Saturday I got a chance to see what gains could be had by replacing my stock 2.93:1 open differential with a 3.25:1 lsd in a few run-of-the mill acceleration tests. First, here are a list of my mods:
1986 325e
-Turner Motorsports Chip
-Turner Motorsports 8mm Plug Wires
-Z3 1.9 short shift kit
-Clutch Stop
-Blueblocker sunglasses
The first set of tests involved my car with the stock 2.93:1 open differential. (Note: All tests were done with the driver and two passengers in the car (approx 325 lbs), along with 85-90ºF weather). Here were the results:
0-50mph--------------------------------7.4 seconds
30-50mph (2nd gear)--------------------4.5 seconds
RPM's at 60mph in 5th-------------------~1800
The second test was performed later that day (in approximately the same weather) and involved my just-installed 3.25:1 lsd. Here were the results:
0-50mph---------------------------------7.1 seconds
30-50mph (2nd gear)---------------------4.2 seconds
RPM's at 60mph in 5th--------------------2100
" " 70mph in 5th--------------------2500
" " 80mph in 5th--------------------2900
As a comparison my friend's 325i with TMS chip and Ireland exhaust (incredible sounding!!) ran a 3.5 second 0-50mph on a stock differential (perfect for 2nd gear). We also ran a few 0-50 tests in his car and wound up with roughly the same times I was achieving. I don't take much comfort in the 0-50 tests as there are several variables that have a huge impact on the times achieved.
Upgrading from a stock 2.93 to 3.25 lsd is probably the best mod I've done thus far (not counting the TMS chip), especially when you consider what it does for your cornering capabilities. I was consistently getting power oversteer as soon as I touched the gas while cornering, but now I can practically plant my foot and the car just sucks to the road and launches out of the corner. It's a FANTASTIC feeling. Also, 2nd gear pulls much harder now and the bog between 2nd and 3rd gear is completely gone. In fact, 3rd gear feels like 2nd now and 4th feels like 3rd! I've been driving around town at 35mph in 4th gear and easily overtaking people!
I am curious to see what impact the extra weight and high temperatures takes on the #'s achieved. If you have a similarly modded car I would greatly appreciate you're #'s so we can compare data.
Hope this answered some questions for you eta owners out there...
-Max
Special thanks to my lovely girlfriend for recording all the data and Knuckles for helping me install the new diff.
1986 325e
-Turner Motorsports Chip
-Turner Motorsports 8mm Plug Wires
-Z3 1.9 short shift kit
-Clutch Stop
-Blueblocker sunglasses
The first set of tests involved my car with the stock 2.93:1 open differential. (Note: All tests were done with the driver and two passengers in the car (approx 325 lbs), along with 85-90ºF weather). Here were the results:
0-50mph--------------------------------7.4 seconds
30-50mph (2nd gear)--------------------4.5 seconds
RPM's at 60mph in 5th-------------------~1800
The second test was performed later that day (in approximately the same weather) and involved my just-installed 3.25:1 lsd. Here were the results:
0-50mph---------------------------------7.1 seconds
30-50mph (2nd gear)---------------------4.2 seconds
RPM's at 60mph in 5th--------------------2100
" " 70mph in 5th--------------------2500
" " 80mph in 5th--------------------2900
As a comparison my friend's 325i with TMS chip and Ireland exhaust (incredible sounding!!) ran a 3.5 second 0-50mph on a stock differential (perfect for 2nd gear). We also ran a few 0-50 tests in his car and wound up with roughly the same times I was achieving. I don't take much comfort in the 0-50 tests as there are several variables that have a huge impact on the times achieved.
Upgrading from a stock 2.93 to 3.25 lsd is probably the best mod I've done thus far (not counting the TMS chip), especially when you consider what it does for your cornering capabilities. I was consistently getting power oversteer as soon as I touched the gas while cornering, but now I can practically plant my foot and the car just sucks to the road and launches out of the corner. It's a FANTASTIC feeling. Also, 2nd gear pulls much harder now and the bog between 2nd and 3rd gear is completely gone. In fact, 3rd gear feels like 2nd now and 4th feels like 3rd! I've been driving around town at 35mph in 4th gear and easily overtaking people!
I am curious to see what impact the extra weight and high temperatures takes on the #'s achieved. If you have a similarly modded car I would greatly appreciate you're #'s so we can compare data.
Hope this answered some questions for you eta owners out there...
-Max
Special thanks to my lovely girlfriend for recording all the data and Knuckles for helping me install the new diff.
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