replace belts with chains?

[NiHaoMike]

What efficiency gains could be obtained by replacing the alternator/water pump/power steering belt with a chain? (Both from the reduced friction and by changing the gear ratios.)

With the proper selection of chain, it should be trivial to replace the alternator with a motor/generator and add some additional batteries and control electronics to make a hybrid.

[trebuchet03]

Ignoring the custom setup you described (as we're changing multiple variables)... Belts versus Chains, selection...

Chains have 0 elasticity - this is particularly useful in a jam (say a component seizes or provides too much resistance). In that sort of condition, a belt will slip (and make a terrible noise), a chain will break and throw.

Belts are typically made of some form of rubber, plastic, composite, etc. - which have nice damping properties - they will create less noise at higher rpm....

Chains require maintenance when exposed to the elements - less so in a sealed/oiled environment.

A properly designed gear and chain setup with proper lubrication will last for a freaking long time without maintenance (Example is the Saturn DOHC motors in the S series' timing chain - as long as it didn't run out of oil, it would last longer than the car)

Belts are super cheap and fairly easy to replace and tension.

Chains do not tolerate misalignment - belts have a high tolerance and some can self align with the proper pulley (belts always look for a high spot to ride).

Modern belts have a fairly high power transmission efficiency (mid 90's% and up).
Modern chain is in the mid-high 90's% too (bike chain efficiency: Headlines@Hopkins: Johns Hopkins University News Releases) but, they might be at tensioned fairly tight.

Switching from belt to chain probably won't yield any easily measurable gain in drive train efficiency.



I won't argue that one is necessarily safer than the other as a friend of mine lost part of his finger due to a belt related accident.

[Ryland]

Install a cog belt and you come out almost as efficient as a chain because of the lighter weight, they don't need lube and are quite.

[theunchosen]

The only other advantage of chains is weather. In the cold belts are far more likely to snap and cause serious issues for you. Chains are pretty resistant to that. . .but they aren't very resistant to rust. Belts don't much care about that four letter demon.

So take your pick. I agree not likely to see gains from chain switch over. Never have to change it. . .but if it breaks you're in trouble because how many autozones carry your chain?

[NeilBlanchard]

Hi,

A chain would require that everything be more perfectly aligned. Plus, changing the tensioner over may be a very tough thing to do -- don't most chain systems have the long curved "teflon" tensioner; while belts have a spring-loaded pulley? How would you securely anchor the tensioning hardware to the block? As someone already mentioned, chains require lubrication.

What are you trying to accomplish, again?

[Vwbeamer]

glad to see you thinking, but serpentine belts are just about the most efficient way to go.

I can't see how a chain would save much over a serpentine belt. there is a small savings switching from a v belt.

[Frank Lee]

I have long thought that a rubber coupling right off the crank snout would be the way to go... for one or two accessories that is.

[Bicycle Bob]

The old "silent chain" as used on camshaft drives can be 98% efficient. That might save 2 or 3% over a belt drive or roller chain. If you think custom hardware is worth it for that, maybe you want to go to a flat steel belt, which can hit 99%.

[wagonman76]

I looked this up once because I considered running a second distributor off an engine with a chain once, for some custom project. I checked my chain engineering book and it would have been going way too fast unless it had an oil bath lube. Which made the simplicity of a chain more complex than it would have been worth. I would have needed a timing belt and pulleys instead.

[NeilBlanchard]

Nothing has zero elasticity, period.

Cam shafts have torsional flexing, engine blocks distort, etc., etc.