Air/fuel Ratios

[turbotrana]

The air fuel ratio is just as important as timing advance at maximum boost.

Dynowog, how about giving us your experiences as to what advance you are using on the BA series engine.

Heck I'll start. My 512rwhp 202 turbo trana runs 12 to 12.5 A/F ratio and gives most power at 28 degrees timing advance. Max power at 23psi. This is what this engine likes. I cant get it to ping at even 32 degrees advance but this is more indicative of the engine not being too efficient.

Most other turbo engines I tune I end up sticking to around 20 degrees +/- 5 degrees depending on specs. Most well engineered setups wont ping even at boost levels around 20psi+.

I dont tune for power, I just tune for known safe/conservative values and use boost to get power. I find its no problem to get 500rwhp at 20 to 25psi for a well engineered set up.

Enlighten us Dynowog

Just for my own infomayshin, what are considered safe AFRs for these things?

I'm talking about a car that's going to be driven daily, and needs to be as reliable as a very reliable thing.

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well how long is a peice of string???

the tuning method needs consideration some of nizpro's earlier tune were 14.7 at full load eg miss ally's no ping and safe

my method is around 12.4-7

others use 10's and 11's

each to their own!!!!!

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[ms700]

My XC has been tuned for 11:5 to 1, I have always been told that blown cars need to run a tad fat. It blows a fair bit of black smoke, but that doesnt worry me!

[Romulus]

11.7-12.0:1 without a doubt. Anyone that tuned my car leaner (no one will anyway) will have to use a pyro to convince me the engine won't melt. Richer mixtures also reduce the onset of knock.

12.4-12.6 is good for an N/A engine imo.

3500 - 4000rpm sees around 10 degrees of spark, peak rpm around 12 degrees of spark. Less spark = more heat = more reason to add fuel to cool engine.

Mind you this is with stock intercooler and plumbing setup.

Edited 22/06/06 10:24 AM by M6 XR6T

[Romulus]

I think you'll find a lot of the Jap cars run extremely rich when tuned 10.5-11.0:1

[Xtreme F6]

11.7-12.0:1 without a doubt. Anyone that tuned my car leaner (no one will anyway) will have to use a pyro to convince me the engine won't melt. Richer mixtures also reduce the onset of knock.

12.4-12.6 is good for an N/A engine imo.

3500 - 4000rpm sees around 10 degrees of spark, peak rpm around 12 degrees of spark. Less spark = more heat = more reason to add fuel to cool engine.

Mind you this is with stock intercooler and plumbing setup.

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isnt this your dyno graph here here?

http://www.fordxr6turbo.com/forum/index.php?showtopic=26038

[stedz101]

11.7-12.0:1 without a doubt. Anyone that tuned my car leaner (no one will anyway) will have to use a pyro to convince me the engine won't melt. Richer mixtures also reduce the onset of knock.

12.4-12.6 is good for an N/A engine imo.

3500 - 4000rpm sees around 10 degrees of spark, peak rpm around 12 degrees of spark. Less spark = more heat = more reason to add fuel to cool engine.

Mind you this is with stock intercooler and plumbing setup.

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I totaly agree on afr's, However I run upto 17 -18 degrees timing at peak rpm, 1.9 load point. In saying that I also run 1 heat range colder plug to combat cylynder temps.

[Romulus]

isnt this your dyno graph here here? 

http://www.fordxr6turbo.com/forum/index.php?showtopic=26038

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That's the dyno graph of the car with the stock injectors. It was a test tune to determine fuel pressure with the stock injectors and bigger pump. I don't advocate tunes like that on customers' cars. Looks similar to XXXR6T's dyno sheet though.

I'll post the dyno graph with the bigger injectors and the new APC dump pipe back exhaust shortly

Edited 23/06/06 08:04 AM by M6 XR6T

[Romulus]

Link to AFR graph here:

http://www.fordxr6turbo.com/forum/index.ph...t=54&p=397948

[turbotrana]

Good to see a couple of people quoting their advance. 10 degrees seems so conservative to me. Does anyone know what the factory settings are.

11.7-12.0:1 without a doubt. Anyone that tuned my car leaner (no one will anyway) will have to use a pyro to convince me the engine won't melt. Richer mixtures also reduce the onset of knock.

12.4-12.6 is good for an N/A engine imo.

3500 - 4000rpm sees around 10 degrees of spark, peak rpm around 12 degrees of spark. Less spark = more heat = more reason to add fuel to cool engine.

Mind you this is with stock intercooler and plumbing setup.

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[Romulus]

Good to see a couple of people quoting their advance. 10 degrees seems so conservative to me. Does anyone know what the factory settings are.

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I'll use the BF F6 as an example. At 1.6 load (maximum load) with the stock maps, starting at 2500rpm:

rpm 2500 3000 3500 4000 4500 5000 6000

spark 10 11 14 11.25 11.01 11.02 13.5

This does not take into account any ect and act correction, but gives an example anyway.