shawn, is it alright to do that to a stock engine like ours?? doesnt hurt it at all?? just wondering,,,?Yesterday, I decided to go to my local Alliance gas station that has Trick Racing Gasoline 101 Octane at a separate pump. I had about 6-7 gallons in the tank of Chevron 91, so I decided to see how much of a difference 10 gallons of Trick Racing 101 Octane would make in the STS-V.
All I can say is WOW! The car is ultra smooth and has picked up what it seems like at least 10-15 more hp. With the 101 octane fuel, you don't have to punch it nearly as often as you would with regular 91 octane. You just get on the gas pedal a little and the car goes as if you are on the gas pedal half way.
At WOT, the car simply flies. The front end seemed to lift up and just go with no hesitation. My STS-V has 1600 miles on it and is bone stock with no mods at all and the car really responds to the 101 octane.
It is on the expensive side at $6.49 per gallon but worth every penny when you are driving. I only did a mix, but imagine if you filled up with 17 gallons of pure 101 octane fuel! The car feels like a different animal!
Just thought I would let you guys know that I did a little experiment and how it turned out.
SG
Filled up with 10 gallons of Trick Racing 101 Octane...WOW!!!!!!!!!!
Yesterday, I decided to go to my local Alliance gas station that has Trick Racing Gasoline 101 Octane at a separate pump. I had about 6-7 gallons in the tank of Chevron 91, so I decided to see how much of a difference 10 gallons of Trick Racing 101 Octane would make in the STS-V.
All I can say is WOW! The car is ultra smooth and has picked up what it seems like at least 10-15 more hp. With the 101 octane fuel, you don't have to punch it nearly as often as you would with regular 91 octane. You just get on the gas pedal a little and the car goes as if you are on the gas pedal half way.
At WOT, the car simply flies. The front end seemed to lift up and just go with no hesitation. My STS-V has 1600 miles on it and is bone stock with no mods at all and the car really responds to the 101 octane.
It is on the expensive side at $6.49 per gallon but worth every penny when you are driving. I only did a mix, but imagine if you filled up with 17 gallons of pure 101 octane fuel! The car feels like a different animal!
Just thought I would let you guys know that I did a little experiment and how it turned out.
SG
All I can say is WOW! The car is ultra smooth and has picked up what it seems like at least 10-15 more hp. With the 101 octane fuel, you don't have to punch it nearly as often as you would with regular 91 octane. You just get on the gas pedal a little and the car goes as if you are on the gas pedal half way.
At WOT, the car simply flies. The front end seemed to lift up and just go with no hesitation. My STS-V has 1600 miles on it and is bone stock with no mods at all and the car really responds to the 101 octane.
It is on the expensive side at $6.49 per gallon but worth every penny when you are driving. I only did a mix, but imagine if you filled up with 17 gallons of pure 101 octane fuel! The car feels like a different animal!
Just thought I would let you guys know that I did a little experiment and how it turned out.
SG
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shawn, is it alright to do that to a stock engine like ours?? doesnt hurt it at all?? just wondering,,,?
It is fine to run the 101 octane, especially in a supercharged car like ours. I did a 60/40 mix so it isn't a true 101 octane tankful. It is more like a 95 or 96 octane rating which is just fine.shawn, is it alright to do that to a stock engine like ours?? doesnt hurt it at all?? just wondering,,,?
Guys on the east coast get 93 or higher octane standard at the pumps and GM recommends higher octane for the best performance. Us Cali guys can only get 91 octane which isn't the best for a supercharged car.
My STS-V in stock form flies with the fuel mix. I did 125 MPH on the highway today and it did it effortlessly. With 91 straight, it would take effort to get up to that speed. Mine did it so quickly, I was amazed!
SG
Why would this make a difference, unless in stock trim, the car is pulling timming due to knock?
-Chris
-Chris
Yup! We've heard many people mention that high(er) octane gas will wake these cars up. Reportedly 10-15RWHP worth in some instances.
So I see you're getting ready for the new intake pipes by teasing yourself with more power =)
Craig
So I see you're getting ready for the new intake pipes by teasing yourself with more power =)
Craig
I gotta agree with Trukk. It has to be the placebo effect and the seat of the pants dyno is basically useless and inadmissable in this court. No venom and don't take it the wrong way, but higher octane just means that more anti-knock additives have been added to the same fuel that is 87 rated. There is no more "energy" in the gas and higher octanes make the fuel less likely to combust. Example, higher compression engines with high energy ignitions will tend to pre-detonate the fuel causing the engine to knock. Also, top fuel and alky engines use different fuel and can produce more horsepower, but these are different setups entirely. If you don't belive me, then here are some links.
http://oldeloohuis.com/octane3.html
http://oldeloohuis.com/octane2.html
http://auto.howstuffworks.com/question90.htm
And for the record, I only use 87 octane and my seat of the pants dynometer can't tell the difference...Neither can the LS6, as it has never knocked.
http://oldeloohuis.com/octane3.html
http://oldeloohuis.com/octane2.html
http://auto.howstuffworks.com/question90.htm
And for the record, I only use 87 octane and my seat of the pants dynometer can't tell the difference...Neither can the LS6, as it has never knocked.
Are you tuned? If not there is at least some level of knock that is occuring at SOME POINT. The computer will retard the timing on its own, but only when it detects the knock. Its not a huge deal unless you plan on owning the car along time, as it can result in damage over the long haul. I put 87 in my Escalade but I have no intentions of keeping it beyond 2 years. Also, I do get better fuel economy on mid or premium, so its kind of a tossup.I gotta agree with Trukk. It has to be the placebo effect and the seat of the pants dyno is basically useless and inadmissable in this court. No venom and don't take it the wrong way, but higher octane just means that more anti-knock additives have been added to the same fuel that is 87 rated. There is no more "energy" in the gas and higher octanes make the fuel less likely to combust. Example, higher compression engines with high energy ignitions will tend to pre-detonate the fuel causing the engine to knock. Also, top fuel and alky engines use different fuel and can produce more horsepower, but these are different setups entirely. If you don't belive me, then here are some links.
http://oldeloohuis.com/octane3.html
http://oldeloohuis.com/octane2.html
http://auto.howstuffworks.com/question90.htm
And for the record, I only use 87 octane and my seat of the pants dynometer can't tell the difference...Neither can the LS6, as it has never knocked.
You are fooling youself, not the PCM...which has obviously moved you to the low octane maps with less timing(=less power) and richer fuel mixture (again = less power) as a survival tactic. It's just not going to let YOU destroy it. And your seat of the pants dyno needs to be recalibrated. I use my V-Tech to tell what makes a difference and what doesn't and the only vehicle I own that can use a lower octane gas with no difference is my slightly modified 454SS pickup(7.9:1 compression) in which I use 89 octane.I gotta agree with Trukk. It has to be the placebo effect and the seat of the pants dyno is basically useless and inadmissable in this court. No venom and don't take it the wrong way, but higher octane just means that more anti-knock additives have been added to the same fuel that is 87 rated. There is no more "energy" in the gas and higher octanes make the fuel less likely to combust. Example, higher compression engines with high energy ignitions will tend to pre-detonate the fuel causing the engine to knock. Also, top fuel and alky engines use different fuel and can produce more horsepower, but these are different setups entirely. If you don't belive me, then here are some links.
http://oldeloohuis.com/octane3.html
http://oldeloohuis.com/octane2.html
http://auto.howstuffworks.com/question90.htm
And for the record, I only use 87 octane and my seat of the pants dynometer can't tell the difference...Neither can the LS6, as it has never knocked.
I agree 100%. Lower octane wants to detonate easier than the higher octane. This makes the engine retard its timing (changing spark to detonate well after top dead center) resulting in a loss of compression/power. Higher octane burns slower and lets the car adjust to a timing to more close to top dead center. rsulting in higher compression/power. I also agree I would like to see a dyno of a 91 rating after a full tank then a dyno of a 101 after a full tank just to see if there is a large difference. I'd bet there is some increase in power and or efficiency. Maybe not so much in the HP range but TQ may be jumping higher at a lower RPM resulting in an increase of "seat of the pants" acceleration.You are fooling youself, not the PCM...which has obviously moved you to the low octane maps with less timing(=less power) and richer fuel mixture (again = less power) as a survival tactic. It's just not going to let YOU destroy it. And your seat of the pants dyno needs to be recalibrated. I use my V-Tech to tell what makes a difference and what doesn't and the only vehicle I own that can use a lower octane gas with no difference is my slightly modified 454SS pickup(7.9:1 compression) in which I use 89 octane.
There are numerous dyno tests that the difference was like 1% change in just increasing the octane number in the same formulated gasoline. Race fuels can have different formulations depending upon which refinery produced it. About knocking, I have never heard nor felt my engine knock. The knock sensors have to be activated in order for the timing to be retarded. They are reactive not preventative sensors. Much the same way traction control will come on after the tires slip, they cannot forsee that the tire will slip.
Now the O2 sensor is adaptive with the PCM and that is why you will get different "maps" from among other things such as driving style etc. There is absolutely no difference in 87, 89, 91, 92, or 93 octane ratings other than an additive to increase the octane rating. There is no seat of the pants difference either.
If that was the case, why wouldn't the gas companies advertise that you get more horsepower from higher octane? Don't you think they would just LOVE to do this? They can't because it would be misleading and they would be fined. So please everyone, smarten up. Octane rating has nothing to do with horsepower.
Now the O2 sensor is adaptive with the PCM and that is why you will get different "maps" from among other things such as driving style etc. There is absolutely no difference in 87, 89, 91, 92, or 93 octane ratings other than an additive to increase the octane rating. There is no seat of the pants difference either.
If that was the case, why wouldn't the gas companies advertise that you get more horsepower from higher octane? Don't you think they would just LOVE to do this? They can't because it would be misleading and they would be fined. So please everyone, smarten up. Octane rating has nothing to do with horsepower.
The additive to make octane higher in gas is..... OCTANE. That's what raises the leve of OCTANE. Octane slows the burn rate of gas. A dodge that is tuned for low octane (87)does not run that well on 93 and Vice versa so there is something to the timing as related to Octane. As for you hearing knock you probably won't, if the sensor is doing its job. You would only see the knock condition if you were monitoring a Wide band or some kind of software that monitors all the engines conditions real time on a lap-top.
We may not agree the value added or lack of value added by higher octane, BUT we can all agree the STS-V is one SWEET ride either way......
This is right out of the STS owners manual, which you have not read.There are numerous dyno tests that the difference was like 1% change in just increasing the octane number in the same formulated gasoline. Race fuels can have different formulations depending upon which refinery produced it. About knocking, I have never heard nor felt my engine knock. The knock sensors have to be activated in order for the timing to be retarded. They are reactive not preventative sensors. Much the same way traction control will come on after the tires slip, they cannot forsee that the tire will slip.
Now the O2 sensor is adaptive with the PCM and that is why you will get different "maps" from among other things such as driving style etc. There is absolutely no difference in 87, 89, 91, 92, or 93 octane ratings other than an additive to increase the octane rating. There is no seat of the pants difference either.
If that was the case, why wouldn't the gas companies advertise that you get more horsepower from higher octane? Don't you think they would just LOVE to do this? They can't because it would be misleading and they would be fined. So please everyone, smarten up. Octane rating has nothing to do with horsepower.
Gasoline Octane
If your vehicle has the 3.6L V6 engine (VIN Code 7), use regular unleaded gasoline with a posted octane rating of 87 or higher. For best performance or trailer towing, you may choose to use middle grade 89 octane unleaded gasoline. If the octane rating is less than 87, you may notice an audible knocking noise when you drive, commonly referred to as spark knock. If this occurs, use a gasoline rated at 87 octane or higher as soon as possible. If you are using gasoline rated at 87 octane or higher and you hear heavy knocking, your engine needs service.
If your vehicle has the 4.6L V8 engine (VIN Code A), use premium unleaded gasoline with a posted octane rating of 91 or higher. You may also use regular unleaded gasoline rated at 87 octane or higher, but your vehicle's acceleration may be slightly reduced, and you may notice a slight audible knocking noise, commonly referred to as spark knock. If the octane is less than 87, you may notice a heavy knocking noise when you drive. If this occurs, use a gasoline rated at 87 octane or higher as soon as possible. Otherwise, you might damage your engine. If you are using gasoline rated at 87 octane or higher and you hear heavy knocking, your engine needs service.
If your vehicle has the 4.4L V8 engine (VIN Code D), use premium unleaded gasoline with a posted octane rating of 91 or higher. For best performance, use premium unleaded gasoline with a posted octane rating of 93. In an emergency, you can use regular unleaded gasoline with an octane rating of 87 or higher. If 87 octane fuel is used, do not perform any aggressive driving maneuvers such as wide open throttle applications. You may also hear audible spark knock during acceleration. Refill your tank with premium fuel as soon as possible to avoid damaging your engine. If you are using gasoline rated at 91 octane or higher and you hear heavy knocking, your engine needs service.
You are right...octane has nothing to do with horsepower, it has to do with REQUIREMENT, due to static and dynamic compression ratios in the engine. You will make more horsepower on higher octane fuel if you engine is smart enough to take advantage of it...our cars are.
:food-snacking: I always love to see these threads on gasoline octane.
This is right out of the STS owners manual, which you have not read.
Gasoline Octane
If your vehicle has the 3.6L V6 engine (VIN Code 7), use regular unleaded gasoline with a posted octane rating of 87 or higher. For best performance or trailer towing, you may choose to use middle grade 89 octane unleaded gasoline. If the octane rating is less than 87, you may notice an audible knocking noise when you drive, commonly referred to as spark knock. If this occurs, use a gasoline rated at 87 octane or higher as soon as possible. If you are using gasoline rated at 87 octane or higher and you hear heavy knocking, your engine needs service.
If your vehicle has the 4.6L V8 engine (VIN Code A), use premium unleaded gasoline with a posted octane rating of 91 or higher. You may also use regular unleaded gasoline rated at 87 octane or higher, but your vehicle's acceleration may be slightly reduced, and you may notice a slight audible knocking noise, commonly referred to as spark knock. If the octane is less than 87, you may notice a heavy knocking noise when you drive. If this occurs, use a gasoline rated at 87 octane or higher as soon as possible. Otherwise, you might damage your engine. If you are using gasoline rated at 87 octane or higher and you hear heavy knocking, your engine needs service.
If your vehicle has the 4.4L V8 engine (VIN Code D), use premium unleaded gasoline with a posted octane rating of 91 or higher. For best performance, use premium unleaded gasoline with a posted octane rating of 93. In an emergency, you can use regular unleaded gasoline with an octane rating of 87 or higher. If 87 octane fuel is used, do not perform any aggressive driving maneuvers such as wide open throttle applications. You may also hear audible spark knock during acceleration. Refill your tank with premium fuel as soon as possible to avoid damaging your engine. If you are using gasoline rated at 91 octane or higher and you hear heavy knocking, your engine needs service.
You are right...octane has nothing to do with horsepower, it has to do with REQUIREMENT, due to static and dynamic compression ratios in the engine. You will make more horsepower on higher octane fuel if you engine is smart enough to take advantage of it...our cars are.
As I stated before, the engine will retard timing if it hears knocking. You will hear it also. The engine cannot differentiale which octane rating is in the tank. Under certain conditions a lower octane fuel has a greater probability to knock, agreed on that point. But fro the most part, you will be just fine on 87. My CTS-V has always had 87 nad the car runs well, under hard acceleration, in the cold, under acceleration with the A/C blasting. I have never heard one ping nor felt any shudder. I can tell you I do drive hard, all the time. Why have a car like this if you don't flog the horses, right?
Have a nice Memorial Day guys.
Having spent the last 20 years running refineries, let me add my two cents.
The "additive" we use to increase octane is not octane, it is ethanol. We used to use MTBE but that's been outlawed to prevent ground water contamination when it leaks from gas station tanks. Ethanol has a much lower energy density than straight gasoline so it does not make more horsepower, but the computer adjusts by injecting a greater volume of fuel so you don't notice anything but lower gas milage.
Ethanol "burns more slowly" (for the chemical engineers in the crowd, this means that the flame front propogates through orderly carboxilation rather than through a more uncontrolled free radical mechanism). Bottom line is that it has less of a tendency to knock so can be run a higher compression ratios.
This thread so far has been stuck on the old school idea that compression is fixed. Add in the supercharger and the computer can now control the charge of air and fuel, so while the compression ratio remains physically fixed, the charge that is compressed into that volume is competely variable.
If knocking is limiting the computer's ability to increase the charge (boost), then higher octane fuel will increase horsepower measurably. I'm surprised to hear others say that they have never felt their engines knock. I've always felt that the computer is keeping the engine right on the edge of knocking when I stomp on it.
Do any of our tuner friends have any data from the knock sensors to tell us how close to the edge this engine gets. In any case, would be interesting to test the high octane fuel on the dyno.
The "additive" we use to increase octane is not octane, it is ethanol. We used to use MTBE but that's been outlawed to prevent ground water contamination when it leaks from gas station tanks. Ethanol has a much lower energy density than straight gasoline so it does not make more horsepower, but the computer adjusts by injecting a greater volume of fuel so you don't notice anything but lower gas milage.
Ethanol "burns more slowly" (for the chemical engineers in the crowd, this means that the flame front propogates through orderly carboxilation rather than through a more uncontrolled free radical mechanism). Bottom line is that it has less of a tendency to knock so can be run a higher compression ratios.
This thread so far has been stuck on the old school idea that compression is fixed. Add in the supercharger and the computer can now control the charge of air and fuel, so while the compression ratio remains physically fixed, the charge that is compressed into that volume is competely variable.
If knocking is limiting the computer's ability to increase the charge (boost), then higher octane fuel will increase horsepower measurably. I'm surprised to hear others say that they have never felt their engines knock. I've always felt that the computer is keeping the engine right on the edge of knocking when I stomp on it.
Do any of our tuner friends have any data from the knock sensors to tell us how close to the edge this engine gets. In any case, would be interesting to test the high octane fuel on the dyno.
Very interesting Wei,
However I don't have to be concerned about using 101 octane due to the $6.49 price tag that goes along with it! That alone says, "Not for ME!"
That's close to a $100 for a fill up.
However I don't have to be concerned about using 101 octane due to the $6.49 price tag that goes along with it! That alone says, "Not for ME!"
That's close to a $100 for a fill up.
You are partially right. I can tell you that my father used to have a 74 dart that would knock because it used to like the leaded gas. Albeit, it was carbed and not injected and didn't make more than 200 hp but I know what knocking and pinging is. The knock sensors have to be activated by a definitive knock. You would hear it for sure before the sensors triggered the timing to be retarded. They work like stability control, TC, etc. You would not say gee, I think that my car is knocking, the computer just retarded my timing, you would know.Having spent the last 20 years running refineries, let me add my two cents.
The "additive" we use to increase octane is not octane, it is ethanol. We used to use MTBE but that's been outlawed to prevent ground water contamination when it leaks from gas station tanks. Ethanol has a much lower energy density than straight gasoline so it does not make more horsepower, but the computer adjusts by injecting a greater volume of fuel so you don't notice anything but lower gas milage.
Ethanol "burns more slowly" (for the chemical engineers in the crowd, this means that the flame front propogates through orderly carboxilation rather than through a more uncontrolled free radical mechanism). Bottom line is that it has less of a tendency to knock so can be run a higher compression ratios.
This thread so far has been stuck on the old school idea that compression is fixed. Add in the supercharger and the computer can now control the charge of air and fuel, so while the compression ratio remains physically fixed, the charge that is compressed into that volume is competely variable.
If knocking is limiting the computer's ability to increase the charge (boost), then higher octane fuel will increase horsepower measurably. I'm surprised to hear others say that they have never felt their engines knock. I've always felt that the computer is keeping the engine right on the edge of knocking when I stomp on it.
Do any of our tuner friends have any data from the knock sensors to tell us how close to the edge this engine gets. In any case, would be interesting to test the high octane fuel on the dyno.
About boosting octane and horsepower, just do a google search, simple enough and you find a plethora of info that dispells the seemingly ingrained notion that we must run 95+octane in our engines. Again, I don't have a STS-V, but a CTS-V and it has only burned 87 without any problems whatsoever. If I did have the STS-V, I would undoubtedly first try to use 87 and if no problems developed, that's what I would run. Here's some tests for you guys that don't want to do a search.
http://www.europeancarweb.com/tech/0503ec_octane_boosters_tested/
http://www.bajajusa.com/High Octane.htm
MIKE BISHOP on February 13th, 2007 at 12:48 am
I have been building street engines, race engines, and alky engines with my father at his race shop since I was 11, my father recently passed away and I remember all the times when folks would ask us about weither or not they should be using the higher octane gas.
First and formost unless you have a engine that has a compresion ratio of more than 9:5:1 IT DOES NOT MATTER!
We settled this by taking two identical 2002 Z06 corvettes with nearly identical mileage, draining the gas tanks and filling one with 87 oct and the other with 103 oct, then setting the timing equal making sure both cars had the same plugs, wires, filters, oil.
We dynoed both several times, each car was nearly identical in HP and Torque.
As far as ye old leaded gas, the lead was used to cushion the valve seats in the good old days cause they didnt have hardned valve seats.
I make a nice living with the family business, so far after 35 years of serving our community the only complaints we ever get are from the guys who have us build dragster motors and they just keep wishing we told em to put more money into it.
As far as the gas argument goes there isnt even a noticible difference, on the engines we see that come into our shop for rebuilds, as a matter of fact we get people all the time who cry because they used premium gas all the time and we show them another identical engine that didnt use premium and theres no difference even in the combustion chambers.
But thats ok, all you premium junkies keep on payin the gas companys for the expensive stuff and lower those gas prices for the rest of us.
http://www.washingtonpost.com/wp-dyn/content/article/2005/08/05/AR2005080501595.html
And the grand daddy of the all, The Federal Trade Commission advises us to use the lowest octane needed to prevent knocking. Even these guys say that an occasional knock isn't harmfull and if it does happen, switch to a higher grade. http://www.ftc.gov/bcp/conline/pubs/autos/octane.shtm
Again, from my experience, the LS6 runs great on 87. Period.
You will feel the same thing with the old Buick Grand Nationals - FI loves High Octane.Why would this make a difference, unless in stock trim, the car is pulling timming due to knock?
-Chris
Keep in mind the computer uses tables for MAX timing. So, you are actually feeling the computer take advantage of that value based on no knock being reported from the sensors.
KR kicks in to subtract from that max value in case Knock is detected. KR is a rapid correction.
I'm still not on the same page with you guys. Follow me for a second. My argument is based on the following assumptions, so if they are not right, let me knowYou will feel the same thing with the old Buick Grand Nationals - FI loves High Octane.
Keep in mind the computer uses tables for MAX timing. So, you are actually feeling the computer take advantage of that value based on no knock being reported from the sensors.
KR kicks in to subtract from that max value in case Knock is detected. KR is a rapid correction.
1) In a hi-po car in OEM trim, GM is going to tune for the use of 91 Octane gas, as that is the highest octane athat is always vailable in all 50 states (FU Cali.) [A small part of me might give them the benefit of the doubt, and think that they have the maps built to go up to 93, but definately not higher than that.]
2) GM wants to put the best possible 'safe' tune on the car. By safe, I mean that they do not want to have any knock during any normal conditions (including WOT on a hot day).
With this in mind, then the 'high octane' table, that has more timing built in from the get go, will be engineered for 91(posibly 93?) octane gas, and adding higher octane isn't going to make a difference, because the car isn't pinging with the 91 octane. If it detects knock, it will retard the timing intially, and if it detects too much, it will switch to the low octane table.
I guess I could see a scenario where the high octane map is based off of 93 octane, but I couldn't see it being for anything higher. I just don't think GM would release a car to production with a car that is either 1) running around all the time on the low octane map, or 2) is having timing pulled a lot due to knock retard.
While I see if you custom tune the car to run more timing, to take advantage of the higher octane, then you;d get more power, but I just don't see it with a stock tune (I can't see where GM would release a stock tune that knocked a lot).
Please let me know where I'm wrong (preferable with some before and after dyno graphs thrown in for good measure.)
-Chris
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