87RXGhey7

I think its time for me to properly tune my safc and I dont want to go to the dyno. I was wondering if it is possible to buy a universal air/fuel gauge and hook it up w/ no problems. Or do I have to buy a special one just for the rx7. Merci

1987RX7guy

iTrader: (3)

Do NOT try to tune an AFC with a guage. The guage reads off of your narrow band O2 sensor and is not accurate enough to tune at all. You need a wide band sensor or egt guage. Preferably on a dyno so you do several identical runs to make sure what your numbers are.

Santiago

87RXGhey7

Im too cheap and Im crazy

1987RX7guy

iTrader: (3)

In some great words I have see on here: "Speed cost money. How fast can you afford to go?"

I am not telling you that you can't do it. You can but I wouldn't risk a 1500 dollar bill on cheapness.


You said properly tune your AFC. A guage is not PROPERLY its ghetto.

87RXGhey7

how will an exhaust temp guage help?

87RXGhey7

Ill answer myself: With an EGT gauge monitoring your exhaust temps you can observe and be forewarned of potential leaning-out problems leading to catastrophic failure due to excessive engine temperatures. When you're engine is running lean (a high Air-Fuel ratio), the combustion temperatures climb dangerously high. If not corrected it will likely lead to "holing a piston." This is when the cylinder wall essentially melts.

Travis R

I would say that a regular O2 sensor and generic gauge would be better than nothing... but you really need a wide band O2 sensor to get it right. Stock O2 sensors are only valid right around 14.7, the gauge will only be able to tell you if you are above or below this number... but not by how much.
Good luck

87RXGhey7

what temp should I be looking for w/ pryometer?

1987RX7guy

iTrader: (3)

There are some good threads on EGT readings for TII's I don't know about N/a's though.

I would say just get one of those DIY wideband kits and make it for half the cost of a pre-made one. I think we calculated it to a total cost of around 380 dollars. But you have to know how to solder and stuff so it might not be for you.

Honestly dyno tunning is much cheaper than buying guages and sensors man. I hear its around 100 dollars an hour. I don't think you would need more than 45 min. Most dynos have a wideband that you can borrow for tunning.

ilike2eatricers

yea paying $100 for an hour of tuning without having to buy any gauges or wideband o2 sensor is alot cheaper and safer than tuning it yourself in the long run. A blown motor due to bad A/F ratios is pretty expensive and can be definately avoided.

87RXGhey7

hmmmm....good idea
Im going to the dyno
bye

rx7_turbo2

Nope

If you compare a standard A/F gauge to a wideband you will see that the standard A/F is actually worse than nothing. The readings are misleading and false.

I have seen on a whole number of occasions the autometer gauge reading full rich, when the wideband says 15:1, now that's just scary.

As for the EGT, I'm not a big fan. It can tell you how your timing is set up, but it reacts WAY to slowly to give you an idea of the A/F ratio. At least for the rotary motor.

This has been said by very knowledable people but it needs to be said again. THE ONLY WAY TO PROPERLY TUNE IS WITH A TRUE WIDEBAND O2 SENSOR PERIOD.

87RXGhey7

ok, I have an appointment tonight for the dyno, I only have one hour on the dyno, so can you tell me the easiest way to tune it myself timewise.

rx7_turbo2

You would always rather be rich than lean. So go through your SAFC settings and bump the fuel up. Then do a run on the dyno. Get the operator to plot on the graph your A/F ratio. Look at the chart and where the car runs rich go into your SAFC settings and lower the fuel 1 or 2 points, in the area's where you need more fuel, raise the settings a few points. then do another run, look at the graph again and adjust the settings. I would have booked it for more than an hour.

A few things to remember.

1)Start off real rich
2)Pull back fuel in very small increments.

87RXGhey7

how long do you think it would take?

rx7_turbo2

Everytime I've been to the dyno something comes up making the stay longer. I would say to tune it would be a couple hours provided nothing goes wrong. You have to set the dyno up and fiddle with it a bit first, that always takes some time.

ilike2eatricers

It should take less time with an NA right?

rx7_turbo2

In theory? Yes.