Should a big line kit (filter can to inj. pump on an '01) be "matched" to the mods, etc. on the engine? Or is this a case where bigger is just plain better? The reason I ask is that I see a vendor offers a 3/8" kit and a 1/2" kit both for the same price. If this is one of those things that can't be too big, then it makes sense to get the 1/2" kit incase future upgrades were made... it would already be done.

 

The important thing is to keep your fuel pressure in the correct range at your injection pump. The pressure restriction comes from the inside of the pump which is much more restrictive than your lines(the banjo bolts are more restrictive as well). If you go to a bigger line, fuel will simply flow more slowly in it given the same operating conditions. You will not hurt anything by going to a bigger line, just keep the pressure correct. That being said, 1/2" line will flow an awful lot of fuel. I would think that the rest of the restrictions in the fuel system couldn't keep up.

 

1/2 stuff is hard to find around my area. it flows really good but if i change stuff on my set up like a different pump or add a better pre filter set up its hard to find 1/2 but 3/8 you can get that stuff any where.

 

FWIW, the fitting size on the IP and filter canister is 12mm, which is likely a 9mm ID, roughly 3/8"

 

While we're on the subject of fitting sizes.... are the fittings on the stock Carter lift pump also 12mm? I'm going to do a little reworking of things in that area too and want to make sure I order the correct size fittings.

Thanks...

 

I have 3/8 line running from the tank to the FF canister and a Vulcan 1/2 stainless braided line running from the canister to the VP.
You can get adapters to run the 1/2 or 3/8 line from the canister to the VP.
IMO, unless you are running a high HP application you would be OK with the 3/8 line. I just went with the 1/2 stainless braided line cause it looks sexy.

 

There's no real downside to 1/2" on the inlet side of the pump. You can see lower pressures on the outlet side if using a low volume pump. Usually a pound or so.

I have modified the fittings in my truck to be 14mm. Really helps with flow, but you can only move so much fuel anyway. There is no performance advantage at all, it was done for testing flows, pressure drop and refill rates at a given pressure.

Dave

 

To answer your question on fitting size. The fittings on the stock fuel canister, the stock lift pump, and the injection pump input are all 12mm. The exception is the pressure relief on the return line side of the injection pump.