Learn something new everyday . . . .

[Roadkill]

Taken from the '58 Caddy manual.

"In order to prevent detonation, a premium gasoline with an octane rating of at least 99 should be used . . . . "

Christ, All this time I've been throwing in 95 . . . . Wonder what difference it'd make . . . ?

[55starchief]

Quoting: Roadkill

Taken from the '58 Caddy manual.

"In order to prevent detonation, a premium gasoline with an octane rating of at least 99 should be used . . . . "

Christ, All this time I've been throwing in 95 . . . . Wonder what difference it'd make . . . ?

it will burn the valves and possibly burn the top of the piston to  point it could fail. Any car running 10-1 comp should be run on super mate

[Roadkill]

Bugger.

Didn't realise it was THAT serious.

Oh, well, It's getting a rebuild anyway.

As a 365ci she's running 10.25:1 . . . As a 390ci it'd be 10.5:1.

[55starchief]

Im pretty sure i did tell you to run it on super when you told me the comp ratio

[55starchief]

you can reduce the temps by running a colder plug if you want to run lower octane fuels

[Roadkill]

Don't mind putting super in . . . especially when she's rebuilt . . . .

[Roadkill]

Another little mystery . . .

That Edelbrock manifold I brought ? - It's obviously a tri-carb set-up - designed for 57-61 Caddies . . . .

Said cars came,  as an option, with 3 x 2 BBL Rochester 2GC carbs.
Which have a 4-pin fixing plate.



The manifold I got is made to take a 3 x 2 BBL carbs with the 3-pin set-up . . . .



This is starting to sound even more interesting . . .

Basically I found a few people who could do 3 Rochesters for around $650 . . . but it turns out this isn't what I need !

[sixpack2639]

At 10.5:1 you may want to add an octane booster along with Super!

When I rebuilt my buddies 454ci V8 (went from 8.25:1 to 10.5:1 comp & from 265bhp to over 500bhp) in his 73 Vette he started out running Super (over here it's only 95-98 octane depending where you go) and had to start adding 104+ Octane Boost as he was experiencing intermittant pinging.

[Roadkill]

Super is 99 over here, but 102 (?) is available - albeit Fooking expensive.

Mind you, compared to U.S prices ALL our fuel is Fooking expensive !!!

[sixpack2639]

We had a station here that sold racing fuel for a while, 105 octane, but at almost $6 a gallon not too many people were buying! LOL

That was several years ago when gas was $.99 a gallon. I can imagine what it would sell for today!!!

[55starchief]

Quoting: sixpack2639

When I rebuilt my buddies 454ci V8 (went from 8.25:1 to 10.5:1 comp & from 265bhp to over 500bhp) in his 73 Vette he started out running Super (over here it's only 95-98 octane depending where you go) and had to start adding 104+ Octane Boost as he was experiencing intermittant pinging.

my boss used to run super with the red turbo 108 octane booster which raises 7 points so he was running almost 110 octane, this was in a evo 6 with 2 bar boost damn that thing shifted with the additive

http://northamericanoil.com/41_turbo108.html\" target=\"_blank\" rel=\"nofollow\">http://northamericanoil.com/41_turbo108.html

there is a guy in the UK who stocks this stuff infact i still have 6 bottles at work on the side. its not cheap though

[55starchief]

this is what you need

http://www.motorshack.com/acatalog/VP_Motorsport_109_Race_Fuel.html\" target=\"_blank\" rel=\"nofollow\">http://www.motorshack.com/acatalog/VP_Motorsport_109_Race_Fuel.html

£64 for 5 US Gallon

[Roadkill]

Quoting: 55starchief

this is what you need

Uh-huh.

Quoting: 55starchief

£64 for 5 US Gallon

Actually £75.34 including the vat.

[55starchief]

Quoting: Roadkill

Actually £75.34 including the vat.

lol £6 a liter

[Roadkill]

Quoting: 55starchief

£6 a liter

And we though 83.9p was bad !

[philoldsmobile]

dont forget that US / UK octaine is different....

i'm guessing that the ratings may well have changed over time too.... if it detonates then use super, if not, then use 95..

odd thing - my bike runs 11.5:1 comp and revs to 11,500, but is fine on 95 octaine!

i guess the ignition timing must be waaay different? i dunno...

[55starchief]

Quoting: philoldsmobile

dont forget that US / UK octaine is different....

yeah here you go

87 octane fuel, the "regular" gasoline in the US and Canada, would be 91-95 (regular) in Europe.

i thought it was the other way around so if its asking for 99 US RON it would need 108 RON in the UK

[philoldsmobile]

yeah, thats whats confusing me...

did the US use some sort of bizare different rating in the 50's?

[55starchief]

Quoting: philoldsmobile

yeah, thats whats confusing me...

did the US use some sort of bizare different rating in the 50's?

Nah i think its more the way they rate RON. We rate it as the highest rating where they rate it as the average if that makes sence

[Titsy]

Don't the yanks use the Motor Octane Number rather than the Research Octane Number...

BTW, the Octane rating of leaded fuels is quite high, might have something to do with things....

[55starchief]

Quoting: Titsy

Motor Octane Number

thought that was only used in aviation

[Titsy]

nope... 'tis in my Bosch Automotive handbook...

[55starchief]

Quoting: wikipedia

Measurement methods

The most common type of octane rating worldwide is the Research Octane Number (RON). RON is determined by running the fuel through a specific test engine with a variable compression ratio under controlled conditions, and comparing these results with those for mixtures of isooctane and n-heptane.

There is another type of octane rating, called Motor Octane Number (MON) or the aviation lean octane rating, which is a better measure of how the fuel behaves when under load. MON testing uses a similar test engine to that used in RON testing, but with a preheated fuel mixture, a higher engine speed, and variable ignition timing to further stress the fuel's knock resistance. Depending on the composition of the fuel, the MON of a modern gasoline will be about 8 to 10 points lower than the RON. Normally fuel specifications require both a minimum RON and a minimum MON.

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 United States 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 and Canada, would be 91-95 (regular) in Europe.

The octane rating may also be a "trade name", with the actual figure being higher than the nominal rating.[citation needed]

It is possible for a fuel to have a RON greater than 100, because isooctane is not the most knock-resistant substance available. Racing fuels, straight ethanol, Avgas and liquified petroleum gas (LPG) typically have octane ratings of 110 or significantly higher - ethanol's RON is 129 (MON 102, AKI 116). Typical "octane booster" additives include tetra-ethyl lead and toluene. Tetra-ethyl lead is easily decomposed to its component radicals, which react with the radicals from the fuel and oxygen that would start the combustion, thereby delaying ignition.

[Titsy]

Quoting: 55starchief

but in the United States 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.

And there we have it....

[55starchief]

Quoting: Titsy

And there we have it....

No its the average of both numbers so they dont list MON or RON, but that still makes our ratings lower than theirs