We are headed to Watkins Glen in April for some racing. The car is a 86 325e with a 3.5 b34/m30 motor(roughly 200hp and good TQ #'s). We have been using a 3.73 LSD gear ratio for the last many years. At VIR we noticed on the straights we don't rev out and can only hit about 121mph - need a lower gear to get up to speed faster. So, we ran out and got a used 4.10 LSD but now we think that might be too low. If we do the math:
Our Transmission gear ratio’s
1-3.83
2-2.20
3-1.40
4-1.00
5- .81
Current 3.73 ratio
RPM MPH
5000 113
5500 124
6000 136
3.91 ratio
RPM MPH
5000 108
5500 119
6000 130
4.10 ratio
RPM MPH
5000 103
5500 113
6000 124
We have never run WGI before but watching video's it's a very fast track. It seem like a 4.10 might be too much. 3.91 seems like a better choice. Looking for some expert opinions out there. We have started the search for a good used 3.91 in case that's the direction we need to go.
Thanks
Our Transmission gear ratio’s
1-3.83
2-2.20
3-1.40
4-1.00
5- .81
Current 3.73 ratio
RPM MPH
5000 113
5500 124
6000 136
3.91 ratio
RPM MPH
5000 108
5500 119
6000 130
4.10 ratio
RPM MPH
5000 103
5500 113
6000 124
We have never run WGI before but watching video's it's a very fast track. It seem like a 4.10 might be too much. 3.91 seems like a better choice. Looking for some expert opinions out there. We have started the search for a good used 3.91 in case that's the direction we need to go.
Thanks
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