fuel additives & octane boosters

round2K_old · May 3, 2008 at 8:22 AM

I am going to post this question reluctantly as I am fundamentally against fuel additives. Through the years I've tolerated the decline in the quality of gas by gently retarding the timing or tweaking my distributor curves. I no longer want to do that as engines tend to run hotter and performance suffers. When I rebuilt my motor I put it back together with NOS parts and left it stock. The only changes I made for sake of performance and durabilty were porting and polishing the exhaust openings and balancing. The distributor curve was dialed in by Chuck Barbero and I verified that he had it right on the money, and Pony did the carb. In both cases they were left stock, and the timing was set to 12 degrees BTDC as specified, with total advance of 34 degrees when it's all in.

As weather conditions have changed and warmed up I'm getting a little detonation on the highway when I jump on it. Around town and gentle acceleration are fine. I am acquiescing to the reality that it's going to take some octane booster to allow me to run stock compression and stock tuning, and drive the car the way I like to without fear of detonation. I am reluctant to use additives because of experiences I had when I was younger and working in a speed shop. When unleaded fuels were introduced many hot rodders started using boosters and our carburetor overhaul business increased dramatically due to gasket failures from the chemicals, particularly the Holleys.

Has anyone done any research on octane boosters or used any for an extended period of time? If so, what brand are you using?

motor-racer_old · May 3, 2008 at 10:17 AM

For octane booster I use Castrol Valvemaster Plus (Lead replacement petrol additive plus octane boost) which is a phosphorus based product. It is specifically designed and blended for classic cars and I have had no detonation issues at all.

I actually use Castrol product for everything (oil, additive, coolant, etc) because I've had such good experience with it. Probably because they have been doing it for over 100 years.

RROACH_old · May 8, 2008 at 12:33 PM

Hi,I was just wondering some of these questions myself after the last ride in the K!I was running CAM2 but at these prices I would go broke having a joy ride!I have been running SUNOCO94,with generic octane booster from Autozone,actually w no probs.My compression I believe is 10.6:1 running TRW forged pistons from the late 1980s.Anyone know anything about these by the way?I also went to Wal mart and picked up LEAD ADDITIVE in a neat variable amount container which can treat as little as 5 gallons,and will treat up to 160 gallons!This is much cheaper than buying a $3 container every tankfull!It's only $6 or so.I thought it was a cool deal!Anyone have any input?Thanks!Randy

289kford · May 8, 2008 at 12:47 PM

I've been running the lead substitute (I think it's CD2) for more than a couple years nows. It may not do what they say it does, but it has not hurt anything as far as I can tell.

As far as octane boost, Lucas Oil brand ups the number by 30 points, thats 91 to 94. Most others are less than 10 points. I may try some this summer.

5F09C_old · May 8, 2008 at 1:15 PM

Where can I find Castrol Valvemaster Plus in the states? every link I see is UK.

oscart_old · May 8, 2008 at 1:44 PM

Obviously, a good tune is important. The more gear you have the less lugging of the engine you will also have which helps. Make sure that your cooling system is doing its jobs. Engines that run hot are more likely to experience detonation. Modern performance aluminum cylinder heads run cooler and have a more efficient combustion chamber design which really help eliminate detonation. As well, cylinder heads that have been milled excessively, have in effect destroyed the design of the combustion chamber. This will also cause detonation.

But, make sure you are not experiencing pre-ignition. That is a different ball of wax. <img src=images/icon_smile.gif border=0 align=middle>

289kford · May 8, 2008 at 2:14 PM

<BLOCKQUOTE id=quote>quote:<hr height=1 noshade id=quote>

Obviously, a good tune is important. The more gear you have the less lugging of the engine you will also have which helps. <img src=images/icon_smile.gif border=0 align=middle>

wonderful, I just bought some 3.50's to replace the 4.56's.

oscart_old · May 8, 2008 at 2:24 PM

<BLOCKQUOTE id=quote>quote:<hr height=1 noshade id=quote>

Obviously, a good tune is important. The more gear you have the less lugging of the engine you will also have which helps. <img src=images/icon_smile.gif border=0 align=middle>

wonderful, I just bought some 3.50's to replace the 4.56's.

Hmm, well you should run cooler with the 3.50's. <img src=images/icon_smile_approve.gif border=0 align=middle>

motor-racer_old · May 8, 2008 at 2:36 PM

Sorry, yes, I'm in UK and I'm not sure what brand Castrol Valvemaster Plus is marketed under in USA.

Maybe you could ask Castrol USA about it? If they don't already do it, they may import it for you anyway.

289kford · May 8, 2008 at 3:29 PM

<BLOCKQUOTE id=quote>quote:<hr height=1 noshade id=quote>

Where can I find Castrol Valvemaster Plus in the states? every link I see is UK.

Castrol does not list any fuel additives on its USA website. There is a seller on ebay that ships worldwide but I would just get something at a parts store, there has to be a dozen brands you can find.

while looking on the web, I did find (from 1999) a FTC settlement concerning false claims of a Castrol brand fuel additive.

round2K_old · May 8, 2008 at 5:21 PM

I went to Autozone and looked at their shelf full of boosters and reading the labels is like trying to find out the recipe to secret sauce. (Perhaps all too true.) I don't think the Castrol products from the UK can be bought in the US because of lead content. I'll look into the Walmart product, but it's doubtful that it's really tetraethyl lead - perhaps some chemical equivalent.

don_old · May 9, 2008 at 10:16 AM

I've used Octane Supreme 130.

I've used straight AV LL 100

Finally, I've used straight premium 91 octane

No noticeable problems (or benefits) that I could tell.

kgtman_old · May 9, 2008 at 10:41 AM

If it's lead you're looking for in the product, look for a product manufactured in China! <img src=images/icon_smile_big.gif border=0 align=middle>

Tom

5F09C_old · May 9, 2008 at 5:58 PM

That is why I liked the sound of Castrol Valvemaster Plus. Tired of adding led and booster and stuff everytime I fill up. Can you tell I am not green!

Gonna see how much $ shipping will cost me I guess.

motor-racer_old · May 10, 2008 at 1:00 AM

I've sent an email in to Castrol UK technical department to ask them about Valvemaster Plus lead content and exporting to USA. I'll let you know when I hear back.

motor-racer_old · May 12, 2008 at 8:15 AM

This is what Castrol UK technical department repied with :

"The Valvemaster does not contain lead - it is designed to burn and produce a phosphorus ash to protect valve seats. With regard to the USA - I'm afraid I don't know - I would suspect that there is a suitable alternative available in the USA, but best to contact a local dealer there for their advice."

Useful to know it doesn't contain lead so import to USA should be fine. Unfortunately no real information on equivalent products available from Castrol USA.

5F09C_old · May 12, 2008 at 10:19 AM

Thanks, I checked it out and it would cost a ton and there is stuff here that is the same. Thanks though.

rcgt350_old · May 27, 2008 at 1:38 AM

Has anyone used the GUNK lead additive? I don't know much about it?

I inquired about 100LL AV today. The fuel distributor of it says it is a lot drier and doesn't have the same lubricating properties as automotive grade gas, thus it burns so much cleaner as a result. They said you it could possibly dry out the cylinder walls and cause problems that way. They did say that if you mixed say 5 gal. of 100LL with 15 gal of 91 gas that it would be fine and help boost up the 91 number. Any thoughts on this?

Randy

lumpoire · May 27, 2008 at 7:24 AM

You can buy real (tetraethyl) lead additive from this guy;

http://www.jackpodellfuelinjections.com/maxlead.htm

He only sells it by the case ($138+shipping). I have been using it for 3+ years now, with no pinging or any other issues.

Mario

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