Topic: 12hp pully set up

[bimmerbaz]

Hi There,

I would like to know what ratios you guys are running . I have a 5.5 inch on the motor amd a 6 inch on the jack shaft .The input shaft on the trans has a 3 inch pully on it giving me a ratio of 1 to 1.8.
When in 4th grear i have a ratio of 11 to 1 and in 5th gear it is 9 to 1.
Any suggestions for pully sizes to get best performance from motor it seems to not have a lot of power with this gearing.
cheers

[mowdaddy30]

what size motor?

[John692]

what size motor?

He has a 12 hp 28ci Briggs

[mightymowe]

The size of the track will make a difference on what gear you need.How does your speed compare to the other guys?Do some track testing,maybe you only need a slightly larger pully on the engine.A lot of the time I am geared for less top speed than some of the other guys,but I get them with the acceleration in the corners and down the straights.By the time they are up to speed where they can catch me I am in the next corner.A lot of the guys on here set them up with a 6:1 ratio in third gear,or which ever gear is 1:1 in the gear box.

[bimmerbaz]

thanks for that. I will try to aim for a 6 to 1 ratio . That 6 to 1 should be engine relative to wheel speed and not input shaft speed right? Should the trans have a 1 to 1 ratio in one of the gears ? ie 1 turn input to 1 turn output?
cheers