Auto vs Manual, which is faster in a all out race car.
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Joined: Feb 2003
Posts: 1,110
From: Naperville
Auto vs Manual, which is faster in a all out race car.
Me and my buddy were having a debate this evening over which could be faster a auto or a manual. He said auto however I said in most cases that's true however once you're speaking of a true all out race car the manual is faster, he strongly disagreed. I then asked him why pro stock cars use manual transmissions, he said they didn't and we bet a few bucks over it. So I went and got an old magazine to show him that indeed they used manuals, but he said since they were clutchless they were really autos. So I'm flustered here, are these "clutchless" transmissions that prostock and top fuel use really considered autos??? I thought that they actually used a slip type clutch. Also in an all out case how and why are the manuals faster??? I know they are more efficient and such however I want to email him your replys to finish disputing him and collect my bet money
. Thanks guys
. Thanks guys
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Joined: Jun 2002
Posts: 1,373
From: Metro Detroit, MI
The fastest cars (ie top fuelers) don't run either autos or manuals (or any transmission for that matter) so I guess you're both wrong .
Edit: Pro-stockers use clutchless MANUAL transmissions I believe. FWIW, 99% of guys running sub 10's use autos from what I've seen. Take it for what it's worth.
.Edit: Pro-stockers use clutchless MANUAL transmissions I believe. FWIW, 99% of guys running sub 10's use autos from what I've seen. Take it for what it's worth.
Last edited by ltlhomer; Oct 26, 2003 at 10:52 PM.
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From: 51°N 114°W, 3500' elevation
Depends on the type of manual transmission you're talking about. Top fuel and Funny car don't even use transmissions any more. They're direct drive with a special clutch that applys more pressure as the rpms increase.
Pro Stock use Lenco transmissions. They don't have to use a clutch or let off the throttle to shift so for them a manual transmission is faster. If the NHRA would allow them to use an automatic tranny I'm sure most would convert over to one.
When comparing a street car or a typical bracket car, an automatic is usually faster however since most of us are bracket racers and consistancy wins races, you'll see mostly automatic transmissions at the track.
A manual transmission including the clutch, flywheel, etc is lighter than an automatic so in equal cars a manual transmission car will be lighter and should be faster. A manual transmission also takes less hp to turn the gears compared to an automatic so more hp can reach the wheels to make it faster.
Because it takes time to shift a manual transmission (not everyone can powershaft nor is it recommended in a factory transmission) an automatic can usually run faster because it can shift faster. Even with the extra weight and more power loss through an automatic transmission, the automatic is usually faster.
If 2 cars were set up one with a manual and one with an automatic and each had the same amount of hp getting to the rear wheels the automatic would probably win.
Pro Stock use Lenco transmissions. They don't have to use a clutch or let off the throttle to shift so for them a manual transmission is faster. If the NHRA would allow them to use an automatic tranny I'm sure most would convert over to one.
When comparing a street car or a typical bracket car, an automatic is usually faster however since most of us are bracket racers and consistancy wins races, you'll see mostly automatic transmissions at the track.
A manual transmission including the clutch, flywheel, etc is lighter than an automatic so in equal cars a manual transmission car will be lighter and should be faster. A manual transmission also takes less hp to turn the gears compared to an automatic so more hp can reach the wheels to make it faster.
Because it takes time to shift a manual transmission (not everyone can powershaft nor is it recommended in a factory transmission) an automatic can usually run faster because it can shift faster. Even with the extra weight and more power loss through an automatic transmission, the automatic is usually faster.
If 2 cars were set up one with a manual and one with an automatic and each had the same amount of hp getting to the rear wheels the automatic would probably win.
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Joined: Aug 2002
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From: Teeter-tottering between Brilliance and Insanity
A stalled, or especially a braked automatic, is gonna eat up a manual off the line ever time, and with pretty equal cars races are almost always won from the line
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Joined: Feb 2000
Posts: 321
From: Syracuse, NY, USA
You will never see a pro car with a auto in it. Pro-Stock cars us a straight cut gear selector with a multiple disk clutch pack. They are able to adjust the clutch gaps to tune the launch to the track. A converter does not offer this adjustability. The trans they use (Lenco or otherwise) allows them to shift with out pressing the clutch in or getting off the gas.
Fuel cars use a direct drive unit with a clutch. This means the trans has only reverse and a single 1 to 1 forward gear. They also use a multi-disk clutch pack that uses timers to gradually apply clutch while going down the track. In a fuel car the clutch is slipping most of the run and will lock up usually around the 1000' mark.
You will find that 99.9% of bracket cars and sportman cars have autos in them. The reason for that is they are less expensive and are easier to make consistant. But the bottom line is a properly set up pro-shifted manual will be quicker than an auto.
If you need examples just look at the NHRA comp eliminator index's. Look at classes such a AA/A and AA/AM where the only difference is a auto or Manual trans. The Manual trans cars will always be quicker.
Fuel cars use a direct drive unit with a clutch. This means the trans has only reverse and a single 1 to 1 forward gear. They also use a multi-disk clutch pack that uses timers to gradually apply clutch while going down the track. In a fuel car the clutch is slipping most of the run and will lock up usually around the 1000' mark.
You will find that 99.9% of bracket cars and sportman cars have autos in them. The reason for that is they are less expensive and are easier to make consistant. But the bottom line is a properly set up pro-shifted manual will be quicker than an auto.
If you need examples just look at the NHRA comp eliminator index's. Look at classes such a AA/A and AA/AM where the only difference is a auto or Manual trans. The Manual trans cars will always be quicker.
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Joined: Feb 2002
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From: Huntington, WV USA
Wow, you mean this thread, the subject of which comes up often, so far really contains useful info with no bickering or auto vs. manual challenges? How could that happen. Things never cease to amaze me!!! 
Last edited by quick91rs; Oct 27, 2003 at 09:15 PM.
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From: Louisiana, USA
All things being equal and a real good driver a manual will be faster than an auto and quicker too. But run them 2 out of 3 and that auto may get him. Manuals are also brutal on parts when 5500rpm and above clutch dumps are used to get good 60's so rearends, outputshafts, driveshafts and axles are all at risk almost every pass. Also clutchs don't last very long either with that kind of abuse so theres some more reasons us drag racers prefer autos.
Manuals are also brutal on parts when 5500rpm and above clutch dumps are used to get good 60's so rearends, outputshafts, driveshafts and axles are all at risk almost every pass. Also clutchs don't last very long either with that kind of abuse so theres some more reasons us drag racers prefer autos.
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From: Buffalo, New York
Fastest of all is an electronically shifted manual as in Formula One, which is not used in drag racing. But barring that as an option, it depends on the car, especially the power to weight ratio and the powerband. For a street car based drag racer, the fastest of the readily available options would be a clutchless manual like a Lenco or a G-Force. But if you mean a T56 vs. a stock auto, it's a tossup. I'd go with a speed shifted T56, but I don't think one would stand up to that for very long. However, the T56 would be harder to drive to maximum potential.
Rich Krause
Rich Krause
