Why auto GTO faster than MT?

[majidz]

HI

I was talking with my friend about this point ..
usually the mt is faster than auto but in the new ls2 gto . the auto acc from 0 - 60 mile in 4.6 sec and the mt in 5 sec ... why ??? any problem with the mt gear box ?







majidz

[JiggaStyles09]

where did you see these times? to get a good answer you may want to provide the article where these times came from or where you are getting this info. :wink: i doubt this to be accurate.

[majidz]

read this from pontiac site :

Custom tailored and performance tuned, the 4-Speed Automatic provides performance that rivals that of the Tremec given a 0 to 60 time of 4.6 seconds. The secret: Software programmed to match the 4L65-E to the LS2's on-and-off throttle characteristics.

and if you see this article :

http://motortrend.com/roadtests/sedan/112_0502_trio/index7.html

you will see that the acc for mt gto is in 5 sec ..




majidz

[Refefer]

/\ It could be possible, if the at has aproximately the same gear ratio as the mt and isn't limited to 4 forward gears... a good at can shift cleaner than an mt, so maybe...

Heh, isn't really likely though... majidz, what's your source?

*edit* heh, you posted 1 minute before me...

[majidz]

refefer ..

see this in gto site :

http://www.pontiac.com/gto/transmissions_popup.jsp?imageNum=2&source=

this for auto trans ...

for the mt you can see motortrend site in :

http://motortrend.com/roadtests/sedan/112_0502_trio/index7.html




majidz

[JiggaStyles09]

ah i see. well, the most obvios answer is that the 2 times you were referring too were under different conditions, like different drivers, different road surfaces, different temperatures, possibly one for the cars had its proper "break in" time, there are a lot of factors that go into 0-60 times and 1/4 mile times. manufacturers claims and magazine articles tend to differ sometimes as well. my prediction is that if you were to test both of the cars back to back the MT will be slightly faster.

[majidz]

but do you thing that the gto with mt can goes under 4.6 sec ?? :shock:

may be you are right because i found some information about the new holden hsv with the same engin and gear box with new numbers ...

http://www.w6w.com/w6w.php?pic=466271

see this

[Refefer]

Hmm, now this is interesting.... http://www.gm.com/automotive/vehicle_shopping/quickfacts/pdf/05Pontiac_GTO.pdf

Straight from GM, it looks like the auto is faster then the manual, 4.6 at, 4.7 mt... what a shame.

However, that's only in a line, who knows how well it would do around a track

[majidz]

Refefer ...THANKS

i think i knew why the auto is faster .. because the first gear ratio is 3.06 but in the mt the first gear ratio is 2.97 ... the mt should be bigger than tha auto ..
and the final ratios in mt and auto are the same ... any one agree ??






majidz

[JiggaStyles09]

Refefer ...THANKS

i think i knew why the auto is faster .. because the first gear ratio is 3.06 but in the mt the first gear ratio is 2.97 ... the mt should be bigger than tha auto ..
and the final ratios in mt and auto are the same ... any one agree ??






majidz
thats quite possible, not sure though, maybe the MT GTO requires a shift before 60mph and the auto doesnt?? seems very odd that the automatic is faster though, i mean the reason that manuals are faster generally is that they get more power to the ground. automatics tend to have more loss through the drivetrain. can anyone else comment on this?

interesing find majidz :wink:

[gobs3z]

Well for drag racing auto's are always faster because of consistency, but in this case i think it has to do with it being a 4 speed. The 4 speed has gear ratios that are more oriented towards the torque of the car since is has larger and broader gearing while the six speed is close ratio and aimed more towards the horsepower of the car. I'll assume the manual has a better top end from the closer ratios and that the manual would eventually pull on the auto at higher speeds, but if you're looking at 1/4 times, the auto will always be faster. :wink:

[majidz]

JiggaStyles09.... thank ..
but i think that the mt and auto requires changing before 60 mi ...
i observed that the first ratios in holden auto cars are bigger than the mt .. and the mt in EPA rates much better than auto ..
but in the other sport cars like nissan z you will find that the mt ratios always bigger that auto ...
i think american cars should use better gearbox than these what they use ..





majidz