Ok, well i am not sure about lock up at WOT, i didnt think i wanted it to lock at WOT or am unsure kind of whats going on here. I just want the verter to lock up at cruise speeds around 40 mph so i can save some MPG around town when im not having a lead foot. Is this is same locking stuff at WOT or totally different? And 3800 2.1 still feelin good?

 

TireSmoke, you should be a mod in this section. You know your stuff and its very help. thanks man for all the time your putting into these long posts, you da man. And thanks everyone else whos chiming in, its great help and i appreciate your time to help!

 

I'm going with the SS3800 2.5STR...since i'm staying with stock gears (3.23). If I went to 3.73 i'd probably want a lower STR around 2.0.

 

ah, what tires are you running?

 

Superman - locking up at cruise is controlled by the PCM to get you mileage. Locking up at WOT does the same thing (for more power instead of mileage), but you need to install a switch so you force it to lock.

Tiresmoke - I am enjoying this discussion. Hopefully others are learning from it as well, and we have not taken this thread too off topic. I have a question about your explanation, I have never locked my car at WOT, and only know one person that has. When he locked it, I don't recall a bog, just felt like it pulled harder. Why would it bog? Your engine is up at say 4500, why wouldn't it lock to close to that (I could see a few hundred rpm loss initially, but not 1000+ loss like you suggest)?

When the car locks at cruise, you loose a lot of rpm, but I assume that is because you not at a fast rate of speed, and the rpm is not at 4500 so the converter is slipping more at the lower RPM. But at closer to or above the stall speed, the converter is not going to be slipping as much, so wouldn't your rpms stay pretty high? As well as the fact that everything is at a high rate of speed and would want to stay that way.

???

 

I just talked to my friend, he said he would lock his after shift extension, when it went into coupling...

 

Ok, so for max street potential, how would i want it tuned to lock up? Do i get it tuned 2 different ways, one for WOT and one for cruise or is it the same tune? What would be a good lock up and best tune for it for my wants? Thanks alot guys, this is a very informative thread!

 

This thread is awesome... ::: thread tools, subsribe to this thread ::: now i'm just gonna sit back with a and enjoy! keep the info coming!

 

Not 2 tunes. You wire a switch that you will throw when you want it to lock at WOT. Other then that you let the PCM control it all an lock it and unlock it when needed at cruise.

 

Ok, so do i want it to lock at WOT? Will this give me more power/make me faster? When do i want to engage this switch and when will i want to turn it off? thanks!

 

Right now stock but it will have a 315 drag radial.

 

Yep, I see exactly what you're thinking about the converter not slipping as much at high rpm, but it's actually doing more slipping than you think, even up near 4500rpm. Have a look at this:

http://www.geocities.com/z_design_st...ion_z28_6.html

This is an interesting little thing to play around with, if you plug in the 4L60E gear ratios, 3.06, 1.75, 1.00, .70. You might notice that, according to this chart, your rpm after a shift is down around ~3400rpm (stock shift points) . But that doesn't make sense, this says we're at 3500 rpm after a shift, when everyone with a stalled A4 knows they're really about 4400-4800 (or higher). This is basically "shift extension" at work, which is a result of the converter slipping, even up that high in the range, and allowing the engine rpm to turn higher, and, thus, output more torque/hp to the transmission and consequently to the wheels. In reality, the converter IS allowing less slip up higher in the rev range, but we have to remember, that a 3800stall will allow (roughly, in theory), 3800rpm of slippage! While the car is standing at 0mph! So it's not inconceivable to think that it would still be slipping 1000-2000rpm on the topend. Which means, as soon as you lock, you drop the exact # of rpms that the converter is "slipping". For most people, it would be about a 1200-1500rpm loss (again this depends on specific converter, but in general).

So play around with that gear calculator, and it will show you exactly what rpm your car would be at with the converter locked. The important thing to remember is that those values are with a *locked* converter, and if you pay close attention, you'll see that it's not the real values you see on the street under real driving (especially with a stalled car).

Earlier, I was saying that if you locked immediately after the 2-3 shift (just as you enter 3rd gear), your rpms would drop down to ~3400 rpm with 3.23's. This of course would really kill the car's acceleration, as you'd be at WOT at 3400rpm...... try it in a 6speed, and you'll see that the car goes, but... not quite as fast. That's why I was saying, 80mph is too early to lock. If you waited until 105mph or so, you'd be high enough in the rpm range that once you locked, you wouldn't fall too far below peak torque.

This concept is kind of illustrated when you're on the highway, after accelerating up to speed, you hit 4th gear, ease off the throttle a bit, and then you feel that little "blip" as the converter locks and drags the rpms down from ~2000 to 1500 (or thereabouts), and it almost feels as if you've gone into a 5th gear, and the car doesn't want to accelerate as much. This is exactly what would occur on the topend, only it would be more like a 1000+rpm drop as opposed to 500.

Nowww, this all changes if your car had 4.10's.... you COULD see a noticeable gain if you locked in 3rd gear, but only under a *very* specific set of circumstances where it would be worth it. You could lock as early as 80mph without bogging the car. This is, of course, providing that you don't trap higher than ~112 mph, because then you'd have to go into 4th, which couldn't be done on a locked trans (not more than a couple times at least!). So if the race goes above 112mph, you're outta luck (or due for a rebuild!).

Why does this work on 4.10's, and not so much on 3.23's or 3.42's? Simply because you get into a favorable condition for locking earlier with the 4.10's. With 3.23's, as stated, it's only above 105mph that you can really see benefits, and, for most bolt on cars, there's not much of a difference.... not enough of a difference to validate putting that type of wear on the converter.

Furthermore, if we look at a reasonable ~3600/2.1 STR or less.... you're losing very little on the topend. This is a completely different story if you have a 5500 stall Grand National, that's bleeding HP off the topend like crazy. Those guys, on a high horsepower drag car, could easily be losing closer to 100hp to the wheels (!), but for the type of situation we're looking at here, it's just a few hp, and only applied over the last 1 or 2 seconds of a 1/4 mile run.

It basically just boils down to, it's not really worth the additional $ on the beefed up converter clutches, or the extra wear on the converter, or the transmission, or the extra computer tuning, for nearly 0 gain on a street car, to go the whole lockup route. Like I was saying before, the cars that *do* do this can lock up after the launch, and run 80% of the track locked, but then you're dealing with a monster transmission to accomplish the shifting on a locked verter.

 

To summarize everything for Superman09:

In my opinion, I would not recommend trying to do the WOT locking, as you increase your chances of a mechanical failure, for a gain that is very very small to 0, on a 3.23 car.

If you pick a 2.5-2.9STR converter, yes, you are losing a decent amount of power on top. If you pick a 2.0-2.1STR converter, from a reputable supplier, I would foresee either an unchanged trap speed or a small gain (.5mph+) in trap speed, which has been done often on a moderate STR/moderate stall.

Part throttle locking, you definitely want, of course.

 

should look into yank they have some new stalls, not quit 3800 but a damn good price https://ls1tech.com/forums/automatic-transmission/446398-yank-has-new-low-pricing-ls1tech-members.html, dont buy an old used stock core get a new one, my converter was just under 700 so it is not that much more, believe me it will last a long time my dad still have his YANK TT3000 with over 600 passes on it and it is still performing like brand new, in the fall he pulled a 1.56 with just a cam only car and 3000 stall...i know you got your mind set but just think it over....

 

Yes, already said this i dont no how many times, not to be rude, but i AM already going with a Fuddle. There customer service is great. there prices are the best out there. and there converters are top notch! Even if i do have any problems, im not worried, i know Fuddle will help me out and thats why im buying from them. So no ones answered....... Agree that 3800 2.1 str is the one for me?

 

Those are 278mm converters, you would be much better off with a 245mm. I think Superman is making a wise choice getting a Fuddle.

And 3800 would be good for you Superman.

 

Not quite 3800? 2800 to 3800 is a huge difference stall wise. not even close, man.

Go with the smaller 245, much better for performance. You're going with the bigger one, right, the HP? I agres with The Sad, 3800 should be good for what you're doing.

 

Yea, im going with the HP/Street one so it will still hold farther down the road when i mod more. Thanks guys. How are the stock trannys holding up to bigger stalls? Mise well keep this thread flowing with some more info. Should i totally take torque management out? And if i do how much time will i be on before she blows?

 

Leave TM, and get a bigger cooler.

 

Ive read that TM leaves out a lot of its potential and it should be fully removed or all of it, but then it will stress your trans. Should i wait until i have enough money so when i pull the trans to install the verter i can just upgrade the trans or will it be fine with big verter on stock trans?