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Pulley Drop Vs Higher Timing (Custom Tune)

TheAce144

TheAce144

New member
Hi there! I bought an Overkill pcm last summer and was wondering what would be my best option for my future modifications (SSAC Headers and 3.6" MPS pulley)...I have a 04 CompG GTP with the following support mods

NGK Iridium IX Spark Plugs/Wires, CAI, 180 T-Stat, Overkill PCM

After looking at some threads on the forums, many claimed that increasing the timing of the pcm to 20* degrees and keeping the stock 3.8" pulley would be a better option than swapping to a 3.6" pulley and would actually make the car faster...

1) Would it be a better choice?
2) How would it affect KR? Gas mileage?
3) If I decide to do it, should I ask for a re-flash at the original seller (Overkill) or go get a custom tune?

Thanks for your precious time and advice.

Just want to make sure before I blow something up :)
 




x2 on the headers, you won't go much further with the pulley without them. it's a really delicate balance, basically you want both. keep in mind boost pressure isn't really what you're looking for, you want air flow, and you want to ignite the charge at the right time, not necessarily earlier. i would say start with the pulley and find what your timing should be, then put a bigger pulley on and adjust timing, and find what combo nets you the most power. keep in mind timing advance has to increase as engine speeds go higher, and small amounts of knock at higher rpms are like high knock at idle. don't be afraid to back out of the throttle if you see it
 


the piston's moving faster at higher rpms, you have to spark it earlier the burn the mixture by TDC. advance at idle is like 4-6*, WOT is like 17-20*
 
my idle is 22*

my WOT is 16*

Cruise is normally 36-40* unless I see a hill, then it drops into the 20's, teens for passing.

Never lower than 16 and 16 is when its generating boost.
 


How exactly does the posi-trac rear end on a Plymouth work? It just does.




Load, cylinder temps, predetonation, fuel, mixture, cylinder pressure...
 
Bio248 said:
so i wasnt the only one watching joe dirt the other day then...
Click to expand...

nope i was too... lol

plus i know we all know this but for the new guy the reason timing is so high while cruising is to get better mpgs... not so much for "performance" persay...
 
ok, your BOTH right.

Timing increases with engine speed AND with decrease in load.

HOWEVER, our boost goes up with rpm as well introducing another factor.

I find my timing drops a couple degrees from 3000-6000rpms or it will knock.
 
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