Target AFR

cdigerlando · #1 06-15-2006, 08:03 AM

Anyone have any suggestions for optimum target AFR for tuning a turbocharged SVX? I'm running water injection above atmospheric pressure, so I doubt I will need enormous amounts of fuel on boost for cooling, but I will have to richen. I've been looking at LAN's numbers but don't want to run 10:1 as a starting point. Any input would be appreciated. I will be looking at the entire fuel curve up top and down low.

Thanks

Chuck D.

Phast SVX · #2 06-15-2006, 08:07 AM

12.3-5:1 @ 8ish lbs would be nice. Im running 12:1across omst of the band and it is happy. Lan runs 12.5-13.0:1 AFR

phil

SVXRide · #3 06-15-2006, 08:34 AM

I'm with Phil...the EG33 really, really doesn't like running too rich. 12.5 to 13:1 seems to be the sweet spot.
-Bill

cdigerlando · #4 06-15-2006, 09:37 AM

Quote:

Originally Posted by Phast SVX

12.3-5:1 @ 8ish lbs would be nice. Im running 12:1across omst of the band and it is happy. Lan runs 12.5-13.0:1 AFR

phil

I thought I saw were LAN was running 10:1. Right now I'm set up to run 14.5:1 from Atmospheric to 13.5:1 up to 8 psi in increments of 0.5 units. Below atmospheric I'm planning to run the program default of 14.64. Which is basically below 100 bar atmospheric. The program also defaults to 15:1 and finally 16:1 at very low vacuum very high rev. Did LAN generate any AFR graphs that I might be able to look at?

Chiketkd · #5 06-15-2006, 09:38 AM

Quote:

Originally Posted by SVXRide

I'm with Phil...the EG33 really, really doesn't like running too rich. 12.5 to 13:1 seems to be the sweet spot.
-Bill

Bill,

I'd recommend that range for an n/a or even s/c SVX. Turbocharged motors like to run a bit richer and I'd recommend something in the 11.5-12.3:1 range.

Phil, I think LAN's Stage 3 set-up runs richer than 12.5:1 in the upper rpms. He's running a lot of timing advance with boost, and actually think it's somewhere in the 11/10:1 range.

SVXRide · #6 06-15-2006, 09:52 AM

Quote:

Originally Posted by Chiketkd

Bill,

I'd recommend that range for an n/a or even s/c SVX. Turbocharged motors like to run a bit richer and I'd recommend something in the 11.5-12.3:1 range.

Phil, I think LAN's Stage 3 set-up runs richer than 12.5:1 in the upper rpms. He's running a lot of timing advance with boost, and actually think it's somewhere in the 11/10:1 range.

Chike,
Looking at all of the SVX dyno curves to date, I believe the EG33 actually loses power when it sees AFR in the 11/10:1 range - regardless of whether it's na or s/c. Check out the curve from Tom J's old car when whoever tuned it with the APEX -- I don't believe it ever dropped below 12:1 even in the upper rpms and it cranked out almost 200 Hp at the wheels.
-Bill

Chiketkd · #7 06-15-2006, 10:56 AM

Quote:

Originally Posted by SVXRide

Chike,
Looking at all of the SVX dyno curves to date, I believe the EG33 actually loses power when it sees AFR in the 11/10:1 range - regardless of whether it's na or s/c. Check out the curve from Tom J's old car when whoever tuned it with the APEX -- I don't believe it ever dropped below 12:1 even in the upper rpms and it cranked out almost 200 Hp at the wheels.
-Bill

I'm in agreement. n/a and s/c EG33 definitely like to have an afr in the 12.5:1-13.0:1 range. A turbo motor should probably be 1 point richer.

cdigerlando · #8 06-15-2006, 11:03 AM

I think you are both right, in that the AFR is much higher than the LAN numbers of 10:1, but don't forget, LAN did this for his high boost curves of 12 psi. I don't think he ran this at lower boost.

I fully expect to have to play with these numbers. I'm just trying to see what successes are out their for different boost levels and different ratios. If someone is running as low as 13.5:1 for an NA SVX then I need to bump up my ratios at that point on the curve. For boost I would really like to see what LAN was doing. It might save me a lot of hunting legwork.

Thanks for the input guys.