octane boosters?

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63dartman

63dartman

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Anyone know of a good brand of octane booster that actually works? I am running close to 10.1 compression and I think the gas here in New Mihico sucks. Best I can get it 91 octane. I have a detonation issue at 60-75 mph when I put the gas pedal to the floor. Doesn't have issues at low speed. I'm not sure if it may be a timing issue or not but thought this would be an easy fix if it's just the gas. Car seems to run fine and I'm not advance a hole bunch. what do you guys think would be a good initial advance? I think I am only running about 10 degrees initial due to detonation beyond that. Could this also be a gas grade issue?
 
Whats your engine temp?How lean are you running?What is the total timing advance?
 
Sounds as if you may have your vacuum advance line connected to ported vacuum vs. timed manifold vacuum.
 
I am at 34 total advance and no vacuum advance. Engine may be trying to get hot but I run a aluminum 26" radiator with a fixed fan and a electric fan out front hasn't ever gone over 200 even on 100 deree days. My carb is a 750 eddie tuned to 15 inches of vacuum.
 
An old trick that is seeing a lot of resurgance (especially with the high boost turbo crowd), is water or water/alcohol injection. It clean & cools the chamber, pistons and valves adn fights detonation. It really does work. I have an old-school Edelbrock injector kit to go into my resto-rod, 10.7:1 compression 440. Check out the offerings on eBay under "water injection" .
 
hey, never heard of the water/alcohol trick. how much do you actually gain from it? i've seen some that look constant, giving better gas milage, and others that look like they act more like a Nitrous Boost. any kits you recommmend?
 
The gain is that your motor is not beating itself to death with detonation. It really doesn't add horsepower.

Chuck
 
o.k. I did some checks and I was running at 15 degrees initial dropped it to 10 and 34 degrees at 3200 or total. no vacuum advance, 15 inches of vacuum. adjusted carb, idles at 800 rpm just like a kitten.....gonna try that and see what happens. thanks for the help guys, as far as the injection do you have to get a special spray bar or something for carbs....very interesting subject though. A inexpensive mod that will help keep your engine from beating itself up. Why hasn't this mod been used more?
 
It was starting to be used in the mid 70's when the gasoline had less anti-knock qualities as it did in the 60's but the 60's and early 70's cars with the higher compression were still around. The simplest version of it had a nozzle mounted in the air cleaner lid and sprayed water into the throttle venturis.

It would not be hard to make your own setup with some patio misters and a windshield washer pump.

Chuck
 
340mopar, very good idea, never even thought about the patio misters......think my neighbors would mind a few misters missing? how do you regulate the misters? Do you just supply a constant mist all the time or should it be progressive?
 
The misters will probably be on the small side of volume needed. You will probably need more than one. The misters atomize the water enough that they won't add too much.

Chuck
 
You would probably have some sort of solenoid hooked up to it.
 
I understand the solenoid turning it on and off. Wouldn't you want more wiper fluid/water at full throttle than at idle though?
 
You don't use the injection at idle or cruise for that matter. You use it in a heavy load situation like full throttle or pulling a hill towing, etc.

Chuck
 
I had a Buick T-type and the water injection really worked nice on it. The knock sensor would back things off and limit power so the water injection kept that from happening. I just used a vacuum switch, a windshield washer pump and got an adjustable nozzle from one of the suppliers of Grand National goodies on the web. (The patio mister idea sounds great!) Took about twenty minutes to install and a week to adjust to work really well. The only issue it ever had was if I was on it hard and then had to brake hard for some reason. The residual pressure in the lines would continue to spray some water into the carb with closed throttle plates, which would result in a real bog when I accelerated again or would occasinally even kill the engine. A rare occurance but it did happen... so keep that in mind when considering the nozzle mounting location for your installation.
 
Oh ya, forgot to mention..... in response to your question about some chemical octane booster....just go down to the paint store and pick up a gallon of Xylene. Works well. Ever read on the gasoline pump where it says contains Xylene and Tolulene? Octane components in gasoline.
 
The modern commercial kits use vacume or knock sensor to regulate injection rate, most are adjustable. the simplest setup uses a throttle position switch or rheostst or even a manual button or switch. I recall a street driven, big-block Ford that cruised Wilshire blvd. in West Los Angeles during the early 60's that had around 13:1 compression. It was a real terror. He'd come into my Shell station and buy windshield washer solution and mix it 50/50 with water in a 1 gallon glass bottle that was strapped to the firewall. He couldn't get above 3,000 rpm under load, without the injector to stop the ping. On a Friday or Saturday night he'd go through a couple gallons of "cool-aid" which is what he called the mixture. The Wickapedia article has a lot of interesting info. especially the part about the 6-cycle engine that runs on fuel and steam. 100 low-lead gas is still readely availible at almost every airport. M
 
You are on the high side of compression for pump gas. I run 11.7 and this is what I do. I can curse and drive on pump gas, but like you, I can not put a load on the engine without detonation.

When I want to run the car hard and use the power it has I put in some 110 octane race fuel. With your compression ratio 5 gallons of race fuel then fill the rest of the tank with the best pump gas you have should work fine.

This is your best and only real option IMHO.

Octane boosters don't work.
 
I've used 104+ brand since the late 70's and have always been happy with it.Currently in my 11-1 340 dart I use one bottle of the black racing formula to 10 gallons of premium.

As far a the paint store those chemicals may boost octane but they also make the motor lazy and slower to rev.Stay away from adding them
 
Great info here. I appreciate all the help. I pulled my plugs and noticed that they may be burning under a lean condition. I opened up the adjustment screws on my edelbrock another 1/4 turn and it seems to have helped the detonation issue. Haven't had enough time to test it for sure but, I think I'm on the right track. I adjusted my carb to edelbrocks specs since I've had it and I believe they have you set it up to a best lean condition or something like that. With the adjustments now it starts to decrease the rpm just slightly and that's where I leave it.
 
The fact that chaning the idle mix helps, is a good indicatorr. However, setting a carb and timing curves requires a lot more effort than turning the idle mixture screws. Sounds like with careful tuning, you can get rid of your issue and run pump fuel. Or if you can't perhaps a local good tuner can do it for you. More than likely, you simply need to replace the step up springs and/or jets/metering rods.
 
I guess I left that part out, oops:) I did change the springs and needles to get rid of a rich condition during all driving conditions. I am running a eddie 750 and at first It was running rich all the time until I swapped out the stock needles and springs. I believe I went two stages lean and that's when the issues started. I probably jumped the gun on my post by not doing enough homework but, I know you guys have alot more experience with these kind of issues than me. I really do appreciate all the help and I apoligize for not giving enough info on my problem. Moper, I think you may be right though, I just recently joined a mopar club and we have a meeting on the 17th, maybe I could get some help from there. stay tuned(or untuned in my case for some good results):):)
 
If you were rich, and went to lean, you may have just gone too far. Generally, a rod change alone up or down one size is the biggest change you want to make. Then, if you can't get it where you need it with that jet, you jet up in size, then start witht he small reods with the bigger jet. think of the jet as the "major" change, and the rods as the "finer adjustment". I think you just went too far. Why did you think it was rich? (edelbrocks are typically lean out of the box on a performance engine)
 
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