Need some input

[Cyclone_90]

hey guys I am going to be getting ready to tune my motor and I need a little input. Aight heres my mod list

DSMlink
650s
Walbro fuel pump
19c turbo
header
bulldog intake manifold
60mm 5.0 mustang TB
MLS head gasket
No balance shafts (Fully blanaced)
forged 8:3 compression pistons
3in turbo back exhaust
2.25 IC pipes
FMIC 20x8x3
Stage 2 cluchmaster clutch

My question is what amount of boost could I run with 650s without going over 90% of there duty cycle?? What type of air/fuel ratio should I be looking for??? What should my base timing be set at to start off safe? Is it possible to break low 13s to high 12s with that setup with some 225s BFgoodrich G-force KDW-2s FWD?? Any suggestions would be great thanks alot

 

[pyrex]

Figure out you airflow without boost (cubic meters per minute)

displacement*rpm / 1000000 (conversion from cc to meter cubed) = airflow

-displacement per revolution (only 2 of your 4 cyclinders fill per revolution, all fill every thermo cycle which is 2 revolutions) 2 liter = 2000cc so 1000cc

-rpm (you should use your redline since you are finding out how much boost related to fuel)

ex 1000cc *8000 rpm/1000000 = 8 meters cubed/minute

Figure out you airflow with boost (cubic meters per minute

airflow without boost * pressure ratio * density ratio =airflow

ex 8 m3/min *2.5 (22psi) * .75 (300/400) = 15 m3/min

density ratio is air temp / air temp @ intake manifold in degrees kelvin, if you dont know your intake mani temp, which is harder to calculate, the lower the number towards the outside temp the the more overdesigned your fuel system will be (safer) I suggest 400 degrees k as a guess.

(atm temp in degrees k which is 273C plus degrees celcius ex 27 degreed out today therefore 300 degrees k)

pressure ratio is intake mani pressure absolute / atmosphere absolute. absolute is 14 psi plus gauge pressure [(boost pressure plus 14psi) / 14 psi]

then convert to cubic feet per minute (times 35.9 ) then convert to pounds per min (times 0.069)

ex 8 *35.9 * 0.069 = 37.2 lbs of air per minute

Almost there

air fuel ratio 13.3:1 which makes best power. run lower to be richer which is safer extra fuel cools the system (11:1). this is in lbs per minute of air to fuel therefore if you know the airflow in pounds to minute you can find the required fuel

airflow in cubic feet per minute / air:fuel ratio = required fuel at that boost at max rpm

convert from lb/min to kg/min (divided by 2.2 lb) and them kg to cc per minute (times 1000)

remember this much fuel should be flowed by 2 injectors (2 cyclinders per revolution, 4 per thermo cycle). and you said 90% dc.

ex 37.2/13.3/2.2*1000 = 1270 cc fuel

so 650cc times 2 times .9 = 1170cc per min assuming your fuel pressure can flow 650 cc per minute through your injector. it to best to measure the fuel availible so you actually know instead of calculating it.

if you fuel required is higher than fuel availible, lower the boost and try again.

Good luck, pm me if you need some help or have question. I have to go to thermo class now, by the way, i am in final year of mechanical engineering and love ic and cars