serickson

Here is how you downshift in a cup car. Check it out. http://www.youtube.com/watch?v=Q3hrpkHoyrM

claykos

I used to downshift without the clutch all the time in my old race car which had a Jerico dog ring box. Simply blip the throttle as the box is sliding through neutral between gears.

mooty

1. can we do it with cup car box? or even 996 cup?
2. so move the stick firmly, when it's in neutral, blip, then slide in gear? but before it's in neutral, wouldn't it crunch? or maybe with dog ring, it wont?...

i guess i should just stick with the 3rd pedal...

Bryan Watts

You're missing that there is a brief pause when the car is in neither gear during which you can blip the throttle. Did this all the time in my old Formula Mazda. Once you get good at it in those cars, it's easier to shift without the clutch, up and down. On upshift, just a slight breathe of the throttle, and the gearbox would almost pull itself into the next gear once you started moving the lever.

Actually, we saw less wear on the dogs when downshifting without the clutch in Formula Mazdas. Those boxes spin up and down so quickly, that it was near impossible to get the timing right when using the clutch...it just took too long to complete the shift. The timing was far more natural and easy when forgetting the clutch all together and using a quick blip while the transmission was between gears.

If it's a dog box, you should be able to. I'd be happy to try it in someone else's car as long as I'm not liable for the rebuild that may ensue.

C.J. Ichiban

mooty come drive formula cars with me sometime and you'll be left foot braking in everything!

in any sequential gearbox, all you have to do is come off the gas abruptly enough and you can change gears without using the clutch- in some cars (like a cup car) you flat shift, in others you only have to go from full throttle to a 50% throttle, while in others you have to come all the way off the gas otherwise it's crunchy.

you have to rev-match the downshifts really well but just like anything else with a little or a lot of practice...

the formula mazdas that bryan (lots of experience) and I have driven(briefly for me) don't even have sequentials- they're H-patterns and you still don't use the clutch at all. you just have to be careful not to put "side-load" on the shifter as the throws are literally ~1.5 inches from gear to gear. the good thing is since you left foot brake in these cars- all your right foot has to do during braking is learn how to blip correctly!

a 996 cup car has a relatively long throw h-pattern with synchros so there isn't a benefit other than becoming friends with your pit crew/transmission rebuilder.

333pg333

I thought it was just a '74 E Sportmatic. lol

See this shifting all the time with Sequential trannys. Nothing new. Looks like too much fun though.


Here's some good footwork on a traditional non sequential gearbox. Still no clutch and almost all LFB.

http://www.youtube.com/watch?v=azpqTZ6WeJk&NR=1

C.J. Ichiban

patrick thank you for posting that! perfect example.

333pg333

As ever CJ, I'm merely here to serve.

I actually think the Aussie V8s are a great series to watch. Some really good camera angles and new ideas for coverage. That clip is back from '06 I think but they come out with new and interesting angles all the time. They're showing suspension and brake closeups at speed of late. Good stuff.

ruffy

ty

analogmike

My gt3 cups' sequentials don't seem to have any neutrals between gears though, if you press on the gas while braking the car will just accelerate, very tricky... I have downshifted without blips several times when I missed or forgot, and it went in ok, but I have never tried downshifting without the clutch. I will need to ask a pro driver who has done this in the cup car for the proper technique. But the manual says that using the clutch is recommended so I tend to believe the factory.

Bryan Watts

There has to be some point, however short, at which the transmission is between gears in a traditional sequential. We haven't yet produced a transmission with instant gear changes in a race car...even a twin clutch transmission has a point at which no power is being placed to the ground. Even the fast shifting F1 boxes have a point at which no power is going to the ground. Actually, I guess Zeroshift claims to have an instant shift technology, but I've yet to see it applied in Motorsport. I remember rumors about it being adapted to a Corvette years ago, but haven't heard anything new in a long time.

I believe the manuals recommend as much for most every sequential or race transmission I've come across. Perhaps it's a liability issue, or perhaps it's better for that particular transmission from a wear standpoint...that doesn't mean that it's not faster to shift without the clutch. Wear isn't such a big deal to a team who breaks their transmission down after every race, and in the case of the dog-ring box I ran in FM, we found less wear from shifting without the clutch. The advantages of LFB done well are hard to argue against when you look at the friction circle, so I suspect there are Pro teams out there shifting the Porsche box without the clutch.

claykos

I've never driven a sedan car with a sequential - I imagine it's possible, but requires exact timing.

I would not recommend it with a synchro box - but it is possible. I have done it on my BMW street car just screwing around before. The thing is, with a synchro box you have to be PERFECT or else it doesn't want to go into gear.

Dog ring boxes are designed with only a few "dogs" that engage the gears, and lots of space in between these dogs. Basically, if you are in the ballpark of the RPMs it would just slide right into gear. Also, if you are not applying power, it easily slips out of gear since there isn't the constant mesh like in a synchro box. This is why dog boxes aren't very practical on the street because at constant speed (no accel or decel) the gears will bang back and forth against each other.

So yes, the idea is you slide it out of gear, while it's in neutral you blip the throttle and slide it down to the next gear. When you get good at it it's basically one fluid motion and you just have to time your blip properly. Many NASCAR type cars that have been converted for road racing actually have the pedals set up so it is not possible to heel and toe because the steering column goes between the gas and brake pedal. You HAVE to left foot brake and downshift without the clutch!

Veloce Raptor

The one I drove the other day was (obviously) nopt mine, so I used the clutch with EVERY downshift. The trickiest part was timing the blip, since the instant you nudge the lever forward, BAM it is immediately in the next lower gear. So I had to be slightly later with the blip, literally the instant I touched the lever & clutched. After I figured out the timing (2 or 3 easy 50% laps) it was easy peasy.






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Bryan Watts

That's the thing, whether you are shifting with or without the clutch, the blip happens at the same time since there's no "neutral" where you can leave the shift lever while you get the blip over with. If you can execute a proper blip on a downshift using the clutch, you can do one without as well.

Veloce Raptor

Yes, exactly. I had never driven a sequential before at speed, so I wanted to get it right. It was definitely different than the 6 Cup!!






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