E89 Z4 Track-ready Sleeper Build
- Thread starter Asbjorn
- Start date
Custom "sleeper" dampers installed!
Today we finished the installation of my new made-to-spec adjustable dampers. They took one month to produce and one day to install.
Before: Koni FSD, stock springs front, eibach pro-kit springs rear
After: Custom-dampers, exactly the same springs.
Super happy with the result. Before the front was much lower than the rear due to running max'ed out front camber. Now the front is still 5mm lower than the rear, but visually the car is much more balanced. There is much less scraping and much less "the tires might dent my hood"-anxiety. And most importantly. Much more sleeper!
And I know what you are going to ask. Do those blue stickers on the adjuster knobs come off, to make the dampers look even more OEM? Yes they do. Absolutely they do.
So basically the front damper has a longer housing in order to raise the front of the car. The piston has the same length, because it was designed to work with the stock spring.
The rear dampers were designed with a shorter piston compared to the KONIs in order to match the Eibach pro-kit springs, and align the rear suspension with the rear damper curve. The KONIs were made for stock rear springs. This also means there is now less suspension travel available at the rear compared to the front. This should help keep the shorter Eibach spring better in place. I have had one of the rear springs shift a bit on one occasion with the KONIs.
The new dampers also offer much more force compared to the KONI FSDs which were becoming quite comfortable. I had the rear dampers made with higher damper force compared to the front in order to match the stiffer Eibach springs, and accommodate for the power, track application and weight distribution of the car. (ie I wanted less understeer, more oversteer).
Below are the damper compression/rebound curves as provided by the factory (stiffest setting).
(Rear, 1338N, -843N @0.314m/s)
(Front, 938N, -605N @0.314m/s)
Both dampers are adjustable in 10 steps. The softest setting is already stiffer than the KONI FSDs. There is less weight transfer in all directions, and I can run a softer sway bar setting without loosing steering responsiveness. When I turn up the stiffness the car really gets on its toes and wants to play. Im pretty amazed how much work dampers are able to do. Can't wait to try them out on track.
Oh and today we also swapped in a #4 nozzle as recommended by you @F87Source as the #5 375cc nozzle was a bit oversized for WI.
Today we finished the installation of my new made-to-spec adjustable dampers. They took one month to produce and one day to install.
Before: Koni FSD, stock springs front, eibach pro-kit springs rear
After: Custom-dampers, exactly the same springs.
Super happy with the result. Before the front was much lower than the rear due to running max'ed out front camber. Now the front is still 5mm lower than the rear, but visually the car is much more balanced. There is much less scraping and much less "the tires might dent my hood"-anxiety. And most importantly. Much more sleeper!
And I know what you are going to ask. Do those blue stickers on the adjuster knobs come off, to make the dampers look even more OEM? Yes they do. Absolutely they do.
So basically the front damper has a longer housing in order to raise the front of the car. The piston has the same length, because it was designed to work with the stock spring.
The rear dampers were designed with a shorter piston compared to the KONIs in order to match the Eibach pro-kit springs, and align the rear suspension with the rear damper curve. The KONIs were made for stock rear springs. This also means there is now less suspension travel available at the rear compared to the front. This should help keep the shorter Eibach spring better in place. I have had one of the rear springs shift a bit on one occasion with the KONIs.
The new dampers also offer much more force compared to the KONI FSDs which were becoming quite comfortable. I had the rear dampers made with higher damper force compared to the front in order to match the stiffer Eibach springs, and accommodate for the power, track application and weight distribution of the car. (ie I wanted less understeer, more oversteer).
Below are the damper compression/rebound curves as provided by the factory (stiffest setting).
(Rear, 1338N, -843N @0.314m/s)
(Front, 938N, -605N @0.314m/s)
Both dampers are adjustable in 10 steps. The softest setting is already stiffer than the KONI FSDs. There is less weight transfer in all directions, and I can run a softer sway bar setting without loosing steering responsiveness. When I turn up the stiffness the car really gets on its toes and wants to play. Im pretty amazed how much work dampers are able to do. Can't wait to try them out on track.
Oh and today we also swapped in a #4 nozzle as recommended by you @F87Source as the #5 375cc nozzle was a bit oversized for WI.
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Decided two sets of BMW 293 wheels wasn't enough and ordered a third custom set in 4x 18in 9.5J ET35 forged. I wanted to go 10J square, but felt it was too risky up front.
Last year, although I did well in the rain, I was not satisfied with my tire setup for dry time attack. I was using a set of super cheap and heavy cast 9J et30 wheels in combination with used slicks in 245 or 250 sizes. Most of my competition was running new slicks in 265 or even 285 sizes.
This year my first time attack will be in June at an event where they only allow semi-slicks. Due to the limited tire options in China, it is pretty well known that Hankook z214 is the fastest semi-slick you can choose. However most of my competition will most likely show up with cup2 or trofeo r. I would also say that the track layout favors cars with good power and braking rather than those who are mainly setup for cornering.
In below picture z214 is on the right, ventus td is in the middle and rs4 is on the left. I am thinking about getting the TDs in 265 or 285 medium compound because then I can drive them to and from the track. z214 is only sold in 245 or 275 medium compound and cannot really be driven to and from the track I think. If anyone has any experience with these, please let me know.
As for power it is going to be hot and humid here in June. The competition is mainly M2-M4s, many tuned.
We added an extra 60cc nozzle to spray at the FMIC and lower radiator area behind it. I dont think it will help much, but looking forward to see what kind of temps the car will reach during the competition. I am also thinking to just go with the 16psi tune instead of the 18psi tune to keep timing corrections at a minimum. Might give better power in the end.
As I mentioned over in the accusump thread, we also replaced the rod bearings (which actually looked fine at 150.000km), and removed the lower part of the baffle wall in the oil sump. Since I have never seen any problems with oil pressure dropping during acceleration, even on stock cars, there wasn't really any reason for the wall to be there, even if it had a one-way door.
Finally we also added an oil dip stick. Should have done that years ago.
Last year, although I did well in the rain, I was not satisfied with my tire setup for dry time attack. I was using a set of super cheap and heavy cast 9J et30 wheels in combination with used slicks in 245 or 250 sizes. Most of my competition was running new slicks in 265 or even 285 sizes.
This year my first time attack will be in June at an event where they only allow semi-slicks. Due to the limited tire options in China, it is pretty well known that Hankook z214 is the fastest semi-slick you can choose. However most of my competition will most likely show up with cup2 or trofeo r. I would also say that the track layout favors cars with good power and braking rather than those who are mainly setup for cornering.
In below picture z214 is on the right, ventus td is in the middle and rs4 is on the left. I am thinking about getting the TDs in 265 or 285 medium compound because then I can drive them to and from the track. z214 is only sold in 245 or 275 medium compound and cannot really be driven to and from the track I think. If anyone has any experience with these, please let me know.
As for power it is going to be hot and humid here in June. The competition is mainly M2-M4s, many tuned.
We added an extra 60cc nozzle to spray at the FMIC and lower radiator area behind it. I dont think it will help much, but looking forward to see what kind of temps the car will reach during the competition. I am also thinking to just go with the 16psi tune instead of the 18psi tune to keep timing corrections at a minimum. Might give better power in the end.
As I mentioned over in the accusump thread, we also replaced the rod bearings (which actually looked fine at 150.000km), and removed the lower part of the baffle wall in the oil sump. Since I have never seen any problems with oil pressure dropping during acceleration, even on stock cars, there wasn't really any reason for the wall to be there, even if it had a one-way door.
Finally we also added an oil dip stick. Should have done that years ago.
If I were you I would put the water sprayer's in the middle because the water coming out of the nozzles are so finely atomized when you're driving the wind just forces the water to hit the side of the coolers and not reach any other part.
Funny you would say that. We actually had it in the middle, then moved it to the side.
Yeah, because there is so little water that comes out of these nozzles and it is so finely atomized the wind will just blow it onto the radiator the moment it leaves the nozzle and you really wont get much water distribution far over to the opposite side of mounting. That is why you should mount it in the middle because it will give it a better chance to spray more of the cooler.
But the best mounting position is to have the nozzle opening pointed directly at the cooler parallel with the direction of air flow so the wind will help distribute the water instead of fighting it. The best way to achieve this goal is to get 90º fittings because you get cleaner hose runs, then place the nozzles so the spray pattern will get as much coverage as possible (your intercooler sprayer is mounted properly and like I described). This is what I have done in the past with inter cooler water sprayers, otherwise the water sprayer was really ineffective at high speeds because the air rushing in was just making it hit only one part of the intercooler.
Sorry I forgot to mention this to you earlier lol.
Was trying to figure out what tire size to go for today. What I know is that
AD08r 265 on 9.5J ET40: No robbing rear
F200 250 on 9J ET30: Tiny bit of robbing rear (marks on outer plastic fender liner).
Then I started comparing thread width, section width and diameter only to get super confused. For instance AD08r in 285 has a more narrow thread width than 265 and almost same as 250 slicks.
EDIT:
Talked with Hankook China. They actually recommended against 285 on 9.5J. So its either 265 or 275.
Another small update is that we increased the angle a little bit on the spoke design.
AD08r 265 on 9.5J ET40: No robbing rear
F200 250 on 9J ET30: Tiny bit of robbing rear (marks on outer plastic fender liner).
Then I started comparing thread width, section width and diameter only to get super confused. For instance AD08r in 285 has a more narrow thread width than 265 and almost same as 250 slicks.
EDIT:
Talked with Hankook China. They actually recommended against 285 on 9.5J. So its either 265 or 275.
Another small update is that we increased the angle a little bit on the spoke design.
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New "sleeper" track wheels and dry time attack tires have arrived. Unfortunately I only got the ET 99% right. The front wheel only clears the damper by a hair (literally), so I will be adding a small 3mm spacer to be safe. This feels a bit silly because if I am going to run a front spacer anyway, I could just as well have gotten a higher ET to leave more space in the rear. Like ET40 or so. Because with ET35 the tire will most likely touch the inner outer plastic fender from time to time. No biggie, these are track wheels only, and wont even be driven to/from the track.
Here's the initial result, 18", 9.5J ET35 without spacers, 275/35R18 Hankook Z214. I would like to thank @barry@3DM and his post here for inspiring me to go with this maxed out square setup one year ago.
Here's a quick comparison between the Z214 and the tires I will use for time attack in case it rains (255/35 PS4).
And some brakepad porn...
Here's the initial result, 18", 9.5J ET35 without spacers, 275/35R18 Hankook Z214. I would like to thank @barry@3DM and his post here for inspiring me to go with this maxed out square setup one year ago.
Here's a quick comparison between the Z214 and the tires I will use for time attack in case it rains (255/35 PS4).
And some brakepad porn...
Torque steer on Z4/E46?
Anyone in here had problems with torque steer on their Z4/E46? After changing the RTAB to bearing type, my car seems to pull left on hard accelleration, no matter the wheel alignment. Worse with spacers rear. No problems going over bumps or anything else - it is strictly related to the right foot. I figured it was caused by the lower control arm inner bushing going soft after 10years and 150,000kms, and perhaps the new bearing RTABs exposed/accellerated the issue.
Anyway, I tried installing below super cheap control arms with bearings, and it seems to have reduced the issue by 50% or so. There are still two rubber bushings left on the car (the upper inner control arm bushings) and I am not sure what can be done about those except replacing with new OEM. I also fail to see how they would affect toe when moving the right foot. The rear subframe has solid bushings.
Anyhow, if anyone can recommend a nicer control arm than the blue chinese $20 heavyweight I got here, I will add those to my shopping list.
Anyone in here had problems with torque steer on their Z4/E46? After changing the RTAB to bearing type, my car seems to pull left on hard accelleration, no matter the wheel alignment. Worse with spacers rear. No problems going over bumps or anything else - it is strictly related to the right foot. I figured it was caused by the lower control arm inner bushing going soft after 10years and 150,000kms, and perhaps the new bearing RTABs exposed/accellerated the issue.
Anyway, I tried installing below super cheap control arms with bearings, and it seems to have reduced the issue by 50% or so. There are still two rubber bushings left on the car (the upper inner control arm bushings) and I am not sure what can be done about those except replacing with new OEM. I also fail to see how they would affect toe when moving the right foot. The rear subframe has solid bushings.
Anyhow, if anyone can recommend a nicer control arm than the blue chinese $20 heavyweight I got here, I will add those to my shopping list.
Thanks alot mate! Really appreciate it. They cost 8k rmb / AUD1700 forged and made to spec, so about the same as the tires. If you go for +10J or add additional weight saving design features (special spokes), they charge extra.
The main intention here of course is to fool the competition and general public into thinking that the car is still bone stock. This is why I am sticking to slight variations over the original oem 293 wheel design while upsizing. I was hesitating forever to get this set because they wont go on the street, and I can only enjoy them for short stints on the track. But I really wanted to take the "sleeper" theme all the way. It is also at the track competitions that all the cameras come out haha.
linky - Turner Motorsports version
Be interested to know how much these generic ones weigh (vs stock ~3lbs each)
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He meant the ones I got. They are definitely heavier than stock.
Thanks for the link @Lurcher what a price difference though
@Asbjorn
So I was thinking about your intercooler spraying setup more, and I thought well since the nozzles sit too close to the radiator or intercooler the standard water methanol jet would not have a wide enough spray pattern to cover alot of space. So I found a 1/8 npt car washer jet that has a fricken humongous spray pattern that should help compensate for such a small gap between the jet itself and the radiator: https://www.alibaba.com/product-detail/1-4-1-8-NPT-or_1619168341.html
Hope this helps, but the problem will probably be a huge water consumption penalty.
So I was thinking about your intercooler spraying setup more, and I thought well since the nozzles sit too close to the radiator or intercooler the standard water methanol jet would not have a wide enough spray pattern to cover alot of space. So I found a 1/8 npt car washer jet that has a fricken humongous spray pattern that should help compensate for such a small gap between the jet itself and the radiator: https://www.alibaba.com/product-detail/1-4-1-8-NPT-or_1619168341.html
Hope this helps, but the problem will probably be a huge water consumption penalty.
Thanks for the suggestion. The two snow nozzles I use now combine to 120cc/min. At the last track session where I used them (ON continuously for +20mins), I got through almost half the washer fluid tank. 20mins x 120cc = 2.4L. I actually enlarged the capacity of the thank with a separate container because there is plenty of space for that in a Z4, but the problem is also I need to add about 1L of ice cubes just to get the water cooler than ambient. The tanks are placed right next to the turbos.
In conclusion I cannot use nozzles that are any larger than what I use now. Perhaps a bit interestingly the coolers were completely dry after the session although +2Ls of water was consumed.
Judging by the last log, it also looks like I have a slight imbalance in cooling capacity. Perhaps too much cooling capacity for the DCT while not enough for water. I say this because whenever the DCT cooler turns on (@100C) the dct temp either stays there or falls below 100C. It never goes above say 105C. Coolant however climbs way above the setpoint of 80-90C.
So in conclusion I would probably benefit more from converting to an MT style radiator than fidling with the nozzles. I am not sure though because the DCT would still be part of the coolant circuit through the heatexchanger. Previously I also tried moving the dct cooler downwards and out of the direct airflow from the kidneys to get better water cooling. I ended up regretting that because then instead of only having coolant overheating I got both coolant and dct overheating haha. That was when I moved the dct cooler back up and added better aux coolers instead. Long story short, the dct core of the radiator may not get much airflow that it will make a huge difference anyhow. But it is well known that AT N54 cars overheat earlier than MT, and it does represent 14% or so of the main radiator area.
So the heavy generic arms started making super loud bearing noises after one week or so. They also didn't solve the problem I have where the car pulls slightly to the left when accelerating. Im now suspecting a bend front left upright to be the root cause instead. Anyhow, Im going back to the stock lower rear arms, but having the rubber changed to bearing-type instead.
Will probably do the same for the rear upper arms. Might do the @fmorelli mod and make them adjustable as well. Waiting for a quote on that job.
Im also thinking of having the rear damber mounts modified to bearing type. After 10 years of use I assume the rubber has become pretty soft. Not sure if anyone has any experience with these?
Then going back to the front of the car. After raising the front back to stock height, I lost some camber. I went from -3deg to -2.5 or so. Ideally I would be running more than -3deg, but the "street" ground control camber plates don't allow that.
Since bimmerworld wouldn't accept my credit card and vorslagh don't ship to China at all, I had these custom made locally to see if I can get some camber back. Im pretty excited about the result.
Pretty....
They do make a bearing rear set - let me go see if I can find, was looking at them last week
Well - may are selling a 2 bolt bearing set that they say will fit, as most other BMWs use a 2 bolt mount apparently Turner rear strut mount
They do make a bearing rear set - let me go see if I can find, was looking at them last week
Well - may are selling a 2 bolt bearing set that they say will fit, as most other BMWs use a 2 bolt mount apparently Turner rear strut mount
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I got a quote to have the stock ones rebuilt locally with pillow balls. Cost is pretty similar to those turner ones, which probably don't fit E89? E89 is not listed as compatible in that link.
Anyhow I will get them out first and see if they look worn.
Yea, once again we have something "special", though I do feel the 3 bolt mount is better. Probably just kidding myself, but why would BMW make something like this just for a low # car?
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