Skeese’s E85 Fuel System for 750 RWHP Thread
 

Aaaaaaaallllllllrighty guys. I’ve recently made a deal on a semi-p motor and an EFR 9180 setup to go with it which I expect to see 30 PSI on E85, so I am going to need a LOT more fuel! Given this high horsepower level there can’t be any fueling mishaps so I want to do it right the first time. I won’t be getting my hands on the motor/turbo until December so I’ve got plenty of time to prep my car for the upcoming big power and given the cost of lines, fittings, pumps, filters, injectors, and rails I’ve decided this is going to be a measure 500 times and cut once kinda deal.

I want to build the fuel system to support 750 rwhp. I’ve seen several semi-p/9180 dyno sheets where this setup has been close to the 600 rwhp mark at 18 PSI so I feel this is a good number to use for mathematically sizing my fuel system components. I’ve spent a good amount of time reading various threads on here regarding sizing, but want to lay out my plan for comments and suggestions before I pull the big dollar trigger on all of this stuff.

At this point my goals for this system are
• Support 750 RWHP @ 30 PSI
• Keep the stock FD fuel tank
• Run a FlexFuel Sensor and retain the ability to use 93 octane fuel if required (for the purpose of limping it somewhere if I have to)
• Use all PTFE fuel line
• Have at minimum a 15% safety factor on max fuel flow
• No fuel components are to be located in the hatch
• Easy filter changing ability

So before we get started I have my first question. I ended up getting a great deal on 32’ of Aeroquip -6AN PTFE hose and 15’ of the matching -8AN hose and all along assumed I’d be using Aeroquip PTFE fittings. After some post-hose-purchase research I came to find out they only make their PTFE fittings in steel and they don’t offer any aluminum ones. I would personally prefer to stick with aluminum fittings, so my question is will Fragola fittings originally designed for use with the Fragola 6000 series PTFE hose work with the Aeroquip Teflon hose? I’ve read mixed things online about compatibility. If not, is there any other aluminum fitting options that would be better suited for this hose?

https://cimg2.ibsrv.net/gimg/www.rx7...d6bf4d4516.jpg

Aeroquip -6AN Hose:
• ID = .32” OD = .43”
• 4” Minimum Bend Radius
• Stainless Steel Wire-Braid Cover
• Teflon Inner Tube

Fragola 6000 Series -6AN PTFE Hose:
• ID = .312” OD = .505”
• 6.5” Minimum Bend Radius
• Includes clear plastic cover on top on the stainless braided line (I’m assuming this is where the extra .075” OD comes from).


I’ve been using Solidworks to map out the system and parts that are going to be required. While a hand drawn sketch would likely work, I’ve got the time and I enjoy the CAD. I started planning with the fuel tank sump, since that will be where the fuel flow starts. I found that summit racing carries the Competition Engineering fuel tank sump kit for $68 which has two ½” NPT ports. From here I’ll use set of ½” NPT to -8AN adapters to convert to the two -8AN PTFE AN hoses that are going to run to the pre-pump filters. I don’t remember exactly how I came across it, but I found that XRP makes a 120 micro strainer that will couple directly in line with the -8AN hose end and the Bosch 044 fuel pump’s M18X1.5 inlet. I emailed with XRP and confirmed that this little guy has a stainless steel filter, is rated for use with E85, are capable of 16.7 GPM each when clean, and have a 1 PSI pressure drop across the filter. Oh, and the kicker here is they are only $54 from ANplubming.com. Seems like a legit deal.

https://cimg6.ibsrv.net/gimg/www.rx7...dd0592e50a.jpg

My next question is about the check valve. Is a check valve needed? I've never seen anybody using one, or maybe I've just overlooked it. Is there any benefit to using one? I can see how it would serve to protect the pump, but again I don't know if it is really necessary.

https://cimg2.ibsrv.net/gimg/www.rx7...06bc88c14c.jpg

From here I am going to be extremely original and use a set of Bosch 044 fuel pumps. I’ll buy a mounting bracket or make my own and mount the pumps on the side of the tank. In my research about the XRP fuel filter I came cross this check valve adapter which they recommend be used so as to eliminate the need for a check valve later in the system, however I have never heard of a check being used. Is this necessary or is there any reason to buy them/not buy them? From the twin 044 discharge ports I’m thinking I’ll run them into a rail and then out into a -8AN line that will run to the engine bay.

https://cimg4.ibsrv.net/gimg/www.rx7...764b157a53.jpg


https://cimg7.ibsrv.net/gimg/www.rx7...66a1de1d27.jpg


https://cimg2.ibsrv.net/gimg/www.rx7...074c7bcf48.jpg


Any comments/suggestions/input is welcome! I'll once I get through the questions in this initial setup I'll post my engine bay modeling as well as the math (based mostly on the Howard Coleman threads on here). I'm not entirely sure how well the mathematically calculated injector and fuel pump flow requirements reflect the actual fueling needs of a 13B for XXX RWHP, but I've go the time to figure it out.

Cheers guys, enjoy the weekend!

-Skeese

750 rotary rwhp SAE E85

750 X 1.92 = 1440 CFM / 14.471 = 99.5 pounds per minute of air

the EFR 9180 makes just under 95.

at 30 PSI you will be in the 90 pound area.

figuring for 95 which is tops...

95 at 10.0 AFR is 9.5 pounds per minute of E85.

9.5/ 6.54 = 1.45 Gallons per minute = 5489 CC/Min

5489 X 1.35 (lag and duty) = 7410 X 1.35 (adj to E85) = 10,003 call it 10,000:)

10,000 Gross injector requirements for 750 E85 3 Bar static pressure 10.0 AFR

you probably already worked that out.

while i appreciate your setup and it will probably work fine i would go a different route as i don't like the rail as a joining item. Kenne Bell has done extensive fuel system research and states you lose 20 to 30 % flow by joining two pumps. (go to their excellent tech section).

not only do you need a lot of fuel but your fuel pumps will be going against 30 psi of boost pressure so you will be needing to look at pumps at the 73.5 pressure on the flow charts. most are headed south at that point.

since you are in the one percentile of power at 750 i suggest you look at Fuelab offerings. after you do that call Rob Scharfenberg Chiel Engineer and have a chat. if you don't do Fuelab i strongly suggest you run whatever pumps you decide on at 16V using a Kenne Bell Boost A Pump.

good luck,

Howard

I recommend searching "Radium Ultimate Fuel Pump test" as well as Fuel lab as HC mentioned

Radium has a well engineered spread of fuel pump mounting items and surge tanks. i note their fuel pump test ended up pretty much like my thread Fuel Pump Options... the Walbro E85 and Gas pumps leading the way in the popular price category.

Fuelab is a few clicks above both as to performance and well as cost, but when you are suiting up for 750 hp...

hopefully you can log Differential Fuel Pressure.

i have an idea, and feel free to shoot it down, as i have no idea how easy this would be to implement this in real life.

why not run 2 fuel systems? basis for the idea is Howard not liking that manifold linking the two pumps

use the factory lines, in tank pump setup etc, but only run it to the primary fuel rail.

then, for the second pump, it then runs though the sump, with a second set of lines etc to the secondary fuel rail.

the pro's are that each fuel system is pretty optimal for flow, and of course you can shut off the secondary side when its idling/cruising. cost shouldn't be too bad, as you use existing (reliable!) stuff for half of it.

the con of course is that its complicated, and you basically have 2x the failure points. space might be a problem too.

Hey Howard. I was hoping you would catch this thread.


I worked out these same numbers last week at work while going over your thread where you were using 600hp as an example. On the front end, I'll be using a set of ID1000's in the primary position and 4 ID2000's in a 4 port FFE rail.

ID1000's = 1015 CC/Min @ 43.5 PSI X 2 = 2030 CC/min
ID2000's = 2225 CC/Min @ 43.5 PSI X 4 = 8900 CC/min

2030+8900 = 10,930 CC/min > 10,000 CC/min by 8.5%. Not quite my target 15% but the cost of going from the ID1000's to the 1300's or 1700's is HIGH.

I'll have to look into that data about the conjoined pumps losing flow. I don't understand why that would be. I did read the fuel pump comparison article that radium engineering did and it was for this reason I was leaning towards the 044 pumps. While the fancy new walbro's flow a good bit more fuel at 43.5 PSI the fuel flow drops off quickly as the boost goes up. The 044 however appears to push damn new the same amount of fuel at 3 bar as it would at 5 bar (~73 PSI so what I would need at 30 PSI of boost).

https://cimg4.ibsrv.net/gimg/www.rx7...56857c6d32.jpg

This all being said I really don't want to add the boost a pump into the system. As a mechanical engineer I don't like the idea of driving a fuel pump beyond the electrical voltage it was intended to run at. I have to think this would cause extra wear on the pump and ultimately increase the potential for failure. I know there are cases time and time again where this has not happened, but I personally don't like that idea.

I will however be looking into the fuel lab components. Given simplicity is part of my goal it would be excellent to run a single large pump. I'll be giving Rob a call next week to get a better understanding of the way the prodigy fuel pump works with the electronic fuel pressure regulator. While the fuelab setup is expensive, so is buying a new set of 044's and tacking on two of everything needed to support them.

Thanks for the input

-Skeese

Interesting idea, but the overall complexity of it wouldn't be ideal. I'm trying to build as simple of a system as possible with as few failure points as possible. It would only take one failure and boom...goodbye really expensive motor and really expensive turbo.


Which leaves me wondering, does anybody have any input on the fittings? I just left a car meet and was talking to a v8 rx7 friend about it there who had a couple horror stories about some mismatched hoses/fittings. I would like to figure this out first and foremost so I can start the process of buying new stuff and selling my stuff if I have to.

-Skeese

I will be "sumping" my fuel tank, and will run the now internal Bosch 044, in an external setup once the fuel tank gets its sump. I would recommend full race sump "tank", as its only 1 inch (height) at its tallest part. That means that when added to your OEM tank, it wont sit as low, which helps with the fuel pump placement, as the fuel pumps should not sit (or mount) higher than the lowest point of the tank/sump port (that's what I've read anyways). Here's the link to ti the full race sump kit:

Fuel Sump Kit - Full-Race.com

Like you, I don't like the idea of a boosting the voltage to the pump, mainly because its one more thing that could fail, and I like the simpler is better approach (well sort of lol)

Not that I have any experience, or knowledge, but I've seen what racers use and what works for them, and I can tell you that Weldon and Magnafuel are two of the brands that I've noticed that racers use. I've browsed the Magnafuel site/external fuel pumps, and these ones have caught my attention:

ProStar EFI Series* |MagnaFuel

Now, if you do want to use the good old bosch 044 (which I might do too, since I already have on in the gas tank), I have concerns about overheating the pump if used externally.

have a read through the Kinsler catalog, they don't like sharp bends, and things like that, so your pump to fuel rail is right out. it should be a Y fitting.

Kinsler_Handbook_32

I can't tell you much about this, but there's a new pump in development that can handle ~670lph (11k+ CC/Min and EASILY handle your 10k CC/Min @ higher base fuel pressures.

So my solution would be 6 x ID1700s (2 on Primaries, 4 on Secondaries) and 55psi base pressure (1950 CC/Min). 30psi boost is only 85psi at the pump + losses (so let's say 90psi at the pump), in which it could still handle your flow requirements.

I don't mind if you copy my setup with fuel filtration, and with e85, water filtration is pretty important too.

The ID1700s are made for this. 1000s and 2000s are amazing injectors, but you're asking a lot from them with a fuel they aren't specifically designed for.

I read through and did not see it answered, but the check valves are there to keep pressure in the lines when the key is off. Factory fuel pumps have them built in to lessen cranking time. With that injector size, you do not want to be cranking from 0psi and building to 43psi. The check valve helps with all of that.

I do like the idea of the lower profile sump. I'll keep this in mind either way but it would be for sure the best option I end up going with the fuelab single pump setup.

I was thinking what Howard was saying that combining the flow of the two pumps was what caused the flow loss, not the bend. I only liked the idea of the rail as it seemed to me it would be less likely to leak.

ID doesn't seem to think E85 is an issue with ID1000/2000's.

Fuel Compatibility – Compatible with Methanol/Ethanol/All Known Hydrocarbon Fuels. - ID1000/2000 spec sheet listed on the ID page for each injector.

I recently pulled a set of ID2000's that I had been running E85 for over a year and they looked just fine. I'm sending them to ID for general inspection and servicing tomorrow so I'll let them be the judge.


THAT ALL BEING SAID, does anybody have an answer to the fitting/hose question??

-Skeese

The main thing I have read has been about the manufacture of the fittings themselves. Example, Earl's fittings are among the best on the market. I have read that they have larger internal passages than an eBay fitting.

As far as mixing the hose to the fittings, you have the option of buying a single fitting and cutting off a length and checking the fit and assembly. Really, the only way I know short of contacting the makers of the hose and fittings directly.

I'll call both Aeroquip and Fragola tomorrow, and Earl's as a backup to Fragola but I expect they will all just suggest I use their hose with their fittings. I don't want to test fit each as they are expensive and I think it either is or is not a good idea to mismatch them.

I'll also be calling Fuelab and ID. I want to have a plan by the end of this next week so I can start ordering.

-Skeese

Aeroquip also offers the fittings in stainless steel, if that's your thing.

They only offer a handful of fittings in stainless steel, most of which are the smaller -3 and -4AN sizes. Given what they want for these tiny stainless fittings I can only imagine if they did offer the -6 and -8AN ones I need, the complete order would be worth more than my car currently is.

https://cimg8.ibsrv.net/gimg/www.rx7...5ed8bb3827.jpg

I did the in tank '044 with no check valve and its a pain in the ass on a street car.

You have to flick the key over to on to prime the system back and forth once and then start the car to get it to start right away.

This isn't an issue with a basic race car where you flick the fuel pump "on" switch and the pump is then running and then you start the car.

But it is safer for wrecks/fires running the pump through the ECU so it only runs with the key in the "on" position and with engine rpms sensed by the ECU.

Check valve it!

Next time I do a fuel system (probably the FD) I want to just use the two stock fuel lines to the two rails (primary & 2ndary) both as feeds from dual '044s with the regulator back at the tank dumping right in (like a Corvette) so I don't have to run another return line.

Or use both stock lines with a pump each as feeds and use PWM for fuel pressure through the ECU if I get a bad ass ECU.

i want to run dual fuel systems with 87 octane in the primary tank and e85 in the spare tank. the ms3pro i have supports turning off the primarys at staging. so all i need is two fuel lines and two return lines. the spare tank i have is from an 04 m45, it was behind the read seat, so it would fit the hatch of the fc well. i've been thinking this over for a while.

FWIW, think two stock hard lines would be less failure prone than one PTFE line. Steel is sturdier than rubber/plastic and two lines would provide some redundancy. If one goes down, at least you have some fuel whereas with one line your SOL. You can also push more fuel in less physical space. Also, should be easy to mount another line next to the existing. The return line would probably need to be resized tho.

No experience, just an opinion

I'm currently using 3 different brands of PTFE Fittings on my Earls Speed Flex line and None of them are leaking. You can feel it when you assemble them. If it feels loose... The Stainless Fittings will get hot. If I could do it all again..the one and ONLY thing I would change would be to use all XRP fittings. I used 3 of them on my set up and I remember the feeling of "WTF...Thats it?...That Easy" when I assembled them compared to the other fittings. I built my set up with (6) I.D1300's... But We ran out of Inj on the Dyno at 8300 RPM (Trying to spin to 9kish). I'm actually selling my 1300's right now and going with (6) 1700's.

In reading back through this and looking at my calculations for the required flow I had some questions regarding your numbers and units? I'd just like to better understand where the numbers came from and the units involved so I can link each calculation together. I want to have all my numbers solid before I start calling fuel pump chief engineers.


-Skeese

750 rotary rwhp SAE E85

750 X 1.92 = 1440 CFM / 14.471 = 99.5 pounds per minute of air

What is the 1.92 number and how did you come to that.

A fair question.

1.92 is the amount of CFMs to make one rotary RWHP SAE. I picked it up around 14 years ago from someone and use it because it works. I assume it was empirically derived. As in many math tools we use there probably is some wiggle in it but it is an extremely helpful tool and has proved very accurate over the years.

the EFR 9180 makes just under 95.

at 30 PSI you will be in the 90 pound area.

figuring for 95 which is tops...

95 at 10.0 AFR is 9.5 pounds per minute of E85.

do you mean Gasoline here? You have the E85 1.35 factor later in the calculation.

You are correct raising a question here… the last word should have been “fuel.”

9.5/ 6.54 = 1.45 Gallons per minute = 5489 CC/Min


Where does the 6.54 number come from, is it simply a conversion factor?

I use 6.54 for E85 weight per gallon.

5489 X 1.35 (lag and duty) = 7410 X 1.35 (adj to E85) = 10,003 call it 10,000

In your fuel pumps 2014 thread you had lag at 13% and then duty at 85% leaving a 15% safety margin, where is the 1.35 number from?

1 = fuel before lag and duty
1 – 13% = .87 adjusts for lag (lag of course can be more or less so it is an est)
.87 X .85 = .74 adjusts for 85% duty
1/.74 = 1.35


Also here you have another 1.35 for the adjustment to E85. In your other fuel pumps 2014 thread you had stated "E85 has 82,293 per gallon V gas at 116,090 so multiply gas times 1.41 for E85"

82,293/116,090 = 1.41. Is this not to be the figure for the E85 adjustment?

The relationship between BTUs and power in the rotary is still a bit muddy and can be figured a number of ways. BTUs is certainly one way but empiricism generally rules as other factors come into play.

BTUs is 1.41 but 1.35 is used by many. I find my results closer to 1.35 but don’t have enough data to settle on a number. If it ends up closer to 1.35 my guess is something in the fuel is lowering the conversion of the BTUs to power. beyond my pay grade at that point but I am very interested in getting a solid rotary conversion number and should have it within a month.

10,000 Gross injector requirements for 750 E85 3 Bar static pressure 10.0 AFR

Thanks for clarifying the numbers Howard. It all makes sense to me now.

Sounds like a good gameplan. I was going to spout off and say you should make sure the pump is safe to run on a duty cycle, but I went ahead and saw that is exactly what the pump is designed to do. Since that is the case, I think it will be a far more modern style of fuel system than the usual return style system.

I know from experience that E85 doesn't like to be returned to the tank after getting heated up by hot fuel rails and an engine bay.

With a well controlled fuel pump, this won't be an issue.

The bigger issue I see is the use of a Y-block. Why? One more point of failure, one more pressure drop, etc. Just run them in series, not parallel.

This is something that I'll be using for my setup as well, to cut down on fuel pulsation with such large injectors:

https://www.radiumauto.com/Fuel-Puls...Kits-P759.aspx

-8AN XR, which can be tee'd off one of the rails.

While I do aim to keep things as simple as possible I want to split the lines in the bay and run parallel. It has been discussed many times on here and the general consensus was that unless you were trying to do something absolutely nuts with fuel, which I am, then you would be fine running in series.

I'll look into the fuel damper.

So I've made some moves and will now be moving on to the next part of the setup. I had initially posted on here that I was sold on the Fuelab setup, but after some additional thought I erased the post as I don't yet want to commit to anything while I'm still in the planning of the whole system.

That being said, I picked up a set of ID1300 injectors to serve as my primaries which combined with 4 ID2000 secondaries will give me 11,530 CC/min worth of injector which will be more than enough to cover my needs. I sent my set of ID2000's off to ID for general inspection and testing, and bought the full race fuel sump with the twin -10AN discharge fittings. Before I get into the rest of the system plan I need to figure out how exactly to best go about sumping the OEM tank. I searched on here, and norotors extensively and there is very little information about doing so in general. I've never done this before so bear with me.

What I really need to figure out now to kick it off:

Do i really need to have a radiator shop professionally clean it before having the sump welded on? Some people apparently just rinse it out with soap and water repetitively until no fuel scent remains.

Where is the best place on the tank to have a 11"L X 3.5"W X 1" Max depth sump welded onto the tank so as to take optimum advantage of the OEM in-tank baffling?

What should I do with the fuel vapor valves on the tank? Would it be worth retaining a line on the passenger side one and the charcoal canister and having it through the canister and then vent the outlet of the canister somewhere back there? I'm not really worried about the gas smell, but I would prefer it not extend from the garage into the house.

-Skeese

i often weld gas tanks. i fill them to the overflowing point and let the hose run for 20 mins. it gets the gas, and there fore fumes out.

So I've now completed the flushing, reflushing, and re-reflushing of the tank. I've let all the remaining moisture evaporate and the dried out the inside using compressed air so I'm fairly certain the tank is clean and ready for cutting and welding.

https://cimg8.ibsrv.net/gimg/www.rx7...b5342cc9e5.jpg

https://cimg0.ibsrv.net/gimg/www.rx7...66362f7ce6.jpg

https://cimg0.ibsrv.net/gimg/www.rx7...4174657da9.jpg

I'm thinking that it may be worth retaining the fuel vapor valves on top of the tank and simply running lines from each into a tee and then having it vend somewhere in the back?

I'll be getting the fuel sump in today so I'll mark off the area that is going to be cut and welded and begin removing the tanks coating in that area. Any suggestions on how to best remove the coating? I was thinking die grinder with a steel brush wheel.

-Skeese

Either that, or do it chemically with Acetone/Paint Remover spray first, wipe off, then lightly sand/wire brush to a clean welding surface.

I would HIGHLY suggest taking it to a radiator shop once you have the sump welded in and requesting they do 4-5x layers of RED-KOTE for your e85 compatible seal. That's what I found is needed for my 1st Gen tank.

I personally tried acetone on my tank. Didn't freaking touch it. I had to bear down with a wire wheel attachment on my grinder. Wear a respirator. It gets messy.

I've got a friend of mine who's cousin runs a paint shop and he has everything needed to do the sealing. I'll check out the red-kote. I assumed the POR-15 was compatible with E85, but didn't think to check.

Thanks man. Noted. I'll be starting on that part this weekend and will be sure to grab a respirator from work tomorrow before I leave!

Will post fitup pics with the sump tomorrow, I just got the Fedex notification that it is at my house.

-Skeese

Alright, so I got the full race sump in. I'm impressed with the quality, but wasn't doubting it would be awesome for what it cost.

That being said, I need to figure out where on my tank it it would be best to weld it on so as to utilize the oem baffling the best I can.

Option A being in the center of the tank centered between the support straps. This would put it right on one of the 'lumps' if you will but would be clear of the oem rubber baffle thing that the fuel pump hanger and return line discharged into.

https://cimg8.ibsrv.net/gimg/www.rx7...60e998a164.jpg

Option B being to weld it to the flat part of the tank which falls directly under the oem rubber baffling where the return line would discharge. From welding perspective this seems like it would be easier, however I would have to drill holes through the orange fuel container cell thing which would get messy, or I could remove it entirely.

https://cimg3.ibsrv.net/gimg/www.rx7...c9a2a56197.jpg

Lastly I was rethinking the fuel vapor valves on top of the tank. I was thinking about maybe having a flange made to replace the valves and then installing a bulkhead fitting into each. I would then split my return line once it reached the tank externally and run a return to each bulkhead port. I could then angle the discharge of each on the inside to send returning fuel any which way I wanted, on both sides of the tank which would in theory reduce the affects of fuel slosh since return fuel would be incoming on both sides of the tank. I'd have to find some other way to vent the tank, but that can't be too hard.

I really first need some input on the sumps location as I want to start grinding off the coating and drilling holes tomorrow. Let me know what you guys think of the split return. It seems like a killer idea to me, but haven't seen anybody else do so which leads me to think there may be some problem with it I'm totally missing.

-Skeese

Might want to pump your brakes on using the vapor valve ports as fuel returns. That would induce quite a bit of aeration of the fuel and also get rid of a vent port for the tank. The tank does need to breathe when the engine is off. That's why the charcoal canister is there. To capture hydrocarbons and keep them out of the atmosphere. It also allows expansion and contraction.

I recently replaced a fuel tank on a car that collapsed under vacuum from a clogged canister. Eliminating the vapor lines would effectively do the same thing. The car was hot when it was parked. The fuel cooled and sucked the tank down and destroyed it.


Just google image search "fuel tank collapse". Many people have had their older cars fuel tanks crumple inward due to using the wrong fuel cap. Old cars didn't use charcoal canisters (early 70s and prior) but they did use vented caps. A vented cap, may or may not prevent this on the FD tank, but I would not personally take that risk. I personally think it's pointless to eliminate the canister. The primary emission from any car, excluding electrics, is hydrocarbons from fuel. That raw fuel vapor is dangerous and must be dealt with; enter the charcoal canister.

Are you thinking the additional aeration of the fuel would come from it dumping openly from the top of the tank? It would be extremely easy to use a AN to tube fitting to have the fuel pass through the flange and dump the fuel back into bottom of the tank on either side of the sump

I can find a way to vent the tank outside of these ports. From what I gather the purpose of the charcoal canister is to keep the car from putting out fuel odors due to fluctuations in tank pressure. I currently still have the charcoal canister in place but have been debating removing it as I'm not overly concerned about it smelling, if I accomplish 750, it will be a racecar.

If I were to retain the valves, tee them together with some line, and have the line just open to the atmosphere somewhere near the rear axle would that not serve the purpose of venting the tank? There has to be some sort of filter/vent/canister that is smaller and lighter than the OEM charcoal canister. that hunker is huge.

More importantly...

Does anybody have anything on the placement of the sump? I want to be ready to start making moves on that part tomorrow.

-Skeese

That's a better plan, but a 1/2' dump in the usual location with a tube to the sump would probably be sufficient.


Not fuel odor. Raw hydrocarbon, fuel vapor. Fuel vapor is still harmful. It's not about smell, it's about pollution. I know I sound like a dirty hippie here, especially since I have an RX7, but I prefer to keep the vapor where it belongs. In the tank.

[/quote]
I currently still have the charcoal canister in place but have been debating removing it as I'm not overly concerned about it smelling, if I accomplish 750, it will be a racecar.

If I were to retain the valves, tee them together with some line, and have the line just open to the atmosphere somewhere near the rear axle would that not serve the purpose of venting the tank? There has to be some sort of filter/vent/canister that is smaller and lighter than the OEM charcoal canister. that hunker is huge.

[/quote]

Yes, you can tee them together. There is a smaller canister available. Get an FC one. Its about the size of a coffee can. Not too big and easy to mount. I'm sure you can get one from a guy parting his car out. Get the bracket too.




uuuhhhhhh middle?:scratch:

Someone else who builds tanks should reply, but most drag racers mount them dead center in the middle. Between two existing baffles should be preferable.

I say most, because when I'm at Pacific Raceways, all tanks seem to be sumped in the middle.

Cut open the entire underside and drop in between the factory baffles as planned, wherever they may be. :D :egrin:

Forgot what type of fuel you're going to be using. But What I don't like about Sumps is the fact that it'll be the low spot in the tank. Meaning that everything that passes by, that sinks,...will get stuck and trapped down in there. And I don't know if you've ever had to clean out an OEM FD fuel tank before...but It's an absolute Pain in the ass... and Nearly Impossible to get to parts of it without rigging up some Makeshift scrubby tool.

I agree with you on that it isn't ideal that the sump is the low part of the tank, however I still believe it is my best solution. The downside of the swirl pot setup is that I would have to mount it inside the trunk of the car and as this will still primarily be an on-the-street car and I won't have a divider between the trunk and the cabin I don't want to do that. The only other option being a surge tank mounted under the trunk somewhere but these guys are all extremely expensive. In a perfect world I'd do that, but I can't justify tacking on an additional $700 before additional lines and fittings it would require.

I don't want to go with the in tank setup due to the fuel starvation issues that arise when the car is under half a tank, and given that it is extremely difficult to fit dual 044's in the OEM tank as it is, I can' only imagine doing so with some sort of additional custom made fuel collector in there would be a nightmare.

I'm pretty crafty when it comes to gizmo's and home made gadgets though, I'll start thinking on what I can do to build this makeshift scrubby thing you speak of!

-Skeese

The good surge tanks are internal, like on my build (I believe Winfield does them for FD's now too! Coachman Performance IST.) However, it is a non-pressure pump (lift only) and even running the Walbro 416 (e85 pump), it wouldn't be able to keep up. I'm still wondering why you haven't decided on two of these, since e85 is your primary fuel and Bosch 044 claims no more than 10% ethanol for extended periods.

If you were setting the car up for road course, an IST + two EXTERNAL fuel pumps would be the way to go. You'd have fuel capacity of 1.5L minus the pump, which is A LONG sweeper's worth, at least. Zero fuel starvation sounds good to me!

I'm sure I'm not the only person who thinks it's ok to run E85 through Bosch 044's and ID 1000's/2000's.

I haven't decided on two of those because their flow rate drops off sharply under heavy pressure. While the flow rate drop wouldn't cause it to flow less that a pair of the 044's it suggests to me the pump is struggling. I would prefer to use pumps with a less dynamic flow vs pressure curve. Solid. Pushes damn near the same fuel at higher pressures. No dynamic change.

I'm old school in a mechanical sense. I believe if it isn't broken, don't fix it. 044's are battle tested and proven, even on e85.

I'm not trying to over complicate things.

E85 is less lubricatory than gasoline, so you can expect fuel pumps to wear out more quickly. it would be a good idea to have some kind of fuel pressure info, either a gauge or an ecu input, so you can change the filter(s) when it drops, and or the pump.

also maybe lends credence to a dual speed fuel pump, or something along those lines, but simplicity might be better there

possible that whatever premix you're running makes the fuel pump/E85 thing a moot point.

Boost-A-Pump or Weldon Fuel Pump controller (ideally something constantly variable off of MAP pressure) could be a nice addition to keeping the fuel temps down and car streetably quiet.

I was thinking the 2-stroke premix would help with the pumping "dryness" issues as well. Interested to see what comes of this.

I am going on 4 years using 2-ID1000s and 4-ID2000s with 2-044's in an external surge tank and 1-044 as a lift pump. Car has never had anything but E85 in it and has sat extended periods of time when it was to hot to drive. I have had no issues what so ever so far but I do live in a very dry climate.

I'd be more impressed with your battery/alternator set up that's able to keep all that happy 👌👍

I have that covered for whoever needs it. 270A Alternator & Dual PC950 Batteries. :egrin:

On my build thread.

Well...I have been through a couple alternators. Current 180amp and Odyssey battery seem to be doing okay:blush:

I'll be running a fuel pressure sensor to the ECU and a gauge. Plan is to set up multiple fuel pressure fail-safes in the ECU the first being such that if the pumps are flowing less than the set base fuel pressure at idle or in any non-boost situation a warming light is triggered essentially letting me know that the filters may need cleaned. The second being that if the fuel pressure drops below X pressure while above X boost the ECU will cut the ignition while the fuel keep flowing. Between the two I should have a pretty good handle on monitoring the pressure.

I have a Boost-A-Pump at my disposal should I choose to use it, but I'm going to first just ensure I wire the pumps correctly with high quality wires and relays sized to meet their needs. If I end up with a fuel pressure drop issue with this setup I'll consider the Boost-A-Pump but I want to try the simple route that doesn't drive the pumps past their intended design first.

Good to know. I've seen multiple builds where people run 044's with E85 without issue. I'm not looking for a pump to last 10 years, I'm looking for one that will weekend warrior it when I ask it to and I believe with proper fuel filtration, monitoring, and maintenance I'll be well aware of when the filters need cleaned or the pumps replaced.

IN OTHER NEWS

I spent some time with the die grinder and a steel wire attachment and cleaned out the section on the tank where the sump would be going. It really wasn't bad grinding it off with the die grinder and steel brush. All in all I think I had about 40 minutes in it including multiple beer fridge runs while my crappy air compressor built back up pressure.

https://cimg9.ibsrv.net/gimg/www.rx7...fb8fdfe938.jpg

https://cimg3.ibsrv.net/gimg/www.rx7...a84e9522c6.jpg

https://cimg5.ibsrv.net/gimg/www.rx7...ba6b85a455.jpg

I dropped it off for welding and cleanup with D3 Performance Engineering to have the holes drilled and the sump welded yesterday and will be picking it back up this afternoon. They have a reputation here in Houston for being the absolute best automotive fabrication shop in town, so we shall see when I get my tank back. Picture update to come tonight. They gave me hell about the rotary thing when I told them what I was building, but I'm beyond caring about that at this point. It's my car, I like it, and I love being the oddball. Seriously...what is more hooligan oddball style than rolling in a completely stock body FD with a semi-peripheral port motor and huge turbo. Nothing. My kinda weird.

I got a spare "dead" 044 from a friend of mine to use for mock up purposes on the side of my tank. This was the first time I've ever held one and was surprised by the size, weight, and feel of the pump. When holding one, it is clear that it is a serious piece of hardware.

https://cimg4.ibsrv.net/gimg/www.rx7...5581ffb226.jpg

I've ordered a dual 044 mount that I think will best suit my mounting ideas. I'll be reinstalling the tank and mocking up the pump mount on the side of the tank positioned based on the pump/filter/checkvalve/fitting dimensions that I've modeled in cad.

Can somebody provide the link to the study that shows how combining the flow of two pumps into one line causes a 30% reduction in flow? I searched online everywhere and couldn't seem to find anything to support that.

My current plan is to run twin -10AN suction lines to the pumps then twin -8AN lines out of the checkvalve (fitted directly onto the discharge of each pump) and then Y them together and run one line to the front. I'm unsure of whether it would be ideal to Y them together into an -8AN feed line to run to the post pump filter and then into the engine bay or a -10AN feed line.

Lastly, where would be the ideal placement for the post pump fuel filter in relation to the pumps being mounted on the side of the oem tank. Closer to the pumps? Closer to the engine bay? Right in the middle? I'm not sure.

Sorry for the novel. Fuel sump welded pics tonight. Thanks for sticking with me here.

-Skeese

I currently have the odyssey PC680 but am planning to get a bigger battery and relocate it to the rear bin before the motor gets here while also sending my alternator off to IRP for their 90 to 140 amp alternator upgrade. Seems legit to me and the price isn't bad.

-Skeese