octane for 425

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NicolasB
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Re: octane for 425

Postby NicolasB » Sun Apr 11, 2021 8:37 pm

I know this thread is old, but would 89 octane be fine for a ‘69 Toronado with 455ci? The gas prices in Cali are getting a bit crazy right now. One place near Big Bear sells premium for $4.75 per gallon! Cheapest premium I found was in Costco for $3.79, which is fine, but there are only so many Costco stations out here.

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xgecko
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Years Owned: My first Toronado was a 1968 W-34 with the bucket seats and center console... (weeps gently) It was a New England rustbucket in 1982 after less than 14 years. So sad. But it is what infected me and before I knew it I had another '68, a '69, a '70 and eventually inherited a friend's '67 and another friends '73. After buying my brand new Grand Prix in 1988 I retired the last of my Toronados and pulled the 455 I had rebuilt along the way and put it into storage in a friend's barn where it is to this day.
In Mid September of 2010 I happened to see a repeat of the show where Jay Leno did his 66 Toronado and had an instant remission of the disease which resulted in my purchase of a 1969 in very good condition. I am now in the process of fully rehabilitating it and hope to have it on the road in the spring of 2011.
Location: Gig Harbor, WA

Re: octane for 425

Postby xgecko » Mon Apr 12, 2021 8:22 am

If you have a stock engine, you need to consider the valves. If they have been modified for Unleaded, which by now one would hope that it has, then it is down to Octane. If not, you have to use an additive designed for lead replacement.

I doubt you can run that motor on 89 Octane if it is stock (10.5:1 compression or thereabouts), it is difficult to run it on 91 or 92. I ran one on 94 back in the day when I could get gas at Sunoco Stations when I lived in New England in the 1980s. Anything less required a fair amount of timing retardation, and that absolutely kills performance.

You might try an Octane Booster with the highest Octane gas you can find, otherwise you will hear Knock or Detonation, which sounds sort of like the engine is gargling marbles, for lack of a better description. This is extremely damaging to engine internals, and if it goes on long enough can crack pistons.

As I noted before, I have used Water injection to deal with this issue, and it was quite successful. I have a kit for my current Motor but am in the process of installing Port Fuel Injection, so it will be a while before I install the Water Injection.
I have my Fuel Injected Toronado. Life is good! 8-)
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bcroe
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Re: octane for 425

Postby bcroe » Mon Apr 12, 2021 9:41 am

Water injection has also worked for me, but keeping it filled up is a pain.
A total redesign for E85 would work. Personally I just use 76 or later engines,
mostly 403s here, which have torque but down on peak HP, but perfectly
happy on the cheapest unleaded. Using an electronic switch pitch controller
on the trans restores much of the performance loss for me. Bruce Roe

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xgecko
Posts: 455
Joined: Wed Oct 13, 2010 9:21 pm
TOA Membership Number: 831
Years Owned: My first Toronado was a 1968 W-34 with the bucket seats and center console... (weeps gently) It was a New England rustbucket in 1982 after less than 14 years. So sad. But it is what infected me and before I knew it I had another '68, a '69, a '70 and eventually inherited a friend's '67 and another friends '73. After buying my brand new Grand Prix in 1988 I retired the last of my Toronados and pulled the 455 I had rebuilt along the way and put it into storage in a friend's barn where it is to this day.
In Mid September of 2010 I happened to see a repeat of the show where Jay Leno did his 66 Toronado and had an instant remission of the disease which resulted in my purchase of a 1969 in very good condition. I am now in the process of fully rehabilitating it and hope to have it on the road in the spring of 2011.
Location: Gig Harbor, WA

Re: octane for 425

Postby xgecko » Mon Apr 12, 2021 10:43 am

I found that modern Aluminum Heads allow me to run on the 92 Octane I can get up here in WA State. I want to add the Water Injection to allow more timing advance which would pull more power out, but I have to convert to MultiPoint Fuel Injection first.
I have my Fuel Injected Toronado. Life is good! 8-)
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NicolasB
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Years Owned: 1969 Oldsmobile Toronado

Re: octane for 425

Postby NicolasB » Mon Apr 12, 2021 11:48 am

Ah okay, I see. I normally premium without additives, like Otto, and the engine sounds fine. With 89, I didn’t hear any pinging or knocking either, but I understand that it doesn’t have to make noise to harm the engine. Water injection seems a bit pricey right now, and octane booster doesn’t seem so bad, but wouldn’t I have to add that every time I fill the tank? The ones I find near my local parts store is 7 bucks so it could also add up. One place in LA sells racing fuel, but it’s $15 a gallon. The timing was originally 10 degrees btc, but I moved it back to the original spec, which is 8 degrees btc. Would that make it accept lower octane fuel?

bcroe
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Re: octane for 425

Postby bcroe » Mon Apr 12, 2021 12:11 pm

xgecko wrote:I want to add the Water Injection to allow more timing advance which would pull more power out, but I have to convert to MultiPoint Fuel Injection first.


Does that mean port injection? Factory intakes are available for big block
Cads and small block Olds, but you need to make your own intake for a big
block Olds. Lots of that done on GMC motorhomes.

A couple decades ago I started work on converting my 79 Eldo to sequential
port injection, since the 403 already had port injection. I did get it running,
but the ACCE... 7 had some hardware and software bugs. Before I could
work out solutions to these, I moved and all that (including the car) got
shelved for quite a while. I am very interested in your equipment plan.

Bruce Roe

NicolasB
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Years Owned: 1969 Oldsmobile Toronado

Re: octane for 425

Postby NicolasB » Mon Apr 12, 2021 12:17 pm

From another classic car forum (Mustang), someone mentioned that the measurement system used back in the 60s for octane was different from what we use nowadays: https://www.allfordmustangs.com/threads ... ed.987649/. Check first and second comment of the thread. I also found this as well: https://www.etuners.gr/fuel/. If this is true, then our Toro’s shouldn’t have a problem with just premium or plus. The lead and unleaded debate I understand, this is more about the pinging issue.

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Otto Skorzeny
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Re: octane for 425

Postby Otto Skorzeny » Mon Apr 12, 2021 12:24 pm

Yes. The modern AKI octane rating is just an average of RON and MON. The seemingly higher octane ratings of the 60s are really about the same as today's octane ratings when calculated using the same formulas.

Premium today is fine for the 425. If your car pings on 93, retard the timing slightly - assuming every other aspect of your ignition system is 100% up to snuff.

In the 60s the octane rating was usually calculated using the RON method. 91 octane (RON) in 1966 is the equivalent of 87 octane (AKI) today. Today's 93 octane fuel is 97-98 octane using the RON method of calculation, which was about the average rating of premium back then.

The whole leaded vs unleaded is BS. The cars don't know the difference.

NicolasB
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Years Owned: 1969 Oldsmobile Toronado

Re: octane for 425

Postby NicolasB » Mon Apr 12, 2021 12:26 pm

Here is another article: http://www.secondchancegarage.com/publi ... soline.cfm.

My Dad has owned many classic cars before and ran them with unleaded. He has never had an issue with any one of them. The only exception was when he ran regular on one of them, but that was it. Premium and plus worked for him.


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