alternators on race cars

[dtype38]

Originally Posted by racing59

I've got one of the little Edge Performance alternators on my Chevy engine. It's three wire, battery, ignition, and light, but nowhere on the box, or on the paperwork that comes with it, or even on the suppliers website, does it tell me which pin in the connector does what. The output is a 6mm stud, that's simple. The other two are spade connectors, one is perpendicular to the other, for use with a bespoke connector shell.

Even without the ign/lights wiring attached, yes, it charges at 3000 plus.

Must get it sorted properly. Anyone got one, and have the terminal connections?

Rob.

Yes I've got the same one. The two small connectors make a "T" shape. The upright of the T is the ignition warning light connection. The top bar of the T is a +12V reference connection and should be connected to the supply for the ignition coil. I just use two small spade connectors on both. With the latter connected it should charge at any speed

[Dauntless]

Originally Posted by Denis Bassom

Thanks for that Dauntless, it's nice to see one of my pet theories actually proved 'scientifically'!

My pleasure, Denis!

And bear in mind that those were the results for a carburetted engine. Add EFI and/or data acquisition, not to mention lights, and the slope just gets steeper.

When I was hired this year by Ishikawa Racing their car had a total loss system...along with EFI and a thorough-going DA system. During our first test days the driver sometimes radioed in that the power seemed down near the end of the 30-minute session, so I suggested we install an alternator to assure full spark and injection strength. But when the team owner spoke with his engine builder he was told that the car didn't need an alternator, and that a good, fully charged battery should last an entire race.

To resolve the issue I suggested we see how long the battery would run just his (electric) fuel pump. It died after 45 minutes...perhaps adequate for a 30-minute club race, but not enough for a 50-minute Champcar Toyota-Atlantic race. In the end we changed engine builders, both to gain an alternator and to run the same engine as the front running Atlantic teams.

Regards,

[greenamex2]

Yep, got them all and may have another fuel pump soon!

[graham bahr]

just when you thought this thread had died.....

my alternators going in the BIN! along with the Varley!

its failed twice this year and almost caused 2 DNF's!

chucking the alternator away, will save a fair chunk of wieght which will mean i can move my rad backwards and fit my new much bigger heavier intercooler without upsetting the weight distribution, in fact by the time i've put a nice big battery in the boot i will of improved the weight distribution.

[greenamex2]

We have had instances where alternator failure has drained the battery. And small Varley red tops do drain very easily.

So far the Brise alternator and Red top 40 have done us proud.

I just couldn't bring myself to fit a battery big (read heavy) enough to cope with a days practice and racing on a car with a constant 25 amp draw even it isn't raining! I also couldn't cope with replacing it every few months because batteries are allergic to being discharged/recharged (especially Red tops).

Still I can see the appeal of improving the weight distribution, especially as my rear axle weighs as much as the rear half of my car without rear axle or driver. Oh for a de-dion axle.

[Dauntless]

Sorry to hear that you've had two alternator failures this year, Graham. But since properly installed alternators routinely last several years in racing conditions, I would suspect misalignment or over-revving, and find and fix the problem, rather than simply tossing the system in the dust bin.

Before installing an alternator, I went through 2-3 Redtops a season at ~$200US apiece. Since installing the alternator and switching to a $35 motorcycle/ATV battery I've never had a problem. I do toss the battery at the end of each season, but have never had one go bad.

We all "pays our money and takes our choise"...good luck!

[dtype38]

I run my Jag on a little 30Amp Edge alternator and a little Varley Red Top 15. Been good as gold for three seasons now :-)

[greenamex2]

Your jag engine must be easier to start than my little 1.6. I was getting through 2 red top 20's a year before going for a 40!

[dtype38]

The Red Top 15 has more starting amps than a 20, but less reserve... they're wired up differently inside according to Varley. I also use a Cambridge geared starter which makes a massive difference to getting the engine to turn over :-)

[graham bahr]

Originally Posted by Dauntless

Sorry to hear that you've had two alternator failures this year, Graham. But since properly installed alternators routinely last several years in racing conditions, I would suspect misalignment or over-revving, and find and fix the problem, rather than simply tossing the system in the dust bin.

We all "pays our money and takes our choise"...good luck!

its been falling to bits in an electrical sense, probably something to do with it being a lucas unit! i am well aware of over reving issues but not in this case, being a turbo lump my engine peaks at 6,000rpm and its on std factory alternator gearing so revs arn't an issue, neither is missalignment. it could be its objecting to the std rubber bushes with deform with revs time etc and causing missalignment therefore throwing belts being replaced with something stiffer.

i have no issues with the varley its been great as long as it gets charged, but if i need to run a big battery incase of alternator failure i might as well leave the alternator off in the first place and have the other benifits

[Dauntless]

Oh, it's a Lucas...why didn't you say so?!

Sorry mate...get a nipon denzo or other 'proper' alternator and see your problems go away.

j/k...I wish I had the magic answer for you, but the confession that you have a Lucas was just too good to pass up (see threads on old Brit cars...). Please read my earlier comments about losing power without an alternator. That was on a carb'd engine. Add a turbo and injection and the challenge just gets worse.

Cheers!