Jump to content
Sign in to follow this  
RealWorld

Race car electrics

Recommended Posts

Read the regs as to what you can do ie front lights etc are they required in a road based car class? Then rip all the wiring out and start from scratch with aircraft grade if you want to be mega light. There is no point having loads of extra stuff on the dash, rpm gauge, temp and oil would do me with warning for oil pressure and charge (maybe) and a ign on/off and a starter button. Wipers? heated screen/blower? Fuse and relay everything as it should have been. Make sure your starter wire is rated to take the current required to start the car, Simon Benoy is probably still running round with my doubled-up jump leads from Oulton last year when his cable melted.

Share this post


Link to post
Share on other sites

Thanks for all the input. The rewire is well under way, incorporating many of the ideas above.

I'll post pics when there's more to see, but so far so good.

 

Just a couple of quickies - I'm sorting wire grades for different circuits (I have 12 independently fused). Opinions on average current at 12v for the following please:

 

- Pacet fan

- Fuel pump (red top)

- Water pump

 

Thanks!

 

Share this post


Link to post
Share on other sites

Can't you just measure them with a meter, most digital ones go upto 10A.

That may not be enough for the pacet or the waterpump however.

Thing to do then is find a long piece of electrical wire, measure the resistance.

Then place the wire with the now known resistance inline with the device you want to test and measure the voltage loss along the wire.

Suppose the wire is 0.1 Ohm and you measure a voltage of 1.5V then the amps the device is drawing is:

R=V/I => I=V/R = 1.5/0.1 = 15A

 

Cheers,

 

Frederick

Share this post


Link to post
Share on other sites

Impressive grasp of electrics, Frederick!

No, really, I struggle.

 

I've got a "clamp meter" (see: http://www.digital-meters.com/products/AC%7B47%7DDC-Voltage-&-Current-Clamp-Meter-%252d-Tecpel-DCM%252d033.html)

The orange loop opens to let you place the wire inside, and then closes to read the current, without any connection!

I understand at a v.basic level how this could work with an AC current, but is works with DC too!

Connect your item with cheapo wire, measure the current, then fit wire that suits.

 

Simples!

John

Share this post


Link to post
Share on other sites

That would work even better of course, but I doubt Richard has one of those.

I agree they are very handy, and er... don't know how the DC version works either.

 

Frederick

Share this post


Link to post
Share on other sites

When measuring the fan will draw much more amps on startup, so you may have to go one step up on the fuse.

 

Also are you going for blade or cartride fuses, most likely blade I think.

 

Keep in mind they rated differently than the old glass fuses;

Blade rating is for continuous use, cartridge is blow rated.

So a 15 amp blade fuse will not blow at 15amps whereas a 15 amp glass fuse will.

 

Cheers,

 

Frederick

Share this post


Link to post
Share on other sites

John wrote

but is works with DC too!
Frederick wrote
and er... don't know how the DC version works either.
Guys, low cost ones only measure AC. Slightly less low cost ones do DC as well. Works with a Hall Effect Sensor. Although the magnetic field is steady state, the electrons in the Hall sensor are moving across the field, causing them (the electrons) to move to one side of the sensor element, creating a voltage across the sides of the element. CPC (no interest) don't seem to have any in their "bargain corner" at the moment, but this is the sort of thing. Very handy piece of kit for doing a current audit in your car :¬)

 

Richard

Share this post


Link to post
Share on other sites

Thanks for explaining Richard.  :)

Never would have guessed they work with a simple hall sensor. :B

Share this post


Link to post
Share on other sites

Thanks chaps.

 

You're right, I don't have a clamp Ammetre, but do have a diploma in electronics (from some time ago!) so am quite agile around electrics - I was just looking for a shortcut in planning wire capacities. But, as is often the case, in the absence of proper documentation running each pump/fan up from a battery through the multimetre was the best/fastest/most accurate solution.

 

Water pump - 4.5 Amps

Facet red top fuel pump - 1.5 Amps

Pacet fan - 15Amps

 

My ultra light 0.5mm squared wire is rated at 11.5, so I'll allow accordingly.

 

Cheers

Share this post


Link to post
Share on other sites

Here's me, a guy who needs to look twice to put the battery in the right way around, giving advioce to someone with a diploma in electonics!

I'm schtum in future.

 

John

Share this post


Link to post
Share on other sites

You can run basically everything bar the headlights and alternator charge wire off the smallest thinwall available.

 

Vehiclewiringproducts.co.uk or .com or .eu or something.

 

I mean there is really nothing running a load.

 

If you want to be safe run the 2nd to thinnest for the wiper motor if you have one... + the EWP.

 

What else is there, taking any real load, nothing.

 

That thinwall low amp stiff is like almost as thin as a human hair.

Share this post


Link to post
Share on other sites

Can, my old kenlowe did, must have been 20amps!

 

My new Pacet uses 8amps! Running it on micro thin wall :)

 

Actually it's not connected atm as the sensor has gone bad, oddly it's not needed...I can idle in traffic for 10mins before it hits 100C...Best remember to fix it before any city runs? :)

 

 

Share this post


Link to post
Share on other sites

Mmmm - it's odd IMHO how over spec'd traditional Triumph car wiring is. I only used thicker wire than microwall for the fan (pulling approx 11amps), main lighting feed and alternator to battery charge circuit. EVERYTHING else runs on the smallest microwall - rated at 11amps.

 

Seems good so far - guess the proof will be on the track though ;)

Share this post


Link to post
Share on other sites

But ya can really use one when that Loong grid comes up.  At least in our part of the world.  Still likely to overheat on a long grid even in your climate I'll wager... ;)

Share this post


Link to post
Share on other sites
On track, you won't need a fan at all.

JOhn

 

Not when in clean air but when running 1/2" behind the rear bumper of the car in front one can be pretty useful.

 

Also as Steve says I always run mine when waiting on grid, in pit lane, cooling down after a race etc etc.

 

I used to run without one but its really not worth the stess of sitting on a grid and watching the needle rise as you pray for the lights to go green/out.

Share this post


Link to post
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now
Sign in to follow this  

×
×
  • Create New...