Tuning help
 

So, I've finally gotten the Miata to a point where I can start to really work on the tune (THANKS BRAINY!)

I was hoping to get some feedback primarily on my timing, but hey, spotting anything would be awesome. FuelVE is just freshly auto-tuned, but hasn't been touched beyond that.

Difficulty: I'd prefer to tune for 91 octane on a stock 1.8 engine (94 with 8.8 compression). 92 is the highest octane I can get around here, and some stations only sell 91. ------- hippies! Carrying around toluene has 0 interest for me unfortunately.

Thanks so much guys, it really is appreciated!

see the timing maps hustler has for his, he tunes on 91.

Run Hustler's timing maps...when he has a low comp, built engine Brainy?

All right Brainy, start making fun of this map then.

I like what you did in boost, but I would have kept your cruise area the same, maybe bumping hte timing in that area that hustler has found good mpg cruising gains in .

Roger, thanks Brainy. I'll pull timing under vac, thanks.

you dont need more than 27-28° on your 100kPa row.

I run 16° at 200kPa on 93.


you now has benchmarks.

Oh shi...! Thanks again Brainy, benchmarks rock.

Just one last question for you then, Brainy.

What kpa limit do you put on EGO control? Is it fine to do it to the max kpa you expect to hit, or no?

No, put 90 as max load for EGO.

Okay, will do. Thanks Reverant! But...Why?

Homogeneous exhaust flow and "danger zone" why closed-loop alterations don't make sense.

Look at my little "pad" where spark is advanced, everything is else dropped:
https://www.miataturbo.net/attachmen...ine=1344691936

Do this. I don't know how your turbo changes things, but my 1994 at 9:1 compression made the lower PW with 15.4:1 AFR and 34* of spark angle. You're on your own for the rest. You can probably load-up my table and yank 5* above 101kpa and live to tell about it.

Suppose your wideband ages and starts reporting richer-than-actual mixture. The MS would pull fuel under boost. Boom.

Thanks Hustler! That helps a ton

Reverant, thank you. That explains a lot wrt EGO!

Now, time for a SERIOUS Hustler-esque question...

Guys, I can't get my penis out of...err.

I mean. Today, I went to set timing. I noticed serious timing jitter at 10* - changed fixed timing to 8* in MS, set timing to 8*, and timing was rock solid at 8*. Should I worry about the timing jitter at 10*, or should it be perfectly fine as is?

(Edit) A bit more. I've been taught that if you have a well running car, you should be able to hold a piece of paper near a car's exhaust, and it won't flutter much. The paper is violently fluttering, and a few times a second you hear a noise that is different than the rest of the exhaust. This noise is roughly in synch with the timing jitter.

I've used several sets of spark plugs to try to eliminate it. However, going colder only makes the noise worse and makes the engine go from shaking the car to violently fighting the whole car. Giving the car more timing makes it feel less worse. I've replaced the old coils with COPs, and this behavior is still there, although it runs more smoothly with COPs.

It's almost like I have one cylinder occassionally not firing or not fully burning, or occassionally misfiring. I'm not really sure of how to describe it, I'm getting a video of the car running now. This is something I've been struggling with for months, and if I get close to fixing it, the issue just seems to come back later.

WITH VIDEO AND SOUND! This is the least worst I can get it (Which is saying a lot, I can make it feel like the entire Miata is going to shake apart), and I cannot eliminate it entirely no matter what. So long as it does that random "popping", it's effing impossible to time at 10* - I get constant movement whenever it happens, not to mention AFRs going everywhere.

Are you running sequential fuel?

I've heard that paper-trick too. It doesn't work unless you have a cat and multi-chambered muffler to smooth things out.

Just for the sake of ultimate clarity, are you setting the timing calibration value to 10* or the spark table to 10*?

No, I'm on batch fuel.

Ah, I'm SOL then. Darn.

I'm setting it to fixed timing and working on setting the timing to 10*. The spark table is, I believe, untouched, so I guess I'm trying to set the timing calibration value?

I blame the rumble-idle to fuel on the walls. I can't help you with the dancing timing light. How does the car drive? Log spark angle and see what it looks like.

Isn't this a bad thing?

Sure, I'll go get a log as soon as I'm done with lunch here.