compression with 274cam

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DusterBoy15

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whats the best compression to run with xe274 cam.

i have kb107 pistons already just need to CC the heads and find a gasket
and 91 octane with booster
 
Why 91 octane w/booster?

That cam will run well within a bracket of ratios. Higher the better until fuel becomes an issue. No reason that can not be a pump freindly cam and combo I think.
 
why 91 with booster? thats the highest i can get... actually i can get 100 but thats like 5.00 a gallon
 
Hummmmm I see the delimia.

Try a comteic gasket in a custom thickness. Fel_pro makes a gasket @ .054 thick. You shouldn't really loose the quench to badly and it can help with the lowering of the compresion for octane reasons.

Just thinking outloud
 
I called a few places that make octane booster and it was surprising. They said it will increase octane anywhere from 10-15 points but those points are different then the pump numbers. Those points from the booster are really 1.0-1.5 on top of what even grade you use. Not worth the money unless you trying to stop pinging.
 
17 points would be 92.7 on 91 octane gas. If I were you I would call and hear it from their mouths. Take a good smell at some of that stuff, it smells like kerosene.

I won't every build a motor with the intent of adding booster to every tank. Unless you knew exactly how much more octane you could gain.
 
DusterBoy15 said:
this one says outlaw works but i dont know what RON is
Click to expand...

'RON' means 'Research Octane Rating'

In most countries (including all of Europe and Australia) the "headline" octane that would be shown on the pump is the RON, but in the US & Canada and some other countries the headline number is the average of the RON and the MON, sometimes called the Anti-Knock Index (AKI), Road Octane Number (RdON), Pump Octane Number (PON), or (R+M)/2. Because of the 8 to 10 point difference noted above, this means that the octane in the United States will be about 4 to 5 points lower than the same fuel elsewhere: 87 octane fuel, the "regular" gasoline in the US & Canada would be 91-92 in Europe. However most European pumps deliver 95 (RON) as "regular", equivalent to 90-91 US (R+M)/2, and even deliver 98 (RON) or 100 (RON).
 
also what i found is that toulene and Xylene can be both used at octane boosters as long as mixed correctly but there have questions if it will eat your fuel pump seals
 
Formula #1 - Toluene
R+M/2.........114
Cost...........$2.50/gal
Mixtures with 92 Octane Premium
10%...........94.2 Octane
20%...........96.4 Octane
30%...........98.6 Octane
Notes: Common ingredient in Octane Boosters in a can. 12-16 ounces will only raise octane 2-3 *points*, i.e. from 92 to 92.3. Often costs $3-5 for 12-16 ounces, when it can be purchased for less than $3/gal at chemical supply houses or paint stores.

Formula #2 - Xylene
R+M/2.........117
Cost...........$2.75/gal
Mixtures with 92 Octane Premium
10%...........94.5 Octane
20%...........97.0 Octane
30%...........99.5 Octane
Notes: Similar to Toluene. 12-16 ounces will only raise octane 2-3 *points*, i.e. from 92 to 92.3. Usually mixed with Toluene and advertised as *race formula*.

Formula #3 - Methyl-tertiary-butyl-ether (MTBE)
R+M/2.........118
Cost...........$3.50/gal
Mixtures with 92 Octane Premium
10%...........94.6 Octane
20%...........97.2 Octane
30%...........99.8 Octane
Notes: Oxygenate. Very common in octane booster products. Has lower BTU content than toluene or xylene, but oxygenate effect makes the gasoline burn better and produce more energy.

Formula #4 - Methanol or Ethanol
R+M/2.........101
Cost...........$0.60 - $1.75/gal
Mixtures with 92 Octane Premium
10%...........94.3 Octane (Methanol)
10%...........94.7 Octane (Ethanol)
20%...........Not Recommended
Notes: Methanol is wood alcohol. Ethanol is grain alcohol and found in Gasohol in 10% ratios. Both alcohols are mildly corrosive and will eat gas tank linings, rubber and aluminum if used in excessive ratios. Main ingredient in "Gas Dryers", combine with water.

Formula #5 - Isopropyl Alcohol and Tertiary Butyl Alcohol
R+M/2.........101
Cost...........$0.60-$1.50/gal
Mixtures with 92 Octane Premium
10%...........94.5 Octane
20%...........Not Recommended
30%...........Not Recommended

Notes: Similar to Methanol/Ethanol. Isopropyl Alcohol is simply rubbing alcohol.

Sample Mixture
To make your own octane booster, it is easiest to make up a large batch, and then bottle it up in "dosage-size" uses.
Below is the basic formula of one of the popular octane booster products. To make eight 16 ounce bottles (128 oz = 1 gal):

100 oz of toluene for octane boost
25 oz of mineral spirits (cleaning agent)
3 oz of transmission fluid (lubricating agent)
This product is advertised as "octane booster with cleaning agent *and* lubricating agent!". Diesel fuel or kerosene can be substituted for mineral spirits and light turbine oil can be substituted for transmission fluid. Color can be added with petroleum dyes.
 
Is this going to be your daily driver? If so, better just to stay with the 91. How much do you plan to spend on octane booster on a consistent basis?

Comp Cams website doesn't stipulate a minimum CR requirement for that cam, you can run 9.5 on 91 with an XE274.

I thought you already had a 268?
 
heck no haha its not a dailey driver its a weekened warrior i have the 274 cam
but i asked whats the best compression to run with this cam because i can get higher octane fuel by making it
 
Thrashard340 said:
Is this going to be your daily driver? If so, better just to stay with the 91. How much do you plan to spend on octane booster on a consistent basis?

Comp Cams website doesn't stipulate a minimum CR requirement for that cam, you can run 9.5 on 91 with an XE274.
Click to expand...

I agree with Thrashard340 build it to run on pump gas, you'll be alot better off. Use all that money you'd be throwing away on octane booster on more car parts. 91 octane is expensive enough especially here in California, let alone having to buy octane booster every time you need gas.
 
There's a lot of things involved to determine how much octane you will need. Car weight, convertor,gear,timing curve,initial timing, a/f ratio, etc. Don't see why you wouldn't be safe at 9.5:1. Here in michigan we can still get 94 octane at sunoco stations.
 
sunoco sells 114 from what i heard in pasadena CA

so 91 is fine for 9.5??? why were 10.1 cars able to run with 91 in the 60s?
 
because they had a better overall engine combo. The octane rating you'll need isnt driven by compression rating alone. you must factor in the timing, ability to keep the engine cool etc... I would imagine the quality of gas was also better in the 60s
 
ook but i want the most power out of it so i dont want to retard timing just so i can run higher compression so would 9.5 be the best? becasue i can always swap the gaskets out if i wanted to go higher
 
9.5 is a good average and that cam will bleed off some pressure which will help. I haven't been on this site very long so I don't know your combo.
 
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