Mazda MX-5e Tesla Powered

[robcollingridge]

The Rota Slipstream wheels arrived for our MX-5e today. They weigh just 5.5kg.

[robcollingridge]

normalbloke said:

When are you starting the ‘e’ part?

We have already.

[robcollingridge]

Olibol said:

Very excited by this. I’d hoped to do the same to my MP62 supercharged Eunos, but there was a skill/time/funding gap that I couldn’t overcome, so I swapped it for an electric Mini instead. I’d still love to build/commission an SDU powered NA one day though, and thrilled that you’re doing the leg work!

A concern that I have always had about conversions, particularly soft tops, is that once you remove the engine noise you can hear every creak, clunk and rattle. All that power and torque will exacerbate the flex and groaning too. Have you got any plans for stiffening things up? I found a decent half cage and some bracing was quite effective, but I wonder if you might regret getting rid of all the sound deadening. Or you could just turn up the stereo

We have actually removed most of the sound deadening from the interior because the car is going to be so much quieter as an EV. Most of the dynamic testing we are doing now (and why we MOT'd the car to road test it before converting it) is looking at this stuff. We have completely replaced the braking system and fitted new coil overs to reduce the noise. We are doing a complete suspension refurb when removing the sub-frames and these will be shot blasted and powder coated. All of the bushes are being replaced and if you look at my progress blog (just been told off for posting a link to it ), you will see we have fitted new poly bushes to the ARB components.

We have also stripped the doors and electric windows, which have been rebuilt with new cables, precisely to remove rattles. It's a commmon issue on the MX-5. We also have new door to window seals once the car has beeen resprayed. I'm currently fitting Delrin door bushes to ensure the doors close and are held more firmly.

My road testing so far shows the car is remarkably quiet for a 1992 soft top. The auto-box and over drive helps with this testing Either way, if we find any noises will investigate and fix them. We have also fitted a very nice stereo system with a 10" Apple CarPlat screen, sub-woofer, etc. So we can make the noises go away

Rob

[robcollingridge]

We are also stripping components like the heater matrix to help reduce the noise. After 20+ years, the foam on the flaps has crumbled to dust. This is a project in it's own right. You can read more details in the projects section on our OSSEV website. This is the level of restoration that most people never bother with on old cars but, as we are fitting a 500V PTC heater inside it, it made a lot of sense to do it all in one go.

Even things like the wiring loom will eventually be replaced.

[robcollingridge]

To answer the EV conversion question, these are our goals for July:

1. Refit the MX-5e fan unit. - DONE
2. Refit the heater matrix with a PTC heater. - IN PROGRESS
3. Ethan to complete his EV conversion course with Fellten. - The online bit is complete. He has two days in Bristol this month.
4. Buy and fit the iBooster to enable electrical assistance for the brakes. - I'm on it now
5. Depower the steering rack and modify the rack to reduce the internal resistance. - TO DO
6. Buy the new wheels and tyres. - DONE
7. Fit a CAN Bus compatible Tyre Pressure Monitoring System (TPMS) to the wheels and fit the tyres. - Just looking at options now
8. Buy a Telsa SDU and start the required modifications. - I'm on it now.

[robcollingridge]

Craikeybaby said:

Your project website seems to be down, or at least what I think is your project website, before the links were removed...

It is working. Google OSSEV.

[robcollingridge]

Olibol said:

You obviously know your MX5s, but having done most of what you describe to mine it was still pretty noisy. I dread to think what weight I added back with dynomat.

Do you envisage having to do a lot of fabricating to get the SDU to fit where the diff is/was? I’d always hoped there was a bolt in solution that didn’t require any cutting.

We have done a complete refurb and rebuild on my son's 1990 Eunos Roadster in the past, so we know the MX-5 NA very well. He has his own web site too.

We are going to have to cut into the rear sub-frame slightly and remotely mount the inverter from the SDU on top of the motor unit. We have a guy in the project FB group that has modelled this all on a CAD system. I don't weld but I know plenty of very good welders and fabricators that can help us with this part.

We also have a spare pair of sub-frames and suspension arms to work with. We bought a second set to get shot-blasted and powder coated, to go on my son's 1990 Eunos.

The group modelling has also shown that we can fit a fast CCS charging port within the existing petrol cap too but, we are still deciding if we need this on our test MX-5e.

There are loads of options for the batteries in terms of weight distribution and we have quite a few CAD models for this too.

[robcollingridge]

shalmaneser said:

I think you're missing the point of a readers car thread

The idea is you post stuff here not just push traffic to your blog.

Just repost it, it's not hard.

And that's fine with me as this thread is about the MX-5e but people ask questions about the wider OSSEV project which is developing a new open-source Sports EV. I'm not going to post that all here when it is easier to link to the website, where it is all described in detail. The MX-5e is just a test platform for a bigger project, where we can test out components and the concept.

It's not my blog. That's another website entirely which I won't link here

[robcollingridge]

We have bought a 2nd gen Tesla iBooster to provide electrical brake assistance (replaces the brake vacuum servo) and to enable programmable regenerative braking. This will be fitted this month.



We have finished completely stripping the MX-5 heater matrix. The foam on the internal flaps had crumbled to dust. Each flap has been cleaned, painted and fitted with new foam, to ensure the flaps seal properly and to also make the whole thing quieter over bumps. It was like having a drum kit under the dash before! We can now fit a high-voltage PTC heater in place of the old heat exchanger, to provide hot air into the cabin if required.

[robcollingridge]

The Tesla iBooster arrived. We can now swap the braking system to 12V power instead of ICE power and the plan is to have programmable regenerative braking based on driver mode, etc.

[robcollingridge]

Whilst on holiday this last week, I've been sorting out bits for the upgraded lighting. We are going for a 'stealth' look on the MX-5e given that the car is black, using dark tinted lighting where it is safe to do so. All of it is being upgraded to LED and made brighter, to make the car more visible in the shadows and at night. The 'marker lights' (reflectors) are being converted to extra indicators and the side lights to bright DRLs.



The MX-5e lighting upgrades are described in detail as a project on the OSSEV website.

[robcollingridge]

We are trying to do the basic restoration first and then the conversion and upgrades in parallel, to speed the process up as much as possible. The OSSEV project is over 100 people now, collaborating and helping so we are not doing this alone. There are some very experienced people onboard and some that have done conversions like this already.

The whole MX-5e project is progress limited by me and my son finding time to do the actual work on the project. Right now, I have a terminally ill father that requires a lot of my time, so it's not progressing as quickly as we had hoped but, I'm trying to keep the project moving forward as best I can. My son is on an EV conversion course with Fellten next week.

Our target was always to get the MX-5e up and running as an EV in 2023 and this is still the plan.

Rob

[robcollingridge]

My son completed his EV conversion course at Fellten this week, with two days in Bristol

[robcollingridge]

Progress has been slow this month. My Dad has been ill, following a heart attack and stroke, so I had to be there for him. He died last week.

Things should move forward a bit quicker next month. We have now bought the motor and inverter for the MX-5e.

[robcollingridge]

Fitted the new Rota 15" x 7" alloys with Yokohama AD08RS tyres. The ride, handling and grip levels are now right where we want them to be

[robcollingridge]

Ordered the electric motor for the MX-5e and the Thunderstruck VCU. We have gone for Nissan Leaf power, to avoid making structural changes to the rear sub-frame. This is less power than the Tesla unit but, still plenty for a car like this and it makes our life a lot simpler. We have also ordered the Thunderstruck VCU, so we can get the motor running on a bench quite quickly and test a lot of stuff out before it is fitted in the car.

The motor installation is described in a lot of detail as a project on the OSSEV website.

Fitted the front lip spoiler from Bofi Racing today too.



This car is growing on me already despite the lack of speed from the 1.6 petrol engine and the slow autobox currently fitted. When driving some of my local favourite B-roads it is proving to be a lot of fun already. The driver involvement is good, the feel through the steering wheel very good. With the new wheels and tyres fitted, the grip levels are really highn and the new braking system inspires a lot of confidence. I'm really looking forward to a bit more pace and an instant throttle response

It's never going to be as raw as my 450kg Fisher Fury R1 BEC but, this is meant to be a car that the whole family can enjoy. My wife would never even sit in the Fury R1 as a passenger

[robcollingridge]

Flying Phil said:

Hi Rob
With the Leaf motor having less power than a Tesla unit, will you go for a longer range or use fewer batteries and reduce the mass slightly? I think the power loss will not matter to most users most of the time, as I'm sure the leaf motor will give better performance than the existing 1.8 ic engine(?).
PS you will need to change the thread title though....

The plan is to still fit around 30kWh of batteries. Power will be lower at around 165bhp but we will still have lots of torque.

Can the thread title be changed by me?

Rob

[robcollingridge]

The Nissan Leaf motor arrived today

We are aiming for less than 1000kg for the final weight.

[robcollingridge]

Stripped it down to just the motor and inverter. We are using a Thunderstruck VCU to control and interface this and will be doing some testing in the next few weeks.

[robcollingridge]

Enjoying driving the MX-5e and testing stuff whilst we do the research and ordering of parts. Fairly soon, she goes up on ramps and the engine/gearbox come out.