What AFR to run when N/a?

[sage2k]

Ihave a trickflow top end setup and would like to know what air fuel ratio I should run on it?
Also what timing are you guys running on TF heads?

 

[Grn92LX]

12.8-13.0 across and 18* initial. You won't get the a/f exact just by using fuel pressure and a 'matched' injector/mass air combo.

 

[sage2k]

I have a tweecer RT and will be using a wideband

 

[Black95GTS]

Using a tweecer, I left the stock tables alone until I hit 2500 RPMs. Then my A/F went to 13.0 until 6000 RPM. I shifted at 5600 anyway as I was stock headed.

The tweecer allows you to maintain stock characteristics then really let it fly when you got WOT. In your shoes I would shoot for 13.0 and have 36 to 38 degrees timing in by 2500 RPM.

Adam

 

[Methodical]

Using a tweecer, I left the stock tables alone until I hit 2500 RPMs. Then my A/F went to 13.0 until 6000 RPM. I shifted at 5600 anyway as I was stock headed...

The two upper rows right?

The tweecer allows you to maintain stock characteristics then really let it fly when you got WOT. In your shoes I would shoot for 13.0 and have 36 to 38 degrees timing in by 2500 RPM.

That is really what makes the TwEECer shine being able to adjust only the area you want adjusted.

Adam

Oh by the way, I have mine at about 12.6:1 with 32* timing confirmed with WB and TwEECer. I plan to up the timing but my laptop got all kinds of worms and just shut my system down. So now I am waiting for my XP OS to come in so I can upgrade and wipe the system clean. Luckily, I saved my tunes, plus wrote them down. Hell, I haven't been able to run my N20 yet because my laptop is on a break. However, I plan to hit the track before the season is over though.

 

[Black95GTS]

Yes that is correct. For a solid foundation in the TwEECer, check out Grady's website:

http://www.geocities.com/final_5_0/

and www.eectuning.org

You have to remember that you'll never really be "done" with a twEECer tune... at least I wasn't. I was still fiddling with it a week before I sold my car. I just couldn't resist....

Adam

 

[Killercanary]

I made my best power with my old AFR165/FTI cam/Edelbrock intake/stock shortblock with my AF at 12.7:1. Also remember than in an NA car, more timing isn't always better. In a power adder car you will make the most power right before it detonates, in an NA car you can usually go past the best max timing value before you hit detonating. The only way to tell is to find a way of measuring the cars acceleration with different total timing values. This can be done with datalogging if you do it under like conditions in the same place, a dyno, or at the track.

 

[final5-0]

Good points by all

Each combo can a bit different
but
For a range with typical NA Street Car combos during WOT conditions

I'd say 12.5 to 1 through 13.0 to 1 for fuel
and
32 to 38 degrees for spark

You just have to play around with the values to see
what your particular combo likes

btw ... you can see fuel ratios vary from time to time
sooooo
Be careful when comparing different peeps results

Things which can skew the results are:
placement of wb ... tail pipe sniffer
if the car is running cats or not
if the wb is caled accurately
etc

Grady

 

[sage2k]

I have longtube headers, the WB will go right after the collector around the 3 oclock position I believe. No cats.
I guess I will play with 12.5 to 13 and datalog and see what happens