Does anyone have any recommendations on a good high octane gas additive? I just tuned my Av with the HP III and now the directions say I should use 93 Octane gas. I can't find 93 here in NM. I'm sure someone sells it but I figure I will just go with an additive.
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high Octane gas additive
- Thread starter NMAv
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Tubbyslanche
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tator
Full Member
Go for the free shipping......
Thanks.
Can't you program the Hypertech to use lower octane?
yakmar
Full Member
fireeater said:
Hypertech only has 2 settings :: 87 and 93 ......
And in NM I can't find any place that sells anything with higher than 91 Octane so I'm going to go the additive route for a little while and see if I notice any performance difference. I'll certainly feel it in the wallet....
james21
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Let us know if you have any noticeable differance in performance 
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-James.
.-James.
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Just run it with 91. If you hear knock/pinging then you need the Additive.
JW
JW
I tried this a long time ago had to retune my 327 eng. (warmed over) a 66 Chevelle so NO COMPUTER when i stoped using it had to retune eng. then found a SUNOCO Station close by that had it and started to use Sunoco 260 worked out to be cheper than buying gas then adding additive.
Don't know if you can still buy it but with NASCAR using Sunoco Gas the good stuff may be avalable at some stations, 260 was 110 octain
Don't know if you can still buy it but with NASCAR using Sunoco Gas the good stuff may be avalable at some stations, 260 was 110 octain
JW said:
I was hearing the ping.
dkgz71
Full Member
On the East Coast, BP sells Amoco Ultimate which is 93 octane.
nfhjr said:I tried this a long time ago had to retune my 327 eng. (warmed over) a 66 Chevelle so NO COMPUTER when i stoped using it had to retune eng. then found a SUNOCO Station close by that had it and started to use Sunoco 260 worked out to be cheper than buying gas then adding additive.
Don't know if you can still buy it but with NASCAR using Sunoco Gas the good stuff may be avalable at some stations, 260 was 110 octain
Yep! But we couldn't get it in the West.
james21
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The highest octane I've seen was 95 and it was at a Sunoco. I wonder if that would work well with my AV.
-James.
-James.
Wings
Full Member
I have been down that road with a 450 hp 465 ft-lb 383.
I'm running 10.7:1 forged pistons with Dart Iron Eagle heads along with all the other performance stuff. A good recipe for power and detonation. After a lot of research and hanging around the hot rod people for awhile I found out the bottle stuff you find in the auto stores is not going to alter the octane any discernable amount unless you add something like 20-30 bottles, and then cost becomes prohibitive. One option you have is to use toluene with a small amount of transmission oil mixed in. You will need to add a couple of gallons to a tank of gas. Look close at those little bottles and you will see that most are Toluene or Xylene, both have about 114-116 octane. If you do the math you will see that mixing one pint of 115 with 30 gallons of 83 is going to give you something like 83.1 octane. Some of the better manufactures of these little bottles will say in fine print something like "each octane point is equal to 0.10 of fuel octane"
I'm running 10.7:1 forged pistons with Dart Iron Eagle heads along with all the other performance stuff. A good recipe for power and detonation. After a lot of research and hanging around the hot rod people for awhile I found out the bottle stuff you find in the auto stores is not going to alter the octane any discernable amount unless you add something like 20-30 bottles, and then cost becomes prohibitive. One option you have is to use toluene with a small amount of transmission oil mixed in. You will need to add a couple of gallons to a tank of gas. Look close at those little bottles and you will see that most are Toluene or Xylene, both have about 114-116 octane. If you do the math you will see that mixing one pint of 115 with 30 gallons of 83 is going to give you something like 83.1 octane. Some of the better manufactures of these little bottles will say in fine print something like "each octane point is equal to 0.10 of fuel octane"
If your engine doesn't knock there is no benefit to higher octane.
Timing, compression, boost. These are the things that make more power. As Wings said, these are causes for knock or detonation and where you need higher octane.
Higher octane fuel is just harder to ignite. It doesn't have more power. It allows you to run more timing, compression, or boost without igniting early.
If your engine isn't modified higher octane can hurt performance. A harder to ignite fuel ends up burning in the catalytic converter.
kw
Timing, compression, boost. These are the things that make more power. As Wings said, these are causes for knock or detonation and where you need higher octane.
Higher octane fuel is just harder to ignite. It doesn't have more power. It allows you to run more timing, compression, or boost without igniting early.
If your engine isn't modified higher octane can hurt performance. A harder to ignite fuel ends up burning in the catalytic converter.
kw
I thought that all newer engines had knock sensors. If they detect a knock they will adjust the timing to get rid of it?? I set mine up with the HTTPIII for 93 octane for a while. I never got any knock even if I ran 87 in it. I thought I felt a differance in preformance but when I retuned it for 87 octane it felt the same. I never got a dyno run it is just what I felt.
Butch
Butch
We do have knock detectors and they do retard the timing. That also reduces power.
The timing is only reduced for a few seconds. It ramps back up quickly and stays up where the computer thinks it should be for the load until another knock event occurs.
A readout from my knock detectors shows knock where I don't hear it and doesn't show any when I hear the engine pinging. I don't know what that's about.
kw