94/95 vs 96/97

[tnord]

well....that pretty much says it all.

curious which one i should be looking for. maybe one ECU responds to tuning better than the other, maybe it doesn't make a difference. but if i were looking for a 1.8l miata to build for ITA, which would be the better choice and why?

[Fastfred92]

A car I have considered as well, with all things equal I think the OBD I cars 94-95 will respond better to ecu mods, if you go the Motec route it will not matter, everything else is the same between the two..

[bldn10]

"well....that pretty much says it all."

Only in a world in which Miatas are the only Mazdas in club racing.

I guess next thing is that you guys will want your own Miata sub-forum. :lol:

[tnord]

yes yes, i realized my mistake after it was already up. i am referring to miata's here.

is the OBDI/II really the only difference between the two? no additional bracing anywhere, slightly tweeked injectors, larger AFM, or anything of the such goin on here? it's great if that's the answer, as it makes things much more simple.

[Crack Monkey]

According to solomiata.com, which is typically pretty reliable...
94-3/95 had 8.8:1 compresion ratio (though advertised as 9:1) and OBDI
4/95-97 had true 9:1 (due to taller dome on pistons) and OBDII

I'm not clear if the 4/95 date was a production date (and the cars were really 96s).

AFAIK, everything else that matters is the same.

Added pitcure (94 vs 96):

http://members.aol.com/solomiata2/94-96pistoncompare.jpg

[Andy Bettencourt]

The lower compression pistons came in early 94's. All 1.8 crate motors (94-97) that now ship from Mazda are identical, including the 9 to 1 slugs. The difference in power was the OBD-1 to OBD-2 move with tuning.

I would say the 94-95's are best for one reason and one only: Cost of donors.

[AntonioGG]

I believe the coil packs and MAF is different in the OBDII vs. OBDI. I don't know the significance of it.
Also, I think the OBDIIs add a crank sensor in addition to the cam angle sensor? I'm not 100% sure on that one.

Andy's correct, the early 94's (mine is one) with the lower compression pistons but you can replace those anyway (new piston supercedes the old, but I don't think you IT guys have that limitation anyway).

I've heard rumors that some cars came with better cams, etc. But I can't substantiate anything and you can update/backdate right? So I'd go with what Andy says and get the cheapest donor.

[Fastfred92]

I've heard rumors that some cars came with better cams, etc. But I can't substantiate anything and you can update/backdate right? [/b]


I have heard those rumors too, damn I wish I could find those cams :D

[Andy Bettencourt]

I have heard those rumors too, damn I wish I could find those cams :D [/b]

The 1.6's had no fewer than 5 cam profiles from the factory. The documentation is weak but the differences are minimal. I can imagine it is the same for the 1.8.

AB

[tnord]

different cams huh? this is the first i've heard of it.

i&#39;d love some more information on this. i know there are rumors around this division about some cams floating around that have netted 3whp gains, and have been found legal in tech.....i wonder if this has anything to do with it. <_<

i need to do some extensive research on just what the differences are between the 1.8 and the 1.6 besides the motor. i&#39;m tempted to buy a wrecked 1.8 shell and just swap everything over from the SM and start from there.