Which Fuel Pump / FPR?
 

'95 LT1, Stage 3 Heads (2.02/1.60 w/ beehives), somewhat aggressive cam (between cc305 and cc306), and some of the other typical bolt-ons... I don't really have much more planned for it anytime soon.

I have about 105k and 11 years on the stocker, and I think the first couple runs on this new setup killed it (big surprise).

What kind of fuel pump do I need, and do I need a new FPR for my setup? I don't know much about fuel stuff, but I hear it's kinda important :)

Re: Which Fuel Pump / FPR?
 

Odd to see no replies!? How about we approach it this way... I've been told the Walbro 155 is enough. I also see Holley makes a 155.

Question 1 - is 155 enough for my setup? It seems to be from what I've read.

Question 2 - Holley or Walbro?

Re: Which Fuel Pump / FPR?
 

You don't need a new fuel pressure regulator.

155lph seems a bit on the low side.

You think it should make 450 flywheelHP?

450hp X 0.48 #/Hr/HP = 216#/Hr

216 #/Hr / 6#/Gal = 36 Gal/Hr.

36 Gal/Hr X 3.78 Liters/Gal = 136 LPH.

Assume as least a 20% bypass quantity....

136 / 0.80 = 170 LPH

I run a 205 LPH Bosch pump that's comfortable at 500 flywheel HP.

Are you sure you don't mean the 255 LPH Walbro or Holley?

Re: Which Fuel Pump / FPR?
 

i havent had good luck with the walbro 255. the stock lt1 pump is 190lph i think. should be fine for heads/cam. thats what im going back to since after a year and 6K miles my walbro 255 **** out on me.

Re: Which Fuel Pump / FPR?
 

I'm probably mistaken, yes. Even though Thunder Racing's page showing the Hollleys rate the 155s to 491HP? ( http://www.thunderracing.com/catalog...vid=4&pcid=165 ) Yes, I'm hoping for 450hp at the flywheel and building it for 500hp would be safe (I don't ever see reaching that without a complete rebuild).

But, those calculations are awesome, I'm definately keeping those handy. Is there any downside to buying a bigger fuel pump than needed? I don't mind the extra $50-70 so if buying a 255 is plenty with no downside consider it done.

So do you recommend the 205 Bosch, 255 Holley, or 255 Walbro? I've heard mixed things on the Walbros but don't know anything first-hand...

Re: Which Fuel Pump / FPR?
 

The numbers published for fuel pump HP capacity are VERY misleading. Look at the numbers shown for the 155 LPH Holley. It says it can flow 246#/HR to support 491HP. But that only works out if the pump is operating in a system that does not require "recirculation". Our LT1 fuel systems are recirculated systems. There must always be a flow of fuel back to the tank, so the fuel pressure regulator can close down on the return flow to hold the pressure. That's why I divided your engine's fuel requirements by 0.80..... that provides a 20% excess flow that gets returned to the tank.

And, they tell you what HP the pump can support, but they don't tell you what pressure its supplying the fuel at. For the type of pumps used to pump fuel, as flow goes up, the pumps pressure capability goes down. Or looking at it another way, that pump may flow a huge amount at 20psi, but drop off in a major way at 43.5psi. There is not enough info in the Holley ad to allow you to pick the right size pump.

My personal choice for a fuel pump is the Bosch 205 LPH. I run a pair of them. One has supported 500flywheelHP running NA. With the second one running, I've pushed 800fwHP with a 300-shot of nitrous, dry system, running 78# injectors. One of the Bosch pumps came as the inline booster in an NOS dry kit that I bought 11 YEARS ago, and its still going strong. The shop that built my engine uses them whenever they can. One Porsche Turbo (close to 30# boost) they were setting up had a bank of four of the Bosch pumps, side by side, capable of supporting 2,000HP.

Accel sells the Bosch pump with their logo on it, and they rate it at 750HP. It is not a 750HP pump.

Re: Which Fuel Pump / FPR?
 

Awesome info Injuneer, that all makes perfect sense and I understand them a LOT better now. Thanks so much for taking the time!

Craig