Damo's E86 for road and track - New upgrades incoming!

[damocell]

Well....I defo like to make things difficult for myself!

Trackday on the 14th (7 days away), unfortunately I heard from Tegiwa on Friday my coilovers have been delayed due to a typhoon! It's become apparent that my drivers front shock has given up the ghost and the passenger front isn't too far behind it. Not ideal for a trackday especially as I'm getting some weaving under extreme braking which I found out whilst bedding my new pads in. Decided to bite the bullet and buy 2 new front B8 Bilstein shocks yesterday, hopefully they will be delivered tomorrow. This means the car will be ready for the trackday and once I sell the B12 kit it'll come with one week old £460 dampers.

Decided to test all the suspension bolts to make sure they came undone nicely, they all did....except one! The front passenger pinch bolt snapped instantly. Quickly jumped on eBay and managed to source a hub with a bearing which feels/sounds in better condition then my current one about 30 minutes from me. Began stripping down the passenger suspension along with ordering new BMW bolts, nuts and 5 more wheel studs.





This is the better of the two front dampers



A few days ago, before the suspension fiasco, I got around to fitting my passenger side new calipers and front braided hoses.

Me and bolts don't mix well







Also flushed the whole system with RBF660. Thr old brake fluid was pretty dark and didn't look great



Also gave the sodding thing a clean! It'll be a new car by the time I've replaced everything

 

[damocell]

In other news, I've also managed to get some baseline performance figures.

Turns out the MAF housing I was sent for my homemade induction kit was the wrong diameter (70mm) and made the car slower. Whilst I wait for the replacement I've gone back to the stock filter/setup. So these figures are for a bone stock car on old Avon touring tyres.

Untitled by Damien Bower, on Flickr

Untitled by Damien Bower, on Flickr

Untitled by Damien Bower, on Flickr

All measurements taken using a RaceBox Mini, not bad for an 18 year old car.

Also, I've managed to find some new to the market brake ducts which are designed to fit the LCI front bumper. As far as I'm aware I'm the first person to receive them outside of the guy who created them. I'll post pics once they arrive.

 

[damocell]

Strap in, this is a long update. What a couple of weeks I've had with the Z4!

It all started 9 days before my first outing on the Z4 on track at Anglesey when Tegiwa messaged to say my coilovers wouldn't arrive in time to be fitted for the track day. I knew my Bilstein B8 front dampers were pretty shot with noew knocking like mad so decided to order 2 new front B8 dampers from Demon Tweeks at a cost of £468. The thinking was that no one will want to buy a B12 kit with ruined front dampers anyway so I might as well replace, enjoy the track day and sell on.

Started fitting the first damper with 6 days to go till on track and the pinch bolt snapped instantly!

Untitled by Damien Bower, on Flickr

Gave the arch a good clean to make up for having to strip it down

Untitled by Damien Bower, on Flickr

Untitled by Damien Bower, on Flickr

Managed to source another hub locally that had a good bearing, that meant i needed new studs too. The cost quickly went up to £550 especially with faster postage.

Untitled by Damien Bower, on Flickr

Untitled by Damien Bower, on Flickr

But it all looked good once the brand-new damper was installed

Untitled by Damien Bower, on Flickr

Untitled by Damien Bower, on Flickr

New studs install with the correct locktite

Untitled by Damien Bower, on Flickr

Untitled by Damien Bower, on Flickr

Decided to leave the drivers side till the next day.

Next morning......received a text from Tegiwa....my coilovers were on their way This takes us up to Thursday now when they arrive. T minus 4 days

Untitled by Damien Bower, on Flickr

Untitled by Damien Bower, on Flickr

Untitled by Damien Bower, on Flickr

Untitled by Damien Bower, on Flickr

Untitled by Damien Bower, on Flickr

This has always been planned to be a "budget" build but using well throughout components. My last car had £3200 KW Clubsport suspension with stiffer springs and a lot of other components thrown at it and whilst it was great I vowed this would be a more cost effective track car. I've also used BC and Bilstein before and was impressed with BC although their build quality isn't the best.

Coilovers in consideration were BC, ST, GAZ, HSD and Bilstein. I quickly ruled HSD and GAZ out as I've known people who've had problems with them. Bilstein were the most expensive, and I decided against spending so much. This left ST XTA, BC ER and Yellowspeed with 3 different options of spec.

The ST were ruled out due to their spring rates not being firm enough and the rear spring being progressive although bing KW their damping would probably have been the best. However, I didn't fancy the cost of having them revealed to match firmer springs as I'd quickly find them to be too soft.
I couldn't make my mind up between BC or Yellowspeed, both had a range of spring rates and models, then eBay sent me a code and I got these for the 25% off of the pretty much £1000 pricetag. Plus the 8kg front and 10 KG spring rate seemed about perfect along with the damping adjustment that changes compression and rebound in one click not just rebound as a lot of coilovers do.

Taking the out of the box, the quality feels great and they have a 2 year warranty. Fitting went to plan although you have to set the rear shock stroke which took a little while to get my head around and some calculations using calipers and some setting up.

Untitled by Damien Bower, on Flickr

Untitled by Damien Bower, on Flickr

I also got some rear shock tower plates from Six Shop but they don't fit as the holes just arent far enough apart. So they are going back.

Untitled by Damien Bower, on Flickr

Started driving the car and the rear was making quite a bit of noise over large pot holes and sharp bumps. Defo not all the time but was a little annoying. A little investigation revealed a very small bump stop and the solid top mount was indeed very solid. I adjusted the shock stroke a little and refitted the Meyle HD top mounts and cut down bump stops from the old suspension. Its perfect now.

Untitled by Damien Bower, on Flickr

Its now three days to go to the track day, I went and got my track tyres fitted, stock size Zestino Grdge 07RS. Never used the before. Weighed the wheels, the Style 32 rear wheels only weigh 9.2kg without tyres, happy days.

Then the car decided it didn't like something and lit the dash up. No DSC, TC or ABS. DSC and TC I can live without but the ABS was defo needed. A quick scan of ISTA revealed it needed a right rear sensor.

Untitled by Damien Bower, on Flickr

Had to buy from GSF as they were the only ones that could get one in time for another £80.

Sent the car for an alignment check with two days to go which revealed it wasn't too bad.

Untitled by Damien Bower, on Flickr

Untitled by Damien Bower, on Flickr

Managed to take a touch of camber off the passenger front and add some more negative to the drivers. Car tracks straight and true but the addition of semi slicks and camber has exacerbated the loose weaving feeling at speed above 70mph
Read up on a thread by Lee Joyce about the steering and knocked the wheel about 1cm anticlockwise which has made a massive difference, although now the steering wheel doesn't return as positively, I might need to redo it with a touch less.

After putting a post out on FB about brake ducts I managed to get hold of a set of new ducts designed to replace the LCI foglights.

Untitled by Damien Bower, on Flickr

Untitled by Damien Bower, on Flickr

Quality is great and they mount to the exact mounting points of the foglights. Installation was pretty easy. So far I've run the pipework to the backing plate and aimed it at the gap which is already there. Can't think of a better option for the LCI

Untitled by Damien Bower, on Flickr

Untitled by Damien Bower, on Flickr

Untitled by Damien Bower, on Flickr

Untitled by Damien Bower, on Flickr

This took me to Sunday with the track day being the next day, so I then gave the car a bath and hith the sack. Crazy week but the car was as ready as it could be.

Untitled by Damien Bower, on Flickr

Untitled by Damien Bower, on Flickr

Untitled by Damien Bower, on Flickr

 

[1536Z4]

new ducts designed to replace the LCI foglights.

Nice write up on the suspension . Can you provide a link for the ducts . How did the track day go ?

 

[damocell]

new ducts designed to replace the LCI foglights.

Nice write up on the suspension . Can you provide a link for the ducts . How did the track day go ?

Just about to

 

[damocell]

So onto the track day.

Early start at 5am and first time driving the car at motorway speed since playing with the steering...all I can say is that's it is fixed, but now the wheel is less likely to self return so i maybe need to take it back a few mm.

Arrived at Anglesey, put the car in the garage and went for the usual full English before sighting laps.

Untitled by Damien Bower, on Flickr

Untitled by Damien Bower, on Flickr

Car felt good on the sighting laps, so we went straight out on the GP circuit for a proper warm-up. 5 laps later back in the pits the tyres had ballooned so dropped the pressures to 33 front and 32 rear. Checked brake temps and couldn't quite believe the front temps, 250 degree discs but only 90 degree calipers! To give some context, my last track car an Astra J VXR with Brembo 4 pots would boil its fluid after 4 laps reaching temps of 350 degree discs and 350 degree calipers due to zero cooling! I know Anglesey isn't particularly hard on brakes but the delta between discs and calipers was impressive. Rears were much hotter but we'd left the stability on, once that was off they settled down.

We couldn't have asked for better weather, hardly a cloud in the sky and mid-teens on the temp. Looking back at my telemetry and videos we didn't exceed much over 100 degrees for coolant, but I'd love to know what temp the oil was at.

Some great lapping in the morning with a best of 1:47 on the international with some traffic. However, I'd started to notice the brake pedal getting a little longer after a session and taking a lap to go harder. Almost like the pads were glazing which knowing the temps we were hitting was impossible. Grip from the Zestino's was very impressive, regularly pulling 1.2g lateral peakig at 1.3 in some corners and holding up to the abrasive surface well. Car felt great, very very stable, almost too stable so I dialed up the rear dampers a little which helped rotation. The car still wants to under rather than oversteer though even trail braking induces a little understeer with the back resolutely planted

Untitled by Damien Bower, on Flickr

Untitled by Damien Bower, on Flickr

Untitled by Damien Bower, on Flickr

Untitled by Damien Bower, on Flickr

Went over and got talking to a fellow Z owner, To, who was on his first track day in his totally stock Z4 E85. Took him for a passenger lap in the afternoon for him to see what different suspension and brakes could do.

Untitled by Damien Bower, on Flickr

After lunch they opened the Coastal Circuit which I prefer. Again the car performed really well, I once again dialed the rear dampers up a bit, high-speed stability was great, very impressive. But the pedal was getting longer and longer...not confidence-inspiring at all. Then we noticed a cut in the driver's front probably from a kerb

Untitled by Damien Bower, on Flickr

But it wasn't through the tread so we cracked on regardless

Untitled by Damien Bower, on Flickr

Brake pedal was now quite long and as it was 4 o clock we decided to call it a day.

Untitled by Damien Bower, on Flickr

Untitled by Damien Bower, on Flickr

Untitled by Damien Bower, on Flickr

Untitled by Damien Bower, on Flickr

Still, I managed a 1:22.0 on the Coastal circuit which I'm over the moon with.

On the way back the brakes got worse, requiring three pumps of the pedal before any serious retardation occurred. It was fairly obvious the master cylinder was failing. I nursed it the 2.5 hour journey home and was happy to arrive. Straight on the laptop and a new master cylinder has been ordered along with more fluid

Couple of fast laps from the day

[youtube]a72de4mmpE8[/youtube]

The track day has given me some food for thought. The car was super stable, allowing me to push pretty hard and inspiring confidence, the coilovers were great dong exactly what I hoped they would given the spring rates.....but I'd prefer some adjustability, especially on the brakes to get the car turning. Next up is a plated LSD but I now can't decide on the spec as I don't want to induce entry understeer but want an aggressive lock on accel so I can steer from the rear. I've got some thinking to do.

Also, I think I'll be going to a 255 square setup to add more front-end grip which will hopefully bring the rear into play, then I'll start considering a stiffer rear ARB.

all in all a great first day without major incident and a good base to build on. Cracking cars on track these Z4's.

 

[1536Z4]

So onto the track day.

Great news on the suspension and the brake temps . Lots of induction sound from your intake set up Shame about the tyre cut and the brake master but excellent weather considering it was hammering down with rain here only 2 hours away . Photos and video

 

[damocell]

So onto the track day.

Great news on the suspension and the brake temps . Lots of induction sound from your intake set up Shame about the tyre cut and the brake master but excellent weather considering it was hammering down with rain here only 2 hours away . Photos and video

Thanks, funnily enough I was back on the stock airbox for the track day and after seeing how low the IAT's stayed I think I'll keep it stock. It does seem loud though and I've no idea why

 

[1536Z4]

back on the stock airbox for the track day

Maybe it is just a microphone sound thing . Still haven`t seen a link for the brake intakes

 

[damocell]

back on the stock airbox for the track day

Maybe it is just a microphone sound thing . Still haven`t seen a link for the brake intakes

Apologies, at the moment there is no link. I posted on the Facebook pages a few weeks ago asking about brake ducts for an LCI. A guy got in contact saying he'd made some for himself and would I like to try the second pair he'd made to test them with a view to him making them to sell.

Here is some more info:

462683274_10227413505705216_8751614436151861248_n by Damien Bower, on Flickr

Would you like me to try and get some contact details as I just contact him via Messenger?

 

[1536Z4]

Would you like me to try and get some contact details

Yes please

 

[damocell]

Would you like me to try and get some contact details

Yes please

Sorry, completely for got about this, email address for him is [email protected] his name is Mike

 

[damocell]

Since Anglesey, not a lot has happened with the Z4

I bought a Febi master cylinder to replace the dead one on the car. That was a mistake. Since fitting it I've had to bleed the brakes every week, its obviously faulty. Now there is an ATE one in its place and all is good with the brakes again.

I did however manage to get a little evening track time at 3 Sisters which is local to me. The Z4 felt great on such a tight and twisty track, unfortunately I was still on my Febi MC so only managed three sessions. One thing I'm realising is that it is super stable with this suspension setup, I defo think I'll be moving to firmer rear springs soon.

Untitled by Damien Bower, on Flickr

[youtube]YITfmjZIFmA[/youtube]

Driving on track in the dark was great fun, picking a braking point and line is obviously a lot harder in the dark and more of a challenge, I loved it tbh.

I also bought a new seat

Untitled by Damien Bower, on Flickr

Surprisingly the stock electric heated seats only weigh 26kg so there won't be much more than about 25kg weight saving if I swap both out. I need to figure out a safe belt solution too as they are quite tight and getting te seat belt clip through the harness slot is proving difficult.

The thing I'm most excited about though, is that I've ordered my LSD. I bought a ZF plated diff for my M3 last year but didn't get around to fitting it. My diff builder has been able to build me a ZF plated diff with 6 plates and 30:60 ramp angles which should give about 65% lock on accel and 25% lock on decel, exactly what I was looking for. Not only that but they are supplying it ready to bolt onto the car in a Z4 diff case with 3.46 FD. Cannot wait to fit it now. Got to wait a few weeks whilst they build it but happy days.

Hopefully going to get one more track day in before Xmas in December so should be another update soon

 

[1536Z4]

Sorry, completely for got about this, email address for him is [email protected] his name is Mike

Cheers Good to see the build progressing .

 

[Gwest44]

Looking good Damien you've clearly made some impressive progress with the coupe

I was out in my new aquisition today and went past your parent's old house on Ladybower.

 

[3002 tii]

I also bought a new seat

Untitled by Damien Bower, on Flickr

Surprisingly the stock electric heated seats only weigh 26kg so there won't be much more than about 25kg weight saving if I swap both out. I need to figure out a safe belt solution too as they are quite tight and getting te seat belt clip through the harness slot is proving difficult.

Re factory belts really have 2 options. First is to use an extender but not ideal since you’re changing the geometry and relying a non-OEM product does its job when you need it the most.

Second option is to swap out the factory receptacle from another model that’s either shorter or less rigid, which should create more ‘room’ when you snake the belt clip through the side hole.

Neither are perfect but they’re better than running the lap belt over the bolster, which is a safety risk. I run harnesses on track but went with option 2 and have extenders as backup in case I’m in hurry.

 

[damocell]

Looking good Damien you've clearly made some impressive progress with the coupe

I was out in my new aquisition today and went past your parent's old house on Ladybower.

20241120_122530.jpg

Sorry bud, only just seen this.

Z4M looks lovely bud!

 

[damocell]

Not much of an update but loads of stuff is about to happen!

Haven't really covered many miles but did try to do a trackday at Donington in December.....it didn't go well

Untitled by Damien Bower, on Flickr

A week before the trackday i changed my master cylinder again for an ATE one. The morning of the trackday, in the pits we did a full brake bleed using ISTA and went out on track. Once again by lap 4 I had spongy brakes and a long pedal, back in the pits and there was air in the front brakes

The weird thing is, I'm not losing any fluid, just adding air. We tried to solve the problem but couldn't and left the track at 11am feeling pretty dejected. The Mazda race team we were sharing a pit with suggested tieing the fluid reservoir down with cable ties which we did as we left the circuit. They also mentioned pad knock off so I'll replace the wheel bearing as a preventative measure.

Untitled by Damien Bower, on Flickr

Driving home, this has actually helped, however, I still need a courtesy brake before then releasing the pedal and pressing again for full braking ability.

Having found this thread, I've decided to try replacing the ABS/DSC pump

https://z4-forum.com/forum/viewtopic.php?t=135378&start=15

As E86 ones are mega expensive I'v sourced one from........a Volvo for the princely sum of £18! Looks the same, hopefully should work, if not I'll spend some more money.

Since then, I've changed the front wheel bearings

Untitled by Damien Bower, on Flickr

Bought some new brakes to go with 340mm discs

Untitled by Damien Bower, on Flickr

Found out the new calipers look great on, but don't fit behind my wheels

Untitled by Damien Bower, on Flickr

Bought a bigger knob

Untitled by Damien Bower, on Flickr

and this super special item should be delivered very soon

Untitled by Damien Bower, on Flickr

It's an upgraded 1.5 way ZF plated diff with 6 clutches and approx 58% accel and 23% decel locking, should mean i can rotate the car on power and brake harder into corners. Its also been fitted with a 3.73 final drive for a bit more torque to the wheels and pep out of some corners.

Untitled by Damien Bower, on Flickr

Also fitted a new starter motor as another car I had with an N53 needed to borrow the Z4's to check it's own had failed

Untitled by Damien Bower, on Flickr

Whilst doing this I also changed the PCV thing as it was clearly not doing its job correctly

Untitled by Damien Bower, on Flickr

So......with 2 weeks and 4 days to go till the first trackday of 2025 at Bedford....which is notoriously hard on brakes. I need to:

Sort my braking issue, change my ABS pump and bleed
Fit my LSD
Change another wheel bearing
Refit my rear shocks to make sure the damper length is correct

So not much to sort!

 

[axelleveau]

Bought some new brakes to go with 340mm discs

Untitled by Damien Bower, on Flickr

Found out the new calipers look great on, but don't fit behind my wheels

Untitled by Damien Bower, on Flickr

Hi Damo, great summary and pretty cool things planned. I got a few questions about your attemp at upgrading the front brakes:
- Are you planning on using F series 340mm discs?
- I guess on your picture you put the caliper on top of your original 325mm disc? How does it fit in there? Is it centred between the pads or off towards the front of the caliper?

Reason I am asling is that I am worried the Fseries discs have too much height and will not fit BUT if the caliper sits different than the stock one on the stock disc then there is a chance to use other discs with a height between stock and F series by tapping into Land Rover stuff with or without some spacing of the wheel bearing.

 

[damocell]

Hi Damo, great summary and pretty cool things planned. I got a few questions about your attemp at upgrading the front brakes:
- Are you planning on using F series 340mm discs?
- I guess on your picture you put the caliper on top of your original 325mm disc? How does it fit in there? Is it centred between the pads or off towards the front of the caliper?

Reason I am asling is that I am worried the Fseries discs have too much height and will not fit BUT if the caliper sits different than the stock one on the stock disc then there is a chance to use other discs with a height between stock and F series by tapping into Land Rover stuff with or without some spacing of the wheel bearing.

Thanks

You are correct, that was bolted on with my 325mm disc just for the photo.

The F series discs won't fit as far as I know. The easiest and most cost effective option is to use 340mm discs from a VW T5/6 Transporter. With their centre bore enlarged they bolt straight on and only need a 1.5mm washer to spacer the caliper further out. Pad sweep is perfect and the fit looks excellent. As a plus, discs are cheap too. Even performance options come out at about £225-£250 per pair with OEM ones approx. £120 a pair

Only downside I can see is that all the T5/6 discs are pillar vaned and not curved for max cooling but the disc is very thick so will help with heat dissipation.

The extra weight of the discs is offset by the reduction in weight of the caliper too so it looks like the total weight will be very similar.

Full info can be found here:

[youtube]rr7IKTdEG6g[/youtube]