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Discussion Starter · #1 ·
I changed my air, oil and fuel filters today. (Also replaced the oil) After my dad got the fuel filter off (I'd never done it before and wanted to see how it was done) he looks at this terribly rusty filter and says "This looks like it could be the original one". So I backed it out of the garage and let it idle.

No more, RPM drop when I put it in gear, no more bubbly suck noise when the fuel pump kicks on and a strong start.

I'm going to put some injector cleaner in the tank tomorrow morning and put some more gas in. I'll tell how it runs now.

All but the oil filter was probably 20,000 miles overdue.
 

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I changed my air, oil and fuel filters today. (Also replaced the oil) After my dad got the fuel filter off (I'd never done it before and wanted to see how it was done) he looks at this terribly rusty filter and says "This looks like it could be the original one". So I backed it out of the garage and let it idle.

No more, RPM drop when I put it in gear, no more bubbly suck noise when the fuel pump kicks on and a strong start.

I'm going to put some injector cleaner in the tank tomorrow morning and put some more gas in. I'll tell how it runs now.

All but the oil filter was probably 20,000 miles overdue.

Don't. Just run premium gas in it for a few tank fulls. Premium fuel contains a bunch of detergents in it that regular and mid-grade do not. That is plenty sufficient to clean them. I personally run premium in all of my vehicles, regardless whether it calls for it or not.

You get better gas mileage with premium. If you calculate it out, you'll realize that it's costing you only about .005 per gallon more than regular.
 

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Don't. Just run premium gas in it for a few tank fulls. Premium fuel contains a bunch of detergents in it that regular and mid-grade do not. That is plenty sufficient to clean them. I personally run premium in all of my vehicles, regardless whether it calls for it or not.

You get better gas mileage with premium. If you calculate it out, you'll realize that it's costing you only about .005 per gallon more than regular.
What are you talking about? Who told you all that? All of what you said is false and incorrect.

Premium fuel is a higher octane but it doesn't contain any more or any less detergents than midgrade or regular. You do not get better gas mileage with Premium fuel. On an SHO you may since Ford 'recommends' premium fuel on that engine. Otherwise, it'll still run 87 just fine.

A Vulcan Taurus is designed for low grade/87 in lower altitude states. To run it with higher octane is kind of a waste of money.

To the OP, if you feel the need to run some injector cleaner through, toss a bottle in per the instructions on the bottle. Good job taking care of the maintenance!
 

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I suggest doing the Sea Foam fog methid, it's in the topic finder on this site. Pour the remaining Sea Foam into the gas when done. Techron concentrate also works good, but do the Sea Foam fog either way, this will remove carbon build up from the engine. Remember to keep up on the oil changes, every 3k when using dino oil, and don't add anything other than engine oil to the oil.
 

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Discussion Starter · #5 ·
Well my car leaks oil so it's constantly being replenished so I don't actually change it completely that often. I usually do every 6, new filter and the works.

I need to find this leak and bring it to its demise!
 

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What are you talking about? Who told you all that? All of what you said is false and incorrect.

Premium fuel is a higher octane but it doesn't contain any more or any less detergents than midgrade or regular. You do not get better gas mileage with Premium fuel. On an SHO you may since Ford 'recommends' premium fuel on that engine. Otherwise, it'll still run 87 just fine.

A Vulcan Taurus is designed for low grade/87 in lower altitude states. To run it with higher octane is kind of a waste of money.

To the OP, if you feel the need to run some injector cleaner through, toss a bottle in per the instructions on the bottle. Good job taking care of the maintenance!
I've worked at several gas stations throughout the years and have talked with several oil company reps, they're the ones that informed me that one of the "bonuses" of running premium is the detergents that are not present in mid-grade or regular.
In addition to that, I have torn down several engines that have run various types of fuels --both fuel injected and carburetor, and without a doubt the ones that have run premium, more so on the carbed engines, have had perfectly clean intake tracts. The engines that were run with regular fuel, definitely had a lot more deposits in the intake runners and on the valves.
And a fun fact about the fuels, dye is typically added to the premium gas. My friend and I used Mobil fuel religiously for years, and when tore down our engines, the intakes were dyed pink from it.

As for gas mileage, that's from personal experience. Obviously the higher compression you have, the more you'll benefit from higher octane. However, on a fuel injected engine (some OBDI but mainly OBDII), when you first start the car (dependent on manufacturer), it'll advance the timing until it knocks, then it backs off a few degrees (within its limits). So another benefit is increased power, granted it's not going to be a helluva lot on a Vulcan, but every little bit helps.
Any way to gas mileage, this is from my own personal testing with a slew of cars from my 400hp '85 Mustang GT, to my 5.0L Ranger, to my '93 Lincoln towncar (4.6L), to my inlaws Lincoln LS, to my Probe GT, to the Tauruses; consistently, all vehicles have gotten better gas mileage with premium fuel. Not to mention they all ran better too.

When you break it down, it costs very little extra to run the good fuel.

And yes, I am very aware of what octane is and how it works (quite the opposite from what most people think).

FWIW, I am a certified mechanic that has been working on cars specifically for over 20 years. 2 stroke Dirtbikes and small engines longer than that.
 

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I would think that the quality of the inside of an engine would be more based on the oil used as well as the frequency of having the oil changed, rather the type of fuel used. But maybe that plays a role from what you're saying? I usually buy brand name gas, and I aim for the pure gasoline instead of "this may contain up to 10% ethanol" junk that takes off an MPG or two.

Like you said, on a Vulcan or something it's almost pointless though. I can see why on your higher power cars like your GT Mustang, 5.0L Ranger, 4.6L towncar, etc. Those are higher output, powerful vehicles with a Compression ratio that is at a higher level.

That's cool that your a mechanic and all, but it seems kinda silly to recommend to someone to run "premium fuel" giving you negligible gains, especially on an everyday car like the DN platform bulls (excluding SHOs). I doubt you could even register the difference on the butt dyno :lol:
 

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I agree with Nick..... there is no evidence that premium fuel has more detergents, etc than 87 octane. By no evidence, I am not including the ads from the fuel suppliers claiming "better performance" from higher grade fuel. I have never heard / seen an ad saying premium had more detergents, etc. If they did have more detergents, it would be advertised as such. There is evedence, however, that running premium in a stock, good condition engine designed for regular does not improve gas mileage and may if fact reduce gas mileage, as premium has slightly less energy content per gallon than 87 octane.
 

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I would think that the quality of the inside of an engine would be more based on the oil used as well as the frequency of having the oil changed, rather the type of fuel used. But maybe that plays a role from what you're saying? I usually buy brand name gas, and I aim for the pure gasoline instead of "this may contain up to 10% ethanol" junk that takes off an MPG or two.
What I was referring to was the intake portion of the engine where no oil is supposed to be. If there is, you have problems.
Oil (usually synthetic) might play a role on higher mileage engines that are more susceptible to blow-by, this would cause oil to get sucked up in to the PCV system and travel through the intake.

Like you said, on a Vulcan or something it's almost pointless though. I can see why on your higher power cars like your GT Mustang, 5.0L Ranger, 4.6L towncar, etc. Those are higher output, powerful vehicles with a Compression ratio that is at a higher level.
While yes, there is a noticeable power increase on cars like my Mustang and Ranger, but then again they have considerably higher compression ratio's than your everyday car. The Stang was 12:1 and the Ranger is ~10.75:1.
However, I'm not suggesting that people run premium indefinitely on low compression engines, as this will, in fact, cause it to lose performance because of the higher octane fuels resistance to ignition, which is why higher compression is required.
The reason I suggested it was because of the detergents to clean out the fuel delivery system, mostly the injectors as sediment from the lower quality fuel can plug up the nozzle's and cause poor fuel atomization.
Then yes, they should revert back to regular. But about 1 tank of month of premium would be beneficial.
Also, note that engines with a lot of miles on them will have accumulated a lot of carbon on the top of the piston. This raises the compression ratio. If you have a higher mileage engine, and you run regular, and you can hear it spark knock (pre-ignite) at higher RPM's, then running premium is a must to prevent irreparable engine damage (melting pistons).
BTW, the Towncars 4.6 is not a higher output engine. It's your typical run of the mill SOHC 4.6L, which I believe is ~9:1, maybe 9.5:1.
That's cool that your a mechanic and all, but it seems kinda silly to recommend to someone to run "premium fuel" giving you negligible gains, especially on an everyday car like the DN platform bulls (excluding SHOs). I doubt you could even register the difference on the butt dyno :lol:
The Duratec engines definitely do benefit from it. Vulcans, not so much. As I mentioned before, I have noticed increased gas mileage and smoother idle and so forth with the better fuel. I'm not into performance as I used to be (got kids now), so I'm not too concerned with the negligible power gains. It's more for increased fuel economy and the detergents to keep the fuel system clean.

I agree with Nick..... there is no evidence that premium fuel has more detergents, etc than 87 octane. By no evidence, I am not including the ads from the fuel suppliers claiming "better performance" from higher grade fuel. I have never heard / seen an ad saying premium had more detergents, etc. If they did have more detergents, it would be advertised as such. There is evedence, however, that running premium in a stock, good condition engine designed for regular does not improve gas mileage and may if fact reduce gas mileage, as premium has slightly less energy content per gallon than 87 octane.
And they are. Just take a look at Shell's V-power fuel. Granted this is the manufacturers webpage, but if the information they were providing was false, then I'm sure they would've been sued for false advertisement/misrepresentation already.

As I've mentioned earlier, I've worked at several corporate store gas stations, and have spoken with their reps. They're the ones that have told me about it. And from my own experience in rebuilding engines, the ones that have had premium for all or most of their "life" were definitely cleaner on the intake side. Granted this is more from carbed engines since the fuel actually travels with down the intake runners and cleans up any sediment left there.

As for decreasing mileage, this can be true on very low compression engines (8-8.5:1). However, on higher compression engines, and the newer cars, as I mentioned before, the engine "senses" the different fuel.
I'll explain again how this works. On most newer cars with OBDII (on board diagnostics 2 (96 and newer cars)), even some OBD I cars, when you first start your car the computer advances the timing until the knock sensor detects knocking (within its available ECU parameters or mechanical limits if using a distributor). Then it retards the timing a few degrees to keep from detonating and/or pre-igniting. This is obviously dictated by the octane of the fuel.
Contrary to popular belief, the higher the octane, the harder it is to ignite (not directing this towards you but other readers). However, as I mentioned before the ECU will advance the timing a lot with the premium fuel as it will not detect knocking until it's advanced much further than with mid-grade or regular.
What does this mean? Well, this allows the premium fuel to burn for a longer period of time across the timing curve, in fact, releasing more energy and thus, you get better mileage.

As I said earlier, the higher the compression, the more of a benefit you'll get. As with my mustang, the mileage difference was astounding. With regular I got approx. 190 per 13 gallons, ~230 with mid-grade, ~275 with premium, and up to 325 with premium mixed with Torco/Turbo blue (110 and 115 octane racing fuels).
 

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You dont really need to explain to me how the EEC IV or EEC V systems work. I already know this stuff. Most cars that have knock sensors do not advance the timing until knock is detected and then retard it a few degrees. Timing advance is preprogrammed in based on RPM, MAF flow rate, IAT, ECT, TPS, etc (most of these are rolled into the load calculation). If the KS does not detect knock, it runs the programmed in timing. Only if knock is detected at the programmed timing for that engine load calculation will the PCM pull a few degrees timing. Remember many engines do not even have a KS. I would say more dont than do.

I fully agree that 93 octane can and will increase performance in engines designed for it. Running lower octane than specified will cause detonation which will cause the KS (if equiped) to pull timing and reduce performance. If not equiped with a KS, running lower octane than required can blow HGs, hole pistons, etc, especially in modified engines (dont ask me how I know this). I will only run 93 in my nitroused 5.0 and my Turbo Coupe, as these were designed for premium. But my Tarui and GP GT get good old 87, and run just fine on it.

IMO, any grade of any good fuel (Tier A fuels) has enough additives to keep a originally clean fuel system clean. If the fuel system is gunked up, injectors partly clogged and so on, it needs to be fixed (injectors cleaned / flowed, etc).
 

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You dont really need to explain to me how the EEC IV or EEC V systems work. I already know this stuff. Most cars that have knock sensors do not advance the timing until knock is detected and then retard it a few degrees. Timing advance is preprogrammed in based on RPM, MAF flow rate, IAT, ECT, TPS, etc (most of these are rolled into the load calculation). If the KS does not detect knock, it runs the programmed in timing. Only if knock is detected at the programmed timing for that engine load calculation will the PCM pull a few degrees timing. Remember many engines do not even have a KS. I would say more dont than do.
It seriously depends on the manufacturer and even the car. I know for a fact that Ford's do do this. However, a lot of the time, the ECU has to be reset in order for it to perform this self test during start up. This is wholly the case with my '94 Probe GT which is OBD I. However, that car is limited by the physical limitations of the distributor.
I also know that a lot of other manufacturers do this as well like Honda for instance, and even that is dependent on the year and even model.
I fully agree that 93 octane can and will increase performance in engines designed for it. Running lower octane than specified will cause detonation which will cause the KS (if equiped) to pull timing and reduce performance. If not equiped with a KS, running lower octane than required can blow HGs, hole pistons, etc, especially in modified engines (dont ask me how I know this). I will only run 93 in my nitroused 5.0 and my Turbo Coupe, as these were designed for premium. But my Tarui and GP GT get good old 87, and run just fine on it.
If your 5.0L is a track only car, then you should be running higher octane than 93. In my '85 I ran Sunoco 94 all the time, and when I went to the track I'd get race fuel (Torco or Turbo Blue preferably) as it was a noticeable power increase. Although, with that car, with race gas, I'd manually advance the base timing. Man that thing ran like a raped ape.

IMO, any grade of any good fuel (Tier A fuels) has enough additives to keep a originally clean fuel system clean. If the fuel system is gunked up, injectors partly clogged and so on, it needs to be fixed (injectors cleaned / flowed, etc).
Well the whole point of it is not allowing it to get plugged (gunked) up in the first place. That's why I run it.
Also, a lot of manufacturers actually dissuade people from using fuel injection cleaners or using the "professional" fuel injection cleaning systems. These have been proven to be too caustic and accelerate the wear of the components. I've actually seen some melt the electrodes off of spark plugs since they're performed with the engine running.

And if 87 works for you, then by all means use it. Although, I think it would be in your best interest to actually test the theory. Be sure to reset the ECU though, otherwise it wont advance the timing.
 

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I fully agree that the "professional" injection cleaners are way too caustic and can easily lead to other problems. If I have clogged injectors (usually on a used car that wasnt taken care of properly by the PO), I pull them and send them out to be cleaned and flow tested.
 
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