Carburetors and Design

[Chris Aho]

Just your thoughts...

Would one get massacred in design if they were to employ the use of a carb? If you can back it up with being simple, etc. and having a good reason for not going with FI?

I know they are crude and inefficient when compared to FI, but they also have their advantages.

[Chris Aho]

Just your thoughts...

Would one get massacred in design if they were to employ the use of a carb? If you can back it up with being simple, etc. and having a good reason for not going with FI?

I know they are crude and inefficient when compared to FI, but they also have their advantages.

[Brett Neale]

As with all design judging questions, most of it depends on how you justify your decision. There's plenty of good reasons to choose a carb over an EFI setup:

- Cost
- Less reliance on complex/expensive ECMs
- Potentially more reliable (god knows I hate non-factory SYNC sensor headaches... argh!)
- Simple
- Probably easy to tune
- Throttle setup and idle bypasses already designed, easily adjusted

Of course the downsides are that your fuel usage may increase, and the fact that your restrictor would suck fuel AND air which decreases the power limit from the 20mm hole. But hey, if you save $2k on fuel system and ECM then spend that on shocks and tyres, get the car out on track earlier due to less electrical/fuel gremlins and tune the thing to hell, then I'm sure judges will be very supportive of your decision.

[Diablo_niterider]

i like the sound of that
plus u save a lot of weigth on fuel rail + injectors + injector seats on ur airbox + its mountings etc etc...


- Cost
- Less reliance on complex/expensive ECMs
- Potentially more reliable (god knows I hate non-factory SYNC sensor headaches... argh!)
- Simple
- Probably easy to tune
- Throttle setup and idle bypasses already designed, easily adjusted(as our friend mentioned above)

+ weigth V/S diff in lap times

seriously would love to see someone try it out
run with efi once and then with the Carb



Hiren Patel
Tech Head - Powertrain
www.orion-racing.com
K.J.Somaiya coll .of Engg. ,Bombay
+91-9820399224

[exFSAE]

I recall a senior judge talking to us last year, giving us some feedback after our design event. While he was a fan of simple, reliable powertrain setups.. his impression was the powertrain judges wanted to see lots of technical development. Fancy electronics and control systems, forced induction, etc.

Don't be designing your car around the design event though. Design it around driving. If you're going to gain something by running a carb setup, then do it. Maybe if you're a new-ish team or super strapped for cash and development or tuning time.

But even then.. you can run something like the F4i with the stock ECU and maybe a Power Commander strapped on it. Its simple, it works, and it gives you SOME tuning option plus the hardware is there (engine, injectors, etc) for future engine management if you want it.

[Superfast Matt McCoy]

I don't remember seeing an abundance of fancy engine electronics, control systems, or turbochargers in design finals. It always comes down to: does it make the car better and can you prove it? I think you would have a really really hard time convincing the design judges that a carburetor is the better option. Maybe it's just me and my belief that carburetors are the fuel systems of Satan. Of the benefits listed above, I would give you Cost, but I absolutely don't think it is worth the trade-off.

Carbs are such old technology. Can you imagine if there was a major racing series that still used carburetors? They might as well just use pushrod engines and a solid rear axle. That would just be loony...

[vreihen]

Superfast Matt McCoy said:
<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Can you imagine if there was a major racing series that still used carburetors? They might as well just use pushrod engines and a solid rear axle. That would just be loony... </div></BLOCKQUOTE>

No, that would be called NASCAR!!!!!

[James Waltman]

Cal Poly SLO at FSAE West in 2006:


It fit pretty well with the theme of the back half of that car.

[exFSAE]

<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">I don't remember seeing an abundance of fancy engine electronics, control systems, or turbochargers in design finals. It always comes down to: does it make the car better and can you prove it? </div></BLOCKQUOTE>

I'm just tellin ya what the judge said. I would imagine the cars in design finals had well tuned and setup engine packages.

In any event, like I said, don't focus on the design event. Focus on building a car that's fast, reliable, drivable, and can be built quickly enough to test.

If that means going carb'd to get a car done quick and on budget? Awesome. Do it. To hell with what the judges say, you got a car that holds together you will finish top 40 or 30.

EFI gives you more tuning options, more to learn, and if you do standalone or home built it gives you car control options down the road.

I just think its easier these days to do EFI. There's heaps of F4i and RR motors around. Not sure how long ago they discontinued the F4. Stock ECU, Power Commander, and you'll be set.

Bottom line. If you design a car with trick stuff, just to be trick (titanium flexures, active suspension, carbon everything, monocoques, etc).. it won't do you any good. It's really not that complicated to do some legit engineering and make a fast, reliable car. And if you understand how and why.. you'll not only perform well on the track but will be able to do well in judging. That's my feeling at least.

[Go Hawks]

Not quite the entire back half of that car James. Notice the carbon wheels and brakes We ended up in the design semifinals with the carb too.