PRO'S AND CON'S on a 4l80E
I guess a big enough converter would make up for it... but you would have to be making SERIOUS power to warrant the swap IMO... it takes more Hp to turn the big bitch over... plus the first gear issue... Which is probably why the TH400 guys havent complained... if you are making enough power to need the swap, the extra loss wouldnt be noticeable IMO...
Not necessarily. I mean, yes, I'm heads/cam/spray, so it's worth it for me. But look at it from all viewpoints. It's also worth the power loss because it's so tough. Most of us would trade some power for more reliability over these junk 4L60e's, and most of us need overdrive. It's the only smart option.
Also, the 4L60e can be a turd beause of the wide spread between 1st and 2nd. I mean, the 1st gear on the 60 is TOO LOW for the times we need. Even a stock car with a decent stall will run better times with that taller first gear.
Here's the ratios, for those who want to chime in:
Gear--------1-------2--------3------OD
4L60e-----3.06----1.63-----1.00-----0.70
4L80e-----2.48----1.48-----1.00-----0.75
Also, the 4L60e can be a turd beause of the wide spread between 1st and 2nd. I mean, the 1st gear on the 60 is TOO LOW for the times we need. Even a stock car with a decent stall will run better times with that taller first gear.
Here's the ratios, for those who want to chime in:
Gear--------1-------2--------3------OD
4L60e-----3.06----1.63-----1.00-----0.70
4L80e-----2.48----1.48-----1.00-----0.75
Originally Posted by 8a8mfh
Thats not really possible. I can see the output shaft sticking out of the end of the tail housing. If your tail housing was 5" longer the yoke would never reach the output shaft. Plus the stock tail housing is not much more than 5".
Jim
Originally Posted by LS1rulz
Also, the 4L60e can be a turd beause of the wide spread between 1st and 2nd. I mean, the 1st gear on the 60 is TOO LOW for the times we need. Even a stock car with a decent stall will run better times with that taller first gear.
There's about a 20% difference in first gear from 2.48 to 3.06, so let's look at a 2.73 and 3.23 car. I have never seen a stock 2.73 car that is faster than stock 3.23 with any size stall from 2800 to 4400 when both cars have adequate tires and the only difference is the rear gear. You'll see .05 -.1 in the 60' with 3.23s depending upon the stall size.
The same is true when going from 3.23s to 3.73s. Just about everyone with a stall who is not traction limited gains about .1 in the quarter mile with .05 coming in the 60'. I've never seen anyone run slower, so long as they don't run out of room at the top of third.
If you're in the high HP leagues and running a restricted tire size, I could see where the longer 1st gear becomes an issue. Its the classic debate of going with a PG v. TH350/400.
No need to guess. Just look at the stock internal top 50 list.
https://ls1tech.com/forums/drag-racing-results/628613-quickest-stock-internals-list-11-79-bump.html
On an eyeball basis, roughly 40 of the cars are A4s. Not a single one has 2.73 gears.
https://ls1tech.com/forums/drag-racing-results/628613-quickest-stock-internals-list-11-79-bump.html
On an eyeball basis, roughly 40 of the cars are A4s. Not a single one has 2.73 gears.
LS1 Tech Stories
The Best V8 Stories One Small Block at Time
6 Common C5 Corvette Failures and What's Involved In Repairing Them
Pouria Savadkouei
Retro Modern Bandit Pontiac Trans AM Comes With Burt Reynolds' Autograph
Verdad Gallardo
Top 10 Greatest Cadillac V Series Performance Models Ever, Ranked
Pouria Savadkouei
Top 10 Most Powerful Chevy Trucks Ever Made!
Hennessey's New Supercharged Silverado ZR2 Has 700 HP
Verdad Gallardo
Coachbuilt N2A Anteros Is an LS2-Powered C6 Corvette In Italian Clothes
Verdad Gallardo
Awesome K5 Blazer Restomod Comes With C7 Corvette Power
Verdad Gallardo
10 Camaros You Should Never Buy
10 LS Engine Myths That Refuse to Die
Verdad Gallardo
How about a parts list for a 4L80e swap into a 4L60e equipped LS1 car...
-built 4L80e trans
-Driveshaft? Which one? 300m from FLT? Somewhere else?
-converter-which would you reccommend? N20 is probably in the future..
-Cross member? Torque arm? Wiring harness? Shift linkage? Anything>\?
-built 4L80e trans
-Driveshaft? Which one? 300m from FLT? Somewhere else?
-converter-which would you reccommend? N20 is probably in the future..
-Cross member? Torque arm? Wiring harness? Shift linkage? Anything>\?
Originally Posted by LS1rulz
Remind me of where the 2.73 gears came in. I'm not talking about them. I'm talking about the same gear ratio as the TH400.
The point is that 60' time is a direct function of 1st gear if we hold all other things (e.g. stall size and motor mods) constant. If using a lower 1st gear ratio (i.e. 2.48 vs 3.06) improved 60' time, we would see that a 2.73 car would have a lower 60' time than a car with 3.23s or higher gear. The fact is that in a properly set-up car, the lower 2.48 gear is of no benefit until you hit very high HP levels, levels far beyond heads/cam/mild spray.
I do understand the value of close shift ratios. The exception I would make to the above is if you are willing to shift into 4th and use a much higher gear ratios. You could take advantage of the shorter shift drops by running 4.56 gears to make up for the long first gear, but that would suck in a street car that sees much highway use.
BTW, you can get a higher first gear as an option on a TH400 from some builders.
Yeah, I know.
My interest in this comes in that I'm trying to decide between 3.42 and 3.73 for my upcoming 4L80e swap. I know the 3.73 may be a little better at the track, but is 0.1sec worth the loss in gas mileage? I'm stuck on that dilemma.
My interest in this comes in that I'm trying to decide between 3.42 and 3.73 for my upcoming 4L80e swap. I know the 3.73 may be a little better at the track, but is 0.1sec worth the loss in gas mileage? I'm stuck on that dilemma.
i have 3.42's they are a nice compromise, but even with 3.73 you could get into 135mph trap speed territory without being terribly tough on rpm's
i run about 2500rpms locked up at 75mph in OD
i run about 2500rpms locked up at 75mph in OD
