Tuning With An Air/Fuel Gauge

[madkaw]

Well this is the point where you need to decide whether to continue with the OEM EFI or go programmable .

Yes the 123 ignition basically drops in with some wiring to adapt to factory wiring . It’s 600$ approx. You should watch a you tube video on it .

Same amount of money would get you a basic programmable  ECU like a Megasquirt . Then you would have full control of the engine with many options - ESPECIALLY if you want to modify your engine one day . 

[Patcon]

@chaseincats

Being in Texas I wouldn't think smog or inspections would be an issue?

[chaseincats]

1 hour ago, madkaw said:

Well this is the point where you need to decide whether to continue with the OEM EFI or go programmable .

Yes the 123 ignition basically drops in with some wiring to adapt to factory wiring . It’s 600$ approx. You should watch a you tube video on it .

Same amount of money would get you a basic programmable  ECU like a Megasquirt . Then you would have full control of the engine with many options - ESPECIALLY if you want to modify your engine one day . 

Well, the whole point of this thread was learning how to tune the stock system but thanks for letting me know.

[dutchzcarguy]

19 hours ago, chaseincats said:

Which heat rating though (bp5, bp6, bp7)?

If your engine is standard, use BPR6ES sparkplugs and let us see a picture of the plugs after an hours drive.

[chaseincats]

4 hours ago, dutchzcarguy said:

If your engine is standard, use BPR6ES sparkplugs and let us see a picture of the plugs after an hours drive.

Will do - curious why I shouldn't change to BPR5 or BPR7?

[jonbill]

3 hours ago, chaseincats said:

Will do - curious why I shouldn't change to BPR5 or BPR7?

Because cylinder temps aren't much changed by being somewhat leaner at idle.

[AK260]

This may help 

 

The R just means Resistor - used to reduce EM “noise”.

good read on heat range and the why

https://www.ngk.com/what-is-a-spark-plugs-heat-range-2

Edited January 22, 2024 by AK260

[Yarb]

Very cool!! Thanks for posting this chart. Answered a lot of questions?👍👍

[chaseincats]

So if I'm understanding this right.  When running leaner, it's better to use a BP5 plug since it will absorb cylinder heat better than a BP6?

[jonbill]

Its not about absorbing heat, its about keeping the tip of the spark plug at the right temperature to keep it clean but not burn. When the cylinder temperatures are higher (higher compression, different fuels etc) then the plug tip needs to be more shrouded to keep it a bit cooler.

I.e. a hot plug doesn't run hotter than a cold plug, they are all meant run at the same temp. A cold plug needs a hotter cylinder to keep it at the target temperature.

So if you were convinced that you change in AFRs was resulting in hotter cylinder temperatures, then you might fit a 7 plug. And then if you discover it gets fouled you could go back to a 6.

If you buy the cheap standard plugs, thats not painful.

[AK260]

Its not about absorbing heat, its about keeping the tip of the spark plug at the right temperature to keep it clean but not burn. When the cylinder temperatures are higher (higher compression, different fuels etc) then the plug tip needs to be more shrouded to keep it a bit cooler.
I.e. a hot plug doesn't run hotter than a cold plug, they are all meant run at the same temp. A cold plug needs a hotter cylinder to keep it at the target temperature.
So if you were convinced that you change in AFRs was resulting in hotter cylinder temperatures, then you might fit a 7 plug. And then if you discover it gets fouled you could go back to a 6.
If you buy the cheap standard plugs, thats not painful.

Wot he said!!!

Here’s the full explanation from the link I shared above

[chaseincats]

8 hours ago, jonbill said:

Its not about absorbing heat, its about keeping the tip of the spark plug at the right temperature to keep it clean but not burn. When the cylinder temperatures are higher (higher compression, different fuels etc) then the plug tip needs to be more shrouded to keep it a bit cooler.

I.e. a hot plug doesn't run hotter than a cold plug, they are all meant run at the same temp. A cold plug needs a hotter cylinder to keep it at the target temperature.

So if you were convinced that you change in AFRs was resulting in hotter cylinder temperatures, then you might fit a 7 plug. And then if you discover it gets fouled you could go back to a 6.

If you buy the cheap standard plugs, thats not painful.

The engine is absolutely running leaner which adds heat.  The TPS on a stock car basically keeps the car in WOT configuration at almost all pedal pressure we discovered earlier on in this thread, and since we bent that pin out a bit, the car will be in cruise mode longer (highway speed).  So maybe a 7 would be a good test in this case?