I'm driving a ZJ 5.9L and use Super plus fuel (98 octane I believe). Would it do any harm if I add an Octane booster of NOS too it?
The only reason to use higher octane fuel is to help prevent detonation and pre-ignition. In other words if your engine is not pinging/knocking, increasing the octane will do nothing for you. If you want to use an octane booster, there will be no harm done. Contrary to somewhat popular belief, the energy released burning low octane and high octane is virtually identical. Higher octane fuel is not any harder to ignite by the hot spark of a spark plug than lower octane.
Higher octane fuel does burn slower, octane rating is increased only for the resistance of pre-ignition (only). There is no more energy content in higher octane(premium) fuel than regular octane fuel. Actually if you see benefits in running higher octane fuel when its not required, you probably have developing problems with your engine, ignition, or fuel system.
Another thing about increasing octane ratings is, you are not actually getting more octane in the fuel, you are getting a fuel additive that mimics the properties of octane. A lot of products or refineries do this with a Methanol MTBE or Ethanol ETBE base, which could start a whole other arguement about alcohol content in fuel.
Most people who think higher octane fuel is better generally fall into 3 categories,
1. If some is good, more is better right? NO!
2. Label placement at the pump "Premium fuel" Premium must be better than Regular right? NO!
3. More Octane = more power right? No, unless your engine is knocking.
I don't recall ever trying Octane boost with prem gas . I have used it several times over over the years however .
One of the first , was on the Orvis after installing the perf PCM . I had just filled with regular , and the thing pinged like crazy . Instantly , after adding Lucas , it was totally gone . I was pretty impressed with the Lucas for that alone . Great for anyone who's vehicle requires higher octane fuels and only reg. is available .
I also find that I sometimes get better results from Octane boost and regular gas than I do from prem gas (mine both require high oct) . Makes me wonder if I'm not getting shafted paying prem price for regular gas . It's really not hard to notice the difference burning regular gas vs premium in the 5.9 . I have my wife using prem gas in her Aveo . It gets better mileage , and makes the car more tolerable to drive . I can run faster when it's burning reg gas .
Does a higher anti knock index make more power ? No . It maximizes efficiency . I have always found vehicles run smoother on prem fuels , quieter , better throttle responses , and usually better mpg . I find better results from smaller engines more than V8's
Premium fuel fine tunes the timing . By having a higher AKI , it allows the compression stroke to finish before detonation , allowing max compression at the time of ignition . By doing so , it's going to create the most powerful explosion inside the combustion chamber possible for that engine , at the right time .
No , I don't think octane boosts should be used regularly as a dd'er . They do have some good situational uses and I suggest Lucas if your gonna use anything off the shelf . There are properties in the prem gas/additives which can remove carbon build up in engines . This alone can make for better overall efficiency . On vehicles that don't require premium , I think it is good practice to run a tank of premium through every 5th tank . Consider it your monthly additive
To answer the OP's question , prem gas + boost is not recomended . The higher AKI of prem fuel is more than sufficient to maximize benifits . It can be harmful to your emmisions system . It can also rob you of HP at higher rpm's . It will result in build up and deposits on the plugs , fouling them up , with regular use . Next time , I'd suggest google , there's alot better info in the racing world on this subject , I must have read 20 articles and forum debates it was quite educational .
What most people don't read on the bottles of octane booster is that when they say 14 points they mean at most it will raise your octane 1.4. This is not over 93 octane, in most cases it's recorded on 85 or 87 octane. On 93 octane it won't even be close to that. Just run normal premium and you'll be fine.
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@ ratmonkey: I know it wouldn't make my engine run faster, but doesn't it clean (burn) up some carbon build up in the engine? Or will all my seals be roasted?
If you want to do that, get some seafoam and put 1/3 of it in the tank (cleans injectors, lubricated upp), 1/3 in the throttle body while idling (cleans throttle body), and some in the 1/3 in the oil well
this stabilizes fuel, cleans lifters, upper cylinders, lifters, injectors, and removes carbon deposites in the engine. 100% safe!