I was thinking about doing a c5 fpr swap, but now I'm wondering if I should just go with an adj fpr? I was thinking about replacing the factory flexible feed and return line that runs from the top of the fuel tank to the fuel filter so that it's future proof. I'm dropping the tank for some other mods that require it and I only want to drop the tank once. Some questions:

1. How long are the feed and return lines between the fuel tank and stock fuel filter location on a 99-02? Will 36 inches of flexible fuel line cover it for each line?

2. I want this to be future proof so if the end goal is 1200 rwhp in the future on E85, should I just run two 8 AN lines from the fuel hat to the c5 regulator or adj pres regulator for now, and use the stock hard line that goes from filter to the engine until the time comes to upgrade that hard line? I'll ditch the c5 regulator when the time comes / or move the adj fpr to the front of the car near the rails.

3. Does everyone just use 3/8" Female to 8 AN Male Push On/Quick Connect Fuel fittings for attachment of the fuel line to the fuel hat rather than run a -8AN bulkhead?

4. Should I just purchase 6 feet of Goodridge G-Line XF 811 hose then and make my own lines?

5. Right now I just have a single racetronix 255 and will upgrade the pumps when the time comes but would like to do the bigger fuel line upgrade now for the lines that run between the tank and the stock "T" fitting location. Using that pump and two 8AN lines to the c5 regulator /or adj fpr setup along with the stock hard line to feed the engine, will the fuel pressure at the rail be correct at 58 PSI?

 

Will this work, using cheaper fittings where applicable? Not sure if there's enough room to do a simple female -8AN to female -8AN to connect the filter to the regulator. Part # for that would be AT915108ERL.




6 feet of Goodridge G-Line XF 811-08 hose
13101 - Aeromotive Adj Fuel Pressure Regulator Dual -10AN in, -6AN return
SUM230118-B - Fuel Filter, Inline Mount, Billet Aluminum,100 Microns, -8 AN Inlet/Outlet
15610 - Aeromotive - Straight, Male -8 AN to Straight Cut Male -10 AN O-Ring (qty=2)
15649 - Aeromotive - Straight, Male -6 AN to Straight Cut Male -8 AN O-Ring
491992-BL- Fragola - EFI Adapter, Straight, Male -8 AN to 3/8 in. Female Spring Lock (qty=2)
15653 - Aeromotive Straight -8AN Hose End (qty=7)
15355 - Aeromotive - Hose End, PTFE, AN-8, 90°
9892086ERL - Earls - Flare Reducer, Female -8 AN to Male -6 AN
AT165006ERL - Earls - Fitting, Tube Adapter, Male -6 AN, to 3/8 in

Inside the bucket, the stock FPR is removed and an 8mm x 120mm Corrugated PTFE Flexible Fuel Pump Hose Line is used in it's place to direct the return fuel from the top of the hat to down in the bucket. Part number HFP-FH89-120-PX and comes with the 2 clamps.

Eventually when I'm over 700hp, I'll relocate the regulator to up by the fuel rails.

 

Honestly, just do an engine bay or rail mounted regulator. It'll give you the opportunity to easily adjust it, as well as monitor pressures. It's a far more convenient location and you'll never need to upgrade. Even if you don't, skip over the Corvette regulator.

If you can afford to, run all the lines full length of the car and get it over with now. If you don't want to do both right now, at least do the return system all the way to the fuel rail/regulator and then run an 8 or even 10an line up to the fuel filter and use some adapter fittings to use the OEM fuel filter or aftermarket filter of your choice. I'd just spend the extra coin and run it all now and be done with it.

But to answer at least part of your post, you would probably need about 5-6' to get from the pump hat to the factory fuel filter. Just being conservative. I'd rather have too much fuel hose than not enough. Also, quick connect to AN adapters are perfectly fine though of you're using the factory style fuel hat. I don't know if you really need to worry about routing any kind of return hose underneath the hat, so that it flows into the bucket. I've never heard anything about people doing that.

 

Yep, that makes much more sense. Might as well do it once the first time and do it right. So I'll run a return 8AN line from the adjustable fpr mounted in the engine bay directly to the top of the fuel hat. For the feed line, I'll run an 8AN from an aftermarket filter mounted in the stock filter location to the top of the fuel hat (approx 5-6 feet of line), and coming out the front feed side of the filter I'll run a line all the way to the front and use a 8AN "Y" splitter to enable me to run a line to each individual fuel rail. On the other end of each fuel rail, I'll run the 2 separate 8AN lines back to the fpr. The fpr will enable me to bring it to 58 PSI at the rail even though I'm running a smaller 255 pump through big 8AN lines, correct? No other concerns running bigger fuel lines with such a small pump for now? Is 8AN big enough for future target of 1200 rwhp on E85 or do I need to use 10AN? How many feet of line do you think is needed to run from the factory fuel filter location up to the fuel rails and how many feet for the return line running directly from the engine bay location all the way back to the top of the tank?

Details on the need for a return hose underneath the hat after removing the stock fpr were found here: https://ls1tech.com/forums/attachmen...s-img_1618.jpg

 

IMO - shy away from stainless outer shielding and use Aramid fiber outer shielding. Your best bang for the buck IMO is to get a kit (Racetronix) for the Fbody or order parts based on the inventory of parts supplied with fbody kit.

Some reasons- to use Aramid fiber shielding instead of stainless. Been there done that.

Fiber is not nearly as heavy as stainless.
Fiber is more pliable when making a 90 degree bend or any bend.
Because stainless creates more stiffness, more pressure and stress is exerted on the line and hose ends wherever there is a bend in the hose routing. That's when the line is empty. Consider the pressure exerted with fuel at 60 psi.
Fiber twice as easy to work with compared to stainless.
Fiber is easier to cut the hose when installing the hose ends.
Fiber is less likely to wear on other parts of the car unless completely isolated with hose standoffs. When you make the hose run IMO use standoffs to reduce wear and vibration.
In link below I had to use 45 degree fittings to make the bend because 8an stainless is so stiff.







Tips:

Since your total hose run is shorter, splurge for the higher quality PTFE hose that is extremely pliable especially if you get the Aramid fiber covering (compared to total hose length for an Fbody for example).
Buy hose ends hardware and hose that is compatible. The inner diameter and wall thickness of the PTFE hose has to be the same size as the hose end parts/hardware (the olive/compression ring). Get extras if the hardware uses an olive. The olives are not reusable. Some olives are aluminum, some are nylon.
8AN stainless PTFE (Racetronix) is extremely stiff when trying to make a 90 degree bend. Since a 90 degree bend or more with stainless is so stiff, this exerts pressure on the line and/or hose ends.
Get the tool that you insert in a vice to hold the hose ends when building each hose. It makes installation a breeze and keeps the hardware from nicks and scratches from the vice and wrenches used. AN wrenches as well - instead of using a Crescent wrench or metric wrenches.
Measure twice cut once.
Don't ever cut stainless outer shielding without wearing a face shield and safety glasses with a cut off wheel.
When cutting the ptfe line make sure to blow out the dust and crud that finds its way into the hose from the cutoff wheel and the hose. You will be surprised at what comes out after a cut.
Use a plastic wire tie and tape tie at the cut-line. The wire tie and tape will keep the fiber and/or stainless from fraying as you cut.
Shop around and compare prices. Racetronix hardware is competitive on pricing.

As for the C5 filter.

I would replace it with the big filter from RaceTronix or Fuel Lab. It will come with the kit if your order a fuel line LS1 kit from Racetronix.

According to testing by a vendor on this forum, the latest version WIX C5 filter with the built in regulator is the most consistent in maintaining 58 PSI.

One thing that doesn’t get mentioned much is whether over time how compatible the C5 filter is with E10-15/E85. When does the paper filter inside start to break down?

If you decide to keep the C5 filter for awhile, check the size of the return outlet on the filter. I recall it’s 5/16 inch – not 6an (3/8). If so unless there is an enlarged adapter the stock return line is also 5/16. What’s the point of an 8an return line if it is bottle-necked at the inlet on the fuel hat that is only 5/16?

On the fbody fuel hat the return line inlet is pinched down to 5/16 and then enlarged to 6an as it enters the tank. Check your sizes when ordering the quick connects at both ends on the return line assuming you don't buy a complete kit.

On my fbody I cut the return 5/16 line restriction off and installed hardware that is 6an.




The Fbody kit - 740 lph (8an feed - 6an return - 30 ft total)

Verify hose routing at the rails with the Fbody kit. The fbody kit feeds the rail once in and once out. It doesn't come with extra fittings so the feed can be T'd into both rails in or out. If you want two in and two out you need more fittings. Talk to tech about this?

Quick Connects

Racetronix has metal quick connects. Almost foolproof from coming apart.

From my experience however, is that they are difficult to take apart because the tolerance’s are so tight. Mine were almost impossible to take apart once installed. The metal quick connect is also hard to take apart depending on location of the quick connect. So make sure you remember the wrench size when you install and remove the retaining nut on the quick connect. If you can’t use a wrench to remove the retaining nut use the nylon retainer quick connects instead.

 

Hm, I didn't do any kind of return hose in my bucket. The fuel coming back in is low pressure and should drop right back into the bucket. It won't hurt though, so if you'd prefer it then I'd say do it.

As for the lines, a 10AN would probably be a good idea for the feed line. 1200whp on e85 is A LOT of fuel. I used at least 15' running my 6AN return line from the tank, through the tunnel, over the trans, and to the front of the passenger side fuel rail. I decided not to Y my feed line into individual rails, but my fuel system isn't setup to handle 1200+. 20' of both 8 and 10AN should hopefully be enough, so long as you do the Y as close as you can to the rails. It sounds like you also want to run the return after the fuel rails get fed, if I'm reading correctly, which is good.

Running that ptfe is a bitch FYI. It's not very flexible, but it's necessary to use. It'll be expensive, but you gotta pay to play.

I don't know about the whole using a 255 pump on that kind of line though. I can't say I've heard of someone doing it. In my head, I'd say no, but you need to talk someone who has more experience with fuel systems for that.

 

Great info! Thanks again!

 

Some useful info here (1200 rwhp). When reading this can't image the return inlet on the stock Fbody fuel hat is large enough for 8an when running E85.

https://www.corvetteforum.com/forums...00-rwhp-2.html

 

I can't see it being large enough either. Would have to run a bulkhead.

As for hose, I've been reading good opinions on braided Nylon Fiber hose with FKM Flourelastomer liner. Won't get eaten by E85. Has thin stainless steel braid underneath. 500 PSI, can handle temps up to 275° F.

 

If you want some nice fuel hats, complete assemblies, or just anything customized to your liking, John Smith out of Humble, TX can get you the parts to move a lot of fuel and do it for very fair prices. You can find him on Facebook. If you just wanted some bits and pieces, such as a really nice pump hat with ports big enough to handle big fuel, I'm sure he'd help you out. You could always just modify the factory hat too though.

You could run an 8AN return for now on the factory hat since you won't be moving much fuel. But yes, it would definitely be a necessity to upgrade the return inlet if you wanted to make the numbers you mentioned.

 

See link below. Pricey - but extremely pliable and flexible. If you T or Y the feed line at the rails and return line, plan on about 32-34 feet.

https://www.pegasusautoracing.com/pr...p?Product=3490

IMO build the return line first, then use what's left over for the rails. Build the feed line last because you split it dependent upon where you install and splice in the huge fuel filter. Since the hose in the link is so pliable it's easier to route compared to 8an/10an PTFE stainless hose. The 90 degree bend needed to route the feed up to the rails on the driver's side takes more linear ft. I probably should have tried to route the feed line on the passenger side instead of the driver's for the pathway up to the rails.

I'm tempted to replace my feed line with this. I still don't like where I had to install the huge filter. Since this hose is so flexible the filter will be easier to relocate as well.

Installing the fittings can't get much easier compared to the typical red/blue fittings or those fitting that use an olive/compression ring.

https://www.pegasusautoracing.com/do...ocID=TECH00026

 

32-34 feet total to run both return and feed lines then?

$33 a foot for 10AN? That's like triple the price of the standard PTFE but I bet it's hassle free to work with.

 

The Racetronix Fbody kit includes 15 ft PTFE hose of each size - 8AN and 6AN. However their rail kit includes fittings for one inlet and one outlet. So if you Y the hose for the rails it will take more hose and fittings. At $10 - $35 per foot you might want to measure accordingly with string, rope etc The return line will be less in length than the feed line because it runs from the FPR back to the tank.

The Fbody wheelbase is 101.1 inches. Total length is 193.5 inches..

The problem with PTFE is that if you bend it too much it will kink and you can't see the kink because it will be hidden under the the outer shield (stainless or fiber). Not so much with convoluted PTFE inner liner or Aeroquip hose that is not PTFE.

https://www.aircraftspruce.com/catal...iABEgLd-_D_BwE

The pressure points that I found was looping the hose so it wouldn't kink was up to the tank in the rear and up to the rails between the body, steering wheel shaft, and exhaust collector pipes in the engine bay. To avoid kinks you have to create a gradual loop when routing the lines. The specs tell you the maximum arc when bending the hose. Exceed that limit and it might kink. Same for the return line from the FPR arcing it in the engine bay back to the fuel tank. You don't want the exhaust collector pipes next to the fuel line. I tapped my return line into the feed line. You won't be able to do that if you run 8AN return line.

See pic.






One issue I found with the RaceTronix kit were the fittings for the rear of the fuel rail on the passenger side. The supplied fitting interferes with the transmission dipstick tube (A4 only). So I had to get a straight fitting and gradually loop the line along the firewall.

Don't make the mistake of cutting and installing the hose end fittings and then find you have to do it over. The fittings are reusable. The compression rings (olives) are not .

The break point for cost with E85 appears to be when you exceed the 800 rwhp level - pumps, fuel line, tank, bulkhead for fuel cell, rail kit, dual wire harness' etc.

 

What about the plumbing on the top of the fuel hat? I see that people have modified the stock bucket with a 10AN bulk head fitting on the top, which then splits inside the bucket to dual 450s. That's all good, but then they have a 6AN return line using one of the factory ports on the top. Isn't another 8AN bulk head fitting needed on the top of the hat for the return, or is it OK to run 8 AN return all the way back to the tank and have it bottle neck at the fuel hat down to 6 AN? And what about the FPR return inlet? An Aeromotive 13101 for example has two 10AN feed, and a single 6AN for return? Do people just run a 6AN return all the way back or do they use 8AN line and again have it bottle neck at the 6AN inlet of the FPR? Something like this perhaps, but how much rwhp can dual 450s on E85 support?

 

If your goal is 1200 rwhp might want to visit the Corvette forum and/or other forums and start doing a lot of research. I made a lot of mistakes simply trying to build a system to handle 6 to seven hundred rwhp. And it still needs work because it's a 98 Fbody which has it own set of problems.

Some of the issues to address for 1200 rwhp.

https://www.dragzine.com/tech-storie...eans-big-fuel/

 

Good article! Thanks for posting.

So they estimate 1080 lbs per hr of fuel is need for 1200 rwhp flywheel hp on E85, but then go on to say that what is really needed is 1250 lbs/hr at 70 PSI. Density of E85 is 6.5 lbs per gallon, so we are talking 192 gallons per hour needed. One walbro 450 puts out 94 gal at 70 psi at 13.5v, so if two of them are tied to a Y with two 0.375" (3/8") inlets and a single 0.56" (10AN) outlet, thats still 188 gal per hour and not enough fuel considering we are talking 1200 rwhp and not flywheel hp. Seems like that 5 gpm aeromotive pump with built in TVS controller and just running a sump to the tank itself is the way to go at that much HP. Now if it was 1000 rwhp on E85, then the dual 450 setup should theoretically be enough.

 

There is a scientic principle. As fuel pressure increases volume decreases. So in order to maintain volume you have to increase pressure.

Not a big deal when you are building a fuel system for 5 to six hundred rwhp and just running 15 lbs of boost. It's pretty much plug and play with lots of over the counter parts availability. But if you want 1200 rwhp you have a lot of homework + you need deep pockets.

For example: the GM tech that helps me with my Camaro has a Dr son. They built an 8 second 99 turbo'd Camaro. The son just recently sold the car for $45k and lost money on it. The things he had to do to his Camaro compared to mine with his build is night and day difference. It was only making 1000 rwhp. Your goal is 1200 rwhp.

IMO shoot for 7 - 800 rwhp max and wait on the goal of 1200 rwhp.

 

That's the plan. A 1200 rwhp build on a 4th gen costs about $50k to do it right. Trans, rear end, fuel, power adder, chassis work... it all adds up really quick.

 

Well this certainly takes the guess work out of it.

http://rs-enthalpy.com/tuning/turbocalc.xls