Race Gas / Pump Gas Dual Fuel System.

[GNBRETT]

Can anyone post detailed instructions and parts list to putting together a dual fuel system with race gas and pump gas?

I have an XFI with the thumb wheel for race/pump gas and was wondering what is the best way to build one of these units and what is needed.

Guys that have done it seem to swear by it and say it was the best HP investment they have made for a street car. Running race gas would be nice all the time but at $15 a gallon that's just not reasonable for most unless ur only a couple miles from where u need to go.

What are the pros and cons?

 

[Dynalow00]

I considered doing this a few years back. I wanted a Metco style spare tire well fuel cell for race gas, and then pump gas in the stock tank for daily duties. I purchased a GM dual tank switch for a pickup truck to handle the changeover. I wanted a Jeckyl/Hyde car. Flip the switch and the chip changes to race mode, the fuel supply valve switches over to race gas, and the nitrous bottle is armed and ready (to spray over the front of the intercooler...)
This was before Razor and his alky kits and before Turbo Tweak and his awesome chips. I abandoned the idea and decided to go the mainstream route- Get a good hotwired pump, 60# injectors, chip, and keep it simple. I still believe the Jeckyl/ Hyde car could be done (and very well may have been by others). I just decided to go an easier route.
I think I still have the fuel tank valve. You can have it free if you want it. -Steve

 

[corsair231]

Look for Turbo1dr on here. Has a yellow Malibu conversion. He has one of the slickest dual fuel systems I've ever seen. His uses two sets of injectors so the race gas is always ready. There is no purging the street gas from the lines and it is boost referenced so it automatically switches from one set to the other. He said the transition is seamless too.

 

[just plain john]

I agree, that'a the slickest system I've seen. Very well executed, and he gives a detailed breakdown on how he did it.

 

[Otto J]

A complete waste of time IMO. Race gas will take you a little farther than a well tuned dual nozzle alky on pump gas.
for as often as a street car built for alky use would be turned up to the point it needs race fuel your better off just pumping out the fuel and swapping it.

 

[Razor]

Yeah then you have the detractors say the alky system can fail.. Not that the secondary fuel system cant fail.

For a twin fuel system it need two feeds as well as two returns. I have seen liquid flow switches on boats to select between two different gas tanks. And they have 4 large ports manually or electrically activated.

Tom Shay up in Michigan use to make a switch pitch fuel system.. That would be another reference.. this was done back in the day pre-alky.

 

[jasjamz]

I believe Spot my 6 did it years back also. Not a dual injector system either. I looked into it but found it hard to find the valves to switch the feed line that would handle the fuel pressure we need at 28+ psi. After looking for one for a while I gave up on the idea.

Im sure Brett knows that alky sysytems are available, however this is not what his thread is asking for. Lets not turn this into another Alky vs Race gas (no offense Razor) thread....:wink:

 

[krom]

A guy here in Phoenix had one, he put the 2nd tank in the spare tire wheel well so it remained hidden. It was great, but I am not sure how it worked.

 

[GNBRETT]

Look for Turbo1dr on here. Has a yellow Malibu conversion. He has one of the slickest dual fuel systems I've ever seen. His uses two sets of injectors so the race gas is always ready. There is no purging the street gas from the lines and it is boost referenced so it automatically switches from one set to the other. He said the transition is seamless too.

Yea, I have seen his setup but it's a little complicated and requires another set of injectors to be fitted into ur intake.

I have a set of instructions that someone sent me a few years ago on putting a dual system together and it's very detailed.

I am just curious to know if others have done it differently and how.

 

[just plain john]

For those who might not have seen it http://www.turbobuick.com/forums/fabrication-no-solicitation/279383-sequential-dual-fuel-system.html. Very well thought out and executed.

 

[BOOSTBROTHER]

That is a very nice set up.


Look in this Mo HRM you will find a set-up like you are talking about it is even on a GN.

 

[GNBRETT]

That is a very nice set up.


Look in this Mo HRM you will find a set-up like you are talking about it is even on a GN.

what is HRM?

 

[soonergn]

what is HRM?

I believe that is Hot Rod magazine.

 

[GNBRETT]

Ok, thanx. Hot Rod. I will check it tomorrow then.

 

[SPOT MY 6]

I have a dual fuel system and LOVE it. It was very costly becuase I have two complete fuel systems from the fuel lines back (meaning, one -10 feed, one -6 return, one rail, and one set of injectors, but two pumps, two tanks, two filters, etc). The race system has a Metco spare tire cell, Weldon pre filter, and a Weldon 2015 pump. The street sytem consists of a double-pumper in the stock tank. I have to manually switch from one system to another which is done by opening the trunk, flipping one switch (to pick which pump to run), closing one shutoff valve and opening another. I chose to do it this way because my $11k motor and countless R&D hours is worth a heck of a lot more than 30 seconds of my time. The automatic systems were not reliable enough for me (a failing hobbs switch turning off the race fuel would knock the rods out of my 9 sec 109 instantly) and I did not want a dual rail setup. My setup was still expensive but has a quick ROI in my case because I mostly street race and drive to/from all races, and I like to cruise it a lot. No more wasting c or q16, flushing the 93 out of the tank to get as much pure race gas as possible, fiddling with two fuel jugs and all that crap that really pissed me off. Its probably my favorite thing on my car. It basically works like this:

Here is the feed side. Ill start with the pump gas system. Fuel pumps from the double pumper through a -10 one way Aeromotive check valve ($70/ea!) then goes to one port on a y fitting. The race fuel side works the same way, connecting to another port on the y fitting. Then all fuel tavels down one -10 feed through another filter mounted above the rear end (I think it's an Aeromotive filter, I'll have to check), then down to the rail. Pretty simple, right?

The return side: Start at the FPR outlet. All return fuel travels down one -6 line into the trunk and hits a -6 Y fitting. One port goes to a -6 fuel shut off valve, then to the stock tank's return port. The other y port also goes to a -6 fuel shut off valve, but to the Metco cell's return port. Pretty simple too, right?

So here's the drill:
- Turn off car
- Pop trunk
- If currently on 93, flip rocker switch to race pump
- Start car (to flush 93 out of lines with c16)
- After a few seconds, open race gas return shut off valve (so race fuel starts returning to cell)
- Shut pump gas return shut off valve.
- You are now in race fuel mode and it took just 30 seconds

If you need to switch back the order is a bit different to prevent 93 from entering the cell:
- Turn off car
- Pop trunk
- If currently on c16, open pump gas return shut off valve and close race gas return valve
- Flip rocker switch to pump gas
- You are now in pump fuel mode

I'll see if I can find my parts list and diagram and post em here. Oh and before anyone asks, I have two different tuneups (one for pump fuel and one for race) so I usually keep the race tuneup in and just stay under 0psi when going to a street race. If I know I'll just be cruising for the day I'll put the street tuneup in so I dont have to be so careful. I wish the BS3 had multiple tuneups on a switch like the XFI does so I wouldn't have to do this.

 

[salvageV6]

Jaguar has dual tank switchover solenoids.

As well as JC Whitney.

Multiple ports for fuel injection.

Just check the pressure ratings etc.

Dual lines only really need to be a few feet long.

 

[GNBRETT]

I have a dual fuel system and LOVE it. It was very costly becuase I have two complete fuel systems from the fuel lines back (meaning, one -10 feed, one -6 return, one rail, and one set of injectors, but two pumps, two tanks, two filters, etc). The race system has a Metco spare tire cell, Weldon pre filter, and a Weldon 2015 pump. The street sytem consists of a double-pumper in the stock tank. I have to manually switch from one system to another which is done by opening the trunk, flipping one switch (to pick which pump to run), closing one shutoff valve and opening another. I chose to do it this way because my $11k motor and countless R&D hours is worth a heck of a lot more than 30 seconds of my time. The automatic systems were not reliable enough for me (a failing hobbs switch turning off the race fuel would knock the rods out of my 9 sec 109 instantly) and I did not want a dual rail setup. My setup was still expensive but has a quick ROI in my case because I mostly street race and drive to/from all races, and I like to cruise it a lot. No more wasting c or q16, flushing the 93 out of the tank to get as much pure race gas as possible, fiddling with two fuel jugs and all that crap that really pissed me off. Its probably my favorite thing on my car. It basically works like this:

Here is the feed side. Ill start with the pump gas system. Fuel pumps from the double pumper through a -10 one way Aeromotive check valve ($70/ea!) then goes to one port on a y fitting. The race fuel side works the same way, connecting to another port on the y fitting. Then all fuel tavels down one -10 feed through another filter mounted above the rear end (I think it's an Aeromotive filter, I'll have to check), then down to the rail. Pretty simple, right?

The return side: Start at the FPR outlet. All return fuel travels down one -6 line into the trunk and hits a -6 Y fitting. One port goes to a -6 fuel shut off valve, then to the stock tank's return port. The other y port also goes to a -6 fuel shut off valve, but to the Metco cell's return port. Pretty simple too, right?

So here's the drill:
- Turn off car
- Pop trunk
- If currently on 93, flip rocker switch to race pump
- Start car (to flush 93 out of lines with c16)
- After a few seconds, open race gas return shut off valve (so race fuel starts returning to cell)
- Shut pump gas return shut off valve.
- You are now in race fuel mode and it took just 30 seconds

If you need to switch back the order is a bit different to prevent 93 from entering the cell:
- Turn off car
- Pop trunk
- If currently on c16, open pump gas return shut off valve and close race gas return valve
- Flip rocker switch to pump gas
- You are now in pump fuel mode

I'll see if I can find my parts list and diagram and post em here. Oh and before anyone asks, I have two different tuneups (one for pump fuel and one for race) so I usually keep the race tuneup in and just stay under 0psi when going to a street race. If I know I'll just be cruising for the day I'll put the street tuneup in so I dont have to be so careful. I wish the BS3 had multiple tuneups on a switch like the XFI does so I wouldn't have to do this.

Great write up. Thanx. Appreciate it. That would be great if you could list each part and a diagram.

 

[Turbo1dr]

What are the pros and cons?

Pro's: Best thing I've ever done. Always ready for action...not limited in the amount of boost you can reasonably run.
Con's: Labor intensive and Cost if you design it like mine.



The main fault I see in a dual fuel system without two sets of injectors is the race gas and the pump gas will ALWAYS be mixed and this will dilute the race fuel eventually if you use it often. The system I designed will never mix race gas and pump gas together so it never gets diluted. Its never turned on while cruising so there's no burning unnecessary race fuel when it's not needed. The total time the race fuel is on might be 9 seconds at a time if you have a 9 second car. By then, you could be doing 140+mph! This is the main reason I wanted a dual injector set-up. My design is completely automatic...ready anytime...all the time...under any conditions with minimal "on time" and it is a seamless transition.

There's no need to point fingers at it as being unreliable...it's just as realiable as ANY alcohol system out on the market. If anything on the alcohol system fails then you are going to be up siht creek just like a race/pump system. After all, the alcohol is not being considered as a "another" fuel system by many people and in fact it IS a second fuel system.

People put down dual fuel systems when it comes to reliability due to pressure switches. I've never had any luck with the screw-in hobbs pressure switches myself. Many years back when I had one on my in-tank double pumper, I could set it and then test it but it would never be activated at the exact setting it was suppose to be set at. The ones in the picture below have been very reliable and I've had ZERO PROBLEMS.. Plus they stay at the setting I have them adjusted on. They are fully adjustable from 2-24psi or 15-60psi which ever switch you want to buy. I've had zero problems since my dual fuel system went into service August 2006. It will even work with the stock computer if you have the same size injectors in each fuel rail.


Here is my drill:

Start car.
Put in gear.
Nail throttle

 

[Razor]

I think the fear is the fabrication involved in making the second rail, and making another fuel system(regulator,pump,cell,hoses,fittings,etc).

I personally dont like pressure switches of any kind due to dead band issues.. meaning it activates at lets say 8 psi, but doesnt shut off until its below 2 PSI. Every mechanical switch will have this issue. I'm suprissed you didnt go electronic for the switching. A simple VCS(voltage controlled switch) could be tied of the MAP sensor and activation/deactivation would be at the same boost.

I dont know about the BS3, the FAST XFI has an output you can set based on boost.. that would allow on/off based on that. Altho, it wont run 16 injectors like the bigstuff will.

The beauty of an alky kit is 2-4 hours latter.. your rocking and rolling.

 

[Turbo1dr]

The beauty of an alky kit is 2-4 hours latter.. your rocking and rolling.

I agree!

the FAST XFI has an output you can set based on boost.. that would allow on/off based on that.

I've already got" back-ups" if the pressure switches fail. Injector wiring. Fuel pump wiring.

Oh and before anyone asks, I have two different tuneups (one for pump fuel and one for race) so I usually keep the race tuneup in and just stay under 0psi when going to a street race. If I know I'll just be cruising for the day I'll put the street tuneup in so I dont have to be so careful. I wish the BS3 had multiple tuneups on a switch like the XFI does so I wouldn't have to do this.

You have to do a lot of switching things just to get you up and running on race fuel. I'm not knocking the way you do it but I prefer ease of operation myself. :smile: I have just one tune on my XFI. Up until my set boost level (around 12psi) where the 116 kicks in, I have everything set to 87 octane tune. Anything over that it's on a race tune. The spark table also reflects the differences in 87 to 116 octane.

This is what I have my VE table looking like in my XFI. I use two different size injectors....60lb for 87 octane and 84lb for 116. You can see in this VE table where it switches from 60lb to 84lb injectors or 87 to 116.