Red Line 60103 SI-1 Complete Fuel System Cleaner - 15 Ounce (4 Pack)

Excellent results! Easy to use, follow directions and it worked better than expected. I believe that I saw immediate results of smoother acceleration and improved gas mpg from 27 mpg to 34 mpg

I've been using Red Line's SI-1 Complete Fuel System Cleaner for a while now, and it consistently impresses with its performance. This 15-ounce bottle of fuel additive is designed to do exactly what its name suggests: thoroughly clean and protect your vehicle's entire fuel system. It’s particularly effective at tackling deposits that accumulate in injectors, carburetors, valves, and combustion chambers. The blend of high-temp and low-temp detergents is quite potent, ensuring a comprehensive cleanse with just one treatment.Beyond just cleaning, this product also works to prevent future corrosion within the fuel system, which is a significant benefit for long-term engine health. I've noticed a tangible improvement in fuel stability after using it, and it seems to actively reduce the formation of gum and varnish, which can often plague fuel lines. The result is a more efficient fuel burn, which can translate into smoother engine operation and potentially even better mileage. It’s incredibly easy to use – simply pour one bottle into your fuel tank for an effective treatment. For a concentrated cleaner that works with nearly 100% efficiency in a single go, this Red Line SI-1 cleaner truly lives up to its promise of exceeding expectations.

I have had several cars and I have come upon Redline's reputation as perhaps THE premier maker of synthetic lubes; (*cue: AMSOIL trolls, chime in now.) After doing a lot of extensive reading about motor oil on Bob Is The Oil Guy (Google it,) I became convinced that Redline was perhaps THE best oil; and while there is no "best oil," If I was going to spend big money on oil or simply wanted the best, I would choose Redline for its proven reputation with its oils, AND HAVE REMAINED SO EVEN WITH SLIGHT FORMULATION CHANGES (Read up on API SN and how it differs from API SM and API SL, etc, there is less of what was known to be the good stuff and it has been replaced with new good stuff, /endrant) - Or, perhaps, Royal Purple for a high performance, specialty oil. Honorable mentions to Mobil 1 and Pennzoil for ultra good oils as well (do you see what I did there?) On the fence about many others; nothing "wrong" with them, but why buy Castrol...That said, this review is not about motor oil. It is about fuel system treatment. And Redline SI-1 specifically, at that!Now let me tell you why I like this Redline product...Firstly: PEA. I forget what PEA stands for, but, as far as I know, it is about the ONLY chemical or ingredient in a fuel system cleaner or injector cleaner - four categories? Well, if it goes in the fuel, then it goes where the fuel goes... So get the strongest one....... - that ACTUALLY CLEANS. Let us make a list of those that are a SHAM, and really DONT have ANYTHING of VALUE in them:- STP- Slick 50, OLD AND NEW formula..- Lucas (there, I said it. I have some experiences as well as research with products from this company, not relevant to this review.)- Prestone- Pro-Long- SEAFOAM (!!!)- "Most of the shelf".. money-wasters.. makes Walmart happy..-- WHY? BECAUSE THYEY DO NOT HAVE PEA, or VERY LOW AMOUNTS but more like NOT, if you look at Product Data Sheets. Labels lie. Product Material Data Sheets? They don't lie.Now, back to WHAT WORKS: I have found that there are only three, criterion: HIGH IN PEA, therefore WORKS...- Gumout with REGANE (Regane is the PEA, three GUMOUT products have it: The All-In-One, the High Mileage, and another yellow liquid version, High Mileage is Orange and All In One is amber)- Royal Purple MaxClean (** HAS PEA; just different chemicals to MAKE it PEA;)- Redline SI-1.^^ Now.. Out of these three, Redline has the HIGHEST amount of PEA in it. Gumout has a lot, too... And I put one Royal Purple MaxClean in my car recently. I then ran out of gas. >.< Now that wasnt the Royal Purple's fault, it was my fault. THIS TIME, I will put in the Redline SI-1.. because it may work a touch better than the Royal Purple. It also costs $5 less, so, WIN! :)I can't give you MPG differences, but, cars I have used it in, that seem to run smoother EVEN WITH AS LITTLE AS 1oz. PUT IN THE GAS TANK! READ THE DOSING! -YOU ONLY NEED TO PUT IN 1 ounce or so, maybe 3oz to make you feel better but that is maybe a waste, to CLEAN THE FUEL SYSTEM-- - Cars I have used it in, partial list because I honestly do not remember all the cars:1) 1995 Ford Taurus GL, 3.0L Vulcan, likely was a flood car, 182,000 or so miles. Could me a nice car but this one looked nice and was in good cosmetic condition with cold AC.. but was a piece of **** otherwise. Strike One for Taurus. I also had a 99 Sable that was perfect.. RAN BETTER ON FUEL SYSTEM TREATMENT OF REDLINE, JUST SMOOTHER. YOU CAN NOTICE IT IF YOU ARE TUNED TO HOW THE CARS RUNS BEFORE/AFTER WITH A TRAINED EAR AND A FEEL FOR THE CAR AND SOMETIMES TAKE NOTICE OF HOW THE CAR DRIVES WITH THE RADIO OFF AND HOW IT FEELS AND SHIFTS, PERHAPS. JUST SMOOTHER. SAME WAY WHEN YOU CHANGE OIL OR TIRES. YOU CAN TELL. *Car is gone.2) 2000 Volvo V70 XC AWD, ~131,000, 2.4L Turbo I5 - SAME. RAN REAL NICE ON THE REDLINE IN THE TANK. *Car is gone. And no, it wasn't the fuel injectors. Made me love and appreciate Volvos and all other finer cars, this car. Or most of. Some finer cars suck lol. Something about driver error...3) 1993 Chevrolet (get ready for it) "S10 Blazer Tahoe LT." Unknown mileage; engines switched due to issues (?) . RUNS LIKE A DREAM ON REDLINE. RUNS PRETTY GOOD ON GUMOUT TOO BUT REDLINE HAS THE EDGE. *Car is sitting, waiting for work. Going full build with it.4) 1999 Volvo V70 XC AWD, 168,850 miles, - SAME AS THE YEAR 2000 VERSION. *The Redline is going into this car. 3oz initial treatment, though I only need to put in 1oz.. maybe I will.5) 2003 GMC Envoy XL. 167,500 miles; 4.2I Vortec 4200. This car is abused by its mechanic, with overpriced brand new tires and 10W-40 motor oil as well as Lucas oil (straight 80 weight....... !!!!!!) when it says 5W-30 on the cap. Think about that. 5W-30 RIGHT ON THE CA.. No, er are going two or three times as thick, and calling it "better." WHAT??????????? Aint 1960 or 1970 anymore... Anyways... RUNS NICE AND SMOOTH ON THE REDLINE. NO OTHER CLEANERS USED.So, there you have it. This is why I will ONLY buy:1) Gumout at WALMART; It costs less, and is readily available;2) Royal Purple MaxCLEAN; This is the hardest to justify, as it costs $5 more than SI-1, has perhaps slightly not as good results, and I ran out of gas when I put it in. So I couldnt evaluate it properly.. If it runs out of gas after I put it in a half tank I am going to be a complaining consumer to the BBB but lol that wont happen... I will try that one again too, in time, with money...3) So far, the best of the three: This Redline SI-1.^^ This was aimed at some of the posters that leave STUPID reviews! Like "My car ran out of gas. 1 star." These are the "bad review trolls" and they need to be shot and executed by the police in the street in a public forum, like Rome and stuff. These are bad people, these trolls. They need love. And they need Jesus. But notice I am not giving a product a one-star review because I ran out of gas. Take heed, lemmings.:)And, one more thing before I hit "Submit" or "Preview my review:" PEA cleans like dishes in a dishwasher. It breaks down any dirt and stuff in fuel system, and carries it away to combustion. IT DOES NOT CLOG FUEL FILTERS. Now, sure, if your fuel filter is clogged.. Will it carry stuff from it to injectors? NO! Why? because it DISSOLVES IT. Then it goes with fuel flow. So, if using in a dirty system: USE A LOT!! USE the 3 ounces or so! GIVE IT ENOUGH TO DISSOLVE THE DEBRIS AND DIRT YOU EXPECT ARE THERE! Or, better yet, change the fuel filter. It is a little tricky and you must be careful, but on a lot of cars its easy, if its not then again: CLEANER!! :)This product will clean injectors, improve spray patterns, maybe increase VOLUME of fuel to the engine, and clean up "Ethanol poop," gas sucks nowadays, and you are a fool if you are saying that gas doesnt leave the ethanol gummy stuff in its effort to be cheapened for maximum profit, winter-blend gas (the worst,) etc. Ethanol eats rubber and isnt good for fuel systems, so why is it in gas????........... Anyways.. Cleaners DO have a purpose.. Sure, YOUR CAR WILL RUN ON JUST GASOLINE but me myself, I believe in these products that address specific things that were overlooked in the inherent design of "just normal gas delivery."Did you like or dislike my review? I tried to make minimal, or no, typos. Firefox helped by having everything underlined in red that it didnt recognize, and I scanned it twice.. Let me know! :)

Good stuff but shipping was very slow.

Summary:Red Line Complete SI-1 Fuel System Cleaner does what it claims to do.I can report two major improvements in performance, one objective and one a bit subjective.Objective improvement: 45% better gas mileage.Subjective improvement: No longer stalls going up the dreaded hill. This may be partly due to my improved skill with clutch and throttle, but I credit at least part of it to the Red Line Complete treatment.Caveat: Perhaps I am a bit generous with my “informed consumer” filters. One of the claims on the package is, “Regain lost horsepower.” Apply that filter to all of the claims. If your vehicle is performing anywhere near the manufacturer's stated performance, no, this product will not improve it. But if your vehicle is performing poorly in comparison to the manufacturer's statements, and you have any reason to suspect that it is suffering from fuel system fouling, this product might make it better, and the purchase price is a good bet. If you use this product and do not see significant improvement, you have some other problem, and you haven't lost much. If you use this product and see the improvement you want, that's a win.Details:The vehicle: I bought my daughter's disused 2005 Suzuki DS500F that had been sitting in her basement for two years, the engine only having been run briefly once a month or so to make sure it was still in running condition.I installed a new battery changed the oil and oil filter, and inflated the tires. That's it.Initial performance was horrible. After burning out the old gasoline and establishing a new baseline for mpg measurement, I got 43.6 mpg, averaged over three tankfulls, compared to the manufacturer's rating of 56.3 mpg (and some reviewers' seemingly preposterous claims of 65 mpg), and I could not climb the on-ramp from Spit Brook Road eastbound onto the Everett Turnpike northbound without stalling two or three times.Treatment: The bottle says to use the full bottle in 20 gallons of gasoline. My 4.5 gallon tank should only take about a quarter of the bottle. Conveniently, there is a notch in the label to show you the half-bottle point, which should be about right for most contemporary cars. I had to eyeball a quarter of a bottle. (I put a half-bottle in my wife's Ford Escape, but we have not been measuring its performance. Saving the remaining quarter bottle for a follow-up treatment in the bike, but it looks like it won't be needed.)I hoped to see some improvement in my first tank _after_ the treatment. In fact, I saw measurable improvement in the tank in which I used the Red Line Complete (51 mpg).(Shortly after the treatment, my speedometer broke – twice – so I had to reestablish my mpg baseline about four tanks after the treatment.)In the past five tanks after the treatment (and after the second fix to the speedometer), I am averaging 63.1 mpg. Yes, borderline preposterous, but that's why I'm using an average. The best single tank was 69.4 mpg but, OK, I could have overfilled a little on the previous tank and underfilled a little on the subsequent tank, but such errors should smooth out in the average, and it's 63.1 mpg over five tanks.Most of my driving is under highway conditions or nearly so. My daily commute is about 200 feet of city streets, three miles of limited-access highway, and two miles of 45 mph secondary roads, and the reverse for the trip home. My weekend excursions are about 20 mile round trips on secondary roads, and the occasional 260 mile round trip to the White Mountains, mostly on limited-access highways (where I got the 69.4 mpg). Not much city driving.And now I can make that left turn from a stop up a 6% grade with the engine still a little cool without stalling. That may be partly because I've gotten better with the clutch and throttle, but I think it's at least partly because of the Red Line Complete Fuel System Cleaner.I am well pleased with the product, and beyond pleased with the bike.