Alternator or no alternator
Turbo Mini Forums

I was wandering do I really need an alternator? I'm building my car primarily for sprinting & hill climbing but would like to be able to use it on the odd track day occasional road test & Avon.

I have no intension to fit; headlights, heater or stereo, so do I really need an alternator?

I know Wil & Ben don't have one on the TT2, is anyone else running without one & any idea what kind of battery life I can expect without one? as an aside I'll probably be running a red top 40, over kill I know but should produce the goods.

When my alternator packed in I drove the car for at least an hour with headlights on and it was fine untill the inevitable happened. That was on a standard sized mini battery.

It'll be the continous starting and electric fans at places like Avon etc that could possibly kill it?

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1/4mile in 13.2sec @ 111 terminal on 15psi

i think itll be fine for race use, dont need to power much.

get a battery on a trolly to plug in for start ups that way you save your car battery.

no longer a series, but still 1.3 turbo.

I've thought that, but I think some racing/hillclimbs/sprints state you have to have one. Check the regs.
I agree, saves weight and drag on the engine.

Edit: if the regs say you have to, pull the guts out of it?
So theres just a pulley wheel?

Edited by Jason G on 22nd Apr, 2008.

Depends on how much electrical gubbins you have, the DON runs one but it obviously has the ECU, injectors etc to run.

fuel pumps & cooling fans must take up abit

i haven't and continuous starting has not been a problem my battery is only 35Ah i think.
mine has to run the pump, ecu and brake lights, dash etc but thats it. seems to cope fine for ages, and i mean ages.
i will however be putting one on, just so i dont have to arse about thinking to charge the battery all the time etc.

My new hillclimber doesn't have an alternator, it has 2 of the dry type racing batteries, I can't remember there serial number at the moment but I will check, there not very big but still fairly heavy 3kg ish

I think its a pain in the arse not having an alternator, bearing in mind though my car has an ECU, HP fuel pump and electric water pump, ignition system etc, all the while the car is running its draining the batteries, if the voltage drops to much it can cause misfires, you really need a slave battery to start the car, all in all a fookin pain.

As soon as I can i'm going to fit a small lightweight alternator, there are plenty available at around 2.5kg, I can then bin 1 of the race batteries and still be better off weight wise.

Graham

We don't run one as already stated, but we try to start it on the slave battery as much as possible. Remember we double drive so it gets twice the use.

There are no regs in the mod prod that state you have to have an alternator, only that the car has to be able to be started from the drivers seat, ie you have to have a battery and a starter.

The thing about an alternator and sprinting is that the car is not running that much so does it really get a chance to charge much between runs?

We have measured the current when running and it is 4 amps, so not much. Ok injectors will add to that, as will an electric water pump, but it should be fine for sprinting/hillclimbing.

It is not that much work to add one at a later date if you are struggling to keep voltage during an event.

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http://www.hillclimbandsprint.co.uk/default.asp

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Every time I go to the rollers I seem to have alternator problems and the guy who maps my car has kittens about maintaining a constant voltage for the ecu. Phil Short used to have to change batteries between practice and timed runs I seem to recall.

On 5th Sep, 2011 Vegard said:
I stand corrected. You should know

Hi,
An ECU will usualy shut down on over or undervoltage to protect itself. However it will usually compensate injector / coil charge time up to that point.
Cheers,
Gavin :)

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When the voltage gets low on mine the first thing to go is the VR sensor signal..then its game over! Lol

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1/4mile in 13.2sec @ 111 terminal on 15psi

This Sunday coming is my 1st event with the new car, I'll see how things go regarding the battery, Phil reckons the joint efforts of both batteries just about last a meeting, depending on laps etc. During my reasent test session I'm pretty sure the voltage got to a critical level, looking at the notes Phil gave me with the car voltages below 12.4v can cause a misfire, when it gets to 12v it can stop all together, fully charged output is 13ish volts

When you have a small team of helpers as Phil probably did have, connecting a slave battery etc and unplugging it just before a timed run wasn't a problem, but for me on my own, coupled with a shit memory I can see my self setting off dragging a fooking battery behind.

At the moment I'm still going to fit an alternator.

Graham.

Wow, I am supprised that it shits the bed at 12v as this is the nominal voltage fo all car equipment. Ours will run happily down to 11v, but it does not have injectors. On most events we do normally put a charge in the battery over lunch or over night with a small generator.

Any time I have seen phil short racing it was just like the rest of us, him and maybe a mate, but certainly not a big pit crew.

We have put the socket for the battery by the passenger door so that you can see it obviously and unplug from the drivers seat.

http://www.twin-turbo.co.uk
http://www.hillclimbandsprint.co.uk/default.asp

A man without a project is like a like a woman without a shopping list.

Remember that the batterys will be year older unles you have bought new ones and they will hold less charge than last year.
I run an alternator on mine and recomend one unles you plan lap records.
Allan
Or until you are close to the lap records

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