Fuel options on the GTS
Wess-RA
09-18-2009, 05:05 PM
Ok-I am pretty sure I'll get beat up over this one with the GTS guys. I know the manual makes a statement that anything but 110 leaded is not recommended. But then they go ahead and give jetting/tuning guides for Sunoco 94 octane and 110LL Aviation fuel. So when I was at the track I got sticker shock from the $8.00/gal price tag for 110 leaded. I used to think aviation 110 LL was expensive for my plane but now at $4.50 it is a downright bargain. My very experienced mechanic (chief mechanic for Trans Am series for many years) says that pump gas is crap and has "all kinds of stuff" in it. He is also a pilot and uses the 110 LL in his plane even though it is older and is certified for pump gas. (because it is crap). Since our compression is only 10.5:1 he feels the 110LL is perfectly fine to use. The beauty is that all 3 tracks I frequent are within minutes of an airport.
Please chime in guys! What do you think?
Please chime in guys! What do you think?
NZGTRA17
09-18-2009, 07:07 PM
Ok-I am pretty sure I'll get beat up over this one with the GTS guys. I know the manual makes a statement that anything but 110 leaded is not recommended. But then they go ahead and give jetting/tuning guides for Sunoco 94 octane and 110LL Aviation fuel. So when I was at the track I got sticker shock from the $8.00/gal price tag for 110 leaded. I used to think aviation 110 LL was expensive for my plane but now at $4.50 it is a downright bargain. My very experienced mechanic (chief mechanic for Trans Am series for many years) says that pump gas is crap and has "all kinds of stuff" in it. He is also a pilot and uses the 110 LL in his plane even though it is older and is certified for pump gas. (because it is crap). Since our compression is only 10.5:1 he feels the 110LL is perfectly fine to use. The beauty is that all 3 tracks I frequent are within minutes of an airport.
Please chime in guys! What do you think?
Uwe, I know the octane ratings between NZ and States are not directly comparable but here goes. I have used our 100 octane Aviation gas here for years in race engines up to 11.2 : 1 comp. Most of these engines were iron headed not aluminium so you can possibly get away with a smidge more comp than 11.2 on this octane with ally heads.
We have much the same fuel as the Aviation 100 octane also pedalled as Motor Race fuel. Many try to say that the Aviation fuel is no good and that the Race gas is the way to go. This is absolute BS. The aviation fuel will have gone through much more rigorous quality control and will be "fresher". I actually suspect that the Motor Race fuel is date expired aviation fuel............no I am not a conspiracy theorist!!
I currently build for and use 98 octane premium unleaded pump gas. Main reasons are cost and availability. I will try to run this in the 347 at 10.5 comp but will confirm suitability by dyno testing and checking optimal timing Vs detonation by having a det set mounted to the car for all tuning runs. In my view this is the only way to really know, dyno with a det set while playing with fuel crves and timing curves to find out where the sweet spot and the limit are. If your fuel wont let you get to the sweet spot with the set up you have, more octane required.
Kel.
Please chime in guys! What do you think?
Uwe, I know the octane ratings between NZ and States are not directly comparable but here goes. I have used our 100 octane Aviation gas here for years in race engines up to 11.2 : 1 comp. Most of these engines were iron headed not aluminium so you can possibly get away with a smidge more comp than 11.2 on this octane with ally heads.
We have much the same fuel as the Aviation 100 octane also pedalled as Motor Race fuel. Many try to say that the Aviation fuel is no good and that the Race gas is the way to go. This is absolute BS. The aviation fuel will have gone through much more rigorous quality control and will be "fresher". I actually suspect that the Motor Race fuel is date expired aviation fuel............no I am not a conspiracy theorist!!
I currently build for and use 98 octane premium unleaded pump gas. Main reasons are cost and availability. I will try to run this in the 347 at 10.5 comp but will confirm suitability by dyno testing and checking optimal timing Vs detonation by having a det set mounted to the car for all tuning runs. In my view this is the only way to really know, dyno with a det set while playing with fuel crves and timing curves to find out where the sweet spot and the limit are. If your fuel wont let you get to the sweet spot with the set up you have, more octane required.
Kel.
Wess-RA
09-18-2009, 08:44 PM
Kel, What color is the 110 leaded in NZ; here it is purple. Interesting on your theory on the 100L racing fuel being outdated Avgas. Ive' never pumped it into a bottle; is it light blue as is the Universal color for 100LL Avgas? I agree that the Avgas is manufactured/controlled to the highest standard.
Your thought on dyno being a determining factor is a very good one. I have never dynoed my car; it may be worth it to have both fuels on hand. My airplane has total engine monitoring. It checks each cylinder for Cylinder Head Temp. and EGT, also oil temp, turbo inlet temp, and fuel flow. Is it worth it in your opinion, to permanently mount your det gage? I considered mounting an EGT but figured it wasn't worth it as I barely have the time to glance at my water temp gage while racing.
Probably a better subject for another thread, but I recall Kevin installed a fuel flow totalizer. Sounds like a good idea to be able to get away from wooden dip sticks and calculations. Hey its not like Panoz engineered these cars for weight reduction. What would that weigh 1/4#? Just eat one less hamburger before racing. :smile:
Your thought on dyno being a determining factor is a very good one. I have never dynoed my car; it may be worth it to have both fuels on hand. My airplane has total engine monitoring. It checks each cylinder for Cylinder Head Temp. and EGT, also oil temp, turbo inlet temp, and fuel flow. Is it worth it in your opinion, to permanently mount your det gage? I considered mounting an EGT but figured it wasn't worth it as I barely have the time to glance at my water temp gage while racing.
Probably a better subject for another thread, but I recall Kevin installed a fuel flow totalizer. Sounds like a good idea to be able to get away from wooden dip sticks and calculations. Hey its not like Panoz engineered these cars for weight reduction. What would that weigh 1/4#? Just eat one less hamburger before racing. :smile:
panozracing
09-18-2009, 09:14 PM
Hey Uwe, how fast is that factory 5 GTM that I see on your avatar pic?
they look AWESOME!!!!
My engine builder told me to absolutely run 112 LEADED fuel in our race engine. Cheap insurance....
they look AWESOME!!!!
My engine builder told me to absolutely run 112 LEADED fuel in our race engine. Cheap insurance....
Wess-RA
09-18-2009, 09:31 PM
This Factory Five GTM is absolutely awesome. The driver (David Ray) can really haul the mail with it. It is really modified (weird term considering it is owner built). It's set up as a center cockpit car. Check this out, this is the actual car.
http://www.factoryfive.com/gtm/gallery/pdg/gallery.html
You mean I didn't give the illusion of being out in front of him?:smile:
http://www.factoryfive.com/gtm/gallery/pdg/gallery.html
You mean I didn't give the illusion of being out in front of him?:smile:
Cobra4B
09-18-2009, 10:09 PM
Uwe any more pics of the car? Looks good! Not sure why you have to go nuts w/ fuel. I mean my Corvette is 10.5:1 stock and it runs just fine on 93 pump gas even in major heat w/o any detonation. I used to put a splash of 100 octane sunoco in at VIR in the hot summer events.
W/ the panoz we tuned it on 93 octane pump gas, but mix it w/ 100 during the summer events.
There's nothing special about the 351.... I guess I just don't see the need to run the fancy gas.
W/ the panoz we tuned it on 93 octane pump gas, but mix it w/ 100 during the summer events.
There's nothing special about the 351.... I guess I just don't see the need to run the fancy gas.
boothkc
09-18-2009, 10:21 PM
Uwe,
as a fellow pilot I can tell you your super mechanic/pilot is alarmingly wrong! Not sure he knows his flaps from a shifter. Wouldn't fly with him.
Aviation fuel available at alll our local airports is 100LL (NOT 110!!) and is dyed blue for clear identification. There are no local airports in Norcal that sell 110 fuel... The only avgas available in the US is 100LL (low lead) and in some locations 130 (yummy if you have a hp P51).
So 100LL is about $4.79/gal at Livermore and 110 leaded is about $7.50/gal at the track (which by the way helps to support the track and the SCCA etc.).
Given limited race use and pretty high lead levels in avgas I don't think you'd screw up your valve seats but why give up the HP and detune your motor for a few bucks??? This racing gig is pretty expensive and gas is my least significant part. I burn about 8gal/ race...so assuming a practice, qual, race you are looking at a delta of <$75.
Hope this helps,
Kevin
as a fellow pilot I can tell you your super mechanic/pilot is alarmingly wrong! Not sure he knows his flaps from a shifter. Wouldn't fly with him.
Aviation fuel available at alll our local airports is 100LL (NOT 110!!) and is dyed blue for clear identification. There are no local airports in Norcal that sell 110 fuel... The only avgas available in the US is 100LL (low lead) and in some locations 130 (yummy if you have a hp P51).
So 100LL is about $4.79/gal at Livermore and 110 leaded is about $7.50/gal at the track (which by the way helps to support the track and the SCCA etc.).
Given limited race use and pretty high lead levels in avgas I don't think you'd screw up your valve seats but why give up the HP and detune your motor for a few bucks??? This racing gig is pretty expensive and gas is my least significant part. I burn about 8gal/ race...so assuming a practice, qual, race you are looking at a delta of <$75.
Hope this helps,
Kevin
NZGTRA17
09-19-2009, 03:33 PM
Kel, What color is the 110 leaded in NZ; here it is purple. Interesting on your theory on the 100L racing fuel being outdated Avgas. Ive' never pumped it into a bottle; is it light blue as is the Universal color for 100LL Avgas? I agree that the Avgas is manufactured/controlled to the highest standard.
Your thought on dyno being a determining factor is a very good one. I have never dynoed my car; it may be worth it to have both fuels on hand. My airplane has total engine monitoring. It checks each cylinder for Cylinder Head Temp. and EGT, also oil temp, turbo inlet temp, and fuel flow. Is it worth it in your opinion, to permanently mount your det gage? I considered mounting an EGT but figured it wasn't worth it as I barely have the time to glance at my water temp gage while racing.
Probably a better subject for another thread, but I recall Kevin installed a fuel flow totalizer. Sounds like a good idea to be able to get away from wooden dip sticks and calculations. Hey its not like Panoz engineered these cars for weight reduction. What would that weigh 1/4#? Just eat one less hamburger before racing. :smile:
Uwe, both our Avgas and Racing Fuel (both BP products) are coloured green and are both 100 octane. The MSDS sheet tech info for both products are identical (which is why I have previously believed that they are the same product).
There are a lot of assumptions made about more octane equalling more power. This is not necessarily true. The additional octane will enable you to run higher compression without detonation and this will produce more power. Running higher octane than required will only provide a safety margin where conditions change (and you may otherwise be in the curve for detonation with your engine config).
I have had engine builders tell me that they have seen some engines lose power when swapped from a lower octane fuel to a higher octane fuel. As far as I can work out this is due to differences in flame travel between fuels and the particular characteristics of some combustion chambers. This is why I beleive that dynoing is the way to determine what fuel best suits the setup of your engine.
If I had lots of spare racing cash Uwe I would fit a fuel ratio monitoring setup in the car and use this to tune the car for differing track elevations and atmospheric conditions. A good example of the requirement for this are the temp/altitude/jetting graphs in the GTS manual. I know when I fitted the cold air system to my car it took an additional 2 jet sizes in the rears. You can get det setups for permanent fitment Uwe but I have always thought I would set up on the dyno, know what airfuel ratio range was safe, and then use an onboard ratio setup to monitor and change jetting as/if required.
Kel.
Your thought on dyno being a determining factor is a very good one. I have never dynoed my car; it may be worth it to have both fuels on hand. My airplane has total engine monitoring. It checks each cylinder for Cylinder Head Temp. and EGT, also oil temp, turbo inlet temp, and fuel flow. Is it worth it in your opinion, to permanently mount your det gage? I considered mounting an EGT but figured it wasn't worth it as I barely have the time to glance at my water temp gage while racing.
Probably a better subject for another thread, but I recall Kevin installed a fuel flow totalizer. Sounds like a good idea to be able to get away from wooden dip sticks and calculations. Hey its not like Panoz engineered these cars for weight reduction. What would that weigh 1/4#? Just eat one less hamburger before racing. :smile:
Uwe, both our Avgas and Racing Fuel (both BP products) are coloured green and are both 100 octane. The MSDS sheet tech info for both products are identical (which is why I have previously believed that they are the same product).
There are a lot of assumptions made about more octane equalling more power. This is not necessarily true. The additional octane will enable you to run higher compression without detonation and this will produce more power. Running higher octane than required will only provide a safety margin where conditions change (and you may otherwise be in the curve for detonation with your engine config).
I have had engine builders tell me that they have seen some engines lose power when swapped from a lower octane fuel to a higher octane fuel. As far as I can work out this is due to differences in flame travel between fuels and the particular characteristics of some combustion chambers. This is why I beleive that dynoing is the way to determine what fuel best suits the setup of your engine.
If I had lots of spare racing cash Uwe I would fit a fuel ratio monitoring setup in the car and use this to tune the car for differing track elevations and atmospheric conditions. A good example of the requirement for this are the temp/altitude/jetting graphs in the GTS manual. I know when I fitted the cold air system to my car it took an additional 2 jet sizes in the rears. You can get det setups for permanent fitment Uwe but I have always thought I would set up on the dyno, know what airfuel ratio range was safe, and then use an onboard ratio setup to monitor and change jetting as/if required.
Kel.
boothkc
09-20-2009, 10:52 AM
Here is a link to help ID and compare AV gas: http://purvisbros.com/afi/moderncivavgas.htm
Av gas is dyed blue (or green) so that when sample for contamination (eg. water) its color can be verified. The main reason for this is to help confirm that Jet A (essentially diesel fuel/kerosene) hasn't been inadvertantly added to a piston engines fuel tank. Prior to each flight the pilot will sump a sample from each tank (5 sump points on my Cirrus) and inspect it. This happens a few times a year with the plane running normally until the line fuel is used and the mix kills the engine a few hundred feet above the ground.
A well publicsized case happend last year in a new turbo Cirrus SR22. There is a large "Turbo" sticker on the side and the fuel guy thought it was a turbine (jet) and filled it with Jet A......4 people dead.
So either blue or green AV gas around the world tends to be 100 octane and has lead (for now!) and should run fine in our cars provided the timing is retarded enought to prevent detonation and engine damage.
If you want to run 100 I'd have the care dyno tuned and you should be fine. I suspect the 110 rec from PAD was to cover their butts and all lots of margin for detination, but it also allows you to safely push the timing and hp up a bit.
Remember street engines don't see the endurance and sustained loads that road race cars do.
Kevin
GTS/GTRA
Cirrus SR22
Av gas is dyed blue (or green) so that when sample for contamination (eg. water) its color can be verified. The main reason for this is to help confirm that Jet A (essentially diesel fuel/kerosene) hasn't been inadvertantly added to a piston engines fuel tank. Prior to each flight the pilot will sump a sample from each tank (5 sump points on my Cirrus) and inspect it. This happens a few times a year with the plane running normally until the line fuel is used and the mix kills the engine a few hundred feet above the ground.
A well publicsized case happend last year in a new turbo Cirrus SR22. There is a large "Turbo" sticker on the side and the fuel guy thought it was a turbine (jet) and filled it with Jet A......4 people dead.
So either blue or green AV gas around the world tends to be 100 octane and has lead (for now!) and should run fine in our cars provided the timing is retarded enought to prevent detonation and engine damage.
If you want to run 100 I'd have the care dyno tuned and you should be fine. I suspect the 110 rec from PAD was to cover their butts and all lots of margin for detination, but it also allows you to safely push the timing and hp up a bit.
Remember street engines don't see the endurance and sustained loads that road race cars do.
Kevin
GTS/GTRA
Cirrus SR22
Wess-RA
09-28-2009, 12:50 PM
Kevin, It was my typo not the mechanics knowledge on the 110LL vs 100LL for Avgas. I had to go back in the thread to see why you made the comment. (its rough getting old) I'm a T210 owner and am up on all the sampling reasons/requirements and color coding.
Based upon all the comments I think a trip to the dyno is a good idea regardless. Thanks for the avgas specs, do you have any specs for the 110 leaded race fuel? Kel makes very good points. I am really interested in getting some hard numbers on which may actually be better. Do you know of a good dyno tune shop in the area. How is the guy that is located at T-hill? I'm going to be there on Friday. (They are running 7 x 20 min. sessions in one day, not bad eh!) My car didn't come with any dyno results.
I had to reread this to make sure I didn't make the same typo this time again-sometimes I move too fast. :screwy:
Based upon all the comments I think a trip to the dyno is a good idea regardless. Thanks for the avgas specs, do you have any specs for the 110 leaded race fuel? Kel makes very good points. I am really interested in getting some hard numbers on which may actually be better. Do you know of a good dyno tune shop in the area. How is the guy that is located at T-hill? I'm going to be there on Friday. (They are running 7 x 20 min. sessions in one day, not bad eh!) My car didn't come with any dyno results.
I had to reread this to make sure I didn't make the same typo this time again-sometimes I move too fast. :screwy:
boothkc
09-28-2009, 03:14 PM
Uwe,
I have a SR22 at KLVK....we should meet for a $100 burger!!!
I had the guy at Thunderhill dyno the GTS and GTRA last year for curiosity. He didn't do any tuning, though.
I don't know if he has any Holly jets etc and can make any adjustments.
These cars make lots of noise on the Dyno!!!
Have fun.
Kevin
I have a SR22 at KLVK....we should meet for a $100 burger!!!
I had the guy at Thunderhill dyno the GTS and GTRA last year for curiosity. He didn't do any tuning, though.
I don't know if he has any Holly jets etc and can make any adjustments.
These cars make lots of noise on the Dyno!!!
Have fun.
Kevin
Wess-RA
09-29-2009, 02:24 PM
Its more like a $250 burger these days isn't it. Hey for the 1st time flying feels cheap due to the comparison with the expense of racing cars.
I have the complete jet kit so I'll see if he can pull of the dial in.
I'll let you know the results.
I have the complete jet kit so I'll see if he can pull of the dial in.
I'll let you know the results.
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