Why aren't gear swaps helping stalled car's?
10-10-2009, 01:48 PM
#1
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Why aren't gear swaps helping stalled car's? I have done a lot of searching on this and it seem's that stalled car's gain almost nothing from gear's. Maybe a 10th, but thats about it. And that seem's to include even the 2.73 geared cars.
Here's why I ask.
I have a 2.73 gear's with a rather small stall, [3000] which was not too bad for a stock internal ls-1.
But now I have added a GM Hotcam, which isn't building a whole lotta tq before 3600 rpm. It peaks at 3800 at 380 #'s and stay's pretty much flat up to 6000 .
I was thinking about swapping from my 2.73's to 3.42's or even 3.73's to get my car into the powerband quicker, and also it would seem as though the mechanical advantage of lower gears would aid acceleration.
But from what I have seen in my search's, this dosn't seem to be the case.
Maybe a bigger stall would be the answer.
Yanks got one w/a 3600 rating that look's like it may help much more then the gear swap.
If any of you guy's have been in my spot let me know what you did and the results gained from your choice.
Thanks much.
Here's why I ask.
I have a 2.73 gear's with a rather small stall, [3000] which was not too bad for a stock internal ls-1.
But now I have added a GM Hotcam, which isn't building a whole lotta tq before 3600 rpm. It peaks at 3800 at 380 #'s and stay's pretty much flat up to 6000 .
I was thinking about swapping from my 2.73's to 3.42's or even 3.73's to get my car into the powerband quicker, and also it would seem as though the mechanical advantage of lower gears would aid acceleration.
But from what I have seen in my search's, this dosn't seem to be the case.
Maybe a bigger stall would be the answer.
Yanks got one w/a 3600 rating that look's like it may help much more then the gear swap.
If any of you guy's have been in my spot let me know what you did and the results gained from your choice.
Thanks much.
10-10-2009, 01:56 PM
#3
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One benefit of the 3.42-3.73 gears is that it will make a stalled car more street friendly. Your right though, in many cases a gear change will only help a small amount. In your case though with the 2.73s your going to see and feel a nice improvement.
10-10-2009, 02:48 PM
#5
Recently had 3k stall and a 2.73 to 3.42 gear change done at the same time and can definitely tell there is alot more off "the line". Car has lid\headers but otherwise is stock.
Sorry but I have no actual before or after track times to verify that it is faster.
Sorry but I have no actual before or after track times to verify that it is faster.
10-10-2009, 05:19 PM
#6
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10-10-2009, 06:01 PM
#7
going from 2.73's to 3.73's won't show an improvement if the tires are spinning. I can promise you will see a nice gain even with a stall, but you need traction to make it happen bottom line.
^*I believe 01ssreda4 had a 3200 stall and he is now restalling it to 4k.
^*I believe 01ssreda4 had a 3200 stall and he is now restalling it to 4k.
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10-10-2009, 06:10 PM
#8
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My question is why aren't stalled cars seeing almost no improvement when they switch to lower gears.
It seem's like gear's should help do to the mechanical advantage.
10-10-2009, 06:34 PM
#9
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Gears will definetely help e.t. - I'm not sure where you are getting this idea that every body with a stall gains nothing from gears...
The most important thing you get out of both a stall and gears is that you are in your powerband quicker, as well as spending less time in the weak part of your engines rpm range.
But they both work together, for example installing gears only may pick you up .3 seconds. Installing a stall after that might pick you up .1 to .2seconds.
On the flip side installing the stall first may net you .3 seconds, and installing the gears second might get you .1 to .2 seconds
Of course this is all assuming you get traction. Its not uncommon to see someone add a stall and gears, then have issues with spinning.
The most important thing you get out of both a stall and gears is that you are in your powerband quicker, as well as spending less time in the weak part of your engines rpm range.
But they both work together, for example installing gears only may pick you up .3 seconds. Installing a stall after that might pick you up .1 to .2seconds.
On the flip side installing the stall first may net you .3 seconds, and installing the gears second might get you .1 to .2 seconds
Of course this is all assuming you get traction. Its not uncommon to see someone add a stall and gears, then have issues with spinning.
10-10-2009, 06:49 PM
#10
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Gears will definetely help e.t. - I'm not sure where you are getting this idea that every body with a stall gains nothing from gears...
The most important thing you get out of both a stall and gears is that you are in your powerband quicker, as well as spending less time in the weak part of your engines rpm range.
But they both work together, for example installing gears only may pick you up .3 seconds. Installing a stall after that might pick you up .1 to .2seconds.
On the flip side installing the stall first may net you .3 seconds, and installing the gears second might get you .1 to .2 seconds
Of course this is all assuming you get traction. Its not uncommon to see someone add a stall and gears, then have issues with spinning.
The most important thing you get out of both a stall and gears is that you are in your powerband quicker, as well as spending less time in the weak part of your engines rpm range.
But they both work together, for example installing gears only may pick you up .3 seconds. Installing a stall after that might pick you up .1 to .2seconds.
On the flip side installing the stall first may net you .3 seconds, and installing the gears second might get you .1 to .2 seconds
Of course this is all assuming you get traction. Its not uncommon to see someone add a stall and gears, then have issues with spinning.
Regardless of gear's, whether it's 2.73's or 3.42's the stall will alway's net you a gain of up to 1/2 second or more. [ w/dr's]
However, once that stall is in, swapping out those 2.73's for those 3.42's will gain at most maybe a tenth, or just a hair more.
If you do a search, you will see that I am not just making this up.
I have read dozen's of post's on this.
10-10-2009, 07:29 PM
#12
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And that's why I am thinking that a bigger stall for my cammed car might be of more benefit then a gear swap.
10-10-2009, 07:52 PM
#13
My current converter flashes to about 4400, very streetable. I wouldn't be afraid of something bigger than a 3600 for your car. My next converter will more than likely be a PI 5 disc, locking the conveter on the 2-3 shift definately woke my car up. Nice gains in both ET & MPH.
10-10-2009, 07:56 PM
#14
4000 converter IMO is PERFECT for these cars.. 3600 is the SMALLEST I would put in ANY ls1 car.. Whether it be a bone stock to the filter or a H/C nitrous car. I actually prefer a bit of a loose 4000.
The difference in changing gears out will be minimal.. A change in stall speed will be a HUGE difference.
Step up to a 3600 or 4000, you will not be disappointed.
If you want some 3.23s I have some I will sell for cheap.
The difference in changing gears out will be minimal.. A change in stall speed will be a HUGE difference.
Step up to a 3600 or 4000, you will not be disappointed.
If you want some 3.23s I have some I will sell for cheap.
10-10-2009, 07:58 PM
#15
My current converter flashes to about 4400, very streetable. I wouldn't be afraid of something bigger than a 3600 for your car. My next converter will more than likely be a PI 5 disc, locking the conveter on the 2-3 shift definately woke my car up. Nice gains in both ET & MPH.
I have heard locking it will help in the 1/4.. But am I going to see anything in the 1/8? I have heard it puts more stress on the trans. and if it is not going to help there is no need in blowing the transmission for nothing.
10-10-2009, 08:42 PM
#16
Plenty of street miles in addition to the racing I did before I broke stuff in the rear. My trans builder & tuner wouldn't have suggested it if it was going to break things. My 1/8 ET and MPH was better as well after the change. But, I believe it would be dependent on how soon you see a 2-3 shift prior to the 1/8. My 2-3 shift comes right about 85 MPH, and I make about 100 MPH in the 1/8.
10-10-2009, 08:48 PM
#17
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Could the results you are finding be because gears (3.42+) give you the most advantage coming off the line (first 60')...just to get the weight rolling??? This is essentially the same benefit as a stall...right????
Since you already have a 3000 stall, It seems unlikely that you will see more of an ET reduction than going with a taller gear...in your case.
Since you already have a 3000 stall, It seems unlikely that you will see more of an ET reduction than going with a taller gear...in your case.
10-10-2009, 08:50 PM
#18
Plenty of street miles in addition to the racing I did before I broke stuff in the rear. My trans builder & tuner wouldn't have suggested it if it was going to break things. My 1/8 ET and MPH was better as well after the change. But, I believe it would be dependent on how soon you see a 2-3 shift prior to the 1/8. My 2-3 shift comes right about 85 MPH, and I make about 100 MPH in the 1/8.
Thanks for the clarification.
10-10-2009, 08:58 PM
#19
Could the results you are finding be because gears (3.42+) give you the most advantage coming off the line (first 60')...just to get the weight rolling??? This is essentially the same benefit as a stall...right????
Since you already have a 3000 stall, It seems unlikely that you will see more of an ET reduction than going with a taller gear...in your case.
Since you already have a 3000 stall, It seems unlikely that you will see more of an ET reduction than going with a taller gear...in your case.
10-10-2009, 09:24 PM
#20
If you're gonna lock it, it needs to be at a speed that keeps you above your shift extension RPM. Lock it to early and it's like shifting into to high of a gear.
In the cases I've seen that it actually work on, it really only noticeably benefited MPH because it happens so late in the run.
In the cases I've seen that it actually work on, it really only noticeably benefited MPH because it happens so late in the run.