Taking the EFI plunge ... wish me luck!
 

Well, I bit the bullet and scrounged for some deals on an EFI setup. I wound up a with a refurbed Holley Sniper from the Holley store for $400 less than retail, an in-tank pump retrofit kit w. Walbro pump and baffled tray, a braided PTFE hose kit w. AN fittings and a Wix 33737 filter regulator w. return.

The plan is to mount the regulator where my current Holley red pump is currently located ( just ahead and below the tank) and use my existing 3/8" fuel line. The supply and return (short lines) will be plumbed w. PTFE as well as the supply line to the throttle body. I will also swap out my ProComp dual plane intake for a Torker II I bought a while back.

I am going to try to retain my old mechanical pump to carb hard line and picked up the compression to AN fittings to do this just to maintain a "stock-ish" appearance. I just have to come up with a bracket to secure the end of the hard line coming off one of the fuel pump block-off plate bolts. My tank and fuel lines are only a couple years old so I decided to retain them and do the retrofit rather than purchase a new tank.

I have seen them plumbed this way but something tells me I should locate the regulator closer to the throttle body using the high pressure on the long supply run and regulated pressure on the short run to the throttle body. I have 3/8" supply & 5/16" return hard lines in the stock location (both are new) and could just as easily mount the filter/regulator right on the frame rail and plumb to my supply and return.

For you guys that have done this type of install, which way did you go?

I mounted ours in font of the tank. That way there is just one feed line running up the car. This was for a multi port setup. Make sure your sniper can be dead headed if you go this route

Good luck with your project. My return regulator is close to the intake manifold. It works well. When I find the time/motivation/ and money I would like to go to a pwm dead head set up. Will you be controlling spark as well? Dual sync distributor or crank trigger wheel?

No, just basic throttle body w. HEI and MSD Box. No synch.

That should be pretty simple and trouble free. Pay attention to the wiring, especially grounding and you'll get what you expect from it.

I’ll be doing it along with you bro.

My terminator X kit just got here today after a long back order.

For what it’s worth I’m going to set mine up like the OEMs do with a fixed regulator near the tank.

I’m asking questions, here, wondering how other folks installs and usage have fared???
Typically the minimum pressure side is advised to be 1/2 shipped inch, with the return also being 1/2 inch.
The theory being that a too small return line can cause excessive pressure, not allowing easy return of unused gas to tank???

Just asking, wondering, hope it works out.

The LS filter I have comes with bracket so it looks like a simple mount. I have the 3/8" and 5/16" AN6 fittings to use the 3/8" PTFE hose between tank and regulator for the supply and return including a 180 for the return line back to the tank. I'll my existing 3/8" hardline to the engine compartment and just cap off the existing 5/16" return line as unused.

I already have my existing electric fuel pump wiring w. relay right in front of the tank to connect to the in-tank leads so that's all set. I wired the old electric pusher through a hidden toggle which will now serve as a fuel delivery interrupt anti-theft device.

The only thing I am concerned with is the lack of a flat surface on top of the tank to mount the pump inlet/outlet flange but the kit comes with a thick foam gasket to fill in the "ribs" on top of the tank where I cut the access hole so I am guessing it's a non-issue.

I looked real hard at a similar "complete kit" with an EFI ready tank that was only $120 more than what I spent for my parts but there were some trade-offs. The hose supplied with the tank was the plain CPE type rather than the braided/PTFE lined I bought, the pump and regulator were no-name parts (I have Walbro and Wix) and the AN6 fittings are of unknown quality. The kicker was the tank drop ships from the manufacturer and would not be available to ship until the end of October, so, no bueno.

slightly different but similar stuff here. You need ot make sure the Sniper will work dead heading the fuel. I did my multiport back in '09 (commander 950) but different set-up with different requirements DEAD HEAD on multiport is NOT a great idea so mounted my return regulator on END of fuel rail using the original feed line as a return. Made NEW 1/2 FEED line from the LS1 fuel pump bucket in the tank to the rails.

Given the sniper is a throttle body type unit dead head SHOULD be OK. The 1 advantage of mounting the return regulator UP FRONT is fuel circulation.

I know you asked about fuel but RFI/EMI is a real issue for many with the Sniper so attention to wiring is key. Keep the pink ECU trigger wire isolated. Some use a relay for this wire to avoid RFI/EMI issues. Use heavy ground cables - don't rely on ground straps. Us resistor spark plugs and for plug wires, many have had luck with the MSD Super Conductor sets. If you have a FB account you should look at the Holley Sniper Owner's and Tech group: https://www.facebook.com/groups/100847380485430

Do you need to use a vacuum referenced fuel regulator? My Proflo4 needed one.

The Sniper has a regulator built into the unit. You don’t need an external regulator.

Depends on which Sniper you use. The Stealth has no regulator and is purposely designed to be dead headed so you can keep the stock appearances under the hood. Some of the others they sell can be dead headed but they generally recommend full flow and regulating the return to minimize injector pulse issues.

Generally when you dead head them you'll need a pulse damper to calm down the fuel pressure pulsing which will skew the AFR a bit and make it's ability to learn a little erratic, also makes it easier to dial in and read the fuel pressure much more accurate.

They'll also tell you they really prefer the regulator to be as close to the unit as possible for more accurate results. Especially if you are dead heading it.

Another tip that a lot of the dealers and pro tuners recommend is a vacuum referenced fuel pressure regulator. It gives more accurate fueling at higher vacuum situations. I always had one but didn't hook up the vacuum at first. I found that it really settled down my fuel trims once the vacuum was operational.

There are going to be a lot of ways to make it better, many of them they don't bother to mention when selling the kit. But it will all make the EFI swap much more enjoyable in the long run.

Some great information here, all appreciated.

The Holley instructions say it is OK to deadhead the fuel supply and running it the way it was intended (with a return) is probably best. It really is just one more hose connection but that said is my existing 5/16" return line too small? A buddy of mine installs these all day long and says they do it all the time with no self-learning or fuel curve issues and typically installs the Corvette style filter/regulator in the recess of the frame rail under the car. I guess there's lots of way.

In a new development last night, a damaged box Holley Sniper tank pump and sending unit magically appeared at the Holley Store for $350 delivered. Holley says it is a damaged box only, contents same as new. It is a Buick GS stock number and only differs in the length of the filler neck. I figure it will be simple enough to saw my fill neck off and mount it on the Sniper tank since they all have separate tank and filler neck anyway and pocket the $300 difference. Having the pre-configured setup will speed things up.

As cheap as that was, I couldn't pass it up for ease of install and will return the other pump and pickup when it arrives. I hate to do that but you know how it goes. I wish I had a dollar for every time this kind of thing happens. I pull the trigger on what fits my budget and wham! a better deal magically appears that wasn't there the day before. In this case, I had to act on it.

Some great information here, all appreciated.

The Holley instructions say it is OK to deadhead the fuel supply but running it the way it was intended (with a return) is probably best. It really is just one more hose connection but that said is my existing 5/16" return line too small? A buddy of mine installs these all day long and says they do it all the time with no self-learning or fuel curve issues and typically install the Corvette style filter/regulator n the frame rail under the car in-line with the supply and return lines for GM just behind the front wheel. I guess there's lots of way.

In a new development last night, a damaged box Holley Sniper tank pump and sending unit magically appeared at the Holley Store for $350 delivered. Holley says it is damaged box only, contents same as new. It is a Buick GS stock number and only differs in the length of the filler neck. Given the price, I am willing to saw my fill neck off and mount it on the Sniper tank since they all have separate tank and filler neck anyway.

As cheap as that was, I couldn't pass it up for ease of install and will return the other pump and pickup when it arrives. I hate to do that but you know how it goes. I wish I had a dollar for every time this kind of thing happens. I pull the trigger on what fits my budget and wham! a better deal magically appears that wasn't there the day before. In this case, I had to act on it as it will simplify the install.

Duplicate posts all of a sudden?

The size of the return is really dictated by 2 things. How long the return is and how big the pump is you're using. The pump size is going to be determined by the HP you're trying to feed.

Most systems that are supplying a very mild engine can get away with a smallish pump and won't need a big return line. Keep in mind if the return is too small you won't be able to regulate the pressure down enough, especially with a good sized pump.

When you get up around 500 hp carburated you'll want a 255 LPH pump minimum. That number changes with EFI pressures. In those situations you might get away with a 3/8 return but I always just do the 1/2" feed and return when I reach this level. It then has the ability to increase the pump for more power later without the need to redo any of the lines. Basically making it a permanent system for any engine that you'll never have to revisit again. The price difference isn't really enough to warrant one way or the other.

You can do the corvette filter/regulator deal, I've done that myself on installs. It's mainly popular because of it's ease of install and it's initial cost is cheaper. It worked fine for me on very stock or very mild setups. If you start making HP there are better ways to do it.
When or if you plan to really get into tuning these things and talking to people like Chris at EFI System Pro, some of the improvements I mentioned above will start to make more sense. For most that just install these things at a bare minimum, never look at anything but the touch screen, and let the system do it's thing, and will never actually see or realize some of the smaller things I mentioned and it will probably run fine for what most everyone is doing.
It's when you really want to dive in with a laptop where you'll find fuel trims and learning and many other tables can be even better with more finite tuning, and having precise fuel pressure is a player in all of that since it's a multiplier in the fuel tables.
If you're not into that, then I'd put it out of mind, let the unit self tune and enjoy.

Don’t remember if it was in the install guide, but the Edelbrock reps on there forum say there fuel maps where designed to be used with one. I Used the Edelbrock regulator made for the Proflo4.

You'll get more accurate fueling with one.

I’m using the holley 59.5 psi filter/regulator. Same concept but a beefier package to the oem type pumps.

Lots of horror stories about the factory c5 type regulators getting overpowered by more powerful fuel pumps. I have a 400 lph pump.

That's why I mentioned they have only worked okay for me with stock or very mild setups, most likely because the pumps in those applications weren't all that big. I also run a 400 lph in my own, and I just swapped in a 450 lph in dad's car.

It's not overly difficult these days to make 500hp or more with most any brand engine with just bolt on parts. In which case I would not recommend the corvette style filter/regulator. It would be time to step up to a good size feed and return, with a good regulator, preferably close to the engine, and a big enough pump capable of supplying the HP being made.

In the end, what will F.I. give you over a good carb .

EVERYTHING, EVERYTIME!!!!...lol

My reason for going efi was the 041 cam in my 10.5:1 iron headed 400! and i LOVE q-jets. When it was a daily driver,,,,you would spend the first 5 minutes pat, pat, pat on the gas so it would stay running, then (due to the fine tuning required to run too much compression with iron heads) depending on if is "wet" outside as to how bad it ran. The EFI allowed ME to put enough in it when its cold that it would actually stay running.....AND not be loaded up when it its warm. I could also INFINITELY adjust the AFR to the cylinders a little wet (not pig RICH) while "cruising" at low throttle.

Something else for the OP.....most stuff has been mentioned; however, one other point to make about EFI is your charging system MUST BE AWESOME!! rock solid voltage is a MUST for efi to perform correctly. So if you have NOT upgraded to at least a cs130 or 144.....this would be the time.

Im using this guy https://www.efisystempro.com/fuel-sy...75-876-888-889

They want $40 for the mounting rings. Im trying to figure out a good way to do it cheaper. Right now I have rubber P clamps around the line on either end. But I dont like it long term.

If you're good with a carb and know the ins and outs, not all that much if you stick with the throttle body EFI's.

I'm still a carb guy at heart and decades of playing with them I've learned a lot. What a lot of people find funny is that our 2 daily drivers are still carb, one Holley and one Q-jet, and they do everything perfectly. I only have the EFI stuff on the cars we play with.

The throttle body EFI's are okay. It's nice to be able to go in and pick an AFR you want for a particular cell and fine tune different areas of throttle and rpm. It's more difficult to do that with a carb and gets time consuming but it's doable, just not as precise. Probably the best thing I like about EFI is the self tuning and it's ability to sense and adjust for elevation changes. That's what really sold me on the throttle body EFI. We deal with so much elevation change here that you really just have to find a happy spot with the carb and leave it. The EFI keeps that AFR pretty steady no matter where I'm at. Nice when we go to the track that's near sea level and most of our driving is a mile up. Other than that there really isn't a big difference over a carb.

The multi port fuel injection systems have more advantages over a throttle body unit. Better fuel shot right at the back of the valve is one. The ability to tune individual cylinders is another big one that I like.

It just depends on what you're looking for and what you're willing to dive into.

That's an interesting piece. Haven't seen that yet.

I use Chris at EFI System Pro for all the EFI stuff we have. Bought both Sniper units from him and all the add on goodies as well. He has treated me good and gave me discounts for buying multiple units at once. He's been a big help in the tuning aspect of things as well and has been excellent support. Way better than dealing with Holley directly.

On that filter regulator combo, I haven't found a cheap way to do this stuff, lol. On the regulators, I always use the 13301 Aeromotive regulator because it does 2 things I wanted. It's vacuum referenced and that comes in handy if you really get heavy into tuning the system, and it also has the ability to switch back and forth from carb pressure to EFI pressure with a swap of the spring. I've used it for years with a carb before the EFI switch so that part was easy.

The filter deal, I've struggled with options there for a while and eventually settled on this.....
https://www.amazon.com/RUSSELL-65013.../dp/B0014BDEGG

Not necessarily this particular one but it's this style. They open up and have a stainless mesh screen that can be cleaned and reused, and you can change the micron ratings by swapping the screen if you wish (finer micron for EFI) They are alcohol compatible and they flow enough to support 1000 hp, also come in -6 and -8 sizes and probably larger. Best part is they are only ~$25 and you never have to buy another filter again.

I've heard that before on the charging system deal but never experienced any issues myself. Both cars still have bone stock charging systems with external voltage regulators with stock output alternators, and they both have been flawless in that department for over a year now using the Holley Super Sniper Stealth units.
:noidea: But I'm guessing it has a lot to do with wiring, isolating everything properly and having good grounds.

Yeah, I actually found the system cheaper at a show but decided to use EFIsystsemspros because they have such a stellar service reputation.

I thought the filter/regulator was actually pretty fairly priced at 120 for the cast unit. Its the $40 for mounting brackets that I balk at.

I havent bought the hyperspark stuff yet to control timing. Chris told me that if the car runs well now, Holley actually recommends you get the EFI up and going with your current ignition setup. One less thing that can go wrong during initial startup. You dont have to remove the distributor, you know the timing is right etc. After you get the EFI going then you can swap in the spark control items.

I'd have to have it in my hands but I tend to think there are probably multiple ways one could come up with to mount it....???

That is exactly correct about the ignition side of things. I've done the exact same thing on both cars here. Got the EFI systems on both cars first. Both cars have rock solid MSD setups that have been flawless for over 20 years, with boxes etc.... that I just didn't want to mess with.

So I put the EFI systems on both cars, very straight forward install, and left the ignition systems alone.
The plan was to eventually convert them both over to control ignition with the EFI unit. The MSD's are capable as is by just locking out the distributor and swapping a few wires around so I don't necessarily have to buy anything on the ignition side to make it work. Funny thing is after over a year on both cars I haven't changed either one. They both run so well as is I'm just not sure at this point if I should, or will, change the ignition.

Hope you will update on your progress/results, what things worked for you and what did not. I started this same conversion in the early spring but got stalled and the hot summers here make working in the garage a total no-go. I plan to get back to it in a couple of months once the temps have backed off the triple digits and have my car ready for the pleasant winter temps here.

You really shouldn't use compression fittings on anything on a car. If this is something you really want you can use flare fittings instead. Just a suggestion...

This is a shot of the Vette filter mounted. As Frankie notes, compression fitting have no place in high pressure fuel lines. I used a flare tool to bubble the ends of the hardline and used high pressure clamps for lines under pressure. The vent lines get normal screw type clamps. Much cheaper than AN fittings!

The snap-lock elbows are Dorman units.

http://forums.maxperformanceinc.com/...1&d=1631057256

Or brake lines...They are not SAE approved for anything.

That's about what I had in mind. I have the nylon braided PTFE hose kit that came with all the AN6 fittings so I'll just use them. I've found it a pain to do flares on hard lines already on the car with limited space to work in. I made all my brake lines and flared them but In my experience with plumbing of all kinds, I don't have a problem using a compression fitting.

One large pool of real life experiences, if you have local car shows like I do, to visit, walk around, yak it up with others there and get their experiences.

Yes, the 340Lph and up pumps will just crush the filter media. The C5 setup is only recommended for the 255Lph pump application which is where I'm at. This is more that adequate for the HP level (Est 400-450Hp) I am at. I think anything more would be overkill or insurance depending on your mindset.

The kid who who is going to help do this install, his dad does these installs all the time for Midwest Musclecars in Lake Zurich, IL. He uses the Sniper or Tanks, Inc. unit with the 255Lph pump or the supplied inline pump on Sniper and Fitech converted BBC applications and LS swaps of 500+Hp with no issues. He only uses the larger capacity pumps and filters for multiple throttle body applications or high HP/race applications with higher capacity (800-1500 Hp) throttle bodies.

I got a tanks inc setup from a guy locally who had it in a turbo 67 camaro. So yeah the pump may be overkill, but it’s fine.

I installed my lines in the rear yesterday and removed my Q jet. Removed the old full return line. I’ll attack it harder over the weekend. Had to drop the tank partially to install the lines.

Word of advice for anyone doing an in tank pump. They are awesome. Totally the way to go, but install a trap door in the trunk to be able to reach the lines and service the pump if necessary. If I ever take it all the way out again I’ll do that. Wasn’t about to fire up the cutting wheel over a 3/4 full tank though.

That is a great idea.

A trap door would add convenience, but is it worth cutting a big hole in your car for the relatively infrequent need to service the pump? I don't find dropping the tank in an A-body to be particularly difficult or time-consuming.

Yeah, I though about that too. On mine I have to drop the exhaust. I saw this 10"x14" waterproof hatch, but I'm not sure I want to cut up my new trunk floor ... it sits 3/4" high so I would install it over the trunk mat and the cut neatly around the flange, hsind the mat as a gasket.

https://i.ebayimg.com/images/g/abEAA...uI/s-l1600.jpg

Ah, gotcha.

They exit through the rear valance panel. The flanges of the tank won't clear the tailpipes and the tank doesn't drop far enough to angle it out. The tailpipes have to be dropped down onto the rear axle housing for the tank to come out but because my system is fully welded, I have lower the entire system in one piece. I have to disconnect at the collectors, remove the mid-pipe and tailpipe hangers and lower the whole system, supporting the front while the tailpipes rest on the rear axle.

'If you look at the '71 from the side, you don't see the tailpipes like you do on earlier models that exit below the bumper. They are tucked up into the quarters.

Personal preference for sure. My trunk is already an aftermarket replacement and has tech screws from underneath holding in line clamps. So it wouldnt bother me at all.

I wouldnt call dropping the tank hard per say, but I still dislike doing it. You either have to drain it or deal with liquid sloshing about. I just dont like extra work. Having to drop the tank simply to be able to screw on an AN fitting? That bothers me. Which is my own personal mental block to be sure.

A method i utilize is a simple scab plate. Basically 1/8 pice of alum to make a picture frame (about 1" wide). Beat the aluminum to your floor shape then what you cut out goes right back in with a 1/2 "lip" inside the hole 1/2" lip to the floor. Then seal/ blind rivet the "frame" to the underside of the floor. Drill and tap, countersink a few holes...perfcetly flush and formed per it USED to be the floor!

Nice addition...but some cars it is very easy to access the fuel tank so...50/50. My 2nd gen F-body tank drop absolutely sux.

Tanks Inc sells a nice stainless trap door that I've used on several installs. It sits very flat to the floor, and once the trunk mat is over it, you can't see or even detect it.

I recommend the trap door for a lot of reasons. A big one is if you really enjoy driving your car long distances. The pumps rarely fail but if they do, it's usually at the most inconvenient time, like with a full tank of gas, or while you're out on the road somewhere.

I was doing an install and had a wiring issue. The clip at the pump pushed the wires out as the clip was snapped in. Didn't notice it. Had it all wrapped up with gas in the tank ready to purge the lines for trash before hooking it to the engine and the pump wouldn't run. Nice thing about the trap door is having that pump back out in 2 minutes, with gas in the tank, never spilling a drop. Found the issue and fixed it. Literally done in 5 minutes and I didn't even have to get under the car. That trap door paid for itself before I even had the car running, lol.

Keeping a spare pump in the car for a planned road trip, can literally be swapped in on the road side with a trap door if there were ever an issue, and could be done in 15-20 minutes. That's the big reason I do the trap doors.

Otherwise I wouldn't care if every time I needed at the pump I was at home on the lift with the transmission jack under the tank. I can drop it down in 15 minutes. But when am I ever conveniently at home with proper equipment when something happens.

It's kind of like having those particular speed parts on the car that you can only buy from a speed shop or online. When do any of those ever fail and leave you stuck right outside Summit Racing?? LOL

Dropping the tank Sucks big time, i have dropped mine 2 times since i Converted to efi, 1 time to modify the tank for a proper return-line.
2.nd time to throw the whole tank in my "shed" and buy an efi tank lol.
Now with all new efi tank i am on the werge of pulling it a 3.rd time! because of sender issues.
After a LOT of trial and error and even a brand new programmable fuel gauge from speedhut i found that the new sending unit that came with the efi tank has a partially defective rehostat.
If i fill the tank to the brim the gauge will show empty with an occational flash of the needle moving. If the car is going downhill it wil mostly show 0 when going uphill the gauge works fine.
and it works fine when i get to about 1/2 tank all the way down to 0. and i am not pulling this tank again :/