Need help with fuel supply for my Whipple install

[2quik4u]

I have a 1990 Z71 with a GM crate motor rated at 330/380
Here are the specs

Bore/Stroke 4.000" x 3.480"
Maximum RPM 5500
Camshaft Hydraulic flat tappet (part #24502476)
Camshaft Duration @ .050" 212° Intake/222° Exhaust
Camshaft Lift .435" Intake/.460" Exhaust
Compression Ratio 9.1:1
Pistons Cast aluminum (part #12514101)
Connecting Rods Powdered metal (part #10108688)
Crankshaft Nodular iron (part #14088526)
Cylinder Heads Cast iron Vortec 64cc (part #12558060)
Valve Size 1.94" Intake/1.50" Exhaust
Rocker Arms Stamped steel 1.5:1 (part #10089648)

I have a Whipple supercharger that I want to install. I am planning on running a 50mm ported TB and the 454 90lb injectors but have been told that they will not supply enough fuel for the motor and the supercharger. I already have a 255 fuel pump. Does anyone have any suggestions? I dont think any companies offer aftermarket injectors and the supercharger is only made to work with the factory TBI. Any help would be greatly appreciated. Thanks

[cancritter]

personaly am not a expert but from looking at your specs dont see any reason it wont feed your engine...your heads are your limiting factor here lm betting....

others with the know will speak up

[Aloicious]

I am no TBI expert at all, but with 90# injectors, you're basically getting a total of 180#/hr of fuel, that equates to approximately 22.5#/hr at the cylinder, which is a little low IMO, in my whippled setup, I'm running MPFI with 36# injectors at each cylinder (they actually run about 40# at my fuel pressure), though you might not need that big, I would think you'd want something a little bigger than what you've got. hopefully some TBI experts will chime in and let you know for sure.

[xch3no2]

Bumping your FP up 120# is possible from those injectors. It seems generally accepted that they will handle up to 30psi without problems. That limits the TBI to somewhere around 450hp, and covers the BSFC for your build. (expected HP x .47) There is a fist full of injector sizing & flow calculators online. Expect to invest in an EBL or emulator.

[whitelightnin92]

about 432 hp is wat i got just as a quick estimate. thats at 30psi. wich is plenty for your motor given you can tune it

[xch3no2]

I wasn't gonna say some guys use 35+ psi w/VRFPR (not for blown engines) that's getting a little "iffy" to me.
I hope Sean weighs in on this.

[whitelightnin92]

you can do the VAFPR thing but i was never too fond of the idea. if you need more than 30 psi then it time for two TBIs or a 4bbl tbi or mpfi

[907 Chevy]

Do yourself a favor and ditch the TBI.You might as well run a carb imho.If you'd like fuel injection,go with multi port.Better fuel distribution equates to more safe boost you can run.

[xch3no2]

Agreed, with white.

[2quik4u]

Thanks to everyone for the replies. I do not want to go with a carb. The Whipple is made to work with the TBI. I think it could be made to work with multi-port but that would probably get expensive fast. I would like to stick with the TBI if possible. The 454 guys run the Whipple with TBI so I think it should work. I want to run the stock boost level which is 5-7lbs so Im thinking 24-30#s of fuel pressure should support it. Any more input would be greatly appreciated.

[whitelightnin92]

you are going to need between 25-30 psi to fuel it. but dont be suprised if it still needs more. i would start with atleast 25psi though

[cancritter]

would get a Extreme tbi at 50mm..this will help ya out...or 454 one but Extremes will be new with shaved sides and new throtle bearings..
lotsa folks here use them includein me..
http://cgi.ebay.ca/454-350-GM-TBI-50mm-SBC-tbody-700cfm-Truck-SUV-Z28-TA_W0QQitemZ230429550353QQcmdZViewItemQQptZMotors_ Car_Truck_Parts_Accessories?hash=item35a6abe711

[whitelightnin92]

i got my 454 tbi from tbiparts.com. hes a member here. im happy with it. it was basically brand new(un ported tho)

[cancritter]

np..the 50 mm would be better but main thing here is the new throtleshaft ect...a worn throtle shaft and bushings will play havoc with the TPS and tuneing ect

[2quik4u]

would get a Extreme tbi at 50mm..this will help ya out...or 454 one but Extremes will be new with shaved sides and new throtle bearings..
lotsa folks here use them includein me..
http://cgi.ebay.ca/454-350-GM-TBI-50mm-SBC-tbody-700cfm-Truck-SUV-Z28-TA_W0QQitemZ230429550353QQcmdZViewItemQQptZMotors_ Car_Truck_Parts_Accessories?hash=item35a6abe711

Thats the one I was looking at. I have looked at the ones at tbiparts.com as well. They both seem like nice pieces. I will be ordering the TB and 454 injectors this week. I just hope they are big enough.

[cancritter]

bought my injectors here...may help...been awhile so not shure about prices
http://www.fiveomotorsport.com/

[xch3no2]

That's the Sean I mentioned (TBIparts), nice guy.