Shifting without the clutch on the street

Transmission to Rear-end

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Post by BillyShope » Tue Sep 11, 2007 11:00 am

The '56 Corvette owners were pretty much forced into this sort of thing. With a 2.2 NON-synchro first and a 3.55 rear, you could go over 60 in first. But, if you got caught below sixty after shifting out of first, some kid in a delivery van could make you look awfully slow.
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Post by 77cruiser » Thu Sep 13, 2007 11:44 am

mudracer wrote:its my personal opinion that every race car driver be forced to drive an old Mack with a 5 over 4 (brownie) and very poor brakes for about a month.


That will either make you confident, or make you understand that you dont want to be a racecar driver.
Knee on the steering wheel shifting 2 handed!!!
Trying to brake with the leg that has the knee on the steering wheel!!
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Post by sc68z28 » Fri Sep 14, 2007 11:43 pm

I have found that my face-plated/dog-ring G-force, shifts better without using the clutch. Down shifts require RPM matching, upshifts just back off a little and pull/push, it clunks right in. If I use the clutch it grinds its way in.

At the drag strip I'm having a mental block, my right foot tents to stay on the floor. I've been told to hank hard and it will come out, the back cut seems to be holding it in. I'm chicken to pull to hard on it :oops: So I've been tapping the 2-step button to get it out of gear, then it goes right in the next at a lower RPM than the 2-step is set (6K). The problem with that is the O2 sensor sees that as a lean condition.

Sorry I'm rambiling, back to the trans, here's a pic inside after 1600 miles and about 60 passes.
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Post by Ed-vancedEngines » Sat Sep 15, 2007 1:03 am

About not being able to shift that tranny with a clutch;
I'll bet you can when you get some practice in double clutching. You tap the clutch enough to get it out of gear and let up, them you once again mash the clutch a little more for it to drop into the next gear. It takes a little practice and you have to do it quick or revvs will drop too fast to get in gear, so you will have to clutch quickly bump revs up and drop it in gear when revvs are right to get a good gear syncro mesh.

At the track just lightly tap the clutch in while holding a hard and firm grip on the shifter pulling or pushing with all your might before you tap the clutch. You do this and it will likely quickly drop right in. All you need the clutch to do is to release the pressure while you are manhandling the stick, it will go right in the next gear, or at least it should.


Lol Jim,
Next time try this my way.
Instead of holing wheel with kneee or leg, try you arm or actually your shoulder. Don't stick your arm through the wheel spokes like I have seen some guys do, that can hurt and you can't turn curves while shifting if you arm is in the wheel spokes.

I push my upper arm against the wheel, which frees up both hands and lower arms and wrists to do the shifting as needed. I hit the aux box up to top gear, with my right hand and quickly switch right hand to main box and left hand to auxillary box so I can keep my timing of which box to drop in when.

Doing it that way you can control the wheel coming back during turns or on mountain curves. What was fun and frankly I can't tell you how I did it but I did. That was doing all my up shifting and down shifting with two sticks while still talking on the CB Microphone and steering the truck in turns. Like I say. I did it, but for the life of me years later can't figure out how I did. I do kow that I used to joke about it on the CB talking about me having 4 arms. lol

I preferred a good Mack Quadraplex or a good 4 & 5 or 4 & 6 Brown Lipe tranny to just about anything. I could walk and talk going up the hills when the guys with the Roadrangers couldn't shift. lol. I also did some 4 & 5 stuff in dirt trucks too. Same thing I could make them walk and talk while gaining speed and gear coming out of the dirt pits in the boggs, while the guys with therir 13 speed roadranger fullers could only do it in low-low and couldn't shift up. O' but if or when I missed a shift. That was an instant stop and strat all over. Heaven help you if you missed a shift while going up a mountain. It is a long reverse trip to where youy can get started moving again.

Ed

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Post by jstand » Sun Sep 16, 2007 9:45 am

sc68z28 wrote: At the drag strip I'm having a mental block, my right foot tents to stay on the floor. I've been told to hank hard and it will come out, the back cut seems to be holding it in. I'm chicken to pull to hard on it :oops: So I've been tapping the 2-step button to get it out of gear, then it goes right in the next at a lower RPM than the 2-step is set (6K).
Being new to the forum I'm not sure what you mean by the 2 step button.

But depending on what you are running for an ignition/ECU you can have your shifter instrumented to trigger a split second cut once enough pressure is applied to the shifter. This will unload the driveline and allow it to slip out of gear.

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Post by sc68z28 » Mon Sep 17, 2007 12:24 am

Ed-vancedEngines wrote:About not being able to shift that tranny with a clutch;
At the track just lightly tap the clutch in while holding a hard......
Ed
Hay Ed, thanks for your intrest and response. For others reading that may not be familiar with a face-plate/dog-ring transmission, they do NOT have syncros, so don't try this at home with your streetcar trans.

The trans shifts great with the clutch. It's just a little smoother without it, when I get the rpm match right. Thats about 98% of the time (street use).

At the track I run low static/base presure in the clutch, so it will slip at launch. Once I am about 20' off the line it starts to lock up, and it's better if it stays locked up. Tapping the clutch on up shifts works fine for the shift, but starts it slipping again. As we know the back-cut on the dogs, holds it in gear under load. Since I'm pigheaded and won't take my right foot off the throttle, came the idea of using the 2-step to unload the trans.

In actuallity, all I need to do is blip the throttle while pull/push and problem solved, it would come right out and it allways goes in.
---Bill.
Last edited by sc68z28 on Mon Sep 17, 2007 1:12 am, edited 1 time in total.
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Best 60' 1.28 vid, http://www.youtube.com/watch?v=1OLzx5jBo4w

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Post by sc68z28 » Mon Sep 17, 2007 1:10 am

jstand wrote: I'm not sure what you mean by the 2 step button.

:idea: a split second cut once enough pressure is applied to the shifter. This will unload the driveline and allow it to slip out of gear.
I am using the XFI ecu and a MSD digital 6 box. I'm using the second RPM limiter in the MSD as a launch RPM comtrol, AKA 2-step. It's activated by a button on the top of my shifter and is set to around 6K.

Since I shift at 6900, when I pull on the shifter and I tap the button, it cuts power enough to come out of gear. Then even if I don't release the button right away, when it sees the lower RPM of the next gear (about 5K) that is under the 6K setting, so off we go :)

This works, but on the data logs I noticed that when I use the button (MSD drops cyl.) the unburned mix is seen by the O2 as a lean condition and starts to compensate by adding fuel. The extra fuel is seen as slightly rich from 5200 to about 5500rpm. 5300 is peak torque, and a little rich on a boosted motor might not be a problem at all??? I hope :?


---Bill.
68 Camaro, Procharged 380ci, FAST EFI, GF5r trans, Advanced Clutches 7" two disc,
Best 60' 1.28 vid, http://www.youtube.com/watch?v=1OLzx5jBo4w

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Post by MadBill » Mon Sep 17, 2007 10:23 am

Oh-too-many years ago, I read of AMA motorcycle racers using a momentary mag-grounding button for WOT shifts. Tried shifting my Mom's '56 Dodge 'three on the tree" wagon wide open, no clutch by turning off the ignition key.
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Post by jstand » Tue Sep 18, 2007 8:02 pm

sc68z28,

Thank you for clarifying.

Is the trigger only set up for an on/off trigger? If it has adjustable voltage threshold for triggering (similar to ECU's from MoTec or PI) then it would be possible to trigger the cut based on pressure on the shifter.

When you hit the button you are essentially doing the same thing as the ignition cut-outs I'm familiar with. These use strain gages to make the shifter (or linkage) into a load cell. The output can then be amplified to trigger the ignition cut as soon as enough pressure is applied to the shifter to initiate the shift. The duration is usually adjustable so with some tuning the delay before getting back on the power can be minimized.

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Post by David Redszus » Thu Jan 17, 2008 11:06 am

77cruiser wrote:
mudracer wrote:its my personal opinion that every race car driver be forced to drive an old Mack with a 5 over 4 (brownie) and very poor brakes for about a month.


That will either make you confident, or make you understand that you dont want to be a racecar driver.
While I have never driven an old Mack with a 5 over 4, I can relate to the experience.

Everyone should learn how to drive without using the clutch, master the skill and then hope you never have to use it. The preferred method of learning is on someone else's car.

I can remember having to drive the last 1 1/2 hours of a 12 hr road race with no clutch and a frozen, wide open throttle. You simply learn to adapt.

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Post by My427stang » Tue Feb 19, 2008 10:56 pm

mudracer wrote:its my personal opinion that every race car driver be forced to drive an old Mack with a 5 over 4 (brownie) and very poor brakes for about a month.

That will either make you confident, or make you understand that you dont want to be a racecar driver.
At 9 years old dad taught me to drive on a quadbox Mack R-model. Unfortunately my hands were much smaller than the guy who bent the sticks to his advantage, so I had to use the arm through the streering wheel trick

Later at 11 or so I'd show off to the truckers at our shop popping gears off like an old pro :) on a U-model wrecker we had with a duplex (5 x 2 two stick) Has to be the coolest thing for an 11 yr old showing off for the adults used to 13 speeds that cant shift a 2 stick ;)

With that, I have timed a few million clutchless shifts on synchro'd trannies over the years, and I say it that way because if you are doing it right you are timing the shift to the change in input shaft speed and it doesnt hurt a thing. In essence, you are the synchro. If you cant time the shift to have the gear slip in, dont do it

The second you use force and dont "finesse it" as we used to say, its very hard on the brass blocker rings as they are trying hard to mesh two dissimilar speed gears that are much harder, only because you are in a hurry LOL

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Post by SchmidtMotorWorks » Tue Feb 26, 2008 8:53 pm

They sell kits for street bikes that cut the ignition for shifting without the clutch, real impressive.
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Post by GTRACER » Wed May 27, 2009 5:49 pm

I agree, this is a skill every racer should learn, even if it may not be the best method for every shift.

I learned the "art" of double clutch downshifting on a XK-120 Jaguar from the salesman at the dealership. By the time I got a summer job there a year later, I was chasing parts in an old Jeep. Being young and trying to look cool, we'd drive it around with the left foot on the door sill (no actual doors) and used the clutch only when needed at at stop light.

I had a clutch fork failure in my brand new '63 Sting Ray one day and was greatful that I had learned to shift without the clutch. I simply shut off the engine at the traffic light and on green used the starter to get it going again, shifting through the gears without the clutch. No trauma, no problem. It only had a couple hundred miles on it and was under warranty so I just drove it back to the dealership where they re-connected everything.

Later when running another Jag, I found this skill handy for getting into non-syncro first gear at autocrosses for extra launch around the course.

You never know when this sort of thing might come in handy. Especially with a race car. They tend to break things at the darn'est moments.
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Post by BillyShope » Wed May 27, 2009 7:26 pm

GTRACER wrote: I learned the "art" of double clutch downshifting on a XK-120 Jaguar....
Yes, as I recall, the XK-120 didn't have a synchro first and the synchro on the other gears wasn't all that great.

I had a '56 Corvette with the close ratio 3 speed (no synchro in first). It could do over 60 in first with the stock 3.55 axle, which meant that a delivery boy in a flathead six Plymouth van could make me look very slow if I short shifted from a stoplight. A quick double clutch took the smile off his face. (No, I don't approve of street racing, but, back in the fifties, "racing" up to a 45 mph speed limit wasn't that big a deal.)

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Post by MadBill » Wed May 27, 2009 7:31 pm

GTRACER wrote:..I had a clutch fork failure in my brand new '63 Sting Ray one day and was greatful that I had learned to shift without the clutch. I simply shut off the engine at the traffic light and on green used the starter to get it going again, shifting through the gears without the clutch. No trauma, no problem...
X2! My son's VW Bus broke a clutch fork 200 miles out, so I got to herd it home clutchless. Worst part was finding that one tiny town on the return route had sprouted a dozen new traffic lights since my last visit... :shock:
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