Is just an Air flow ratio gauge enough for tuning an Apexi S-AFC?

I've heard they are horribly inaccurate.

The other method I know of is EGT. Which would require tapping into the down pipe etc.

Another question: What are the appropriate temperature ranges on a turbo rotary for lean, stoich and rich? and what air flow ratio's apply to what temperature?

I need to get my S-afc tuned asap so i can get it to a dyno. Thanks.

-Mike

 

EGT guage is good but its response to change in temp = is not instant, the best way to tune it and the best way to tune anything is with a widebad o2 sensor.

 

Unless its a wideband, no. EGT would be good if you know what the numbers your looking at mean as far as tuning it, but your best bet is a wideband on a dyno. Lots of dyno places will have a wideband you can just tune with then just keep an air/fuel gauge to get a decent idea of if your running way to rich or lean.

 

I need to drive the car to a dyno. Right now it's acting a little wierd with the S-AFC in place. it's sitting at about a 2k idle. and then bogging. There isn't any vaccum leaks i can tell of because it doesn't die out and I don't have to keep my foot on it to keep it running.

 

It's air/fuel ratio, and no, they're not suitable for full-load tuning unless you have previous experience doing it and a fair amount of knowledge on tuning.
Not entirely true, but in this case it's not accurate enough.
Other way around actually. You need to get to a dyno ASAP to get the S-AFC tuned.
This is not a tuning issue. If you install and configure the S-AFC correctly, and leave all the fuel correction settings at zero, it should run exactly the same as before. If you've upgraded the injectors you can apply an appropriate correction figure across the board to make it run normally.

 

I've upgraded the injectors to 720cc low imp injectors. All wires are soldered in place according to the series 4 wiring diagram.

I get Air/fuel mixed up with Air flow pretty easily so please excuse any mistakes

Also:

I bought this S-AFC used, will it still have all the settings resident from the previous user? And if I "Intialize" the unit will it reset them back to the base line?

 

All four or just the secondaries? If it's all four, then set all fuel correction points to -24%. If it's just the secondaries, then set all points above 3800rpm to -13%. This will make the car drive as if the stock injectors were in place. Drive to the dyno and have it tuned to optimise power.
Yes and yes.

 

Yeah it's just the secondaries, and thank you very much for the information.


What should it be below 3800? -24%?
-Mike

 

Below 3800 should remain zero because the secondaries wouldn't be functioning befor that.

 

Correct. Only the stock primaries will be firing before then, so no correction is required.

 

Ok results for monday: Initialized AFC, turned key completely off, then back to on. Set points up to 4000 at 0% and 4000 and above to -13%. Also Adjusted TPS. to 1volt while key is at on position. It was previously 1.575. The smoking issue was too much premix in the gas. I've diluted it to the correct ratio now. Ok, the Weird part is that when I start the engine, Idle goes directly to 1000 RPM then grows steady up to 2000 RPM, then if I put my foot on the gas it will go up to whatever RPM I want, but it will not decelerate when I take my foot off the pedal.

EDIT: I should mention it was doing the same thing prior to adjusting the TPS / Initalizing however, if I let it sit at 2000rpm it would eventually start to drop down to 1000 RPM.

 

Any idea's on this problem?

 

Did you adjust the tps when the car was fully warmed up?

 

NZconvertible, do the secondary injectors have anything to do with the 5/6th ports opening? Will the secondaries activate @3.8k regardless if the ports of functional or present? I would really like to know.

 

It wasn't fully warm no. It was about half way, it didnt' seem to help or hurt the problem however so I don't know how much bearing it has on the situation.

 

 

I'm going to check into an issue with the throttle cable being fowled up. This maybe the issue.

Thanks

-Mike

 

Nope.

Yep.

It's very important that the engine is fully warmed up of the thermowax will affect the TPS's setting.

 

Yes, I concur NZConvertible, important it's fully warmed up.
But not always 1/2 way up the guage, especially if you have a S4 like I think you do, f1blueRx7?

S4's are generally only 1/4 way up the stock temp guage when they're at operating temp.



(ps, yes, sorry, I know you pedantic english basterds I know I used 'but' at the start of a sentence...)

(pss, just thought i'd add that tidbit about the temp guage incase there was any misconception about where fully warmed up actually was.. Please forgive my intrusion if there was no misconception.. )

 

I've got oil and water temp gauges so i can measure when it's hot.

And yes it's an s4, and I've done the TB mod quite some time ago, would that effect how long it needs to get warm?

 

If you've removed the thermowax then engine temp doesn't matter when setting the TPS.

 

Ah ok. Thanks.