chez00
01-10-2013, 07:21 PM
This article is our opinion only. It is written from the biased perspective of a gearbox specialist and needs to be read in that context.
We get asked every now and then to recommend the right clutch. We don’t sell clutches here at Neat except for genuine Honda ones when customers want one - so we’re not going to recommend you buy the one we happen to have on the shelf or the one with the best margin in it. This is just a bit of advice from someone who works with gearboxes every day and sees the result of the wrong clutch choice all too often.
There’s a rumour out there that K series 2nd and 3rd gears are weak, for example. It’s simply not true - the problem is that the guys and girls who are breaking them are running big power with aggressive clutches and sticky tyres. These gearboxes weren’t designed for this sort of shock loading - it was never in the engineer’s debrief. Honda built the gearboxes to a specification, and when those specs are significantly exceeded, they break.
Most people have heard the equation: “cheap, fast, reliable: choose two.” With clutches, there’s a similar sort of equation. It’d be something like this:
hard shifts + aggressive clutch + more than standard power = broken gearbox.
If you don’t want a broken gearbox (or diff), driveshafts or even a broken crankshaft, at least one of the above factors needs to come out of the equation. If you have a modified engine making more power than standard, you either need to go easy on shifting or use a softer clutch to make your drivetrain last.
Abuse will kill everything eventually, so flat changing without the clutch is a sure path to destruction. That’s not what we’re talking about. When we say hard shifting, we’re talking about a “straight through” motion, not waiting for the synchronisers to completely slow the rotating mass of the gearbox down before selecting the next gear, combined with an aggressive “on-off” pedal motion. This is par-for-course on the track, but if you drive like this all the time this advice is even more important.
To sum up, our advice when selecting your next clutch is this: go for the softest possible without slippage. Think about it: a “performance” clutch will make you no faster than the standard clutch, so long as both are transferring power from the engine to the drivetrain without slippage.
Honda (and all OEM makes) invested a huge amount of R&D into developing a clutch that will not slip within the standard engine torque range, and will not damage the drivetrain. Stick to genuine or OEM equivalent if you are making standard power.
If you are making anything from 10% to 50% above standard power, go for a quality upgraded organic clutch. Spoon, Clutch Master and Exedy all make quality heavy duty organic units, and there are others too. Spoon advertise a 30% extra clamping force, while Exedy and Clutch Masters have a 70% extra or something. We’re pretty sure they’re all about the same.
If you’re making a genuine 50% extra power than standard (there’d not be too many), you need to start looking at puck options for the extra grip, depending on driving style. Go for a higher number i.e. “6 puck” rather than the 3 puck etc as the shock loads are horrendous on the lower numbered pucks, and break input shafts and pinion gears all the time. My scrap bin is full of them.
It might be helpful for people to leave some of their experiences with different clutches. To keep it neat (excuse the pun), state your engine, power figures, clutch type, driving style (street, aggressive street, drag, hill climb etc) and your experiences around it.
Hope this helps the community.
We get asked every now and then to recommend the right clutch. We don’t sell clutches here at Neat except for genuine Honda ones when customers want one - so we’re not going to recommend you buy the one we happen to have on the shelf or the one with the best margin in it. This is just a bit of advice from someone who works with gearboxes every day and sees the result of the wrong clutch choice all too often.
There’s a rumour out there that K series 2nd and 3rd gears are weak, for example. It’s simply not true - the problem is that the guys and girls who are breaking them are running big power with aggressive clutches and sticky tyres. These gearboxes weren’t designed for this sort of shock loading - it was never in the engineer’s debrief. Honda built the gearboxes to a specification, and when those specs are significantly exceeded, they break.
Most people have heard the equation: “cheap, fast, reliable: choose two.” With clutches, there’s a similar sort of equation. It’d be something like this:
hard shifts + aggressive clutch + more than standard power = broken gearbox.
If you don’t want a broken gearbox (or diff), driveshafts or even a broken crankshaft, at least one of the above factors needs to come out of the equation. If you have a modified engine making more power than standard, you either need to go easy on shifting or use a softer clutch to make your drivetrain last.
Abuse will kill everything eventually, so flat changing without the clutch is a sure path to destruction. That’s not what we’re talking about. When we say hard shifting, we’re talking about a “straight through” motion, not waiting for the synchronisers to completely slow the rotating mass of the gearbox down before selecting the next gear, combined with an aggressive “on-off” pedal motion. This is par-for-course on the track, but if you drive like this all the time this advice is even more important.
To sum up, our advice when selecting your next clutch is this: go for the softest possible without slippage. Think about it: a “performance” clutch will make you no faster than the standard clutch, so long as both are transferring power from the engine to the drivetrain without slippage.
Honda (and all OEM makes) invested a huge amount of R&D into developing a clutch that will not slip within the standard engine torque range, and will not damage the drivetrain. Stick to genuine or OEM equivalent if you are making standard power.
If you are making anything from 10% to 50% above standard power, go for a quality upgraded organic clutch. Spoon, Clutch Master and Exedy all make quality heavy duty organic units, and there are others too. Spoon advertise a 30% extra clamping force, while Exedy and Clutch Masters have a 70% extra or something. We’re pretty sure they’re all about the same.
If you’re making a genuine 50% extra power than standard (there’d not be too many), you need to start looking at puck options for the extra grip, depending on driving style. Go for a higher number i.e. “6 puck” rather than the 3 puck etc as the shock loads are horrendous on the lower numbered pucks, and break input shafts and pinion gears all the time. My scrap bin is full of them.
It might be helpful for people to leave some of their experiences with different clutches. To keep it neat (excuse the pun), state your engine, power figures, clutch type, driving style (street, aggressive street, drag, hill climb etc) and your experiences around it.
Hope this helps the community.