Manual or Auto?

[Speedster]

Thanks for the answers Steve. Like many other industries, the manumatic was tried years ago (like 50-60) but people like you have brought it into the 21st century with modern electronics (and brainpower).

Like many on this thread, I am exploring the present capabilities and plan on using the Shrifter/Auto setup on an upcoming project. How much weight does the Gear Vendors add ?

Thanks again Steevo !!

[Steve Chryssos]

Thanks

Where was I. Oh yeah. Weight for a 4L80E is 180 pounds. Not sure how much a T56 and clutch weigh. Gear ratios are 1:1 for 3rd and .67 for OD.

[Jr]

Steve,
How many up/down shifts do you count in the video you posted?

[Steve Chryssos]

Not very many. That wa strictly a second gear course. 4? 5?

[cutlasskid]

i have a tt set up and i can tell you the first 2 gears in the t-56 seam use less they go by so fast , my foot is off the gas more than on the gas untill 3rd comes along and then the car starts hauling i can say the 6th gear is great with a 3.90 rear gear on the highway 80mph and 2100 rpm you can't beat that. so if you want a good quater mile go auto.

[californiacuda]

Car and Driver has an article about the new Ferrari 599gtb. It has the same engine as an Enzo but with 40 fewer hp and weighs 700lbs more. Its 0-60 time 3.3 and 1/4 mile 11.2.

Same performance time as the Enzo. 700lbs more, 40 hp less? How?????

Answer. Paddle shifter and preset launch program(traction control). Technology works.

[Steve Chryssos]

Yup. And the latest Porsche Tiptronic Turbo is faster that the manual car. Automatics have always benefitted from better torque multiplication and no loss of rpm between shifts. But now, the power is getting through as well. That is mostly due to advancements in torque converter design. The Ferrari still uses a clutch, but the Turbo has a converter.

We developed torque converters in conjunction with Pro Torque that are specifically engineered for pro-touring cars. That means short tires and overdrive. Called MuscleDrive, our converters start with high efficiency turbines and impellors, custom built stators, high surface area, ceramic impregnated lock up clutches and race grade parts such as billet steel front covers, torrington bearings, anti-balloon plates and more.

The typical "street/strip" converter will yield slippage and power loss under part throttle application. Street/strip converters are spec'd for best WOT performance, but ignore the rest of the powerband. They're also cheap which means that they start with turbines and impellors from a 1980-something Oldsmobuick. Lock up versions have clutches that are typically no wider than a shoelace. OE style narrow clutches are only useful for light load highway cruising.

MuscleDrive converters achieve high coupling efficiency at a very low rpm. Stall speeds are calibrated for part throttle performance. The wide area ceramic impregnated lock up clutch can be applied over a wide rpm range. The lock-up clutch is strong enough to stay applied at WOT. And when you take your foot off the gas to dive into a turn, then engine and trans are directly coupled in lock up, so the converter tugs on the motor--just like a manual. I could throw you in the passenger seat, blind-fold you and tell you that you're driving in a car with a sequential manual.

Yeah....Technology is great.

[customcam]

With these new Coverters does it change the Hp Loss compared to prior Auto trans built?
Nearly every1 thats running a 'NA LSx Non drag only' car has a manual
I think it would be cool to have 6-8 speed Auto behind say an Na Ls2/7 600-650 hp
What would be the loss compare dto a Manual Steve?
thanks

[Steve Chryssos]

Yes. Absolutely. It is a question of coupling efficiency. If engine speed and transmission input shaft speed are the same, 100% coupling efficiency is said to be achieved. AKA direct drive. With a manual transmission, 100% coupling efficiency is achieved as soon as you take your foot off the clutch pedal. After that, the only loss is attributed to parasitic loss through the drivetrain. Ride that clutch and you get slippage.

For most of the automatic transmission's history, lock up converters did not exist. More importantly, converter design has been historically poor. A 1967, '77 or 1983 Oldsmobuick could barely muster 80% coupling efficiency. The engine spins faster than the transmission. The result is slippage. Like everything else, current software technology has made the difference in turbine and impellor design. (The turbine is connected to the input shaft and the impellor, aka pump is connected to the engine). Called Computational Fluid Dynamics, the software has allowed major auto maufacturers to achieve 90% plus coupling efficiency BEFORE lock up. It is not a major leap of faith. It is easy to accept that the converter from a 98 or 2002 vehicle is more efficient than one from an older car. Manufacturers spent ginormous sums of money to improve efficiency in the name of gas mileage. The aftermarket cannot afford this technology, so we start with OE turbine and impellor cores.

Your average street/strip bargain converter is still based on cheap-to-buy old fashioned (pre-CFD) cores. If your converter manufacturer starts with a slightly more expensive late model core, you take advantage of the much higher coupling efficiency rates. Higher coupling efficiency even makes it possible to run a lower stall speed. Power is getting through during the stall and acceleration phases, so it is less necessary to "slip" the engine up to a higher rpm where it makes more power. That high stall slippage feels horrible in a pro-touring car. Start with the right core and a lower stall, and it is possible to acheive a nice tight felling converter without hurting performance. And all this occurs BEFORE the final phase known as lock up where 100% coupling efficiency is achieved.

Once the converter is locked up, you achieve 100% coupling efficiency--just like a manual. The trick is to MAINTAIN 100% coupling efficiency by increasing the clutch surface area and using ceramic impregnated materials. Old school lock up converters have a clutch surface about as wide as your shoe lace. They only lock up under light load circumstances such as highway cruising.
But what if you make more power or want to use the lock up clutch over a wider range--say a winding road? With a heavy duty clutch, you can lock up the converter and leave it locked up without shear. I even use my lock up clutch to induce a small amount of engine braking--which is nice, since you never have excessive drag. These converters are especially useful for pro-touring cars where part throttle operation is key, where most street/strip converters are only spec'd for WOT performance.

Automatic transmissions get a bad rap for excessive parasitic loss when in fact, it is a question of parasitic loss PLUS slippage. While marginally greater parasitic loss is true, much of that parasitic loss is in fact the result of converter slippage. Start with high efficiency blades and augment them with a heavy duty clutch and the numbers are much closer. The difference can be hypothetically zeroed out by a converter's torque multiplication and the fact that there is no power interruption between shifts.

You won't be the guinea pig. I have three development cars at my shop, and I've already sold a few of these converters. There is no magic here. As with everything else pro-touring, we're just taking advantage of modern technology that has trickled down from the OE's. I work with Pro-Torque to make sure that you get a high efficiency, high quality part. They thought I was nuts, so I brought them a pro-touring car and showed them the importance part throttle "on the gas/off the gas" operation. When I send in an order for a Twist converter, they stop, put away their drag car "WOT" philosophy and engineer a converter for a pro-touring car.

I hope that all makes sense. If you need further clarification, be sure to give me a call.

[Steve Chryssos]

One more thing.. ..By geting all of the slop out of the converter, you get that nice "chugging" direct drive feel that makes a manual transmission so entertaining.