ecam8000 wrote:The helmet thing was mostly a dig at RX7 Chris. I voted other as well. Find a 1.8 and build it over time. Build it strong but not high strung. Run it N/A while you assemble the turbo. 250 Turbo HP with little weight vs V8 torque. Don't get me wrong, I love the idea of a V8 Miata, but for me the Boosted Miata at this altitude and with good mileage when driven mild, a good recipie!
I guess I wasn't privy to the inside joke, haha! At this point, after doing a bit more research, I think building a 1.8L for boost seems to be the way to go without spending a ton of cash. A set of low compression forged internals and a decent sized snail will likely be the route I choose. Although, I'm going to reserve final judgement until after I get a couple rides from local turbo & V8 guys.
chickenwafer wrote:It's funny you mention knock because the knock sensors Mazda uses on most rotary cars are such a joke I completely turn them off because they'll employ their correction factor at random times and pull timing when they shouldn't, and then when slight knock occurs (most rotaries don't survive "real" knock) they don't do shit. I've noticed the FD knock sensor is a little more sensitive but holy shit the RX-8 knock sensor was a complete joke.
Most standalones you can wire in a knock sensor to employ a correction factor to timing if you wish. I know the AEM I had for my FD did this.
That's funny (in a not-so-funny-way haha). On most Subaru's, most people (including myself) actually adjust the factory knock sensors sensitivity levels to make them more sensitive, and they do a decent job. On pump gas on my old STI, every once and a while I would see my IAM go below 1 (applying knock correction in a certain range) and on rare occasion, on a hot day, flogging on the car would result in a knock count or 2 (rare, but it happened). Although, on E85, my IAM never went below 1, and I never logged KC regardless of conditions.
Which, allowed me to tune the car the way I like to tune: keep adding boost/timing until you hit MBT! I prefer the torque curve to stop me from tuning rather than having to dial back timing advance a couple degrees due to reaching the knock threshold. My Bimmer actually has 4 knock sensors, and many speculate that they're "overly sensitive" (I've seen plenty of timing drops in stock form), which is common, but people do things to these cars that would result in popping a Subaru motor in a heartbeat (blind 25% increases in load without allowing the ECU/DME to see/compensate for the increase in load, relying on the knock sensors to adjust timing), and the funny thing is, it's incredibly rare to hear of a popped N54 motor regardless of what idiotic things people do to them. Although it is difficult to know if they're experiencing a major knock event, as the ECU/DME applies cylinder-to-cylinder timing corrections, so logging timing advance on one cylinder doesn't really say much about what the other cylinders are doing (no EM solution for the N54-Cobb AP, Procede, JB4 ect-can decipher knock sensor data accurately/too many sensors, so "knock" is generally "measured" via timing drops).
What's funny is that even while seeing *3+ timing drops regularly under full load (assumed knock), the plugs look fine, and compression/leak down test results always seem to come back fine on these motors (N54). These ECU/DME's are sick. As a tuner, if you played with one, you would be amazed I'm sure.
However, Cobb claims it took them 6 times longer to crack this DME than any other ECU they've ever worked on (including the Mazdaspeed ECU's & GT-R ECU), and flashing them with an AP initially takes ~20 minutes (compared to ~5 for a Subaru haha!), as there's a TON of data on them/more tables than I've ever heard of an a factory ECU. I won't lie, I do like their compensation tables & they fact that they actually have a targeted torque load. Sorry for the rant/novel, but as a tuner, I think you would like playing with these cars.
I actually already started looking into Standalones for the Miata, and was planning on running the MegaSquirt for ease of installation & use (PnP & interface seems to be pretty intuitive). I'm assuming it will accept knock sensor input, but am still researching... if not, I know the Link ECU's will accept an aftermarket knock sensor, so either way, there are choices. One thing I'm keeping in mind is that the NB Miata's come plumbed with a knock sensor stock.... that, combined with the fact that they have a better flowing head is something that is making me consider picking up a 1999-2000 block to build up (2001+ have VVT/more complex, I'm hesitant).
Either way, it should be an interesting experience.
rugger wrote:I forgot the fuel system, too. I have a couple hundred (at least) in it.
Hell yeah I'll take you for a ride. It really is a blast. My 327 is putting down 300+ hp/tq, and I can't wait to finish building the 400 for it. It will be a bolt-in swap, and I should have 400+ hp/tq to the wheels......before the 150 shot.
Hell yes! Sounds like a beast
erod550 wrote:Yea I don't even want to add up all the little things I've spent on my Miata because I'm pretty sure I have over 5k in it and it's still basically stock. :\
As for a built 1.8L costing more than boosting a 1.6L, you'd only have the cost of the 1.8 to begin with ($400-700 depending on mileage), and then the cost of the internals (probably about a grand). Other than that, the cost is going to be similar to just boosting the 1.6L, and you'll get a lot more power out of the built 1.8L (with higher boost). I don't know though, being able to break the rear end loose at 2500rpms with a V8 would be a lot of fun too, heh.
I just barely bought the car for $2200, and have probably spent close to $2000 on top of that already, just getting the car back up to par.... it adds up quickly, and I haven't even touched the motor yet, haha!
Honestly, if I'm going to build a 1.8L, I'm likely going to just pick up a 1999-2000 longblock (might as well get the better flowing head while I'm at it), so it will be a bit pricier, but I'm sure I could recoup some cash by selling my 1.6L when I'm done, but I get what you're saying, and agree with you. Although I'm sure I would prefer the throttle response/torque curve of the V8 over a turbo 4, but am not sure it would be worth the extra cash to me. We'll see I suppose.
