alternators on race cars

[greenamex2]

Starting a light weight single seater with a mildly tuned engine must be a heck of lot easier than starting a tuned to oblivion 840Kg saloon car, particularly if you have to bump it!

[maddogf3]

Originally Posted by Denis Bassom

Starting a light weight single seater with a mildly tuned engine must be a heck of lot easier than starting a tuned to oblivion 840Kg saloon car, particularly if you have to bump it!

we are using hi octane race fuel to stop detonation on our " mildy tuned " single seater . what are you using?

[Al Weyman]

Do as I said and have the best of both worlds, keep an occassional eye on the volts guage and flick on the alternator if it starts to get marginal or you are in a position in the race that 4 or 5 bhp would not make any difference either way. Hey if you wanted to get a bit tedhy why not wire in a switch on the throttle pedal that only kicks in the alternator when you floor it, that way as soon as you get off the gas it starts charging.

[graham bahr]

Originally Posted by Al Weyman

. Hey if you wanted to get a bit tedhy why not wire in a switch on the throttle pedal that only kicks in the alternator when you floor it, that way as soon as you get off the gas it starts charging.

good idea but probably the wrong way round

surely you want to cut the alternator when you floor it and get full throttle power plus the extra 5bhp at the same time, afterall even on a race car you not at full throttle all the time

[Al Weyman]

Sorry I confused that a bit what you say is exactly what I meant, when I said kicks in I meant the relay to turn off the field coil as I also said when you lift of the gas it starts charging.

[graham bahr]

we all make mistakes said the darlek climbing the dustbin.......

[Richy_Rich]

Originally Posted by Al Weyman

Do as I said and have the best of both worlds, keep an occassional eye on the volts guage and flick on the alternator if it starts to get marginal or you are in a position in the race that 4 or 5 bhp would not make any difference either way. Hey if you wanted to get a bit tedhy why not wire in a switch on the throttle pedal that only kicks in the alternator when you floor it, that way as soon as you get off the gas it starts charging.

Which... Is what the original post was about, I think. A device that did exactly that

[greenamex2]

Spooky!!!!

[Al Weyman]

Well in that case we have come full circle.

[Kev_205]

do we start again?

[graham bahr]

something i've often wondered about is using an electric oil pump, if 5bhp can be saved with a waterpump the surely we can save much more power with an electric oil pump, car manufacturers are now using electric powersteering pumps, and back in the 70's blydstein used to LOWER the oil pressure on some of his race engines to save power by not working the oil pump so hard

[Al Weyman]

I'll pass on that one Graham if you don't mind :-)

[greenamex2]

PACE do electric oil pumps but they are only rated to 50/55psi. I think they are more aimed at transmission cooling than anything else.

Like Al I wouldn't risk it. The consequences of a connector working loose just don't bare thinking about!

[Richy_Rich]

How do dry sump systems work? I always assumed they must have to use electric pumps?

[Kev_205]

nah dry sump pumps still work off the crank using a belt. Well my Pace one does at least

[Al Weyman]

Kev is right also you can have a belt driven remote wet sump setup as well with just a single stage pump. I have twin Jabasco pumps on my Penske IROC that cool oil to the dif and gearbox but these are really for 500mile oval track racing. Hey I have just had a brainwave on my other old Chevy Camaro, when I finally get it back out I am gonna switch off the Air Con and the 8 track, I reckon that must be worth at least another 10 brake :-).

[johnh875]

A bloke out here has a Mustang rally car with air con – working on the logic that since you can’t usefully get 400+bhp to the ground anyway, what does it matter if a couple go missing to drive the air con, and he’d rather not boil when the car is shut up running in dust.

[Al Weyman]

More like about 10 or 15 hp to run Air con on an old yank, did you know there is a device that speeds the engine up on tick over to compensate when the air con is on, mind you on a rally car sounds a good idea over there in the heat.

[dtype38]

When I used to race an XJS there was one bloke who had kept all his aircon system fitted just for the drive to and from the track! We only found out because we knew he was running the same front springs as most of us, but noticed his front ride height was nearly an inch lower

Mind you, it was pretty miserable on a hot day without it, especially if there was a long hold in marshalling or on the grid That's partly why I changed to an open car.... now I just need to invent an engine pto system that will automatically raise an umbrella when it rains

[johnh875]

Al, I don't think he went as far as using the old piston-compressor type, but I didn't literally mean 2 either!

dtype you need a roof like I saw on a Lotus 11/23 in a classic car mag on some VSCC event where you had to also carry a standard suitcase or similar. It was basically a bit of flat metal on 4 legs, not very pretty but would keep the sun off!

[dtype38]

I was thinking of fitting a sheet of aly into the square hole in the top of my roll cage.

[Tim Falce]

Why not wrap some cling film from side to side like all good fork truck drivers do.

[graham bahr]

Originally Posted by falcemob

Why not wrap some cling film from side to side like all good fork truck drivers do.

it might also help catch oil from leaks???

[dtype38]

Originally Posted by graham bahr

it might also help catch oil from leaks???

Only if I drive upside down

[zefarelly]

cling film roof, nice idea, a couple of goldfish and you've got a kind of underseaworld !

back on tpoic . . .sorry! . . .when I was at Brise last week I picked up a very nive new aluminium pulley, twice the size of a standard one so it slows the alternator down, it doesnt need to do a great deal and as the revs rise it stops the diodes frying . . . a lot cheaper than a posh alternator too.