Blayton

Hey guys, I recently re(built) my motor after turning my stock rods in to bananas. I bored it over .040, put Supertech 84mm 9:1 compression pistons, and Manley rods. I'm very aware of the fact that lower compression means that you can get away with more timing. But I've had trouble finding a general idea of what my ignition table should look like with the new compression ratio. I am running Lars's MKTurbo churbo still. EBC is set up for 212 kpa or 16psi currently. Anyways, I wanted to get some more educated and knowledgable opinions on my current map. In my opinion it is pretty conservative accross the board, but then again there are some posts that would contradict that.

Thanks,
Blayton

18psi

iTrader: (76)

That looks fine. I'd probably start with a touch less in the 137-157 rows.
Biggest impact on "safe" will be the fuel you use, which you haven't mentioned.

Blayton

Fuel is pretty dialed. 14.7 cruise, tapering to 11.5 in boost, low 15s highway cells. My main concern was if I could get away with any more timing safely. This map is almost exactly the same map I used with the factory 10.5:1 pistons, with an exception on a couple degrees up top. I would have it Dyno tuned by a professional, but idk how long I'm keeping this little baby turbo.

18psi

iTrader: (76)

I meant Fuel quality

As in, which octane, and the actual quality of it (not all even same oct rating fuels are actually same)

Blayton

Wow, I completely read that wrong. My bad. I'm using 93 octane, usually from Sheetz, because it's closest. I've heard that Sheetz gas has more ethanol than other stations, but I'm not sure the effects of that.

18psi

iTrader: (76)

Well then in theory you should definitely be fine.
but only a dyno and det cans/knock sensor would be able to 100% confirm

Blayton

Ok. Is the OEM Miata knock sensor (on a vvt motor) a good indicator? I've read conflicting opinions about them. But in my datalogs, the knock % never exceeds 5-6%. What percentage would be high enough to worry?

Bronson M

iTrader: (1)

The best way is to set a baseline of noise which should increase as rpms increase with a known safe tune. Then set your threshold slightly above that. I'm experimenting with a knock limit 5 to 10% above baseline. Mine starts out at 5% and goes up to 15-20% at redline with a safe tune. Just have to get on a Dyno and get my Det cans working to verify when knock really does happen.