Why do most bottles of fuel additives say that you have to add it into gas tank before refueling? Won't the product mix well if added to gas tank after filling up?
fuel additive mixing
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Supposedly it'll mix better.
I added a full bottle of SI-1 to a half tank of fuel, then topped off my tank (5 gallons).
I noticed NO difference in driveability. I asked Redline if this was a result of me adding the bottle to a half tank of fuel, the technician said no. He said the product should've mixed just fine, especially since I filled up.
But next time, I'm waiting 'till empty.
I added a full bottle of SI-1 to a half tank of fuel, then topped off my tank (5 gallons).
I noticed NO difference in driveability. I asked Redline if this was a result of me adding the bottle to a half tank of fuel, the technician said no. He said the product should've mixed just fine, especially since I filled up.
But next time, I'm waiting 'till empty.
Look at various cocktails.
Some are made to take advantage of specific gravity, even 'though they are all predominantly ethanol, water and sugar.
If you add an additive to a quiescent tank, it may mix, and it may not.
Add it, and then mix the tank by filling, and it's mixed...full stop.
Some are made to take advantage of specific gravity, even 'though they are all predominantly ethanol, water and sugar.
If you add an additive to a quiescent tank, it may mix, and it may not.
Add it, and then mix the tank by filling, and it's mixed...full stop.
Most fuel tank filler necks have a check valve/flap where it enters the tank. If you add the fuel additive after filling the tank, the additive will just sit in the bottom of the filler neck and may only slowly find it's way into the tank. By adding the additive first and then filling up the fuel tank, you'll be pushing the addative into the tank where it can be mixed properly. You need the pressure/flow of fuel while holding the gun/handle during the filling stage to really push open the spring loaded chack valve. The spring loaded valve/flap isn't so strong that the addative won't find it way into the tank, it's just not the best way to do this. You really need to push the additive into the tank during the filling stage.
Alot of directions on the back label of fuel system cleaners/addatives mention, "running the tank as close to empty" and then adding the chemical first prior to filling. Im not so sure that running the tank to it's lowest comfortable volume is very nessessary as long as the chemical is being mixed properly in the way that I mentioned...Add the chemical and then fill the tank.
Alot of directions on the back label of fuel system cleaners/addatives mention, "running the tank as close to empty" and then adding the chemical first prior to filling. Im not so sure that running the tank to it's lowest comfortable volume is very nessessary as long as the chemical is being mixed properly in the way that I mentioned...Add the chemical and then fill the tank.
I only figured this out because I've replaced several gas tanks in my time and I can't say that all gas tanks have a check valve/flap. Most of the tanks that I've replaced have this flap.
JHZR2
Staff member
turbulent jet mixing (sort of) vs. a slow, easy slide into the tank.
Which do you want?
My biggest fear is that though the rubber in the filler neck is obviously OK for contact with fuel, what if some components are not very good with rubber parts? I then have relatively high concentrations of these things, sitting for relatively long times, in contact with the rubber parts.
Id rather have a stream of fuel wash the additive off and into solution.
Which do you want?
My biggest fear is that though the rubber in the filler neck is obviously OK for contact with fuel, what if some components are not very good with rubber parts? I then have relatively high concentrations of these things, sitting for relatively long times, in contact with the rubber parts.
Id rather have a stream of fuel wash the additive off and into solution.
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I don't want to wait for natural diffusion. Eventually, even though baffled, the sloshing/agitation will mix it ..but who knows what transitional concentration levels you'll be using in the process? The stuff is usually slightly heavier than fuel due to the carrier kero (or something like it).
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