[JimGnitecki]

You can't fin d a Camaro brochure at a dealership these days, but GMmakes available a 2022 E-brochure, which I downloaded. Surprisingly, it contains the attached performance table which I took a screen shot of. I also myself created the attached MS Excel-based table comparing the gearing of the 10L80 automatic to that of the manual transmission. (Sorry that it is pdf format, not jpg, so you need to click on it below to open it)

Looking at each of these, you can quickly see that:

1. Regardless of Camaro model and packages, in EVERY case the automatic vehicles in the table have a shorter 0 to 60 and quarter mile time

and

2. The automatic vehicles also consistently have a higher trap speed.

Looking at my gearing ratio comparison table, I can quickly see why the 10-speed automatics are quicker than the 6-speed manual:

- The automatics have more gear ratios (10 vs 6) so the gap between ratios is MUCH smaller, and the smaller gaps keep the engine notably closer to peak power rpm. That means that for the full throttle acceleration runs, the average applied power to the rear wheels is going to be higher than on the manuals, and so the times will be shorter.

- The automatics can also execute each shift quicker, again cutting the elapsed time for any run (Both the automatic and the manual have the same number of shifts for the 0-60 and quarter mile runs - 1 shift to get to 60, and 3 to get to the end of the quarter mile.

- The internal ratios in the 10L80 automatic transmission are SO different from traditional automatic transmissions that DESPITE running either a 2.77 or 2.8X differential ratio, the cars STILL have radically "shorter" gearing than the manuals do (Just look at the table I prepared).

So, no surprise there.

But . . .

The increased trap speed IS a bit of a surprise.

Trap speed in the quarter mile has always been a fairly accurate measure of the actual rear wheel (not claimed crankshaft) power actually delivered to the rear wheels. The gearing on a car seemed to not affect trap speed noticeably. It only affected time needed for the car to get to that specific distance..

Manual transmission drivelines have traditionally sapped off about 12% of the power from the crankshaft by the time you get to the rear wheels. Traditional automatic transmissions have sapped off more like 22% of the crankshaft power.

So, traditionally, automatics have produced quarter mile times and speeds that were both worse than manuals. The 22% driveline loss lowered the actual power available at the rear wheels, in every gear, to accelerate the car.

The power loss on the traditional automatics was unavoidable. NO automatic could approach the 88% of crankshaft power transmitted tot he rear wheels that the manual transmissions could deliver.

But, here we find, per an official GM table in a GM brochure, that the automatic now delivers a HIGHER trap speed than the manual.

How is this possible?

IF our C6 Camaros had traditional transmissions, our crankshaft 455 hp would, on a properly calibrated and maintained Dynojet, properly corrected to the SAE (not STD) standard, show 400 rwhp for the manual transmission Camaros, and 355 rwhp for the automatic Camaros.

But, I don't think I have seen any dyno charts showing rwhp on automatic Camaro that was as low as 355.

Do the 10L80 automatics and 10L90 automatics have THAT much lower driveline losses?

Jim G

[Trochoidal]

The RPM drop between gears isn’t much on the automatics today compared to the older 350/400 turbos. These new automatics do run good.

Many equal powered/weight stick vs newer autos on YouTube show the stick car losing ground on each shift.

I used an online calculator sometime ago to express the shifts and you can see these RPM drops are higher than the reality of automatics being used today.

I never messed with the 10 speed since it’s not what I drive.

[arpad_m]

Originally Posted by Trochoidal

The RPM drop between gears isn’t much on the automatics today compared to the older 350/400 turbos. These new automatics do run good.

Many equal powered/weight stick vs newer autos on YouTube show the stick car losing ground on each shift.

I used an online calculator sometime ago to express the shifts and you can see these RPM drops are higher than the reality of automatics being used today.

I never messed with the 10 speed since it’s not what I drive.

The 4-5 shift on our A8s is similar in that it comes with a huge RPM drop and noticeably weaker acceleration afterwards (the gear ratio change is very large).

Driveline losses are still higher on an automatic car, many a dyno sheet has shown that the M6 has a small, but consistent hp advantage over the A8/A10.

[ZO6Ted]

I believe driveline losses for the 8 and 10 spds are only 14-16% compared to old school 4 spds around 20ish. but to your point the trap is confusing to me too on the manual vs auto.

[s346k]

the autos have a better gearing advantage, lock the converter early and shift faster. put a driver in the manual car and you'll have a good race.

[Chrome383Z]

The A10 transmissions are outstanding. Much better then an old M6.

[JimGnitecki]

I have not yet found any "pure stock" dyno charts, for manual and for automatic transmission C6 455 hp Camaros, that would enable accurately comparing the rwhp for automatics versus manuals.

I have done a forum search for "dyno chart" but got a zillion hits which I am investigating thread by thread, but there are a LOT of threads that mention "dyno chart".

Are there suitably clean dyno charts anywhere here on the forum? (Or elsewhere?)

Jim G

[wnta1ss]

Originally Posted by JimGnitecki

I have not yet found any "pure stock" dyno charts, for manual and for automatic transmission C6 455 hp Camaros, that would enable accurately comparing the rwhp for automatics versus manuals.

I have done a forum search for "dyno chart" but got a zillion hits which I am investigating thread by thread, but there are a LOT of threads that mention "dyno chart".

Are there suitably clean dyno charts anywhere here on the forum? (Or elsewhere?)

Plenty of dyno numbers have been posted, however trying to compare them to each other is apples to oranges. Dynos that read differently from each other, what correction factors were used, whether smoothing was turned off, whether it's wheel roller or bolted to axle, things are all over the place. On this forum I have seen stock SS reports ranging from 334 hp to 443 hp. Yes, that is a big variance.

Logic tells us that the automatic transmission will have a larger power loss than the manual transmission. You could look for tests on the exact same dyno of some manuals and some automatics, and average them out.

[JimGnitecki]

Sounds like finding truly comparable data could be a long and detailed process. :(

Jim G

[wnta1ss]

Originally Posted by JimGnitecki

Sounds like finding truly comparable data could be a long and detailed process. :(

Jim G

Yeah

Just one that I found, Jannetty tested an SS automatic with the base exhaust (2 tips not 4) and later a manual SS with NPP on his dyno some years back. The 2-tip automatic did 414 hp STP and the 4-tip manual did 429 hp STP. Just a single and inexact comparison, there is no change in advertised hp resulting from NPP on the Camaro, but it would be nice to compare configs as closely as possible.

[JimGnitecki]

Originally Posted by wnta1ss

Yeah

Just one that I found, Jannetty tested an SS automatic with the base exhaust (2 tips not 4) and later a manual SS with NPP on his dyno some years back. The 2-tip automatic did 414 hp STP and the 4-tip manual did 429 hp STP. Just a single and inexact comparison, there is no change in advertised hp resulting from NPP on the Camaro, but it would be nice to compare configs as closely as possible.

Thank-you for finding that comparison. I realize it is not perfect because of the exhaust system difference, but given that GM does not claim any power increase for the 4-tip exhaust, it's probably as close to perfect as we can find!

The other issue is that apparently "STP" correction is another way of saying "STD" correction, which usually reports hp numbers that are 2% to 4% higher than what "SAE" correction reports (because SAE correction assumes less favourable ambient temperature / pressure / humidity conditions than STD.

So, the most conservative estimate of the relative driveline losses of automatic versus manual transmission would use SAE versus STD numbers, since the factory uses SAE conditions when it says the crankshaft power is 455 hp.

Taking those 414 and 429 reported STD numbers, we see that:

The manual transmission results in 429/455 = 0.94 = 94% of the power getting to the rear wheels.

The automatic transmission results in 414/455 = 0.91 = 91% of the power getting to the rear wheels.

The implication so far is that the automatic loses only an additional 3% of the crankshaft power versus the manual.

But, we have 2 flaws here, plus a 3rd and 4th jarring reality check:

1. These are STD based versus SAE based, so the actual relative driveline efficiencies using SAE conditions (2 to 4% worse) are more like:

90% to 92% efficiency for the manual transmission driveline
87% to 89% efficiency for the automatic transmission driveline

2. The Jannetty testing was apparently done "years ago". But, in Googling when the 10-speed automatic was first used in the non-ZL1 Camaros, I see that it was apparently 2019. so, the question is: which automatic did the automatic-equipped Jennetty Camaro have? (i.e. was it a pre-2019 or a 2019 or later model year car). This is an important question because the 10-speed (10L80) was a brand new design developed by Ford for use by both Ford and GM, and probably had improved efficiency over the 8-speed given its entirely new architecture. So, are we seeing in this specific example a comparison of the manual transmission to the older 8-speed auto or the newest 10-speed auto?

3. A jarring reality check comes when you realize that older automatic transmissions lost a LOT more power than the power loss we are apparently seeing here. For example, the GM 4L60E 3-speed plus overdrive auto driveline used in the early 2000s model years automatic GM vehicles consistently delivered only 76 to 78% of the crankshaft power to the rear wheels.

4. Dyno runs are done in ONE gear, while 0 to 60 and quarter mile runs are done using multiple gears. Continue reading below to see why this is incredibly important.

Taking all of the above somewhat challengeable findings into account, I think I can draw some conclusions:

1. The availability of 8-speed and 10-speed automatic transmissions has been a real game changer because more ratios means less "gap" between ratios, which means that the engine rpm on full throttle acceleration does not drop as much after each gear change as it does on a manual. This means of course that the AVERAGE power delivered over the course of the acceleration run is going to be significantly higher for the automatic than it is for the manual. That of course means notably lower 0-60 and quarter mile times.

2. Because the average power delivered to the rear wheels during both the 0 to 60 portion of the run and the quarter mile portion, is higher for the automatic, the terminal velocity in the quarter mile will also be higher. Thus, the higher number of ratios in the automatic car actually make the automatic car "appear" (falsely) to have more peak crankshaft power than the manual, because we are all so used to regarding terminal speed in the quarter mile as a "reliable indicator" of a vehicles true horsepower. Thanks to these multi-ratio automatics, that "reliable" measure of power is no longer so reliable.

3. Dyno runs are done in ONE gear from beginning of the run at low rpm to the end of the run at high rpm, regardless of automatic or manual transmision, usually in the gear ratio that is 1:1 inside the transmission, or sometimes 1 gear lower in order to keep the dyno roller drum speed low enough to not overheat the rear tires. Therefor, the automatic car cannot "disguise" its inherent larger power losses by using its "more gears" feature on the dyno. The difference in torque and power for automatic versus manual at each engine rpm on the dyno is REAL. So, the automatic driveline, in the specific case we are examining, iS actually losing 3% more power than the manual driveline is losing. But, it IS apparently only a 3% power loss disadvantage.

4. A 3% worse driveline loss for the automatic is a rather small price to pay given the END RESULT of measurably BETTER acceleration because of the higher number of gear ratios available for acceleration. The OEM manufacturers, by moving from 3+1 ratio automatics to 7+3 automatics, have swept away the traditional acceleration performance disadvantage of an automatic.

5. But, a 3% power loss is still significant from a heat management perspective. 3% of 455 crankshaft horsepower is 13.7 hp. In physical terms, that is like having a 13.7 hp "heater" inside the transmission housing. Using the accepted conversion rate of 1 hp = 746 watts, this is like running a 10,200 watt heater in your transmission housing. No wonder we need a transmission cooler.

To make you feel better about that, remember that with the old 4L60E automatic transmission, the 22 to 24% driveline loss was like having a 78,000 watt heater in that transmission housing! No wonder my 5000 lb 2004 Magnuson Supercharged Chevrolet SSR retro hardtop convertible pickup truck fried even a Phoeneix-built 4L60E transmission within a matter of months in the Texas heat, necessitating an even stronger phoenix tranny!

Again, thank-you wnta1ss for finding that usable comparison data within the forest of data on the froum. It sparked all of the above.

Jim G