Different MX5 engines?

[Skilfil]

Occasionally referring to Wikipedia when talking to friends and spotted a listing in the tech specs of a 1.6 with 88 hp? Link is below. Anyone know the story behind this?

http://en.wikipedia.org/wiki/Mazda_MX-5 ... ifications

[Angreal]

From memory (no idea how true the following statement is) in the UK they had limited the power on some mx5s. Well that's my story and I'm sticking to it until proven otherwise

[Euen]

There seems to be something extremely suspect about that table. They list the engine code BP-4W for both 1.6 and 1.8 engines from 1993 - 2005 but the BP-4W was only applied to the first of the NB 1.8 engines, from 98 in Japan but referred to as 99-00 in the US as there was no 98 MX5 in the US market. The 1.6 engines were all B6 and the 1.8s were BP.

[KSCRIM]

The 1.6 engine was detuned to 88BHP for Europe before the 1.8 was introduced. This gave a vast improvement in power for the introduction of the 1.8 engine, good for the advertisers. The 1.6 continued alongside the 1,8 in Europe (at the reduced BHP) and Japan.
The 1.6 continued in the NB up to 2005 for Europe (at 88BHP!!!!)and Japan, I've seen figures for the JDM 1.6 at 125BHP. From 98 on the 1.6 has better breathing and solid lifters in and out.

Yes the table is wrong for the 1.6 , it is always a B6 engine with various suffixes. The power figures are also suspect.

[Gravelben]

The 1.6 continued in the NB up to 2005 for Europe (at 88BHP!!!!)and Japan, I've seen figures for the JDM 1.6 at 125BHP. From 98 on the 1.6 has better breathing and solid lifters in and out.

Didn't the UK/Europe 1.6 get bumped back up to 115bhp in the Mk2 after the detuned 1.6 for the later Mk1?

[KSCRIM]

I've just found on the UK MX-5 owners club site that the 1.6 engines were rated at 110BHP in the NB's.
It seems that the power reduction happened in 1995.

I stand corrected

[Mark]

The BP-4W was only applied to the first of the NB 1.8 engines, from 98 in Japan but referred to as 99-00 in the US as there was no 98 MX5 in the US market. The 1.6 engines were all B6 and the 1.8s were BP.

AFAIK, there was no BP-4W in Japan.
Designation for the JDM 98-00 1.8 is BP-5A. Obvious differences are no EGR, different (4:2:1) extractors, different intake cam, different ECU, and 7500rpm red line.

[Euen]

Thanks for the clarification Mark. The 4W applied to the head and can be seen in the casting at the back of the head. The 5A designation is applied to the inlet cam which has it cast into the surface. I think I also noticed it yesterday on the exhaust heat shield on the 98 that Donovan is currently wrecking.

[Kieran]

I have a JDM 98 and all markings say BP-4W

[Mark]

I have a JDM 98 and all markings say BP-4W

Heat shield on the exhaust?
ECU?
Even a sticker on the radiator header is marked BP5A on mine.

[Kieran]

I dont have a heat shield but ill check the ecu

[Mark]

Thanks for the clarification Mark. The 4W applied to the head and can be seen in the casting at the back of the head. The 5A designation is applied to the inlet cam which has it cast into the surface. I think I also noticed it yesterday on the exhaust heat shield on the 98 that Donovan is currently wrecking.

I don't know if it's clarifying anything really
There seem to have been all sorts of variations between markets, significantly different exhausts, some with egr, different intake cam, different ecus, some with 7,000 rpm red line / 7200rpm cut-out, some with 7500 rpm redline / 7500rpm cutout (m/t). Not sure if the looms are the same, but if doing an engine transplant, using the ecu which came with the engine might be a good idea.