I'm hoping to 2.5 swap my 2006 NC sometime, so I'm looking to do some upgrades this summer to make that better when it happens. I'm envisioning a mild-cam naturally aspirated 2.5L at this point. This is my summer daily driver, so I'd like to keep it nicely streetable while still making it as capable at autocross as I can. So far, I've swapped in a set of Bilstein B6 shocks and 58 White/58 Red GWR bumpstops, a Hotchkis front sway bar, and a Roastersport Street Single muffler. I'd like to work with those existing mods and add the following mods to prep for the 2.5L:
- Improve total exhaust system flow
- LSD
- Wider Tires
An LSD should also be relatively straight-forward. I'm leaning towards one of the Tomei options at this point since they are cheaper, and I don't plan on going bonkers with the 2.5L power. Again, does that seem reasonable? Would you recommend the 2-way or 1.5-way?
Tires get a bit more complicated. As I understand it, to fit the widest tires I can without flares (245), I need to lower the car some to improve camber to ~2 degrees. I'd like to stick with the B6 shocks if that's reasonable as they only have about 5k miles on them. To that end, I'm looking at lowering springs. The options I can find available today (unfortunately not all on GWR) are:
Progress Technology - 126 lb/in front 116 lbs/in rear - expect 1/2" drop
Racing Beat - 145 lbs/in front 112 lbs/in rear - expect 1/2" drop
Flyin' Miata - 300 in/lbs front 196 lbs/in rear - expect ~1" drop
H&R - 235 lbs/in front 155 lbs/in rear - expect ~1 1/3" drop
Eibach - 140 lbs/in front 70-120 lbs/in rear - expect ~1 1/2" drop
This leads me to several questions.
- Would you expect 1/2" drop on an 06 to be enough to get the requisite camber to fit a 245 tire?
- The rates on the FM springs seem very high. Would you expect these to work with B6s? I'm guessing they would be stiffer than I want for daily use...
- Would 1 1/2" of drop be too much on stock length B6 shocks?
- Which of these options would you recommend for my application (as much grip as possible for autocross while still being a great daily driver)?