Z4 3.0 Track car build

[Scooba_Steve]

Sounding like a good plan so far. The only thing I would suggest for coilovers vs shocks and springs - you will get what you pay for, that doesn't mean the cheaper coilies are rubbish, just that, IMHO, if you're not going to adjust or don't have set up knowledge then B12 might be a better option.

Depending on what the E46 brakes (or 325mm from the 3.0si?) cost you may not get good value for money - not much more resistant to fade. You may get good results from putting in brake cooling ducts, perhaps taking out the fogs?

I'm not sure how much better the E46 ARBs may be, I'm not sure what's available but I'd be looking for something lighter and potentially also adjustable.

Don't neglect the front suspension, put some new lower arms on and poly the brake reaction bushings.

Definitely get some new engine mounts. See if you can get the E46 front strut brace to fit, the one from turret to turret (completing the triangle).

 

[Steve84N]

The Z4M offset front lower rear bushes are well worth it, they add castor so dynamic camber rather than static but it made a noticeable improvement to mid-corner grip for me. Makes me wonder if I should get camber plates after all as the grip has come from more camber.

Only a tyre temperature gauge will tell you how much camber you need, it will be different for most cars and drivers and tracks come to that.

Either way it's important to consider the loads being applied to the top mounts, so if camber is to be increased spherical bearing top mounts may well be required.

Whilst a tyre temperature gauge would be enormously useful you can still feel with your hand which parts of the tyre are working. The fact I got more grip from more camber tells me more camber in my case was a good thing with no gauge required.
I'm talking about getting closer to 2 degrees of camber not 3 plus where stresses are genuinely worth considering.

 

[Artful-Bodger]

The Z4M offset front lower rear bushes are well worth it, they add castor so dynamic camber rather than static but it made a noticeable improvement to mid-corner grip for me. Makes me wonder if I should get camber plates after all as the grip has come from more camber.

Only a tyre temperature gauge will tell you how much camber you need, it will be different for most cars and drivers and tracks come to that.

Either way it's important to consider the loads being applied to the top mounts, so if camber is to be increased spherical bearing top mounts may well be required.

Whilst a tyre temperature gauge would be enormously useful you can still feel with your hand which parts of the tyre are working. The fact I got more grip from more camber tells me more camber in my case was a good thing with no gauge required.
I'm talking about getting closer to 2 degrees of camber not 3 plus where stresses are genuinely worth considering.

It's down to what the individual is comfortable with so you make your choices and live with the results, so if your happy with that approach that's ok.

If you want the best out of your chassis everything starts with the tyre, the whole suspension and chassis is working to load the tyre and the guy who dials the car into the tyres requirements will achieve the highest grip and handling.

Increasing the camber can overheat the inner edges of the tyre during periods of low roll such as long straights fast corners, reduce grip under braking, cause premature wear and reduce grip in other parts of the envelope, so whilst you can feel more grip in some aspects it's advisable to know what the tyre is doing, especially as its a in combination with tyre pressure.

Your looking for an average spread of temperature across the tyre, the inner will be hotter than the outer so a rough guide is the centre of the tyre should be the average of the inner and outer temps, you juggle this in competition dependant on the track but for a track day car if you can achieve this with a combination of pressure and camber you will get the best out of your tyres.

 

[Steve84N]

Agreed.

 

[oalloyd1]

This is excellent guys, cheers!

I'm tempted by the B12 but would really like some coilovers - I need to make the decision this week either way as I need to get the build underway as not too long til this years' Nurburgring trip.

just got back from picking up the new lightweight wheels that are going on for the 4 square set-up - Its going to be an expensive month

o

 

[oalloyd1]

So just bought this as it made such a difference to the shift quality of my E46 M3 - Here's hoping it'll do the same job here!

http://www.ebay.co.uk/itm/192098545555

o

 

[oalloyd1]

Hey all,

I'm about to buy the following - Can someone steer me to the best value place to get these from? Anyone got any special deals on right now?

Mfactory LSD fitted.

Coilover set that costs less than £650 but isn't totally rubbish

Uprated braided hoses and pads and race fluid at same time.

Uprated RTABS and any key other suspension components (Can't justify polybushing the whole car right now)

Cheers,

o

 

[oalloyd1]

UPDATE

So it;s had the hard top bolted in place and I must say I think it looks great. The car also felt noticeably stiffer to drive with no wobbles or shakes so it feels like a great base to work from. The colour is also growing on me more and more, especially as it's quite unusual.





Straight after these pictures were taken I got it on the ramp for a close inspection of underside, bushes, hoses etc and was stunned at what great shape its in - I've seen 3 year old cars with more corrosion than this underneath! It's going to get a Dinitrol treatment once the suspension / bush work is done to make sure it stays like that for decades to come.

Whilst I was there I did a high quality oil and filter change as that's always first port of call when getting a new car for me.

Onwards with getting the modified parts purchased and fitted! Any advice appreciated - I've done E36's and E46's before but not a 'Z

Cheers all,

o

 

[Fishy Dave]

In addition to the AD08R tyres recommended above I would also consider the Nankang NS2R as a possibly cheaper option again. A number of us use them with success on road and track.

 

[oalloyd1]

Cheers Dave that's exactly what I was thinking.

Am going to run a 17" square set-up (8.5J) - What tire size do you reckon is best considering i'll be dropping the car 30mm and need to avoid any scrubbage... I'd also like to fit some spacers but might that make the risk higher?

Thanks again,

o

 

[Steve84N]

Hardtops look so much better in the right colour.

Interesting how you can tell the difference in stiffness, so many people claim they can't feel a difference between the coupe and roadster but clearly it's noticeable if you felt it with just a hardtop.

 

[oalloyd1]

Yes its certainly noticeable! Less creaks and better steering

 

[NeilP]

Cheers Dave that's exactly what I was thinking.

Am going to run a 17" square set-up (8.5J) - What tire size do you reckon is best considering i'll be dropping the car 30mm and need to avoid any scrubbage... I'd also like to fit some spacers but might that make the risk higher?

Thanks again,

o

This thread is awesome! Love the colour!

Been doing something similar with my e85 - been happy with the bc racing coils (in budget for you as well)

I've had a small amount of rubbing with my prorace 1.2 17x9 running a 255 section ns2r tyre - but then again, the tyre does run a lot wider

 

[oalloyd1]

Cheers Neil! I'm really getting into this car

OK how much is yours lowered by? Does the rubbing cause an issue? Does it rub on the inside or outside? Would rolling the arches help? I'll be running 17x8.5 so would that be less risk since yours are 9J? Thank you!

o

 

[oalloyd1]

Hi Steve,

I'm looking for these lower bushes, have you got a link?

Cheers!

o

The Z4M offset front lower rear bushes are well worth it, they add castor so dynamic camber rather than static but it made a noticeable improvement to mid-corner grip for me. Makes me wonder if I should get camber plates after all as the grip has come from more camber.

 

[Steve84N]

https://www.powerflex.co.uk/road-se...+Wishbone+Rear+Bush,+Caster+Offset/11515.html

 

[Fishy Dave]

Worth talking to Gary Feakins Racing: http://www.garyfeakinsracing.co.uk/
He is building the 3 litre Z4 race cars and supplies lightweight hardtops, LSD, lightweight looms, ECU and maps etc. etc.

 

[oalloyd1]

Thanks Steve!

Dave, yep have been in touch though still waiting on their quote

o

 

[Anonymous]

Have you made any decisions about the coilovers you're going to buy? Im thinking about getting a set for my car and not sure what to go for.

 

[oalloyd1]

Hi all,

Yes LordO, have gone for the latest BC racing set-up - Have had a good experience on my E46 M3 with them and they come with good adjustable top mounts.

Have got all the bits together now with the exception of a couple of bushes and the coilovers yet to arrive so it'll all be going together later next week hopefully!

o