fuel recommendations

-
Dave NEO

Dave NEO

Well-Known Member
Joined
Jan 6, 2017
Messages
1,020
Reaction score
259
Location
midwest
'68 383 . Wondering if the Shell 89 is decent enough for this motor, they got higher - do I need it?..
 
Try it and see, but I am betting you need more.
 
so what do you guys run? - in what? can you explain a bit what you mean by how much timing.. thnx
 
The more advance the timing the sooner it sparks. If the octane level isn't high enough the mixture will ignite before the piston gets to top dead center. Which is called detonation.

So when asked how much timing. The amount of initial plus the amount of mechanical plus the amount of vacuum advance (if used).
 
Ethanol free ( if available where you are ) is a better choice. I run higher octane ethanol free, what they call "real gas", in my 67 273. We do run Shells nitrogen enriched regular in our Toyotas.
 
oK guys thanks - our local shell is ethanol free - use 89 in a couple bikes and 93 in 911 I had - I saw some shell comments recommending 89 over their 87 for cars 'designed to run on leaded gas' which I thought was interesting..

CLEAN SHELL GASOLINES

Shell markets three unleaded gasoline grades: Shell Regular, Shell Plus and Shell V-POWER Premium. These three grades of gasoline will meet the octane demands of nearly all engines. Formula Shell Regular typically has an antiknock index of 87*, which is sufficient for most cars designed to use regular unleaded gasoline. Shell Plus (typically, an 89 index*) meets the octane needs of most cars designed to run on leaded regular gasoline, as well as some cars not satisfied by regular unleaded. Shell V-POWER Premium satisfies virtually all engines, and is rated at 93* in the North East Texas market. This Shell premium grade fuel has five times the cleaning additives than mandated by the EPA. V-Power cleans your engine while you drive! With a cleaner engine you may benefit from increased power, lower emmissions and greater mileage.

As engines accumulate miles, they also accumulate deposits in the combustion chamber that usually increase the engine’s octane requirement. The deposits reduce combustion chamber volume, increase the compression ratio and increase octane requirement. The insulating effect of these deposits increases combustion temperatures, which can also increase octane requirement. Shell V-Power gasolines can help to reduce the power and economy robbing deposits. TRY SHELL V-POWER TODAY!

SHELL Gasolines are specially formulated as to their optimum Antiknock Qualities, Volatility, and Oxidation Stability for your climate and geographic area. Octane, Performance and Fuel Economy are carefully controlled to meet the needs of your automobile. Fuel Cleanliness and Handling of the product are closely monitored to bring you the best product possible.

*Octane ratings may vary by market.

WHAT GASOLINE GRADE TO USE
Shell Regular
Unleaded Gasoline - 87 Octane Index. For most vehicles whose manufacturer recommends regular unleaded gasolines.
Shell Plus
Unleaded Gasoline - 89 Octane Index. For most vehicles whose manufacturer recommends leaded regular gasoline, and for those vehicles recommended to use regular unleaded, but engine knocks with regular unleaded.
Shell V-POWER Premium
Shell V-POWER Premium Unleaded Gasoline - 93 Octane Index for all vehicles. This Shell premium grade fuel has five times the cleaning additives than mandated by the EPA. V-Power cleans your engine while you drive!

SHELL LUBRICANT PRODUCTS
Shell offers a complete line of lubricants to meet your needs.
Browse Shell Lubricant Products by Application
 
I run premium in my weedwacker so you can guess what I'm going to say
 
roccodart440 said:
I run premium in my weedwacker so you can guess what I'm going to say
Click to expand...
sounds like a shell commercial ! use the 93 real gas. that was lawnmower gas when I grew up ! our shell stations around here have only 91 .
 
Do you know specs of the motor - especially compression ratio (CR)?

If it is stock '68 383 (or rebuilt to) then CR is 10:1. I'd run octane 91. If it's 383 from another year. See here to check CR. MOPAR MUSCLE | 383 CID B Big Block Engine

You ever hear that "pinging" noise (or Diesel engine like noise) in a car especially under acceleration? That is detonation like Skep explained. Too much timing advance and/or too low octane fuel. Essentially the fuel is "exploding/burning" (fast burn) in the cylinder as the piston is rising in the compression stroke. Not good.

Higher octane then more compression needed to ignite. Lower octane then less compression.

You want the fuel to burn when piston is at top of the stroke.

What fuel is in it now? Does it ping?
 
Last edited:
it's pretty much stock, a rebuilt '68 motor - 10:1 compression, 1010 crank in rebuild, new cam and cam bearings, edelbrock performer alum. intake, Summit 600 CFM double pumper, unsilenced air cleaner, dual exhaust, 3.23 gears... Used 89 without issues for a short time in Fall, but on the trickle charger for a few more months now..91 will burn cleaner anyway right? will likely go with that..
 
Last edited:
Dave NEO said:
it's pretty much stock, a rebuilt '68 motor - 10:1 compression, 1010 crank in rebuild, new cam and cam bearings, edelbrock performer alum. intake, Summit 600 CFM double pumper, unsilenced air cleaner, dual exhaust, 3.23 gears... Used 89 without issues for a short time in Fall, but on the trickle charger for a few more months now..91 will burn cleaner anyway right? will likely go with that..
Click to expand...
IF IT HAS IRON HEADS GO W/ THE 93 .
 
Ok Bob....it does and I will!
PS: you don't have to yell...lol



gas.jpg
 
When you start adding more performance parts- you can run 1 Gallon of AV Gas to 10 Gallons of 93 Octane. I use AV Gas because I have Airport Access, but if you look around- someone within 50 60 miles from you will sell 110 Octane. Only difference's is AV Gas is Blue(from dye) in color and has anti freeze additives. Real Race Gas smells great(smells even better when burning-especially if roasted tires are also cooking) and is crystal clear.
tpg
 
11:1 383 w/ 41* total timing - I run non oxygenated 91 in my car, and will probably add 5 gallon 110 to 10 gallons 91 this summer
 
10.4:1 383 with iron heads 252@.050 cam and timing locked at 38*, reg 93 octane no ping but had a few aluminum specs on 1 plug, mixed 70/30 pump gas and cam 2 no ping and no aluminum lol
 
twayne24365 said:
10.4:1 383 with iron heads 252@.050 cam and timing locked at 38*, reg 93 octane no ping but had a few aluminum specs on 1 plug, mixed 70/30 pump gas and cam 2 no ping and no aluminum lol
Click to expand...

Race only car?
 
famous bob said:
wasn`t yelling, lol, clumsy fingurs !
Click to expand...
you guys do know that b 12 chemtool carb cleaner has 5 diff. octane boosters in it don`t you? can carry a can in the trunk to use at fill up. I used it in my 11 second 406 GMC, and 406 vega. it works, and far far cheaper than any "good" octane booster !
 
roccodart440 said:
Why did you not want any curve in the dizzy?
Click to expand...

never tried different curves. it's a firecore billet piece, pulled it out the box and locked it out, starts very easy, rland runs good.

do you think it would benefit not being locked?
 
twayne24365 said:
10.4:1 383 with iron heads 252@.050 cam and timing locked at 38*, reg 93 octane no ping but had a few aluminum specs on 1 plug, mixed 70/30 pump gas and cam 2 no ping and no aluminum lol
Click to expand...

twayne24365 said:
never tried different curves. it's a firecore billet piece, pulled it out the box and locked it out, starts very easy, rland runs good.

do you think it would benefit not being locked?
Click to expand...

I'm guessing if it wasn't you could get away without mixing fuel and not get aluminum specs or detonation. I'd also play around with the total a little bit just to see what it likes. I run 18/36.
 
You must log in or register to reply here.
-

Back
Top