blackz93

iTrader: (2)

shooting for 620-650 rwhp this weekend and just wondering if they will do it.

ive read other places that they should be good for 800 flywheel so maybe it wont be a problem...


thanks...

MYTURBOT/A

Well i`ve heard the 42s are good for 600rwhp so the 50s should be good for atleast 700rwhp.

sr71bb

iTrader: (3)

Go to http://www.smokemup.com and register. They have MANY utilities that calculate all sorts nifty things like INJECTOR sizing. So since you are using forced induction use .55 fir brake specific fuel consumption and you will get the following numbers which are CRANK HP:

Injector....Duty Cycle on Injector.....Crank HP.......RWHP (my estimate)
50 Pound........80%.........................580...... .......480-500
50 Pound........90%.........................650...... .......550-570
50 Pound.......100%........................725....... ......625-645

I wouldn't run the injectors any more than 90% of their duty cycle. Forced injection requires a LARGER injector than NA with the same HP requirements. They are some that beleive this chart is conservative but I would go with it myself. 50 pound injectors are the largest HIGH IMPEDANCE injector you can use with the STOCK computer WITHOUT having to use a software driver that will allow you to use the LOW IMPEDANCE injectors. ONCE you start using low impedance injectors however, a FAST system probably is not too far behind!!!

BTW this link is also VERY useful as well:

http://www.robietherobot.com/storm/f...ectorguide.htm

Slowhawk

iTrader: (12)

Matters how much boost it's fighting and what the fuel pressure is.I've seen them push 680hp with fuel pressure rising to 70psi.

y2khawk

iTrader: (5)

just FYI, those calculations are assuming...

1. Your fuel pressure is the same at which the injector is rated
2. Your maintaining a constant pressure across the injector (ie using a rise rate regulator)

unless you've got something more than a single intank 340 in the car, you'll be out of pump before you're out of injector. Even with the 42's in there. Been there, done that

smokinHawk

iTrader: (48)

largest high impedance injector out there is the 60lb not the 50lb

blackz93

iTrader: (2)

even with a boost-a-pump?

MYTURBOT/A

You`ll need twin walbros for your setup IMO.

sr71bb

iTrader: (3)

I now see that Siemens has a 57 pound high impedance injector, who makes the 60 pounders?????

red ws6 99

Based on all my logs (which jive with the calculators) at 80% and a base pressure is 58 psig (and a rising rate regulator) I will be able to get about 570 fwhp (with msd 50, pump is less). A single walbro 340gs stating at 58 psig and pressure going one-to-one with boost will run out about 550 fwhp (probably a little less). If your base pressure is 43 psig then the 340 is going to be worth quite a bit more. Hot wiring or boost a pump gets you little more.

Gary

y2khawk

iTrader: (5)

yep

I was running a volt-blaster with the alternator putting out close to 17 volts. Enough to cook the bearings outta the alternator

scottywheels

just throw a weldon 2025 like me and pro stock

Crunch

I'm running a single Walbro 340 AND a Vortech T-Rex with 50# injectors.
This combo seems to be working very well for ~530RWHP.

If I spray any nitrous, I'll have to upgrade the fuel rails and fuel lines.

BIGBOS

Mototron makes the 60#, they are not flow matched though, this is why I'm considering the 57's as well.......

Pro Stock John

iTrader: (34)

Remember most injectors are rated at 43psi, and LS1's run 58-60 psi base fuel pressure.

ChrisB

You can't accurately determine that without knowing what your BSFC is. You can estimate, but every setup will be different.

Also, if you are looking at the MSD 50's, I wouldn't use them - I have tuned them before and do not like them. The siemens 57's would be my choice for big high-z injectors (though I would get a box from LJ/Speed Inc. and run low-z ).

As for pump, I wouldn't mess with aeromotive, weldon, etc (though weldon are definitely top notch - the best you can get, I think they are overkill and even a bit dubious on a street car unless you get the DC controller also to go with them (a must on the street)). Just do 2 intank/inline GSS340's or equivalent. Will support more flow than any of those injectors will, and you get stock reliability and sound level. Plus it's cheaper (especially than weldon).

Pro Stock John

iTrader: (34)

Aren't dual intanks like $700? That's Weldon territory.

I also like the idea of running dual external pumps.

QuickSilver2002

Humm, I've seen/read about several C5s running a single racetronix intank with a BAP and hitting 650+RWHP without running out of pump. The LPE 427TT also uses a single intank with a BAP. Maybe the c5 fuel sender is the difference.

I agree about the intak comments. The externals are just too loud and unreliable for a street car.

Evil F1 SS

I have a set of 50# injectors for sale, flowed and never used. 300 Shipped.

Gordon
ruckuss303@aol.com

MIGHTYMOUSE

iTrader: (59)

i paid a hundred bux each for my dual walbros in tank. maybe 6 bux worth of rubber hose, 5 bux for band clamps, 7 bux for a relay and 'found' wire at work

grand total is an easy 510lph for < $250.. and nice and quiet too.

fwiw i have the somewhat questionable mototrons in my car now and i'm going to run them 'out' on the new set up before switching to the 83's.

also consider:
https://ls1tech.com/forums/fueling-injection/128238-fuel-flow-line-size-pump-calculator.html
and
https://ls1tech.com/forums/fueling-injection/128515-low-impedance-converter-box-72-injectors.html