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100 octane gas? #2719472
11/26/19 01:56 PM
11/26/19 01:56 PM
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bobs69 Offline OP
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How much compression can you run with 100 octane gas?

Re: 100 octane gas? [Re: bobs69] #2719479
11/26/19 02:33 PM
11/26/19 02:33 PM
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Thumperdart Offline
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I've been running VP-100 and 101 at 12.1.1 comp. in the 9's for many years............The new 101 is called HP-101 and is no longer street legal but VP sez it's good to 14 to 1 iirc w/alum. heads and 12 to 1 w/iron......


72 Dart 470 n/a BB stroker street car `THUMPER`...Check me out on FB Dominic Thumper for videos and lots of carb pics......760-900-3895.....
Re: 100 octane gas? [Re: bobs69] #2719485
11/26/19 02:58 PM
11/26/19 02:58 PM
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BradH Offline
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Originally Posted by bobs69
How much compression can you run with 100 octane gas?

1. It depends

2. Check w/ the fuel blender of your choice to see what their suggested guidelines and/or applications are for whatever they have you're considering using

There's simply no cut-n-dry answer to your question.

Re: 100 octane gas? [Re: BradH] #2719525
11/26/19 05:50 PM
11/26/19 05:50 PM
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oldiron Offline
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unleaded 100 costs more here that vp110 leaded
hmmmm, still working on understanding that


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Re: 100 octane gas? [Re: oldiron] #2719548
11/26/19 08:01 PM
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Thumperdart Offline
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Same here and it went up to $84 a pail so I'm going to 110 leaded and 91 at a 50/50 mix and will see how it runs, how the plugs look and the afr's.....


72 Dart 470 n/a BB stroker street car `THUMPER`...Check me out on FB Dominic Thumper for videos and lots of carb pics......760-900-3895.....
Re: 100 octane gas? [Re: bobs69] #2719638
11/27/19 04:14 AM
11/27/19 04:14 AM
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Agree with Thumperdart at 12:1

I'm at 10.5:1 all day, any weather, any RPM at 92 on an open chamber J head.

Aluminum head and quench, I'd go over 13:1 with 100 octane without even questioning it. twocents

Re: 100 octane gas? [Re: Grizzly] #2719656
11/27/19 08:58 AM
11/27/19 08:58 AM
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mopar dave Offline
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I think most over octane their motors. I don't plan on running much more then 98-101 octane with 12.5:1. I will be mixing like Dom to keep it somewhat economical.

Re: 100 octane gas? [Re: mopar dave] #2719787
11/27/19 03:52 PM
11/27/19 03:52 PM
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Originally Posted by mopar dave
I think most over octane their motors. I don't plan on running much more then 98-101 octane with 12.5:1. I will be mixing like Dom to keep it somewhat economical.


My 434" SB was built for pump 93 and is 11.2-1. When we dynode it I took 5 gallons of pump 93 and 5 gallons of crate 98 race gas. With no changes to the engine it made 30 hp more on the 93 than the 98. The afr and timing were optimized for the 98 before we tried the 93. I've tried unleaded 110 and it doesn't like it either.

I called VP last year and asked for a fuel recommendation for my combo, to my surprise they recommended MS109 oxygenated unleaded. I bought 5 gallons but ended up burning it in my SXS as my Dart didn't like it.

Re: 100 octane gas? [Re: justinp61] #2719794
11/27/19 04:10 PM
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Yep, I seen it at the track . My 408 at 11.3:1 would always slow down with anything but pump gas, i used 93. Many told me i need higher octane at the track with this combo. Vp told me 110 was needed at the track . Well guess what, they were all wrong and now many are finding out that 110 is way too much in a 11:1 motor . Mine my have ran better on 91. Some have said they run 93 pump with 12:1 compression. You just need to keep an eye on things like plugs for instance. My 511 may have ran better that 10.40 if I had ran straight pump 93 in it as well

Re: 100 octane gas? [Re: bobs69] #2719795
11/27/19 04:14 PM
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Originally Posted by bobs69
How much compression can you run with 100 octane gas?


Its more about where your cam is installed(advanced or retarted)
wave

Re: 100 octane gas? [Re: MR_P_BODY] #2719818
11/27/19 05:37 PM
11/27/19 05:37 PM
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mopar dave Offline
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The solid roller in my 408 had a 108 lda and was in at 101.

Re: 100 octane gas? [Re: mopar dave] #2719821
11/27/19 05:46 PM
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madscientist Offline
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There is more to fuel than octane rating. The burn rate is equally important. If you are buying a fuel that has a slower burn rate than pump gas, and you need the quicker burn rate of pump gas it will slow down for sure.


Just because you think it won't make it true. Horsepower is KING. To dispute this is stupid. C. Alston
Re: 100 octane gas? [Re: MR_P_BODY] #2719824
11/27/19 05:54 PM
11/27/19 05:54 PM
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Originally Posted by MR_P_BODY
Originally Posted by bobs69
How much compression can you run with 100 octane gas?


Its more about where your cam is installed(advanced or retarted)
wave

So where your cam is installed is more important than combustion chamber design, bore size, quench area %, quench distance, ignition timing... ?

Re: 100 octane gas? [Re: madscientist] #2719830
11/27/19 06:07 PM
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And it sure did. Slowed in a big way.

Re: 100 octane gas? [Re: madscientist] #2719837
11/27/19 06:35 PM
11/27/19 06:35 PM
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Thumperdart Offline
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Any why I add timing when running leaded race gas to help speed the burn............


72 Dart 470 n/a BB stroker street car `THUMPER`...Check me out on FB Dominic Thumper for videos and lots of carb pics......760-900-3895.....
Re: 100 octane gas? [Re: mopar dave] #2719851
11/27/19 08:02 PM
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I have a customer that runs a Pettis 572 BB Chevy in a 3430lb stock suspension Chevelle that runs on 94 from the pump and has gone a best of a 1.22 60 ft and 8.84 at 150+ so far w/a 1250 2-circuit I built him. He tried av gas and it went slower but no full on race gas yet so maybe next year and I'll report the results......

Last edited by Thumperdart; 11/28/19 01:43 PM.

72 Dart 470 n/a BB stroker street car `THUMPER`...Check me out on FB Dominic Thumper for videos and lots of carb pics......760-900-3895.....




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