This is for all you real gear heads out there.

Allmotor, typeR, scalbert, Jens H, etc.

Have any of you guys looked in to the program logic that controls the tranny shift characteristics?

I'm trying to find out if it is possible and how hard it would be to retain the shifting profile the tranny has during warm up.

I'm sure most of us have noticed that during warm up the tranny has a more agressive shift profile. The shifts are noticably firmer and quicker during the first several minute of driving.

Then after warm up, it gets softer, and just isn't as fun. :shakehd:

Anyway, as most American Muscle car owners know, adding a shift kit to your tranny not only made it more fun to drive, but helped drop up to a couple of 10ths off of your times.

So, while we don't have a shift kit option, a good one anyway (in reference to level10), is there something that can be done to the ECU to keep all or most of this warm up program in effect after warm up?

I believe that if we could find a way to do this, it will result in some noticeable improvements in our NET WHP. I would guess in the range of 7-15WHP.

Thoughts ?

Ruf

 

is it really the tranny comp making the first few shifts harder/faster? or is it just that the tranny fluid isn't warmed up? But then again, if it'snot warmed up, you would think the shifting would be more lethargic. There is only one tuner I know that makes a chip for the tranny. That is Garrett (GIAC). They don't tune Acuras tho. Not sure if tuners are looking to mess with Acura tranny's right now :o

 

What Ray said, it is the tranny fuild when cold the CLS shifts hard... once warmed up the it shifts smooth as any luxo car should.. This is why the tranny is warmed cooled via the Coolant fluid exchange.

The firmness does not make the tranny shit FASTER.. it's 0.8s in SS mode and 1sec in D5 mode!!!

Nashua.

 

so a nice trans cooler and some redline hi temp and you'll be closer to what youre after and for only a 100$

 

I remember the days of the shift kits

I had a 1971 Plymouth Duster and had a Turbo Action shift kit installed. A big difference, much crisper more solid up-shifts...it would even squeal the tires when up-shifting on hard acceleration like passing gear!

Sold the car at 125,000 miles in good shape (which was good for American cars back then)...

 

I appreciate the responses so far, but I'm not buying the colder vs warmer fluid being the factor here.

I do recall somewhere that while the car is warming up, the ECU has a warm up profile that manages the way the tranny shifts.

For example, it also manages the cold start valve and fuel mixture.

I know someone will have the answer for us . . . .


Ruf

 

The car does shift later/rev higher when cold, but that's only to help it warm up easier - the way in which it's shifted does not change.

 

Juker008

 

Humm, maybe the colder (thicker) fluid does make it feel different.

I'll wait and see of anyone comes up with something. I know our trannys may be a weak link, but it's such a shame that we lose so much HP through it.

Ruf

 

Maybe the quick hard shifting helps accelerate the heating of the tranny fluid & it then shifts softer when the fluid is at optimum operating temperature. If this is the case, programing the ECU to stay in "warm up" mode all the time might cause the tranny to overheat. I am no expert, so maybe Scalbert, allmotor2000 or some other more experienced mechanic can comment.

 

Okay, I think I've eliminated the shifts harder when cold because it revs higher part as a factor.

Since the terminology implies that its reving the engine out higher before shifting, then there shouldn't be an advantage when I take it to redline. I mean how much higher could it run it out than that?

So, if the only other possibility is the thicker (cold) fluid increases the pressure within the torque converter.

So, one way to test this is to increase the thickness with an additive and see if the tranny still shifts as hard. If it does, then we know that is the likely factor.

NOTE: One will of course want to change the fluid until we know what the impact of "the" additive is.

So, if I can find an additive I feel comfortable with, I'm very likely to test it out . . . and of course I'll report any findings.

Ruf

 

Use sand.

Seriously, you answered your own question. It's the thickness of the tranny fluid when it is cold that transfers power better. Also, if the tranny is cold the motor is most likey cold as well...more HP\Torque right there. Although overheating would be more dangerous to tranny fluid, I am sure the operating significantly under optimum temp could be harmful as well.

Also, we have a transmission expert on the Legend board who highly recommends AGAINST running anything other than Honda ATF. This is not a dealer, he is an independant. Just as the motor has certain tolerences for clearence, the tranny has certain tolerence for the viscosity of the ATF. Also, the different blends of detergents make a difference on the life of the bands, clutch packs, etc.