Does bottled octane booster work?
 

Hey all,
I just finished a head and camshaft swap. Took my old iron World Products heads off and installed a set of aluminum Dart Pro 1 heads. Went from 72ccc chambers to 64cc, so upped my compression ratio a bit. My truck would previously run on 87 octane just fine, without detonation, though I typically run 91 octane in it, in case I travel to lower altitudes. I live on a mountain, at 6,800' ASL, so I can run a bit more timing without having to worry about detonation. Problem is, my fuel tank is full, and I'm not 100% certain on what fuel is in the tank. I topped it off just prior to tearing into my engine for to cam and head swap.

So, that's a lot of rambling to ask a simple question. But, do any of you know whether the bottles of octane booster actually work? If not, I may just top the tank off with race gas to help bump up the average octane rating. Though, there isn't a ton of room. Of course I can drain the tank, but that is smelly, often messy, and I have to hear the wife complain about the smell of gas.

Re: Does bottled octane booster work?
 

Us they do work, but to what extent based on your needs is the question.

My LT1 383 had 10.7 with a smog legal performance cam. If I poured in $20 of booster my pinging stopped at the 2000-2500 rpm range in OD.

If you have your cam specs I would look up a dynamic compression calculator, and see what it says as point of knowledge.

There is mechanical CR, and Dynamic. We know what mechanical is. Dynamic is a function of mechanical, and camshaft timing. As a sort of theoretical number.

Also tune you carb with a wide band, and vacuum guage. Proper set up will keep a borderline engine in the safe zone.

Re: Does bottled octane booster work?
 

Oh yeah! I always tune with both a vacuum gauge and a FAST dual sensor AFR gauge. I'm not worried about that piece. My static CR is 10.7:1. I have my dynamic CR written down on my cam card, but don't have it handy, nor do I recall exactly what it was. I've done all of the math. I know that I want to run 91 octane do to my compression. My concern was just the existing fuel in my tank, from before the swap, and what effect octane booster will have on that 18 or so gallons. I'm not worried about life beyond that point.

Re: Does bottled octane booster work?
 

Your dancing on the edge, but with a decent performance cam dynamic ratio should be OK.

Testing will be the only way to confirm.

If you are running a Holley 4 hole power valves help with tip in detonation

Re: Does bottled octane booster work?
 

This combo will run fine on 91 octane pump gas. I'm not worried in that respect. Just curious if the bottled octane booster works, for this particular tank of gas. Looking to raise the average octane rating of 18 gallons, IF it is indeed 87, which it probably isn't. Just trying to be cautious.

Re: Does bottled octane booster work?
 

Since I can't find my notes from before, here's what I've got. I shouldn't act like I know that much..
its always good to get another set of eyes on everything! The numbers that I just plugged into my calculator (4.040x3.48, 64cc chambers, 5cc relief, 4.166"x0.039" head gasket) is showing a 10.16:1 static C/R. This info, combined with the camshaft specs is showing a 9.16:1 dynamic C/R!

Advertised cam duration is 302°/302°, with 246° at 0.050" for intake and exhaust. Intake opens 21° BTDC/closes 45° ABDC, w/ 102° lobe center. Exhaust opens 53° BBDC, closes 12° ATDC, w/ 110° lobe center, for an advertised LSA of 106°. This cam produces 246° of duration at 0.050" with the 1.5:1 Comp gold roller rockers that I'm running. Total lift is 0.50"/0.50". I have a set of 1.6:1 roller rockers, too, but didn't think that I would need them. Thoughts?

Notes for this cam state "Very rough idle, high rpm power. Requires 10:1 and higher compression, 3,000+ stall, and gearing. Great bracket race camshaft."

My truck has a 3,000ish stall 10" converter, 4.10 R&P and a 26"-ish tall rear tire.

Looking to swap to a T-56 or Richmond 5 speed soon.

Thanks for looking!

Re: Does bottled octane booster work?
 

Here's what I got. I still use Wallace Racing's site, from my Pontiac days.

Re: Does bottled octane booster work?
 

Note that if you get a different dynamic compression ratio, mine was calculated at 6,800' ASL.

Re: Does bottled octane booster work?
 

I've not tested octane boosters. If it's not already a 10% ethanol gas, you could try adding a gallon of hardware store denatured for a few added octane points.

I think a safer path would be to just run it as is. Retarding the timing, keeping it on level ground, no pulling heavy trailers or other loads, and driving it with a *light foot* will probably get you through that tank without an issue. If your exhaust system is quiet enough to hear knock then you can probably drive pretty confidently. EDIT: And keep the rpms up a little and make sure not to lug it.

Re: Does bottled octane booster work?
 

Yeah, I pumped a gallon out for my snowblower, dumped the octane booster in, broke in the cam and got it all timed and tuned, then ran down to the gas station and topped the tank off with 4 gallons of 91 octane. It worked out just fine. It was probably 91 octane, anyway. I was just being nervous, as I couldn't remember. All is well now!

Re: Does bottled octane booster work?
 

The nice thing about these trucks is that you'll burn through all that gas in no time. :-)

Re: Does bottled octane booster work?
 

There are two kinds of octane boosters. The "104+" from the parts store bumps your octane "2 points" or from 87 to 87.2. You can buy real octane boosters such as VP Octanium which will move your octane 8 numbers, which is 80 points! So on 10 gallons of gas can make 87 gas 95 octane.

https://vpracingfuels.com/product/octanium/?c=367&