70 MONTE Posted July 26, 2019 Share Posted July 26, 2019 Hey guys, going to be installing a Sniper fuel injection unit. It comes with an external fuel pump. Looks like it needs a vented tank and my 70 is sealed. I understand I can use a vented cap but it will leak fuel as it sloshes around. Since I don’t have a return line either I was wondering if anyone knows of a sending unit that will fit the stock tank that has 3/8 out and return lines and also a vent line? Quote Link to comment Share on other sites More sharing options...
MC1of80 Posted July 26, 2019 Share Posted July 26, 2019 Depends on what you want to do. I know for a fact that a 71 tank has 3 ports for venting and a 71 sending unit has the 3/8 fuel line and a return line. Or you can use your sending unit in the 71 style tank and use one of the 3 ports for a return. Hope this helps. Quote Link to comment Share on other sites More sharing options...
Paul Bell Posted July 26, 2019 Share Posted July 26, 2019 Hey Ken, unless you’re installing a GM fuel module and PWM fuel pressure controller, which is non-return and the best but most expensive way, you should look into a fuel injection tank from Rick’s Tanks, Aeromotive or Tanks Inc. As a return style system runs the pump at full power & current all the time, it’s best to have it in the tank where it’ll stay cooler. It’ll also be quieter. And consider using PTFE lined hose vs. rubber fuel injection hose. As for venting, a “vented” fuel cap is a check valve, it lets air in but not out. Tanks Inc offers an inexpensive vent/rollover valve that needs to get hosed to any location above the fill spout. A small charcoal canister is prudent to reduce the possibility of fumes in your garage. These self contained fuel injection systems are great-and they’ll get better. But they need a proper fuel system. 1 Quote Link to comment Share on other sites More sharing options...
70 MONTE Posted July 26, 2019 Author Share Posted July 26, 2019 I was hoping to avoid buying a new tank, pump, sending unit $$ by using what I got. I guess I can just buy the check valve vent to get by. Quote Link to comment Share on other sites More sharing options...
MC1of80 Posted July 26, 2019 Share Posted July 26, 2019 Or just buy the 71-72 tank. Done. Quote Link to comment Share on other sites More sharing options...
Paul Bell Posted July 26, 2019 Share Posted July 26, 2019 I gotcha Ken. You can use any of the unused hose nipples on the tank as the return. Just keep in mind that you can't just put an external high pressure EFI pump on a hose to a stock style pickup that's in the tank. Any fuel level below about 3/4 full and that pickup will be uncovered on acceleration or cornering. Even uncovered for a moment and your pump sucks air and your pressure drops to zero and the engine will shut down. 1 Quote Link to comment Share on other sites More sharing options...
jft69z Posted July 26, 2019 Share Posted July 26, 2019 Hey Paul, Any opinions on the fuel tanks Holley offers for F.I. applications? I'll be going the FI route with mine and curious if you've heard good or bad. You addressed this awhile back, just wondering if your opinion has changed any. Quote Link to comment Share on other sites More sharing options...
Paul Bell Posted July 26, 2019 Share Posted July 26, 2019 If I had to chose an off the shelf EFI tank, I'd go with an Aeromotive over a Holley. I like their bucket & foam baffle design over the Holley Hydra-Mat, which has no bucket. For our cars, the Aeromotive Stealth II tank number 18102. It has a 200LPH pump good to 600 HP and it's just under $500.00. Quote Link to comment Share on other sites More sharing options...
jft69z Posted July 26, 2019 Share Posted July 26, 2019 Thanks Paul, I'll research that one. Planning to go with 1 of the Holley EFI units, not sure which one yet. Either Sniper or Terminator Stealth (which can also control the 4L85E trans if I get that version ECM. Saves having to buy and install 2 separate modules for eng. and trans). Still need to call them up and chat a bit to see what they recommend. Going to be a stock LS6 454 with no real plans to upgrade further, except maybe a cam in the future. Thanks again! 1 Quote Link to comment Share on other sites More sharing options...
jft69z Posted July 27, 2019 Share Posted July 27, 2019 Looks like the Holley EFI Sniper fuel tank is one & the same as offered by Tanks Inc. Probably a little cheaper to get the 'Tanks" version. Even the Holley instruction sheet kept referring to 'Tanks Inc.' part numbers for additional stuff, lol https://www.holley.com/products/fuel_systems/fuel_tanks/efi_conversion_fuel_tanks/parts/19-126 http://www.tanksinc.com/index.cfm/page/ptype=product/product_id=386/category_id=144/mode=prod/prd386.htm The Aeromotive assembly you listed appears to be a plug & play unit, fully assembled and ready to put in car. The Holley/Tanks Inc.version looks like you have to assemble/measure/adjust fuel sender and pump depths before putting in car. Close to the same price, but with much less drama. Quote Link to comment Share on other sites More sharing options...
Paul Bell Posted July 27, 2019 Share Posted July 27, 2019 The Holley/Tanks setup has a sump that holds fuel but it has a big hole to let fuel in-and out under acceleration. I think Holley either has a tank with their Hydra-Mat thing in it or they only offer it as a do it yourself kit. Either way, I say the Aeromotive design is better. Quote Link to comment Share on other sites More sharing options...
jft69z Posted July 27, 2019 Share Posted July 27, 2019 Yep, the hydromat deal looks like an add on to an existing tank, or a new stock replacement type tank they offer if yours is old and crappy. I'll be steering towards the Aeromotive tank. Thanks again, that's one decision I can now check off the list of things to get. Quote Link to comment Share on other sites More sharing options...
70 MONTE Posted July 27, 2019 Author Share Posted July 27, 2019 I see the Holley and Tanks inc (same tank) say the fuel pump has 1/4” inlet/outlets. The sniper manual says not to use less than 3/8” fuel lines. Is that going to be a problem? That is the setup Holley recommends for the sniper but they contradict themselves. Quote Link to comment Share on other sites More sharing options...
70 MONTE Posted July 27, 2019 Author Share Posted July 27, 2019 On the Aeromotive tank where does a vent hook up to? Quote Link to comment Share on other sites More sharing options...
Paul Bell Posted July 27, 2019 Share Posted July 27, 2019 It took a minute to find it but the Aeromotive send & return ports are -6 AN which is equal to 3/8" hose. Unless you're making big power, I doubt the 1/4" fittings on the Holley/Tanks setup will be a problem. I don't think a return style fuel system needs a tank vent but to be sure, ask them. Quote Link to comment Share on other sites More sharing options...
jft69z Posted July 27, 2019 Share Posted July 27, 2019 54 minutes ago, 70 MONTE said: I see the Holley and Tanks inc (same tank) say the fuel pump has 1/4” inlet/outlets. The sniper manual says not to use less than 3/8” fuel lines. Is that going to be a problem? That is the setup Holley recommends for the sniper but they contradict themselves. I think the I.D. of the 3/8 metal fuel line on the car now will be smaller than the I.D. of a 1/4" NPT fitting, so no worries there. Tubing and pipe are measured different. Quote Link to comment Share on other sites More sharing options...
Paul Bell Posted July 27, 2019 Share Posted July 27, 2019 10 hours ago, jft69z said: I think the I.D. of the 3/8 metal fuel line on the car now will be smaller than the I.D. of a 1/4" NPT fitting, so no worries there. Tubing and pipe are measured different. Pipe and hose sizing is of the internal diameter. BUT, a hose barb for 3/8" hose has a pass through size of less than 3/8", I'd bet down to 1/4". AN fittings and hose are different, if it's -6, which is the equivalent of 3/8", it's 3/8" through the hose and fittings. Quote Link to comment Share on other sites More sharing options...
jft69z Posted July 27, 2019 Share Posted July 27, 2019 I was at work last night when I replied, couldn't measure anything. The ID of 3/8 tube is .305" assuming a .035 wall thickness (that's what I have here). The 3/8 hose barb x 1/4" NPT fitting has an ID of .279" at the barb. I was thinking the 1/4 NPT part at the time which is roughly .330". Just for grins I measured a couple -6 AN fittings I have here, the ID is .293 on one & .280 on another. Quote Link to comment Share on other sites More sharing options...
Paul Bell Posted July 27, 2019 Share Posted July 27, 2019 Is that right. Quote Link to comment Share on other sites More sharing options...
jft69z Posted July 27, 2019 Share Posted July 27, 2019 It appears the AN -6 hose is equivalent to a 3/8 hose ID (that we already know), but the fittings are still going to be the bottleneck. Quote Link to comment Share on other sites More sharing options...
Paul Bell Posted July 27, 2019 Share Posted July 27, 2019 I ran AN-8 for my fuel system. The smallest part is the actual outlet nipple on the fuel pump itself. But as it's a non-return system, the flow is much less. Quote Link to comment Share on other sites More sharing options...
jft69z Posted July 27, 2019 Share Posted July 27, 2019 I actually did the same when I piped up my Camaro and old Monte, I ran 1/2" SS tubing front to back just to make sure there were no bottlenecks. In reality it was probably overkill, but helped me sleep better at night. Probably going to do the same with this Monte as I still have the 1/2" SS line I took off my old Monte in the attic . You think the old 3/8 fuel feed line will be good enough for a return line? I thought I read somewhere last night they said anything more than a few psi backpressure may cause a problem. They may have said don't use the vent lines as a return, probably because they are even smaller. Sleep deprived right now and can't remember a whole lot, lol Quote Link to comment Share on other sites More sharing options...
Paul Bell Posted July 27, 2019 Share Posted July 27, 2019 9 minutes ago, jft69z said: You think the old 3/8 fuel feed line will be good enough for a return line? Yeah, that'll do. 1 Quote Link to comment Share on other sites More sharing options...
70 MONTE Posted July 28, 2019 Author Share Posted July 28, 2019 Yeah they said not to use a vent for the return line. Sniper manual says 3/8 send and return. Quote Link to comment Share on other sites More sharing options...
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