What AFC Live full travel spring?

cliff-1972

cliff-1972

New member
I have the early AFC Live Stage 2 and been using it for over a year now.I installed it with the 21 psi full travel spring because that's what kinda spring tension is what I ran with out AFC Live.I was running a light spring set at 65 psi full travel w/a "100" plate full forward.Well,with the AFC Live and light,21 psi,spring there is no difference acceleration in either position of the switch.Looking at the other springs included I noticed a compound turbo spring.Is this the one,I'm guessing yes,I should been running.The truck has less power now than before AFC Live.
 
If it feels like it has less power now, more than likely you would need a lighter spring, assuming it's not overfueling and the cause of the power loss. I'm not sure what their compound turbo spring is, but I bet it's an even stiffer spring because of the higher boost pressure of compounds.
 
Yes it is a stiffer spring.My issue is a lull/hesitation/bog when you go to full throttle fast.Example,going 70 mph (15-17 psi boost/2000 rpm) it's as though power is not right there.However,you can give throttle less aggressively and it takes it better with less of what I mentioned above.
 
Skip the compound turbo spring it is very stiff, I wish I would have grabbed the one step below when I got mine. I went back to a TST spring for now


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A super stiff spring wont work great for a single. You will go from off boost fuel to a few mm of rack pretty well but from initial movement to full travel will be lathargic. With compounds boost climbs very quick when the primary gets moving making a stiff spring desirable.

A spring that initialy moves at 2-3psi, half travel around 20 and maxes around 35-40psi works very well for a street driven single.
 
turbo2387 said:
A super stiff spring wont work great for a single. You will go from off boost fuel to a few mm of rack pretty well but from initial movement to full travel will be lathargic. With compounds boost climbs very quick when the primary gets moving making a stiff spring desirable.

A spring that initialy moves at 2-3psi, half travel around 20 and maxes around 35-40psi works very well for a street driven single.
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So,in your opinion do think the stiffer spring would suit me better than the full travel at 21 psi spring?Thanks for the input.
 
Depends On how much boost your running. If you are over fueled and streeting it a stiffer spring works better. But too stiff slows or limits the total foot movement which will make your driving experience different. A stock spring which is completely collapsed at around 22psi works but in a modified truck the fuel curve is so fast an actual tune doesnt really exist. Spring stiffnes depends on appication and total boost. My spring doesnt start to move until 12psi. Which gives me a noticanle lag when hot rodding BUT! Is a blessing while towing. Helps everything in that regard. Hurts 1/4 times. Everything depends on application.
 
How tight is your star wheel with the spring rated at 21psi? If you have too much preload on it, the rack won’t move quick enough when on the throttle... is the switch isn’t making a difference, i would guess you already have your regulator and restrictor valves all the way open, acting like the afc live isn’t even here.
 
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Also keep in mind that even with AFC live you still need to set your preboost according to your driving style and acceptable smoke output.
 
For my daily driver, I like our 30 to 35 psi boost spring. We rated the pressure based on overall boost the engine makes to help new comers figure out which spring to get. The 30-35 psi spring goes full travel at 26psi boost when the starwheel is set to full loose. It's a little too aggressive for something with 5x018" full cut DV's, etc., but you can slow it down with the AFC LIVE. I like it because it's as aggressive as I would ever want it, yet still gives some tuning range from 0 to 26psi is the range from min to max power.

If I didn't have AFC LIVE, I would run a heavier spring that better controls the fueling. I used to run an old governor spring and it would take 55 to 60 psi to go full travel with the star wheel set to full loose. The problem with the old spring was sometimes when towing, I'd run up against the AFC foot around 25 psi boost and couldn't give it more fuel to build boost to advance the AFC further in the 1800 to 2200 rpm towing range. I either had to live with that maximum throttle setting or downshift. On a WOT hit on the street, RPM was much higher and the old governor spring worked well to correctly bring the fuel in as boost came in from the compounds and never had an issue with the 25 psi throttle advance/afc stop.
 
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Big Blue24 said:
For my daily driver, I like our 30 to 35 psi boost spring. We rated the pressure based on overall boost the engine makes to help new comers figure out which spring to get. The 30-35 psi spring goes full travel at 26psi boost when the starwheel is set to full loose. It's a little too aggressive for something with 5x018" full cut DV's, etc., but you can slow it down with the AFC LIVE. I like it because it's as aggressive as I would ever want it, yet still gives some tuning range from 0 to 26psi is the range from min to max power.

If I didn't have AFC LIVE, I would run a heavier spring that better controls the fueling. I used to run an old governor spring and it would take 55 to 60 psi to go full travel with the star wheel set to full loose. The problem with the old spring was sometimes when towing, I'd run up against the AFC foot around 25 psi boost and couldn't give it more fuel to build boost to advance the AFC further in the 1800 to 2200 rpm towing range. I either had to live with that maximum throttle setting or downshift. On a WOT hit on the street, RPM was much higher and the old governor spring worked well to correctly bring the fuel in as boost came in from the compounds and never had an issue with the 25 psi throttle advance/afc stop.
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Will,I talked with Lonnon and suggested the compound spring from your kit.I have the (large) red knob turned 2 1/2 turns in from loss and the (small) black knob turned all the way out right now till I get the red knob adjusted where I want it.After that is set I'll fine tune the black knob to how quick I want the foot to move.You agree with me using that (compound spring) or swap to the 30-35 psi spring?Thanks for all y'alls help.Also,I'm going to swap out my 1.32 housing to a 1.15 housing on my primary in the near future.
 
My opinion is different than most of the other guys that work at PDD. To my defense, I daily drive a compound setup with AFC LIVE so I'm certain I have more real-world mileage and time playing with it than any other person here. Lonnon has more time on the phone dealing with customers and their questions so maybe it's easier to help customers get an acceptable tune-up with the heavier compound spring on trucks equipped with compounds. Lonnon does own a 12v 4x4 with compounds and he drives it once a week or so, and the compound turbo spring works great 90% of the time. I just find when I detune for extremely heavy loads, there are times when the compound spring is too stiff. With the faster spooling K27/369 setup, the compound spring rarely hits points where it's too stiff or I can feel that stiff pedal feel when the governor arm is up against the slowly advancing AFC foot. When I was running the 363/S480 setup detuned for towing heavy w/EGT control, the compound spring was noticeably too stiff around that 25psi total boost range and caused those weird instances where I couldn't accelerate without a downshift.

I'm at high altitude, when towing down in Texas, it's so much easier to make boost and run clean, and have power on demand, it's much easier to tune and I could probably use the compound spring just fine and never get the sensation that the compound spring is too stiff.

I will say this, it's easier to do a rolling 40 mph burnout with the 35 psi spring and AFC LIVE flipped to kill mode, than with the compound turbo spring. That split second fueling delay from the compound spring brings the power in just a tad later, a tad cleaner, but less tire shredding instant torque and therefore harder to do a rolling "power burnout".
 
Big Blue24 said:
My opinion is different than most of the other guys that work at PDD. To my defense, I daily drive a compound setup with AFC LIVE so I'm certain I have more real-world mileage and time playing with it than any other person here. Lonnon has more time on the phone dealing with customers and their questions so maybe it's easier to help customers get an acceptable tune-up with the heavier compound spring on trucks equipped with compounds. Lonnon does own a 12v 4x4 with compounds and he drives it once a week or so, and the compound turbo spring works great 90% of the time. I just find when I detune for extremely heavy loads, there are times when the compound spring is too stiff. With the faster spooling K27/369 setup, the compound spring rarely hits points where it's too stiff or I can feel that stiff pedal feel when the governor arm is up against the slowly advancing AFC foot. When I was running the 363/S480 setup detuned for towing heavy w/EGT control, the compound spring was noticeably too stiff around that 25psi total boost range and caused those weird instances where I couldn't accelerate without a downshift.

I'm at high altitude, when towing down in Texas, it's so much easier to make boost and run clean, and have power on demand, it's much easier to tune and I could probably use the compound spring just fine and never get the sensation that the compound spring is too stiff.

I will say this, it's easier to do a rolling 40 mph burnout with the 35 psi spring and AFC LIVE flipped to kill mode, than with the compound turbo spring. That split second fueling delay from the compound spring brings the power in just a tad later, a tad cleaner, but less tire shredding instant torque and therefore harder to do a rolling "power burnout".
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same here in quebec.. im not in high altitude.. but the heavier spring from PDD was too stiff.. swaped to the 35-45 and i gainned spoolup.. the fuel come faster but no more smoke than with the 45-60.. maybe a weaker spring would do beter again.. but not tested yet!
 
Big Blue24 said:
My opinion is different than most of the other guys that work at PDD. To my defense, I daily drive a compound setup with AFC LIVE so I'm certain I have more real-world mileage and time playing with it than any other person here. Lonnon has more time on the phone dealing with customers and their questions so maybe it's easier to help customers get an acceptable tune-up with the heavier compound spring on trucks equipped with compounds. Lonnon does own a 12v 4x4 with compounds and he drives it once a week or so, and the compound turbo spring works great 90% of the time. I just find when I detune for extremely heavy loads, there are times when the compound spring is too stiff. With the faster spooling K27/369 setup, the compound spring rarely hits points where it's too stiff or I can feel that stiff pedal feel when the governor arm is up against the slowly advancing AFC foot. When I was running the 363/S480 setup detuned for towing heavy w/EGT control, the compound spring was noticeably too stiff around that 25psi total boost range and caused those weird instances where I couldn't accelerate without a downshift.

I'm at high altitude, when towing down in Texas, it's so much easier to make boost and run clean, and have power on demand, it's much easier to tune and I could probably use the compound spring just fine and never get the sensation that the compound spring is too stiff.

I will say this, it's easier to do a rolling 40 mph burnout with the 35 psi spring and AFC LIVE flipped to kill mode, than with the compound turbo spring. That split second fueling delay from the compound spring brings the power in just a tad later, a tad cleaner, but less tire shredding instant torque and therefore harder to do a rolling "power burnout".
Click to expand...

Will,all have been running was the 21 psi.I believe this was fueling way to quick probably.It runs pretty good so far with the compound spring and I am at sea level too.I understand what you are saying about the 30-35 psi and may try that in the near future.As I stated in the above post,I will be going to a 1.15 96mm turbine housing.I your opinion,would you think due to quicker spooling the 30-35 psi is the better option?Thanks
 
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