Big discrepency between trip computer and real mpg since Van Aaken box

[czar]

My trip computer and real mpg (calculating by hand) were extremely close before I installed my Van Aaken; I beleive someone must have adjusted it before I bought the car since it was so accurate.

Since installing the Van Aaken tuning box, I am getting hugely skewed numbers. I am extremely careful filling my tank to the brim, so I know my calculations are accurate. On my last series of fill-ups, I am getting 42.xx wheres as the trip computer shows 58.x That's about a 40% discrepency. Although unscientific, when I temporarily uninstalled the VA box, I noticed the trip computer showed lower #'s.

I forget what I did, but I lost my VAG-COM coding (e.g., fob no longer operates windows) - I think I disconnected battery - anyway, I'm wondering if this is a mix of losing that coding and that the VA box does something to make it read higher?

 

[Lug_Nut]

Using Sprint 520 (.205) nozzles makes my MFA display about 15% higher numbers, seemingly better mpg, until the re-fill calculation shows that there is little real difference from the stock (.184) nozzles.

 

[heno]

My trip computer and real mpg (calculating by hand) were extremely close before I installed my Van Aaken; I beleive someone must have adjusted it before I bought the car since it was so accurate.

Since installing the Van Aaken tuning box, I am getting hugely skewed numbers. I am extremely careful filling my tank to the brim, so I know my calculations are accurate. On my last series of fill-ups, I am getting 42.xx wheres as the trip computer shows 58.x That's about a 40% discrepency. Although unscientific, when I temporarily uninstalled the VA box, I noticed the trip computer showed lower #'s.

I forget what I did, but I lost my VAG-COM coding (e.g., fob no longer operates windows) - I think I disconnected battery - anyway, I'm wondering if this is a mix of losing that coding and that the VA box does something to make it read higher?

When I bought a Quadzilla XZT+ box for my Dodge Cummins my mileage went through the roof. I had to make corrections in my ScanGauge II to get it back in line.
These boxes are fooling the ECM so they're also fooling any gauge calculating mileage via the ECM.
Mike

 

[czar]

THanks for that info guys. I figured it had to be messing with the calculation somehow. Unfortunately, I went some time without calculating by hand, so I thought I was getting a huge improvement. Turns out that's not the case. Oh well, the VA box makes the car more fun to drive.

 

[tdi_dave_FL]

Van Aaken Box

Hey Everyone,

I was wondering.... what mileage increas/decrease on average have you experienced with the Van Aaken Smartbox? I just installed one that I got on eBay today, and love the difference it makes in the drive of the car. Also, did you bother to install the switch..... I really don't see a reason for it, It seems to improve the drivability of the TDI in city traffic tremendously. I am also going to switch to the OEM fit K & N air fliter tonight too... be interesting to see the results of the combination. More to follow

 

[dieseldorf]

I am also going to switch to the OEM fit K & N air fliter tonight too... be interesting to see the results of the combination.

What benefit will you find with this type of filter?

 

[david_594]

All boxes lie to the ECU about the actual fueling.

The only way to keep an OEM trip computer accurate is with chip tuning.

 

[Windjammer]

what 'benefits' do you expect me to find/not find?

I expect you to be buying a new maf sensor because the filter oil ruined you existing sensor.

 

[rustytigwire]

My Van AAken (used) is on the way. What is all this trip meter error stuff?

OK...fill me in on the gotchas for this item an potential resolution of same.

AND, someone please give me installation guidance as I am willing to guess but that has taught me over many mistakes to ask first.

03 Golf 5 spd, 47.7mpg last tank trip to MO. turnpike 75 mph avg little bit of backroads (for non oklahoma available fireworks)

 

[scooperhsd]

Hey Everyone,

I was wondering.... what mileage increas/decrease on average have you experienced with the Van Aaken Smartbox? I just installed one that I got on eBay today, and love the difference it makes in the drive of the car. Also, did you bother to install the switch..... I really don't see a reason for it, It seems to improve the drivability of the TDI in city traffic tremendously. I am also going to switch to the OEM fit K & N air fliter tonight too... be interesting to see the results of the combination. More to follow

K&N + TDI = not good. Your stock airfilter
A) flows MORE air
B) filters better.
C) won't put oil on the MAF, thereby requiring early replacement of the MAF

Basically, there is no gain to be had with adding a K&N .

 

[06SpiceRedTDI]

My Van AAken (used) is on the way. What is all this trip meter error stuff?

OK...fill me in on the gotchas for this item an potential resolution of same.

AND, someone please give me installation guidance as I am willing to guess but that has taught me over many mistakes to ask first.

03 Golf 5 spd, 47.7mpg last tank trip to MO. turnpike 75 mph avg little bit of backroads (for non oklahoma available fireworks)

I think the czar is referring to the readout of his MFD in his 05.5 Jetta. You shouldn't have to worry about this in your 03 as they didn't come with any kind of MPG computer, and I think this margin of error could be calibrated out of a scanguage.

 

[dparker]

I expect you to be buying a new maf sensor because the filter oil ruined you existing sensor.

You must be a dealer service tech. They tried to charge me for a MAF sensor because I had a K&N. A month later I got a recall letter saying they had a defect on my cars MAF sensor. If properly oiled a K&N will not damage it.

 

[tdi_dave_FL]

We'll see what happens, 8500miles since the K&N change... So, honestly... how many of you have experienced (First Hand) MAF failure due exclusivley to a K&N Filter. I have looked at the MAF sensor (Orig since I bought the car in Mar of 2004.... 103,500mi ago) I see no evidence of oil or other contamination.

 

[lekolite]

Maybe K&N kills mafs, maybe not. Thats your risk.

Another question is does it filter as well as stock paper? Remember your oil changes are at 10k, not 3k as on a gasser. More time for dirt build up and damage. Again, your risk.

And finally, does the K&N really flow more than the stock? And if it does, can the engine benefit from it at all? No risk there really, unless you count looking silly.

 

[wjdell]

A well prepared Puffer Fish is safe to eat. Come over I will show you how to clean one, blindfolded.