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MX5 engine swap
JC - 14/7/21 at 02:08 PM

Hi all,

Idly considering an engine swap to MX5 power. Not wanting mega power, just an engine as standard as possible - 1.6 or 1.8.

I guess I would need engine, gearbox, engine loom, ecu. Would I need the dials to keep the ECU happy? Is there a nasty immobiliser to worry about? Thanks!

ianhurley20 - 14/7/21 at 03:13 PM

There are a range of MX5's so you need to know which one to go for. Mk 1 (NA) does not have a built in imobiliser Mk 2 (NB) has one as part of the system. Unless you change ECU you will need the car ignition key and quite a bit of the loom, ecu relays etc to get it running. I used all the switches, the speedo and instruments steering column and PATS system along with relays fuses - basically the lot.
Mk 1 UK 1.6 had 110 bhp when it came out but in 2004 (I think) emissions rules changed and power dropped to 88bhp. Mk 2 1.6 has 110 bhp. Import 1.6 Eunos has 115bhp throughout. 1.8 Does vary a bit in power but not so much 136 - 146 bhp from memory and later 1.8's have VVti.

Gearbox is an excellent item as 5 speed although a few have 6 speed boxes. Mk 1's have a mechanical cable drive for the speedo and Mk 2's an electronic sensor.

I've got a chart somewhere that lists all the variants but can't find it at the moment but a google search will probably bring it up.

I also used the front end of an MX5 propshaft matched to a sierra diff with the correct end welded on by a specialist.

The radiator fan works well on a VW polo/golf radiator

HTH

Tazzzzman1 - 14/7/21 at 05:39 PM

Be careful.... avoid a MK1 Import as these often had an immobiliser...ask me how i know

If you do then you will need the loom, ECU, Key and key aerial around the ignition barrel. Note you cannot defeat/ wire around the immobiliser

I used a MK1 1.8 and supercharged, using a CANEMS ECU, dual mapped at 180BHP for normal road use, and 240BHP for track/ mental use . Superb engines and gearboxes, and surprising cheap on parts

JC - 18/7/21 at 01:42 AM

Thanks Tazzzman - so for a Mark 1 MX5, I don't need the gauges to get the ECU to work. Good news!
Is the immobiliser just on the key, or does it tie into other systems?

Slimy38 - 19/7/21 at 08:41 AM

My Mark 1 import had an external alarm fitted, the ignition barrel had been butchered with several black wires going off to a terminal block. Once that had been backed out there was no built in immobiliser, although I am just using the standard ECU and clocks anyway.

Tazzzzman1 - 21/7/21 at 08:19 PM

quote:
Originally posted by JC
Thanks Tazzzman - so for a Mark 1 MX5, I don't need the gauges to get the ECU to work. Good news!
Is the immobiliser just on the key, or does it tie into other systems?



Correct the clocks are not required.
But if it does have an immobiliser then you will need both the aerial fitting which is around the ignition barrel and the key. Key, aerial, immobiliser and ECU are all tied in/ coded together. You can get around this obviously by using an aftermarket ECU (I used CANEMS) and no immobiliser

JC - 22/7/21 at 03:44 AM

Perfect, thanks for the help.

carboy0 - 13/4/22 at 01:00 PM