Gearbox strength

[Lauren 2259]

19 hours ago, Bfranklyn86 said:

Why is it better to change slowly? Just for gearbox longevity?

Yep, that's it really and not missing gears of course. Gearboxes are expensive to repair so worth taking care of I think.

[Church 209]

Just back from shop having installed mtec shift springs, and perrin shifter mount bushing and transmission support mount. Funnily i don't hear anymore slight metallic sound when engaging 2nd, that i mentioned in posts above. So maybe it wasn't worn synchro but something else.

P.S. Now from my own experience i can also tell that those mods above realy noticeably improve shifting feel. Yes, they also add NVH (quiet extra whine like when driving in reverse or 1st (though quieter, and at higher speeds drowns in tire noise anyway), and gear shift "clicks" are twice louder), but actual feel of gearshifts now seem very good. Gears subjectively are engageable easier (including 2nd. But have yet to try after it's been stationary for longer time then two hours at shop, for "cold 2nd" test)/more precise feel/no slack.

[Church 209]

Not missing gears imho is closer to what rev-matching is. - Each synchro has to work(heat up/wear) less to even out engine/shaft speeds prior gear is engaged if difference is divided by closer gears synchros switched in sequence.

Let's say, if synchros do well with evening out difference of 500rpm, it's 8x times more work(&heat & wear) to even out 4K rpm difference, like if with some 1-2-6 gearswitches, or downshifting after heavy braking, it's worth to wait prior 2nd gear upshift to 6th extra second or two for engine rpms to drop before put in 6th, and throttle-blip when heal&toe-ing in 2nd case. Worth also blip throttle after coasting in neutral.

[Lauren 2259]

1 hour ago, Church said:

Not missing gears imho is closer to what rev-matching is. - Each synchro has to work(heat up/wear) less to even out engine/shaft speeds prior gear is engaged if difference is divided by closer gears synchros switched in sequence.

Let's say, if synchros do well with evening out difference of 500rpm, it's 8x times more work(&heat & wear) to even out 4K rpm difference, like if with some 1-2-6 gearswitches, or downshifting after heavy braking, it's worth to wait prior 2nd gear upshift to 6th extra second or two for engine rpms to drop before put in 6th, and throttle-blip when heal&toe-ing in 2nd case. Worth also blip throttle after coasting in neutral.

The best way to preserve synchros, is not only rev matching which I do along with heel and toeing (same thing) but to always change up or down one gear at a time. Never block shift, it's poor technique. Also never coast in neutral. 

[Bfranklyn86 52]

3 minutes ago, Lauren said:

The best way to preserve synchros, is not only rev matching which I do along with heel and toeing (same thing) but to always change up or down one gear at a time. Never block shift, it's poor technique. Also never coast in neutral. 

Why not coast in neutral?

[Lauren 2259]

1 hour ago, Bfranklyn86 said:

Why not coast in neutral?

It's more because you are not in control of the car. Also when in neutral you use fuel, when slowing down in gear you do not. 

[Church 209]

Also when in neutral there are less mechanical losses due no need to turn gear shafts and engine itself at higher then idle rpms. And if one wants to keep same speed (not engine braking) fuel will be fed anyway. So it's choice between neutral / clutch-out or keeping accel pedal light pressed. Clutch out will wear it's bearing, feeding less but still feeding fuel will not be more economical.

BTW, scenario of "neutral coasting" - i meant mostly downhills, where hill steepness is mostly sufficient to keep speed constant when self-rolling. Of course for downhills in general there are also exceptions, if they are TOO long variable speed or TOO steep, where one needs to use brakes, and by then it's really better engine-brake to not overheat brakes.

From your described reasoning not-in-control imho is most important one (though i'd change 'not' to 'less'), and in city traffic where one has worse visibility behind misc objects like trees/hauses, indeed it's better to not lessen options of available emergency-maneuvering to just steer around & brake due extra lag needed to put into gear. But on highways, with visibility far ahead? Imho - why not.

[Rich 378]

18 hours ago, Lauren said:

The best way to preserve synchros, is not only rev matching which I do along with heel and toeing (same thing) but to always change up or down one gear at a time. Never block shift, it's poor technique. Also never coast in neutral. 

I block shift all the time (on the road at least); I don't see why it's poor technique - it's recommended by advanced driving organisations and police instruction. It shouldn't increase wear over sequential shifting if you're rev matching correctly, if anything it would reduce it as you're engaging fewer synchros.

[Lauren 2259]

11 minutes ago, Rich said:

I block shift all the time (on the road at least); I don't see why it's poor technique - it's recommended by advanced driving organisations and police instruction. It shouldn't increase wear over sequential shifting if you're rev matching correctly, if anything it would reduce it as you're engaging fewer synchros.

It's poor technique. Just because advanced driving organisations and the police teach it doesn't mean it's good. Remember how both tell you how to use the steering wheel? The better way is to go through all the gears, less issues with slipping clutches and wear on synchros if you go a gear at a time. It's much harder to rev match when going down more than one gear at a time. I learnt this when racing back in 2004 and would typically go from fourth to third and then to second, heel and toeing whilst in the braking zone for a corner. It's hard because you have to learn to do it quickly, but it's the way to do it. 

[Rich 378]

On track, I always sequentially shift, especially into corners.

However on the road I'm rarely trying to late brake to anywhere near that extent, and also block shifts are more often upshifts (i.e. accelerate in third then shift up to fifth or sixth to cruise) which just doesn't happen on track. The comparison just doesn't work. You've still not explained why it is poor, so it's just a he said, she said as to who is right. Racing analogies only take you so far as good road driving is about observation and planning (i.e. avoiding billies) rather than piling into corners at 10/10ths and getting every last millisecond.

[Mike 458]

I block shift a lot on the road, and it's a piece of piss to rev match, I know how much to blip for 1 gear down so do it twice lift the clutch and the rev needle doesn't move at all. Not seeing how that can be bad for the car.

As for the advanced motoring / police saying how to hold the steering wheel... don't they say how most of us drive - ie don't shuffle the wheel because it's slow?

[Ade 517]

I got bollocked by the instructor on my 1st ever trackday for block shifting  It was a novice day and he was a bit fed up of everyone doing it. 

 

[Rich 378]

The IAM in particular used to be big on shuffling the wheel. These days they're less concerned and fixed grip is acceptable (I think the move to shorter racks and power assistance makes shuffling less necessary).

[Lauren 2259]

Well it's up to you, Rich. You don't have to be hard on the brakes to heel and toe nor do you have to be rev match on downshifts. I do tend to use a lot of engine braking by doing this on approach to junctions. I'm not in a rush, but I do it anyway. Likewise coming up the box I never miss a gear even if it is only selected briefly. I guess all of these things mean that you are using the engine better in it's power range rather then dropping the rpm significantly by block shifting. You also always have better control with engine braking and being in a gear where you have access to power should you need it. 

The push/pull method of steering is seriously outdated and goes back to the road handbook of the 1930's when steering was unassisted and wheels were huge. Quite frankly it's simply downright dangerous for a number of reasons. One is the lack of feel, two you don't know where the wheels are pointing and thirdly you can't react quick enough. 

I agree observation is everything. I learnt during my racing instruction to look ahead and use my peripheral vision. Much better than moving your head around all the time. 

[Deacon 1357]

Seems the Miltek / Bridge to Gantry team don't think they're the best either

Although, probably just none of them can drive...