additives that actually worked for you

[psudaytona]

Fuel:
FP60 - Cured an injector hiss that has been with the car since I purchased it.
Regane - Helped when I got the car and it had a rough idle.
Redline SI-1 - Best OTC fuel system cleaner IMO. Smoothes the car out really nice and keeps it smooth. I noticed that it made the oil go VERY dark in under a week. The oil was honey colored before it, and within a week of running the bottle, it was all brown...Guess it cleaned soem junk out.
MMO - Helps the engine to be a bit quicker and quieter when started. Also quiets and smoothes the engine out nicely.
Lucas UCL - Same as MMO but it also gives the car more "umph" off the line.

Oil:
Honestly, the only additive I have noticed any real change was LC20. I have used SLOB, VSOT, and LC20 in the oil and only the LC made any change. LC20 made its presence felt within about 15 miles of driving. The engine was smooth before it but after it was VERY quiet(except for the worn lifter tap on the #1 cyl). Also, I noticed that it made the engine alot more "loose" in cold temps. My car runs 10w30 and in december we got a wave of near 0 temps, the engine felt like it was running honey in there in the mornings, didn't want to run really. After running the LC it never had that feeling again. The engine always felt as loose as starting a warm engine.
Another benefit I found with LC was it seems to have totally stopped a small leak from a front seal on the engine. It was minor, but now appears to be totally gone.

 

[marcrosoft]

SFR! (made right in Montana) that is a plus for me since I used to live there I went and talked to the company and got a tour. They actually make the additive unlike some marketing companies. Really great bunch of guys.

 

[Frank]

Please read post "Inside A Volvo" no need to test just read.

 

[BrianWC]

auto-rx in the oil, Chemtool in the combustion chamber.

 

[DracoFelis]

Auto-RX:
Nice engine/transmission/etc cleaner.

VSOT (Valvoline Synpower Oil Treatment):
Nice additive boost, and also a good way to add some extra Moly to the oil. And a small amount of it in the oil (even a good synthetic) seems to quiet down the engine a bit. Like many others on these forums, I do NOT use the whole bottle, but instead stay closer to the 1oz per quart of oil recommendation. Still my experience has been that even a little bit of this stuff in the oil can make a useful improvement.

FP60:
Decent all around gas additive. Seems to cause the engine to run a bit smoother, as well as give me slightly better gas mileage (I found the gas mileage effect was most noticeable in the winter, less so in warm weather). And I also find that my cars are happy on slightly lower octane gas then they used to be. The stuff is also reported to keep the engine cleaner as well as work as a fuel stabilizer (and probably does both things well), but I have no way to verify those latter two claims.

FP3000 (now called "FP Plus"):
I've now switched to this stuff (instead of FP60). It does indeed seem to have all the benefits of FP60, only slightly more so. Also, since the stuff treats 10 gallons of fuel per ounce of additive (vs only 5 gallons for FP60), it's actually cheaper per treatment, despite the fact that the stuff is more expensive to buy than FP60 was. So I find this a win-win (works even better than FP60, and also cheaper to use).

And while not technically an "additive", my recent experiments have shown that my cars seem very happy with me adding a quart or two of good synthetic 0w20 to my oil mix. That seems to be just enough of the "thin oil" to really help the engine turn easily...

 

[Panzerman]

Restore in the chrome metal can, I noticed alot of improvement. It was 1978 Cadillac V8 with 130,000 miles. Slick 50 none, motor honey none stp none allthough my Father swore by it religiously.

 

[BMWR1150GS]

Rislone has cured several noises in several engines for me. I do not use it routinely. Techron works well for me. Diesel Kleen helped improve starting and mileage in my Cat powered motorhome. Moly gear oil additive (Guard Dog Moly) helps reduce friction and heat in the transmission and final drive on my BMW motorcycle.

 

[Gary Allan]

Additives with distinctive results:

Auto-Rx (it's best to have a problem when one looks for the results)
Gumout Regane (profound difference in drivability after use)

Products with passive results: (reduced ignition knock in warmer weather, etc)
Techron
Seafoam

Other:

MMO. I used this in a massive dose, more or less, to prove what it didn't do. I got rewarded with "bump the key" starts for an extended period of time. Pistons had no deposits to speak of ..nor the heads. No UOA with this treat rate ..so I don't know what the extended impact might have been. That makes my evaluation somewhat limited in dimension. Engine still passed the dyno sniffer emissions testing ..even with highly visible vapor trailing out the exhaust.

Soft soot was found on the valves after this massive treatment. It could have been the high treat rate forming its own valve deposits ..or softening up 170k accumulations. Hard to say. The deposits were on both intake and exhaust valves ..the combustion chamber and heads were void of deposits ..and the plugs had some of the same soft soot accumulations (didn't have any effect on starting or running).

I have yet to test Amsoil PI to see if I get the same measurable results I did with Regane. All in due time, I guess.

 

[Mystic]

One group of additives that I left out that could be included would be the Valvoline oil supplement additives. You have to figure that Valvoline knows more about motor oil formulation than any of these people who develop something in a back ally garage. Although I do question why it should be necessary to add something to a quality motor oil nevertheless Valvoline oil with an oz. of the Valvoline synthetic engine treament might make the Valvoline oil just as good as any other.

I second the good opinion about Regane. Be sure to get the Regane in the clear bottle. It makes a difference. I feel it is about the best fuel system cleaner for a reasonable price.

Nothing can beat Auto-RX. You can use it to clean the internals of engines, transmissions, differentials, transfer cases, and power steering units. And the stuff is safer to use.

I think there is no replacing Bars Leaks to prevent cooling system leaks.

And I think there is no replacing Sta-Bil to keep fuel fresh.

I can pretty much stick to these additives and forget the rest.

 

[Stormbringer1992]

Fuel - ACES IV gasoline catalyst

*MPG Increase
*Fuel System Detergency
*Lubricity
*Octane Boost

Oil - Quantum Blue

Only available from bndautomotive.com

 

[Cermax1]

I Have used Cermax
Worked well! Cermax