LS3/480 convertor stall choices

[GTO Jack]

Hi All, new here. Getting ready to pull the trigger on a new LS3/480 with 6L80E 6 speed auto connect and cruise. I have a choice in
stall convertors, 2400 or 3000. this is just a street cruiser and no rear gears have been picked yet. Does anyone have experience with these
choices? I want to go with the 2400 as I don't need a loose convertor if It is not a dog off the line. Thanks.

[69cutlassrkt]

I don't have experience with the 6 speeds. I had a stock converter, a 2500 and a 3800 with a 4l60e. The 3800 was the most fun, it was always in the powerband when flooring it. That was with 2.78 rear gear. They were both aftermarket with a billet front cover and everything, not a stock one with the fins or whatever just bent more to increase stall speed.
I imagine with the 6L80e and that first gear it will not be a dog off the line. You could search on ls1tech and see what the G8 guys say. Ls1tech forum guys are more into racing than cruising though.

[ULTM8Z]

I'm running a 2500 rpm converter with 3.42 axle and it's also a street cruiser. ~450 hp gen1 383 SBC.

Feels no different than stock when doing normal driving (which is what I was shooting for since I want the car to have a factory feel to it)

But stand on it off the line and it's totally out of control. My TH700R4 has a 3.06 first gear too, as compared to a 4.02 in the 6L80E. So take that into account as well. The 2400 converter will be just fine for you IMO, but be careful on not over-gearing the rear axle. I probably would limit to 3.23-ish or 3.42-ish gear range.

[Hotwire]

Hi All, new here. Getting ready to pull the trigger on a new LS3/480 with 6L80E 6 speed auto connect and cruise. I have a choice in
stall convertors, 2400 or 3000. this is just a street cruiser and no rear gears have been picked yet. Does anyone have experience with these
choices? I want to go with the 2400 as I don't need a loose convertor if It is not a dog off the line. Thanks.

Look at the dyno graph of this engine. Where does the power pick up at? If you're not worried about MPG I would highly suggest going with the 3k stall. I ran a LS Hotcam in a smaller engine and there was no power below 3k. You could mat the throttle and it was like waiting for a turbo to spool.

[GTO Jack]

I'm running a 2500 rpm converter with 3.42 axle and it's also a street cruiser. ~450 hp gen1 383 SBC.

Feels no different than stock when doing normal driving (which is what I was shooting for since I want the car to have a factory feel to it)

But stand on it off the line and it's totally out of control. My TH700R4 has a 3.06 first gear too, as compared to a 4.02 in the 6L80E. So take that into account as well. The 2400 converter will be just fine for you IMO, but be careful on not over-gearing the rear axle. I probably would limit to 3.23-ish or 3.42-ish gear range.

That is what I am looking for. A stock feel. I want to feel the road thru my right foot. I want to gear it like the C6, an all around street or highway comfortable gear. Searching the net I find different information. Some say 2.56 and even 2.73. Don't know the factory truth there yet.

[GTO Jack]

Look at the dyno graph of this engine. Where does the power pick up at? If you're not worried about MPG I would highly suggest going with the 3k stall. I ran a LS Hotcam in a smaller engine and there was no power below 3k. You could mat the throttle and it was like waiting for a turbo to spool.

I have looked at the dyno and it seems it is similar to the 430hp except its 20-25 hp higher across the board. That is why I think GM gives you the choice in connect and cruise packages.

[ULTM8Z]

2.73 is too high. You already have a double OD in the transmission which means youd be lugging the engine at freeway speeds. I wouldn't go any lower then 3.23. And on the street you don't want to be crusing at engine rpm below the stall speed for too long.

[GTO Jack]

2.73 is too high. You already have a double OD in the transmission which means youd be lugging the engine at freeway speeds. I wouldn't go any lower then 3.23. And on the street you don't want to be crusing at engine rpm below the stall speed for too long.

This is the part I am struggling with. The trans has such a wide gearing gap. I will be running about a 27" tire, very close the what the Corvette ran and they claim a 2.56 or 2.73 gear if that's correct. Some other sites say 3.42 but most say the lower.

[ULTM8Z]

Maybe because the Corvettes are rated for very high top speed?

All I'm saying is for average street crusing with some spirited driving on occasion, you'll like the taller gears. Plus the 27" tire will make the 2.73 feel even higher. My tires are a hair under 26"

And again, you don't want to be crusing at below the stall speed on the converter for extended periods as it builds up a lot of hear. Though when in lock up mode that doesn't apply.

[79 Camaro]

I've used both Circle and Yank billet. 2800-3000 stall. They drive like a stocker until you floor it. I would do at least 3.42 or 3.73 gears. Get a big trans cooler. I have my tuner set up the tune so the trans doesn't shift past third until 40 mph. Keeps from lugging the engine.

[Vimes]

The Corvette ratios are 2.56 for the street and 2.73 for racing, so if your tire diameter is the same either will work for you. For the stall, IMO (and my experience is street machines that just see the strip for testing) the stall should be matched to the engine's torque rating, about 100RPM or so below peak torque at the bottom of the torque band if it's flat. And, it's entirely possible for the rear gearing to be too low (high numerically) for a 6L transmission. The 4.03 1st gear means putting too low a set will make 1st useless. Used to have a Tahoe that came with a 5.3 and 3.08s, and it was an absolute dog at any speed. I put 4.10s in, and 1st gear became useless. Never could get the tune to shift it right on the 1-2 shift. I put taller tires on which knocked it down to an effective 3.90 ratio, and it helped make 1st a usable gear, but ideally it needed 3.73s with a stock 31.6in stock height tire.

For a streetable car with a 6L trans and 27in diameter tires, I wouldn't go more than 3.08s, and ideally the 2.73. With that size tire and 2.73s the transmission will still lock up in 6th gear just fine on the highway (it does in the Corvette) and it will scoot down the road about like a 4L60E with 3.73s in 1st gear. Go higher than 3.08s on 27in tires, and you may as well not have 1st gear.

Minor note - on a board I used to post to, it was discovered that a 4L60E torque converter for a 4.3L has approximately 200-300RPM more stall than the 4L60E torque converter for a 5.7L, when the 4.3L torque converter is installed behind a 5.7L. The 6L50E transmission used behind the 3.6L Camaro might do the same, but it would be up to someone else to give it a try and see if it'll fit and what the effect was.

[GTO Jack]

Well I did some research today. A couple years ago I bought a used Hellcat. Sold it when they were getting good money. It comes stock with a 2.62 rear gear on a 28.7" tire. It has a 4.71 first gear. A popular upgrade is a 3.09 from a SRT 1320 or Demon. It had the 3.09 in it most of the time. It did everything very well. Both the Hellcat and the 6L80 have a .67 final overdrive. The Hellcat would hit 8th gear [.67] at 60mph and have power at 1200rpm. So now I am trying to figure out what a .67 trans with a 3.09 rear and 28.7" tire computes to running a .67 trans with a ? rear and 27" to maybe 28" tire? And I am running a Ford 9 inch so gear choices are 3.00 then it jumps to 3.25, then 3.33 and 3.40 and so on.

[Hotwire]

Use this calculator, you can plug in all the gears, rear gear, tire sizes, etc. Then you can compare different setups. I love the different tables it shows, used it with my setup to get a feel for best shift rpms.

https://www.blocklayer.com/rpm-gear.aspx