Chucker

I checked through the archives and did not find the answer. I found some 110 octain leaded racing fuel in Northern Michighan for $3.50 a gallon. Will this do damage to the 928 engine? I have removed the cats on the car so that's not a problem. I asked DR about this and he was kinda stumped on the leaded part of the question. Any thoughts?

Realist D.

The main problem with leaded fuel in a modern engine is damage to the cats, so you could probably run this in your engine. Although, I'm not sure why you would use 110 octane fuel in an engine that functions properly on lower octane. The simple fact is that the excess octane (and cost) is wasted. You should also be aware that the higher octane would cause the burn to occur at a different temperature, which in-turn changes a number of things related to how your engine works. In order to get your money's worth out of the 110 octane fuel you would need to adjust the compression ratio, valve timing, ignition timing, spark plug heat range, and a whole bunch of other minor tuning-related items. I don't see the point, unless your car runs like absolute crap on the 94 octane fuel you can buy at the local gas station.

fst951

Hey Chucker.

Kinda stumped? Hard to believe. If you indeed have a 1982 US model that operates in conjunction with an oxygen sensor than there is no way you should run leaded fuel! Even with the cats out of the way the lead in the fuel will kill the oxygen sensor rapidly. Otherwise leaded fuel works wonderfully to lubricate and burn smoothly. Tetraethyl Lead, great product to stop detonation and reduce valve train wear, but tough on the environment.

Good luck.

Chucker

Thanks for the replies. I thought about putting it in there because the car is not running perfect. But who's is? I'll change the plugs and run cleaner through the fuel system and stick with the 94.

ViribusUnits

Why even 94???

Assumeing your 82's engine wasn't modified with an incressed compression ratio, it's designed to run on 87.

Buying anything higher is just wasted cash.

If the car is not running right, don't go for higher octane fuel, find out why it's not running right and fix it. The higher octane fuel will not fix it.

Chucker

Viribus, I thought that the 928 ran on about 94 and the loop wire near the fuse panel was for times when only a lower octain was available?

ViribusUnits

Lets see, you have an 82 US right? And you live in the US right?

The car should have a 9:1 nominal CR, and a 4.5l displacement.

Accroding to the WSMs, the car should eat 87 octane juice.

The "low octane loop" is on the 85-86 US cars, with the 10:1 nominal CR. Otherwise, they're suppost to eat 91 octane fuel.

Unless, for some reason your in the US but your working with RON octane rateing. 87 regular by the CLC/AKI rateing system works out to like 92-93 on the RON rateing system. The CLC/AKI is the (R+M)/2 methoid used on the pumps.

The lack of high octane fuel is part of the reason the cars sold in the US have so much lower hp rateing than the cars sold in Europe in the early 80s and late 70s.

Styln928

Chuck . . I was using 93 oct. in my Euro. Ran like stink. I put 87 oct. and Pro Guard fuel injector cleaner in it and it runs fine now. Even with new plugs, cap, rotor & wires it didn't run right. Try it, you may even save 20 cents a gallon for an easy fix.

HTH

jserio

I use cheapo fuel in everything I own. Not for performance, because I'm cheap

Chucker

I bought new plugs today. I'll start there and move on. Thanks for the info Viribus.

Styln928

I can vouch for Joe