Upgrading the stock fuel line on a returnless setup

So we did this upgrade on Greg's car as he is pushing some big power on a returnless setup and after what we found decided to do it to mine. I think its something often overlooked when trying to get alot of power out of a returnless setup and these are all items removed or upgraded on return setups. While you can always get away with baps and biggers pumps this is one thing that at least deserves a look when trying to get the most out of your returnless setup.

The size of the line itself isnt the biggest offender. The stock line connector to the rail and pprv are 2 choke points at both ends of the system.

First is the stock rail line connector, while the line is indeed 5/16" id this all gets choked down by a 1/7"(4mm) outlet to the rail. Here it is next to an 8an line.





If your looking to keep the stock rails but want to get rid of this restriction you can find aftermarket spring style efi connectors with a larger inner diameter. Here is a picture of a fitting made by russels I found on the web.







And then theres the pprv in the fuel hat. It's sole purpose is to make cold starting easier by maintaining fuel/pressure in the rail while the car is off. Nothing a key on or two before starting cant solve. The pprv is right inline at your pump(s) outlet and immediately restricts flow, here are some pics of the size and internals of it. I would reccomending deleting it when going past 600rwhp.




And cut in half to see the check valve internals



The pprv valve delete alone is worth a 2-4% drop in duty cycle and also helps prevent pressure spikes and drops at shifts. When you let off the gas to shift(if you do lol) the injectors lock and pressure spikes as the check valve keeps the pressure from immeditley flowing back. The frps sees the spike and the pcm reduces voltage, by this time your already back in the gas and the demand from the injectors is back and you get a pressure drop. This is a must do mod for the 99-04 cars and termi's but is often overlooked on the s197 Gt's and Gt500's.





The stock fuel filter also leaves much to be desired when pushing more power, here are some pics of the stocker next to the Fore filter which is 10 micron, has 10an ports and is rated to 2500hp.



And here is the filter with a 8an line fitting installed.



Here it is installed in the stock filter holder.




Here is what we did at the fuel hat to maintain the quick disconnect fitting. The plastic stock fuel hat connector is 5/16" the crossover style connector in the tank with a green lock tab is 3/8" so slightly bigger so we clamped the 8an hose to the 3/8 fitting.







And last is a shot of the hard line under the car going from the hat to the engine bay next to the 8an hose.




We did this same swap on Greg's car at the shop at Im going to get some before and after data as far as pressure and pump duty cycles and I will post that up.

Very good info Jeremy! I was wondering how you did the conversion to the GT500 hat.

Edit...

I see in the last couple pics the extra electical lugs you made in the hat. Are these necessary to run two 405s in the GT500 hat?

Thats just something custom I did on my car awhile back, its a stock GT hat and the terminals I installed allow me to run 10awg power/ground wires directly to the pumps from the fpdm's.

Jeremy, is it possible to cut off that restriction at the stock line connector? Reason I ask is because for my build I need to run a new fuel line from there to the rails.

Chino said:

Jeremy, is it possible to cut off that restriction at the stock line connector? Reason I ask is because for my build I need to run a new fuel line from there to the rails.

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Yeah its possible there is another of these connectors from the rubber line in the engine bay to the hard line right behind the drivers side strut you could run a new line from there to the rail or just go from the fuel filter to the rail its only a few feet more of hose.

FYI it only took 10 feet of hose to run from the tank to the rail with some wiggle room to spare and route it how you want. I ran the new line right along the exsisting line and left the stock line there.

Any chance a kit will be available soon?

Where are you buying the line? Just curious who you are using. Going to go return style soon. This would actually be a step in the right direction as it could all be used in the return setup as well.. Nice.

Also interested in what all was done when you removed the PPRV.

The fore kit that S&H sells already has the PPRV deleted. Here is a link to their full return setup....

http://www.s197forum.com/forum/showthread.php?t=88971

AutoXRacer said:

Any chance a kit will be available soon?

Click to expand...

Yes I can put a kit together for your needs/setup.

crownaviation said:

Where are you buying the line? Just curious who you are using. Going to go return style soon. This would actually be a step in the right direction as it could all be used in the return setup as well.. Nice.

Also interested in what all was done when you removed the PPRV.

Click to expand...

Its aqp (Aeroquip) startlite kevlar/nomex line from Fore, same line they use in all their kits.

http://www.foreinnovations.com/product_p/aqpk.htm

Exactly this gets you halfway towards a return setup anyway if you decide to go return later you just need a fpr and a return line to complete the system.

I just cut it out and used some submersible hose and clamps in the hat where it use to be.

Can you put together a kit using the stock rails, running a -6 from rail to where it enters the engine bay with the correct fittings? The DOB manifold requires a new fuel line so this would make things a lot easier for their users.

Yeah if you guys want a quote on lines and fittings for your setup just let me know. You would just have to source a few clamps or an efi fitting. Here is the link to the russell connector to run a 6an line to the rail, they also make one for an 8 an line as well. I would personaly run an 8an line if your gonna upgrade, upgrade lol

http://www.amazon.com/Russell-640903-Specialty-Adapter-Fitting/dp/B002Q3EPZK


Here you can see this fitting on a 6an line

So basically the issue with the OEM line above is the connectors that create a restriction?

The upgraded line below it, uses less restrictive connectors...?

Where can I buy and how much would this replacement line cost? Would it be a straight "bolt-on"?

The only thing left would be the fuel filter restriction and the PPRV?
What would you say the biggest restriction is?
-Fuel rail supply line
-Fuel filter
-PPRV

And lastly, would you have to retune the fuel maps (tune) if you were to do these mods?
Do to the increase flow, does it affect a tune written with a 100% stock fuel system...?

Based on what we saw the stock line to rail connector (there is another one of these connectors behind the driverside strut tower) and pprv are the biggest restrictions since they are all smaller than the line itself. The line below uses a russell ford efi connector which has a much larger inner diameter. This is a pic of the oem rail connector and russell rail connector side by side.




You could try to replace indivdual things or just upgrade the whole thing which is easier. I just left all the stock lines in place and routed the new line so they are there if you ever want to change it back. The stock 5/16" line itself is not all that bad but saw no reason to keep using it while doing the upgrade. For reference: stock line id is .3125", a 6an line id is .375 (so just bigger than stock with out all the transitions and connections the stock lines have) and 8an id is .5" hence why we used 8an line for the uprgade. Not to mention the price difference from buying 6an or 8an line isnt that much. No you dont need a retune this upgrade just makes it easier for your pump setup to get fuel form the tank to the injectors/rail so a drop duty cycle will be seen and you will extend the range of the system.

For guys running 500-600rwhp+ I would start looking at this kind of upgrade to get more out of your fuel system.

Cool... Where do I order!!!!???

If it does not change tuning in any way, then I want one!!
I am shooting for 800HP or so... 700rwhp.

So I guess this is highly recommended in my case.
I'm just a little leary about the PPRV part... Did you say you only remove this part and replace it with a new line (R&R)?

Yep just bypass pprv with submersible line on the hat

Looking good

The oem setup uses plastic corrugated hose here. You would just cut it out and route submersible fuel hose and clamps where it use to be.

Here are pics of the pprv on a gt500 hat, there are barbed fittings under the plastic hose cut the plastic hose away on both ends and then run the rubber hose over the barbed fittings and clamp them on each side. The submersible hose it's 5/16" 30R10 hose.

Nice write-up. I have -8AN lines from front to back, with a -6 fitting at the fuel hat, but hadn't considered removing the valve in the basket. I'll do that next time I'm in there. Thanks.

Is it just me or is that orange flex tubing they use a MTHRFKR PITA to deal with? What is the trick? Heat gun? Did I mention I hate that shit.... I think I would rather drop the FORE hat in rather than deal with that crap again lol.

Looks good Ray, yeah I would ditch it when you get a chance. Im sure I will be doing something similiar eventualy and adding a return fitting to make a return setup using a stock hat or gt500 hat setup. I'm considering running the return down the passenger side and doing a return fitting into that side of the tank same basic way you did that setup.