Broncobowsher
Total hack
- Joined
- Jun 4, 2002
- Messages
- 37,073
Started the install of the Holley Sniper yesterday evening. About 2 hours in and better than halfway there. It is a drop on replacement for an existing aftermarket Edelbrock carb. In full disclosure this happens to be on a 460 in a 2WD '77 F250. But the details will be the same as a Bronco. The 460 architecture is pretty much an oversized small block. A duraspark is about the same as any other. So lessons learned here will carry over.
I have already done some pre install work. Both stock tanks (this will be a 2-tank EFI install) are stock. Lack any baffling. I added a new fuel pickup using a Holley hydramat. The stock pickup sock had already fallen off or fell apart. They will now be the fuel return. In the Hydramat instructions they mention returning the fuel right at the pickup. Do not return it at the top of the tank and allow it to waterfall. I had waterfalled the return in the past. Aerating the fuel. I used a 4-port accumulator to degas the fuel in the past. No accumulator this time. Also looking at stock EFI setups, the return is at the bottom. So both tanks are plumbed for a new pickup, and I drove around with the carb hooked to them so I know they work. When the hydramat goes dry, you are out of gas. Bonus, since it does suck the tank dry I get an extra 2 gallons out of a tank. The rest of the fuel system is experimental. Each tank has its own pump. Both outputs are tied together and feed a single filter. The theory is whichever fuel pump is running, is the delivery pump. The one not running is blocking fuel with the check valve. I remember working on an early 90's F150 that had a similar fuel system. Both tanks Tee'd together with no valve. The return I never figured out. But I figured mine. The entire original fuel system is now the return right down to the fuel selector valve. The selector valve in my case is a simple electric solenoid. Add a standard 5-pin relay. Coil attached to the fuel selector solenoid. Common to the fuel pump wire off the Sniper, Normally closed to the main tank pump, normally open to the aux tank pump. Failure modes, gas goes into the wrong tank. When I am done we will see how good this works.
Also part of the prep was I have an O2 bung welded to the exhaust down pipe. I have been driving it with a generic narrow band O2 installed and spliced into a free coupon Harbor Freight multi-meter. Idle with the carb is a little lean or a little rich depending on what mood it is in. The normal driving is generally a little rich except for fast cruising which was a little lean. A bit difficult to run that spot as it was driving faster than I liked. It was the spot just before you got into the power enrichment or maybe the secondaries. So I know I am starting with a fairly well tuned carb as a reference point. I can play with the choke and watch the meter and know right when I get into the choke as it goes from a rough idle lean cold miss to slightly rich and smooth.
So that is the prep I already did. For reference I have ran a Holley Projection 4Di about 20 years ago. That was an advanced system with an O2 sensor back in the day. Totally out of date today. I am looking forward to this new self learning EFI
Unboxing the EFI it looks good. Went for the classic gold which will mostly hide under the (slightly modified) stock air cleaner. The injectors are in the base, not on top like the old Projection/GM TBI. There is a ring of tiny holes just above the throttle blades for the fuel. No other obstructions, just 4 good sized throttle blades. Although I did notice that the secondary side doesn't open 100%. It opens almost all the way, I am not going to worry about this. The harness looks like good quality. Some over braid was provided but I went on Amazon and picked up some more so I could cover all of the exposed wires. Plenty of wire length on everything, in fact you need to plan a little on the routing to use up the extra wire length. Way better than too short. There are 3 capped vacuum ports on the back. One for ported vacuum (it's weird that it is on the secondary side of the throttle body but with 1:1 linkage it should work). A small manifold vacuum, in my case it will run the vacuum controlled heater valves. And a large vacuum port Holley calls "brake booster" but I will do PCV. It is branched equally to both sides. There is a pipe plugged vacuum port at the front of the throttle body. I would leave that alone. The computer is at the front of the throttle body along with the MAP sensor. It senses the front cavity that the vacuum port shares. I want to make sure this reads true manifold vacuum, not something less as you might get if there is air entering this port. Why is the port there? The Super Sniper kit supports boost, there are ways of blocking the MAP from reading internally and make it read external manifold vacuum/boost. So leave that from vacuum port plugged.
The plan:
I guess I better get to this. I will be doing the install in stages. In fact it is even a recommendation in the Holley instructions. Round one is simply get the EFI running and leave the stock Duraspark untouched (other than pulling switched power and tach signal). Do the basic carb swap approach.
Round 2 will be conversion to computer controlled timing. I am going to make the Duraspark distributor work. I don't see any reason I can't. I know Holley wants you to use there fancy expensive distributor options to make this work. They want an indexable rotor so the spark is on time. I got a couple simple tricks in mind. Stay tuned.
Round 3 is the progressive linkage upgrade. I picked up the simple kit from https://www.efisystempro.com/sniper/sniper-efi-system-components/sniper-efi-progressive-linkage-kit. There is a reason this is #3 instead of #2 in changes. The ported vacuum is on the secondary side of the throttle body. With the Holley supplied 1:1 linkage this works just fine. But with a progressive linkage, there would never be any vacuum advance. Going computer timing first means this isn't a problem. As far as the progressive linkage only opening the secondaries 97% with the simple linkage, that is about what they open to now with the Holley linkage straight out of the box. And it's not like the 250-300HP will be hindered at all by slightly less than 800 CFM the throttle body is rated for.
Kickdown is going to be a problem. When I was at SEMA looking these kits over and asking questions they stated that the old style Ford kickdown doesn't work on the Sniper. People have adapted it to work. I have a kit off the Edelbrock that I really don't like because it sticks out so far but I am going to start with that and see if it will work. Thought about a Lokar cable kickdown. And I am thinking of going electronic and using a diesel shut down solenoid controlled by an Arduino. In short there are options, but if you have a C4 or C6 with the original kickdown rod be warned that there will be challenges ahead for you. And if you have an AOD, you also need to think about the throttle valve won't be paired to the throttle correctly. With the larger throttle body and 1:1 linkage on the secondaries part throttle will be making a lot more engine torque then the TV will be showing. You will probably want to start with the progressive linkage kit so the trans will live through light throttle driving. Hopefully if you are doing a Sniper you won't be dealing with an AOD and will have something a lot newer like a 4R70W.
Well that's it for now. I got it opened, planned, and bolted to the engine. Fuel supply is hooked up. For the low pressure rubber hose I am running Shields barrier marine rubber fuel hose. The pressure side is Earl's vapor guard EFI hose. Not cheap stuff, but they have an inner layer to protect the hose from the fuel. To get the hose to slip over the fitting I wet the connection with a drop of 2-stroke oil (it is designed to mix with fuel and burn in an engine). I am stopped right now because I am missing parts. The return is on hold because I forgot to order the replacement roll of 3/8" tubing. I have the flaring tool to do AN-6 and the feed and return on the EFI are AN-6 fittings. I am going to try to make a one piece return line from the EFI down to the old fuel pump. And just a little rubber jumper to the frame. I'm down to the last bit of hard line and rubber hose, not enough to finish. So on hold for parts.
Wiring is laid out in the engine room. There is one relay in the harness right next to the fuse. That is going on the firewall right behind the engine. There is enough harness that it can be moved side to side. On a Bronco it would be shifted toward the passenger side and still reach the engine just fine. For the basic install you have 5 wires to deal with. Power and ground. Switched ignition (planning on pulling that off the duraspark, need to check for hot in crank first). That is the 4 wires they tell you makes for an easy install. The 5th wire, you have to do this as well but it is just power to the fuel pump.
Time to order parts. Should be running in a couple of weeks. Stay tuned, more to come.
I have already done some pre install work. Both stock tanks (this will be a 2-tank EFI install) are stock. Lack any baffling. I added a new fuel pickup using a Holley hydramat. The stock pickup sock had already fallen off or fell apart. They will now be the fuel return. In the Hydramat instructions they mention returning the fuel right at the pickup. Do not return it at the top of the tank and allow it to waterfall. I had waterfalled the return in the past. Aerating the fuel. I used a 4-port accumulator to degas the fuel in the past. No accumulator this time. Also looking at stock EFI setups, the return is at the bottom. So both tanks are plumbed for a new pickup, and I drove around with the carb hooked to them so I know they work. When the hydramat goes dry, you are out of gas. Bonus, since it does suck the tank dry I get an extra 2 gallons out of a tank. The rest of the fuel system is experimental. Each tank has its own pump. Both outputs are tied together and feed a single filter. The theory is whichever fuel pump is running, is the delivery pump. The one not running is blocking fuel with the check valve. I remember working on an early 90's F150 that had a similar fuel system. Both tanks Tee'd together with no valve. The return I never figured out. But I figured mine. The entire original fuel system is now the return right down to the fuel selector valve. The selector valve in my case is a simple electric solenoid. Add a standard 5-pin relay. Coil attached to the fuel selector solenoid. Common to the fuel pump wire off the Sniper, Normally closed to the main tank pump, normally open to the aux tank pump. Failure modes, gas goes into the wrong tank. When I am done we will see how good this works.
Also part of the prep was I have an O2 bung welded to the exhaust down pipe. I have been driving it with a generic narrow band O2 installed and spliced into a free coupon Harbor Freight multi-meter. Idle with the carb is a little lean or a little rich depending on what mood it is in. The normal driving is generally a little rich except for fast cruising which was a little lean. A bit difficult to run that spot as it was driving faster than I liked. It was the spot just before you got into the power enrichment or maybe the secondaries. So I know I am starting with a fairly well tuned carb as a reference point. I can play with the choke and watch the meter and know right when I get into the choke as it goes from a rough idle lean cold miss to slightly rich and smooth.
So that is the prep I already did. For reference I have ran a Holley Projection 4Di about 20 years ago. That was an advanced system with an O2 sensor back in the day. Totally out of date today. I am looking forward to this new self learning EFI
Unboxing the EFI it looks good. Went for the classic gold which will mostly hide under the (slightly modified) stock air cleaner. The injectors are in the base, not on top like the old Projection/GM TBI. There is a ring of tiny holes just above the throttle blades for the fuel. No other obstructions, just 4 good sized throttle blades. Although I did notice that the secondary side doesn't open 100%. It opens almost all the way, I am not going to worry about this. The harness looks like good quality. Some over braid was provided but I went on Amazon and picked up some more so I could cover all of the exposed wires. Plenty of wire length on everything, in fact you need to plan a little on the routing to use up the extra wire length. Way better than too short. There are 3 capped vacuum ports on the back. One for ported vacuum (it's weird that it is on the secondary side of the throttle body but with 1:1 linkage it should work). A small manifold vacuum, in my case it will run the vacuum controlled heater valves. And a large vacuum port Holley calls "brake booster" but I will do PCV. It is branched equally to both sides. There is a pipe plugged vacuum port at the front of the throttle body. I would leave that alone. The computer is at the front of the throttle body along with the MAP sensor. It senses the front cavity that the vacuum port shares. I want to make sure this reads true manifold vacuum, not something less as you might get if there is air entering this port. Why is the port there? The Super Sniper kit supports boost, there are ways of blocking the MAP from reading internally and make it read external manifold vacuum/boost. So leave that from vacuum port plugged.
The plan:
I guess I better get to this. I will be doing the install in stages. In fact it is even a recommendation in the Holley instructions. Round one is simply get the EFI running and leave the stock Duraspark untouched (other than pulling switched power and tach signal). Do the basic carb swap approach.
Round 2 will be conversion to computer controlled timing. I am going to make the Duraspark distributor work. I don't see any reason I can't. I know Holley wants you to use there fancy expensive distributor options to make this work. They want an indexable rotor so the spark is on time. I got a couple simple tricks in mind. Stay tuned.
Round 3 is the progressive linkage upgrade. I picked up the simple kit from https://www.efisystempro.com/sniper/sniper-efi-system-components/sniper-efi-progressive-linkage-kit. There is a reason this is #3 instead of #2 in changes. The ported vacuum is on the secondary side of the throttle body. With the Holley supplied 1:1 linkage this works just fine. But with a progressive linkage, there would never be any vacuum advance. Going computer timing first means this isn't a problem. As far as the progressive linkage only opening the secondaries 97% with the simple linkage, that is about what they open to now with the Holley linkage straight out of the box. And it's not like the 250-300HP will be hindered at all by slightly less than 800 CFM the throttle body is rated for.
Kickdown is going to be a problem. When I was at SEMA looking these kits over and asking questions they stated that the old style Ford kickdown doesn't work on the Sniper. People have adapted it to work. I have a kit off the Edelbrock that I really don't like because it sticks out so far but I am going to start with that and see if it will work. Thought about a Lokar cable kickdown. And I am thinking of going electronic and using a diesel shut down solenoid controlled by an Arduino. In short there are options, but if you have a C4 or C6 with the original kickdown rod be warned that there will be challenges ahead for you. And if you have an AOD, you also need to think about the throttle valve won't be paired to the throttle correctly. With the larger throttle body and 1:1 linkage on the secondaries part throttle will be making a lot more engine torque then the TV will be showing. You will probably want to start with the progressive linkage kit so the trans will live through light throttle driving. Hopefully if you are doing a Sniper you won't be dealing with an AOD and will have something a lot newer like a 4R70W.
Well that's it for now. I got it opened, planned, and bolted to the engine. Fuel supply is hooked up. For the low pressure rubber hose I am running Shields barrier marine rubber fuel hose. The pressure side is Earl's vapor guard EFI hose. Not cheap stuff, but they have an inner layer to protect the hose from the fuel. To get the hose to slip over the fitting I wet the connection with a drop of 2-stroke oil (it is designed to mix with fuel and burn in an engine). I am stopped right now because I am missing parts. The return is on hold because I forgot to order the replacement roll of 3/8" tubing. I have the flaring tool to do AN-6 and the feed and return on the EFI are AN-6 fittings. I am going to try to make a one piece return line from the EFI down to the old fuel pump. And just a little rubber jumper to the frame. I'm down to the last bit of hard line and rubber hose, not enough to finish. So on hold for parts.
Wiring is laid out in the engine room. There is one relay in the harness right next to the fuse. That is going on the firewall right behind the engine. There is enough harness that it can be moved side to side. On a Bronco it would be shifted toward the passenger side and still reach the engine just fine. For the basic install you have 5 wires to deal with. Power and ground. Switched ignition (planning on pulling that off the duraspark, need to check for hot in crank first). That is the 4 wires they tell you makes for an easy install. The 5th wire, you have to do this as well but it is just power to the fuel pump.
Time to order parts. Should be running in a couple of weeks. Stay tuned, more to come.
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