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Does anyone know where you can buy std 10:1 pistons for an NB8B?
(Besides spending an arm and a leg for genuine Mazda)

Every supplier I've spoken to seems to only stock the 9.5:1 ones..

mx5gem wrote:Does anyone know where you can buy std 10:1 pistons for an NB8B?
(Besides spending an arm and a leg for genuine Mazda)

Every supplier I've spoken to seems to only stock the 9.5:1 ones..

Did the pistons actually change or was the compression ratio increase due to the new head?

I'm sure you can get a supplier to custom make pistons to whatever CR you want.

I do not know the answer but given changing pistons is no small task giving rise to questions like whether the bore needs attention then taking a short cut with suspect quality pistons and rings is questionable. Seems a little odd that Mazda actually stock a piston set higher than standard?? An increase in comp may itself do little and maybe locks in 98 RON? Would the ecu need adjustment or does it adjust itself?

Matty wrote:Did the pistons actually change or was the compression ratio increase due to the new head?
I'm sure you can get a supplier to custom make pistons to whatever CR you want.

The pistons changed, (extra dome) to give the 0.5 bump in compression

Mr Morlock wrote:I do not know the answer but given changing pistons is no small task giving rise to questions like whether the bore needs attention then taking a short cut with suspect quality pistons and rings is questionable. Seems a little odd that Mazda actually stock a piston set higher than standard?? An increase in comp may itself do little and maybe locks in 98 RON? Would the ecu need adjustment or does it adjust itself?

They are not higher than std, The NB8B std comp ratio was 10:1. I am just after stock NB8B pistons to put in my NB8A block, giving a 0.5 comp bump.

The engine is in pieces now anyway, so while there I thought it a good time to throw in some 10:1 pistons for a minor perf improvement, seeing as the costs are small compared to the cost of the entire rebuild. (eg a choice of 3 or 4 aftermarket suppliers for NB8A pistons all at a fraction of Mazda prices, yet no sources for NB8B pistons... meaning Mazda stealer prices )
I understand I can get custom jobbies done, but seeing as all I am after is stock pistons I thought there should be a cheaper option..

I always run 98 anyway, already have a piggyback ecu, and my thinking is that while its apart and I'm only doing an otherwise std rebuild I could put the higher comp pistons in, seeing as a few years down the track when I want some more power I only have to take the head off to port, cams, etc rather than do the bottom end again..

lots of non genuine 10.0:1 pistons out there. why buy overpriced genuine ones.

project.r.racing wrote:lots of non genuine 10.0:1 pistons out there. why buy overpriced genuine ones.

Do you have any details on them and where I can get them?

hang on, you have a stock 10:1 engine, and you want 10:1 compression, why dont you just keep your pistons when you rebuild?

Dann

NitroDann wrote:hang on, you have a stock 10:1 engine, and you want 10:1 compression, why dont you just keep your pistons when you rebuild?

Dann

I have a stock 9.5:1 engine (NB8A) so while the engine is apart anyway I want to put in the 10:1 pistons from the NB8B

Ah i see. Just get it shaved.

Save yourself the hastle of purchasing new pistons when yours are fine and you can just shave the head for cheap as.

Dann

http://949racing.com/supertech-pistons-miata.aspx

949 still have the 10:1's listed still. Couldn't you just get a good set second hand set from a stock motor NB8B and put new rings on them? You could potentially pick up a fine set dirt cheap as anyone that's upgraded would have them lying around. I know I'll have a set I won't want by the end of the year for instance that I'll have no use for. Alternatively if you got a set out of a JDM engine the NB8A was 10:1 and NB8B was 10.5:1. Personally if I was upgrading I'd just get 11:1's.... stock ECU runs on the rich side and I know at least one person running them without grief on a stock ECU NB8A.

mx5gem wrote:

project.r.racing wrote:lots of non genuine 10.0:1 pistons out there. why buy overpriced genuine ones.

Do you have any details on them and where I can get them?

search wiseco / je / supatech + miata on ebay. with the usd vs aud being so good. you'll pay under $600 for new forged pistons from a us supplier.