Automatic vs Manual

[Mixedpuppy]

People tell me a lot of different things.

Most people tell me that manual performs better than Automatic in the 1/4 mile. Some people say that Automatic is better especially if you don't really drive manual very well. Three questions for everyone.

#1 How much of a significant difference can stock manual late model F bodys perform vs auto F bodys in the 1/4 mile?

#2 How much of a difference when you start adding aftermarket parts 1/4 mile? Can they easily balance out?

#3 How difficult and expensive is it to convert an automatic late model F-Body to Manual? Would it be better to trade it in for a manual to place aftermarket parts?

Appreciate the wisdom fellas.

Mixedpuppy

[davis80]

I can answer your first question, but you'll have to let the other experts answer the other two.

An A4 in the quarter mile will yield more consistent ET's and I believe slightly lower ET's because you can load the wheels before launch, but with the M6 you will trap at a higher speed.

[Jeff_in_Atl]

Deep subject.

#1 If you can stick it, the stick is usually a little faster because of several things one of which the gear ratios are a little closer together so you can stay in your horsepower band better. The torque converter isn't 1 to 1 in transferring it's power either. There is a little loss there. The automatic usually is more consistent with it's times.

#2 I don't know that this makes much difference here. I can't think of anything to type.

#3 check out this. http://store.yahoo.com/speedautomoti...o19t56chk.html Note this does not address the computer issue. I think you'll have to either get a 6spd computer or reprogram yours to at least change the speedometer pulses to recalibrate it. I have given this some thought too and I am not sure which is better to convert or to trade. I hate buying and selling cars.

#4 not listed. LOL The stick will get better gas mileage. I have been amazed at hearing guys getting 30+ mpg and even a 34mpg. We're talking Honda civic range here out of a 300 hp V8. I get around 17mpg in town and 28 on the road with my A4 and 2.73 gears. I hate paying for gas. More accurately, I hate where that money goes but that is another subject.

[Mixedpuppy]

I know the stock torque converter is supposed to be larger than the manual, but I have been teased in the past by a few people that I bought my '98 TA as an Automatic. I really like my car, it is mostly stock with a few minor mods on it. I just hate the thought of if I wanted to take my car to the track and basically get smoked everytime and thnking to myself, I should have gotten a manual.

[Christopherrr]

hey I have an A4 on my TA...haven't run it the 1/4, but my GTA, A4 also, can do 14.7 @ 94+ don't have my slips, but it's somewhere around that...had a guy come up to me and say "I had one of those, it's auto, did you know they are faster than a stick?" I was like "uh...okay, I didn't know that"...

[Joe 1320]

It all depends on the driver....... If you aren't really swift with a manual, an automatic can smoke you all things being equal. My bolt on LT1 auto is about the same as a comparible stick car. I have done as much as possible to lessen the parasitic drag of driveline parts and increase HP as well. The mods work the same on stick and manual. Even a Hypertech power tuner can make up the difference behind a stick car by firming up the shifts and changing shift points. That is a point often left out of the discussion when others claim no gain when using a HPP+..... alot of the gain can only be seen by automatics.

[Injuneer]

Depends on the driver.... I thought I knew how to drive a manual, but my performance with 500HP under the hood was pathetic. Switching to the TH400 dropped me from the low 12's well into the 11's. I don't think I would have been able to handle the 125-shot on top of that with a manual.

Still only running 11.1@128, because the convertor is sized for a 300-shot, and it doesn't flash very high without the juice. But, a buddy of mine with a 125-shot on an LS1 and a 6-speed was pulling 10.8@126MPH..... best dang manual shifting I have ever seen. But even he has switched to the TH400 for this season because of the need for consistancy and the heavy abuse a clutch takes with 6K dumps. His initial runs with the TH400 showed his ET's were the same, but he lost about 2MPH.

[StangEatr]

i thought, but may be wrong, that auto gets to a high speed faster, but manual has a higher top speed.

[Injuneer]

The torque convertor multiplies torque. A high stall allows you to launch near your torque peak. That gives you a huge edge off the line. Once you get going, the torque advantage of the automatic disappears, and the "slip" in the torque convertor starts to cost you power and MPH..... so you are correct, auto gets you going faster, but a manual should produce better MPH in the traps.

The drivetrain losses with a big stall, non-locking convertor are huge.... with my setup, at 783flywheel HP (on the engine dyno), the chassis dyno results showed:

12.1% drivetrain loss with the T56 (689rwHP)

21.3% drivetrain loss with the TH400 (617rwHP)

But the NA (<500HP) MPH was the same with the TH400 as with the T56, and the ET was at least .5-sec quicker. But that was just my inept shifting.

I still haven't made a pass with the full 300-shot, but we have run it on the dyno, and it should be one he!! of a ride. With the nitrous kicking in as soon as the throttle moves, it should flash the convertor to 5,000rpm off the line and put me at the peak flywheel torque value 800ft-lb. Put that through a high multiplication TC, and 4.10 gears and it should pull pretty good. If I can just get my exhaust finished, and make one last check on the dyno, it will be ready to launch... hopefully in about a month.

From what I have heard, its easy to make a case for a manual to about 11 to12-seconds, the auto becomes very attractive down to about 9.0, and then you can't afford the huge drivetrain losses and have to go back to a manual. But by then you can run a programmed clutch engagement, and a smooth shifting/clutchless Liberty or Lenco gearbox for consistancy.

[Joe 1320]

In the Turbo Buick camp, there have been many experiments. The overall winner is a 4 speed automatic. There are numerous examples of 9s using a BRF TH200R4. Incidently, locking the converter early at WOT is good of a .2 reduction in ET and 2 mph over non locked, backing up the effeciency loss that Fred stated. I have verified this with my GN that just gets into the 10s. Locking the converer does ultimately take it's toll on the parts unless a custom bulletproof high dollar converter is used. It does show the desirability of the automatic for launch and initial acceleration, but the need for a direct lockup on a top end charge. There is one point that hasn't been covered. If you plan on any extended top speed running, like perhaps the Silver State Classic, an auto trans won't live very long. They don't like extended high speed and rpm very much. The stick shift is the only good choice for that. Top speed is merely a function of HP overcoming aerodynamic drag and gearing, the air doesn't care whether it's a stick or auto. the're both about the same. Gas mileage in the stick is better due to the double overdrive gear though.

[Jay 02 TA ws6]

All of this debate leaves out the most important thing...

FUN!

Rowing through the gears, dumping the clutch, and generally beating the hell out of it is fun!!! There is no feeling quite like nailing that 2-3 upshift perfectly and hearing the tires break loose at 75 mph.

Sure the gas mileage and the top speed is nice. And yes, in stock trim a manual produces lower ET's and higher trap speeds. (13.5 @ 106 for a friend of mine with a 2002 with 4 speed) But the most important thing about these cars is how much fun you can have with them, and IMHO the manual 6-speed multiplies that fun exponentially!