Talk to me about mx-5 engines.

[Disco Boy]

I'm talking specifically about the 1.6 engine on UK cars here.

My understanding is: the 1.6 (115bhp) was available on the mk1 from 1989 until mid 1993 when it was replaced by the 1.8

Then it was re-introduced in mid 1995 but it had been detuned to 90 bhp.

Then on the mk2 the 1.6 was 110 bhp.

So I guess my questions are:
Is everything I've said correct?
In what way was the mk1 1.6 detuned to produce 90bhp? Was it just a map or was it hardware? Either way is it possible to get those horses back?
Is the 1.6 in the mk2 the same 1.6 as in the mk1?

Also, what are the differences between mk2 and mk 2.5s? Is it just a facelift or is there anything else?
And which mx-5s have an LSD?

 

[saitrix]

Seems correct what you said there.

It is a hardware change that involve a lot of work, hardly know anyone who has bothered to do it.

Not sure on the 1.6 between mk1 and mk2, but I'd assume there will be small differences.

The 1.8's gained vvt with the mk2.5, not sure on the 1.6's.

 

[MeEsH BaKkA]

I currently have a 97 mk1 1.6 with the pants power, the late 1.6 engines have different cams (same cams as the auto 1.6s), lower compression ratio although not by much and a slightly diffrent ignition map. It is the cams which make the biggest change I picked up a set of early cams and dropped them in which has given me around 105bhp and the top end is much stronger.

The thing to remember about the late 1.6s they take boost better due to the auto cams having less overlap and the lower compression, you can pick up a used greddy turbo kit for around £500 for a nice jump in power. Also the late 1.6s come with the 1.8s larger brakes and rear diff which wont lunch its self at the slightest hint of increased power, the downsides are the 1.6 lacks the chassis bracing of the 1.8s but that can be picked up rather cheaply.

Im hoping for around 250bhp once I have got my turbo kit sorted out which so far is on course for costing me £800 due to using lots of second hand parts such as the td04 turbo (I have had refurbed) and the megasquirt management, the most expensive part of the build so far has been the roll bar, seats and harnesses (all new). So for a total parts cost of around £1200 I will have a 270bhp/ton fun machine. Good times.

 

[mk1_salami]

Pretty sure a few people have taken the base 90hp cars north of 200+

Not entirely sure what restricts them in the first place though.