From the beginning I had planned on replacing the stock fuel lines as part of my LS swap, but over the weekend when I pulled my TPI motor out, I started staring at the stock TPI fuel lines, and I realized that the high pressure feed line is a pretty damned big line. When you combine that with the 58PSI pressure that the LS motors use, I couldn't help but wonder if maybe my stock fuel lines are large enough. Rather than mount my Corvette regulator near the back and running all new line, now I'm wondering if it's not smarter to mount the Corvette regulator closer to the engine bay and utilize the existing lines, provided they can provide sufficient fuel.

What says the peanut gallery?

 

i am still running the stock fuel lines and hoping for my car to make 550-650rwhp on the dyno.

 

Stock hardlines are what 3/8" supply 5/16" return? If you have enough pump, they will support 1000hp.

Key is having enough pump. -6an line is 6/16 or 3/8 as well...latemodel guys with dual pumps have done 1000hp with those lines. Also read that late model vettes/GTO's and such have 3/8" line but not 100% sure. Seen alot of those guys make near 1000hp with stock hardlines as well.

 

Cool. That being the case, do you care to describe how you integrated the FPR? I'd like to at least cut back the lines near the firewall and mount the Corvette FPR down low on the firewall in order to clean up the engine bay.

 

Would this apply to the tbi hardlines as well? not sure if there was a size difference.

 

Good to know! I've got a 255lb/hr Walbro, so hopefully I have "enough" pump, but there's always the dual pump option down the road if I decide to spray, although now I'm starting to look at some of the new 340lb/hr in-tank pumps as an option so I don't have to upgrade later.

I guess now I just need to find a good place to mount the Corvette filter/regulator.

 

Hello Jim85IROC. I like your Iroc btw!! Funny that I ran across this as I started a thread last night about the location of the corvette regulator. I was worried about the length that the "regulated fuel" had to travel but everyone felt that I would be OK. I have to get new fuel line because my car was carbed originally.

 

I'm still debating on where to put the regulator myself. Some guys on 'tech (including some whose opinion I highly trust) feel that the closer to the rails it is, the more consistent it will be. Others seem not to care. It would probably be easiest to tuck it up near the tank and just keep the one line up to the front of the car, but if I can find a nice convenient place to stick it under the steering linkage near the firewall, I'll probably aim for there.

 

I saw a thread somewhere where they put it in the bay. It wasn't really much of an eye soar either. And it'll be convenient to replace if you get a bad regulator or 2. Lol

 

As ORR stated, the lines are not the problem. Not enough pump is. When I first done my swap, I used the 255 Walbro/Racetronix pump. When I ran it on the dyno the fuel pressure started to fall around 5000RPM and it was making 400 RWHP. Wasted dyno session! I then installed a Bosch pump from a twin turbo Toyots Supra. It kept 60PSI all the way to 6600. It's larger than the third gen pump but it CAN be installed onto the third gen sending unit with a little fab work. I ran aftermarket fuel rails & regulator for a true return system. The main line goes to the front of the pass side fuel rail, the crossover is at the rear of the fuel rails and the regulator is at the front of the driver side fuel rail, then to the return line back to the tank. Here's a pic of the engine bay.