5v source for TPS?

Lotus-e-Clan · Post by **Lotus-e-Clan** » Wed May 07, 2008 19:11

OK

Without thinking it through I've bought a Weber Alpha TPS for my Wideband Commander Air/Fuel ratio datalogger.

The TPS needs a 5v reference source which is normally provided by an ECU except of course I'm not running mapped ignition or EFI.

So I'm wondering if I could use a 5v car adapter normally meant for in car digital camera charging. Would it be stable enough for a 5v reference.

I haven't got one to test so does anyone know if this would be stable enough...or any other ideas?

Steve C · Post by **Steve C** » Wed May 07, 2008 22:07

You may find that the 5v chargers run somewhat higher, probably depends on each particular charger ..

You could just use a 7805 5v regulator from maplin, part number CH35Q .. stick a 10uf capacitor across the output, maplin part VH22Y will do ... parts total about a quid plus a small piece of stripboard and some wire!

That should give you a nice solid +5v ...

If you're stuck I can build one for you ..

Lotus-e-Clan · Post by **Lotus-e-Clan** » Thu May 08, 2008 08:22

Thanks Steve that's the sort of thing I'm looking for! I'd prefer to do something like that.... ie built from scratch.

Need to find a Maplins near me ..or I could order online.

Steve C · Post by **Steve C** » Thu May 08, 2008 10:07

I already have the bits to build one if you want? .. you'll just need a little box to put it in!

Lotus-e-Clan · Post by **Lotus-e-Clan** » Thu May 08, 2008 10:30

Ordered parts from maplins (plus a new 12v soldering iron for working at the car)

will let you know if it works!

Thanks!

Lotus-e-Clan · Post by **Lotus-e-Clan** » Thu May 08, 2008 10:34

Little box with order...

How would you heat sink the regulator (if necessary)? small bolt and washers or what?

Steve C · Post by **Steve C** » Thu May 08, 2008 10:46

The voltage drop and current draw are so low that a heatsink won't be needed. I'd be surprised if more than 1ma is drawn through the pot ... which means the regulator is dissipating around 1/100th of a watt. Way under the heatsink required line n the tech specs!

We could probably have used a smaller regulator too but you now have a nice 5v source with 999ma spare capacity and it's only 13p dearer than a 0.1 amp regulator!

Lotus-e-Clan · Post by **Lotus-e-Clan** » Thu May 08, 2008 10:55

Thanks again steve!

When up and running, the TPS info will help make more sense of the data from air fuel ratio v rpm on road testing.

Steve C · Post by **Steve C** » Thu May 08, 2008 11:20

I've got the Innovate LM-1 wideband controller and LMA-3 aux-in box and was planning the same thing, to feed in the TPS into the aux box (or LM-1) so that it will log TPS v RPM v Air Fuel to help map tuning! The LMA-3 will also log lateral and fore/aft G force too so I could probably calculate all the 20mph acceleration bands in all the gears too ...

So many plans .. I just need to get on with it, the weather is better so it's time to tinker!

Pete Boole · Post by **Pete Boole** » Thu May 08, 2008 18:24

Hi guys

How many wideband controllers did you look at before buying yours?
I'm going to need one in the not too distant future to tune my V8. What made you choose the ones you bought?

Pete

Lotus-e-Clan · Post by **Lotus-e-Clan** » Thu May 08, 2008 19:03

I nearly bought the one that steves got but the permanent in-car 52 mm AF ratio guage swayed me toward the Wideband Commander, it's really handy. However the G force bits aren't available with the Wideband Commander so steves got a valuable tuning aid there.

The other downside is that I've got the WBC permanently installed in my Clan so I haven't used it with the Excel as yet!!

Also I got it cheap on ebay second hand....Â£120 virtually unused with a new weld-on manifold boss.

The WBC has a programable output to control relays (like water injection or other devices) although I haven't dreamt up a need for that yet.

Pete Boole · Post by **Pete Boole** » Sun May 11, 2008 20:14

Thanks Peter

I've got no experience using 'modern' tuning equipment yet. I'l be using EFILive to modify the PCM, but it's going to be a steep learning curve

.
All this while sorting the brakes, suspension.....!

Pete

p.s. I used to live on Bargate in Richmond!

Lotus-e-Clan · Post by **Lotus-e-Clan** » Mon May 12, 2008 08:08

Pete Boole wrote: p.s. I used to live on Bargate in Richmond!

Cobbles! (it hasn'tchanged) Nice location but nowhere to fettle a Lotus...what with the gradient and cobbles ...and not many houses with garages down there!

A/F ratios are very useful but I still reach for the coloutune plugs to see whats really going on in each cylinder.

Lotus-e-Clan · Post by **Lotus-e-Clan** » Mon May 12, 2008 08:13

Steve

5v regulator /10uf capacitor works a treat...all nicely fitted into a small abs box with three wires emerging... Gnd, 12v input and a 5v reference output.

Ordered bits from Maplins at lunchtime on the net and they delivered next morning....box up and running by the afternoon.

Thanks