ariascarlos1990 Posted March 13, 2012 Report Share Posted March 13, 2012 So I as most of you may know the rearend in my wagon is toast. I don't know what gearing is in it but, I have a lead on a complete 3.90 rearend and have a question before I buy it. I am eventually going to run a '81-'83 zx 5 speed with the 0.745 overdrive 5th gear I've calculated that transmission with my gearing and tire diameter and at 70mph the rpm's will be at 2,971. Ok so here's the question will this setup not be ideal for a l20b with a Weber?or will there no be enough power to make it freeway friendly? Quote Link to comment
Laecaon Posted March 13, 2012 Report Share Posted March 13, 2012 3.889 is the stock rear end for an auto goon. It is what I have. With the dogleg and 185/60/14 tires and l18 has no problem at cruising at 35-40. No bog on accelerating at 40-45. 3.7 is stock for a manual wagon. Quote Link to comment
ariascarlos1990 Posted March 13, 2012 Author Report Share Posted March 13, 2012 Oops for my gearing I actually meant the 3.90 rearend. Quote Link to comment
Uber Deaf One Posted March 13, 2012 Report Share Posted March 13, 2012 Cruising at 3k is perfectly healthy for an L series. Quote Link to comment
datzenmike Posted March 13, 2012 Report Share Posted March 13, 2012 So I as most of you may know the rearend in my wagon is toast. I don't know what gearing is in it but, I have a lead on a complete 3.90 rearend and have a question before I buy it. I am eventually going to run a '81-'83 zx 5 speed with the 0.745 overdrive 5th gear I've calculated that transmission with my gearing and tire diameter and at 70mph the rpm's will be at 2,971. Ok so here's the question will this setup not be ideal for a l20b with a Weber?or will there no be enough power to make it freeway friendly? 70 MPH with RPMs at 2971 with a 0.745 overdrive and a 3.90 diff you would have to have a tire with a diameter of roughly 23" 3.889 is the stock rear end for an auto goon. It is what I have. With the dogleg and 185/60/14 tires and l18 has no problem at cruising at 35-40. No bog on accelerating at 40-45. 3.7 is stock for a manual wagon. The dogleg has a 0.854 or 14.6% overdrive so a little easier for you than with the 0.745 or 25.5% overdrive in the zx. Cruising at 3k is perfectly healthy for an L series. That's about 200 RPM under it's peak torque so perfect. To accelerate you would down shift anyway but for level cruise that's good. Quote Link to comment
Laecaon Posted March 14, 2012 Report Share Posted March 14, 2012 The dogleg has a 0.854 or 14.6% overdrive so a little easier for you than with the 0.745 or 25.5% overdrive in the zx. I am aware, it was simply for reference. Like at 40 I can accelerate with no bog, so at 70 there shouldnt be for his configuration... Quote Link to comment
ariascarlos1990 Posted March 14, 2012 Author Report Share Posted March 14, 2012 Just bought the 3.90 rearend putting it in tomorrow. We'll see how it goes. Going to pick up my 5 speed this weekend also. Very excite! Quote Link to comment
ariascarlos1990 Posted March 15, 2012 Author Report Share Posted March 15, 2012 Oh ya just thought I'd say that my rearend had 3.90 gears in it. :lol: Quote Link to comment
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