| This may be a stupid question (it's something of a habit of mine) but is the original 1.6 engine and the one in my '97 1.6 the same engine, but at different states of tune? And if so, how easy is it to tune mine back up to the performance of the early 1.6 cars? If the 100bhp per litre rule is true for most cars could all 1.6 MX5s be ported/tinkered and put out 160bhp? The idea of superchargers and turbos gives me the willies and I'm sure would kill me when it came to renewing my insurance. "Refining" a basic unit sounds much easier to explain to my insurance company. It would also be one less thing to go wrong would it not (assuming porting has no side effects). (12/99) |
|
.. 90 hp v 115hp 1.6 ... long argument .. never really resolved
here or at Billings .. I forgot! .. Interesting enough the UK Mazda workshop manual collection the dealer uses does not even mention it .. but then it scarcely touches on the 1.8. Just about any 16v engine under 2 litre will get to 100 bhp/litre if you throw enough money at .. the question is whether the torque characteristics are such that you could easily drive such an engine on the street .. not for nothing have Honda, Rover & Fiat developed variable valve timing. ... and there is a 1950cc Eunos in the UK .. in yellow .. with ABS (never a yellow option) .. it was sold by the time I found out about it .. a kit of bits to make such a beast is available.. official ones are 2004 last bit of gossip I had.. .. the porting I had seen in the dreaded Revs article reduced the valve guide support by 1/3 of it's length = 50% quicker wear ... so 50,000 mile rebuilds .. SP Performance do not do this (who the article was about). .. mention mods to any insurance company and it is an automatic 20-30% weighting .. after that the other 20% does not seem so bad :-) .. so N/A is possible .. it just costs more .. but probably has a nicer result (Werner!!) .. someone in US has a 200 bhp 1.8 ..it just cost them $17,000 .. I suppose this includes lots of dead ends and development .. but there you go. (12/99) |
| Getting more power out of the 90hp 1.6 isn't as easy as that! It's a VERY different engine to both the 115hp 1.6 and the 1.8 In the Phillipines they only have the 90hp engine and they seem expert on getting the best out of them. See http://www.miataphil.tsx.org for the club website and some of the nuttiest and friendliest guys around. You'll also see instructions for supercharging the 90hp engine! (12/99) |
| Further to previous mail on this - here's what I've found - largely on the Philippines club site, Jason Cuadra's site and links therefrom: The original 1.6 engine ceased production. The plan was for the engine size to change to 1.8. Largely at Mazda UK's insistence, a different 1.6 engine was reintroduced. Mazda were in deep financial trouble, and had to take the lowest cost course. So: The post-94 1.6 is: .a unit derived from a later normally-aspirated B-series, not the modification of the B6 Turbo which the first (1989-93) 1.6 was. (The later engine came from the standard 1.6 323) .Different combustion chambers .Smaller valves .Different camshafts (less aggressive valve timing - 10 degrees less opening) .Rev limiter at 6750 rather than 7250 .Less crank case stiffening .Probably less efficient porting .Probably no piston-cooling oil sprays. .Different ECU In the Philippines, they run without O2 sensors and cats. No info on how the ECU doesn't go into failure mode with no O2 sensor input - obviously something has been done. The UK cars must have cats and O2 sensors? Jason's effective tuning efforts included: .Timing (14 deg) +6hp .K&N cone air filter +5hp .Free flow exhaust system +4hp They (Philippines) have also supercharged the engine (Sebring) - but beware - whereas the original engine was designed for forced induction and is therefore (reasonably) reliable with it, the later engine was not, and may suffer.. (9/00) |