I was informed by a mechanic today that he installed LSD, Dinan, on an E90 2008/9 M3 and that LSD modification alone increased horsepower by 50, hence, approximately 464 horses after installation. He did not specify whether it was 3.45 or 3.62 which add 9.5% and 14.9% respectively. Irregardless, even though that's not a word, an increase of 50 horsepower from LSD mod sounds a bit exaggerated. Can someone respond with with an explanation, their experience with LSD mod, or a technical explanation/clarification? I'm not a track guy and have basic technical knowledge (I think). I would like to upgrade my LSD and my exhaust. Does that sound like reasonable for a guy that will not track his M3 buy wants a little better horse and torque improvement on the street. And last, if I upgrade the LSD do I need to change anything else regarding compatibility for the vehicle to handle the additional torque or horsepower?
Changing your final drive (diff) won't do anything to your horsepower rating. At least I have never heard of such a thing. BUT a final drive with a different ratio will change your torque numbers at the rear wheels. A higher numeric (lower ratio) final drive will increase your torque at the wheels and decrease your acceleration times. In other words the car is quicker to 60 mph. The down side of course is higher revs at highway speeds, a reduce top speed, and increased fuel consumption. This info is true whether the final drive is LSD or not.
So...approx how much top end/reduce speed would one lose by changing the LSD? And is there a "happy-medium"? Why would a person sacrifice the tradeoff unless he/she is tracking their vehicle or racing people in 1/4 mile runs? And last, is their anything I could do to off set the loss of reduced speed? If I changed the throttle bodies, upgraded intake and exhaust, Dinan software reprogram,what would be the result of those mods? Not that I plan on driving in the 140s but the vehicle accelerates so quickly that I can be at 100 mph in no time flat.
Your mechanic is mistaken. Gears get the power to the ground much quicker though and is worthy addition for performance. Fuel consumption? I lost about 1.5 mpg on average; BFD. Gears are the best bang for the buck for an E46 M3 that I have found.
If you daily drive the car, don't change your diff. All you'll get in return is worse fuel economy, and it's not like the M3 is good on gas to begin with. If you don't track or race your car in any way, personally I would say don't bother. I would say the Dinan flash would have the most effect, though you won't get such a significant increase (IMO) since you don't have a turbo or anything of that nature. There's only so much of an increase you can get from a Naturally Aspirated engine without going forced induction.
An LSD does NOT change HP An LSD does not change HP nor does gearing. An LSD provides better traction under acceleration by using both tires instead of one wheel spinning. Gearing changes torque to the wheels which can improve acceleration, but at an increase in engine RPM for any given vehcile speed and thus a reduction in mpg, higher noise at crusing speeds, etc. Gearing is always a trade-off. You can calculate the difference in torque by multiplying the gear ratios in the trans times the final drive ratio and taking the percentage difference.
Thanks everyone and I understand all comments/feedback. I felt it was far-fetched when he mentioned the increase and I knew that the LSD only increased the torque but needed confirmation. This mechanic has been in business for a while and deals primarily with BMWs. He is also a Dinan installation specialist. To AZ3579...I have both a 2010 M3 w/DCT and a 2006 E46 M3 with SMG. I'm selling the E46 as of today and it pains me that I can't keep both. That said, I'm inquiring about the 2010. Sounds as though changing the LSD would be nice to have. While I'm ok with sacrificing a mile or two mpg for the power since I'm not tracking nor plan on racing LSD may not be a worthy investment at this point. The 2010 tends to hesitate occasionally so I wanted to remedy the hesitation in addition to optimizing what I have. So I'll just stick with the basic bolt-ons and aesthetics (wheels & lowering) with the following for a balance of aesthetics and a little better performance, feel free to comment: - Throttle bodies (maybe) - Eismann or Supersprint Exhaust - Headers (if possible, maybe) - Cold Air Intake - Dinan Suspension Upgrade
I have a friend with an M3 that has a Powerchip. He is very happy with it and I think it's supposed to be around 440+ hp, a healthy increase over stock. You'll have to ask him though. Steve, feel free to chime in.
Very happy Powerchip camper here. One has to wonder if an Eisenmann Race Exhaust is far behind. Hmmmm...................
