the butterfly effect

[jesfirth]

I was having a lovely day at gurston hill climb with my griff. I did a personal best in practice to take the lead in the event. BUT as I got on the final straight my battery warning light came on because the alternator had failed - ok no worries I thought - just keep my foot hard down. This is where the butterfly effect comes in - the alternator drives the electric power steering pump so when I got to the last slight kink and over the finish I tried to turn and the steering didn't react quickly enough so off into the field. I only just managed to keep it out of the wall. So now I need a new alternator, 2 new front tyres to replace the now flat spotted ones and refit the exhaust which was knocked about - oh and some new underpants. who says motorsport isn't fun.

https://youtu.be/rE11rQtIn20

[jesfirth]

phazed said:

Are you sure it wasn't your 100 amp fuse?

I took a dedicated feed from the battery through another fuse link to my PS pump.

that was suggested on the day. but I don't think my car has one. we jacked it up and had a good look form beneath and there are no cables etc on the chassis only feeds to the starter the usual earths and small wires to the oil sender plus wires ofr the fans, lights etc at the front.. where is it normally located?

The AA chap who recovered me tested the alternator and said it was not putting out any current.

I think I will do the same as you - I assume that you have the switch box so the pump only runs on demand?

[jesfirth]

phazed said:

Just in front of starter.

just had a really good luck under the car and no 100 amp fuse. so ordering an alternator now. any views on capacity. mine was the 65 amp original. various TVR specialists seem to sell 100 amp alternatives. why?

[jesfirth]

phazed said:

Our cars are over alternatored. You will get away with a lower output.

thanks much appreciated -ordering a 70amp one...

[jesfirth]

thanks - that has really helped my numpty level electrical understanding massively.

the key on the electric PS pump is to have them wired with a switch thingy (not sure what it is called) so it only runs on demand. that's what mine does and, I think, all the T cars have it as well. That reduces the amp load considerably.

[jesfirth]

thanks will try that.

[jesfirth]

Firstly thanks for the help and advice. New alternator fitted and everything working as it should. Went for a lovely drive to "test" it and the rear view mirror fell off the windscreen under hard acceleration. LOL.