# RE: vehicle weight, HP, and gearing comparison between vehicles

• ydeardorff
In summary, the conversation revolved around the speaker's enrollment at VRI at WWU and their independent study project of creating a V12 engine from a pair of motorcycle engines to go into a VW based kit car. The calculated power and torque output of the engine were mentioned, as well as the target of achieving Lamborghini-like acceleration. The speaker was looking for a way to compare the weight, power, and gearing of different vehicles and asked for help with calculations and formulas. The conversation also touched on an acceleration simulator and a modeling tool for engine component alignments. The engines used for the V12 were revealed to be Kawasaki Voyager and the speaker mentioned that it took them two years to develop the project.
ydeardorff
Hello all.
I am now enrolled at VRI at WWU!

I am working on a sort of independent study project. I am making a V12 out of a pair of motorcycle engines to go into a VW based kit car.

I have run the IHP formula and come out with 250hp, and 220 lb/ft of torque.

The car weighs 1800 pounds.

Ok now, onto the next. I am targeting as close to Lamborghini acceleration as I can.

What I am looking for is a way to compare the weight, power, and gearing (including final drive ratio) of one vehicle to set the gearing of the other.

I know adjustments will have to be made for the torque/hp curve peaks. but trying to get a good close ball park and start from there.

The transmission will be modular and a sequentially shifted unit.

Any one point me to the proper calculations, or formulas?

Yaughn

This acceleration simulator should help you evaluate the performance you can achieve with a given power/weight ratio, tire's friction coefficient and vehicle layout; no matter what type of engine or transmission. (the theory is at the bottom of the page)

Once you know the target vehicle' speed and the engine rpm for the desired power output, you just need to calculate the proper gear ratio to link the engine to the wheels (formula and link to nice calculator here).

Thanks! Ill look into them.

Im trying to iron out some details on the engine component alignments. There's always something to have to wriggle into place. A V12 has very little room to work with ironically.

I have something that can model this for you:

It took me about 2 years to write. Admittedly, I wasn't working on it flat out, but it's pretty involved.

What pair of motorcycle engines have you made a V12 out of?

kawasaki voyager. Its a work in process, not complete yet.

## 1. How does vehicle weight affect its performance?

The weight of a vehicle can greatly impact its performance. A heavier vehicle will generally have a slower acceleration and lower fuel efficiency compared to a lighter vehicle. It can also affect the handling and braking of the vehicle.

## 2. Does a higher horsepower always mean better performance?

Not necessarily. While horsepower does play a role in a vehicle's performance, it is not the only factor. Other aspects such as weight, gearing, and aerodynamics also contribute to a vehicle's overall performance.

## 3. How does gearing affect a vehicle's performance?

Gearing refers to the ratio of a vehicle's engine revolutions per minute (RPM) to its tire rotations per minute. A lower gear ratio results in quicker acceleration but lower top speed, while a higher gear ratio allows for a higher top speed but slower acceleration.

## 4. Is it important to consider the vehicle's weight, horsepower, and gearing when comparing performance?

Yes, all of these factors should be taken into consideration when comparing the performance of vehicles. Each one plays a role in how a vehicle accelerates, handles, and reaches its top speed.

## 5. How can I determine which vehicle has a better performance based on weight, horsepower, and gearing?

The best way to determine the performance of a vehicle is to test drive it and compare it to other vehicles in its class. However, you can also look at the vehicle's specifications and reviews from reputable sources to get an idea of its performance capabilities.

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