Injector size - what's the solution?

[DestinWahoo]

I contacted Aeromotive and Anderson Ford Motorsports for Injector size.
I got two very different answers. Aero says 50lb injectors, where as, AFM says 38lb injectors will work fine.
My calculations show the 38lb in range, but I want to get right the first time and not rebuy.
The engine arrives next week and I need to get my tail in gear.

Here is the specs on my engine for reference;

LONGBLOCK: 347 SB2002 PRO BULLET FT/TW:
347 cid short block Balanced to racing tolerances and blueprinted.

RODS: 4340 forged steel ultra-lite 5.400" I-beams w/ ARP bolts & full floating pins

CRANK: nodular iron 3.40" stroke,

PISTONS: forged Pro-X # 4320 (FT/TW -3cc),

RINGS: moly E-458K,

ROD BEARINGS: tri-metal CB-634P,

MAIN BEARINGS: tri-metal BC240J,

CAM BEARINGS: tri-metal CC440

MAIN SUPPORT SYSTEM: 6061-T6 X 3/4" ALUMINUM

CYLINDER HEADS: Trick Flow Twisted Wedge 185CNC ported heads, 2.02/1.60 valves, #51400004-C01

INTAKE: Trick Flow Track Heat (TFS-51511002)

ADAPTER: Trick Flow (TFS-5150SN95-11)

PHENOLIC SPACER: 1†(TFS-51520008)

TIMING CHAIN: Pro Gear 3 Position

430HDSTK LIFTERS: Ford Racing

RETAINING HARDWARE: Hydraulic

PUSHRODS: 4130 .080" Wall Seamless

HEAD BOLTS: ARP 8740 Hex Head Bolts

HEAD GASKETS: Fel Pro Graphite 8548 PT2

ROCKER ARMS: DSS Aluminum Roller Rockers

T-WASHERS: 1/2" to 7/16" reducer bushings for cylinder heads

CAMSHAFT: Comp Cams XE274HR Roller (.555"/.565" 224°/232°@.050"
112°LSA 2200-6200RPM) (35-518-8)

BALANCER: 28oz SFI Steel/Aluminum balancer 1 (208SA)

FLYWHEEL: Fidanza SBF 157T/late model SFI aluminum flywheel
(28oz balance,replaceable friction surface) (186501)

WINDAGE TRAY: 5.0 Stroker Pro Tray 1 (7005)

ARP flywheel bolts: 7/16" x 1.00" 6pcs (manual trans) (100-2801)

ARP balancer bolts: 289-460 except 351C (150-2501)

OIL PAN: OP7050 DSS low profile 7qt oil pan with pickup and
passenger side 3/8" NPT baffled oil return hole (for supercharger/turbo).

OIL PUMP: OP1000 DSS 302 std volume oil pump kit Includes pump
w/ adjustable pressure, heavy duty oil pump and pickup
fasteners, and an ARP heavy duty oil pump driveshaft.

DISTRIBUTOR: MSD #8455

THROTTLE BODY: PP 75mm (69212)


http://www.fishingdestinflorida.com/cobra/MyFavoriteToy/index.html

 

[Adam]

38lb injectors will support 675 crank hp. If this is an NA motor, (looks to be) 38's shold be plenty.

 

[DestinWahoo]

Yes it's NA. Thanks for the help! DSS thinks it will be around 450 FWHP.
I am using electric water pump and anything else I can think to squeeze out extra HP.

 

[94twinscrew]

50's?! that's way overkill for the new NA combo.lol 38's would leave you PLEANTY of room to grow in NA form. Hell,for that matter,it could be done with 36's.

 

[IceMan]

if you are staying N/A 36-38 lb should be fine... even 42's might be an overkill...

 

[Adam]

Good injector calculation is:

(number of injectors X size of injectors=total lbs of fuel per hour)
____________________________________________________
divided by BSFC(.45 on NA or .60 on Blower cars)


8 X 38lb= 304lbs of fuel per hour/ .45 =675hp at 100% duty cycle.
You can figure out any injector with this calculation

 

[DestinWahoo]

Thanks Adam, I was looking to run at an 80% duty cycle to prevent abusing my injectors.
But, I find everybody has a different opinion as to the right size.

 

[DestinWahoo]

Decided to go with the 38 pounders, but now It occured to me that I need to ignite the fuel.
Looking for suggestions on the best plugs for this build.
I will post pictures of the tear down and rebuild as soon as I can.

 

[Adam]

Decided to go with the 38 pounders, but now It occured to me that I need to ignite the fuel.
Looking for suggestions on the best plugs for this build.
I will post pictures of the tear down and rebuild as soon as I can.

Thats a good plan. Even at 80%, thats still 540hp, I think you will be fine.

 

[ripper]

Crap with that motor i see a blower in the near future. Get 42's. Plug wires? Taylor Thundervolts 10.5.

 

[blown98gt]

http://sn95forums.com/index.php/topic,35563.0.html

 

[BigTang]

just curious but why that cam? its robbing at least 30 hp from you.

 

[Javi]

Back from dead.

 

[BigTang]

Back from dead.

crap, i didn't even notice that. At least it wasn't me that dug up the corpse.