# One Month Later, Some E-level Thoughts



## baconfenders (Dec 16, 2010)

I ended up keeping the E-level management and everything is installed; has been for about a month now. Front sensors are mounted directly behind the strut; rears on the lower control arm in accordance with OVRWRKD's excellent E-level DIY.

I realize that Accuair E-level is a *height based system*, not a PSI-based system like manual setups or Autopilot V2.

I noticed something interesting with the E-level calibration procedure. When it runs an autocal, it saves three presets. IIRC, 10% (1), 50% (2), and 100% (3) of sensor travel are the predetermined preset values. Depending on the car and positioning of the sensor, each car is unique. Even two R32s with the same E-level setup will vary since no two car's sensors are in _exactly_ the same position. I have two PSI gauges although they are not needed. They are strictly for monitoring system pressures at all four corners of the vehicle.

Take the autocal 50% preset (2); I noticed that the two front bag's PSI is different slightly left-to-right. The rear PSI values autocal to roughly the same PSI. Is this normal? That was the inital question I had after I initially calibrated the system (yes, on a flat surface). Could the slight difference in front PSI autocal settings be because the right air line is slightly longer, resulting in slightly more pressure to maintain the same height?

After a while using the autocal presets, I moved on to fine-tuning the heights using a tape measure. I set preset 2 to 23.5" FTG front and 23.75" FTG rear. The difference side-to-side is further evidenced when a tape measure is used to set the best aesthetic height for each wheel. Sometimes the difference can be even greater (as much as 30 PSI) when a tape measurer is used to verify ride height left-to-right. Again, all on a flat surface.

I am using the preset 2 during daily driving and the car is straight and true. It does not pull left or right at all. Which is a total mind **** considering the large differences in PSI left-to-right. The gauges are ran direct from the ports on the VU4 manifold.

Preset 2 (not an autocal, the one set with a tape measure):








(left gauge is front left and right, right gauge is rear left and right)

I would appreciate any thoughts. I suppose those with E-level but no gauges would never notice the differences? I wonder if the engine load in the front of the R32 is off center? Certainly the rear of the MkV is off center (anyone running max camber on the MkV Golf is keenly aware of this fact).

Interestingly, Accuair mentions this in their FAQ:



> *Air spring pressure readings are absoultely irrelevant when it comes to setting the height of a vehicle because they vary with load and temperature, (two conditions that will be constantly changing on every vehcile). Most vehicles have unequally loaded corners due to offset fuel tanks and other components which can require as much as 15 psi differential between sides to get the vehcile level. We see no need to display these variations because they are simply confusing and unnecessary.*












:beer:


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## darcness (Aug 8, 2008)

Another thing to consider is if you're running sway bars or not. If you're running sways they are going to make it much harder to level things out. The PSI differences will come from the air ride fighting with the sways. Since the sways basically make your suspension (side to side) a more cohesive unit, changes to one side are going to inevitably affect the opposite side.

I myself run front and rear sways with my BOC setup. I'm running manual management so the only way for me to "level" things out is to actually measure it physically. I found that in the front I'm about 1/4 to 1/8" off at the same PSI in the front bags. In the rear it's about 1/2" difference at the same PSI. I've found that no matter what I do to the PSI in the rear the sway bar simply will not allow me to get a perfectly even ride height from side to side. The front is closer so I don't worry about it too much.

Also I've noticed that almost all MKV's exhibit this difference in the rear. Usually about a 1/2" difference, drivers side being lower, passenger side higher. I've seen that backed up by other measurements as well.


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## baconfenders (Dec 16, 2010)

darcness said:


> Another thing to consider is if you're running sway bars or not. If you're running sways they are going to make it much harder to level things out. The PSI differences will come from the air ride fighting with the sways. Since the sways basically make your suspension (side to side) a more cohesive unit, changes to one side are going to inevitably affect the opposite side.
> 
> I myself run front and rear sways with my BOC setup. I'm running manual management so the only way for me to "level" things out is to actually measure it physically. I found that in the front I'm about 1/4 to 1/8" off at the same PSI in the front bags. In the rear it's about 1/2" difference at the same PSI. I've found that no matter what I do to the PSI in the rear the sway bar simply will not allow me to get a perfectly even ride height from side to side. The front is closer so I don't worry about it too much.
> 
> Also I've noticed that almost all MKV's exhibit this difference in the rear. Usually about a 1/2" difference, drivers side being lower, passenger side higher. I've seen that backed up by other measurements as well.


Thanks for the input dude, very interesting observations. I didn't even consider the FSB and RSB.


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## baconfenders (Dec 16, 2010)

Just occurred to me that another attributable cause of the large difference left to right in the front could be caused on the length of the air line to the right bag. All four of my lines run out of the same grommet. The left front line runs out this grommet directly to the bag. Roughly 5 feet of line. The right front line runs out of the same grommet, but cuts over to the right side of the car in the rear, and then up to the right front bag. I would guess maybe 7 feet line. So a 2 foot difference in line length left to right.

Of course all things factor in that contribute to the error in PSI between sides. None of which affects the handling of the car whatsoever. In fact it handles BETTER with left and right differences in pressure, instead of arbitrarily setting the front and back to the same preset (e.g. 60f/40r).


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## GolfL (Apr 7, 2012)

I have the exact same thing with my V2.

If i set the pressure on LF 3.4 RF 3.4 and RL 4.5 RR 4.5, the front passagerside is 5mm higher then driverside. And the passager rear is about 10mm higher than drivers side.

I could set the pressure on LF3.4 RF 3.1 and RL 4.5 RR 4.0, but the V2 is then struggeling more to reach this preset. 

quite annoying.


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## baconfenders (Dec 16, 2010)

GolfL said:


> I have the exact same thing with my V2.
> 
> If i set the pressure on LF 3.4 RF 3.4 and RL 4.5 RR 4.5, the front passagerside is 5mm higher then driverside. And the passager rear is about 10mm higher than drivers side.
> 
> ...


Car in question:










Love it! Thanks for chiming in, interesting that V2 has similar issues. Seems airride accuracy is a mean, not an end.


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## Yuripolak (May 30, 2008)

I'm a future air rider but I really think that there's no alignment issues at all with pressure differences...

but, how about the spring rates? 30 psi diff between sides may lead to stability issues due to different spring rates?


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## baconfenders (Dec 16, 2010)

Spring rate was a concern to me, given the large difference in psi. But as far as I can tell, it feels even.

What I did not do was set the presets with someone in the driver seat...


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## cflrabbit (Nov 4, 2009)

Do you adjust ride height after initial air up? When you change the suspension geometry drastically (I.e. laid out to ride height) while stationary components tend to bind. Once you drive they'll even out. Perhaps this is playing in to the pressure discrepancies.


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## baconfenders (Dec 16, 2010)

cflrabbit said:


> Do you adjust ride height after initial air up? When you change the suspension geometry drastically (I.e. laid out to ride height) while stationary components tend to bind. Once you drive they'll even out. Perhaps this is playing in to the pressure discrepancies.


How did you find this? 

Anyway no, no adjustment after preset called. The needles are split like that from the get go on even ground. The front are both equal in height, yet there is a 30 psi differential left-to-right. Very odd.


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## cflrabbit (Nov 4, 2009)

Very odd indeed. If you set the fronts to the same psi, how off is the height?


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## ForVWLife (Nov 12, 2004)

RU1NED said:


> How did you find this?
> 
> Anyway no, no adjustment after preset called. The needles are split like that from the get go on even ground. The front are both equal in height, yet there is a 30 psi differential left-to-right. Very odd.
> 
> ...


does it happen everytime? 

what happens if you air up to a preset then adjust to a different preset?


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## rollininstyle2004 (Jun 8, 2005)

Did you end up doing the install yourself? I remember you looking for someone to do the install a while back. I am about to do an E-Level setup on my A6 in GA, debating whether or not to tackle it myself.


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## baconfenders (Dec 16, 2010)

rollininstyle2004 said:


> Did you end up doing the install yourself? I remember you looking for someone to do the install a while back. I am about to do an E-Level setup on my A6 in GA, debating whether or not to tackle it myself.


I did the e-level install myself yeah. A buddy of mine assisted me. But there's only enough room in there for one guy to work. I'm glad I did it myself. It seems very complicated but in hindsight it was a breeze. Just plan it out. And don't rush. Run the system in manual if you don't finish it in time.

I see you are in Atlanta. Be happy to help you out if you need a hand.


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## [email protected] (Feb 10, 2012)

RU1NED said:


> I noticed something interesting with the E-level calibration procedure. When it runs an autocal, it saves three presets. IIRC, 10% (1), 50% (2), and 100% (3) of sensor travel are the predetermined preset values. Depending on the car and positioning of the sensor, each car is unique. Even two R32s with the same E-level setup will vary since no two car's sensors are in _exactly_ the same position.


 The purpose of the first step of the calibration (max height, then min height) is to eliminate all of these sensor installation variations that you are referring to. Meaning it doesn't matter if you have 2.5" of total sensor travel on the RF and 2.0" of total sensor travel on the LF. The system spans each specific sensor travel to 100% (assuming that you have more than 1" of total change, anything less and the system will give you a sensor travel warning during calibration). 



RU1NED said:


> Take the autocal 50% preset (2); I noticed that the two front bag's PSI is different slightly left-to-right. The rear PSI values autocal to roughly the same PSI. Is this normal? That was the inital question I had after I initially calibrated the system (yes, on a flat surface). Could the slight difference in front PSI autocal settings be because the right air line is slightly longer, resulting in slightly more pressure to maintain the same height?


 This PSI difference is primarily due to unequal weight distribution in the vehicle (infact it is almost unheard of for a vehicle to have equal side to side distribution). The line length plays zero roll in that pressure difference you are seeing. Depending on your line size and length variations you may or may not see a variation in the speed that the bags fill compared to one another, but other than that line length really has no affect. 



RU1NED said:


> I am using the preset 2 during daily driving and the car is straight and true. It does not pull left or right at all. Which is a total mind **** considering the large differences in PSI left-to-right. The gauges are ran direct from the ports on the VU4 manifold.





RU1NED said:


> I wonder if the engine load in the front of the R32 is off center? Certainly the rear of the MkV is off center (anyone running max camber on the MkV Golf is keenly aware of this fact).


 Correct! 



darcness said:


> Another thing to consider is if you're running sway bars or not. If you're running sways they are going to make it much harder to level things out. The PSI differences will come from the air ride fighting with the sways. Since the sways basically make your suspension (side to side) a more cohesive unit, changes to one side are going to inevitably affect the opposite side.


 Actually, unless your sway bars are bent or the car is bent (i.e. been in a gnarly accident), the sway bars should work to keep the car level rather than un-level. You can easily confirm this by setting the car level at the fenders and then disconnecting the sway bar on one side and seeing if it wants to stay lined up, or if it is in a bind to get the bolt back in. 



Yuripolak said:


> I'm a future air rider but I really think that there's no alignment issues at all with pressure differences... but, how about the spring rates? 30 psi diff between sides may lead to stability issues due to different spring rates?


 So this is a great question and if I can explain it well enough below, than all of you readers are going to have a lot better understanding of how air suspension works and why the e-Level system ALWAYS always makes for the most accurate and best handling vehicle on air suspension :thumbup: 

Here we go... 
So the whole idea behind air suspension is ride vs. load decoupling. In other terms, the vehicle should ride the same with no load as it rides with a full load. Here is the engineering behind it: 

Ride Frequency = Spring Rate / Vehicle Mass 

As you add Mass (or load) to a vehicle with air suspension, a height based controller will automatically add air to the air springs to keep the vehicle at target height. The extra air in the air spring adds pressure which in-turn increases the stiffness (spring rate). 

So with a properly designed air suspension, Ride Frequency (or ride quality) stays consistent no matter how much load is in the vehicle. This exactly why you guys have observed when the vehicle is level, yet has extra pressure on the heavy side it handles incredibly. 

In contrast, this is also why some of you have observed that when the vehicle has equal pressures, yet is not level it handles like crap... Because one whole side of the vehicle is moving at a different Ride Frequency than the other. 

I would be happy to expound on this if anyone needs further explanation. 



cflrabbit said:


> Do you adjust ride height after initial air up? When you change the suspension geometry drastically (I.e. laid out to ride height) while stationary components tend to bind. Once you drive they'll even out. Perhaps this is playing in to the pressure discrepancies.


 This is also a great point. There will always be significant suspension bind on the initial adjustment. This is exactly why the RideMonitor Mode that e-Level has is critical... As you begin driving the suspension bind will free up and the car will rise. The RideMonitor Mode will see this and make the necessary corrections to keep your suspension in alignment and give the car a very consistent feel. 

I sure enjoy seeing all of these great questions and great responses! It makes me happy to know that we have customers that actually care about the details :beer:


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## baconfenders (Dec 16, 2010)

Reno, thx for taking the time to clarify and answer my questions. Love my setup so far! 


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## Yuripolak (May 30, 2008)

perfect! 
this makes me think that it worse every penny paid on e-level.. can't wait to get it installed on my ride... :beer:


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