Octane Requirement Question - Running USA car in South America...
07-07-2017, 10:08 PM
#1
Octane Requirement Question - Running USA car in South America...
I have a question that seems simple enough, but not sure where or how to get a definitive answer.
We have a 2009 Cup Car, with an upgraded engine at 4.0L. It was upgraded to this displacement two rebuilds ago, great car, fast car, PMNA dyno tuned engine, BBI built.
As I understand it, the car was dyno tuned at 100 octane initially, then dialed up to 104. The car currently runs 104 octane here (USA, Seattle area) at track and lapping days.
We'd like to run the car in Santiago, Chile, in the GT3 series there, but one of the regulations are that cars must run the series specified 97 octane fuel. Now without getting in to too much of a long winded discussion around RON/MON, etc....
Sorry for the Wikipedia link, but assuming the RON vs. MON vs. (R+M/2) discussion, and the fact that all the other cup cars down there run this 97 octane fuel, I'd think we would be OK/safe with the car if we retuned the ECU down to 100, or is that even not necessary?
I know we are a 4.0L motor, and running 13.5:1 compression (according to BBI), can we safely race with the Chilean 97 octane that all the other Cup cars use down there at the track?
and maybe a follow on question -- as I research and type here -- if the Chilean gas is 97 RON, which is the equivalent of 92-93 here in the USA -- are all these 996 and 997 Cup cars all running just fine on that down there? That seems like low octane for a cup car....or am I not doing the math correctly?
Thanks!
Jason
We have a 2009 Cup Car, with an upgraded engine at 4.0L. It was upgraded to this displacement two rebuilds ago, great car, fast car, PMNA dyno tuned engine, BBI built.
As I understand it, the car was dyno tuned at 100 octane initially, then dialed up to 104. The car currently runs 104 octane here (USA, Seattle area) at track and lapping days.
We'd like to run the car in Santiago, Chile, in the GT3 series there, but one of the regulations are that cars must run the series specified 97 octane fuel. Now without getting in to too much of a long winded discussion around RON/MON, etc....
Sorry for the Wikipedia link, but assuming the RON vs. MON vs. (R+M/2) discussion, and the fact that all the other cup cars down there run this 97 octane fuel, I'd think we would be OK/safe with the car if we retuned the ECU down to 100, or is that even not necessary?
I know we are a 4.0L motor, and running 13.5:1 compression (according to BBI), can we safely race with the Chilean 97 octane that all the other Cup cars use down there at the track?
and maybe a follow on question -- as I research and type here -- if the Chilean gas is 97 RON, which is the equivalent of 92-93 here in the USA -- are all these 996 and 997 Cup cars all running just fine on that down there? That seems like low octane for a cup car....or am I not doing the math correctly?
Thanks!
Jason
07-07-2017, 10:21 PM
#2
In continuing my searches and research, I see that Cup Cars are specified for 98 RON minimum.
So, why would a Cup Car race series specify 97 RON? Again, this is in Chile.
Yes, we can blend and get whatever we want, but the regulations stipulate the use of the 97 RON fuel...
Would like to know if this car can race down there or if we have to blend to make it work.
-Jason
So, why would a Cup Car race series specify 97 RON? Again, this is in Chile.
Yes, we can blend and get whatever we want, but the regulations stipulate the use of the 97 RON fuel...
Would like to know if this car can race down there or if we have to blend to make it work.
-Jason
07-08-2017, 10:44 AM
#3
Jason,
I know that car you have and it's both a beauty and a beast. I'm hardly the expert to answer your question, but I have a few thoughts. And I responded so I could hear the response of others. As I'm sure you know, the octane requirement isn't (entirely) determined by the ECU map -- it's also a function of relatively fixed engine parameters, especially the compression ratio. But it may be possible, within certain limits, to develop or obtain a map that compensates for the fixed engine parameters and allows safe running at a lower octane than 104. Is your car running a Bosch MS 3.1 system? If so, I'm not aware that such systems are "tunable" in the typical sense that a standalone system such as a Motec can be tuned. PMNA has various MS 3.1 maps for different engines, but getting ahold of one that's appropriate -- and proving that it's viable -- may be challenging. I would think that the first thing to do would be to contact the builder and tuner (BBI in this case) and discuss with Betim his thoughts on your question. To my understanding, he used to work in the dyno facility at PMNA and would be well equipped to offer good suggestions if he built and "tuned" that engine. You could also contact Tom LeClair, the shop manager at PMNA, and get his opinion. Another idea would be to do some dyno testing locally to see how it performs on 97 octane fuel. Even with no changes to anything, you could explore, under controlled circumstances, the engine performance and verify if you can "get away with" 97 octane on the current engine. For that task, I'd suggest Charles Dundon at Dundon Motorsports in Gig Harbor. He has a great dyno and really knows how to interpret the results. It's possible that, with no changes to the internals, you can run this engine at an octane that's lower than you thought. But you have to check. And of course, there's always the possibility of changing the internals, but I'm sure you're hoping to avoid that. Good luck.
Rob
I know that car you have and it's both a beauty and a beast. I'm hardly the expert to answer your question, but I have a few thoughts. And I responded so I could hear the response of others. As I'm sure you know, the octane requirement isn't (entirely) determined by the ECU map -- it's also a function of relatively fixed engine parameters, especially the compression ratio. But it may be possible, within certain limits, to develop or obtain a map that compensates for the fixed engine parameters and allows safe running at a lower octane than 104. Is your car running a Bosch MS 3.1 system? If so, I'm not aware that such systems are "tunable" in the typical sense that a standalone system such as a Motec can be tuned. PMNA has various MS 3.1 maps for different engines, but getting ahold of one that's appropriate -- and proving that it's viable -- may be challenging. I would think that the first thing to do would be to contact the builder and tuner (BBI in this case) and discuss with Betim his thoughts on your question. To my understanding, he used to work in the dyno facility at PMNA and would be well equipped to offer good suggestions if he built and "tuned" that engine. You could also contact Tom LeClair, the shop manager at PMNA, and get his opinion. Another idea would be to do some dyno testing locally to see how it performs on 97 octane fuel. Even with no changes to anything, you could explore, under controlled circumstances, the engine performance and verify if you can "get away with" 97 octane on the current engine. For that task, I'd suggest Charles Dundon at Dundon Motorsports in Gig Harbor. He has a great dyno and really knows how to interpret the results. It's possible that, with no changes to the internals, you can run this engine at an octane that's lower than you thought. But you have to check. And of course, there's always the possibility of changing the internals, but I'm sure you're hoping to avoid that. Good luck.
Rob
07-09-2017, 02:28 PM
#4
Rob -- thanks. You are 100%, correct, the source for the definitive answer is BBI and/or PMNA. I had placed calls, but it was Friday evening, so I came to the forum looking for some input.
We spoke with Betim over the weekend and have a solution. Short answer for the archives -- probably a non-issue to run the 97 RON down there, but we can also do a new map to pull back timing a touch for additional safety margin.
I'll take this offline with Betim and get this sorted to run safely. And yeah, hoping to not change the internals to adjust compression ratio, but that is of course a path as well to discuss.
Thanks again!
We spoke with Betim over the weekend and have a solution. Short answer for the archives -- probably a non-issue to run the 97 RON down there, but we can also do a new map to pull back timing a touch for additional safety margin.
I'll take this offline with Betim and get this sorted to run safely. And yeah, hoping to not change the internals to adjust compression ratio, but that is of course a path as well to discuss.
Thanks again!
09-02-2017, 02:45 AM
#6
I have a question that seems simple enough, but not sure where or how to get a definitive answer.
We have a 2009 Cup Car, with an upgraded engine at 4.0L. It was upgraded to this displacement two rebuilds ago, great car, fast car, PMNA dyno tuned engine, BBI built.
As I understand it, the car was dyno tuned at 100 octane initially, then dialed up to 104. The car currently runs 104 octane here (USA, Seattle area) at track and lapping days.
We'd like to run the car in Santiago, Chile, in the GT3 series there, but one of the regulations are that cars must run the series specified 97 octane fuel. Now without getting in to too much of a long winded discussion around RON/MON, etc....
Sorry for the Wikipedia link, but assuming the RON vs. MON vs. (R+M/2) discussion, and the fact that all the other cup cars down there run this 97 octane fuel, I'd think we would be OK/safe with the car if we retuned the ECU down to 100, or is that even not necessary?
I know we are a 4.0L motor, and running 13.5:1 compression (according to BBI), can we safely race with the Chilean 97 octane that all the other Cup cars use down there at the track?
and maybe a follow on question -- as I research and type here -- if the Chilean gas is 97 RON, which is the equivalent of 92-93 here in the USA -- are all these 996 and 997 Cup cars all running just fine on that down there? That seems like low octane for a cup car....or am I not doing the math correctly?
Thanks!
Jason
We have a 2009 Cup Car, with an upgraded engine at 4.0L. It was upgraded to this displacement two rebuilds ago, great car, fast car, PMNA dyno tuned engine, BBI built.
As I understand it, the car was dyno tuned at 100 octane initially, then dialed up to 104. The car currently runs 104 octane here (USA, Seattle area) at track and lapping days.
We'd like to run the car in Santiago, Chile, in the GT3 series there, but one of the regulations are that cars must run the series specified 97 octane fuel. Now without getting in to too much of a long winded discussion around RON/MON, etc....
Sorry for the Wikipedia link, but assuming the RON vs. MON vs. (R+M/2) discussion, and the fact that all the other cup cars down there run this 97 octane fuel, I'd think we would be OK/safe with the car if we retuned the ECU down to 100, or is that even not necessary?
I know we are a 4.0L motor, and running 13.5:1 compression (according to BBI), can we safely race with the Chilean 97 octane that all the other Cup cars use down there at the track?
and maybe a follow on question -- as I research and type here -- if the Chilean gas is 97 RON, which is the equivalent of 92-93 here in the USA -- are all these 996 and 997 Cup cars all running just fine on that down there? That seems like low octane for a cup car....or am I not doing the math correctly?
Thanks!
Jason
We have several cup cars running pump fuel, but you definitely cannot use a 100 or 104 RON map.