EErockMiata

Stupid question from my own paranoia incoming.

When I had the OE bp4w in my 99 on the stock ecu the rev limiter came on at 7k indicated on the tach. Now that I have my vvt motor in the car on ms3 with a 7200 hard limiter the rev limiter kicks on at 7200 indicated (confirmed via data logging in the ms3)

1) what was the rev limit on the bp4w? I had no way of getting a measurement when I had that setup.
2) is 7200 a relatively safe/conservative track car redline for an NA vvt motor car? I will say that the motor takes on a different hum and resonance in that last 100ish rpm before red line. I rarely hit it as I try and shift at 7000-7100 but its nice having it there for certain straight always.

Just looking for some opinions here in the realm of, if this were your car and you had a very healthy junk yard lottery long block, what would you do?

Leafy

iTrader: (1)

At the very least the JDM/EUDM 01+ motors are NB heads because the flatops manifolds fit the NB head.

18psi

iTrader: (76)

nope. ok now I'm really gonna look for that thread.

concealer404

iTrader: (3)

Actually BP5A has to be NB head because it has VICS manifold.

Monk

iTrader: (3)

I just asked the guy selling this if he knows:
99 00 Mazda Miata MX 5 1 8L DOHC Engine 6SPD Transmission ECU JDM BP5A BP 5A BP | eBay

emilio700

iTrader: (3)

JDM/EUDM/USDM NB engines all use the same castings. NB1 has a different piston (.5 more cr), and the 5A intake cam. NB2 has teh square top and .5 more cr pistons and the little mass damper on the TB. I have crosschecked just about every part in both against USDM and those are the only differences.

What's interesting, particularly in the case of the NB1, is the 7500 rev limit the JDM variant gets. It's no different than ours and we recess valve seats if we do that for a bout 6 months on a stock NB1. The conclusion is not that the JDM has secret sauce, but that Mazda knew they would not be driven as much as a USDM car and was OK with the accelerated wear for their home market. Mazda has never been an "engine company". Honda would have given the JDM variant better parts for an actual improvement but then failed by sticking it in a wrong wheel drive mobile.

18psi

iTrader: (76)

wow, so the other thread is way wrong then.

ok well I need to save this post to avoid confusion later.

Thanks for that Emilio, very helpful.