what are the pros and cons of automatic and manual transmissions?
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Well I cant say much for the turbo cars but from my experience on a nt, the auto breaks usually atleast once a year lol, I had mune rebuilt twice and the first time then went throught five gear boxes if that tells ya anything. Since I swapped the tranny to a manual I havent had a problem, as for racing Im hardcore that you can race an auto and with proper mods keep up but go with the manual, my opinion, the belts in a auto wont stand the strain from shifting that quick for long, and besides with a manual you can control when you shift instead of a computer, hoping that the computer will shift at the right time and never mess up. My opinion though
Auto would be the way for drag racing, but obviously if your car is built you auto tranny will have to be built as well. Standard will be more fun to drive and give you better control of the car if you were to do something besides go in a straight line. Auto's are good if you want you mom, grandma, gf to drive lol. I'd say manuals are given more respect regardless of what type of racing it is. I don't think auto's are really good for anything besides a straight line. Gl with finding a dsm.
Pros:
Brake boosting
Preloads drivetrain (less snapped axles)
Faster shifts
Never misses a shift
Cons:
Absorbs some power (10-15% is a common figure)
Rebuilds are a pain
To add to this list (some of these don't apply to drag racing):
Pros:
-Boost between shifts
-Consistent
-Typically much stronger than M/T counterparts
-Around town driving
-Your mom or wife or grandma can move your car
-As easy to rebuild as M/T
Cons:
-Not as fun to drive at times (slamming through the gears can be rewarding)
-Heavy sumbeaches
-Launching takes more practice and patience
-Not good for Auto-x/Road Course without some sort of shift control
As long as your not repeatedly launching overheating shouldnt be too much of an issue. Nice coolers are available at reasonable prices too. The auto is a power absorber, but you will gain alot of consistancy. They arent as fragile as the 5 speed trannys either. Its really just personal preferance.
I'd say go with the 5 speed. Automatic transmissions take a lot of the fun out of drag racing and as far as I've looked more expensive to upgrade then a manual trans.
To add to this list (some of these don't apply to drag racing):
Pros:
-Boost between shifts
-Consistent
-Typically much stronger than M/T counterparts
-Around town driving
-Your mom or wife or grandma can move your car
-As easy to rebuild as M/T
Cons:
-Not as fun to drive at times (slamming through the gears can be rewarding)
-Heavy sumbeaches
-Launching takes more practice and patience
-Not good for Auto-x/Road Course without some sort of shift control
If drag racing is going to be your fix for going fast. An auto trans is the trans for you. All the above mentioned pros will certainly make it worth it's weight in gold..no pun intended. If you plan on making serious awd horse power you'll be much much better off with the AT. For as long as I can remember 7-10 second cars have been using auto transmissions to eliminate the mistakes, inconsistencies, and in our cases is a great way to cut down on drive train demolition.
I agree 100% that A/T takes somewhat of the fun out of driving but as long as your still turbo and AWD for that matter then its still quite a bit of fun to drive.
I would stay auto! I have owned 3 1g DSM's and all the manual versions were always down for repairs. I've gone through 5 transmissions in the manual cars. I now own an auto DSM and love it! If you are wanting to make an auto fun to drive, try using a shift box. You control each shift just like a manual but you don't have to let off the gas meaning you stay in full boost all the way down the track. As for reliability.... I drive the crap out of my car and have only destroyed one auto tranny because a bolt in the strut was the wrong size which let the hub move on a launch and the axle broke punching a huge hole in the case of the tranny. That sucked! All in all, it is your choice on what you want to drive
I had my car at the track last weekend for the local 1/8th mile street legal drags. I out launched every car there because of the combination of brake-boosting and AWD. Sadly, the T25 (R.I.P.) didn't have any top end and most people caught up. It finally died that day.
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Wes - '97 Talon Tsi AWD
While its true that an auto drive train loses some 10% to 15% power to the wheels at WOT that’s only important near or past peak horsepower RPM. While the converter is slipping the engine is at a higher RPM than for a manual car and is making more power. With my high stall TC the engine goes immediately to 4000 RPM at WOT and I don’t mind the lower efficiency.
One more thing: A manual may be more fun for canyon carving while it has your full attention, but the fuzzy logic on the auto is always paying attention and trying to keep the right gear selected. This can keep you alive if you’re past your teens and no longer immortal.
In 1997 when the TSI was brand new I was driving my new baby in the right lane of a four lane divided when a pickup came through a red, across his merging lane, and tried suicide by Talon. ABS was not enough but an emergency lane change onto the empty merging lane worked. When I released the ABS the Talon had made a two gear down shift and was in second gear with RPMs up, boost up and ready to go. While passing the pickup at WOT and 7000 RPM the transmission took third with a bang. By the end of the merging lane I was clear of the pickup, back on the highway and lifted the throttle. The Talon held third gear for a long time seeming to ask if I really wanted to use overdrive, or wouldn’t I prefer to go back down on the throttle.
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Maurice G.
98 TSI Stroked and Stalled
If you save the pic, the missing lines will apear. Stupid photobucket.
I made this 1G Auto vs VR4 Man overlayed graph to compare revs vs mph
for yous dudes up there using mph kph down here in Australia
A VR4 has a 2.846 1st & your 1g/2g man has a 3.083 1st, so the pink man
1st gear is a bit more generous in a VR4 man overlay.
If you draw horizontal lines over this graph, you will see your revs per
gear change. eg: Auto 1st @ 7k gives you 4k changing to 2nd. etc etc.
Notice the Auto 2nd gear legs. Don't give an auto a rolling start drag ;]
Cheers !
____________________________
--Aldo
LSD Auto & LSD rear. Switchable FWD/AWD
Last edited by AWD_Hybrid; 06-21-2009 at 09:18 AM.
Reason: edit
Aldo,
That graph shows a linear relationship between RPM and speed. For an auto with a slipping torque converter that is not true. As noted in post 15 above my Talon may be at 4000RPM at 15 MPH in first gear and when the wheels catch up at the 7000RPM shift point the car is only doing about 40 MPH. The torque converter is like having more gears. The high stall TC comes off the line as if the Talon is running a jeep granny gear.
____________________________
Maurice G.
98 TSI Stroked and Stalled
Hi matey. Yeah I understand what you are saying about your high stall
convertor making the graph incorrect bellow your 4k. So long as you
are still using the same large dia convertor, it will be efficient from 5k
onwards. That's why your 40mph at 7k in 1st matches the graph. The
smaller dia high stalls are more inefficient up top. I use a 3.2k stall
so I still have decent engine braking. If you are right into autos & are
interested in using a switchable transfer on your auto, well as you know
you need the centre diff welded for starters. You use the auto front tc
section. You get 4.5mm (around 7/32") machined off the back of the
front auto section. (I ground the top level on the man switchable mid
section) Mark the new straight intersection & only remove the 7/32"
from that line downwards. This makes it a snug joint like dowling.
Now the 2 gears will mesh properly. I didn't need the shim. But check
your shaft turning tollerance. If tight, use your std shim.
If you are going on a long cruise, switch it to fwd. Saves mega gas.
Cheers !
PS: The manual section needs the top bracket ground back a bit.
No bolt to line that up with on the auto box.
____________________________
--Aldo
LSD Auto & LSD rear. Switchable FWD/AWD
Last edited by AWD_Hybrid; 06-21-2009 at 11:01 AM.
Reason: edit
Exactly,everyone is saying autotrans for drag..Will someone delete that rebuilding is a pain on Knochgoon's post..I have only rebuilt one auto and one manual tranny in my life, and I must say that with the proper tools, the auto was MUCH easier to rebuild..There are alot of upgrades out there for auto trans as well..Man valve bodies, shift kits, better shift solonoids, tranny coolers,..EagleTalonTim sell those wonderful auto shift boxes, if you feel the need to shift.. point is there are tons of stuff for performance in an auto tranny..
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92 6/4 Auto EVO 3 16G
My Turbo Is My Radio
Exactly,everyone is saying autotrans for drag..Will someone delete that rebuilding is a pain on Knochgoon's post..I have only rebuilt one auto and one manual tranny in my life, and I must say that with the proper tools, the auto was MUCH easier to rebuild..There are alot of upgrades out there for auto trans as well..Man valve bodies, shift kits, better shift solonoids, tranny coolers,..EagleTalonTim sell those wonderful auto shift boxes, if you feel the need to shift.. point is there are tons of stuff for performance in an auto tranny..
I deleted it. I was going off the word of a friend. Oops.
I've yet to see the manual valve bodies for our cars. The shift kits are nice, and tranny coolers are a must.
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Wes - '97 Talon Tsi AWD
I'd say go with the 5 speed. Automatic transmissions take a lot of the fun out of drag racing and as far as I've looked more expensive to upgrade then a manual trans.
they are not more expensive at all!
to upgrade an auto to hold more power you will need the following
-end clutch kit $89
-shift kit $92
-trans cooler ~$90
-restalled converter ~$400
-labour for the internal work ~$300
-synthetic fluid ~$100
so for about a grand you get a trans thats very capable of holding 500hp. compare that to a manual.
-clutch
-flywheel
-TOB
-etc....
I don't know the exact prices for these things but they add up quickly to be more than the auto.
____________________________
92 Talon TSi AWD
Automatic
to upgrade an auto to hold more power you will need the following
-end clutch kit $89
-shift kit $92
-trans cooler ~$90
-restalled converter ~$400
-labour for the internal work ~$300
-synthetic fluid ~$100
so for about a grand you get a trans thats very capable of holding 500hp. compare that to a manual.
-clutch
-flywheel
-TOB
-etc....
I don't know the exact prices for these things but they add up quickly to be more than the auto.
I have a manual that was built be tre but im considering swaping over to an auto once my 5 speed goes out or if i decide to drag the car more often. Also you cant beat how reliable and consistent autos can be.
Ive seen some auto trannys with the "blue wire mod" and fresh fluid running real fast times. This goes to show how underrated these trannys are!
I have a built Auto trans from IPT with 3300 stall. A year ago i was running that setup on a 16g on 18 psi. It was really cool practically having the 16g fully spooled on the line before launch. I can honestly say out launching 5 speed subaru's and some evo's was pretty fun.
The power potential and consistency is great with a great spool up off the line. Im going with a new setup this year with a Gt35r. Im really curious how that will spool up, i might need Anti-lag and nitrous.
5 speed s are fun but i would take the Auto for a big race, at least i wont be sad that i missed a gear
auto tranny pros and cons
kph down here in Australia 
Oops.
