With going single and upgrading your fuel set up, is there a real difference with using -6 lines vs -8? I ask because the kit i bought used both and i want to make it all one size. Im leaning towards making it all -8 since majority of it is -8.

 

Unless you change the size of the feed from the tank to the engine bay, there is no difference really.

 

Like Monkman said, if you're keeping the factory hard lines in place from the fuel tank to the engine bay then it really won't make that much difference. If your replacing ALL the lines then, in all honesty, -8 is still a little overkill unless you're bracing for some pretty intense fuel consumption...

That being said, when I swapped all my lines out I went with from -8 the tank to the engine bay, then added a Y-fitting with parallel -6 lines. -8 isn't necessary, but it shouldn't really hurt either.

 

I see. Im keeping the stock hard lines from the firewall to the tank. The engine bay lines are getting the upgrade. Im going to be using the supra pump with 550s and 1680s. My concern is going from a small line to larger line going to be a problem. Whoever had the kit before me was having success using the -6 and -8 lines at the same time.

 

I would just save the money. I am going -6 after the firewall. For your injectors, no reason to go bigger unless you've already spent the money.

 

Lol well.............. its not that i spent the money but i did sell the -6 fittings already in anticipation of buying the remaining -8s. Pretty much a fail on my part that im asking this after the fact. So i guess in a way the money is already spent =/

Is a smaller line feeding a lager line a problem or can cause problems? I may be overthinking it but i see it as a small straw going to a large straw. The amount of fluid coming out of the small straw isnt enough to fill the space in the large straw. That empty space is air. Fuel injectors pumping air instead of fuel doesn't sound like a good time.

 

Nah. You'll be fine once it's all primed.

The injectors dont inject more than the smallest line. It will all fill with fuel and be pressurized. You wont have any issues as long as you dont go with too much injector and power for the weakest/smallest link in your fuel system.

:-)

 

Great. Thanks for the help

 

one more question... when using an aftermarket secondary rail, what do you guys do about fuel temp? is it worth tapping the rail to install? does it matter? im going to be on a power fc.

 

I didn't and know most people don't bother with it. Doesn't affect anything and I doubt you'll see very dramatic temps unless you're running a complex set up.

 

Cool. Thats good to know. Thanks

 

Good info , I'm working on my fuel lines too on my 1st gen and that's exatcly what I'm facing thanks.

 

Warmer fuel atomizes better.

 

-6 is fine unless you plan to exceed 500 whp. Then you need to start thinking about upgrading from the tank forward. I wouldn't waste time with the 1680s. They are old technology. The newer EV14 and ID injectors are far superior in atomization, spray pattern, and tuneability.

 

I see, well i already have the 1680s. They came with the kit. Others have used them with success.