Project V6 Elise

[tut]

I guess i'd need to do an Elise Honda conversion myself to see what it really costs.
Woodsport

Now that would be interesting, but if you were able to do it at considerably less cost, I would rather you did not as it would put too many eRisers on the market.

tut

[campbell]

I don't begrudge the installer the other 5K to cover profit (they have to eat!), recoup R&D time and cover warranty.

I expect their wages to enable them to eat. Profit is a reward for their risk in the business, or to the owners / investors thereof. Although I accept that without making a true profit, there is no point in offering the particular service.

Not sure if labour charges are already absorbed elsewhere in that 5k balance. If not, then it's an inaccurate basis being used for the project costing.

[Woodsport]

Post #1 updated

[mainsy]

Looking very

Really enjoying this thread

[Scotsdave]

What are you going to do about getting the rev counter to work as the pulses are obviously going to be different?

Do you have a circuit that will correct the pulses or are you going to replace the rev counter?

Or do you have a much simpler solution?

Great work BTW this thread is ace.

[pete]

Loving your work.

[Kev]

Great stuff Paul!!

When do you think the big key turning ceremony is going to be? End of the week?

[Woodsport]

What are you going to do about getting the rev counter to work as the pulses are obviously going to be different?

Do you have a circuit that will correct the pulses or are you going to replace the rev counter?

Or do you have a much simpler solution?

Great work BTW this thread is ace.

Well i have only done some moderate research into the wiring stage, and it all looks fairly simple. My understanding is that the Elise dash is simply displaying the number of pulses output by the original K series ECU, which in turn takes its count from the crankshaft pickup sensor. Now the 1mz works exactly the same way, it outputs a tacho signal based on the NE+ and NE- from the sensor.

If the 1mz ECU tacho output makes the dash over read then the easy solution is to keep the K series ECU piggybacked in situ, feed that with NE+ and NE- from the crank sensor and then use its output to drive the dash, this is what we do on the Mk3 Mr2 V6 swaps and the tacho reads 100% correctly.

Either way it's covered, even if we needed to fit a Dakota unit to convert the signal, that would be a worst case scenario. It's very important to us that everything works perfectly as it did with the 4 cylinder engine.

Hi Kev, it depends how this week goes really, i am hoping to be able to start wiring by the end of the week, if that all goes smoothly then it could be fired up on Friday, but i still have a huge amount of work before then.

Thankyou for the support chaps.

[robin]

The feed to the tacho is one pulse per revolution. The tacho expects a 12V square wave signal, although it is limited to 5V in the stack using a zener I suspect, so you should ensure that whatever you feed it is reasonably high impedance (I think the K4 uses a 470 ohm pull-up to +12 to produce the high phase of the signal and a transistor to pull low for the low phase).

The tacho has no idea about the configuration of the engine, etc. So if the Toyota ECU produces a one-pulse-per-rev output with a suitable output impedance then you're home and dry.

If the tacho output is open collector (which it might be) you might need to add an external pull-up to allow it to pull high.

If none of that works then you cannot hook it up to the Toyota engine crank position sensor as this will not have the same tooth pattern as the Rover 36-4 configuration and so the ECU will not sync and won't produce the tacho output at all (or perhaps it will, but it won't be right). Instead you'll need to produce some sort of converter box magic that will take the Toyota ECU output and re-shape it into what the tacho requires.

My money is on it just working, though

If you can, you'll want to leave the Lotus ECU installed as it provides the speedo and coolant gauge outputs. Leave it connected to ignition live, ground, wheel speed sensor and coolant sensor signals then drill your block to insert the original black coolant sensor from the K-series coolant elbow and the relevant few wires in the loom. Drop me a PM if you need some help working out which bits to keep and how to wire them.

Cheers,
Robin

[Woodsport]

Thanks for that Robin, spaghetti is a specialty of mine, i am pretty sure it will work as planned having looked at both systems, i expect the 1mz signal to be correct for the tacho but i do think keeping the K series ECU will also work being driven by the 1mz crank sensor.

We do this mod on the Mk3 MR2 which has a totally different trigger wheel on the 1zz engine compared to the 1mz, but it just works.

As it stands at the moment i don't think i need to keep the Elise ECU at all, speedo and coolant temp all look good to go without it according to my diagrams.

Lots of wiring fun to come though, looking forward to it! Many thanks for your offer of help, if the brown stuff hits the rotating thing i may need some input.

Post #1 updated

[roadboy]

Pretty sure you'll need the Lotus ECU for the Speedo and ECT Paul. Unless the Toyota ECU miraculously outputs the exact same signals as the Lotus ECU. The S2 Stack expects a specific PWM signal. The diagrams don't tell the full story.

The S1 is easy in comparison.

Dan

[Woodsport]

Either way it's no biggy really, same deal as the mk3 mr2, which look a lot more complex than this and wiring really is my forte, I'm not expecting it to cause me a problem.

[roadboy]

Not saying its a big problem. Its really not. Just saying I'd be very surprised if you can get away with not using the Lotus ECU.

Cheers

Dan

[Woodsport]

I really think it's a good possibility i will be able to ditch the Lotus ECU entirely, but like we've both said, no big deal if it needs to stay.

Post #1 updated.

[roadboy]

That FPR is truly awful Paul. Surprised by it considering the effort you put into the aesthetics of this conversion.

Surely one of these would be a better bet?