Engine Braking - Not Recommended (if you arent rev matching)
10-27-2013, 12:30 PM
#51
Driving my unreliable rx8
10-27-2013, 01:11 PM
#52
Registered
10-27-2013, 04:12 PM
#53
Rotary Evolution
add in all the debris from the grinding and the transmission isn't going to be liking you in the driver seat. i'm sure he will also say he never grinds a shift, ever.
had to drive my turbo II the other day without the clutch when the master decided to give up and it isn't something i would do everyday.
hell, you could get a car rolling without the clutch too, except you just ate through half of the first gear syncro. perhaps when he does spit a transmission and prices how much it is to fix the 6 speeds he might reconsider being ignorant. but you know, people like to talk and either he is full of crap or his cars are total piles after he is done with them.
Last edited by Karack; 10-27-2013 at 04:18 PM.
10-27-2013, 09:40 PM
#55
Driving my unreliable rx8
probably quite a few, why anyone would think that clutchless shifting isn't harmful is ignorant. it sacrifices the syncros versus minor drag on the clutch disc for what? so you can say you do it just fine? heh.
add in all the debris from the grinding and the transmission isn't going to be liking you in the driver seat. i'm sure he will also say he never grinds a shift, ever.
had to drive my turbo II the other day without the clutch when the master decided to give up and it isn't something i would do everyday.
hell, you could get a car rolling without the clutch too, except you just ate through half of the first gear syncro. perhaps when he does spit a transmission and prices how much it is to fix the 6 speeds he might reconsider being ignorant. but you know, people like to talk and either he is full of crap or his cars are total piles after he is done with them.
add in all the debris from the grinding and the transmission isn't going to be liking you in the driver seat. i'm sure he will also say he never grinds a shift, ever.
had to drive my turbo II the other day without the clutch when the master decided to give up and it isn't something i would do everyday.
hell, you could get a car rolling without the clutch too, except you just ate through half of the first gear syncro. perhaps when he does spit a transmission and prices how much it is to fix the 6 speeds he might reconsider being ignorant. but you know, people like to talk and either he is full of crap or his cars are total piles after he is done with them.
87 Pathfindern 300K
92 240Z, 150K
I'm not saying that it's causing no harm at all, but just driving causes harm peroid. Hell I don't know anyone who uses the clutch on a motorcycle either to shift.
Ask just about anyone with a Class A CDL and they are taught to shift with out the clutch. It's not smooth if you aren't used to it but it's not half bad if you are.
10-27-2013, 11:51 PM
#57
kevin@rotaryresurrection
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Well 750K of them were on one vehicle a Kenworth K800.
87 Pathfindern 300K
92 240Z, 150K
I'm not saying that it's causing no harm at all, but just driving causes harm peroid. Hell I don't know anyone who uses the clutch on a motorcycle either to shift.
Ask just about anyone with a Class A CDL and they are taught to shift with out the clutch. It's not smooth if you aren't used to it but it's not half bad if you are.
87 Pathfindern 300K
92 240Z, 150K
I'm not saying that it's causing no harm at all, but just driving causes harm peroid. Hell I don't know anyone who uses the clutch on a motorcycle either to shift.
Ask just about anyone with a Class A CDL and they are taught to shift with out the clutch. It's not smooth if you aren't used to it but it's not half bad if you are.
Compares driving style to that used in a diesel powered semi truck equipped with a 12 speed transmission engineered to hold 1000ftlb and pull 50k lbs for 1 million miles between service intervals.
TOTALLY THE SAME THING BRO, TOTALLY.
10-28-2013, 12:09 AM
#58
Driving my unreliable rx8
RR, I realize there's a huge differance, But just because a persons driving style is different doesn't make it wrong. The glass trans is still going pretty good at 140K miles. I guess I will see just how fragile it is when it finally goes.
10-28-2013, 10:11 AM
#59
Rotary Evolution
motorcycles don't even have syncros, shifting a bike with or without the clutch isn't in the same realm as a car with a completely different gearbox configuration. i shift my bikes all the time without the clutch since it makes little difference either way.
i can drive a car without the clutch for an hour without getting a grind, but inevitably you WILL grind gears shifting without the clutch. quite often when compared to actually using the clutch, which i might do about once a year and i'm just not focused on driving at a particular time.
i can drive a car without the clutch for an hour without getting a grind, but inevitably you WILL grind gears shifting without the clutch. quite often when compared to actually using the clutch, which i might do about once a year and i'm just not focused on driving at a particular time.
Last edited by Karack; 10-28-2013 at 10:17 AM.
10-28-2013, 04:01 PM
#60
Registered
10-29-2013, 11:49 AM
#61
A dog box is identical in function to a synchromesh. The only difference is the synchromesh has a conical clutch with a tooth gate before the actual dog engagement, and a synchromesh has lots, lots more teeth than a dog. A dog box with a quick-shift rebuild kit on it might only have 6 teeth on the face dog. A synchromesh can have 30 or more. The gear-to-gear RPM delta (engagement window, if you will) is typically an order of magnitude smaller on a synchromesh - you might need to be within 200 RPM of your target road speed for engagement, while a dog box only need to be within a 2,000 RPM window. That means you can bang an upshift from 9,000 to 7,000 RPM in a dog box, but not in a synchromesh (cshh cshh, hey metal bits are coming off!). If you can get the synchromesh to that 200 RPM window every time with very smooth hands, it won't hurt the rings or the faces very much at all.
Last edited by MadCat360; 10-29-2013 at 11:52 AM.
10-29-2013, 03:21 PM
#62
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I think we can all agree that for a road-going car with synchros, using the clutch to up- and downshift is a good idea. Upshifting should see so little slip that it's negligible wear anyway, and downshifting you can use the throttle to match the engine speed to wheel speed and avoid too much slip. Or, just brake with the clutch and replace it sooner. If you use it harder, you'll obviously have to replace it sooner.
10-29-2013, 03:29 PM
#63
I think we can all agree that for a road-going car with synchros, using the clutch to up- and downshift is a good idea. Upshifting should see so little slip that it's negligible wear anyway, and downshifting you can use the throttle to match the engine speed to wheel speed and avoid too much slip. Or, just brake with the clutch and replace it sooner. If you use it harder, you'll obviously have to replace it sooner.
10-30-2013, 03:03 PM
#67
Registered
also by going down one gear each time allows you to know what gear you should be in for which corner so you wont be dumping clutch at wrong gear locking up the back tires.
10-30-2013, 03:14 PM
#68
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I'm sure they are referring the narrow gap of racing where the driver is skilled enough to know the gear they need and rich enough to have transmissions to spare, but poor enough that they don't have a sequential transmission.
Beginners should still go gear to gear because they are learning, and pros go gear to gear because the transmission is sequential.
...and you can't lock the rear tires by clutch dumping at the wrong point on a downshift. Slide them yes, lock them, no. The engine would have to be shut down and not rotating for them to lock.
None of this applies to professional autocrossers of course.
Beginners should still go gear to gear because they are learning, and pros go gear to gear because the transmission is sequential.
...and you can't lock the rear tires by clutch dumping at the wrong point on a downshift. Slide them yes, lock them, no. The engine would have to be shut down and not rotating for them to lock.
None of this applies to professional autocrossers of course.
12-28-2013, 08:03 PM
#69
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Engine braking is a good thing. If you wear out your clutch prematurely by engine braking, you are doing it wrong, and will cause more problems to your engine, not just the clutch system. By all means, drive your car how you want, I don't pay for your repairs, but engine braking is not inherently damaging, and is a safe way to slow a car while avoiding possibly overheating brake pads, ie, in the mountains.
12-30-2013, 06:26 PM
#71
I didn't realize that I have shifted into second, of course, I feared that I have blown my engine the moment Ihave come into a complete stop, expecting steam and fluid splatter on the windshield. I'll never forget that moment when the engine rev'ed, heard the redline beep, then the total shut down of the engine. It was frightening because my 12 month MAZDA reman' engine warranty have already expired.
12-30-2013, 11:36 PM
#72
kevin@rotaryresurrection
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This happened to me three months ago on an uphill. I was in fifth gear at 71-75 mph, rev-matched then downshifted, instead into forth I ended up moving it into the second gear. Obviously, the ECU just cut the engine off and I had to cruise my way to the emergency lane while I was still at an uphill.
I didn't realize that I have shifted into second, of course, I feared that I have blown my engine the moment Ihave come into a complete stop, expecting steam and fluid splatter on the windshield. I'll never forget that moment when the engine rev'ed, heard the redline beep, then the total shut down of the engine. It was frightening because my 12 month MAZDA reman' engine warranty have already expired.
I didn't realize that I have shifted into second, of course, I feared that I have blown my engine the moment Ihave come into a complete stop, expecting steam and fluid splatter on the windshield. I'll never forget that moment when the engine rev'ed, heard the redline beep, then the total shut down of the engine. It was frightening because my 12 month MAZDA reman' engine warranty have already expired.
12-31-2013, 11:10 AM
#74
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I sometimes get the impression that stirring a manual transmission correctly is a dying art. My dad taught me the fundamentals of rev matching while I was learning to drive our family car. Slipping the clutch was verboten, except when starting out from a complete stop. Dad would climb all over me if I shifted down a gear and then slipped the clutch to bring the engine RPM's up.
So here I am, decades later, and I rev match without even thinking about it - gearing up or down.
Another thing. When I bought my first RX-7 back in '85, the salesman specifically told me that it was OK to drive the car hard - it was built for it - a sports car actually. Now, he wasn't suggesting abuse. A sports car can be driven in a very sporty manner without abuse. Excessive slipping of the clutch, dragging the brakes, jerky high rev starts, etc., is abu$e. Drive smoothly and have fun!
So here I am, decades later, and I rev match without even thinking about it - gearing up or down.
Another thing. When I bought my first RX-7 back in '85, the salesman specifically told me that it was OK to drive the car hard - it was built for it - a sports car actually. Now, he wasn't suggesting abuse. A sports car can be driven in a very sporty manner without abuse. Excessive slipping of the clutch, dragging the brakes, jerky high rev starts, etc., is abu$e. Drive smoothly and have fun!
Last edited by 1.3L; 12-31-2013 at 11:59 AM. Reason: 2 typos