I've seen this discussed in the past, and I've seen GT-Tuning's (UK Co.) solutions, but its been a while and I wonder if someone has any new intel.

Has anyone designed or found for sale, any tensioner modifications that will (1) increase the wrap around the 19% pulley; or (2) increase tension on the belt?

Belt slip is a drag... check that... if it were a drag, it wouldn't slip.

I'm of a mind to fix a bar to my tensioner to prevent it from slamming into the anything important should I have a belt snap. Also considering some way of shimming 1/4" to 1/2" under the tensioner spring to increase belt pressure.

Appreciate anyone's insights.
Ciao!

 

Its easy to space the spring with a large washer, but it wont do anything.

 

Do tell, X! Have you attempted or witnessed a spring shim? Why didn't it work? I'd be very interested.

If I do attempt to shim the spring, it would be with something much thicker than a washer.
Once the belt is streched, the spring is expanded beyond its normal factory position, and that means less tension on the belt. Adding a shim, I believe, would bring spring pressure back up to, or even above, the tensioning force present in a factory configuration.

 

Bluemini, The way I see it is the stock spring has plenty of stroke "doesnt need to be any longer" It has heaps of spare compression left even with a 19%, and a spacer wont put any more pressure on the belt as the spring is constant wound and not a progressive wound spring,

Therefore compressing the spring more with a spacer is just that compressing the spring more, not increasing the pressure.

Correct me if I'm wrong but thats how I see it

By the way I am sending you a PM.

 

for a coil spring, F=kx. the force is linearly related to the compression. if the stock compression gave 40lbs and compressed the spring 3/4", k would be 53lbs/in. if you then put in a smaller pulley, same belt, x would change to say 1/2" and F would be 26.5 lbs. More simply put, 1/3 the compression would give 1/3 the force.

 

So take your pick, spacer or shorter belt.

 

From somehwere deep within the recesses of my mind, I thought spring force was proportional to its compressed length. Thx for confirmation JLM. BTW... if memory serves, you were working on something. Were you successful in your redesign?

I also read a great thread on the pros and cons of running short and long (or streched) belts with the 19%. As I recall, it boiled down to two things.

A short belt allows the tension spring to apply more force to the belt and thereby to the pulley. Explains why a new fresh belt always gets me rising boost to redline.

A longer belt, or streched belt, wraps the pulley more, however, tension force is reduced on the belt and thereby the pulley causing belt slip. What I start seeing after about 3 months on a belt-- boost tops out at about 5500-6000rpm.

What I'm guessing at and wish to observe, real world, is to put more spring tention on the belt and pulley, while taking advantage of more belt wrap. The advantages of both situations.

I tried washers, but there isn't any way to get them on the tensioner without removing the spring. I'm going to attempt is use a "split collar" of about 1/2" thickness and see where that gets me.