fastsc92
Registered User
Ok i just got back from FFW at epping, NH. I live 30 min away so its a short drive. Anyways...i took the chance to get on the dyno there to make 3 pulls with a wideband 02 sensor. This dyno is a new style which doesn't use any drums. It is basically two boxes that bolt dirrectly to your rear wheels and the car rests right on them. They claim is the most accurate because there is no slipping. Anyways...they ask you what rear end ratio you have and what rpm you want to stop at. I told the guy 5500 to shut it down. The first pull he made, the rpm's were getting up there and it hit the rev limiter and he shut it right down. The dyno was supposed to tell him to shut it down at 5500. The car is run in 4th gear which is a 1:1 ratio. BUt, the machine said it was only at 5235rpms. For some reason the final drive in 4th gear is not 1:1. He asked me 3 times if i told him the correct rear end ratio, which is 3.27. I installed the gears myself and they are indeed 3.27's....the first thing when i opened the box was to count the teeth and divide and it came to 3.272727272727272727. The rear end ratio is correct..so something must be wrong with the tranny. He ended up tricking the computer and had to tell it that it had a 3.89 rear end ratio...which is bogus. I just rebuilt this tranny and there is no way that it could go together wrong. all the other gears are correct and shift smooth and fine. Why isn't 4th gear 1:1???? When i figured it out....the 4th gear is acttually 1.2 : 1. Why is this happening and how can i fix it? I am 100% sure that the rear end ratio is 3.27. Help me please. this also seemed strange because at the track...i am in 4th gear for almost half the track and pass the lights at 5100. Does anyone else have this problem with 3.27's in a speed???