ThunderFox

I'm looking forward to improve my ignition. I've had my car dynoed a few days ago and achieved poor results. Only 109hp! :(

I know I'm running a conservative ignition map, but I figured I wouldn't have such an extreme power loss. I'm daily driving my car on 95 octane RON (that should be the same as your 91 octane in the USA?).

I'm posting my ignition map for you. If any of you guys have any idea where my ignition should be at, just give me some input. Meanwhile I'll get some det cans to fine tune from there!

I want to keep the ignition at safe levels, so I don't really know the limits I can push it to.


(91 Miata on stock 1.6 engine by the way.)

bcrx7

iTrader: (5)

Ok so you have a stock 1.6 and this is on a chassis dyno? You should be happy you got 109hp if that is to the wheel! I mean there is not much you can do with the stock 1.6 leaving it N/A!

ThunderFox

To the wheel? I wish! It was 109hp estimated to the engine, I actually made 68.3rwhp!

I know enough to know what kind of gains you can expect from an NA tuned engine. My car has a full 2" cat-back system with no catalytic converter, no MAF, the intake has been redone with a carbon airbox, so I was well expecting around 120hp. The car was also dynoed on 98RON fuel.

I've double and triple checked my tune, even the dyno plot is flawless. The only thing still left untuned is the ignition. It's either this or the engine needs a rebuild.

In any case, I'm looking for some tips on where to improve this ignition tune, without of course risking detonation... Any idea what the safe levels are? Ideally, I wish I could get my hands on the stock miata ignition map.

sixshooter

iTrader: (12)

If you increase the spark timing to around 29 or 30 degrees from 4000 RPM up to 7000 in the 101 KPA row you will achieve maximum horsepower. Those numbers are from a spec miata car builder. You should use the det cans to ensure no knock under load at those levels with your fuel. If no knock with those numbers, blend the numbers below the 101 kpa level to make the transition smooth.

109 wheel horsepower is pretty good for a 1.6 liter Miata engine if that is uncorrected numbers. Make this adjustment, check for knock, and then see if horsepower improves.

ThunderFox

Thank you very much for your input! Like I said, the actual values were 68rwhp, we don't usually measure horsepower to the wheel here. We measure in estimated engine horsepower (rwhp+drag) and that value was a corrected value by DIN70020.

The actual power measure was 106bhp / 68rwhp, no corrections. That is why it is strange.

sixshooter

iTrader: (12)

It looks like there is a computational error made by the dyno operator. I would try a different dyno for comparison.

Braineack

iTrader: (62)

close enough.

Leafy

iTrader: (1)

If you're N/A your top ignition cell should be 101 kpa. All the cells above it are useless. Use it to get yourself some more resolution. The FM hydra basemap uses timing numbers in the 40s btw, and I still haven't had that car on a dyno to adjust them but I'm not running into any knock with that and smooth consistent afrs. This is on a 1.8 but the combo chamber shouldnt be all that different. You need to be on a load varying dyno and be watching/listening for knock to tune spark properly though.

Braineack

iTrader: (62)

which is wrong.

OPs WOT row is pretty much ideal, might be able to get a few more degrees worth of power.

going higher than 40 in the cruise rows is silly.


if he dynoed at 68.3rwhp, then he has MUCH BIGGER issues to worry about than squeezing a bit more power out of it.

Leafy

iTrader: (1)

I thought 40 should be well above mbt. I didnt think our cylinder heads could suck that badly.

ThunderFox

Care to explain which bigger issues those are or could be?

I don't think the drag measured values are that off, a friend's NB was tested the same day at the same dyno and he put out about the same drag values. His 110bhp NB was dynoed at 118bhp, so if anything, that dyno was being optimistic... I don't even want to think about that!!!

Braineack

iTrader: (62)

do you have the ignition still locked from initial timing adjustments??

ThunderFox

I set it to -10 (use map). Trigger angle is at 65 and addition is at +22.5.

However I will say that I haven't checked the initial timing as I am yet to get a hold of a timing light. I just assumed that since it was set on the stock ECU and these maps are pre-made for an MX5, it couldn't be too far out of point. Hence why I haven't fiddled with my ignition map yet.

This does leave me wondering though, if my timing could be so far off as to cause all this loss!

soviet

iTrader: (10)

yeah......................................
I'm guessing your timing is completely fucked up. get a timing light and fix it.

ThunderFox

I'll see if anyone can sort me out a timing light... Hope it's that simple!

Oni

iTrader: (1)

call me crazy, but is 69rwhp really that bad from a 20+ year old engine that originally only made 80 rwhp odd? the mods might have made a bit of difference but the 10-15% less than factory HP id have just assumed was due to 20 years of wear.

Braineack

iTrader: (62)

ThunderFox

You'd be surprised how hard it is to find a timing light... None of the nearby shops have one, and I've called a few car part dealers to no avail.

Oh boy, it will be a long run :(

Leafy

iTrader: (1)

Harbor freight has pallets of them.

ThunderFox

What's a harbor freight?