Running larger fuel lines

**nsxinohio** · 06-02-2012, 13:38

I am in the process of converting my nsx over to e85. Have the fuel pump, injectors, and regulator all figured out, but trying to figure out how to run bigger lines. My old setup was -6an feed and return lines into the stock locations. I am thinking that would not be enough fuel volume to run e85. Will just single -6an feed to stock locations work or should I run -6an to each rail and -6an returns out of each rail. really stuck trying to figure this out so any help would be great. thanks

**Hugh** · 06-02-2012, 13:47

When the "ethanol fad" is over and they stop blending that crap with gasoline will it be easy to convert back?

**nsxinohio** · 06-02-2012, 13:56

e85 is just a lot cheaper than race gas and readily available where I live. If that day does come, the larger fuel volume wont hurt the car. I can switch back to race gas or pump gas without changing anything

**Hugh** · 06-02-2012, 14:24

E85 does have a higher octane rating than gasoline but it also has 30% or so less energy content. Does that affect the performance of the engine in any way or is it compensated for by using more fuel?

**hybrdthry911** · 06-02-2012, 15:02

Originally Posted by Hugh

E85 does have a higher octane rating than gasoline but it also has 30% or so less energy content. Does that affect the performance of the engine in any way or is it compensated for by using more fuel?

To the OP what are your horse power goals?

**nsxinohio** · 06-02-2012, 15:55

I made 564 on race gas and just looking for same results on e85. Motor is built has more in it but wanted to run a safe tune and make it streetable

**hybrdthry911** · 06-02-2012, 20:44

Originally Posted by nsxinohio

I made 564 on race gas and just looking for same results on e85. Motor is built has more in it but wanted to run a safe tune and make it streetable

Personally I wouldn't hesitate to run that on pump gas on a built motor as long at the setup is designed properly and efficient...but thats me. It seems people are worried about 420whp+ without meth injection/race gas. I think it wouldn't be a bad idea to have the lines tee off and go to each rail and then back together after into the regulator. The -6 will most likely be fine at your power level, but it wouldn't hurt to use -8 from the pump to the tee. What pump(s) are you using?

**nsxinohio** · 06-03-2012, 05:10

The aeromotive 340lph. I am going to try and tap the one end of the rail so I can run -6 feed for each rail and then tee the return lines from each rail into my regulator. Hoping the drill and tap part will go smoothly. Anyone know how are it is to drill that little plug out and then tap it?

**jorligan** · 06-03-2012, 05:12

If I remember correctly, the T is the problem. The factory T can be the restriction. You should run individual lines. AN-8 would be safe but AN-6 would probably be OK.

**DDozier** · 06-04-2012, 07:20

Originally Posted by nsxinohio

The aeromotive 340lph. I am going to try and tap the one end of the rail so I can run -6 feed for each rail and then tee the return lines from each rail into my regulator. Hoping the drill and tap part will go smoothly. Anyone know how are it is to drill that little plug out and then tap it?

If you can weld it is easier to just drill the ends of the passenger side of the rails and weld in -6 fittings. then use the old crossover lines for the dual returns to the regulator. Here is a drawing I put together for another member that was doing a similar setup.

Hope this helps.

Dave

**EAC** · 06-04-2012, 08:49

Originally Posted by nsxinohio

I made 564 on race gas and just looking for same results on e85. Motor is built has more in it but wanted to run a safe tune and make it streetable

You should make more power. I switched from VP C16 to E85 and made over 50 hp more att he same amount of boost. This was on a previous RX7. Also, it spooled up quicker..

**Gary W** · 06-18-2012, 17:12

Originally Posted by DDozier

If you can weld it is easier to just drill the ends of the passenger side of the rails and weld in -6 fittings. then use the old crossover lines for the dual returns to the regulator. Here is a drawing I put together for another member that was doing a similar setup.

Hope this helps.

Dave

I did this upgrade on the fuel lines.

No more banjo bolts, except at the gas tank.
Dave, thanks for the drawing.

Gary

**adrenaline_nsx** · 06-19-2012, 10:36

very nice gary..Im in the process of doing mine. Thinking about taking it to machine shop and getting the fuel rails bore out to a larger diameter while Im at it. Im not sure how big the stock rails are but do any of you think this would be unnecessary?

**DDozier** · 06-20-2012, 04:40

Originally Posted by adrenaline_nsx

very nice gary..Im in the process of doing mine. Thinking about taking it to machine shop and getting the fuel rails bore out to a larger diameter while Im at it. Im not sure how big the stock rails are but do any of you think this would be unnecessary?

It would all depend on your power goals, and I do not know the actual size of the opening in the tube now, but if it is bigger than the supply line feeding it it will not matter. There may also be some limitation to opening them up as the new larger diameter could cause issues with the upper injector o-ring seal. You would have to do some serious checking before you take a chance of ruining a rail. I am thinking unless you get to over 600whp the basic fitting mods and new dual feed line setup should be all that would be needed.

Dave

**jaffaz32** · 11-16-2012, 02:26

Very cool like the braided lines.

What size are they and which brand?

did you use the same size for both the oil and fuel? if not please specify what size and why this size? is there a rule? X size for X amount of power?

Originally Posted by Gary W

I did this upgrade on the fuel lines.

No more banjo bolts, except at the gas tank.
Dave, thanks for the drawing.

Gary

**Gary W** · 11-16-2012, 03:34

Thanks for the comments.

I used Russell lines, -6 for the fuel and -8 for the oil catch can lines.
You could use larger fuel lines but at my power level that was not needed.
It is good to get rid of those banjo bolts, to restrictive.

Gary

**jaffaz32** · 11-16-2012, 05:51

Originally Posted by Gary W

Thanks for the comments.

I used Russell lines, -6 for the fuel and -8 for the oil catch can lines.
You could use larger fuel lines but at my power level that was not needed.
It is good to get rid of those banjo bolts, to restrictive.

Gary

Cool, does look good.

I'm curious what power your running.

What type of fuel filter did you run with?

Did you go straight from fuel pump or enginebay only?

Something i would like to do myself.

**Gary W** · 11-16-2012, 12:57

Originally Posted by jaffaz32

Cool, does look good.

I'm curious what power your running.500 +

What type of fuel filter did you run with? System 1

Did you go straight from fuel pump or enginebay only? fuel pump

Something i would like to do myself.

Gary

**Elite** · 11-16-2012, 19:33

Originally Posted by Hugh

When the "ethanol fad" is over and they stop blending that crap with gasoline will it be easy to convert back?

Not sure the fad will end as long as it's being produced. It's pretty much taken over in the world of HP. With VP fuel prices going sky high, it's a no brainer to run E85 when running higher boost levels(any boost levels really). But if needed, no big deal to run pump or other race gas after being setup for E85.

Originally Posted by hybrdthry911

Personally I wouldn't hesitate to run that on pump gas on a built motor as long at the setup is designed properly and efficient...but thats me. It seems people are worried about 420whp+ without meth injection/race gas. I think it wouldn't be a bad idea to have the lines tee off and go to each rail and then back together after into the regulator. The -6 will most likely be fine at your power level, but it wouldn't hurt to use -8 from the pump to the tee. What pump(s) are you using?

Agreed(other than a "Y" would be better).

Just do not run one line to the stock location, you need to modify the path and supply both lines(rear bank will run lean otherwise). There are different ways to do this, and this thread covers most of them. Rather than tapping, I'd weld on the desired size fittings instead. And I don't think you need to machine out the rails at these power levels.

On my personal car I have separate lines from the tank(-8, one from each pump), to custom rails, to a FPR, running E85.

**hybrdthry911** · 11-16-2012, 22:13

Originally Posted by Elite

Not sure the fad will end as long as it's being produced. It's pretty much taken over in the world of HP. With VP fuel prices going sky high, it's a no brainer to run E85 when running higher boost levels(any boost levels really). But if needed, no big deal to run pump or other race gas after being setup for E85.

Agreed(other than a "Y" would be better).

Just do not run one line to the stock location, you need to modify the path and supply both lines(rear bank will run lean otherwise). There are different ways to do this, and this thread covers most of them. Rather than tapping, I'd weld on the desired size fittings instead. And I don't think you need to machine out the rails at these power levels.

On my personal car I have separate lines from the tank(-8, one from each pump), to custom rails, to a FPR, running E85.

You don't need to weld or tap anything. You can run individual lines to both rails without modifying the rails at all. Just utilize the stock fittings by running banjo to -6 adapters, and then remove the FPR and run an adapter there to -6. I've got the photo below of the banjo fitting I used cheap and easy.

Plenty of people have made 450whp and I'm sure even more safely using the stock NSX banjos going through 2 rails. Which would mean when you seperate out the rails into 2 individual rails then each rail would support 450whp individually as well. I think using the stock banjo's the rails would support at least 900whp, and would even venture 1000whp.

My setup is a little different. I am only running a single line and using the factory FPR. I am using a stock fuel pump and stock wiring at the tank and then running a surge tank setup in the engine bay. Didn't have to drop the tank which thank god I didn't my DW301 tank died within 1 day and had to change it to walbro 255. It hijacks the factory return and supply.

Here is how I would picture it using Dozer's picture above

**Elite** · 11-17-2012, 08:46

Originally Posted by hybrdthry911

You don't need to weld or tap anything. You can run individual lines to both rails without modifying the rails at all. Just utilize the stock fittings by running banjo to -6 adapters, and then remove the FPR and run an adapter there to -6. I've got the photo below of the banjo fitting I used cheap and easy.

Plenty of people have made 450whp and I'm sure even more safely using the stock NSX banjos going through 2 rails. Which would mean when you seperate out the rails into 2 individual rails then each rail would support 450whp individually as well. I think using the stock banjo's the rails would support at least 900whp, and would even venture 1000whp.

My setup is a little different. I am only running a single line and using the factory FPR. I am using a stock fuel pump and stock wiring at the tank and then running a surge tank setup in the engine bay. Didn't have to drop the tank which thank god I didn't my DW301 tank died within 1 day and had to change it to walbro 255, and didn't have to rewire the factory fuel pump. It hijacks the factory return and supply.

Here is how I would picture it using Dozer's picture above

Yeah, I know about those, I used them on Tim's/Jorligan's car years ago. I fed each line at the end from where the factory crossover line was, and returned from the factory feed spot, and the factory return location both(to an Aeromotive FPR etc).

On Sduffass/Stephen's car, I fed from two locations. I fed from the stock location and drilled then welded an aluminum bung on the top of the rear rail(left the crossover line in place), and then returned out the oem line.

There are many ways to create a functional fuel system, and most will work for most applications.