3406b model

im not sure but isnt that where the switch is for the jake?i dont remember its been a long time since i,ve seen a b model up close.

 

Yeah it's the jake switch. Idle speed is also adjusted from here.

 

Yea thats right the jake switch also is the way you adjust your low idle by screwing the switch in or out then snuging the lock nut.

 

i got a question on the 425 cat,i have a 15spd direct (no overdrive),when i'm running 60mph in the last gear (loaded) my exh. temp shoots up to 850*-900*. if i drop 1 gear the exh. temps go down to around 700*. my question is which exh. temp and gear is going to give me the best fuel mileage? oh yeah when i'm loaded in the last gear # 60mph,my tach is sitting on 14,but when i drop a gear it goes up to 16-17

 

The higher RPM's is move more air so thats why the temps drop. I'm gonna guess the fuel isn't turned up on this yet?

 

no it's still set at stock,but my question also is if turn the screws on the pump is it going to screw up my fuel mileage? it gets excellent mileage as it sits,so i don't want to screw that part up.

 

My fuel mileage got better when I turned it up. At first it will drop drasticly cause your not use to it, once you get it figured out it will come back up.

Mine on a hard pull only gets to 950* turbo temp, lugging it to about 1300rpm on a hot day. I've got a BW turbo its not the stock one so that helps some.

 

ok,i think my mechanic suggested that i keep the exh. temp below 900*. are you saying that it's ok to run the exh. temp above 900*? what combo is going to give me better fuel mileage? last gear running 60 # 1400 or 14th gear running 60 # 1600-1700 rpms?

 

might be the higher rpm's, you'll just have to try it and see.