Does this tune make faster response time in manual mode (from the driver hits the paddle to MCT shifts)? With original software and full throttle in second gear, it's hard to get third gear without rpm limit kicks in...

 

stock crank tq

1st gear TQ limit: 650nm/ 480 FT LBS
2nd gear TQ limit: 800nm/ 590FT LBS
3-4-5-6-7 gear TQ limit: 900nm/ 660FT LBS


With the EuroCharged stage 1 TCU Tune what are the new torque levels set to?

 

These arent engine TQ numbers from the tune, these are the limits from factory set in the trans.
With the TCU flash tune, you can set these limits up to whatever you would like, or completely removed.

 

with the stage one tune what are they raised to from the above stock limitations?

 

70 lb-ft for each gear for 1, 2, 3

approx

 

thanks!

so talking very literally, and I’m ver ignorant here just trying to understand or have some one help me understand

let’s say now I have the tcu tune and my new tq limitations at the crank are now

1st gear TQ limit: 550FT LBS
2nd gear TQ limit: 660FT LBS
3-4-5-6-7 gear TQ limit: 730FT LBS

at the same time I have an ecu tune lets got with the eurocharged stage 2. My cars crank hp/tq is now 697/hp 761/tq (from their website)

logically it wouldn’t make sense to me to not try and get anymore power out of the car because all the tq would be restricted creating a lot of diminishing returns. Is this true?

or is the hp not restricted and you can really improve up top times like 60-130 just no so much on 0-100?

thanks!

(I’m stage one eurocharged ecu and tcu tune and love it)

 

you are correct
and anything 4th gear and beyond is all on your ecu tune like a 60-130 pull

 

Hi all. This seems an appropriate place to ask question that I can't get my head around. Can anybody explain why my thinking is, (obviously not), correct.

So, it seems that the software limits torque in the lower gears to protect the transmission. My head tells me that this doesn't make sense - here is why.

If you have something that is working against a resistance then that 'something' is under more stress. So if you were to have a car running on a set of rollers, (NOT a dyno), for a given gear at a given engine speed it will require 'x' energy to spin those rollers. If you then put it on a dyno where the rollers are effectively braked it requires a lot more x to reach and maintain that speed.
Similarly if the car was on a big treadmill running at 100mph, when the car is flat it would again burn 'x' energy to run at 'y' speed. If you were to then raise the incline it would take more energy to run at that given speed.

It seems to me that the transmission would be under less stress at no load, (it's not no load of course but low load), conditions.

In the lower gears, you have less mass to shift and less air resistance to worry about so surely the tx must be under less load/stress? At higher speeds the same is not true.
So is it really only limited to ensure that you don't keep bouncing off the rev limiter or spin into the nearest ditch or is it to do with something else?

Appreciate your thoughts.

 

Your resistance is the 4600lb weight and the awd system that'll ensure maximal transfer of torque to the road ... and in this case the first item to bite it is often the output shaft

but I may not be understanding you correctly

 

That doesn't help.

Think of yourself on a Mountain bike.
In first gear, you may be able to get the rear wheel to break traction. In top gear you cannot as you don't have the power even though you are throwing at it all that you have. Uphill the effect is even worse.
I wouldn't mind betting that the chain is under more tension when you are in top and giving it all you have than when you are in first on a slight decline?

 

Here's one way to look at it.

Which is going to put more torsional force on the output shaft - 4600lb mass accelerated from 0-60 in 3 seconds, or same mass accelerated 60-120 in 7 seconds.

I would argue (although could be wrong) that the output shaft is under significantly more stress in lower gears since it's trying to do more work in a shorter period of time, hence the torquemeter value being used to retard throttle. Output shaft speed is a fixed ratio to car speed since there is no gearing downstream of it.

Upstream on the other hand, the transmission is probably under more stress at higher speeds. But those gear teeth are sufficiently strong to resist the shear forces involved.

Anecdotally, in one of my prior vehicles (4g63 DSM) the first thing to break loose is your clutch. Once you upgrade that then your half shafts break in first gear. Once you upgrade those then your 3/4 gears start getting chewed up. Every vehicle has its sequence of what breaks and it appears on the E63 212 platform it's the output shaft.

 

Will have to have a think about that one as I'm not sure.
Not for a second arguing that parts might break but just that it seems to be doing less work at lower speeds. As for doing more work in a shorter period, I can see that but at the same time I have to ask myself if in fact it's doing less work but more quickly if you get my meaning.
(0-60 x 4600 x 1 Air resistance)/3 = (60-120 x 4600 x 10 Air resistance)/7.
That's not even close to being a real formula of course but it might help to show how my mind views that it takes more energy to accelerate to and maintain higher speeds

I'm going to have to check some physics texts I think but thankyou.

 

Don't you think the gearing in lower gears is designed to produce more accelerating force than at higher speeds (compared to final drive ratio)?

Doesn't this force get conferred to the output shaft?

 

I will have a crack at giving my understanding, the last part you say that in lower gears you have less mass to shift? That’s not the case the car weighs the same all the time, you can more or less forget about air resistance as well as far as this is concerned.

The torque limit is a software limit to protect the transmission (in this case it sounds like the output shaft is the first thing to go) the fact it’s a software limit doesn’t mean that the torque is straining at the gearbox trying to break through it means that the TCU & ECU systems are capping the peak engine torque to protect the driveline.

My understanding is that before the advent of TCU tuning the ECU tune would under report the torque figures that it sent to the TCU to trick the system into letting more torque through, with the TCU tune being available now the engine can send the correct figures and the TCU and ECU together can control to new raised limits set (or even removed) in the TCU tune. There’s probably less risk of breaking output shafts on a RWD car because the tyres will slip, you guys with the AWD cars can grip and rip and then the first weak point in the driveline is the output shaft as you won’t get wheels pin like us UK guys get.

I think the analogy with the bike doesn’t really work to well because the ECU and TCU is doing so much more of a complicated job than just pedalling as hard as you can. The ECU and TCU pretty much never let the car go as hard as it can as it wouldn’t be good for anything.

Hope that makes sense haha

 

From an amazing mechanical engineer:

"OP needs to look at the bicycle analogy and view the power transmission system as an analogue of a car transmission where the rear driven axle is like the output shaft. Bicycle power transmission is the combined front sprocket, chain, and rear sprocket size. Obviously in 1st gear you would put the most stress on the rear axle. Hence able to spin rear wheel in the dirt with some ease. With gear ratios involved, the stress points change in the sequence of the system. At higher gears and faster speeds there is more torque on the motor crank. At launch and lower speeds you take more advantage of mechanical advantage in gear ratios toward the crank, but have higher torque at output shaft.
Make any sense? Or am I mumbling again? 😂"

 

People are saying the output shaft is the current weak link. Is there any work being done to address that (maybe by the guy/company that made the "E63R" super build)? With companies like Blackboost putting out parts that people were traditionally concerned with (stronger transmission parts) I feel like there is opportunity to stretch the platform further and see how far it can go.

 

yes, cryo.... it'll only push the weak link to something else perhaps more expensive to repair ... So trans needs to be built up ....

 

@5soko check your PM's!

 

Only just noticed this now, sorry.
So I think I'm getting it now. Remember torque is a reaction and there is less in a lower gear which is why you can spin the gears in 1st and 2nd, (maybe 3rd), but not the higher gears as you don't have the power to do so.
The tx will multiply the torque which is fine but again, you can fight against an equal and opposite reaction? This is why a dyno has resistance and does't just allow the wheels to spin in free air?

The torque multiplication is the key here I think though.