there is a difference between “cheap” and “inexpensive “. I prefer to think that our C4’s are inexpensive, not cheap.

 

Besides the connotation, what would you say the difference is?

 

Semantics.

Some owners use inexpensive gas in their inexpensive Corvette.

Happy now?

Jared

 

Yep. Using an 11 letter word sounds more erudite than a 5 letter word. I

 

The LT1's call for premium recommended. They can run on regular, but at reduced performance. At least that is what the owner's manual states.

In practice some cars are a little different than others. I had a '94 6M that I didn't notice any reduced performance or pinging, but I have had another '94 6M and a '95 6M that it is very noticeable ping and reduced performance (both power and mileage). I suspect that for a highway cruise either might work ok, but for other uses premium was recommended for a reason.

The LT4's it does not say premium recommended, it says premium required.

For your car you can try it and see. Maybe when low on fuel add a half tank regular and see how it works. If bad you can top it off with premium and continue with premium. If ok, you may choose to use regular once in a while or for light loads like when on a highway trip. Just don't plan on using much throttle.

Personally I use premium in my '95, '96, and '99 Corvettes.

Good luck.

 

Is this for real???

Why on earth would you come to that conclusion? All the tach data and hardware on our cars says otherwise. It's amazing what people convince themselves of...in the face of actual facts.

 

Do your research although older tech. the ecm is quite capable of monitoring and adjusting to not only reg/high test but your driving throttle percent to keep you motor at optimal running %

 

Agree with spare parts on the difference between recommended and required. You could run regular all the time and it would not hurt the engine but also you wouldn't get full power.
I have run 87 and 89 (midgrade) a few times in my LT1 and there is a definite loss in performance vs 91 premium. Also with the lower grades I can hear detonation more frequently but nothing that's going to blow the engine... the ECM immediately pulls timing when the knock sensors hear detonation. Only occasionally do I hear detonation with 91, usually while accelerating from low RPM.

 

I made the mistake of putting regular in my 95 during the summer. It did not run as good and at times you can hear it briefly ping until the timing was pulled back.

Gary

 

I'm gonna be blunt, if you're considering running regular vs premium, a corvette isnt the car for you. Get the Buick you really should get instead of a vette. These are sports cars, and consumables are more expensive than other cars.

Personally, I wouldnt want to trust 20+ year old knock sensors to keep timing pulled to run regular all the time. If you're so cheap that you wont run premium gas, you will balk at the cost of other upkeep.

 

My thought was that in comparison to the 5.7 hemi in my RAM which seems to easily control knock when using lower than recommended octane as compared to the 88 5.0 Mustang I had that maybe the difference was the sophistication of the "computer" in newer vehicles vs older. Sorry, I didn't think you'd take it so personally.

 

I didn't. I was more so flummoxed by what "reasoning" must have been used to come to your conclusion....in light of all the readily available facts, data and literature.

The whole thing reminded me of Trumpy; All his experts share facts and data with him...then he goes ahead and creates a baseless fantasy and pons it off on "us" as some f'd up "fact". Seemed like similar logic so you can probably understand my interest!

The '88 Ford Mustang had no feed back for it's ignition control. That car had no knock sensor at all -zero knock sensors..., so there was no possible way for the the ECM to "know" if there was spark knock occurring or not. If it pinged/knocked from low grade gas, it would continue to do so, until it was filled with a better grade of gasoline. The timing control in the Mustang was "blind" w/o that feed back. Also, the ignition system in the Mustang used 4x crank reference system and a time-based timing control. That means that the ECM received 4 reference pulses/crank rotation -so not that precise.

The LT1 has not 1, but 2 knock sensors to provide early feedback to the ECM, in case of knock/pinging. The ECM checks the operation of both sensors and circuits during every start up. Using those sensors, the ignition system/ECM has good feedback, can and does control spark timing nearly instantly to eliminate spark knock/pinging. Additionally, the LT1 uses an ignition system that has a 360x crank reference system and a crank angle-based timing control. This system is far more precise and thus the actual timing control (even w/o the dual knock sensor feed back) is superior to that of the '88 Mustang. In fact, it's actually more precise that the system used in today's DI, LT1/LT4/LT5 engines.

Facts and data....definitely help us to understand what is actually going on, rather than "telling ourselves a story"...then passing it on to others.


.

 

Yep. I've been into Fox body Mustangs for over 30 years. The first (and most simple) modification is to bump the initial/static timing.
Most would fill with premium and then bump the timing until they heard pinging, then back off a hair.
I'm thinkin' this is why CorvetteRules had to run somethin' higher than 87.

 

Isn't that a little too late by the time you hear the pinging over the engine roaring at WOT, which is when much of it will occur?

 

That's what some people say...

But that method has worked GREAT for many, many folks for a long time.

 

Would YOU say that an average human can pick up knock, especially light knocking, from inside the cabin AS WELL AS a knock sensor or two on the block?

 

No. No way.

Does one need to? Probably not. Especially on 80's tech cars.

 

And that is my point. You want the best, don't bet on the human.

Maybe, maybe not but why trust a human when you have a machine already there? More does not hurt, less might.

 

Not sure what you're talking about. '80's mustangs didn't have the "machine already there". The human ear was the best tuning tool...and it worked pretty damn good.

 

In the time spanning the development of the C4, developments implemented took us from ~230 HP to well over 500 HP (gen-II LT5) for a 5.7L capable of smooth idle while driven in summer traffic with the air conditioner running, all the while meeting the (late 80s) EPA mandate that all gasoline automotive engines be capable of operating on 87 octane.

"Being capable to operate and provide highest (output) performance would have been mutually exclusive were it not for improvements in the sensing and controlling abilities of the sensors of conditions and the ability to assess them and effect changes to operating parameters, accordingly!

This fascinating topic is comprehensive, but not difficult to understand, given the right source(s). And, one of my (oft mentioned) favorite sources on this is: "Corvette Fuel Injection and Electronic Engine Management " by Charles Probst. With his help, we can edjimicate ourselves to the level of intelligent posteriors, up from ignorant smart asses!

Bottom line? Yes, your Vette will run on regular as long as you don't expect to get best performance (e.g., the quarter mile or autocross events).


ISBN 0-8376-0861-9 from your local book store or Amazon