A buddy of mine is fixing up an a4 95z. He want's to throw a cam in before reinstalling the engine in the car. We were talking about how the rpm range would be with an auto. He is keeping the stock stall and 3.23 gear, 4L60E. Neither of us have experience with the 4l60e or racing an automatic.

1.) Now with the a4 are the gears selectable? For instance if you put it in Overdrive from the get go will you stay in Overdrive until you manually shift? Is it the same for the other gears? Will your rpm's be higher if you start out in overdrive or if you you start out in drive? (I would guess drive since it is 1:1 but someone was telling me that placing the shifter in the overdrive position will not have any effect other than not allowing the car to shift out of that gear-no rpm increase/change?)

2.) What would be the the best gear for racing from a dig? From a roll?

3.) Now I know with a manual overrev is beneficial is it in an auto with stock stall?

4.) Does the pcm shift gears based on rpm or speed?(I would guess speed)

5.) How would reprogramming the shift points in the computer affect driveability? I would assume you would not want the car to shift until ~5700 daily driving it in 2nd gear with the stock stall but if the shifts are based on speed...?

I guess the above might be different if you could manually shift and hold the car in a certain gear not allowing it to shift until you reached a certain rpm? Isn't that bad for the trans? Or is this not the way it works?

6.) Does the computer shift differently in closed loop and open loop?

7.)Iss there a rev limiter on an a4 (what is it set at)? How does that work when you top out in 4th?

8.) Does anyone know the stock shift points for the 4l60e?

So essentially, as far as the cam would go you could not effectively rev the car to ~5700 (without manually shifting) before the car would shift gears without a higher stall? correct? so a smaller cam with a narrower powerband would better benefit a stock stalled car (try not to look at it from a lowend loss perspective but rather a better utilization of the useable powerband.)I would guess 4th would be the only gear you could reach high rpm's like 5700 plus (stock stall 3.23 gear)?

Now my guess is that the if the gear can be manually held and the rpm's increased that way before the car shifts. But not manually shifting you would not benefit from the extra rpms except when in 4th?



Again sorry for my ignorance but I only know my m6 lol. so much simpiler to understand.

 

Wow where do I start... Lets just say you have the totally wrong outlook at what a transmission is and how it works, sorry no offense intended...
Yes, the gears are selectable, but not similar to your example. The tranny has 4 gears, 3rd gear being 1:1, if you put the selector in D or OD it will shift on it's own starting from 1st going all the way up, D will go up through 3rd gear and hold 3rd a little longer but will eventually shift (I will get into why later). If you put the selector into 2nd depending on modifications to the trans you may or may not start in 2nd gear, but when it gets to second it will hold there then eventually shift as well. these eventual shifts are because inside the computer there are different tables for shifting normally and shifting manually, and if it held in gear it gets to the max of that table then shifts itself, thinking the driver must have accidentally forgot to shift... You have to modify the trans quite a bit to have it work as manual shift only, but they are a pain to always have to go 1-2-3-4-3-2-1 when starting and stoping, but there are people out there that do it...

Are we still talking transmission here? If so then that depends on a lot of factors, are you one of those guys that like to sound like you have a manual and like to hold it out to try to intimidate the opponent (that doesn't work by the way, I've had many years of street racing when I was younger and tried everything) if so then keep it in 1st and make a lot of noise. If you want to shift manually then it depends on the roll speed. Use the calulator in my sig to figure out what RPM you will be at in each gear at your roll speed and pick the one that puts you in your powerband properly. But most of the time you could just let the tranny do the shifting for you, the advantage of the automatic ...

What are you talking about? Please explain yourself here, I can't see what you asking or even talking about. What do you mean by manual overrev, please tell me you not talking about reving it up in neutral then dropping it in gear if so that tranny won't last long...

Both, it references rpm and speed and when both conditions are met for a preset (in the computer) throttle position then the shift is made...

Read my answer above again, there will be no negitive effect on drivability if you change the shiftpoints correctly, meaning don't go and tell the computer that at 5% throttle you want it to rev to 5700 RPM's... tell it at 100% throttle you want it to go to 5700 rpms and in the table holding the mph again check out the link in my sig to figure out what the mph is at 5700 rpms and put that there at 100% throttle. As for the second question here, I can't figure out what you asking again...

That's not too bad for the trans, if it's built right, and also read above on how it all works...

yes and no, there are different things that effect it like temp, and line pressure and shift points can change due to temp via the computer...

There is no rev limiter in the trans, the trans is just a way to multiple the output of the motor, ie different gears, the motor is the item that revs and it is the only thing with a rev limiter, understand? When you top out in 4th gear you are actually taking the motor to the highest rpm available through the computer, which will be tough to do since my 2.73 won't get near the factory rev limiter till about 228 mph in 4th and your 3.23's will be about 192 mph, and these cars don't make the power to go that fast, the fastest I have had mine was around 145ish on the street, but I need to run it to 160 on the dyno to fully read 2rd gear, again our 1:1...

I could figure them out but, I would think they would be at about 5200 RPM's, meaning at 100% throttle you are probably shifting at about 40 mph in 1st gear to 2nd, 76 mph from 2nd to 3rd, and 123 from 3rd to 4th.

I would change the shift tables in the tranny to have it shift properly, also when manually shifting it won't hold to 5700 rpms, on a stock program probably about 5350 max in manual mode. Also you may want to move your stock rev limiter up too if your moving shift points, since it, if I remember correctly, sits right around 5700 rpm's...

Higher stalls change the front half of the rpm range not the back, for a simple example, mine will stall up to 3500 rpm's if I jump on full throttle at a stop and will kinda stay there till the wheel speed gets the car up to that point where it should be vs that rpm (puting me directly in my powerband) then I continure to accelerate through the rpms while maintaining a similar wheel speed to someone with a stock converter. This was a simple explaination there is obviously more to it, but it is to get you up into a powerband instead of bogging down first and doesn't really effect the shift point too much...

If you are not planning on changing your stall then I would say stick to stock for the cam, there is no reason to hold any cam back. I still have a fully stock motor and run a higher stall, because the stock stall will seriosly hold these cars back by not letting you into you powerband quickly enough. In other words, match your components to make the most of what you have, if you put in a cam with a powerband of 3000 - 6500 and keep a stock stall then it won't run much faster if any then it does now, and there is a lot that goes into choosing a stall too. I would say narrowing the powerband would not help with a stock stall, it could be very fat, you just have to make sure it starts low and peaks kinda low too, but then when you do stall the car it will still be mismatched...

I hope this helps...

 

The stock shift point is around 5800-6000. Shifting from first to second in my car is around 45-50 mph, and second to third is around 90 mph. It will be a little lower for 3.23, but not too significantly.

I have held it in manual first until it hits the rev limiter. Never have I had it shift on its own when holding it in a gear. Stock rev limiter is at 6200.

Why are you worried about the RPM range with an automatic? It would be the same with a manual, just a little more power. An RPM power range just tells you where the power is and where to shift, and among other things. The transmission will behave the same as it did before the cam.

OD is just like any other car with OD, you cannot select gears while it is in OD, you actually have to pull the shifter to the gear you want.

Lastly, you might want a bigger stall depending on the size of the cam.

 

Firstly THANKS 1slowformula for taking the time to type all that! I know it was a long post but I genuinely appreciate you taking time to answer all of my questions. The fog is clearing..

I do have one additional question:
So basically raising the pcm's rev limiter would be pointless unless manually shifting? Or, I won't be able to reach 5700+ rpms without manually shifting even when changing the wot shift points (assuming stock stall and 3.23)?

The thing about the overrev was in a manual you rev past peak so when the next shift occurs you are higher in the rpm's than if you shifted earlier when changing gears. Not sure if that is even possible or beneficial in an auto?

Also the cam is an off idle to ~5900 with better than stock lowend (huge torque)

 

put another way: are high rpm's a waste of time on a stock stall/gear car even if the pcm is modified (reason being not being able to reach high rpm's w/o higher gears/stall)? What is the max rpm hold when not manually shifting gears?

 

Who said you will not be able to reach higher RPM's without gears or stall? I think you have made an association between the way the tranny works and the RPM's the engine produces and that association is wrong.

Simplified:
A motor will rev from idle to wherever the revlimiter is set in any gear even park and neutral. The transmission uses the power the engine produces when it is revved to push the car forward, there are different gears that change the speed the car will go at a given rpm, but either way it will rev the same no matter the gear. So you can still use higher RPM's without issue if you set the computer up to shift higher and raise the rev limiter so you don't hit it when you raise the shift points.

As for my comments in the earlier post about the stall was just to point out the need to optimize everything to work well together, not to say a cam with a stock stall won't work at all, it will just be inefficient. As for gearing that will determine acceleration not if you can use higher rpms, so if you want to accelerate faster you need lower gears (numerically higher), and if you want higher top end you will want the reverse, again this has to do with optimizing the setup and nothing to do with not allowing the motor to rev where it needs to for the cam you are looking to install...

I hope this clears it up a little more for you...