Premium or Regular Gasoline?
#11
06-15-2012 | 03:59 PM
Senior Member
Joined: Dec 2008
Posts: 2,026
From: Arizona
Well a gross gain of 4 tenths of a second to me is huge. Thats one tenth shy of a half second for a bolt on item.
I never saw those gains on my S-Cars .... Short Ram Intake and a big bore throttle body gave me an average of 1.68 or lets say from 16.500 in the 1/4 to 16.332. A true cold air intake should do better but I never bothered with one. The average I speak of came from four S-Cars. 1998 SW2 manual, 2000 SW2 auto, 2001 SL2 auto and my 2001 SL2 manual. All my cars all made many many passes over the years.
I never saw those gains on my S-Cars .... Short Ram Intake and a big bore throttle body gave me an average of 1.68 or lets say from 16.500 in the 1/4 to 16.332. A true cold air intake should do better but I never bothered with one. The average I speak of came from four S-Cars. 1998 SW2 manual, 2000 SW2 auto, 2001 SL2 auto and my 2001 SL2 manual. All my cars all made many many passes over the years.
#12
06-16-2012 | 08:23 AM
Senior Member
Joined: Mar 2010
Posts: 1,912
From: Peoria AZ
Snip
Now I know this was not done under lab conditions, yet I gave it an over the counter real world shot.
Snip
Not knowing the parameters used by the engine control computers certainly is a swinger in how things will turn out. But reverting back to old school where a person set up those when tuning things it still gets back to compression requires high octane to develop maximum performance how ever one measures it.
The fuel injection conversion I did came with instruction to use 92 octane or higher. Of course Arizona has a maximum of 91.
Why? Probably because there is no knock detection circuitry as part of the conversion.
The tuner built crate engines advertising pump gasoline usage with advertised compression of 10:1 and greater, when asked the manufacturer will generally state 93 octane or better which is not advertised. I have not seen that this side of the Mississippi. Things like the 1000hp Cobra for example. Or multiple small and big block Chevy and Ford engines that are now available.
On my High compression older engines with factory compression ratios near 10:1 tuned for performance it takes gallons of octane boost to even run factory specifications on 91 octane the only thing available here. Unless you are into buying racing gasoline and my real word experiances say pretty much say on newer things drive'm hard through the mountains fully loaded on 7% grades and such they run flat flat with speed with 87 or 89 octane, you can hear and feel it, at least 91 lets them pull hard and don't sound as if they are asthmatic but again it is a perception and I freely admit it. Not to mention the number of times I rebuilt my street racer after blowing pistons into the crank case after detonation set in.
No thanks, you can do what you want, your money, your cars! My money says cheap gas leads to broken expensive engines and decidedly 2nd rate performance and for the difference of 20 cents a gallon which today is less than 5% or so of the total cost of filling the tank rather than the significant number of close to 30% when some of these engine were actually designed and required, premium or ethyl or high octane or what ever the advertising hype called it, I will still use 87 octane as cheap parts cleaner or weed killer and use a minimum of 89 at the pump as cheap insurance against ever having to remove piston parts from places they don't belong anymore. I got tired of that after the second engine. I will no longer build anything with much over a 9:1 compression due to problems with detonation on 91 octane premium.
Again solved when on road trips I get back to areas where 93 octane is available.
So like you said, not labs, it would be nice to have access to a personal dyno. But my real world experience.
My latest engine, purchased from a boat, thus Mercury Marine has World Heads, cast iron. A nice set of heads if you like cast iron ones anyway, the maker of Dart II when they were purchased but installed on a low compression short block so CC out to a smidgeon over 9:1. A dumb move on the builders parts with delusions of grandeur where a lot of money was spent for them with next to no benefit derived, another story not worth repeating. Will work on Arizona's 91 octane with out pinging.
So I kept them. I am about ready to install it in my Hornet Station wagon now that the painting is accomplished. It is getting close now to see how it will run with the CARTER Thermo-Quad carburetor I have. Something that I am pretty sure is about 800 cfm as things are measured. But it has internal compensation for air flow needs and should dial itself out. I'll find out eventually. If it doesn't work out I have a 650 cfm Edelbrock performer that will go on it then.
Now I know this was not done under lab conditions, yet I gave it an over the counter real world shot.
Snip
Not knowing the parameters used by the engine control computers certainly is a swinger in how things will turn out. But reverting back to old school where a person set up those when tuning things it still gets back to compression requires high octane to develop maximum performance how ever one measures it.
The fuel injection conversion I did came with instruction to use 92 octane or higher. Of course Arizona has a maximum of 91.
Why? Probably because there is no knock detection circuitry as part of the conversion.
The tuner built crate engines advertising pump gasoline usage with advertised compression of 10:1 and greater, when asked the manufacturer will generally state 93 octane or better which is not advertised. I have not seen that this side of the Mississippi. Things like the 1000hp Cobra for example. Or multiple small and big block Chevy and Ford engines that are now available.
On my High compression older engines with factory compression ratios near 10:1 tuned for performance it takes gallons of octane boost to even run factory specifications on 91 octane the only thing available here. Unless you are into buying racing gasoline and my real word experiances say pretty much say on newer things drive'm hard through the mountains fully loaded on 7% grades and such they run flat flat with speed with 87 or 89 octane, you can hear and feel it, at least 91 lets them pull hard and don't sound as if they are asthmatic but again it is a perception and I freely admit it. Not to mention the number of times I rebuilt my street racer after blowing pistons into the crank case after detonation set in.
No thanks, you can do what you want, your money, your cars! My money says cheap gas leads to broken expensive engines and decidedly 2nd rate performance and for the difference of 20 cents a gallon which today is less than 5% or so of the total cost of filling the tank rather than the significant number of close to 30% when some of these engine were actually designed and required, premium or ethyl or high octane or what ever the advertising hype called it, I will still use 87 octane as cheap parts cleaner or weed killer and use a minimum of 89 at the pump as cheap insurance against ever having to remove piston parts from places they don't belong anymore. I got tired of that after the second engine. I will no longer build anything with much over a 9:1 compression due to problems with detonation on 91 octane premium.
Again solved when on road trips I get back to areas where 93 octane is available.
So like you said, not labs, it would be nice to have access to a personal dyno. But my real world experience.
My latest engine, purchased from a boat, thus Mercury Marine has World Heads, cast iron. A nice set of heads if you like cast iron ones anyway, the maker of Dart II when they were purchased but installed on a low compression short block so CC out to a smidgeon over 9:1. A dumb move on the builders parts with delusions of grandeur where a lot of money was spent for them with next to no benefit derived, another story not worth repeating. Will work on Arizona's 91 octane with out pinging.
So I kept them. I am about ready to install it in my Hornet Station wagon now that the painting is accomplished. It is getting close now to see how it will run with the CARTER Thermo-Quad carburetor I have. Something that I am pretty sure is about 800 cfm as things are measured. But it has internal compensation for air flow needs and should dial itself out. I'll find out eventually. If it doesn't work out I have a 650 cfm Edelbrock performer that will go on it then.
