Hey all, recently picked up a 2008 e86 z4 3.0si as a fun weekend car and occasional track use. Been wanting to get into track for a long time and after a day at palmersport in August I finally bit the bullet and bought a car to build out for next season.
Looking for some advice for upgrades I plan to make. Some will go on over winter before getting out on track in spring, some after I get started - I don't want to entirely pre-prep the car because I want to experience the shortfalls I'm trying to remedy so I better understand what benefit they have for the car when they do go on. I feel this will make me a better driver and give me a stronger understanding of how cars perform on track.
Been digging through historic threads and have gotten some ideas already, but would be great to get some feedback, comparison, or suggestions I've not come across.
Suspension
So far it looks like popular options for mixed use on the e86 are:
Kw v3 - £2-2.3k
Bilstein b16 pss10 - £1.5-1.7k
Bc racing br series - approx 1k
Ohlins are likely to be out of budget unless heavily discounted for black friday.
Bc are most budget friendly but I don't want to end out swapping later to upgrade again, leaning toward kw or bilstein - any thoughts?
Brakes
I know less here, how are the si brakes on track? I know they got a bigger set than the 3.0i, and that cooling and pads are key.
Upgrade wise, to begin with I'm hoping to focus on cheaper upgrades, thinking:
Braided lines
EBC bluestuff track pads
Brake cooling ducts to replace the fog lights (already had these made).
Further down the line, I'd like to upgrade to floating calipers, 4 or 6 pot. I've heard 130i/135i bmw performance brakes with e46 m3 discs can fit, and there are some dedicated bbks out there, some using renault calipers, but really not sure what's best for my application, and most cost effective. I've also heard the 130/135 calipers have ceramic pistons which can crack under track temps.
Any tried and tested approaches, kits, or swaps from other models for brake upgrades? And when upgrading discs and calipers, is it best off doing all 4 corners? Seems like it's easier and cheaper to just upgrade the fronts, but concerned this might mess with brake bias?
Limited slip diff
Fairly certain i'll go with a Quaife helical ATB fitted at birds. Seems to have solid in the field feedback and birds are well regarded.
I know the wavetrack won't spin a wheel if it lifts, but from what I've heard more is made of this than is really an issue, and it's a bit of a gimmick. For the extra money, I suspect I'll notice little difference.
Aero
Lowest priority on my list, definitely wrll into next year, but I do currently have a fairly large gt wing on the car (came with it) seems like a cheap ebay special, looks ok, but is aluminium and the mounts look weak. Considering replacing this
Almost purely on looks, I'm also considering a fancywide rear diffuser.
I'd like a front splitter, again largely for looks but any performance gains are welcome. Have had trouble finding one I like.
For areo in general i don't like the maxton design stuff, AP and varis are nice but very expensive. Any suggestions are welcome.
--
Thanks for any advice you can give, or if I've missed anything. I know I don't need everything here to get out on track, but would love to slowly build it up into a street/track weapon - comfortable with the compromise dual use brings
Looking for some advice for upgrades I plan to make. Some will go on over winter before getting out on track in spring, some after I get started - I don't want to entirely pre-prep the car because I want to experience the shortfalls I'm trying to remedy so I better understand what benefit they have for the car when they do go on. I feel this will make me a better driver and give me a stronger understanding of how cars perform on track.
Been digging through historic threads and have gotten some ideas already, but would be great to get some feedback, comparison, or suggestions I've not come across.
Suspension
So far it looks like popular options for mixed use on the e86 are:
Kw v3 - £2-2.3k
Bilstein b16 pss10 - £1.5-1.7k
Bc racing br series - approx 1k
Ohlins are likely to be out of budget unless heavily discounted for black friday.
Bc are most budget friendly but I don't want to end out swapping later to upgrade again, leaning toward kw or bilstein - any thoughts?
Brakes
I know less here, how are the si brakes on track? I know they got a bigger set than the 3.0i, and that cooling and pads are key.
Upgrade wise, to begin with I'm hoping to focus on cheaper upgrades, thinking:
Braided lines
EBC bluestuff track pads
Brake cooling ducts to replace the fog lights (already had these made).
Further down the line, I'd like to upgrade to floating calipers, 4 or 6 pot. I've heard 130i/135i bmw performance brakes with e46 m3 discs can fit, and there are some dedicated bbks out there, some using renault calipers, but really not sure what's best for my application, and most cost effective. I've also heard the 130/135 calipers have ceramic pistons which can crack under track temps.
Any tried and tested approaches, kits, or swaps from other models for brake upgrades? And when upgrading discs and calipers, is it best off doing all 4 corners? Seems like it's easier and cheaper to just upgrade the fronts, but concerned this might mess with brake bias?
Limited slip diff
Fairly certain i'll go with a Quaife helical ATB fitted at birds. Seems to have solid in the field feedback and birds are well regarded.
I know the wavetrack won't spin a wheel if it lifts, but from what I've heard more is made of this than is really an issue, and it's a bit of a gimmick. For the extra money, I suspect I'll notice little difference.
Aero
Lowest priority on my list, definitely wrll into next year, but I do currently have a fairly large gt wing on the car (came with it) seems like a cheap ebay special, looks ok, but is aluminium and the mounts look weak. Considering replacing this
Almost purely on looks, I'm also considering a fancywide rear diffuser.
I'd like a front splitter, again largely for looks but any performance gains are welcome. Have had trouble finding one I like.
For areo in general i don't like the maxton design stuff, AP and varis are nice but very expensive. Any suggestions are welcome.
--
Thanks for any advice you can give, or if I've missed anything. I know I don't need everything here to get out on track, but would love to slowly build it up into a street/track weapon - comfortable with the compromise dual use brings