Am i retarded ?

[roger longman]

Hi all, Apart from the first 2 weeks after getting the Vette, when I used 91, I have been putting in 87 with no ill effect (that I can determine ) for the last 9 years. Am I deluded,has the computer retarded the spark all this time ? I have never experienced pre-ignition syptoms, of course. Roger.

 

[gmjunkie]

Hi all, Apart from the first 2 weeks after getting the Vette, when I used 91, I have been putting in 87 with no ill effect (that I can determine ) for the last 9 years. Am I deluded,has the computer retarded the spark all this time ? I have never experienced pre-ignition syptoms, of course. Roger.

It won't hurt it,it's designed to run on 87 oct or above!

 

[surfer93]

It will run fine and yes the spark has been retarded, unless you drive w/Datamaster or some other analyzer running, you will never know when your engine knocks from using 87 octane.

 

[roger longman]

It will run fine and yes the spark has been retarded, unless you drive w/Datamaster or some other analyzer running, you will never know when your engine knocks from using 87 octane.

If the ignition is retarded then I am losing power and efficiency aren't I ? I have always been able to hear/feel pinking on any vehicle I have driven or ridden, going back to motorcycles and cars with manual advance/retard. Why wouldn't I be able to tell in a vette ? Many thanks for your input. Roger.

 

[minifridge1138]

As GMJunkie said, the car is designed to run on 87 octane or higher.

If the computer detects an pre-ignition, then it will adjust the timing to prevent damaging the engine.

As for a loss of power, it is probably a fraction of a horsepower at high RPM.
You'd need a dyno to notice.

You said you've been doing it for years and never noticed any ill effects.
Why change now?

 

[gmjunkie]

If the ignition is retarded then I am losing power and efficiency aren't I ? I have always been able to hear/feel pinking on any vehicle I have driven or ridden, going back to motorcycles with manual advance/retard. Why wouldn't I be able to tell in a vette ?

Electronics Dude!!:L
Your car is smarter than most mechanics,it's monitoring every thing and tuning it's self several times a minute,it's when a sensor or a component starts getting out of range and messes with it's brain is when it starts having trouble!
You may notice a power loss,But you probly won't!:L:L:L
If you have been running Regular 87 in it for a long time,you won't even feel it!! The knock sensors hear it long before you can with your ear,It just sets it back just enough to stop it before you can even hear it!
I run All my Corvettes on Chevron 87 except the 69!
If you ran 92-93 in it all the time and then put 87 in it,you would probly notice it a little the first tank maybe two,but I doubt you can tell much difference after that!

 

[roger longman]

Thanks Junk and minifridge, Do you know how many degrees retardation we are talking ? All post 1960 vehicles I had in the U.K. were run on 101-103 but of course compression ratios were much higher. I remember putting kerosene into an old, side valve Ford. It ran just fine (Only for test purposes of course) ! Thanks again. Roger.

 

[gmjunkie]

Thanks Junk and minifridge, Do you know how many degrees retardation we are talking ?

It varies,Just what ever it takes to get rid of any pre-detonation or knock the sensors detect! Air Temp,Humidity,Fuel Quality,all can play a part in it!!
The electronics on these newer cars even adjust somewhat to driving habits!!
My 03 Z-51 coupe does more so than your 88,Technology has came a long ways in the last 20-25 years!!

 

[Vettehead Mikey]

Thanks Junk and minifridge, Do you know how many degrees retardation we are talking ? All post 1960 vehicles I had in the U.K. were run on 101-103 but of course compression ratios were much higher.

You're inadvertently comparing apples and oranges. The UK/Europe and N. America have very different rating scales for petro.... umm gasoline.

Essentially, 87 here is equal to 91-92 over there. 93 here is around 98ish there. 101-103 is long gone everywhere for street use. Our rating scale changed back in the early/mid 70s IIRC. Prior to that it was the same as the UK.

In any case, since your engine was designed to run on 87, it does not ping- so there's no need to for the timing to be retarded. Conversely, there's nothing to be gained by using higher octane gas. Or petrol.

 

[Schrade]

... and yes the spark has been retarded, ...

No, I don't think so - not 87 with stock squeeze.

 

[roger longman]

You're inadvertently comparing apples and oranges. The UK/Europe and N. America have very different rating scales for petro.... umm gasoline.

Essentially, 87 here is equal to 91-92 over there. 93 here is around 98ish there. 101-103 is long gone everywhere for street use. Our rating scale changed back in the early/mid 70s IIRC. Prior to that it was the same as the UK.

In any case, since your engine was designed to run on 87, it does not ping- so there's no need to for the timing to be retarded. Conversely, there's nothing to be gained by using higher octane gas. Or petrol.

I don't think so. As a former costs and statistical analyst with Gulf Oil, I know that : regular in the U.K. is 95 RON, the U.S. it's 90-91. U.K. premium is 97 RON and super is 98-100 RON. 103 RON is still available, in limited supply. If Junk says the spark retards, then it does. I'm curious as to how much. Interesting to hear that you run on apples or oranges up there.

 

[gmjunkie]

If Junk says the spark retards, then it does.

It doesn't retard it all the time,just when it detects a spark knock,and then depending the severity would adjust accordingly! 1/2*,1*-2*-3* Just whatever it takes! The ECM is constantly changeing things like timeing,air fuel mix, depending on Load,Temps,Hudimidity,Fuel,Don't put any E85 in it I don't think it can compensate that far down!