3

First the bicycle example: resistance is acceleration essentially. If you feel it, you accelerate. You can spin your pedal only so fast, so after some time, you can no longer increase the speed of your pedals, and thus the speed of the bike, that's the time when your efficiency dropped, and you need to shift. Now the cars: Similar concept applies to car ...


2

In most sport-oriented (and heavy towing) vehicles, the point of an extra transmission gear is to keep the engine operating between it's torque peak and HP peak. Thus, most models of vehicles that are base models will have a 5 speed manual (or 3 speed auto), while the sportier or heavy duty versions will have more gears to chose from. Many 6 speed ...


2

If the transmission is slipping now a rebuild will give you a slight gain in mpg. If you have the optional towing differential with a 3.92 ratio then changing to the standard 3.55 will also yield a small gain. This will hurt acceleration though, while increasing highway mileage. The biggest issue is "cost to benefit" ratio and the time to recoup those costs ...


2

Your Carburettor might be clogged. Clean it along with the air filter and you should be good to go. Also check if your "choke" chord is not faulty since it will tend to send a rich mixture to the engine which will stall it at low RPM and you get that "Missing" feeling but more importantly your fuel efficiency is affected.


2

Let's forget the power for a while. The body of your question shows that you're in fact interested in this: can a custom air intake influence the exact RPMs at which you "redline"? Well... yes, sort of. That depends on rev limiter. Some are of "soft-cut" type, which means they have an RPM range where they act, not a single red line. In the operating range ...


2

When a rear wheel drive car makes 1 tire revolution while driving how many revolutions does your drive shaft make? It depends on the gearing in the differential. If the gear ratio is 3.42:1, the driveshaft will make 3.42 turns for every 1 turn of the wheel. Are driveshafts mistaken as an off balanced tire if they are near the same ratio? It could be, ...


1

To add to other answers, the only time extra horsepower will increase speed in a given gear is for top gear, as often the maximum speed is where the engine runs out of power to overcome rolling/air resistance and the car does not reach the redline in top gear no matter how hard you push. Extra power will allow more of the rev range to be usable. Example - ...


1

The bellhousing and everything else perfectly fits, and the drive is smooth. what I am not sure is the nitty gritty like the size of the clutch.


Only top voted, non community-wiki answers of a minimum length are eligible