Mx5 Rocketeer V6 Conversion Project

[Lewis's Friend]

I thought I would post a small update as I haven't for quite a while now. The reason for no update has been that I have done nothing to it! Apart from drive it, but even that has been boring (for the thread at least) as nothing has gone wrong and I haven't driven anywhere very scenic...

However, I took it to work at the start of the week in the mist and fog, and managed to get a semi-interesting picture so thought I'd share it; mainly as an excuse to say all is well with it. So not an interesting update, but a pleasant one at least.

20201110_094026 by Jon Fellows, on Flickr

And again but in B&W, for extra art points!

20201110_094051 by Jon Fellows, on Flickr

[Lewis's Friend]

Escy said:

How are you finding it? Has it lived up to or surpassed your expectations?

Good question...!

I'm very happy with it, which is saying something given that there was a period before the ECU swap that just looking at it depressed me. One of the aspects I'm most pleased with is its driveability. Even stone cold it starts first time and drives well. I have no idea what power figures it's making but it pulls well. It was making a rather poor 230bhp at the flywheel with the old ECU and was fairly hateful to drive too. My bum dyno says it's making a reasonable amount more power now but is also nice to drive - dare I say OEM-like? You can put it in 5th at 20mph and it will pull away smoothly (if not quickly) which isn't necessarily useful but I found impressive!

I've also got over listening for every little sound and feeling every slight vibration as a harbinger of total catastrophic failure. If someone else had done the work I wouldn't have been like that at all, but as it was me a certain paranoia set it at the beginning; but even that has passed.

So in summary, I'm very happy how its turned out. There's still lots more I want to do to the car as funds and time allow, but none of it really engine swap related.

[Lewis's Friend]

Bright Halo said:

Have you noticed any difference in the handling. Any change in terms of under steer or oversteer, roll etc?

No difference as far as I can tell (although I didn't have the car very long before the conversion - I'm not an Mx5 owner of long standing).

There is no weight penalty with the swap, and the suspension pickups on the front subframe are the same as a Mx5 NB I believe so there shouldn't be any difference at all. The biggest positive change for me in terms of handling was moving from 8" to 7" wide wheels, but that has nothing to do with the car or swap and just my poor initial choice of wheels!

Suspension-wise the only aftermarket bit on my car is the coilovers, which I'm keen to change to decent ones as soon as I can justify the cost. Everything else is new OE and I enjoy it. It certainly steers better than my old TVR S3, and the engine is actually more driveable too (which says a lot about the quality of either Rocketeer's tune or TVR's!).

[Lewis's Friend]

PushedDover said:

I hear the 'sensitivities' to the hearing and feeling having built the car LF, do you think the Kit itself and indeed the Rocketeer guys would deliver a solid and doubt-free solution?

In fairness, the my sensitivities have all been for nothing - thus far there have been no issues! For me, I tend to be more critical of my own work. If I just bought the car I's assume all was well. As I made it, I worry until it's has proved there's no need to...

I have dealt with Rocketeer and Basset Down Balancing a fair bit and so far they've been good so I would assume they'd do a good job on the turn-key builds. They certainly looked nice in the workshop! They did the ECU change (and all associated work) on my car, and while it wasn't perfect after I collected it, they took it back and spent a lot of time getting it sorted after that at their own expense. They also were very helpful with me regarding handling and wheels etc, which is of course not a part of the swap - but they bent over backwards to help diagnose the problem with mine (the aforementioned wheel width as it turned out).

[Lewis's Friend]

I've seen two come up for sale so far - one unfinished (I think) and this one. It'll be interesting to see what it fetches.

Personally I wouldn't have wanted to buy a complete one, but I wanted to do the work myself. If that doesn't bother you, then it would be much easier to buy a pre-done one! That said, as with any heavily modified car you'd want your wits about you when buying to make sure it was all done to a standard you were happy with. Not attempting to throw shade on the white one for sale I hasten to add!

[Lewis's Friend]

I remember seeing that car on speedhunters when the article was published, its pretty cool. It definitely doesn't look cheap though!

The Rocketeer conversion does keep the PPF setup. And while a revvy engine is great in terms of the character, I can't deny the extra torque is nice (and not overwhelming).

[Lewis's Friend]

After a bit of a gap, it's time for an update on this. Nothing major has happened really, hence not many updates of late! But over the winter I changed the Emotion Technology (the brand you want on your car of course) coilovers with some MeisterR CRDs. I also took the opportunity to service it - as I say, not very thrilling...!

I don't have any in depth photos of the coilover change, but it is very easy and not really requiring a blow by blow account. So here they are installed at the rear:

20210106_155228 by Jon Fellows, on Flickr

And at the front

20201229_160111 by Jon Fellows, on Flickr

I also put on a set of adjustable drop links to allow the car to be cornerweighted.

20210304_144434 by Jon Fellows, on Flickr

And fitted

20210304_145114 by Jon Fellows, on Flickr

I then re-torqued the suspension bolts as close to normal ride height as I could manage.
20210111_101548 by Jon Fellows, on Flickr

I tried setting the ride height myself on the driveway, but found this was horribly inaccurate. In the end, I took it to Northampton Motorsport for an alignment, ride height setup and cornerweighting. I'm very pleased with how it's driving now,, and was also interested to see how much it weighed.
1041kg with 3/4 tank of fuel is the answer. They also said they were surprised how light it was at the front. Apparently they frequently work on a turbo converted Mx5 which is heavier - so nice to see the claims of no weight penalty for the conversion are true!

After all that, I serviced the car and cleaned and liberally sprayed ACF50 on the coilovers to try and preserve them. As far as servicing the car goes, you'll have to imagine what that looks like! But I also checked the throttle body balance and tweaked that slightly.

20210131_151530 by Jon Fellows, on Flickr

20210131_153953 by Jon Fellows, on Flickr

There, another exciting update complete! I have only driven a little on the new setup and new coilovers, but they feel much more suited to the local roads. They have a good bit more compliance which is very important where I live!

[Lewis's Friend]

Krikkit said:

Fantastic to hear it's proving a good conversation. Compliance is all too often forgotten in aftermarket suspension, often because it's designed around perfectly smooth roads.

I'm very pleased with it happily after all that work!

Still a lot to be done, but not on the conversion. Just getting the rest of the car where I want it. Weirdly it's the boot next as that has been disgusting since I bought the car!

I'm definitely a fan of lower spring rates for the local roads. It means it's more enjoyable more of the time...

[Lewis's Friend]

After some time without an update, I remembered to take a few pictures and highlight what I've been doing lately on the MX5.

The interior on this car is a bit tired, and so (very) slowly I'm trying to do it up a little. This time was the door cards. Mine are knackered, didn't originally come with armrests (which I like - some remove them for extra space), and weirdly have speaker aperture smaller than the speakers so that they set the whole door card vibrating when they play...

20210619_101532 by Jon Fellows, on Flickr

Not beautiful. You can buy ready made new door cards, but none would be right for my speakers. Plus I thought I'd be cheap. With that in mind I bought a large sheet of 2mm plastic and borrowed a jig saw.

20210522_113033 by Jon Fellows, on Flickr

I traced the old door card out as a starting point and started cutting and drilling until I had this:

20210601_120456 by Jon Fellows, on Flickr

A fair amount of fine tuning was required, especially regarding the speaker setup, but eventually I had this:

20210621_172848 by Jon Fellows, on Flickr

Then I needed to cover it and make it look splendid... So I spray glued a layer of 3mm scrim foam over the card, then glued the faux leather quilted material over the top and round all the edges. I'm pleased with the result, and am mainly now hoping it lasts. Time will tell!

So, to the finished result...

20210809_104010 by Jon Fellows, on Flickr

20210809_104035 by Jon Fellows, on Flickr

[Lewis's Friend]

unlikelymechanic said:

Your car is looking awesome- I like the wheels and interior mods

How have you been getting on with the car since your update in April? Has the MBE been reliable?

I am in the same predicament that you were in - I am struggling to get anywhere with the ME ecu - I did the firmware update hoping for great things and it has just made it worse - rich running etc. It has always had a hot starting issue even after ME tuned it after the initial build. My car is currently an expensive garage ornament gathering dust as home diy and family life have taken priority. Before my wife starts piling boxes on top of it I have decided to bite the bullet and have booked it in with BD to have the MBE and throttle body upgrade so I can hopefully use it as a reliable weekend toy which was my intention when I first built it.

Thanks very much - apologies for not replying sooner; I didn't see your post.

So far the MBE has been great - a total transformation. The only issue so far is that after getting stuck in nose-to-tail traffic for 45mins due to an accident and road closure, it lost the ability to idle! I think this is due to under-bonnet temps getting so high (the outside temp was about 28degC with loads of direct sunlight) the map hasn't been written to cope with such a high inlet air temp. That aside, it's been good.

Basset Down are currently working with MBE on a fix as while this issue has only effected me once, it could be more of an issue in hotter climates.

Sorry to hear of your troubles. I was in a similar position and not enjoying the car at all. All I will say at this stage is that I am vastly happier now nothing made by ME is on my car.

[Lewis's Friend]

Thanks for the kind comments - the last thing I need to do on the door cards (apart from make the driver's side) is to remake the tweeter surrounds.

I originally made them from MDF as a proof-of-concept bodge and they've been like it ever since. They're OK, but are starting to crack. My aim is to draw them up in CAD and have them 3D printed. The only hurdle is that I haven't used CAD for years, so will have to find a free bit of software and get used to it all over again!

[Lewis's Friend]

Thanks for all the software suggestions.

I fear that it may be a little complex to draw up (for a man of my limited skills anyway!). The basic shape should be nice and simple, but the face that bolts up to the door card will need to match the contours of the card. I've not thought how to do that yet, so some tutorials will be a must!

[Lewis's Friend]

After a fairly lengthy break, I have just finished another job so thought I would update the thread. This update is quite picture heavy, despite the fact it is really not of great interest in many ways! It also took place over the course of about 6 months due to parts lead time, and general laziness...

This update is thrillingly entitled 'boot refurb'. When I rust proofed the car when I first bought it, the boot had some of the most disgusting carpet in it, along with some surface rust. To stop the rust, I then did a very foolish thing. I sprayed Dinitrol underseal in there (after wire brushing etc). This was a mistake, brought about by too much time having passed and still not having been able to drive my new car.

Do not spray Dinitrol underseal in your boot. It is gross, and takes ages to get back out again. The following pictures tell a story (along with sloppy wiring, as I always intended to come back and do the whole area properly).

20210305_144214 by Jon Fellows, on Flickr

20210306_150138 by Jon Fellows, on Flickr

20210306_150141 by Jon Fellows, on Flickr

Lovely rust...

The first job was to clean all the black filth off. This took time, solvents, scourers and rags! After a good clean and the removal of the sound proofing, the boot looked like this:

20210309_094228 by Jon Fellows, on Flickr

20210308_104828 by Jon Fellows, on Flickr

20210308_104837 by Jon Fellows, on Flickr

After this, I applied rust converter and then a couple of coats of 2K epoxy mastic, which left the area looking much better and more tidy.

20210311_093523 by Jon Fellows, on Flickr

20210311_093536 by Jon Fellows, on Flickr

Next was replacing the sound deadening on the boot floor, and then a little on the side panels where the battery sits.

20210316_152735 by Jon Fellows, on Flickr

20210316_152728 by Jon Fellows, on Flickr

I also decided to clean up the fog lamp wiring. Being a JDM import, my car had no rear fog light. Instead of attaching one to the rear bumper, my car has had a reverse light repurposed. However, the wire for this bulb was a) too short so was pulled taught across the boot floor and b) hardwired badly to the bulb holder. I took the moment to extend the wire and route it properly, then put a plug on it to allow easy removal of the bulb holder board.

20210319_154251 by Jon Fellows, on Flickr

That complete, I then ran the amp wiring. The routing here looks a bit random, but the idea was to use the OE indentations in the pressed boot floor to hide the wires as much as possible when carpet went down.
This ended up looking like this:

20210319_160108 by Jon Fellows, on Flickr

20210326_102759 by Jon Fellows, on Flickr

I also routed the coilover adjuster extender through the fuel filler cover to allow adjustment more easily.

20210326_102748 by Jon Fellows, on Flickr

That done, it was a case of laying/gluing the new carpet set and fitting my new boot latch panel to finish off the boot.

20210626_150704 by Jon Fellows, on Flickr

20210624_171033 by Jon Fellows, on Flickr

And finally, all finished:

20220115_113415 by Jon Fellows, on Flickr

20220115_113353 by Jon Fellows, on Flickr

20220115_113403 by Jon Fellows, on Flickr

It took way longer than it probably should have done, but I'm pleased with the results now at least!

[Lewis's Friend]

jamieduff1981 said:

That's really very tidy looking! This car will be one of the best examples going, even without the Rocketeer conversion making it that much more appealing.

Thanks - I'm slowly going through it all as a lot of it was quite worn. The up side of that is I can make it my own. Next up is interior and very last will be paint I think.

shalmaneser said:

Wow quite the transformation! How many speakers does the amp drive? Would it be worth making a false floor to protect the amp when the boot is loaded up? Appreciate that may cut into boot space a bit too much!

Thanks.

The amp is just a 2 channel one, driving some Focal components. I have extra carpet and some plywood for a false floor, but I haven't got around to it yet - plus I was a bit concerned about heat dissipation from the amp so will see how much of a problem leaving it uncovered is.

[Lewis's Friend]

PushedDover said:

Nice job.
Getting v close to pulling the V6 trigger with Bruce for a full conversion. Anything I need to know / factor ?

Are you looking to get Basset Down to do the conversion for you, or to do a self build?

I would say the biggest thing with my version is now heat management under the bonnet. If I was to build it again, I'd look at coating the exhaust manifolds and any other method to keep heat down. Not for overheating purposes, as it cools well but to save power being sapped.

Also, my clutch can be a bit juddery due to heat after a long run (another facet of the above). I'm not sure if this has been solved, but I'd check that.

[Lewis's Friend]

MrBig said:

That looks great! Can I ask where you sourced the quilted material from please? I have a couple of interior jobs to do and that looks ideal. How easy was it stick round the edges of the door card?

Cheers for that. I think I bought it from 'I love fabric'.

It glued surprisingly well with spray adhesive, although I took the time to cut the padding material away from the surface so I glued directly to the faux leather when sticking the edges down on the rear face of the door card.

[Lewis's Friend]

PushedDover said:

Ah I am not brave enough, talented enough - or patient enough to do it myself - so a full turnkey installation having driven their demo last summer.
A little windfall has made it reachable.

I have the car under the knife at AutoBarn who have been doing an amazing resto (discovery!) and running gear upgrades (replacement in earnest as the car is 25yrs old). Itching to get it back and run it around, but am very likely to drop it off next winter for Basset Down / Rocketeer to do the turnkey conversion.
SO with that in mind - wont things like the heat management be included in the install?

That sounds like it'll be a lovely car when it's done. I only bought an mx5 so I could do the conversion t it, so have limited experience with the standard 1.8, but I found the engine to be disappointing - it didn't like to rev and felt weak (though mine was not a good example I think!). I feel the engine swap is perfect for the chassis though. No overwhelming torque, wants to rev but fast (though not exactly supercar fast).

In terms of the heat management, I would have that conversation with Rocketeer. I don't think they offer coated/wrapped exhausts as standard (though I may be wrong), but would be something I would consider. If I pull my engine for some reason in the future, I'll look to have this done.

The clutch I believe has been changed from my iteration to address the judder with heat build up, but again I would have a conversation about it.

There is a closed facebook group for Rocketeer builds which would be worth trying to join if you are looking to buy a car.

[Lewis's Friend]

A small update on my Mx5 - nothing too exciting, but a couple of little improvements...

For Christmas, I received a DaveFab jacking bar (this replaces the rear towing irons, and puts a bar between them that slightly protrudes under the rear bumper for jacking purposes - hence the name! While working in the area, I ended up replacing the rear exhaust heat shield too.

The heat shield I made was still in one piece, but I decided to buy the actual heat shield that I had blatantly copied before. This is because it's a bit more robust being of thicker aluminium, and I felt bad about my previous plagarism...

So - a new heat shield installed:
20220209_111157 by Jon Fellows, on Flickr

I then installed the jacking bar - this is very easy if the original bolts come out. If they don't, it's a pain! After much soaking in penetrating fluid, all the bolts got chugged out with my rattle gun which was a result. I cleaned the threads up on the bolts and captive nuts and could install the jacking bar.

20220212_110220 by Jon Fellows, on Flickr

20220212_110234 by Jon Fellows, on Flickr

Again, no massive changes but a little something to make getting the car in the air a little easier...

[Lewis's Friend]

PushedDover said:

Nice mod. Like that.

(I may have just paid the instalment for a blueprint AJ30 engine this morning.....)

Very nice! My engine is a breakers special - my idea was to get it built properly if it went pop at any point. But so far no issues so a standard breakers special it remains!

shalmaneser said:

The more I think about these V6 MX5's the more I think they're the perfect petrolhead car. You're doing a really nice job here, great to see.

Just over a ton in weight is a great achievement too, and it's hardly a stripped out build! It must get a proper move on.

I think it's a really nice combination of lightweight and power, but with nice linear delivery so it's like an Mx5+. I've never driven a turbo'd Mx5, so can't really comment on what they feel like, but I've always enjoyed the larger NA engines.

carl4x4 said:

Great build thread, I remember reading it before I bought my Rocketeer and staying up 'til 2:00am to read all of it :-) I finished my Rocketeer in November and have put about 750 miles on it so far with lots of 'improvements' and developments to try and make the car worthy of the engine! A quick question on wheels, I have a soft spot for the minilite replicas but my car is an '05 with factory sport brakes. They are a vast improvement on the old standard 1.8 brakes but do mean my wheel choice is limited. I'm currently running 16' mk4 wheels but would like the Rota RB's you have in 7". Do you run Sport brakes or normal 1.8? Lot's of conflicting information on Miata.net as the US Rotas seem to come in ET 35 and the UK ones ET30. I guess the only way for me to check is to try and bolt one on which is an expensive test!

I have normal 1.8, just with a fresh rebuild and EBC pads and discs. I don't know what they'd be like on track, but for road they've been fine so far - in terms of brake feel, the best mod I did was the DaveFab brake stopped. That helped a lot.

Not a very helpful post for you though I fear!

[Lewis's Friend]

carl4x4 said:

No problem, it's always good to hear what a fellow Rocketeer owner has tried out on their car. I would definitely agree on some sort of coating on the exhaust to keep temps down. I experienced too much heat from the right downpipe cooking the clutch slave cylinder and making it hard to change gear after sitting in slow traffic for more than a few minutes. Sorted that with a small aluminium heat shield. I have seem some people extending the air filters with flexi-hose to pick up air from behind the headlights which apparently drops inlet air temp considerably.

The biggest two changes to mine after the conversion that made a real difference have been the addition of frame rail stiffeners and changing to a 3.6 diff with the 5 speed. Without the frame rails you could feel the car wasn't happy with all the extra torque. The gearstick bucked around, the diff axle-tramped on hard acceleration, and the whole chassis seemed a lot more wobbly than with the old 1.6 ! I fitted the diff with void fillers for the bushes which helped a lot and tightened everything up along with the rails. Also with my old 4.1 diff gearchanges were over too quickly so the car sounded good but just seemed to be a faster louder version of it's old self. With much taller gear ratios it's transformed the drive into much more more of a GT where I can take advantage of the torque in all gears and not worry about frantic wheelspin in 1st & 2nd!

I know Mazda never made a MX5 with a 3.6 diff with 5speed as the gearing is slightly longer than even a 6speed with the same diff, but in the Rocketeer I'd recommend it to anyone doing the conversion.

I've just fitted void fillers as it happens, but not driven with them yet but am keen to see if they make much difference. I had no pictures, and it's not the most photogenic change anyway, so I didn't update the thread.

I'm also keen to fit chassis rails too, but that will probably be for the next winter period as I don't want to start that now as (hopefully) we move towards some better weather.

The 3.6 diff has been good, but 1st gear is over very quickly so I think shorter ratios would be a pain! I'm glad I fitted mine when I first had the car apart pre conversion.