traction vs. weight

I now have 245/50r16s on chrome stock wheels all around on 02z28. Looking to upgrade to 17x9.5 w/ 275/40r17s on front, 17x11 w/ 315/35r17s in rear. After reading the sticky, it looks like that will be adding about 15lbs per wheel(average). I've got full bolt ons and will be adding h/c later. Probably will get the new wheels when I get the h/c. Want to be pushing about 420 rw ponies. Will the added weight be worth it in traction improvements? This is a daily driver, so I'm not interested in drag radials. I need wet and dry traction.

I don't think you'll see that much added weight. Brent's data collected in the FAQ indicates the stock wheels/tires are in the range of 45-48#. You would be adding about 5# for each front wheel, and 7-10# for each rear. The traction gains on my "bolt-on" setup going from 245/50-16 to 275/40-17 were huge. I can't really comment on the 315's because now that I run those, I use the BFG Drag Radials, that you aren't going to be using.

If you are going after 420 rwhp you should look into keeping a set of DRs on the side to play with or you'll just be wasting your power. Grabbing a set of 255 50 R16 M/T DRs on stock 16x8s will go along way when you want to have some fun...They are lighter and will out hook 275 and 315 17 DRs. I once ran 275s on 17x9" and 315s on 17x11 and saw no improvement...just more weight...

--Alan

another thing to consider with changing to the 17s is that there will be less sidewall.
less sidewall means less ability to flex when put under load (launching) which can negatively affect traction. will this be noticable on a street car...probably not. but it's something to think about.

on the flip side, smaller sidewall can make the tire more responsive to cornering input.

i will have to agree with the idea of having a set of DRs for play time. i couldn't beleive the traction difference going from 245 street tires (even though they were very sticky) to 315 DRs (and the drs were nearly worn out).

but since i'm living in south florida, havn't been to the track in 4 yrs, and have the car set up for handling more than launching...i'm gonna be moving to some good street tires soon.