Testing at Thunderhill
04-04-2011, 04:34 AM
#31
acceleration = ((torque x RPM) / 5252) / (mass x velocity)
Wait, you actually disagree with VR when he says that a big V8 with a lot of torque will accelerate faster than a higher revving engine of equal power but less torque?
Really?
Scott
04-04-2011, 08:59 AM
#32
Rennlist Member
Here is another formula for acceleration:
acceleration = ((torque x RPM) / 5252) / (mass x velocity)
Wait, you actually disagree with VR when he says that a big V8 with a lot of torque will accelerate faster than a higher revving engine of equal power but less torque?
Really?
Scott
acceleration = ((torque x RPM) / 5252) / (mass x velocity)
Wait, you actually disagree with VR when he says that a big V8 with a lot of torque will accelerate faster than a higher revving engine of equal power but less torque?
Really?
Scott
Wanna watch his head explode? Check this out:
"Holding a gear too long causes higher G values after the shift. Adjust shift RPM accordlingly, unless the track dictates compromises to avoid shifting in corners, etc. Find the shift RPM that reduces the difference in G's before and after the shift to less than .02. "
-Buddy Fey, the legendary Grand Am DP, ALMS, etc. race engineer
04-04-2011, 01:06 PM
#33
Rennlist Member
Thread Starter
VR Dave is right, my head will explode by this reponse! Really, you dont understand what I said?
I dont think VR really believes what you wrote. Ill let you in on a little secret. He finds a condition where the physics dont lie, but where application of the physics doesnt work. Like , coming out of the turn or in a turn, where traction is limited or you dont want to upset the car. then, he is absolutely right where you wouldnt want to be at max power (or max acceleration capablity, or want to upset the car for a shift)
NOW, to answer your question/ or respond to the comment, Ill put it as clearly and politely as I can, ok?
I said it, and so did you ....... EQUAL HP. that not only means equal Peak hp, but equal HP at the point on the track in question. so, if you EVER coming out of a turn, at the same HP as someone else, you will be able to accelerate EXACTLY the same as the other guy EVEN THOUGH he has 2-3x more torque at the engine. Why? because acceleration= power/(mass x velocity). More specifically, at that same power, the rear wheel torque, as multiplied by the gear ratios to achieve that same speed will be the SAME!!!
Does that make sense. VR, do you disagree??
I dont post my ideas on this topic, I just bring up the facts. How you interpret the facts is your own choice, but anywhere on the track, if you ever have the same HP as your competitor at that same speed, you will accelerate exactly the same (Ceterus Paribus) . And, this is regardless of what engine torque you produce.
example. a 438rwhp porsche RSR F-6 and a 440rwhp Viper V10 (300rwt vs 500rwt)
or the 928 V8 vs the M3 euro 3.2 I-6 ( 290rwhp vs 285rwhp, 300rw torque vs 200wr torque )
Actually, the porsche vs BMW is the best example of this in that the BMW has the advantage ANYWHERE on the track because it has more power anywhere the track, but never has greater engine power too.
I dont think VR really believes what you wrote. Ill let you in on a little secret. He finds a condition where the physics dont lie, but where application of the physics doesnt work. Like , coming out of the turn or in a turn, where traction is limited or you dont want to upset the car. then, he is absolutely right where you wouldnt want to be at max power (or max acceleration capablity, or want to upset the car for a shift)
NOW, to answer your question/ or respond to the comment, Ill put it as clearly and politely as I can, ok?
I said it, and so did you ....... EQUAL HP. that not only means equal Peak hp, but equal HP at the point on the track in question. so, if you EVER coming out of a turn, at the same HP as someone else, you will be able to accelerate EXACTLY the same as the other guy EVEN THOUGH he has 2-3x more torque at the engine. Why? because acceleration= power/(mass x velocity). More specifically, at that same power, the rear wheel torque, as multiplied by the gear ratios to achieve that same speed will be the SAME!!!
Does that make sense. VR, do you disagree??
I dont post my ideas on this topic, I just bring up the facts. How you interpret the facts is your own choice, but anywhere on the track, if you ever have the same HP as your competitor at that same speed, you will accelerate exactly the same (Ceterus Paribus) . And, this is regardless of what engine torque you produce.
example. a 438rwhp porsche RSR F-6 and a 440rwhp Viper V10 (300rwt vs 500rwt)
or the 928 V8 vs the M3 euro 3.2 I-6 ( 290rwhp vs 285rwhp, 300rw torque vs 200wr torque )
Actually, the porsche vs BMW is the best example of this in that the BMW has the advantage ANYWHERE on the track because it has more power anywhere the track, but never has greater engine power too.
Here is another formula for acceleration:
acceleration = ((torque x RPM) / 5252) / (mass x velocity)
Wait, you actually disagree with VR when he says that a big V8 with a lot of torque will accelerate faster than a higher revving engine of equal power but less torque?
Really?
Scott
acceleration = ((torque x RPM) / 5252) / (mass x velocity)
Wait, you actually disagree with VR when he says that a big V8 with a lot of torque will accelerate faster than a higher revving engine of equal power but less torque?
Really?
Scott
Last edited by mark kibort; 04-04-2011 at 01:58 PM.
04-04-2011, 01:18 PM
#34
Rennlist Member
Thread Starter
Scott, let it go. He's on a roll. As I said, I hope he never changes. This sort of...material....is priceless.
Wanna watch his head explode? Check this out:
"Holding a gear too long causes higher G values after the shift. Adjust shift RPM accordlingly, unless the track dictates compromises to avoid shifting in corners, etc. Find the shift RPM that reduces the difference in G's before and after the shift to less than .02. "
-Buddy Fey, the legendary Grand Am DP, ALMS, etc. race engineer
Wanna watch his head explode? Check this out:
"Holding a gear too long causes higher G values after the shift. Adjust shift RPM accordlingly, unless the track dictates compromises to avoid shifting in corners, etc. Find the shift RPM that reduces the difference in G's before and after the shift to less than .02. "
-Buddy Fey, the legendary Grand Am DP, ALMS, etc. race engineer
Buddy Fey is absolutely right, because he is quoting basic physics here and applying it to a general circumstance where redline might not be appropriate. I provided several car examples where redline is not the best place to shift. I actually owned one. and by understanding these concepts, early on, I was able to adapt shift points to maximize acceleration in any gear.
If I may, I will explain in layman's term what Buddy is saying. " if you have a engine that has a hp curve where you shift well beyond the hp point, where the nexg gear shift point hp is higher, you shifted too late. you want to maximize hp, so shift a point, capable by your engine and conditinos where the post shift is never higher than the preshift point." what he also says may never be applicable to street gear boxes and engiens. "reduce G gaps by 2%" ? some engines make near 10% more power preshift, than post and will never get to 2%. you are taking what he is saying pretty far out of context ( laymens term again. context= "the way it was intended to be used".)
the example of the 993 (CORRECTION:should read 996 as shown by the dyno runs below.
) you posted and dyno runs we all had posted, showed that redline was the point of maxmim application of the hp available. shifting , the VR, "300 rpm" earlier, was going to cost your student near 20-30hp for the time he spent in that rpm speed range. Thats not the fastest way down a straight where none of the conditional factors are present.
Last edited by mark kibort; 04-04-2011 at 04:29 PM.
04-04-2011, 01:23 PM
#35
Rennlist Member
Does anyone find Mark's condescending "I know better than you all, since no one but me understands or comprehends basic concepts...so let me explain it to you mouthbreathing peons" attitude to be priceless entertainment? Combined with 20,000 words of circular verbosity, it's full of win! Thanks, Mark! Again, please do not ever change!!! 
04-04-2011, 01:24 PM
#36
Rennlist Member
Thread Starter
Scott,
I dont know if you were around for the shift vs HP vs acceleration debate.
this is a real quick example.
condtions. usuing the standard gear shift spacing of 72% (meaning post shift rpm is 72% of the preshift RPM)
Here is a BMW vs porsche V8. the V8 clearly has more torque and a little more power. Is there any point on the track, any track, any turn where the V8 torquey 928 wouldnt be at a disadvantage . (i.e. off a turn, down a straight, behind the pacecar, etc. )
If there is, I have been all wong on the topic.
Its all about maximizing Hp-seconds, VR. The more power you can apply to the wheels at any and all times, the faster you will be! (providing you can put it down to the ground out control or traction issues. )
below, the bmw, 928, and garrett's 996 hp dyno runs from the "shift point discussion".
I dont know if you were around for the shift vs HP vs acceleration debate.
this is a real quick example.
condtions. usuing the standard gear shift spacing of 72% (meaning post shift rpm is 72% of the preshift RPM)
Here is a BMW vs porsche V8. the V8 clearly has more torque and a little more power. Is there any point on the track, any track, any turn where the V8 torquey 928 wouldnt be at a disadvantage . (i.e. off a turn, down a straight, behind the pacecar, etc.
)If there is, I have been all wong on the topic.
Its all about maximizing Hp-seconds, VR. The more power you can apply to the wheels at any and all times, the faster you will be! (providing you can put it down to the ground out control or traction issues.
)below, the bmw, 928, and garrett's 996 hp dyno runs from the "shift point discussion".
04-04-2011, 01:39 PM
#37
Rennlist Member
Thread Starter
your questions are condecending Dave, and you know it. part of this is in fun, but both scot and you have challenged me to prove the point.
you even quote Buddy for the 2% shift differntial in power, yet your advice in the other thread was to " Shift 300rpm early, because the engine is just making noise at that point". DAVE, do you listen to yourself. do you even remember posting this?? You wont believe me, but you listen to Buddy , but still dont get it. you quoted 7% post shift HP loss by shifting early!! I quoted near 0%. Im following the direction of a Buddy, because it is simple math, and thats why Buddy follows it too. Its pretty simple knoweledge but you fight me every step of the way.Its not "no one but me" VR, its only you and a couple of others. Most get it, and dont want to get involved. your shift point clinic was a great example of this. VR, listen, you dont understand if what you write is really what you think!
hey, as far as the long posts. I try and make them as clear as possible as to not leave any loop holes for you to shoot through.
now, if i was having a normal conversation, it would just be "power dictates acceleration at any vehicle speed, regardless of engine torque." and leave it at that. For shift points, , it would be , "shift to maximize HP, regardless of max hp and up until redline if required.
that might be simple enough for you , right? Hey, you can use that in your next professional coaching engagement if they ask you where to shift. BUT, you better ask for a set of HP curves and their gear ratios! !
you even quote Buddy for the 2% shift differntial in power, yet your advice in the other thread was to " Shift 300rpm early, because the engine is just making noise at that point". DAVE, do you listen to yourself. do you even remember posting this?? You wont believe me, but you listen to Buddy , but still dont get it. you quoted 7% post shift HP loss by shifting early!! I quoted near 0%. Im following the direction of a Buddy, because it is simple math, and thats why Buddy follows it too. Its pretty simple knoweledge but you fight me every step of the way.Its not "no one but me" VR, its only you and a couple of others. Most get it, and dont want to get involved. your shift point clinic was a great example of this. VR, listen, you dont understand if what you write is really what you think!
hey, as far as the long posts. I try and make them as clear as possible as to not leave any loop holes for you to shoot through.
now, if i was having a normal conversation, it would just be "power dictates acceleration at any vehicle speed, regardless of engine torque." and leave it at that. For shift points, , it would be , "shift to maximize HP, regardless of max hp and up until redline if required.
that might be simple enough for you , right? Hey, you can use that in your next professional coaching engagement if they ask you where to shift. BUT, you better ask for a set of HP curves and their gear ratios! !
Does anyone find Mark's condescending "I know better than you all, since no one but me understands or comprehends basic concepts...so let me explain it to you mouthbreathing peons" attitude to be priceless entertainment? Combined with 20,000 words of circular verbosity, it's full of win! Thanks, Mark! Again, please do not ever change!!!
04-04-2011, 01:54 PM
#39
Rennlist Member
Thread Starter
what are "E automatics or semi".
Sounds like you are in! lets get that thing cleaned up so its not an embarrasment and start running with us. NO you dont need a fuel cell. our plastic tank gets a waver.
write me an email and Ill get the official word to Darrell who is running the series. do you want to run this weekend?? you can fight with Miki in the mustang challenge like car. she is running in the 207 range.
and you get to run against all the other Groupe3 cars where you will do really welll against them!
Sounds like you are in! lets get that thing cleaned up so its not an embarrasment and start running with us. NO you dont need a fuel cell. our plastic tank gets a waver.
write me an email and Ill get the official word to Darrell who is running the series. do you want to run this weekend?? you can fight with Miki in the mustang challenge like car. she is running in the 207 range.
and you get to run against all the other Groupe3 cars where you will do really welll against them!
Interesting set of rules:
"E. Automatic and semi-automatic transmissions will be allowed
only on a case by case basis if the driver can show cause."
Hmm...I wonder if an acceptable "cause" is I can't afford to convert to an automatic!!!!!! If that doesn't work I'll try "the manuals break too often"...that should be good cause!.. I like to call it "poor mans sequential"
The other bummer is it looks like fuel cells are required!!!!!
"E. Automatic and semi-automatic transmissions will be allowed
only on a case by case basis if the driver can show cause."
Hmm...I wonder if an acceptable "cause" is I can't afford to convert to an automatic!!!!!! If that doesn't work I'll try "the manuals break too often"...that should be good cause!.. I like to call it "poor mans sequential"
The other bummer is it looks like fuel cells are required!!!!!
04-04-2011, 01:56 PM
#40
Rennlist Member
Thread Starter
Hey, Matt,
Did you think my response to Scott was condecending? he asked a pointed question of whether I believe ....... etc, and I posted a polite response. the thing VR and I have going is a little different.
Did you think my response to Scott was condecending? he asked a pointed question of whether I believe ....... etc, and I posted a polite response. the thing VR and I have going is a little different.
04-04-2011, 03:27 PM
#41
Rennlist Member
04-04-2011, 03:49 PM
#42
Rennlist Member
Thread Starter
Dave,
Play nice . You and I are on double secret probation!
i know you agree with what I'm saying. dont you ?? If you dont, please let me know. really, i want to know if this is just friendly bantering, or if there is a disconnect.
What part of what I have posted do you not agree with?
Take the curves I just posted of two common race car engine profiles and use Buddy's direction, and your own "rpms up top are just noise in the 993", and let me know if the resultant shift points are not optimized with my descriptions.
MK
BTW Sunday actualy brought up something on the other site that will help find shift points. start at redline and draw a straight line with the RPM drop for any gear. if you cant draw a straight line and hit the rpm drop point, shift at redline. If you can, (rare), then back off the RPM til it fits.
Play nice . You and I are on double secret probation!
i know you agree with what I'm saying. dont you ?? If you dont, please let me know. really, i want to know if this is just friendly bantering, or if there is a disconnect.
What part of what I have posted do you not agree with?
Take the curves I just posted of two common race car engine profiles and use Buddy's direction, and your own "rpms up top are just noise in the 993", and let me know if the resultant shift points are not optimized with my descriptions.
MK
BTW Sunday actualy brought up something on the other site that will help find shift points. start at redline and draw a straight line with the RPM drop for any gear. if you cant draw a straight line and hit the rpm drop point, shift at redline. If you can, (rare), then back off the RPM til it fits.
04-04-2011, 03:51 PM
#43
Admin
Lifetime Rennlist
Member
Lifetime Rennlist
Member
04-04-2011, 03:56 PM
#44
Rennlist Member
Mark, I am not going to resuscitate an old debate that you lost. There is no point, nor anything good that can come from it. Besides, it was a 996, which, in case you don't know, is very different from a 993.
04-04-2011, 04:02 PM
#45
Rennlist Member
