enkeivette
Well-known member
- Joined
- Mar 30, 2008
- Messages
- 990
I had a dyno test done recently, and my AF ratio was between 14 and 15:1 at WOT. I have an annular Mighty Demon 750 (centrifugal SC 383) 78s in the primary block with a PV, 88s in the secondary block.
I do not yet have an LM1, nor will I any time soon. So I called BG for a jet recommendation, the tech told me to go up 1 size on all 4 corners. Didn't sound right to me. So I did some research, found this article. They have a similar setup, made similar power, with similar AF ratio. With 67/73 jets they had a 14.5:1 AF ratio, they increased the jets to 69/82 and brought the ratio down to 12:1, making an additional 47hp.
Here are my questions:
How many jet sizes must you go up in order to drop the AF ratio a full point? (Looking for rough ballpark answers)
Secondly, I'm only getting 5 1/2 lbs of boost. ATI seems to think that I will get closer to 10lbs when I tighten the belt. Is there a general rule of thumb? So many jet sizes up for so many lbs of boost?
Finally, I have a difference of 10 jet sizes between the primaries and secondaries. In the tech article they ended up with a difference of 13 sizes between the primaries and secondaries. Is this ok to do? (Single plane) I'd like to keep the primaries kind of lean for cruising.
I do not yet have an LM1, nor will I any time soon. So I called BG for a jet recommendation, the tech told me to go up 1 size on all 4 corners. Didn't sound right to me. So I did some research, found this article. They have a similar setup, made similar power, with similar AF ratio. With 67/73 jets they had a 14.5:1 AF ratio, they increased the jets to 69/82 and brought the ratio down to 12:1, making an additional 47hp.
Here are my questions:
How many jet sizes must you go up in order to drop the AF ratio a full point? (Looking for rough ballpark answers)
Secondly, I'm only getting 5 1/2 lbs of boost. ATI seems to think that I will get closer to 10lbs when I tighten the belt. Is there a general rule of thumb? So many jet sizes up for so many lbs of boost?
Finally, I have a difference of 10 jet sizes between the primaries and secondaries. In the tech article they ended up with a difference of 13 sizes between the primaries and secondaries. Is this ok to do? (Single plane) I'd like to keep the primaries kind of lean for cruising.