I'm looking to reduce as much drag and weight as possible in my drag car. I have been looking into "mini" alternators that weight about 6-10lbs. What ones have you guys used with success?

For those that have deleted the alternator all together, how did you go about doing that? Do you just run everything off the battery only, and just charge the battery in between runs? or does something need to be done?

What battery would you recommend for this? I am using the braille battery that only weight 11lbs right now. Not sure if it can take that kind of abuse?

 

I don't run one at all road racing. I used a stock adjuster pulley that I pulled off that big aluminum rack that holds the AC compressor. What I made mounts like a stock alternator and adjusts like one too.

I use a huge battery that sits as far back as it can on the floor on the passenger side. I lost 12lbs off the top of the engine over the front wheels and put the weight where I wanted it.(car needed ballast anyway) It will run a whole weekend with out a re charge(90 minutes or so). Drag racing could use a really small battery to run if you had a jumper box to get it started or topped it off between rounds.

 

you could also just get a waterpump belt small enough that you can flick onto the crank and pump, sort of key flick it on,
If you really wish to get rid of it, then run a 16v battery with the associated accuvolt system electric unit that helps regulate the voltage and then use a 16v charger and charge it between rounds

 

This will be a future project of mine as well. So far I've been planning to use one off of a sprint/firefly unless I can find something even smaller. I'll also end up making a custom underdrive pulley for it.

 

What kind of battery are you running? If you know the weight of it that would be great. And its still a 12v battery?

I was looking into the accuvolt systems, but if there's people running road racing without a battery, is it really needed? Of course after each run you would charge the battery still. The car would not be running for more than 3-4 minutes at one given time. It will also be running a very small amount of electronics. 3 small gauges and a 1st gen style ignition system. Also before and after the run, an electric water pump and small 12" electric fan. But that's just before and after the run if the cars getting hot.

 

Another thing i was thinking, which pretains to my own personal needs.

I live in Central Florida, where it barely ever gets cold. So I should not need as many CCA as others. Plus with open header, large ports, and rotaries turning over much easier than high compression piston engine, we should not need as much battery as others to have reliable starts.

Here's a few lightweight 12V batteries I have been looking at. Ranging from 9-13 pounds and from 110-160 in price.



All 2 VOLT:


http://www.batterycentralmall.com/Ba...sey/pc535.html

http://www.batterycentralmall.com/Ba...sey/pc625.html

http://www.batterycentralmall.com/Ba...pc680_Ody.html

http://www.braillebattery.com/index.php/batteries/b129/

http://www.braillebattery.com/index....teries/b14115/

 

what a lot of kids out there are doing is the subaru justy alternator. its really tiny and plugs right into the s5 wiring harness.

 

Alot of guys that don't run an alternator are using a 16v battery and charge between runs. You need stable voltage to run your ECU and ignition system.

If you run an alternator, just get a small single wire alternator. I use the first gen style. It's pretty small and light and I have it mounted on the side of the engine with race underdrive pullies. Then you can run an electric water pump that you just turn on with a switch when needed. Either an external water pump or an external motor that drives the factory style water pump. Those are your basic two options.

Obviously the 16v battery without the alternator will net the least amount of power loss, but is kind of a pain to charge between runs.

 

Kilito has a mini Alternator on his race car.. Maybe you can PM him for details

 

Is this recent because the last time I saw, he was using a 16v system without an alternator?

 

You're correct... What I saw was the motor to drive the water pump.

He had that little motor in the same location as the alternator with a belt connected to the pump... My memory is starting to play tricks on me

 

The only way I remembered is because I have the exact same setup, except I run a side mount alternator. It's the same setup most v8 guys use.

 

After literally weighing the options. Seems it's better to keep the alternator and use a light weight battery. Even a light weight "mini" alternator dosnt save any more than a few pounds. and for the cost, the money is better off spent else where.

 

good call, as with the amount of electronics we use these days its a big trust to have in a 16v battery that is constantly going flat when your in use .

Ive thought about it with my car but after having it overheat once becuase i forgot to turn on the water pump i needed all the elec power i had to turn on the fans and the water pump . I always thought if i had a 16v battery that was a bit week after a run id have no hope of keeping all the electronics going to save my donk

 

The point of a light weight alternator isn't just to shave pounds but to reduce rotating mass. Less amp draw means less resistance from the alt, but it still has to spin the shaft and windings. I doubt this is worth much power, but sometimes every little bit helps.

I agree that unless you are fighting for tenths it's hard to justify the cost, which is why I just plan to retrofit something easily found in the local bone yards.

 

I asked a few V8 guys that did some testing on this. They said that no gain was made when removing the alternator, and one guy got slower because of the power draw on just one 16v battery. They had mentioned the right way to do it is to use two 16v batteries. That would be weight gain, not loss.

Basically, an alternator dosnt have the same effect a water pump has when it comes to turning it.

 

You can also run a larger pully on the alternator to slow the rotational speed, but like mentioned, the gains is very very minimal. The amperage needed to run a race car is very minimal so the alternator is not drawing very much anyway compared to a street car that has A/C and a bunch of stereo stuff, etc.