100 octane gas?

How much compression can you run with 100 octane gas?

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......

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.

unleaded 100 costs more here that vp110 leaded
hmmmm, still working on understanding that

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.....

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.

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.

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

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

The solid roller in my 408 had a 108 lda and was in at 101.

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.

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

And it sure did. Slowed in a big way.

Any why I add timing when running leaded race gas to help speed the burn............

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......