How to drive on street and track to preserve the gearbox ?

fastx19 said:
Ok, I will offer a different view point then. After racing both the 4 and 5 speed boxes, to me the weakest link is drive shafts. I have two rules when driving the car, 1) No hard drag race launches, and 2) don't force the car into gear, use some grace and finesse (i.e., don't drive it like a 4 speed Hurst shifter... ) For those old American classic muscle car people, that would make sense.

The only time I had a transmission failure was my fault. I had the wrong suspension on for an autocross and the rear tires came into contact with the wheel arch. The weakest link in that whole scenario was the 3rd gear to output shaft. Lost a bunch of teeth and had to get a new input and lay shaft for the transmission.

I also had a very short gear box in my Race X originally when I first got it. It was ridiculous, you could go full out and through the first three gears and not be over 35mph... I would bang through those as fast as I could, never had an issue.

However, as Steve H would probably attest to, preparation of the components in the transmission makes all the different in the world. Without giving away secrets, there are areas of improvement in the machining and surfaces of items which can make a huge difference in how well the system shifts. For the 4 speed FWD, I found the casting of the case from a Yugo had much better oil flow than the ones from Fiat, so little things like that go a long way. Oh, good throw out bearing, a clutch master/slave which is properly bleed and works very well, and the list goes on and on.

Hope this helps.
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Data point, over the many years of LeMons endurance racing, never had any issues with the Fiat cv joints (5 speed, 86mm bolt circle) or axles. This was with the oem 1500cc power train or later PP rotary with Porsche 901 transaxle. This could be due to the care in cv joint prep and lubricants used. What is well known, the 4 speed outer cv joints DO fail under higher than oem power as they are essentially direct from the Fiat 128 and never designed to transmit the levels of power a truly "hot rodded" Lampredi SOHC can deliver.

Over the many LeMons races, the Porsche/Lobo 78mm bolt circle cv joints were problem prone, they wore out often (even with the same care in prep and lubricants used in the 86mm Fiat cv joints) and the M8 screws were a constant "getting loose" problem due to design. Porsche 901 uses 78mm bolt circle with four M8 socket head cap screws and two large roll pins. Technically, theoretically correct as the pins locate the joint, M8 cap screws tension the joint.. except the shock load levels are much higher than the Porsche engineers expected and designed for. These M8 cap screws were re-torqued after each event.. and they were always loose. The worry was if the joint failed causing a whipping axle inside the power train compartment... that mode of failure was very real and very possible.

The rotary powered LeMons exxe uses modified stock exxe axles to fit the 78mm Porsche cv joints with oem 86mm Fiat cv joints on the outer. The outer stub axles are from the Lancia Scorpiacarlo as they are designed for bolt/washer/nut instead of the threaded flange on the stock exxe. The oem Fiat/Lancia socket head bolts/nylocks/washers were replaced with aero spec MS21250 bolts with matching nuts and countersink washers. These never came loose or had any issues for all the years of LeMons endurance racing..

Previous discussion on "axles". post/discussion was from 2008.. Since then, after procuring parts from the Lancia and comparing then to the exxe rear uprights.. they are identical in every way and directly interchangeable in more ways than believed. This is fact as done and proven in the LeMons racer..

Breaking axles

Who here has broken axles? My friend (who is also building a turbo X1/9) has a turbo 1.5l Yugo and has been OK with his axles, but the X1/9 itself would be alot harder on axles because weight transfer will increase traction instead of reducing it.
xwebforums.com


Bernice
 
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Double clutching is from a time before syncros...(and ridiculous Fast and Furious movies) All that's doing now is adding time and effort to your shifting.. What is the mechanical benefit? When the clutch is pressed it is disengaged, why release it and re disengage it during the same shift? It's effect is not cumulative, it will be as disengaged as it was the first time you pressed the clutch..... Just a smooth shift from one gear through neutral to the next is all you need. Not really a 'pause', but don't smash right past neutral either, it's definitely a two beat maneuver... Never had a ground gear shifting that way, up or down...
 
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Rupunzell said:
Data point, over the many years of LeMons endurance racing, never had any issues with the Fiat cv joints (5 speed, 86mm bolt circle) or axles. This was with the oem 1500cc power train or later PP rotary with Porsche 901 transaxle. This could be due to the care in cv joint prep and lubricants used. What is well known, the 4 speed outer cv joints DO fail under higher than oem power as they are essentially direct from the Fiat 128 and never designed to transmit the levels of power a truly "hot rodded" Lampredi SOHC can deliver.

Over the many LeMons races, the Porsche/Lobo 78mm bolt circle cv joints were problem prone, they wore out often (even with the same care in prep and lubricants used in the 86mm Fiat cv joints) and the M8 screws were a constant "getting loose" problem due to design. Porsche 901 uses 78mm bolt circle with four M8 socket head cap screws and two large roll pins. Technically, theoretically correct as the pins locate the joint, M8 cap screws tension the joint.. except the shock load levels are much higher than the Porsche engineers expected and designed for. These M8 cap screws were re-torqued after each event.. and they were always loose. The worry was if the joint failed causing a whipping axle inside the power train compartment... that mode of failure was very real and very possible.

The rotary powered LeMons exxe uses modified stock exxe axles to fit the 78mm Porsche cv joints with oem 86mm Fiat cv joints on the outer. The outer stub axles are from the Lancia Scorpiacarlo as they are designed for bolt/washer/nut instead of the threaded flange on the stock exxe. The oem Fiat/Lancia socket head bolts/nylocks/washers were replaced with aero spec MS21250 bolts with matching nuts and countersink washers. These never came loose or had any issues for all the years of LeMons endurance racing..

Previous discussion on "axles". post/discussion was from 2008.. Since then, after procuring parts from the Lancia and comparing then to the exxe rear uprights.. they are identical in every way and directly interchangeable in more ways than believed. This is fact as done and proven in the LeMons racer..

Breaking axles

Who here has broken axles? My friend (who is also building a turbo X1/9) has a turbo 1.5l Yugo and has been OK with his axles, but the X1/9 itself would be alot harder on axles because weight transfer will increase traction instead of reducing it.
xwebforums.com


Bernice
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Agree here. Most of the issues were the M8 bolts backing out. However, I did have two axle shafts break on me (At the time, Autocross was the focus, and I was running a 20x9.5x13 cantilever slick on it.) Lots of traction. A couple of the races had a start which was best suited to a "dump the clutch and go" approach vs. being able to get the car rolling before hammering it. That is when the axles died. Dead stop, hard acceleration, big ol' tires. Now, I did manage to stop it later on by having the drive shaft cyro treated. Some may poo poo this option, but it seemed to work for me. No more issues with axles.
 
I do 2 things. 1st change gear slowly. You if you get the right pace you can feel the right pressure to apply when changing gear. A minute pause in neutral seems to help too. Its all about feel and not rushing.
2nd don't move into 1st while the car is in motion. I read that this doesn't do the reverse idler any good (I am sure gearbox experts here can give more detail) but either way there is little value in going into 1st while moving, 2nd is enough, or stop and go into 1st.

For street use this should be enough to allow you to enjoy your car and extend the life of the gearbox.
 
Following on from all the others.

I take my time in shifting. There is no way you will gain time by shifting an X quickly, there just isn’t enough power for a fast shift to make a difference in time or real acceleration difference.

A way to think about it is there are three motions in a shift. The movement from the gear you are in. Neutral. Moving into gear you are going into. Each of these are a movement, separate and different from each other. They are intentional, deliberate and done with accuracy.

When upshifting there is no need for double clutching in my mind. Down shifting does want double clutching which is easily accomplished by rolling your right foot while on the brake onto the accelerator pedal which is ideally set up to assist in this. Again from a gear change perspective there are again the three defined motions which are inter related with the clutch motion, the brake pedal and accelerator pedal in a lively two step dance.

Clutch take up is smooth, not fast and never jerked on the way out. The clutch should be fully depressed to the floor during any gear change. When coming up through the engagement point, don’t slip the clutch. When done the foot is off the pedal and on the floor, the dead pedal or hovering over the pedal in preparation for the next change. Ones foot must never rest on the clutch pedal.

When the clutch is coming up, having engaged a gear, pressing the accelerator so the rising rpm matches the chosen gear’s need as the clutch engagement point and the rpm needed, coincide.

I have yet to replace a clutch or a transmission on one of my cars in the 45 years I have been driving with as much as 195k miles on some of the cars.
 
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Mark_Toro said:
About 55 seconds in:


One of my most favorite videos ever.
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Those WRC cars have straight cut gear boxes and dog drive gears, no synchros ..

They can be shifted with no clutch or off throttle followed by a quick/smooth maneuver of the shifter..

Properly done, dog drive gear boxes will change gears WAY faster than any synchro box..

Bernice
 
Toe/heel is a far more important driver skill than "double clutch" as this combines braking/shifting into the correct gear/accelerating out of the corner at the best corner exit point.. Note here, the accelerator pedal on the exxe & Scorpiacarlo and others has a slight curve at the bottom to aid in toe/heel... Not found any modern motos with this specific feature which is extremely telling.

Use the syncros properly, that is what they are designed in to do.

Bernice
 
Lowtechprime said:
Double clutching is from a time before syncros...(and ridiculous Fast and Furious movies) All that's doing now is adding time and effort to your shifting.. What is the mechanical benefit? When the clutch is pressed it is disengaged, why release it and re disengage it during the same shift? It's effect is not cumulative, it will be as disengaged as it was the first time you pressed the clutch..... Just a smooth shift from one gear through neutral to the next is all you need. Not really a 'pause', but don't smash right past neutral either, it's definitely a two beat maneuver... Never had a ground gear shifting that way, up or down...
Click to expand...

In my double clutch comment, I failed to explicitly state the rev-matching is part of the double clutch operation. That rev matching is the key to double clutching doing anything. Just double pumping the clutch on the way down and not rev-matching is pointless. Agreed.
 
Another point is the effort one applies to the gearshift.

At most one should use thumb and forefinger only to shift from gear to gear. The X transmission doesn’t need much guidance in most shifts aside from 5th due to the spring loading towards 3/4. Grasping the shift knob with ones entire hand allows you to apply too much force and one will miss the transmission trying to balk and overpower the synchromesh.

Personally I find the OE early black spherical knob ideal on all of my Fiats. I dumped the beer tap on my early 1500 the day I bought it.
 
Bernice - that was an interesting watch. I learned a couple of things:
  • I must be doing something right. I think I am working the pedals like Ayrton!
  • My new pair of driving shoes are going to be loafers! :)
 
The phrase I use when teaching people to shift an X1/9 is "mechanical sympathy". It requires the driver to learn the feel of the engagement and the amount of speed and force applied to allow the synchronizers to do their work. Upshifting is less critical than downshifting. Downshifting requires the input shaft to be accelerated by the synchronizer to match road speed. This is where "double clutching" came from. Engaging the clutch, with the transmission in neutral, while reving the engine, accelerates the input shaft rpm so it more closely matches the road speed in the lower gear.

Its not necessary to double clutch the X but pausing the shifter between gear positions, and applying only necessary pressure to engage the lower gear, will allow the sychronizer to do its job.

An X1/9 transmission, in good condition, can be shifted quickly if the driver uses a light touch and learns the limits of speed and force to be applied.

This is an in-car video from my MR2 autocross car. I built this transmission (a close ratio gearset with synchronizers) specifically to live in this environment. It has extensive customization to make this work. It gets driven like this on every run at every event. I have been driving it like this for many years. It does get refreshed each season but has only had one minor failure in many seasons of competition. Note that upshifts are as quick as I can make them. Data shows that from peak thrust to peak thrust takes about half a second. If you watch my feet on the pedals you will see downshifts are done without the clutch using a crude revmatch while left-foot braking. I developed this technique driving my X1/9 racecar which had a mostly stock 5 speed.

Note: this is a demonstration of a total lack of mechanical sympathy for the sake of lap times.

 
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Bjorn Nilson said:
"total lack of mechanical sympathy"😂😂 what a wonderful expression for gearbox abuse.
I do understand you refresh the box once per year.
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Racecars are tools. I don't abuse the transmission but I don't sacrifice speed for "mechanical sympathy". I am trying to win in the most competitive environment in the sport. I will push everything to the limits to extract every bit of performance the car has. And that's not limited to the transmission. The engine, brakes suspension, tires, etc..

The 'lack of mechanical sympathy' and 'outright abuse' are two different things. To be sure, I could easily break the transmission if I tried. But the goal is ultimate lap time and if that means using up the synchros to do it that's just the price of winning.
 
Steve Hoelscher said:
Racecars are tools. I don't abuse the transmission but I don't sacrifice speed for "mechanical sympathy". I am trying to win in the most competitive environment in the sport. I will push everything to the limits to extract every bit of performance the car has. And that's not limited to the transmission. The engine, brakes suspension, tires, etc..

The 'lack of mechanical sympathy' and 'outright abuse' are two different things. To be sure, I could easily break the transmission if I tried. But the goal is ultimate lap time and if that means using up the synchros to do it that's just the price of winning.
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I know exactly what you mean Steve. I just liked the way you expressed it.
 
Steve - I never get beyond "extract every bit of performance the driver has" when I autocross. No room to blame any system on the car. 😂

I run in SM with the supercharged GTV6 on street tires. I've actually finished ahead of several others at Nationals - because they broke.

For anyone who hasn't run a competitive autocross, you cannot believe how brutal they are these days. Even (maybe especially) in the stock classes. Back in the 80s I was able to come third in points for the year, NNJR SCCA D stock running a stock Spider on street tires. Not possible any more.
 
Mark_Toro said:
Steve - I never get beyond "extract every bit of performance the driver has" when I autocross. No room to blame any system on the car. 😂

I run in SM with the supercharged GTV6 on street tires. I've actually finished ahead of several others at Nationals - because they broke.

For anyone who hasn't run a competitive autocross, you cannot believe how brutal they are these days. Even (maybe especially) in the stock classes. Back in the 80s I was able to come third in points for the year, NNJR SCCA D stock running a stock Spider on street tires. Not possible any more.
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There are two different categories of autocrossers: people that are there for the primary purpose of having fun, and people who are there for the primary purpose of winning. Different mindsets with different approaches to the sport.

When I started doing trackdays, it was just for fun although I did note my lap times and always wanted to improve and be quicker than everybody else. Then I started doing Time Attach/Time Trials, and the competitive instinct quickly took over. :)

Yes, the competition level in the sport has come a very long way. I recently drove the current SM2 National Championship winning car. Among other things it has aero designed with extensive CFD development and testing.
 
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More power to you. I'm definitely too broad focused to be serious. I'll tour with the same car I autocross. And I'll autocross anything that will pass tech. I do like watching the serious guys and have found that the are willing to share if you catch them at a relaxed moment (not in the red mist)

I don't think I have found a better venue to develop driver skills. Things I learned in autocross have saved my but on the street.
 
Mark_Toro said:
More power to you. I'm definitely too broad focused to be serious. I'll tour with the same car I autocross. And I'll autocross anything that will pass tech. I do like watching the serious guys and have found that the are willing to share if you catch them at a relaxed moment (not in the red mist)

I don't think I have found a better venue to develop driver skills. Things I learned in autocross have saved my but on the street.
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Back in my early days of autocrossing, as a poor college student running my tired '77 X1/9 street car, I was mid pack and chasing the "fast guys". Then our region hosted a Divisional Championship event and all of the National Caliber drivers from the south eastern US showed up. I remember watching a guy driving a C Stock car run faster times than our fastest local guy in a Formula Ford, on slicks. I was in total awe of the guy. I knew then I wanted to run against those guys at National events. They taught me some very harsh lessons and I credit them today as both my inspiration and nighmare.
 
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