What's the consensus on today's gas you guys are using? Adding any additives?
I would recommend to ALL owners of pre-Testarossa cars to add Marvel Mystery Oil to your fuel at the recommended dosage of 4oz/10 gals. This will add lubricity to today's "dry" fuels and help the valves in the both the mechanical and electric fuel pumps seal better, thus helping avoid vapor lock. If you can find non-ethanol fuel, that is a very good idea, as it has been heavily documented how ethanol damages the fuel systems in older cars.
No additives, they all pretty much taste the same to me, the moderns do not seem to mind. I mostly go to a nearby station that is the cheapest around (in CA.) The elderly, I treat to some Racing stuff I get nearby also. Good old Sunoco. MMO, have been using but not so disciplined at it
While I’ve personally never experienced problems with ethanol fuels in my vintage cars, perhaps because I drive them more frequently than most owners, I have encountered numerous concerns & damages in vintage cars that don’t see frequent/regular exercise & refueling. Thanks to Dyke’s recommendation, I’ve started using MMO a while back and hoping to see improvements on the infrequently used cars I’ve been maintaining for decades.
Carbureted and CIS cars do not do well sitting for extended periods with modern gasoline blends. Ethanol-free is better if available in your region as determined by EPA. Gasoline composition has changed since carbs and CIS era. Currently lower aromatics (BTX) percentage and added oxygenates (ethanol). Carbs and CIS mixture should be slightly richened from OEM to account for that. Techron or the Redline product for added detergent.
Carb Defender Driven Carb Defender Fuel Additive is specifically formulated to protect against Ethanol corrosion and induction deposits. Special corrosion inhibitors work to prevent expensive repairs and diminished performance caused by Ethanol-blended pump gasoline and the moisture it attracts. These additives control combustion chamber residue, plus they clean and protect surfaces of the fuel system and intake tract. One of Carb Defender’s most important functions is that of a fuel stabilizer that ex-tends fuel storage life. The additives treat up to 25 gallons of Ethanol-blended gas. Carb Defender should be used with each and every fill-up for a 54% improvement in cleanliness. https://drivenracingoil.com/i-30497752-carb-defender-ethanol-fuel-additive-10-oz-bottle.html?q=carb+
Additives - most additives on sale today or a waste of time and money. Buy the wife some flowers instead. For me :- 1) Change all fuel hoses to at least E50 compatible. 2) Use the car frequently or drain the fuel if stored. 3) Ensure the carbs are set up & jetted properly. Stock jets are now suspect to run your car lean. 4) fill up only what you need for a journey, in other words dont overfill the tank. Buy E5 fuel where possible even though some of these "special" high octane fuels have been shown to just be a basic low octane fuel selling at a inflated price..
Ed: No, you are only using 4 oz of Marvel Oil in 10 gal of fuel. A comment about jetting with today's fuels. Today's gas requires approximately 14% more fuel to equal the energy composition from the 1950s-60s fuels. Thus, it would appear jetting should be richened up by 14%. This works with most American cars from that era, but Ferraris are a slightly different animal. In the day, Ferrari jetted the engines slightly rich from the factory, especially at the top end. They did not want to be paying for warranty engine replacements because some idiot ran the car wide open on the autobaun with lower quality gas, so richer jetting prevented a possible burned piston. As a result, we find the factory jetting still works pretty well today for the older Ferraris, as they are rarely driven hard for long periods at high revs. During dyno testing, many times we have to lean the factory jetting for max power when we use race gas.
Thats interesting, on my car when put on the dyno it showed lean 2750 to 4000 and 5750 all the way to max with stock jets E5 fuel.
Tony: It is the fuel! Alcohol needs lots more volume to provide the same power compared to gasoline. When we run methanol in engines they require about 3 times more fuel than gasoline. That is why alcohol fueled race cars get far less mileage than those burning gasoline. E5 is 5% alcohol, and I would expect the engine to require richer jetting to compensate for the fuel.
Let me try to clarify one other point. In a previous post, I stated today's gasoline requires about 14% more fuel by volume to equal 1950s-60s gas. I was referring to NON-ETHANOL gasoline. Things just get worse with ethanol fuels, with larger ethanol percentages needing larger volumes of fuel to produce the same results in the engine.
DWR46 - I changed the AC jets to 195 some years ago if i remember correctly. Made things much better.
Ethanol containing fuels are terrible for any vintage car with carbs, especially one that is driven infrequently. The alcohol can cause float bowls to stick, fuel Iines and seals/gaskets to fail/leak. I use Sunoco 110 leaded, alcohol free, stable in the tank for a very long time (I was told by a distributor easily 2 years). Surprisingly available, expensive but worth it. Here is a locator from the website: https://www.sunocoracefuels.com/fuel-finder
V6 Dino 246. The original spec's are 0.50 idle, tried 0.55 but it was way to rich up to 2,500rpm 220 AC jets, changed to 195 125 mains, retained 120 F24 Emulsion tubes, retained Tony
Toni: You have correctly richened the leanness you encountered on the dyno. Air Correctors mainly effect the top end of the RPM range, while Main Jets will effect the entire range from low to high RPM. I think it is interesting that the engine did not like the 55 Idles. Many times going up one step in Idles really helps these cars with today's fuels.
If your interested, Found the 1st run printout on the dyno. These were std jets, cannot find the corrected graph unfortunately. Tony PS-I had to trace over the line as it had faded. Image Unavailable, Please Login
