Lotus Elan Central

Just starting with the concept and will add details later. End game is for the car to be more reliable than a modern vehicle on the electrical side, run 200bhp which can be de-tuned easily to 100bhp.

I am going to build out the rear wiring and the lights using MaxxECU PDMs, but the final engine and work will be done by an ECU/Engine builder who I know well in Grove. Apart from some tails no original wiring will be used, not a single fuse or relay is needed.

Dynamically car will be standard apart from GAZ Shocks, probably need softer springs knowing them but we shall see. PNM to supply front calipers and disks, also getting a 2.25 exhaust and the cat eliminator unit from the turbo. Turbo likely to be refurbished by Owen Developments as they did the Lancia ones pretty well.

Engine will be a bit more interesting, electronic throttle (Bosch) makes everything so much simpler. Probably keep the secondary throttle but it looks like a simple On/Off flap. Only the dyno can tell how useful it is. So no idle control valves and all that stuff, same with boost control none of that will be needed as it will be done electronically. None of this is set in stone as I need to sit down with the engine fellow, all the manuals and just see how much we can remove.

More to follow....

Cheers.

Once you start delving into the wiring and how the switchgear actually works you really feel for the pre-digital era designers. There are so many little tricks needed to make things work with each other, it's a much more complicated affair than I imagined. Chapeau really. You can see now how Tesla can keep prices so low by just giving you a tablet.

The limit factor with the MaxECU PDMs is the Inputs and knowing that one needs to leave the ECU inputs for the engine I've had to use a few tricks as well. Instead of using a bunch of simple digital signals I have had to use analogue voltage ladders to get multiple signals into the PDM using a single wire. Basically, instead of On/Off I get say 5v, 3v, 2v, 1v, 0v. On the flipside the PDM output a known and stable 5v with internal Ground, so no need to build voltage table to compensate for common ground or alternator speeds.



Above are the window switches and stalk commands, the black wired are AIN (Analogue IN), pink are Sensor 5v and rest is usual.



I used the original voltage controller to rewire the rheostat. It will be driving LEDs in the dash. However, the switches will not be dimmable, there is a mix of common grounds with signal lines which means that Hazard, Fog, Window switches backlights are likely to be simple On/Off.

Otherwise, the chassis is almost done and epoxy primed. Next week I should have all the parts to start rebuilding the rear end at least and hopefully get the car rolling and ready to have the engine looked at by the end of the summer.

Just fit one of Ron's chips and you have 200hp.

Simon_P wrote:Just fit one of Ron's chips and you have 200hp.

True, but not 100 when my daughter drives it to school!

I do have the code for a "No-Boost" version which opens the waste gate as soon as the turbo starts to spool - so probably around the same as the NA's 120 BHP......
Add a key switch and - Voila!

RonR wrote:I do have the code for a "No-Boost" version which opens the waste gate as soon as the turbo starts to spool - so probably around the same as the NA's 120 BHP......
Add a key switch and - Voila!

Very swish indeed.

RonR wrote:I do have the code for a "No-Boost" version which opens the waste gate as soon as the turbo starts to spool - so probably around the same as the NA's 120 BHP......
Add a key switch and - Voila!

i believe it should be in theory a little lower in fact.

the NA engine has slightly more compression. it would be an interesting test for myself to compare. because i suspect my NA is under the 120 thats supposed to have .

Most of the electronics are now done from the inputs side. Lost the battle with the Hazard switch and its simply too difficult to get reliable. I have opted for Blink Marine canbus switches for Fog, Hazarad, and a new "daughter configurable" switch which will probably involve some blinking and quick toot of the horn. Photos later on.

In the meantime, I have found a way to get decent light for the instruments, Problem is that LEDs are very directional so I tried all sorts of solutions, from frosting to a reflective cap. In the end found some with good number of small side SMDs and had to Araldite brass fittings to be able to use the rubber holder. Have some new LEDs coming with three times the amount of side SMDs and each one is much smaller.





Otherwise the T.47 units from ClassicLEDs went straight in, I am not using the original circuits so had to solder tails. Eventually they will go into a Deutsch connector and back to the PDM.

i can see those cilinder sticking out.

i dont think you will have problems, but keep in mind the clearance and particularly the fact you need more clearance to install it than it needs when its seated.

Tuga2112 wrote:i can see those cilinder sticking out. i dont think you will have problems, but keep in mind the clearance and particularly the fact you need more clearance to install it than it needs when its seated.

True, but it should be ok if you consider there is a lot less wiring in the car, no relays, no fuses. Just wire from switch to box and out to whatever needs controlling.

Cheers.

im thinking specifically of a metal tube that runs along that area. i suspect it to be part of the crash structure. my recollection is that it looks pretty beefy material

Tuga2112 wrote:im thinking specifically of a metal tube that runs along that area. i suspect it to be part of the crash structure. my recollection is that it looks pretty beefy material

The tube where the relays are fixed onto? I think that is much higher up but will check when back.

Currently trying to figure out how I can get the whole dash to light up red when hitting the red line (or any specific RPM). Got some LEDs internally but it's just not strong enough for daylight. My daughter wants one of these on the dash:

https://carmoody.com/products/turbo-boo ... pDFv_OTouu

they look like a lot of fun. and probably 1/10 of the price in aliexpress

as far as making it light up red in the dash, i know how i would do it. if someone was payuing me enough for the time it would take.

i would put something sensing the voltage of the rev limiter. and that unit would control the LEDs with mosfets.
if voltage below x power up the white LED bank, if above the threshold power up the red bank.
id make the threshold be contorller by a potentiometer.

but then again... the principles of the electronics are simple. the decision on "what IC" or "how" to do it without a IC (to prevent draining the battery) how to make space for the LEDs and extra wires etc is where the real dificulty stands.

Tuga2112 wrote:if voltage below x power up the white LED bank, if above the threshold power up the red bank.
id make the threshold be contorller by a potentiometer.

What I found is that it's not bright enough in the daytime to be visible in your peripheral. The clocks are backlit so the only way to do this ultimately is to (I think) add a series of LEDs into the rev counter itself, so that they come out of the plastic background plate.

i did say making space for the LEDs and extra wires inside is the actual dificulty

if i had the patience the option of modelling my own dashboard and 3d print it would be an option... theres lots of ideas in my head waiting for that first day of retirement

I have pretty much completed the full bench build, few bits left but no real mysteries. I also trained a GPT with all the Lotus manuals and wiring diagrams as well as the MaxECU full manual.

I now have time to start again from zero and have a proper clean software installation, also from a hardware side I just found these MEC18 modules which for a few 100 quid give me a fully functional extra 9 digital and 9 analogue inputs. This means I can throw away all my voltage ramps and have much more precise inputs and never have to worry about voltage issues. Also means keeping the 5v rail with its own ground purely for engine sensors and nothing else.

https://www.canchecked.de/mce18-can-bus-extension/

It's says it also works with Motec, which means I might end up doing the road Lancia as well. It is on Motec for the engine side, but original for the body.