20 psi and a/f ?

[Blue shadow]

I have the 147.5 main jetting in and at 20 psi at 200 ft out I had to let go at wot ,the a/f was at 14.4 A/F ,I need to get it down to 11.8 so what jetting should I put in ,thanks

 

[rxrider]

Are you starving for fuel?

 

[snowy1]

I would go atleast 2 sizes and see where you at, you can turn up fuel pressure as well to fine tune.

 

[micke_o86]

I use 150 mains at 15 PSI with lambda 0.8

 

[rxrider]

Lambda 0.8 = AFR 11.76

 

[Ted Jannetty]

I have the 147.5 main jetting in and at 20 psi at 200 ft out I had to let go at wot ,the a/f was at 14.4 A/F ,I need to get it down to 11.8 so what jetting should I put in ,thanks

This does not sound like a jetting issue, sounds more like a fuel pump, pressure regulator, or volume issue.

This could be what took out your last motor.

 

[Skydog]

I have the 147.5 main jetting in and at 20 psi at 200 ft out I had to let go at wot ,the a/f was at 14.4 A/F ,I need to get it down to 11.8 so what jetting should I put in ,thanks

This does not sound like a jetting issue, sounds more like a fuel pump, pressure regulator, or volume issue.

This could be what took out your last motor.

Ted i think you are on to some thing.....

 

[Blue shadow]

Going out in the morning I will put a fuel pressure gauge on and see what it reads at 18 psi ,thanks The intercooler is getting more flow now with the little mod done to it .

 

[rxrider]

Fuel starvation is a BAD thing, but you already know that Hope you find the culprit.

I'm going out test riding the old girl this weekend, I'll pay special attention to AFRs and boost to prevent a lean- and or an overboost condition at WOT.

 

[Blue shadow]

Today on 660 ft with the 156.6 main jetting the A/F was 11.5 I was running 20 psi with a 6.25 seconds pass on 660 ft with a 1 1/2 ripsaw 136 inch track with no studs .It is hard to keep it from spinning for the first 300 ft .It takes me 300 ft to get the 800 xp and then I pass it like it was stop .Are you people using a lot of tranfer to get out faster on the start?I have all the tranfer off the rods when I did this .Would this be good or bad .she don t rise at all but leaves a big tranch behind

 

[Ted Jannetty]

Today on 660 ft with the 156.6 main jetting the A/F was 11.5 I was running 20 psi with a 6.25 seconds pass on 660 ft with a 1 1/2 ripsaw 136 inch track with no studs .It is hard to keep it from spinning for the first 300 ft .It takes me 300 ft to get the 800 xp and then I pass it like it was stop .Are you people using a lot of tranfer to get out faster on the start?I have all the tranfer off the rods when I did this .Would this be good or bad .she don t rise at all but leaves a big tranch behind

How is your fuel pressure?

 

[Blue shadow]

25 psi fuel presure on 20 psi boost is that ok?

 

[Ted Jannetty]

25 psi fuel presure on 20 psi boost is that ok?

Perfect , that is with 5 psi base pressure.

Pretty amazing how much jet that needs.

I would go down to 152.5 though your a little too rich.

 

[Blue shadow]

thanks I will try that

 

[Blue shadow]

the front axle twist in two parts today ,Does this happend a lot on high boost?Any thing down from a 2003 would it fit or are they different ?thanks