Nullbar, hardly any other name stands in the car tuning scene for deep, no extremely deep cars, like Nullbar. The Stutz brothers are behind the online store from Höchst in the Odenwald. Since 2002, they have specialized in the sale and development of threaded and air suspension systems with their company Streetec.
Both of us were very familiar with the online store from our own tuning days. For example, we did a few photo shoots on Lake Wörthersee of vehicles with Streetec suspensions.
We had also briefly looked into installing an air suspension on the rear axle in our Grand California, as it promises a higher payload and better ride comfort. To date, however, we could never commit to a provider, perhaps that was exactly, determination or luck, because by pure coincidence we became aware of an Instagram post from Streetec. We couldn’t believe this coincidence, the guys really post a picture of a Grand California with a Streetec off-road air suspension, titled as a test vehicle.
I was immediately on fire and wrote an email to Sven from Streetec, meaning: “Shut up and take my money!” 😅
What better can there be, please! A full air suspension for our Grand California.
But now let’s go a bit into the facts about the chassis.
One more thing: Rarely have we covered such a complex topic in our blog as this report. We could write pages about the controls alone. Therefore, we decided to split the topic into a few posts and videos. Long texts are not only exhausting to write, but even more so to read. Many requests have already reached us via Instagram, questions about questions, so this post gives the most important info.
The chassis components at a glance
The Streetec off-road suspension consists, in addition to the dampers and air bellows, of an air generation kit. The air generation kit forms the core of the chassis installation; in addition to an air tank, it contains, among other things, the control unit that monitors the air levels or vehicle height.
Shock Absorber & Air Bellows
Streetec makes no compromises when it comes to chassis parts, working only with the best suppliers in the automotive industry. The shock absorbers are manufactured in cooperation with Bilstein (in future with KW) and the air bellows with Continental. This means that the absolute top players are used here.
The air generation kit
Already mentioned at the beginning, the air generation kit is the heart of the chassis, it consists of a tank, an air compressor, the control unit and a valve block. Streetec also surprises at this point, the parts are all assembled and mounted in Höchst, for example, the motherboard is completely developed and assembled in-house. Of course, like most electronic components, the chips come from the Far East. However, the development is completely in House. Through this process, Streetec can monitor everything from development to installation in the vehicle.
The software
Nothing works without it nowadays, not even with a chassis that regulates itself fully automatically. You know who programs the software, don’t you? Yeah right, Streetec.
There are two ways to control the chassis. First, a display is mounted in the vehicle, through which all settings can be made.
You can also control the chassis via your smartphone, using the autoleveling app from Streetec. The app connects to the control unit via Bluetooth and displays the same view as on the display in the vehicle.
The installation
The installation was carried out on site at Streetec in Odenwald. If you decide to rebuild after reading this report, please plan on having your vehicle on site for the entire week. The matter is more complex than you might think, because the entire rear axle is rebuilt. For example, the leaf springs disappear completely, but we go step by step 🙂
1. damper for the front axle
The first step is to replace the dampers on the front axle, swapping the original struts one-for-one for the Streetec components.
2. conversion of the rear axle
In the second step, the rear axle is rebuilt.
This involves replacing the original shock absorbers and removing the leaf springs. The springs have to give way to the completely new air bellows mount, this is where Streetec’s suspension differs from most air spring retrofits. There, it is common practice to mount the air bellows in addition to the leaf springs.
The picture shows an exploded view of the new rear axle, good that the guys know what to do. 😅
The new image, on the right side the air bellows finds its home. In order for the bellows to be connected to the vehicle, the new frame mount is still missing.
Factory existing holes are used for mounting, so don’t worry, nothing is drilled into the vehicle here.
By removing the leaf springs, the rigid rear axle would not have enough support on the chassis only by mounting the air bellows and would not be able to transmit lateral forces, for this reason a new cross brace including Panhard rod is installed.
The cross-bracing serves several purposes. Sensors are mounted there so that the control unit knows how high the individual axes are. Depending on the angle, the exact height can thus be calculated.
3. assembly air generation kit
For a long time, we racked our brains as to where and how all the components for air generation could be accommodated in the Grand California. The answer is short and sweet, not at all! Mounting inside would have involved the loss of an enormous amount of storage space. Streetec bolted all the components to a special bracket designed for the Crafter, which in turn is attached to the underbody of the Grand California. This saves space inside and the need to lay cables in the interior.
So compressor, valve block, tank and co find their place. We anticipate snapping at this point, important parts, such as the compressor or the valve block, are protected by an aluminum cover and thus secured against stones and co.
Since the system is an air pressure system and air contains water, condensation is a natural byproduct of compression and air storage in a tank. For this reason, the air generation kit has a water separator, however, over time, some water may collect in the tank, which could freeze in the winter. But do not panic, the tank has a drain plug and so the problem can be prevented in advance. Streetec recommends opening the tank every six months to drain any condensation that may have formed.
4. power supply
You guessed it or? We need electricity! The compressor and the control unit are connected directly to the starter battery. To ensure that the control only works when the ignition is switched on, ignition plus is taken from under the driver’s seat. Thus: Ignition on = Chassis on 😊
The most important facts in conclusion
Of course, it’s nice that our Grand California is able to adjust its ride height with the suspension. However, the best feature by far is the automatic vehicle leveling.
The leveling
Surely most of you have wedges on vacation with you, so that in the case of a pitch with slope, the inclination can be compensated. Wedges are simply annoying, eternal up and down until the car is in the balance at the end. Great, because now you can leave the parts at home and use them as potted plant coasters.
With the Streetec undercarriage, you simply place yourself at your desired location, select leveling in the control menu, and let the magic happen. Using the installed tilt sensors, the control unit calculates how much pressure has to be pumped into the individual air bellows so that the vehicle is completely level. The first step is always to try to fill the air bellows with air and thus compensate for the misalignment. Only when the maximum height has been reached and this has not been sufficient, an attempt is made to reach the desired position by means of pressure release. There is a purpose behind this procedure: the fuller the air bellows, the more stable the vehicle is and therefore less likely to sway due to movement in the interior. In our initial tests, this worked great.
Here you can see an example of leveling:
- Vehicle not leveled
- Vehicle leveled
What height adjustment range does the chassis offer?
Of course, the adjustment range is just as interesting as the leveling. The vehicle offers four different driving modes.
- Ride
This is the registered ride height, which is not significantly different from the original chassis. - Low
The name says it all: this setting lowers the vehicle by about four centimeters. Maybe this function could be useful at one or the other toll station or ferry 🫣 - High
In this setting, the chassis travels to the highest point, allowing for safer off-road driving. - Manual
Here you have the possibility to control each bellow individually. This can be done either per bellows or per axis, as already described.
In total, the chassis has an adjustment range of around eleven centimeters from the lowest to the highest point. So the distances from the edge of the fenders to the center of the wheel with empty air bellows are 400mm at the front and 390mm at the rear. With maximum air filling, the distance front and rear is 510mm.
Expert opinion and registration
The complete conversion has a certificate according to §19.3 StVZO, so a registration with an official testing organization is possible without problems. The maximum axle load is 2100 kilograms at the front and 2380 kilograms at the rear, so a load increase to 4.48 tons is easily feasible.
The driving behavior
What can we say! The Grand California already drives much better than the competition with its standard suspension, but after the conversion it’s another level. Especially the behavior on the rear axle is a dream, potholes are now bearable for the driver and interior. 😅
The price
You were waiting for the point, weren’t you? The price tag for the suspension including installation, wheel alignment and registration is currently 9800 euros. For a detailed offer please contact the company Streetec directly.
Now we have tried to answer the most important questions in a first article and hope very much that we have succeeded. But there is so much more to write about and show, be it the automatic height regulation when loaded or driving without air in the event of a fault. We will cover these topics in more detail in the coming weeks. If you have any special questions, feel free to use our contact form or just leave a comment. We will then try to help accordingly.
4 comments
O ile wzrasta ciężar auta po montażu zestawu ?
Pozostaje bez zmian, oryginalne sprężyny są znacznie cięższe
Wie verhält sich das Auto bei Fahrversuchen?
Genehmigung ? Sicherheit?
Für Ihren ausführlichen und aufschlussreichen Kommentar wäre ich Ihnen sehr dankbar
Wie lange dauert die Installation des Systems beim VW GC 600 und wie hoch sind die aktuellen Kosten?
Beste grüße
Piotr Gadziński
Hallo Piotr,
Der Wagen fährt viel ruhiger durch die Kurven. Insbesondere bei Beladung merkt man einen deutlichen unterschied.
Das Fahrwerk hat ein EU Gutachten und kann somit problemlos eingetragen und gefahren werden. Der Einbau dauert ca. 1,5 Tage und du musst mit kosten von rund 10000 Euro rechnen.
Lieben Gruß