Mike Morris

iTrader: (55)

I have a 3800 stall and a shift kit. Works great and shifts decent. Best mod to that car by far.

thunderstruck507

iTrader: (18)

my car isn't sloppy at all, but we rebuilt the trans with some good parts too

on street tires it will bark 2nd and try to chirp 3rd, on drag radials it just gets a small chirp on 2nd

everything is firm but not jerky and brutal, just feels very positive on part throttle shifts, only difference is it revs to around 1800-2000rpm from stops in my heavier car, pulling hills puts it up around 2500-3000rpm at speeds under 40mph

I didn't notice any difference in fuel mileage neither in town nor highway...if anything it was about as much difference as driving peppy for a week and being a granny for a week, but mix up driving style and it becomes irrelevant

I would never go back to stock...I'd rather sell my car

Sticks n Stones

I have the ability to measure gas mileage down to the ninth degree: I drive 75 miles a day on my commute, during off peak hours so traffic jams are a non issue, with 36 of those miles freeway at 68mph (fastest you can go without risking a ticket in Washington) and the remaining 39 miles split equally between rural 55mph with a few stoplights, and stop n go intown driving. I measure it every gas change and document it.

Around town only mileage went from 17 down to 13-14, rural and freeway both went up 2-3mpg, offsetting the drop in the intown mileage to where I'm back where I was pre-stall-- 20.5mpg overall average. Taking off from a stop, my car doesnt move an inch until I hit 1,900 (when trans hot) to 2,100 (when trans cold). No idea why it's different hot to cold, but it is. Dex VI trans fluid btw.

From a stop if I give it a little punch (1/4 throttle?) just to get it moving decently it flashes to 2500-2800rpms. My trans has a 75% TM removed trans ECU (trans has a seperate ECU on 4L65E transmissions) and at WOT will even chirp the 2-3 shift with my sticky tires on.

thunderstruck507

iTrader: (18)

yours stall sounds a lot looser than mine, what is it? vigilante? tci?

my car will start moving at idle and if I'm granny driving (ie accelerating with normal traffic) a normal stop to go could be done at well under 2000rpm

if you are easy with it, a person who didn't know better would have no reason to assume the car didn't come that way...until you ease upwards of 25-30% tps and anything close to half or more hits 3600 pretty quick

to contrast a buddy had a 4000 vig and that had an aweful slipping clutch feeling from a stop and on even mild hills, but it ripped hard at WOT

senicalj4579

iTrader: (41)

On yanks website they say that one (maybe more) of their competitors dont advertise the true stall speed for the converters. Maybe that has something to do with it? I deffinatly will not cheap out on a converter. From what I read and learned I like the sounds of yank.

01ssreda4

iTrader: (96)

Here's an old thread I had put together that may help.

https://ls1tech.com/forums/multimedi...uge-shots.html

jdiddyws6

iTrader: (5)

Converter is probably the best mod for the buck. A definite requirement if you plan on turning some serious times in any auto. To me (and probably most here) the "mph loss" that does not always occur is well worth the ability to get into the power band immediately. As I said in the other thread, if roll racing is that serious to you, you can get a triple disk lock up converter that will support WOT lockup, and you will have ~100% efficiency.

Sticks n Stones

And he has a "loose" converter.
Got a convertor capable of that, but telling the trans when to do that is a whole different story! My tuner should be able to get it to lock up. ?

A week after the install, my wife left my car on the side of the road a block from my house and walked back home. She then woke me up (I was working graveyards) and said "There's something wrong with your transmission. I think it's going out because it's slipping bad when I hit the gas."

thunderstruck507

iTrader: (18)

that was pretty much my point, you can get a stall that suites your driving style and needs

they aren't all loose and sloppy feeling, just depends how much you want to compromise

jdiddyws6

iTrader: (5)

Yeah, your tuner should be able to get it to lock up on demand. And also, set a gear/mph for it to lock up in third and OD. Sorry to hear about your wife's misfortune.

jdiddyws6

iTrader: (5)

This.

01ssreda4

iTrader: (96)

Once again you are confused. Straight from the auto trans sticky:

What makes some torque convertors "loose"?
The greater the STR, the tigher the stall will be. For example a 3200rpm 2.2str stall will be looser than a 3200rpm 2.5str stall. Also, as the rpm rating increases, so does the "looseness". For example a 3600rpm 2.5str stall will be looser than a 3200rpm 2.5str stall.

01SuperSport

iTrader: (7)

Don't worry about it OP you can't always be the fastest car. Just put a stall in or if it REALLY bugs you then sell the car or do a swap.

Sticks n Stones

Think I'll stick with Coolaid's version, thank you very much: I discussed it with Yank and Pheonix Performance and they verified his interpretation is correct:
http://www.ls1gto.com/forums/showthr...rter+explained

"Generally, the higher the STR number the more it multiplies torque at the starting line or from a dig at a sacrifice of top end efficiency. The lower the STR, the more it multiplies torque over a longer period of time/longer distance at a sacrifice of short term large torque multiplication. Think of a high STR as a shell of buckshot that hits harder close range/hits all at once off the line and a lower STR like a 9mm that hits decent but effective at a longer range. So if dig racing or strip launching is important to you a higher STR will benefit, if rolls or trap speeds are more important to you than a lower STR will fit. STR range is usually 1.8-2.5.


High STR can also make the car hard to hook up. This is how it works in the first few feet:

Lets say we make 450 ft/lbs of torque at the flywheel @ 4,200 RPM. We add in a 4,200 stall, one with a tight/low 1.8 STR and one with a loose/high 2.5 STR. The STR becomes a mulitplier:

450 x 1.8 = 810 ft/lbs of torque at the trans input shaft when the car flash stalls to 4,200 RPM from a dead stop.

450 x 2.5 = 1,125 ft/lbs of torque at the trans input shaft when the car flash stalls to 4,200 RPM from a dead stop.

See why the higher STR could be harder to hook up consistently? Like stated, the other difference is that the lower STR verter will keep that torque multiplied for a longer time than the big STR. So its all about where you want your power and where you use it the most. If you have trouble hooking up for a reason you cant solve with DRs or suspension, maybe consider a lower STR to get the car off the line.

How about the guy who wants a "driveability" converter in the 3,200-3,600 range that hooks up decent? He may want to still consider a lower STR depending on where his cam makes its power. I.E. lets say we have a 3,400 stall but a big cam that starts the meat of its power band around 4,200-4,400. In that case a lower STR (like 1.8) will still multiply some torque by the time it gets to that engine speed where as a big STR (2.5) combo'd on that same cam will be less efficient and have far less multiplication by the time the car hits that engine speed.

Nitrous and Boost are also better mated to a lower STR converter. You'll often here people saying not to run too large of an STR with nitrous because it will "blow through" the converter. The big STR verters are simply too loose and nitrous would be wasted through the converters slipping action. I.E your going to become good friends with the rev limiter. As far as boost, you want it to build as much pressure as possible in the shortest amount of time so you dont want the engine to flash up so fast before it has a chance to build boost and boosted cars are usually top end cars and low STR verters are better suited for that (once again because of the torque multiplication over a longer period of time). Also boosted applications make a ton of low end torque and a high STR converter could aggravate a traction issue.

Shift extension is another variable to consider. A higher STR verter will give you a higher shift extension (the point your engine RPMs fall to after a shift). A higher shift extension may be more beneficial to those with a monster cam that builds all of its power up high. Example: My 2.5 verters shift extension right now is 5,000RPM. Meaning, when the car shifts the RPMs only fall to 5k and climb back up. Technically, my car is a good example of a mis-match currently since it has the stock cam. However, I spec'd the converter for a big 240+ duration can and dont expect to have the stocker in there forever.

Another thing to consider is high STR converters get their high multiplication from slippage. Slippage causes heat. Heat causes 90% of automatics to fail. I wouldnt recommend a high STR verter for a DD car. Example: I have a ~2.5 STR loose 4,200 stall in my bolt on Goat. Built trans, Derale deep pan w/ cooling tubes, stainless braided -6AN trans lines going to a top of the line Derale Atomic Cool 400cfm fan equipped trans cooler and DEX VI (better heat tolerance than DEX III). My trans cooler fan is auto on @ 180'F and off @ 170'F and lets just say once the fluid hits 180 (and it will) I never hear the fan turn off. Its not uncommon for me to see 200'F temps cruising around town not even hammering on it. Comparatively, my buddies '00 Camaro that is lighter, has a tight 1.8 STR 3,400 verter with a basic B&M supercooler as his only cooling mod sees 170'-175'F in 100'F ambiant temps all day long."

senicalj4579

iTrader: (41)

Im getting some really good info here guys keep on debating

thunderstruck507

iTrader: (18)

well my yank ss3600 is a 2.5 str

tight to me, and my temps stay around 150-170* with a stacked plate cooler...works for me

seems converters are difficult to compare on paper

Sticks n Stones

Agreed. I was talking to a General Electric turbine fluid dynamics engineer a few minutes ago about just this subject: He said that given 10 million dollars and 2 years he could design the ultimate torque converter- most efficient, barely any heat created, light, strong as hell with a nice low STR but - with the push of a button - it could become a high STR race converter.

But it would only work properly on a engine with the parameters he designed it for. Any other build would be "less than optimal" and would approach the generalized parameters in use right now. He did say that torque converter stator's and vanes should look very very similiar to turbine engine PTO hot section blades - yet they don't. (air compresses, trans fluid does not) Must be a cost issue.

senicalj4579

iTrader: (41)

What size cooler and where is it mounted?

RED94Z28

iTrader: (1)

Sounds like an interesting discussion NOT. I'm sorry but most of the engineers i know who work for companies like CAT, couldnt figure out how to design a ball point pen, they all run there mouth after the fact of how something is so easy to design they just cant close the deal. Sounds like your buddy the " electric turbine fluid dynamics engineer" is a douche bag who prolly knows nothing of the subject who's just running his **** holster to tools like you who believe everything they say. Sound about right???

Sticks n Stones

Wow you're a pessimistic a*hole arent you? The engineer I was talking to was one of the head engineers responsible for the design of the highest tech, most expensive aircraft engine in the world. A multi-billion dollar engine design. And a car guy who knows exactly how torque converters work.

But you, the internet warrior who knows everything, obviously knows more about it than him. Want a job? I'm sure Rolls Royce or GE would snap your superior intellect up in a heartbeat and pay you the millions that a head engineer makes without a second thought.