C7/Z06 Man

On The Drag Strip:

Reaction Time= has nothing to do with your ET/MPH. It's the time it takes you to break the starting line beam after the light goes green. However when 'Bracket Racing' reaction time 'usually' decides the winner/loser of a race.

ET= breaking the starting line beam and then the one at the finish line.

MPH= is determine by breaking a beam located before the finish line and then the finish line beam.

Note: From what I have seen at the track it's usually more than a couple tens separating the manual from the auto. Having said that I would like to pilot a stock stick against a stock auto. I bracket raced a stick for years and when I switched to a built auto w/high stall converter being the 'only' change I slowed down 2 tenths in the 1/4 with the auto and lost nothing in the 60'. I agree drivers can make a difference.

Edit: Someone 'originally' said something about not being able to feel .1 or .2 (tenths) 0 to 60 mph in these cars, 'not' the 1/4 mile. Well with these cars 0 to 60 and the first 60' is not that much of a difference in distance going down the track especially when your talking 1.5's, So let me ask you 'bracket racers' can you feel (BIG TIME!) the difference between a 1.5 60' and a 1.3 60'.

BooSSted

Lol..
Punky ... I suggested you need to go some where many replies ago. Now you have MORE people with actual seat time racing cars, schooling you. Yet you stay persistent with your baby brain comments.

Go lick your wounds and reply to the: "what wax and best intake" threads. That's more your speed.

383vett

I'll take a shot at this one C7/Z06Man. My bracket car 60's 1.35. My Z06's best has been 1.59. When your front tires leave the ground and you see sky for a couple of seconds, it's pretty cool. A few posts ago, Punky mentioned the feeling of speed is feeling the mph going through the traps. For me, that is not true, the car (at least a 10 second car) is not accelerating very quickly through the traps and the driver is just around for the ride. The thrill and the feeling of acceleration for me is at the start, or at least through the first couple of gears.

djnice

Thanks for clarifying this. I wasn't sure what it was doing because sometimes it seemed to skip gears and other times not.

On a separate subject. You sort of have to use M mode on road course and mountain driving. If you don't it doesn't shift right. It upshifts too much and then has to down shift 3 gears at the apex. You can't hit full throttle and make it skip gears or you will get too much chassis imbalance. The inconsistency is really a problem for performance sport car driving. Once you switch to M mode it takes away some of the advantage. At this point the biggest benefit is you can concentrate on brake, throttle, and stearing and avoid dealing with clutch and shifter. This is a big plus. Both trans options have compromises.

DevilDog II

Wow! 11 pages of comments and I'm still not sure which is the best transmission. Maybe we should just say that the transmission you chose is the best for your personal driving habits/needs and leave it at that.

b4i4getit

The best transmission is the one you have.

punky

I hope "BooSSted" and the other A8 fist pounders here don't read that one. They are Faster, Faster, Faster, and can easily "feel" the difference. LOL.

davepl

You don't need to "feel" it, just look at the car in front. In a zero to sixty rip, it's a big difference. You'd be somewhere around 80 feet per second, so 1/4 of that, or 20 feet.

20 feet's a "win" in A8 land, I don't know what they call it in roll race town.

This is way wrong, at least it's very contrary to my experience. Maybe you drove an A6? The A8 is magical about picking the right gear on the roadcourse. Now I've only driven 3 different tracks in the A8, but 2 of those were tracks I used to run in my M6, and it felt "right" to me.

The only problem, of course, is it holds lower gears (contrary to what you said) and tends to overheat the car. But that's the cooling system's problem, not the trans.

punky

The internet racing champions in this thread are certainly adamant about their ability to "feel" a big difference between the two.

djnice

The A8, but it was in a GS. Yes, it would hold lower gears when accelerating and rev to redline, but it was not consistent about holding gears when braking into corners. I tried different modes too. I would get to the apex, roll into the throttle, and have to wait for it to shift down 3 gears. I am sure these issues can be tuned out, worked around, or just use manual mode. I am not complaining, I like the A8, I am just sharing facts about what I found.

BooSSted

No one aside from yourself has said anything about feeling a difference. Everyone is telling you the .XX difference will result in getting gapped.

davepl

How new was the car to that environment? I found mine took a while on the street to "learn" me (or me, it) and then again ont he track, but it sorted out after a few laps.

That or maybe I just got used to what it was doing, I couldn't really tell you for sure. But I know it is supposed to "learn" and improve, whatever that means in reality...

z06vettewannabe

Totally personal preference, but I'll never get an Auto (unless of course they eventually stop making manuals). I just love rowing my own gears. Fully acknowledge the performance advantages of Auto, but don't care. Too much fun driving a manual for me. Good luck with your choice, ultimately the "BEST" transmission is the one the suits you best.

djnice

The car had a lot of high speed highway driving and a lot of manual mode. However, it should have learned over a 1 hour mountain full of corner after corner. I wish I still had it to test some things, but hey I get to drive one at Spring Mountain this fall.

Warp Factor

I haven't experienced that, but we don't have that many windey roads in Michigan, so I haven't had a chance to sort it all out. For the most part, when I was driving aggressively, and the G-loads were high, the transmission in auto mode seemed to pre-select the lowest gear which wouldn't over-rev the engine. Didn't need me mashing the throttle, or using the paddles, before making the decision to down-shift

"NSC5" seems to know a lot about these transmissions, so maybe he can comment on whether G-loads are a factor in gear selection in "auto" mode.

NSC5

Tadge addresses this to some extent in this Ask Tadge thread where he notes that to avoid upsetting the chassis some auto downshifts are prohibited above a certain lateral acceleration level (i.e. G force). An abrupt multiple gear downshift would definitely upset a chassis on the edge of the friction bubble whether for acceleration or engine braking:

See the thread here: https://www.corvetteforum.com/forums...in-detail.html

Jsilvester81

Quote:
Originally Posted by dar02081961
Dave here is a piece I wrote about 2 years ago when this discussion came up. I have since studied it further and broken down the percentages of time each transmission is at an advantage for the 50 mph to 170 mph run. Not included here. Anyway, it shows that where the race starts (0-170 mph) will determine which transmission will be at the advantage. Like anything else in life nobody wins all of the time.

Tha
"The A8 has advantages in certain areas of the acceleration curve. It also has the advantage of shifting a bit quicker.

However the A8 has the disadvantage of having a higher percentage of drive train loss.

The A8 is quicker in the 1/4 due to the gearing advantage in first which gets it off the line.

If you look at the gearing you will find the A8's only clear advantage is from a standstill. Or said another way there are periods during the acceleration curve where the A8 has less torque multiplication than a M7. For example when the A8 shifts to 2nd at 45mph (redline) the M7 is still in first. From 45 mph until about 68 mph the M7 has the gearing advantage. AND this advantage is greater because of less drive train loss for the M7.

Also the A8 makes 3 shifts from 0-125 mph while the M7 only needs 2. Yes the A8 shifts quicker but it shifts more often which takes time.
So from a roll in the real world (at the speeds a roll on is likely to happen) the A8 advantage may not be what many folk think it is. And above 125mph the M7 holds the advantage until about 150mph.
Then its A8 and back and forth until max speed.

From a 50 mph roll on the A8 would have the theoretical advantage because the M7 can’t go back to first. I say theoretical because it’s hard to quantify the momentum the M7 would gain from a no lift down shift to 2nd vs the A8 automatic down shift to 2nd. (Ok I could do it but my head already hurts)

Regardless the A8's advantage is short lived because the A8 shifts to 3rd at 71 mph while the M7 can hold second until 95 mph.

So the A8 pulls off from 50 until it shifts at 71 mph, where it losses time (however long it takes to shift), then it losses hp (gearing, 3rd vs 2nd) and it constantly losses hp due to drive train loss. So the M7 should close some if not all of the gap.

At 95 mph when the M7 shifts to 3rd the advantage may go back to the A8 until 102 mph (due to time for the M7 to shift and gearing). But there may not be time for it to show much because of power train loss and the short (7 mph) time span the advantage is applied.

At 102 mph the A8 losses time from the 3-4 shift. From 102 mph all the way to 126 mph the M7 has 2 advantages. Gearing, and less drive train loss. If there is any gap at this point the M7 will close it and likely begin to pull.

At 126 mph when they both shift, the A8 will my close for a split second due to the quicker shift vs the M7. However after the shift is completed the M7 continues the hp advantage it has held (gearing AND drivetrain loss) since 102 mph all the way to 155 mph when it shifts into an acceleration killing 5th. The A8 will arrest the pull and begin closing the gap until its forced to shift at 170 mph. Its doubtful the A8 will make up all of the gap the M7 has been creating since 102ish mph in the next 15 mph. I suppose it could but some of its gearing advantage from 155-170 is negated by drive train loss.
So as you can see after we get rolling, the A8 advantage aint always what it’s cracked up to be."

Warp Factor

That quote has already been posted, and commented on in this thread. Did you have something to add?

Jsilvester81

Daves research sounds legit.

if faster is standing 1/4 A8 is faster
if faster is 100 - 186 M7 is faster

although the A8 shifts faster it is geared to be a 1/4 rock star.

M7 is geared to be a high speed pull rockstar

it is not accurate to make a blanket statement that the A8 is faster.

too vague.

At Wot there are points of A8 being faster
and there are points of M7 being faster

davepl

That research, to be clear, is from DAR, not me (Dave) unless he's named Dave too.

But back to the topic, you could impress me with a scenario where I go

"Yep, the M7 is faster in that scenario, and I care about that"

...because if it's some weird thing like "From 71mph through 93mph the M7 holds the advantage" as documented above, that's not very compelling from a performance standpoint.

All I know, and mostly what I care, is zero to sixty and quarter mile. But sometimes mags publish roll starts from 5mph or "passing" from 40-60, for example. If you can find those where the M7 wins, that'd be interesting.