Automatic shifting?
Registered User
Joined: Jan 2003
Posts: 602
From: San Jose, Ca
Re: Re: Re: Re: Automatic shifting?
Originally posted by treyZ28
Are u sure? I'm almost 100% confident you are wrong unless there is some differance in Lt1/LS1 which i doubt.
At the track, the car in front of me broke down and i was still in 2nd frommy burn out. 10 min later i roll upto the line forgetting i'm in 2nd.
Launch and around the 1/8th i kicked this **** out of the rev limiter.
I KNOW i didn't start in 2nd because i was RIGHT next to a 12 second camaro till i hit the rev limiter. I also pulled a 1.9 or 2.0 60 60ft which isn't happening in 2nd gear start. My mph also looked ok
Why would they put an "2nd gear start" button in the firebirds if this was true?
Are u sure? I'm almost 100% confident you are wrong unless there is some differance in Lt1/LS1 which i doubt.
At the track, the car in front of me broke down and i was still in 2nd frommy burn out. 10 min later i roll upto the line forgetting i'm in 2nd.
Launch and around the 1/8th i kicked this **** out of the rev limiter.
I KNOW i didn't start in 2nd because i was RIGHT next to a 12 second camaro till i hit the rev limiter. I also pulled a 1.9 or 2.0 60 60ft which isn't happening in 2nd gear start. My mph also looked ok
Why would they put an "2nd gear start" button in the firebirds if this was true?
Registered User
Joined: Dec 1999
Posts: 2,779
From: Denton, TX
Re: Re: Re: Re: Re: Automatic shifting?
Originally posted by Aklaim
It is different between LT1 and LS1 cars.
It is different between LT1 and LS1 cars.
Like I said, I was pretty sure in my old LT1 when in 2 it started from 1st gear and shifted only to 2nd.
Trey: Go and take ride in an LS1 and see it yourself.
Banned
Joined: Aug 2001
Posts: 3,505
From: looking for a flow bench so Brook and I can race
Re: Re: Re: Re: Re: Automatic shifting?
Originally posted by Aklaim
YES.....I'm 100% sure that when in 2, that is second gear and ONLY second gear. 95GRNZ tried it himself this morning. It is different between LT1 and LS1 cars. This is a LS1 forum, so I am speaking strictly on what it does on a LS1 tranny.
YES.....I'm 100% sure that when in 2, that is second gear and ONLY second gear. 95GRNZ tried it himself this morning. It is different between LT1 and LS1 cars. This is a LS1 forum, so I am speaking strictly on what it does on a LS1 tranny.
I wouldn't expect you to specify "on LS1" in the LS1 forum
. I was just asking if there was a differance.My next car is an LS1 and 6spd. I'll pick any damn gear i want.
I want to try this autocross stuff. An Ls1 with an aluminui block an top end power is what i need for autox
Registered User
Joined: Nov 2002
Posts: 281
From: South Texas
This question was asked in the November issue of GMHTP magazine 2002 to some guy (ask eric!) that has worked in GM overdrive trans for 7 years.
Q.- In a 700-R4 or 4L60E, is it better to shift manually in a drag race or to let the trans shift automatically?
A.- In a street/strip application, the trans should be set upto shift automatically in the "overdrive" or "drive" position. When you manually shift it, there's a delay in pressure rise. You push the lever and it won't respond right away because there's not enough line rise. You can burn the trans out shifting manually because there's not enought pressure to hold the clutches.
I had a friend who screwed his trans twice cuz he kept shifting manually in his a4. Plus he was using nitrous.
Q.- In a 700-R4 or 4L60E, is it better to shift manually in a drag race or to let the trans shift automatically?
A.- In a street/strip application, the trans should be set upto shift automatically in the "overdrive" or "drive" position. When you manually shift it, there's a delay in pressure rise. You push the lever and it won't respond right away because there's not enough line rise. You can burn the trans out shifting manually because there's not enought pressure to hold the clutches.
I had a friend who screwed his trans twice cuz he kept shifting manually in his a4. Plus he was using nitrous.
Registered User
Joined: Jan 2003
Posts: 602
From: San Jose, Ca
Is the 4l60e that makes sense. The tranny is elctronically controlled and when shifting there is a huge delay. But on a 700-r4 tranny, manual shifting is the best way to stayinyour power band. And I have had zero tranny problems, and i manually shift my 92 all the time.
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Joined: Dec 2002
Posts: 821
i ran into a guy with a 98 A4 Z28 (identical to mine except for an airbox lid) who claimed that shifting the 4L60E manually bought him a .19 sec improvemtn in the quarter. i dont know whether to believe this but he mentioned something about the stock programming shifting at 5700 RPM at WOT where as the motor is good up to the 6000 RPM redline. i haven't tried this because i just got my 98 and im still terrified to beat on it (wish i could say the same about my old LT1) is there any truth to this??????
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Joined: Aug 2001
Posts: 3,505
From: looking for a flow bench so Brook and I can race
from what i hear from 6spd guys- the best stock shiftpoint is the highest you can shift without hitting the rev limiter.
so yeah, if you can get another 200-300rpms out of it, it could help. manual upshifting isn't a big deal, down is
so yeah, if you can get another 200-300rpms out of it, it could help. manual upshifting isn't a big deal, down is
Registered User
Joined: Jul 2001
Posts: 603
From: I-L-L-I-N-O-I-S
I know lots of guys around here locally who have tested the D vs OD thing at the 1/4 mile track and there was NO difference in performance(ET's & MPH). And many guys on the other LS1 boards(LS1.com/LS1tech.com) have tested this out and come to the same conclusions.
Driving around in D will only eat up more gas bring on additional wear to the engine with the higher rpms around town. It's not really that bad, but I'd just recommend leaving it in OD unless you have a reason for putting the car in D.
BTW Trey, a stock-cammed LS1(with bolt-ons or not) should be shifted around 6,000 rpms which is right before the set 6,250 rev-limiter.
Mike
2002 M6 Z28
Driving around in D will only eat up more gas bring on additional wear to the engine with the higher rpms around town. It's not really that bad, but I'd just recommend leaving it in OD unless you have a reason for putting the car in D.
BTW Trey, a stock-cammed LS1(with bolt-ons or not) should be shifted around 6,000 rpms which is right before the set 6,250 rev-limiter.
Mike
2002 M6 Z28
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Joined: Jan 2002
Posts: 5,308
From: Oshawa - Home of the 5th-gen
Originally posted by 94ZRiCeKiLr
i ran into a guy with a 98 A4 Z28 (identical to mine except for an airbox lid) who claimed that shifting the 4L60E manually bought him a .19 sec improvement in the quarter .........................................i haven't tried this because i just got my 98 and im still terrified to beat on it (wish i could say the same about my old LT1) is there any truth to this??????
i ran into a guy with a 98 A4 Z28 (identical to mine except for an airbox lid) who claimed that shifting the 4L60E manually bought him a .19 sec improvement in the quarter .........................................i haven't tried this because i just got my 98 and im still terrified to beat on it (wish i could say the same about my old LT1) is there any truth to this??????
, and I've run back-to-back runs with greater than .19 second differences, and usually it all starts within the 60', not as much to do with shifting?
(although I do understand the fact that you want to rev the engine higher than ~5700/5800 rpm). Because of the delay in the shifts though, it's hard to know exactly when to "shift" so that the tranny shifts at the right time
. Transmissions like the TH350 in my '81 did benefit from manually shifting though. When I'd shift, the transmission would shift, so it was easy to hold the car in each gear and know it would shift when you wanted it to...................also, without a rev limiter was even better!Also, I don't like the argument that driving is D is going to be "hard on the car, hard on gas, etc., etc."
...........think about transmissions before we had the 700R4 --- there was no Over-Drive?! I know that it's there to provide better fuel economy, but I don't think it will make much difference until you're on the highway. And what about guys running with either stall converters or lower gears? Won't they also speed up the wear-out process throughout the driveline?!..............sometimes there's a price to pay for performance!
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Joined: Aug 2001
Posts: 3,505
From: looking for a flow bench so Brook and I can race
cptn-
I guess if you perfect it (cant really do it with a stock guage) 300rpms of powerband could really help...
as far asracing in D vs OD-
it wont make any performance differance! you weren't going into OD(well 95% of us) anyway. It might firm shifts up, i dont know. i never raced in OD to compare. Its not to reduce shifting time, but a firmer shift under loan is just healther for the trans from what i'd heard.
driving around in D vs OD-
I just do it to save the car another pointless shift. its going to come RIGHT back out of OD any in a few seconds anyway.
gas milage shouldn't really varry D vs OD IN THE CITY. At 40mph, there isn't much of an RPM differance. But the constant changes in speed (accel and decel) force shifts. less shifts is good.
I guess if you perfect it (cant really do it with a stock guage) 300rpms of powerband could really help...
as far asracing in D vs OD-
it wont make any performance differance! you weren't going into OD(well 95% of us) anyway
. It might firm shifts up, i dont know. i never raced in OD to compare. Its not to reduce shifting time, but a firmer shift under loan is just healther for the trans from what i'd heard.driving around in D vs OD-
I just do it to save the car another pointless shift. its going to come RIGHT back out of OD any in a few seconds anyway.
gas milage shouldn't really varry D vs OD IN THE CITY. At 40mph, there isn't much of an RPM differance. But the constant changes in speed (accel and decel) force shifts. less shifts is good.
Registered User
Joined: May 2003
Posts: 118
From: New Palestine, IN
I also agree with Trey on the D vs. OD issue. Personally, it kinda pisses me off when I'm just cruising and it wants to shift at 45mph or so into OD when it's just gonna downshift in a few secs anyway. My dad got his 97 Silverado brand new, and it now has just over 180,000 miles. Since he got it he has driven it in D until about 50mph, then shifted into OD. To this day he still has had 0 tranny problems, so it can't be hurting anything.
Registered User
Joined: Feb 2002
Posts: 241
From: Orlando, FL
Here's what the Owner's Manual has to say about all of this...
AUTOMATIC OVERDRIVE ((D)): This position is
for normal driving. If you need more power for passing,
and you’re:
Going less than about 35 mph (55 km/h), push your
accelerator pedal about halfway down.
Going about 35 mph (55 km/h) or more, push the
accelerator all the way down.
You’ll shift down to the next gear and have more power.
DRIVE (D): This position is also used for normal
driving, however, it offers more power and lower fuel
economy than AUTOMATIC OVERDRIVE ().
Here are some times you might choose DRIVE (D)
instead of AUTOMATIC OVERDRIVE ():
When driving on hilly, winding roads.
When towing a trailer, so there is less shifting
between gears.
When going down a steep hill.
SECOND (2): This position gives you more power but
lower fuel economy. You can use SECOND (2) on hills.
It can help control your speed as you go down steep
mountain roads, but then you would also want to use
your brakes off and on.
If you have a 5.7L V8 engine and manually
select SECOND (2) when you start the vehicle,
the transmission will drive (and stay) in second gear.
You may use this feature for reducing torque to the
rear wheels when you are trying to start your vehicle
from a stop on slippery road surfaces, or for preventing
the transmission from downshifting into FIRST (1) in
situations where a downshift would be undesirable.
NOTICE:
Don’t drive in SECOND (2) for more than
25 miles (40 km), or at speeds over 55 mph
(90 km/h), or you can damage your transmission.
Use AUTOMATIC OVERDRIVE () or
DRIVE (D) as much as possible.
Don’t shift into SECOND (2) unless you are going
slower than 65 mph (105 km/h), or you can
damage your engine.
FIRST (1): This position gives you even more power
(but lower fuel economy) than SECOND (2). You can
use it on very steep hills, or in deep snow or mud. If the
gearshift lever is put in FIRST (1) gear, the transmission
won’t shift into first gear until the vehicle is going
slow enough.
for normal driving. If you need more power for passing,
and you’re:
Going less than about 35 mph (55 km/h), push your
accelerator pedal about halfway down.
Going about 35 mph (55 km/h) or more, push the
accelerator all the way down.
You’ll shift down to the next gear and have more power.
DRIVE (D): This position is also used for normal
driving, however, it offers more power and lower fuel
economy than AUTOMATIC OVERDRIVE ().
Here are some times you might choose DRIVE (D)
instead of AUTOMATIC OVERDRIVE ():
When driving on hilly, winding roads.
When towing a trailer, so there is less shifting
between gears.
When going down a steep hill.
SECOND (2): This position gives you more power but
lower fuel economy. You can use SECOND (2) on hills.
It can help control your speed as you go down steep
mountain roads, but then you would also want to use
your brakes off and on.
If you have a 5.7L V8 engine and manually
select SECOND (2) when you start the vehicle,
the transmission will drive (and stay) in second gear.
You may use this feature for reducing torque to the
rear wheels when you are trying to start your vehicle
from a stop on slippery road surfaces, or for preventing
the transmission from downshifting into FIRST (1) in
situations where a downshift would be undesirable.
NOTICE:
Don’t drive in SECOND (2) for more than
25 miles (40 km), or at speeds over 55 mph
(90 km/h), or you can damage your transmission.
Use AUTOMATIC OVERDRIVE () or
DRIVE (D) as much as possible.
Don’t shift into SECOND (2) unless you are going
slower than 65 mph (105 km/h), or you can
damage your engine.
FIRST (1): This position gives you even more power
(but lower fuel economy) than SECOND (2). You can
use it on very steep hills, or in deep snow or mud. If the
gearshift lever is put in FIRST (1) gear, the transmission
won’t shift into first gear until the vehicle is going
slow enough.
Banned
Joined: Aug 2001
Posts: 3,505
From: looking for a flow bench so Brook and I can race
what a load of crap-
it doesn't give you ANY more power. my transmission can kick down to first on its own and have the same amount of power.
The point is, you dont want to shift a whole lot under load (ie hills, towing ect)
if you are only going to be in OD for .8 seconds and only lower rpms by 200, why even bother with all the additional wear and tear.
this is more common sence than tech
it doesn't give you ANY more power. my transmission can kick down to first on its own and have the same amount of power.
The point is, you dont want to shift a whole lot under load (ie hills, towing ect)
if you are only going to be in OD for .8 seconds and only lower rpms by 200, why even bother with all the additional wear and tear.
this is more common sence than tech
Registered User
Joined: Aug 2002
Posts: 1,719
From: Bay Area, CA
I am not accusing any one of lying but, I find it hard to believe the track times are the same when manually shifting and when just leaving it in drive. I think manually shifting the auto (at least the 4L60E) at the track would get a little bit higher times because when I manually up shift it takes a second for the car to shift into the next gear. The only time is manually shift it is when down shifting to slow down.
