Tuning Afrs

[Don Dada]

Well the aussies general rule is to tune rbs to a full load afr of 12 and then tweak ign timing to suit for max power where as the japs throw in a shit load of fuel eg 10.5-10.0(keeping in mind that their pump is 100+) and then throw in a shit load of timing on top of that..

I know there must be "tuners" out there who may have experimented with both methods whether it be professionals or diy-ers but......

Which method is actually better??? There must be pros and cons to each?!?

The way i see it is that the Japs method may be safer in that they dump a shit load of fuel as extra protection and then wind in extra timing to make power,the down side being a higher cost at the pump .....

I mean with their 100+ octane you would think that there is no reason to run that rich.

But does this equate to the aussies method of leaning it out some(12.0) and not throwing in as much ign timing???

I have always had the impression that changes in ign timing is what really makes torque/power and afr was secondary...so therefore running a little richer will always be better in that u can throw in more timing hence making more safe power....

I know its kind of ironic starting this discussion here with no japs to defend themselves but still would like to hear different opinions....

Would have love to see dyno sheets of one of those big shot Jap tuning shops against Aus finest on the same vehicle

[scotty nm35]

Took one afr of e70 out on the dyno and made 15-20kw more, that would be safer than adding 20kw of timing I would have thought, not to mention cheaper to run. Street tunes will always be a compromise I guess.

I also heard of some Japanese tuners predominantly using exhaust temp gauges. I noticed with the ethanol I am still under 600 degrees at the turbine exit so this method may not work, surely this wouldnt be smart as exhaust temps would change depending on ambient temperature and engine loads wouldnt they?

[Dobz]

Well the aussies general rule is to tune rbs to a full load afr of 12 and then tweak ign timing to suit for max power where as the japs throw in a shit load of fuel eg 10.5-10.0(keeping in mind that their pump is 100+) and then throw in a shit load of timing on top of that..

Where's the evidence to say that australian and japanese tuners always tune in this way? It doesn't seem like it's something you can generalise.

[Don Dada]

If u do some reading and watch some dyno sheets on here u can easily see a pattern and every single Mines/blitz/pfc tune i've seen out of Japlan supports this as well

[scotty nm35]

If u do some reading and watch some dyno sheets on here u can easily see a pattern and every single Mines/blitz/pfc tune i've seen out of Japlan supports this as well

I have noticed similar patterns, Impul seem to tune for 11:1 afr from what I have seen. My tuner aims for 12:1 at wot.

[R31Nismoid]

If u do some reading and watch some dyno sheets on here u can easily see a pattern and every single Mines/blitz/pfc tune i've seen out of Japlan supports this as well

Mines and Blitz "chip/flash" ECU's sadly do not count.

They are nothing more than a typical mass produced tune. They are not specific and run rich on purpose.

[paulr33]

agree, youll probably find the remapped ecu's probably just aim for the richest AFR possible as a safety protection to suit all uses

[KiwiRS4T]

Tuning rich at WOT is not really going to affect your everyday fuel consumption and if you're tracking an RB of any sort petrol is the least of your worries! Keeping the engine alive is the number 1 priority for most!

[Don Dada]

Mines and Blitz "chip/flash" ECU's sadly do not count.

They are nothing more than a typical mass produced tune. They are not specific and run rich on purpose.

Ahhhhh....That make sense but i've also seen a few pfc with full tunes ie including low load areas, with rich as high load mapping

[Guilt-Toy]

He has a point, most cars you see running in videos in Japan blow 10afr worth of smoke and they all seem to be traveling at a great amount of knots. (correct me if i am wrong with this please)

But what we do not know or see is how how many engine failures they have there. Engines can be purchased aplenty to be replaced when one lets go, why not tune it on the ragged edge and feed lots of timing into it if its not going to send you bankrupt if you blow a engine or 2 while you are chasing that quarter mile target ??

can just imagine going through Maccas Drive through there, would you like a rb25 with your order? lol

[Don Dada]

The Japs know what they are doing.....i mean they made the shit to start with.

There must be engine failures of course but check out how many skylines get shipped worldwide some stock some with all kinds of goodies and they are still mostly in good working order for us to trash

Have u ever experimented with one of these rich ass tunes Anthony?

Would be interesting to have an idea as to how much timing can be added with running say 10.5 as compared to 12.0

Dynos here suck....no afr readout on the graph

[Dale FZ1]

If they're running less than 11:1 I see it as a bandaid attempt to address exhaust temps. The fuel is acting as a cooling medium - for anyone who watched the F1 cars of the turbo era, on qualifying trim they would blow plumes of black smoke, bit like when you watch a jet plane on takeoff. Same approach just to try and avoid a mechanical failure.

But you're then putting so much fuel into the cylinder that it HAS to be super advanced just to try and burn the fuel load.

I've seen a car on the dyno just ramping up to full load with 10.5:1 AFR and the engine was just hesitating like all get-out. With conventional ignition map the poor thing just wouldn't run right.

The other issue would be a tendency to wash down the bores and promote rapid/excessive wear. If they have money to burn for pull-downs and its all about that last tenth on the track I can understand but not otherwise.

[DVS JEZ]

If they're running less than 11:1 I see it as a bandaid attempt to address exhaust temps. The fuel is acting as a cooling medium - for anyone who watched the F1 cars of the turbo era, on qualifying trim they would blow plumes of black smoke, bit like when you watch a jet plane on takeoff. Same approach just to try and avoid a mechanical failure.

But you're then putting so much fuel into the cylinder that it HAS to be super advanced just to try and burn the fuel load.

I've seen a car on the dyno just ramping up to full load with 10.5:1 AFR and the engine was just hesitating like all get-out. With conventional ignition map the poor thing just wouldn't run right.

The other issue would be a tendency to wash down the bores and promote rapid/excessive wear. If they have money to burn for pull-downs and its all about that last tenth on the track I can understand but not otherwise.

Agreed. Its just a waste of fuel. Heaps of fuel and heaps of ignition or less fuel and less ignition to give a similar result.

Maybe the japs run absolutely stupid amounts of boost and they just dump heaps of fuel to suit.

[SS8_Gohan]

the "flashed ecu's" aren't always just off the shelf tunes - some of the big workshops will use the standard ECU just like a remap.

Not sure the reason why some of the top workshops do this, maybe they feel that with their builds and their tunes, they don't usually have problems and so won't let people fiddle. Or they just want to lock their customers in to their workshop.

i wonder if they all have different software packages or what they use to turn the standard ECU into something that can be flashed.

maybe all just nistune remaps

[PROXIMITY]

years ago everyone wanted to add more fuel to their engine, know it seems we want to run them leaner.

I have read many articles were japs tune by exhaust temp only an not afrs, im sure they have their reasons for doing this thou.

would be good to see someone dyno same car at rich setting with lots ignition then the way we tend to do it and see ramp/power differences !

[D_Stirls]

As others have said, i don't think that you can conclude anything for what is essentially a "mail order" tune. Due to the fact they aren't a tune specific to any engine they can't be as "on the edge" as other tunes that are done on the car that will be running the tune.

Personally i think that MBT tuning will be the way of the future in terms of timing as the results are better and generally they are safer as "less/ideal" timing is used. The only down side is the cost at the moment due to the dyno time needed.

[DVS JEZ]

years ago everyone wanted to add more fuel to their engine, know it seems we want to run them leaner.

I have read many articles were japs tune by exhaust temp only an not afrs, im sure they have their reasons for doing this thou.

would be good to see someone dyno same car at rich setting with lots ignition then the way we tend to do it and see ramp/power differences !

exhaust temps are mainly used between individual cylinders to make sure that one or more cylinders arent running leaner than the others.

a leaner cylinder will run hotter and if a hotter cylinder is found that cylinder can be richened up to match the rest.

[Guilt-Toy]

I have run cars up on the dyno that have showed 10.5 afr's during tuning and have not had misfire or any problems with the run. You can run them that rich.

As for feeding timing into a engine that is running mid 10 afr's I have not done this yet. Never needed to. On my own car I run 11.1 afr atm and seems to be making healthy power with moderate ignition timing, its not advanced i just like to run my engine that way for insurance.

as a rule for customers cars i never go over 12 unless its a stockish car running low boost, then it will see 12.2 12.3.......

also if they are using really rich mixtures for a band aid for exhaust temp, who says the timing is too advanced? remember retarded ignition advance causes higher exhaust temp compared to a advanced tune.

Maybe they are chucking in a stupid amount of boost and running the timing very retarted and using the fuel to cool it down?

I would like to see some power fc maps of highly tuned cars to look into this further....

What the japs are really doing? we do not know... I would love to go there personally to check it out.

[SS8_Gohan]

As others have said, i don't think that you can conclude anything for what is essentially a "mail order" tune. Due to the fact they aren't a tune specific to any engine

some of the big workshops will use the standard ECU as THE tuning ECU. They will tune it to the specific build/engine. Yes people like Mines etc have ones you can buy off the shelf, but they will also use the standard ECU (modified somehow) for their builds as well. So if you got a workshop built car with a workshop flashed ECU, that wouldn't be an off the shelf item. It would have fully customised maps just like any aftermarket one would have.

which isn't the silly given the context, as the standard ECU obviously does things well like cold start, idle etc. I believe the newer Evo owners tend to keep the stock ECU and get it flashed. There are benefits sometimes to keeping factory items, albeit tweaked a little

[KiwiRS4T]

some of the big workshops will use the standard ECU as THE tuning ECU. They will tune it to the specific build/engine. Yes people like Mines etc have ones you can buy off the shelf, but they will also use the standard ECU (modified somehow) for their builds as well. So if you got a workshop built car with a workshop flashed ECU, that wouldn't be an off the shelf item. It would have fully customised maps just like any aftermarket one would have.

which isn't the silly given the context, as the standard ECU obviously does things well like cold start, idle etc. I believe the newer Evo owners tend to keep the stock ECU and get it flashed. There are benefits sometimes to keeping factory items, albeit tweaked a little

Yes they work fine for the Japanese tuning shops but they are not a good buy second hand if you don't have any way of altering the tune.