Curious as to what shift RPM's you all are seeing on the 1-2 and 2-3 upshift in M mode or S mode...seems 6k is all I get. Is that correct ? It's still pulling HARD at 6k and it seems like I could wring a bit more out of it if there was a way to actually shift this thing manually.

 

My 06 gets close to 7k before it shifts when I'm on it. Not sure if it's supposed to do that, but the SA said it's alright.

 

Peak power occurs around 5,400RPM so shifting after that is a waste. You are just revving the car up and slowing yourself down. When I am running against other cars, I am in M mode and I shift at 5,500RPM.

Now, saying all that... In S Mode my 03 automatically upshifts at 6,400RPM.. You can see it in the video I posted doing 63 to 117mph.

 

Thanks guys.....is the rev limiter on this car unmistakeable when it comes in like its taking out random cylinders or does the car just lay down ?

 

its not a harsh popping/backfiring limiter, rather a smooth rolling limiter..

gee i didnt realise that anything past 5500rpm is a waste of time! So when at the track, everyones PB's are achieved by NOT revving to redline?

 

It's a fine line really.. Shifting sooner drops your RPM lower than shifting later does.

I may be in the minority on this one, but, most people will argue that you should let the car shift at 6,400RPM. My position on this is that the car makes a pretty consistent amount of torque right from 2,600RPM to 5,000RPM so the gear changes will always be inside our torque band.

Also, at 6,500RPM you've got at least 100hp - 150hp LESS than you do at 5,500RPM. The amount of time you waste revving the motor that extra 1,000RPM you are doing it with alot less hp.

Try it in your car... Go into M mode and shift the car at 5,500RPM and see how it feels compared to S mode at 6,400RPM. Pay close attention after the RPMs climb past 5,500RPM and you should be able to feel that the power has dropped off considerably.

These cars are not typically of what is out there.. Everyone has it imprinted in their brain that redline is where max hp occurs so naturally everyone heads for redline everytime they drag the car.. Unfortunately that is not the case for us.

I guarantee that the time you waste in S mode letting it upshift itself is alot more than you manually shifting the car in M mode.

I always drive the car in M mode when I am "competing".

 

True Vic...redline usually indicates the highest RPM the engine SHOULD safely spin...not where the most poser is....I just thought it would shift itself higher than 6k....I'll try 5.5k in M tomorrow and see how it feels.

 

Hmm...Very intresting points...

So you say when I race other cars I should upshift at 5500 and I will be faster ???

When I raced M6 over weekends I noticed at higher speed he would catchup with ME ones the gears where changing from 3-4 and it seems that the cart would hit the limiter and make some kind of pause, while M6 would catch up and pass...this happans around 120...

I need to practice more...teach ME

Do you also run M mode in 1/4 ???

 

I haven't been to a formal 1/4mile track with my E55 yet. But any informal street encounters I am always in M mode. I drive 99% of the time in M mode because I find I have more control that way.. In S mode I dont like the shifting patterns the car has .... It tends to put you in a very high gear (4th I think) when you are just putting along at slow speeds.. I dont like that so I shift myself.

Get your friends together again and try running in M mode this time. Just make sure you are in the right gear when you are doing roll-on races otherwise you will lose badly! As long as you have the right gear selected, just keep an eye on the tach and shift right when you hit 5,500RPM.. That should keep you will into the powerband and should put you ahead.. Try it on your car and tell me what you feel.

Also, another benefit is that you won't heat soak the motor as badly because you are not spinning it all the way up to 6,400RPM, so there is a minor cooling benefit also.

 

Well as we know the newer models wont upshift in manual and I have hit the limiter too many times in first to use manual on an outright drag...

Also I find the shift button is not very quick in first - I hit the button and ntg happens sometimes and I hit the limiter - very annoying. Maybe I have teh pedal into the kickdopwn switch and it overrides or something not sure have not really had a chance to play ..

So I use sport mode and select gears manually within sport mode. I cannot hit limiter. I only use the buttons to down shift and let the 'box upshift on its own - I figure it has to klnow the optimuim upshift right ?

Vrus something to keep in mind with your logic re lower HP at higher rpm - This is only true if you are making more power at the lower rpm level when you switch to the next gear. There is a formula to work out exactly what the optimum upshift point is (i.e. where the new power level > current power level) - and I doubt it is going to be at the engine power peak of 5400. I'll see if I can figure it out ... but it should be easily read off the power curve.

 

I'm curious, how do you get the car to short shift in M mode? If I have the car floored, and I hit the button at 5K is still upshifts just below the limiter? When you shift at 5500 what RPM does the shift actually occur? It is far from quick......

 

From 1st to 2nd if I try and shift at 5500 I might just get it done before I hit the limiter... its vvvvvery slow.

I reckon according to my calcs so far ...

Optimum upshifts are

1-2nd 6450 (ie. just before limiter) and thats assuming we have only ~425NM of torque at 6500 rpm. So its best for car to do this automatically in my opinion.
2nd-3rd 6450 - same deal
3rd-4th 6400 slightly earlier
4th-5th 6200.

This means we hit
2nd gear at 3900 (yeah that low)
3rd gear at 4150
4th gear at 4600
5th gear at 5150

Problem is our gearing is so long its drops the car much lower down on the power curve ... so you need to stay in gear as long as you can - even past peak power.

 

I've heard alot of guys complain about shift speed.. My 03 shifts right away.. I hit the button at 5,500RPM and it shifts at 5,500RPM.. If I am foot-to-the-floor I hit the button as soon as I see the needle blink past 5,000RPM and it shift around the 5,500RPM mark.

The technique seems to work good for me. I will try it again on the highway and pay closer attention to the RPM drop in each gear.

 

Oh yeah.. Forgot to mention.. I am working on something to resolve this.

How would you like 2.92 gears in that bad boy?

 

Me likey! Any speedo issues?

I will do some back-to-back shiftpoint testing on the 27th of August at the dragstrip. Results to follow.

 

Steve has come the closest to getting this right. The best 1/4-mile times will come from maximizing the area under the HP curve when shifting gears. The actual shift point strategies will vary from car-to-car depending on the shape of the HP curve. For the E55, the HP peak is at 6100 RPM, with a fairly gradual rolloff on either side. Also, since lower gears accelerate faster than higher gears, it's best to stay in the lower gear as long as possible. This is valid as long as the HP level in the lower gear is higher than the HP level in the higher gear if you shifted.

For your cars, 6400-6500 RPM shift points seem about right.

Victor, I looked at your dyno plot - your car is peaking about 500-600 RPM too soon. Others have posted their plots and show peaks in the 6000-6100 RPM range. Your A/F ratio looks OK, so it's probably heat related or an airflow problem - either a restriction or lost boost.

 

someone with one of the new gtec units could figure this out quickly.... I used to measure shift points vs times in my Viper.... only time I picked up some time short shifting a little would be in the 3rd to 4th gear change....

I don't think shifting at 5,500 RPM's in the E55 is going to make the car quicker.... my car runs up to 6200-6300 before shifting....

 

It's quite possible.. That could of been due to the belt slip issue which I didnt know I had or the cooling system not running 100%..

I am trying to get my tune fixed.. As soon as that happens I can get another dyno done to see if all is well.

 

Spot on. The only other main factor is tranny gearing.

 

Just tried 5500...not too good...this thing is pulling like a freight train at 6k...still can't get above that...

 

Please expound on that.

 

Really?? I was just messing around on the highway again on the way home. In M mode, I put my foot to the floor and as soon as the revs hit 5,500 I shift.. pulls hard for my car..

Maybe Grumpy is right and its because my tune is off.. My car does make peak power at 5,400RPM right now so maybe that's why it seems strange to me when rev it up higher....

Hmm.. Has anyone else tried this?

 

Maybe it's me but I'm used to feeling the car start to lay down and I know I am out of the powerband and thats too late to shift.. at 6k it sure as hell doesn't feel like its done. Its still has you pinned in the seat. Not very scientific but then I don't look at the tach when I shift my other 4 speed cars. I know you want to keep it at the peak tq vs hp but it just feels like there is more there .