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Attention more experienced Supra owners: Help me to put together a fuel system

2063 Views 31 Replies 8 Participants Last post by  outlaw star
Hey guys. I need a fuel system, but it's really hard to justify shelling out 23-2800 dollars for the premade kits. I'm wondering if you guys and list the components needed for a system that can support up 700 rwhp and cost somewhere between 1300 to 1500 dollars. If possible can you list prices and where to purchase each item. Thanks guys. 463.6 rwhp just isn't enough.


T-78, crispy critter clutch mod, RPS stage 3 sprung hub w/ lightened flywheel arriving this week.
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Me too! I really don't like the idea of paying someone $1k to round up a few parts and ship them to me:)
That is a step in the right direction for sure. The only thing I'm unsure of is where to find the braided -10 and -6 lines. I need to do some research on how much the price on all of this will be compared to the complete kits available but it can't be any more. One other thing is the fuel pump. The fuel pump seems to be external and I'm sure that would make a racket. Could I get a second stock fuel pump to provide addtional pressure and keep the noise down? If anyone knows how much all of these cost offhand, please post. It's appreciated.


You should talk to AdamGamz. He just hit 667hp with his T72 on his fuel system that he put together. Drop him an email. Check out his post about his run, he also goes a little into his fuel setup
Fuel systems aren't cheap

I've not ever done one for a Supra - yet - but I can tell you they aren't cheap for any EFI car. -6 and -10 lines can be gotten from Summit or Jeg's easily as can external pumps and regulators. Mustang for sale boards can be good sources for regulators, filters, and pumps if you don't mind an external one.

I'd question using -10 lines for a feed though, I did this on one car and it took two turns of the key to fill the line! That's a TON of volume. -8 would probably be fine but again I've NOT done one on a Supra yet so perhaps it's really needed. External pumps ARE noisy. I've heard Paxton, SX, Aeromotive, and others and if they aren't mounted in some sort of isolation form they will drive you out of the car as they use whatever panel they're attached to as a sounding board :( The car I've got now even had problems with the braided line pulsing and transferring noise to the car! Adel clamps help and should be used every foot or so to cut down on line movement.

Be sure you price out all of the fittings and whatnot - you may be surprisedto find that it comes close to the setups being advertised by others. This has been my experience with systems for other cars. The fuel rail for the Supra appears to be a bit expensive IMO and if\when I get to the point of needing one I may speak to a fabricator. Fuel rail material for most EFI setups is cheap by the foot so the price of the Supra units seems a bit out of line. Sites like Force-EFI can supply oddball parts as can Kinsler but Jeg's and Summit should supply most of what you'll probbaly need.

Oh, and if you source all the parts yourself chances are you'll end up with extra fittings :) I've done three systems now and have a whole box of leftovers - it just always seems to happen! Have fun and if you do manage to save a significant amount of money do us all a favor and documnt exactly what you had to buy so that the next guy with your question has someplace to go...
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Outlaw, go to for good prices on Braided lines and hose ends. As for secondary fuel pump I got the Walbro for about $120. You can search the net on Walbro and find some hits there.

My fuel system consists of a dual intank fuel pump going into a NOS Y distribution -8x-6X-6 into a -8 bulkhead out to -8 line into an inlie filter. Out of the filter, -8 line into another -8x-6x-6 Y distribution block. One end off the Y distribution to one end of the HKS fuel rail (-6) The other end off the Y goes to a -6x-6x-6 TEE. One end of the TEE goes to the other end of the rail(-6) the other end of the rail goes to the FPR with the stock return line.

I think this system works well for me. The total cost of the system was about ~$1600-1700. I hope this helps.

I have a diagram and parts list on my web site. I'm in the middle of putting the system in. Tank assembly is done, filter installed and stock rail/injectors getting ready to come out. I ended up with a few fittings left over myself. Looks like I could have gotten away with about 15 ft of line going to the front instead of 20. I'll be putting together write ups as I go.
Just one end?

Looks like you're putting fuel in one end and pulling it out the other - yes? With a rail as long as that one I'd be worrited that there would be issues with feeding the furthest injectors and problems with pulsing. Does the rail you're using only have to two holes for fittings? You're going through the stock filter on the return line too - why is that? Are you using the stock feed lne as a return?
Thanks guys. I'm taking in all of this. Kepp the great ideas coming.

I'm feeding one end just like the stock way. I haven't measured both rails but by just looking at them they look the same length. The new rail can't significantly longer than stock or it would be right up against the fire wall.

There have been supras running the fuel the same as I am for a few years now. The center return just recently became popular with cars going over 700rwhp. I plan to stay pretty far below that so I just didn't think the extra plumbing was necessary. Running dual pumps through -8 line should be plenty to keep the fuel rail filled. My SP rail does have a center return for anyone who wants to get it and plumb things that way.

Looking at the stock feed line, it's just under -6. Some sections near the differential appear a larger, but it's a small section. I was told that the feed line is larger than the return early on, so I decided to go with it when planning. The problem is connecting -6 returning to the stock feed at the fuel filter. The stock line has a flare type fitting into the filter. I don't know the size and trying to convert that to an AN size would be hard. However, on the side of the filter towards the front, it's a 12 by 1.25 mm. There is an adapter you can by this size with a -6 on the other. Very simple to put together. Now after saying all of that, when I had the fuel tank assembly apart, the feed and return tubing are the same size. To my eye, pretty much the all of the feed and return line front to back look the same with the exception of around the diff like I mentioned. So I don't think it would be a bad idea to use either.

If you use the stock return you'll have to hose clamp the braided line to it near the fuel filter. If you go with the feed, then you can use a fitting.
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what about doing this...

run two pumps and Y then together into a -8an, then run that up near the rail and run another Y and connect each of the ends to the rail, then with the middle port run a short line to the fpr then hook the stock return into the fpr.....this way each end of the rail would be fed with fuel? heres a pic to illistrate this.

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Grit - if it were my car that is how I would do it - I'm paranoid that way. I'm most familiar with Ford Mustang fuel systems, those rails only have 4 injectors per side but the wtwo rails are often linked together to form one long "chain". A VERY common worry on higher horsepower cars is that the last few cylinders in the "chain" won't get fueld correctly. By the time all of other injectors have had their sip of fuel in a cycle the fuel reaching the end injectors is presumed to be pretty iffy. You can put your hand on the rail and feel the puleses, on my car I had a gauge screwed right into the rail and the needle would jump around noticably. As a result many people take the added step of trying to feed the rails in more than one spot or connect all of the ends and have the return in the middle of one of the rails.

I'm honestly not sure if all of that is an improvement, perhaps putting multiple gauges in a test rail and watching for pulses would be the way to find out. Larger diameter rails with more volume are supposed to help too but seem awful pricey for the Supras. I've not ever handled a Supra injector so I don't know if it's got the same sort of ends found on Bosch style injectors - if it does than building a rail shouldn't be too hard for someone with machine tools. Several places sell the stock cheaply by the foot but the PITA factor is high :)

IF I get to the point of needing a fuel system I'll probably Y a pair of internal pumps, runa single -8 line up front, Y it to feed both ends of the rail (-6?), run a -6 return from the middle of the rail to an Aeromotive regulator (I like these), and then run a -6 to the tank in the bank skipping over the stock line entirely. I'd be able to return it to stock more easily having left the stock stuff comepletely out of the loop (shrug). The added braided and fittings would add cost for sure but the line costs aren't too bad compared to the fittings :rolleyes:For the return line I'd even consider using Earl's Super Stock hose. I've used it before in other apps and the low pressure return would be perfect for it. You just have to watch heat sources and abrasion is all.

I don't think any one way is better than another right now since I've not had to do this so don't think I'm being critical. This is an area I hope I don't have to get into with my Supra after it gets here. But knowing me it'll happen sooner than I think so ponderig it now is a good idea. (lol) Maybe I'll sit down and price this all up to see what it would cost....
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Brand new OEM fuel pump

I was going to build my own system, but was taking too long. Went with a Stage 2 kit from PHR. I have a brand new (never installed) OEM Turbo fuel pump. I'll sell it for $175 plus shipping.
Here's an interesting setup

From I'm not sure this is any better or worse than others but it does feed both ends of the rail. I'd be worried about fuel not getting to the backside of the rail past the regulator but I don't know for sure that that would be an issue or not. Food for thought anyway. Guess I kind of wonder why they didn't just T the feed and do the return from the middle of the rail, same number of parts I think...
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Earl's line

I was just thinking about what BLKMGK said, with a different twist.... The stock fuel line and return line are -6 correct? Why don't people replace these lines with braided lines? Is it mainly due to cost? Do the pre-made fuel systems utilize the stock lines at all? Or all lines are replaced with braided ones?

Earl's catalog puts a warning on every braided line stating that it does not guarantee the lines will work with all types of fuel addictives. The only line that will work is the teflon lined one, speed-flex. Aeroquip catalog does not give such warning. Should this be a concern? Do the pre-made fuel systems use teflon lined lines?

Also, the minimun bend radius for the teflon lines is 4" while the non-teflon lines requires something ~2.5". Can the Supra fuel system meet the 4" minimum bend radius requirement?


I pretty much take those warnings as a CYA kind of thing. Yeah, it's not going to react well to nitromethane or maybe pure alcohol either but I'm not too worried about pump gas or maybe race gas. Do the others even make Teflon lines in larger sizes? I've generally only seen them in sizes meant for brakes and clutch lines. I've always used Russel or Aeroquip for my lines and fittings. The heavier silver fittings have proven to be pretty tough!
I'm seriously considering aluminum tubing for most of my fuel system. It should be easier to mold to contours and takes up less space. As a bonus, that setup needs fewer hose fittings. I'll use aeroquip -6 line for the rest; you need some to handle engine movement and vibration.

BTW, I'm running a group buy on Walbro in-tank fuel pumps. I'll post to the appropriate forum once I receive approval. Email me for more info.
Be careful

Aluminum can work harden with vibration and stress. I'm also not sure how well it will withstand road debris at 40+PSI of pressure. check that ratings on the aluminum too - I'm not sure it was designed for EFI type pressures but I KNOW some who have done it. I guess I just don't see the braided line as being all that bad (shrug).
Re: Be careful

BLKMGK said:
Aluminum can work harden with vibration and stress. I'm also not sure how well it will withstand road debris at 40+PSI of pressure. check that ratings on the aluminum too - I'm not sure it was designed for EFI type pressures but I KNOW some who have done it. I guess I just don't see the braided line as being all that bad (shrug).
Thanks for the heads up. If I do this, I will use stainless braided lines between the fuel tank and the hard line and the hard line and the engine. Combined with secure mounting, that should minimize the vibration and stress. Still, I hadn't considered that "normal" vibration could fatigue the lines. Road debris is a big concern of mine; I don't know how much of a problem it really is. The aluminum tubes I was thinking of are rated to 1000's of psi -- you can use them for brake hard lines.

If you were going to use hard lines, what would you use?

I actually more than enough -6 aeroquip hose for a fuel system or 3. I'm looking for the right answers, and the fact that OEM's almost universally use hard lines tells me something...
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