A8 vs M7
Le Mans Master
Joined: May 2000
Posts: 8,729
Likes: 1,508
From: Redmond WA
The A8 certainly requires no skills! The M7 even in a roll requires more skill. Don't about talk skills in an Auto! 
The roll race proves the faster car. You pull in a roll race your not getting run down like a low hp Auto.
The 1/4 is a traction contest controlled by the traction in your 60ft that's why it's lame. The roll race is a truer contest of speed.
The part that most annoys me is that 95% of the time one car jumps and seems to win. At least from the videos. Remember at 90mph a quarter of a second is a BIG distance. With a big power delta the jumper will still get run down, but with close cars it's often too much to overcome.
At 70mph you cover over 102 feet per second. A quarter second jump is over 25 feet of advantage, and a lot of those "races" are closer than that and have a bigger jump. (I know the -delta- in speeds is not 70 mph, I'm just talking about leaving early).
Thread Starter
Team Owner
Joined: Mar 2005
Posts: 20,933
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From: salem OR
Roll race is no different than a dyno pull. No driver involvement, really only useful in 1:1 gearing to prove anything, generally boring, and sometimes something goes spectacularly wrong.
The part that most annoys me is that 95% of the time one car jumps and seems to win. At least from the videos. Remember at 90mph a quarter of a second is a BIG distance. With a big power delta the jumper will still get run down, but with close cars it's often too much to overcome.
At 70mph you cover over 102 feet per second. A quarter second jump is over 25 feet of advantage, and a lot of those "races" are closer than that and have a bigger jump. (I know the -delta- in speeds is not 70 mph, I'm just talking about leaving early).
The part that most annoys me is that 95% of the time one car jumps and seems to win. At least from the videos. Remember at 90mph a quarter of a second is a BIG distance. With a big power delta the jumper will still get run down, but with close cars it's often too much to overcome.
At 70mph you cover over 102 feet per second. A quarter second jump is over 25 feet of advantage, and a lot of those "races" are closer than that and have a bigger jump. (I know the -delta- in speeds is not 70 mph, I'm just talking about leaving early).
Even 2-3 tenths off the line is getting left in a 1/4 race. Because 1 is sitting still. So head starts are part of the race in the 1/4. Roll racing is much more even starting with your car doing the work
Scraping the splitter.
Joined: Jun 2005
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St. Jude Donor '13-'14-'15
Roll race is no different than a dyno pull. No driver involvement, really only useful in 1:1 gearing to prove anything, generally boring, and sometimes something goes spectacularly wrong.
The part that most annoys me is that 95% of the time one car jumps and seems to win. At least from the videos. Remember at 90mph a quarter of a second is a BIG distance. With a big power delta the jumper will still get run down, but with close cars it's often too much to overcome.
At 70mph you cover over 102 feet per second. A quarter second jump is over 25 feet of advantage, and a lot of those "races" are closer than that and have a bigger jump. (I know the -delta- in speeds is not 70 mph, I'm just talking about leaving early).
The part that most annoys me is that 95% of the time one car jumps and seems to win. At least from the videos. Remember at 90mph a quarter of a second is a BIG distance. With a big power delta the jumper will still get run down, but with close cars it's often too much to overcome.
At 70mph you cover over 102 feet per second. A quarter second jump is over 25 feet of advantage, and a lot of those "races" are closer than that and have a bigger jump. (I know the -delta- in speeds is not 70 mph, I'm just talking about leaving early).
A .3-.4 interval really isn't much at all. However, cars at this level will accelerate 4-5 mph in that interval. So if we run from 60 mph and I jump, in ~.3-.4 seconds I already have a 5 mph advantage before you even go WOT and am pulling. By the time you go WOT, ~.3-.4 seconds later you're going 65 mph...but I'm now going 70 mph pulling away and will continue to do so unless the "chasing" car has a steep enough acceleration curve to overcome the deficit.
So yeah...the majority of these roll races are largely useless unless done the right way...with vBox in both cars ran at same time side by side under exact same conditions to determine which one truly is faster.
S.
Thread Starter
Team Owner
Joined: Mar 2005
Posts: 20,933
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From: salem OR
Since you didn't read it to start with.
It is about the gearing differences to help some understand the differences between the two.
The low 10.99 vs .7.83 is like a 3.42 racing a 4.11. The 4.11 wins the 60ft the traction and the thus the 1/4 race.
The thread is about how the M7 matches up better in a roll contest.
Where it carries the advantage with a proper driver. The manual
is very driver dependant. One driver can clearly use skill than another and get more out of the same car.
The M7 has the roll race advantage with the closer gear spreads and less drive losses. Thus why a A8 dyno's about 25-40 less from what I've seen.
Thread Starter
Team Owner
Joined: Mar 2005
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From: salem OR
It's not the distance gained if one car gets a jump, it's where both cars end up on the acceleration curve.
A .3-.4 interval really isn't much at all. However, cars at this level will accelerate 4-5 mph in that interval. So if we run from 60 mph and I jump, in ~.3-.4 seconds I already have a 5 mph advantage before you even go WOT and am pulling. By the time you go WOT, ~.3-.4 seconds later you're going 65 mph...but I'm now going 70 mph pulling away and will continue to do so unless the "chasing" car has a steep enough acceleration curve to overcome the deficit.
So yeah...the majority of these roll races are largely useless unless done the right way...with vBox in both cars ran at same time side by side under exact same conditions to determine which one truly is faster.
S.
A .3-.4 interval really isn't much at all. However, cars at this level will accelerate 4-5 mph in that interval. So if we run from 60 mph and I jump, in ~.3-.4 seconds I already have a 5 mph advantage before you even go WOT and am pulling. By the time you go WOT, ~.3-.4 seconds later you're going 65 mph...but I'm now going 70 mph pulling away and will continue to do so unless the "chasing" car has a steep enough acceleration curve to overcome the deficit.
So yeah...the majority of these roll races are largely useless unless done the right way...with vBox in both cars ran at same time side by side under exact same conditions to determine which one truly is faster.
S.
You just restart again until it 's even. You pull an even roll race with both having traction you drive away end of story you have the faster car.
That's what I like!
Scraping the splitter.
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St. Jude Donor '13-'14-'15
Even a few tenths is more than people think.
S.
Melting Slicks
Joined: Oct 2006
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Unless I am misunderstanding something a 2:41 at VIR would be considered slow. My reference point is driving a SCCA T-1 Car in 2005 and turning 2:05 (for those who do not know, the T-1 was a C6 LS3 with stock motor). Best
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Scraping the splitter.
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St. Jude Donor '13-'14-'15
S.
Former Vendor
Joined: May 2014
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From: SAN FRANCISCO CALIFORNIA
Time doesn't start till you move even if someone takes off on first yellow 1/4 mile time won't be faster.
Scraping the splitter.
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St. Jude Donor '13-'14-'15
Thread Starter
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Joined: Mar 2005
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From: salem OR
So 99.9999999 percent of the time my car IS else where.
So I remember how much more enjoyment I get driving a manual.
Then I remember other auto purchases that were quickly sold because of no involvement other than a gas and brake. I like the control and the A8 guys are missing GM's best manual EVER the M7 with a MGW pure driving joy teamed with the best car.
Le Mans Master
Joined: May 2000
Posts: 8,729
Likes: 1,508
From: Redmond WA
Whatever helps you sleep at night. The difference between 3.2 and 3.0 is significant. It's not linear - it's not like the difference between 6.2 and 6.0
By that logic why paint the outside since you sit inside the car anyway 99.99% of the time?
Keep in mind also that most of us (I think, anyway) have had stick Corvettes in the past. I just spent 8 years with a C6Z06, it's not like I don't know what a manual trans is...
By that logic why paint the outside since you sit inside the car anyway 99.99% of the time?
Keep in mind also that most of us (I think, anyway) have had stick Corvettes in the past. I just spent 8 years with a C6Z06, it's not like I don't know what a manual trans is...
Thread Starter
Team Owner
Joined: Mar 2005
Posts: 20,933
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From: salem OR
Whatever helps you sleep at night. The difference between 3.2 and 3.0 is significant. It's not linear - it's not like the difference between 6.2 and 6.0
By that logic why paint the outside since you sit inside the car anyway 99.99% of the time?
Keep in mind also that most of us (I think, anyway) have had stick Corvettes in the past. I just spent 8 years with a C6Z06, it's not like I don't know what a manual trans is...
By that logic why paint the outside since you sit inside the car anyway 99.99% of the time?
Keep in mind also that most of us (I think, anyway) have had stick Corvettes in the past. I just spent 8 years with a C6Z06, it's not like I don't know what a manual trans is...
But the paint logic
is way off you could do better! Ready and waiting for roll races from the A8's!
Burning Brakes
Joined: May 2002
Posts: 1,010
Likes: 13
yep .2 of a second makes no difference except the drag strip.
So 99.9999999 percent of the time my car IS else where.
So I remember how much more enjoyment I get driving a manual.
Then I remember other auto purchases that were quickly sold because of no involvement other than a gas and brake. I like the control and the A8 guys are missing GM's best manual EVER the M7 with a MGW pure driving joy teamed with the best car.
So 99.9999999 percent of the time my car IS else where.
So I remember how much more enjoyment I get driving a manual.
Then I remember other auto purchases that were quickly sold because of no involvement other than a gas and brake. I like the control and the A8 guys are missing GM's best manual EVER the M7 with a MGW pure driving joy teamed with the best car.
Le Mans Master
Joined: May 2000
Posts: 8,729
Likes: 1,508
From: Redmond WA
Le Mans Master
Joined: Oct 2004
Posts: 6,813
Likes: 287
From: Toronto Ontario Canada
Thanks a GREAT point. There is no wrong choice.
People buy the color the options they want no wrong choice. But the A8 braggers
get old. They want to brag that the A8 is so fast when the M7 is faster in certain races. It sticks in their craw! They want people to think the A8
is faster in all races. It is not! That's my only point.
People buy the color the options they want no wrong choice. But the A8 braggers
get old. They want to brag that the A8 is so fast when the M7 is faster in certain races. It sticks in their craw! They want people to think the A8
is faster in all races. It is not! That's my only point.
Racer
Joined: Sep 2014
Posts: 475
Likes: 63
yep .2 of a second makes no difference except the drag strip.
So 99.9999999 percent of the time my car IS else where.
So I remember how much more enjoyment I get driving a manual.
Then I remember other auto purchases that were quickly sold because of no involvement other than a gas and brake. I like the control and the A8 guys are missing GM's best manual EVER the M7 with a MGW pure driving joy teamed with the best car.
So 99.9999999 percent of the time my car IS else where.
So I remember how much more enjoyment I get driving a manual.
Then I remember other auto purchases that were quickly sold because of no involvement other than a gas and brake. I like the control and the A8 guys are missing GM's best manual EVER the M7 with a MGW pure driving joy teamed with the best car.
Instructor
Joined: Jul 2015
Posts: 143
Likes: 0
In the big picture does it really matter if one car is a tenth or two faster? If I am spending 100k on a car I am going to buy the car with the trans that I want to drive even if it is slower and that is an M7, end of story. Comparing digs and roll races is also a great deal to do with the driver so even if specs say the A8 is quicker I am quite sure many "wheel men" can beat it all day driving a stick.
Last edited by mookiec; Aug 5, 2015 at 08:35 AM.