I hated my MN6 because I love to shift continually on curvy roads and it was so notchy I hated it. Was considering a Boxster just to make shifting fun. This weekend took it out and figured I'd give it one last try and since the Boxster would have to always be over 3K RPMs to even run I decided to give it a try on my C6. Set the HUD to track mode and never let the line fall off the flat part of the RPM curve which means engine was always between 3 - 7K. I was amazed at how the transmission turned smooth as silk, no notchy feel and super fast shifts. If you hate the notchy shifts, give it a try. Saved me bout $25K.

 

so what did you do, just beat the **** out of it?

 

There is no substitute for HP and torque. If you get a Porshe get a 911 or don't waste your money. The C6 will even give the 911 a run for it's money. Kind of funny that if you want a foreign car to compete with a c6 you need to spend an additional $30K or more. The c6 made car and drivers magazine 10 best list for a reason, nuff said.

 

One additional advantage is you don't need CAGS eliminator. $20 saving.

 

You know, its funny that you mention this. My car finally got passed its break in period, and I got to do a nice little row thru the gears at higher RPM's. After driving timid during breakin and noticing the notchiness, I found that under brisk acceleration and rowing, I had no notchiness at all.

 

In all cars I've ever owned (even bikes), seems that the tranny was always smoother and easier to shift when run hard and at higher rpms. I usually baby my cars most of the time... but the few times I have beaten on them hard were the times they ran the best.. especially the trannies. Probably has to do with higher oil temperature in the tranny... the hotter, the thinner... everything moves that much more freely.

 

I don't think that's beating the transmission; it's the way the box was designed. Maybe an engineer can weigh in here, but I learned to drive on an unsynchronized 4-speed in a 105 hp import. You kept the rpm high all the way up and down through the gates (double clutching). There were no transmission problems.

 

On a C6 specifically, will double-clutching help at all? Will doing so improve shift quality, and/or be beneficial to the tranny? I realize that on other older trannies double-clutching is helpful and maybe even necessary, but on the C6...? I never even attempted double-clutching my C6 yet, haven't had the "need" to do so. Just curious.

 

it takes a short time to help break in the trans.

no double clutching will not help.

replace the trans fluid with synthtic trans fluid. I use Mobil 1 ATF.

I also took out my shifter and replaced the bushings and packet full of grease. Now after several thousand shifts I can shift with one finger( well almost)

 

The syncronizers will last longer, but they may last as long as the car anyway.

It forces you to pay a lot more attention to your shifting so will help your driving skills and you will become a smoother shifter.

 

Thanks. How do you guys normally shift your C6's though? Do you actually double-clutch on a normal basis? If not, when you do shift, say at low load when just buzzing around town, exactly what technique do you use, and how smooth are your shifts?

When I am accelerating with low load, say from 1st to 2nd, I first step on the clutch while letting off the gas, then with the clutch fully depressed, make the shift, and then let out the clutch kinda quick while simultaneously bringing the revs up slightly in hopes of matching engine rpm to drivetrain speed, then once the clutch is fully engaged, begin accelerating again.

75% of the time I can seem to do this so that absolutely no shock or sound of any type can be sensed... an almost undetectible shift. Other times, I hear a very slight "clunk" but no shock. Other times, I hear no sound but if the rpms are not matched just right, I will feel a slight "buck". With the drive by wire, it seems trickier to get the rpms matched just right than with my other older cars.

Is there a better approach? Comments? Though I've driven manual trannies for years, I was never actually officially educated in "how" to drive them. My goal is to make dead smooth shifts and put the least amount of wear and tear on the tranny / clutch possible.

Thanks.

 

I'd like to hear more on this too

 

Today's manuals are generally precise and tough, including the T56 Tremec. But there are some fundamentals to manage. I'm not an engineer, but here's the way it has been explained to me.

When the tranny is engaged, the crankshaft and driveshaft turn at different rates depending on the gear ratio. When you change gears, the ratio changes and, when you let out the clutch, there is a split second when the turning rates are out of synch. It can translate into a 'clunk.' So can a faulty u-joint or a worn differential, by the way.

Upshifting is easy because there is no inertia to overcome. But downshifting requires overcoming the driveshaft's rotation. In earlier generations, we used to 'blip' the engine rpm just as we shifted down to bring the crankshaft and driveshaft into closer synch. It can take some of the pressure off the gearbox which now sits in the back of the car.

In my '96 C4, I still use this blip-and-shift pattern when downshifting in corners, or even climbing suddenly steep inclines. But I haven't experienced this when driving the C6, maybe because I haven't driven it hard yet. I have noticed the clutch spring issue mentioned in other threads.

Some of the technical guys here can probably explain it better.

 

You did a pretty good job.

A third element is the rotating clutch disk/trans input shaft which is rotating separately of the engine and tranmission when the clutch is depressed.

When you double clutch, you let the clutch pedal up momentarily in neutral and blip the throttle to spin the disk up to the right speed so the trans input shaft matches the speed of the next gear it is going to engage. You don't need to do that on upshifts because the disk is naturally slowing down so you can just time it right.

There is no need to doubleclutch an MN6 transmision, but it's a nice skill to develop and does help syncro life a bit.

 

On upshifts ans downshifts, I blip the throttle ( always have) and it seems to help with making the transition between gears smoother. It takes a little practice to get the right blip and clutch engagement, but it works. Of course, if you really want to get really serious about downshifting you need to do the heel and toe method road racers have used for years.

 

This is exactly what I try to do. On any other car I can master it in a matter of an hour so there is no clunk or serge and everything matches up perfect. The C6 is harder and I am at about 75% also and the rest of the time I get a clunk because the speeds are not matched. IMO what makes it harder with the C6 is a combination of the added mass of the driveline hooked to the input shaft of the transmission, the long throw throttle and the long throw clutch combined with the low seating position making it hard to reference your heel to a point on the floor. That all seems to get better if you drive it a little harder and keep the revs up. If I go to track mode for the HUD and keep up on the top of the bar everything is grand. Not saying I do WOT all the time but just ease it up to higher RPMs. I used to shift at about 3K and now mid 4's really makes it shift nice. Which I hadn't happened to get a car with huge vibration in the shifter, but still makes it shift nice.

 

I started trying to learn heel and toe shifting and found that blipping the throttle on downshifts really smooths them out - not nearly as notchy. I'm now doing that most of the time.

 

Blipping the Throttle is always a good idea.

But, I just changed my fluid to Royal Purple Synchromax, and it made an amazing difference.

http://www.royalpurple.com/prodsa/scmax.html

 

I'm a bit confused about the term "blipping". To me, "blipping" means to quickly jab the accelerator pedal to bring the rpms up very briefly. I think if I were to merely "jab" the pedal quick and then do a downshift, I would not be able to get the rpms matched well and would result in an abrupt shift.

When I downshift, I DO press on the accelerator pedal gently to bring the rpms up to match the drivetrain speed, but I never "jab" it... it's more of a gentle press. Or perhaps "blip" does not mean "jab"...?

In a few cases, when I needed to upshift and felt less confident about doing a fast shift (especially when I was not yet familiar with the car), I'd actually estimate in my head the amount of rpms I'd need from the engine to make a smooth shift, I'd then press the clutch down, shift, and then slowly open the throttle until I saw the desired reading on the tach, held it there, and then let out the clutch... and this actually worked well since I was good at estimating the needed rpms. Of course shifting like this is slow and impractical, but it helps exemplify my point about matching the rpms well which would seem to be hard to do by just quickly jabbing the pedal.

Heel and toe... wow, that seems really tough to master. I think it would be hard enough to get the brake pedal pressure just right to begin with in order to slow the car down as fast as possible without locking the brakes, let alone have to reach over and "blip" the throttle with the same foot at the same.

Ironically, now driving the Vette, even just around town, I have more and more "need" to heel and toe since I'm driving this car in a more spirited fashion than I have with other cars in the past. But I'm still too chicken to try it. I usually just wind up braking into the turn, making the turn, and then just downshifting before exiting the turn after no more braking is required. Yes, this makes for an overall slow corner, but will have to do for now until I gain more confidence.

 

A blip is a quick tap on the throttle. With practice you can get good at it. A good driver can heel toe double clutch downshift faster than the average drive can do it using the syncros to match speeds.

Practice heel toe in a nice saefe place in a straight line, work on one skill at a time so you can focus on it.

Your cornering technique is almost exactly wrong, you should break that habit before it gets fully engrained.

For now, do all you downshifting and braking before you get into the corner, it's good idea to do it that way later too. Go into the corner in the gear you want to be in when you come out of the corner and accelerate a bit through the corner.

If you need to brake in a corner and can do it it means too things.

1. You went into the corner too fast.

2. If you have enough traction to brake, you aren't going as fast as you can.


Trail braking is another topic, usually the term is used as an excuse to explain why a driver didn't time his braking properly

Rather than type a description of trail braking, I found this with the help of Mr Google.

Trail Braking

Looks like an interesting website.

Trail braking is not a good place to start learning. Your are better off learning one basic performance driving skill at a time until it becomes second nature.