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-   -   Setting the A/F ratio? (http://nissansilvia.co.uk//showthread.php?t=1974)

alundra 10-03-2007 01:22

Setting the A/F ratio?
 
I'd like to set my air fuel ratio.

My mods:

MK 1,5
Stock ECU management, stock injectors, K&N filter in box, 2.5" piping+ intercooler, polished head, cold spark plugs, T2 at 0.6 bar with MBC, 2,5" exhaust, 98 RON, Luk 13 clutch, 40 mm dropped etc...

I have a digital A/R ratio gauge, idle 14.6, full throttle/full boost 10(can't read under...). i'd like to set up like 12.5/13 at full boost.

What can I use? (cheaper to higher cost)

Cheers.

Maximilian 10-03-2007 10:44

Apexi SAFC-II, can't say much about it but i know there are several writeups for using them on the S12 CA18ET.

alundra 10-03-2007 13:15

Thanks for reply:

Who test this?

http://www.hksusa.com/categories/?id=1920

s12Rob 11-03-2007 09:01

Quote:

Originally Posted by alundra (Post 15736)
I'd like to set my air fuel ratio.

My mods:

MK 1,5
Stock ECU management, stock injectors, K&N filter in box, 2.5" piping+ intercooler, polished head, cold spark plugs, T2 at 0.6 bar with MBC, 2,5" exhaust, 98 RON, Luk 13 clutch, 40 mm dropped etc...

I have a digital A/R ratio gauge, idle 14.6, full throttle/full boost 10(can't read under...). i'd like to set up like 12.5/13 at full boost.

What can I use? (cheaper to higher cost)

Cheers.


how are you running a air/fuel guage?

30psi 11-03-2007 09:13

I've got a a/f gauge:

http://img.photobucket.com/albums/v2.../DSCN1145s.jpg

The best way to alter the fueling, is to remap the ECU.

Alundra why don't you turn the boost up (if the turbo allows) and see if it reduces to say 11.5:1.

The reason why they run so rich is because they are mapped without an intercooler ie they make it rich to run safe

s12Rob 11-03-2007 10:00

how much did that kit set u back and is it for sale, lol

Wocketfast 11-03-2007 10:52

Im struggling with this right now as well. I have a dash mounted A/F gauge but it lies to me through the medium of flashy LEDs :trout If you turn all the accessories in the car off then at idel it shows rich, but if you turn the lights and fans on then it nearly shows lean? is this strain on the engine via the alternator, or is it that the voltage supply to the meter should be regulated at 12v :confused:

Im thinking of visiting a tuner to see if they can get my car back nearer where it should be but the only adjustments would be the AFM, throttle bypass valve (idle) and the timing. Would this be enough to set teh car up better than current :confused: (it cant get much worse)

Currently running about 20p per mile! or about 21mpg. I would really prefer 25mpg which would be about 17p per mile or a saving of £372 per year (so I can spend that much making the change and be no worse off. My bluebird turbo (same engine,heavier car, intercooled, more restrictive exhaust) was <14.5p per mile or 29mpg so it should be achievable.

sideways danny 11-03-2007 11:59

Quote:

Originally Posted by Wocketfast (Post 15797)
Im struggling with this right now as well. I have a dash mounted A/F gauge but it lies to me through the medium of flashy LEDs :trout If you turn all the accessories in the car off then at idel it shows rich, but if you turn the lights and fans on then it nearly shows lean? is this strain on the engine via the alternator, or is it that the voltage supply to the meter should be regulated at 12v :confused:

Im thinking of visiting a tuner to see if they can get my car back nearer where it should be but the only adjustments would be the AFM, throttle bypass valve (idle) and the timing. Would this be enough to set teh car up better than current :confused: (it cant get much worse)

Currently running about 20p per mile! or about 21mpg. I would really prefer 25mpg which would be about 17p per mile or a saving of £372 per year (so I can spend that much making the change and be no worse off. My bluebird turbo (same engine,heavier car, intercooled, more restrictive exhaust) was <14.5p per mile or 29mpg so it should be achievable.


that is a narrow band gauge running from a narrow band sensor (what are you using? the s12 doesn't have one as standard) they tell you nothing at all.

sounds like you have a boost leak to me

Wocketfast 11-03-2007 12:20

Quote:

Originally Posted by sideways danny (Post 15800)
that is a narrow band gauge running from a narrow band sensor (what are you using? the s12 doesn't have one as standard) they tell you nothing at all.

sounds like you have a boost leak to me

It came on the car (Northerners old s12) so I have no idea what brand it is, but yup it doesnt tell you much.

I too suspect a boost leak and Im pointing the finger at the dump valve which I want to ditch.

alundra 11-03-2007 14:17

Ok, I have a S12 with 8 sparks plugs system and emission control AND a stock 02 sensor came with this car.

I have take the signal that come in ECU for my A/F gauge.

At idle 14.40, 14.50, 14.60 with or without headlights electronics etc...

I know the difference between narrow and wide band sensor but for me it's sufficent for ECU, the motor and the monitoring of it.

I'd like to go at 0.8 bar or 1 bar but i prefer go safe because i need to know how make a detonation "gauge", i'm really scary about detonation in a car.

For 10.00 ratio is too rich and rich is'nt good for pistons too, right?

I'd like to remap but I have mk1 ECU as I said.... If you have any info on a mk1 remap I'll take it ;)


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