any tips for making cheap sporty cars?
Galt Motors, excelence since 1945
(PS, Galt automotive is still Galt motors, i use it interchangably)
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Dragawn wrote:Some additional pointers that Strop hasn't pointed out:
- A high throttle response can give a nice boost to sportiness, although decreasing driveability, you don't necessarily need to go with more throttle bodies, ignition timing, cam profile, fuel mixture and compression influence it aswell.
- Get your handling line to match the red as much as possible, doing this may require experimenting with tyre sizes, if different tyre sizes front/back are acceptable. This will result in a very "neutral" handling car.
- Pay attention to your high speed handling, it is worth sacrificing some fuel economy over some light aero to help balance oversteer/understeer at speed.
- Small MR(/RR) cars are a viable option, they're generally cheaper to make due to just...being smaller and more lightweight.
- FF is a good option aswell, although they have gotten some flak, they are more driveable, and have the power on the axle that carries the most weight = more traction, you can also make use of torsion beam on the rear axle then, saving money and weight whilst being practical if you so desire.
- Don't spend money on a LSD if your car cant make use of it. If you don't have wheelspin, putting a LSD in is a waste of money.
- In my opinion turbos aren't worth it as of now. They're great if you can't afford to make another engine family, but with the current lack of tech for them in Automation, they're laggy unresponsive beasts that will ruin your driveability, and make you choose between either performance or economy.
- If you can afford the engineering, VVL is a lifesaver. It enables you to both make an economical and powerful, responsive engine with only a small sacrifice in the form of the octane number rising.
- Later on Direct Injection may not be the answer, DI is expensive, opting for MPFI instead can save you some money that can be well spent elsewhere.
Dragawn wrote:Some additional pointers that Strop hasn't pointed out:
- A high throttle response can give a nice boost to sportiness, although decreasing driveability, you don't necessarily need to go with more throttle bodies, ignition timing, cam profile, fuel mixture and compression influence it aswell.
Absolutely, do check the difference between a single, twin or throttle per cylinder setup because it's simply not worth it if your engine doesn't have the prerequisite performance. It may give you a tiny boost in throttle responsiveness but may end up costing way more for no gain in actual output.
.- Small MR(/RR) cars are a viable option, they're generally cheaper to make due to just...being smaller and more lightweight.
But engineering and service costs of MR are relatively higher (though I can't actually tell you by how much). Anybody got a figure?
.- FF is a good option aswell, although they have gotten some flak, they are more driveable, and have the power on the axle that carries the most weight = more traction, you can also make use of torsion beam on the rear axle then, saving money and weight whilst being practical if you so desire.
This is an excellent compromise but if you want an engine that's putting out more than, say, 300hp per ton you should start to reconsider your options if you're not using some high quality tyres.
.- In my opinion turbos aren't worth it as of now. They're great if you can't afford to make another engine family, but with the current lack of tech for them in Automation, they're laggy unresponsive beasts that will ruin your driveability, and make you choose between either performance or economy.
nnnnnnnnnnnnnnot necessarily. I agree that turbos do cost you too much drivability and a bit of throttle response, and are ancient tech compared with what's coming up, but do have their place. If your turbo isn't excessively large, and you balance the compressor, turbine and A:R, and don't go too nuts with the boost (like not too much more than 1 bar), you can achieve some great performance (this is after all how I made my 50mpg hypercar for the 2020 challenge, as well as my 40mpg budget GTi for the 90s city eco challenge). Certainly it's possible to achieve a balance of power and eco that you will never attain with an NA with similar output. However you must use the right displacement and cylinders for the car you're planning to build, and you will lose some reliability. All in all, I feel that turbos potentially hit a sweet spot but you do have to know what you're doing and it's a fairly steep learning curve.
.- If you can afford the engineering, VVL is a lifesaver. It enables you to both make an economical and powerful, responsive engine with only a small sacrifice in the form of the octane number rising.
The main downside to this is that it will make your block a good 20-25% heavier, but if you care about MPG nearly as much as you care about max power, this is 100% the way to go.
.- Later on Direct Injection may not be the answer, DI is expensive, opting for MPFI instead can save you some money that can be well spent elsewhere.
Note however that DI becomes relatively cheaper compared to the entire cost of the car as the years advance, such that by 2016 it's actually fairly standard to use DI. The advantages it affords you in how much octane you need, overall power, economy etc. is massive. But only after 2012 or so.
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