Air / Fuel Meters

[mroadsters]

I'm trying to decide what Air / fuel gauge to get.

I'm leaning towards an AEM gauge / wideband kit such as this one http://www.flyinmiata.com/index.php?deptid=4545&parentid=0&stocknumber=06-99110%20%20ALL%20COLORS

The other I see a lot of references to is made by Innovate.

Any comments or advice?

[Sam Powell]

That looks like a good deal, and should be a good product.I would trust the FM choice. I used the Inovate on my turbo Dart, and was happy with it but payed, I think, around $450 for that one.

The Inovate gauges have some hi tech features that were just a bit beyond me at the time. It seems there was an interesting flexibility in their design. For what it is worth, IIRC you can change the function of the gauge based on the input you give it.The gauge kit came with multiple faces for different functions. So one gauge can be changed over for another use if desired later. Also, I seem to recall that the Inovate gauges could be wired in series to simplify the wiring under your dash. I guess there is some practicality to that feature, but a standard single purpose gauge should work just fine.

How do you plan on using the information gained?

Sam

[mroadsters]

I'm running a supercharger + powercard with no idea really whats happening in there. Ignorance may be bliss, but it can also be really really expensive...

So If I'm lean, I'd like to know about it... And if I'm dumping too much fuel, that's something else I'd like to know about.

I think it's sort of related to shipwrights disease, but I was originally going to bolt on a SC and be happy, but as I've learned more about it, I'd like to learn more about it and perhaps get the most out of it.

[Sam Powell]

That sounds like a good idea. Have you heard pre-ignition? When I advanced the timing on my '97 NA to 14 degrees, it was pretty obvious when pre-ignition was there. I eventually set it back to 13 BTDC and it behaves better now. The point is, it was pretty obvious. Pre-ignition is the big engine killer with forced induction. Have you checked the plugs? Are you seeing flecks of aluminum on them? That would be piston metal if you are doing damage. What boost are you running? Have you had it on a dyno? What HP did you get?

Sam

[mroadsters]

Have you heard pre-ignition? When I advanced the timing on my '97 NA to 14 degrees, it was pretty obvious when pre-ignition was there. I eventually set it back to 13 BTDC and it behaves better now. The point is, it was pretty obvious. Pre-ignition is the big engine killer with forced induction. Have you checked the plugs? Are you seeing flecks of aluminum on them? That would be piston metal if you are doing damage. What boost are you running? Have you had it on a dyno? What HP did you get?
Sam

I get some pinging on tip-in from time to time. I'll be installing one of the Flyin Miata O2 clamps this week which hopefully will address that. Changing the timing on my VVT motor requires magical electronic boxes which I haven't got. I would need to retard the timing, but wouldn't want that across the board, so something like the Timing Card lets you make timing changes based on boost levels & RPM.

I've got an AEM AF gauge kit on order.

Plugs are clean. Stock kit is 5psi. No dyno opportunity yet, that would be interesting.

[Sam Powell]

Do you get pre-ignition under boost?

Sam

[mroadsters]

My only issue is a brief ( > 1 sec ) pinging on tip-in at low rpm - a fairly common issue with VVT cars from what I read.

[Sam Powell]

I would not worry about that. It is not going to destroy your engine, although it is annoying. That is pretty much when preignition happened on my 1.8 NA with the timing at 14 BTDC. If you are not getting pre-ignition under boost, that is a very good sign. Sometimes that can be hard to cure with tuning. Cam timing and compression ratio ends up playing a role there that tuning sometimes cannot work around.

The real horsepower is found through timing control. And, it is something only a few tuners are equipped to tune. A single pull on a dyno does not get you there. It must be a steady state dyno that allows the tuner to play with the timing under constant load and steady RPM while he bumps timing up. When the HP peaks and drops, he backs it off a point and continues on to the next cell in the map and continues until the entire map is idealized.

I know of no one in the area I would recommend to do your car this way. I thought John Behe was going to do this for my Dart, but he kept it 18 months and did nothing but yell at me for pressuring him.( I waited 8 months to start bugging him. So I could never recommend him in a million years. But, that is the idea you can go in search of if you want to get the best out of what you have.

Sam

[mph]

If you set up your car on a dyno you do not need the Air/Fuel Meter Kit

[Sam Powell]

If you set up your car on a dyno you do not need the Air/Fuel Meter Kit

This is true, but it is nice to be able to monitor it if you intend to do any tweaking of the maps later. It kind of depends on what kind of tune, and how much money you have to spend at the dyno shop. Also, If you have your own wide band O2 sensor, the shop that does the tuning will not need to charge you to install theirs.

Sam