My First Dyno Run

[mr go fast]

3" ATR Downpipe
2.5" ATR Dual Exhaust
ATR Cold Air
Thrasher chip
topped out at 13lbs of boost on 91 octane gas
Stock motor with 108k

 

[mr go fast]

holy crap. Can someone resize that for me?

 

[charlief1]

holy crap. Can someone resize that for me?

I cut it down to 50 percent. Hope that helps.

 

[mr go fast]

thanks

 

[it's just a six]

Nice,
very steady A/F ratio!

 

[bison]

Good number for the low boost.That is a very lean a/f for 93 or lower octane. As you increase boost id drop it down. You should be able to go to about 16.5-17 psi with 18 degrees advance at 10.5:1 and pick up a bunch of power.

 

[it's just a six]

Just curious, what do you think a good A/F ratio should be?

 

[mr go fast]

Just curious, what do you think a good A/F ratio should be?

Around 4250 there was a slight lean spike and gave me a little power. I was thinking of leaning it out more than current setting.

 

[it's just a six]

Around 4250 there was a slight lean spike and gave me a little power. I was thinking of leaning it out more than current setting.

That was my point,12-1 lean ???, not sure I agree with the previous post ;-)

 

[bison]

Dont be deceived by the dyno jet. If you had a lean spike on there it will be at least as lean as that on the street especially in 3rd when you hit it. Safe a/f for forced induction is 10.5-11.0:1. On the pass in my sig i was at 10.8:1 through the whole pass. I noticed when i dynoed my old car i picked up a bunch going from 10.2 to 11.0 but only gained a few hp going leaner to 11.3:1. Leaner made more power but not much more and it increased the risk of problems from lean out.

 

[ryan george]

Dont be deceived by the dyno jet. If you had a lean spike on there it will be at least as lean as that on the street especially in 3rd when you hit it. Safe a/f for forced induction is 10.5-11.0:1. On the pass in my sig i was at 10.8:1 through the whole pass. I noticed when i dynoed my old car i picked up a bunch going from 10.2 to 11.0 but only gained a few hp going leaner to 11.3:1. Leaner made more power but not much more and it increased the risk of problems from lean out.

Bison, I didn't see that he was running alky...shouldn't that be a different (higher) ratio without alky?

 

[bison]

Bison, I didn't see that he was running alky...shouldn't that be a different (higher) ratio without alky?

With dual m15's and a 4 Bar MAP my target is 10.5:1 on 93 octane with boost around 30psi. Engine is making roughly 680hp at 28-29psi. With Q16 i targeted a conservative 10.8:1 and went 133.4mph at 28.5psi. I would never target leaner than 11.0:1 on 93 or lower octane with alky. Pump gas is a crap shoot and its co-solvent %'s change like the wind. Better to stay a little richer when putting in fuel that didnt come from a sealed container. With straight C16 and no alky i would have targeted 11.3:1 and wouldnt be too nervous if it hit 11.5:1 for a couple seconds. So there is quite a bit of difference when running alky or no alky and pump gas vs leaded race fuel that came from a sealed container. With more alky you drop the target number and run it richer.

 

[JDSfastGN]

ive got to disagree, bottom 12s is fine for pump gas and low timing low boost, shooting for mid to high 10s on pure pump gas would be very very rich imo. When you get it up to 16-17 psi 11.8:1would be safe. I run 11.2:1 safely on 93, all cars are different but 10s on pure pump is rich and will kill power.

 

[bison]

ive got to disagree, bottom 12s is fine for pump gas and low timing low boost, shooting for mid to high 10s on pure pump gas would be very very rich imo. When you get it up to 16-17 psi 11.8:1would be safe. I run 11.2:1 safely on 93, all cars are different but 10s on pure pump is rich and will kill power.

With the amount of alky im shooting in there i need to run the a/f richer. For those low boost numbers im sure the numbers are fairly safe. My fuel map is very close to the numbers you stated and i run a lot of timing all over on top of it. With race fuel and alky timing is more than 28* till it hits 20 psi then it tapers down to about 22*. With 93 its about 5 degrees lower over the same ranges. Im at 10.5:1 on pump right now and im not killing the power too much. From my testing maximizing the alky flow and pulling injector dc always made more power than just using the alky as an anti detonant. You have to lower the a/f as you increase alky flow or the cylinders get hotter and hotter even if theres no detonation.

 

[ryan george]

Bison, the point I was making was not about your setup. This guy had asked about his setup and I didn't see where he had listed that he is running alcohol, thus my question as to the AF ratio for HIS combination.

 

[it's just a six]

12.1 is fine for his combo.

 

[mr go fast]

I found out just this last weekend (after my intercooler hose fell off) that all of my hose clamps were loose. I tighten them all up and the car seems to run much better. Next dyno will be a bit better I hope. Thanks for the tech guys.