MSefi.com read only forum (Jan.15,2018)

I'm running the Holley Commander 900cfm TBI with 4 85pph injectors and my Injector Characteristics are set as follows:

Open Time 0.8ms
Battery Correction 0.20 ms/v
PWM Current Limit 30%
PWN Time Threshold 0.8ms
PWM Period 66us

REQ Fuel = 7.1 ( 408ci )
Control Alogorithm = Speed Density
Injections Per Engine Cycle = 4
Injector Staging = Alternating
Engine Stroke = Four Stroke
Number of cyls = 8
Injector Port Type = Throttle Body
Injectors = 4
Engine Type = Even Fire

I have the secondaries linked to the primaries to open 1:1. What can I do to get the finest mist from the injectors? My fuel pump maxes at *14psi, so maybe upgrade to something 20psi to apply more pressure to the injector which would create a finer mist?

Thanks!

Raising the fuel pressure is probably a good idea. What pump are you currently using?

Not much else that I can think of.. I'm using a very similar setup to you except on a 351W.

BottleFed70 wrote:Raising the fuel pressure is probably a good idea. What pump are you currently using?

Not much else that I can think of.. I'm using a very similar setup to you except on a 351W.

It's a summit 14PSI ( I thought it was 16 all this time ) 140gph cheapie.

http://store.summitracing.com/partdetai ... toview=sku

Guess I should get this one:

http://store.summitracing.com/partdetai ... toview=sku

The injectors say 85pph at 21PSI... but I'm at 4800' elevation and am not getting the 500+ FWHP I do at lower elevations. Car dynoed at 402 SAE corrected RWHP down in Kansas City, KS two years ago on a 750 carbie that was running fat ( 11.5:1 AFR ). With a few changes since then, I'm guessing it's running around 450 SAE corrected RWHP ( 525+ FWHP ) on the dyno, and probably 400-425 FWHP at my altitude.

definite get a new pump. The pump you have is ment for carbs and probably doesnt give a nice constant pressure like an EFI pump.

Dont buy that other pump tho either...

I would reccomend a warlbro 255lph external pump. Do an ebay search for WALBRO GSL392

You will find something like this.
Edit: eBay links not allowed on the forums. ~Forum Admin Team
These pumps are high quality, work great (I use one) and wont break the bank either.

Will rubber hose work with that pump or is it too much pressure? I have about 6" of rubber hose going into the TBI and 6" from the pump to the aluminum fuel line.

Thanks!

Found some 100PSI rated hose at Autozone.
GOODYEAR INJECTION HOSE

I have two 6" sections of it and let it run with the motor off for 15 mins with no leaks. /cheer

Sound safe? Would a braid over the hose help? I do have some braided hose I could steal the braid from and use for the TBI connection.

Thanks!

Went ahead and ordered the following to do it right. Listed them in order of connection.

AER-FBM2112 Fitting, Carburetor Inlet, -6 AN Male to 5/8-20 in. Male
AER-FBM1112 Fitting, Hose End, 45 Degree, -6 AN Hose to Female -6 AN
SUM-230603 Hose, Braided Stainless Steel, -6 AN, 3 ft. Length
SUM-220690B Fitting, Hose End, Straight, -6 AN Hose to Female -6 AN
SUM-220632B Fitting, Coupler, Straight, Male -6 AN to Male -6 AN
SUM-220634-2B Tube Sleeves, -6 AN, Pair
SUM-220633-2B Fitting, Tube Nuts, -6 AN, Pair