Was, Schrick VGI GB, now show us yours!

[jedi-knight83 0]

It may just have been a bad time - if all the visible GPS satellites were over in one particular quadrant of the sky the readings would be pretty innacurate..

 

ok my last post on speedo inaccuracy before i go too far off topic..... :roll:

 

it wasnt just one time, its every time i use it and the difference is always 10%. i dont see how the speedo and the revs can be inaccurate and mine is doing 100mph on the speedo at 4000rpm....so it must be my satnav that is wrong??? unless my car is completely goosed and all the readings are wrong.

[Kevin Bacon 5]

It may just have been a bad time - if all the visible GPS satellites were over in one particular quadrant of the sky the readings would be pretty innacurate..

 

Why does that matter? 2 and 3-D Trilateration GPS relys on the seeing 4 or more satellites to work out where it is on the Globe. So shouldn't matter how many there are in one particular quadrant and, besides, all 24 available satellites were orbited as such so that 4 are visible at any point in time, anywhere on the globe.

 

As I said earlier, the discrepency is unliklely to be GPS related. It's tried and trusted technology, second only to laser telemetary.

 

K

[Jim 1]

I might be wildly wrong, but can't the GPS recievers in the car be 'out of alignment' - a friend of mine recently had to get his GPS setup reconfigured after having removed from his Merc and installed in his new BMW... it kept telling him to take the turn offs for junctions after he had gone past them? Could a similar fault be causing the same problem?

[Supercharged 2]

dr_mat wrote:

It may just have been a bad time - if all the visible GPS satellites were over in one particular quadrant of the sky the readings would be pretty innacurate..

 

 

Why does that matter? 2 and 3-D Trilateration GPS relys on the seeing 4 or more satellites to work out where it is on the Globe. So shouldn't matter how many there are in one particular quadrant and, besides, all 24 available satellites were orbited as such so that 4 are visible at any point in time, anywhere on the globe.

 

As I said earlier, the discrepency is unliklely to be GPS related. It's tried and trusted technology, second only to laser telemetary.

 

K

 

Tsh... and he calls himself a doctor...

 

:lol:

[jedi-knight83 0]

it kept telling him to take the turn offs for junctions after he had gone past them? Could a similar fault be causing the same problem?

 

my GPS is spot on, corners, roundabouts, etc.... all where they should be and up to 60 mph the speedo is the same as the gps. just after 60 -70 you can see the difference get larger

[dazzyvr6 0]

both of my gps systems seem accurate,same as my speedo give or take a few mph

[dr_mat 0]

It may just have been a bad time - if all the visible GPS satellites were over in one particular quadrant of the sky the readings would be pretty innacurate..

 

Why does that matter? 2 and 3-D Trilateration GPS relys on the seeing 4 or more satellites to work out where it is on the Globe. So shouldn't matter how many there are in one particular quadrant and, besides, all 24 available satellites were orbited as such so that 4 are visible at any point in time, anywhere on the globe.

 

 

I know. But it also relies on having a large enough subtended angle between those four satellites in order to perform an accurate positioning calculation. It's gotta solve an equation, after all, and if it's got crap data, it can't solve it accurately. I worked with GPS during my PhD (before they turned off spoofing, admittedly), and it was shockingly inaccurate. Even differential GPS (immune to spoofing) was prone to drastic errors if you didn't have a statisticaly nice spread of satellites.

 

We used to use laser ranging data for the satellites, and that was much more accurate (a few cm over 1300km).

[Joe M 0]

Its fitted, 4 hours and many cuts on fingers later. Them bolts on the front of the manifold are a nightmare. :evil:

 

Still to fit the vacuum tank and control unit but so far it drives well up to 4000, then dies. Like a mini turbocharger at 3000, no pinking and I havent done an ecu reset either. :shock:

[VR6 0]

Its fitted, 4 hours and many cuts on fingers later. Them bolts on the front of the manifold are a nightmare. :evil:

 

Still to fit the vacuum tank and control unit but so far it drives well up to 4000, then dies. Like a mini turbocharger at 3000, no pinking and I havent done an ecu reset either. :shock:

 

If you've had the battery off for installation, surely that's the ECU reset?

[Joe M 0]

I left the battery in place as I knew I probably wouldnt have time to do the wiring.

[dr_mat 0]

Still to fit the vacuum tank and control unit but so far it drives well up to 4000, then dies.

 

I think this is as expected... That why it has to switch to the alternative manifold path to get reasonable performance above 4k rpm..

[Joe M 0]

Yeah, was exactly as I expected. Still good to feel the difference it makes under 4k though. 8)

 

Wheres your vacuum tank mounted btw?

[dr_mat 0]

Mine was attached to the fuse and control relay - I think it's the fan control relay? The black plastic one under the bonnet on the right hand side, in front of the coolant expansion tank.

[Kevin Bacon 5]

I left my battery connected throughout the operation, even when splicing the ECU signal and power wires, LOL! The ECU will get it's reset when you hoik the big plug out of it :lol:

 

Did some more testing tonight. Speedo is 3-4 mph over reading as per earlier findings and interestingly, the GPS mph is exactly the same as the MFA speed reading. So it looks like VW engineered a slight over read in the analogue dial and the actual calibration is very accurate - on standard wheels and tyres that is.

 

On a more interesting note, the engine just seems to be getting faster and faster. Acceleration in 2nd and 3rd is awesome and it hasn't even been chipped yet! I reckon with Phat's 3:94 diff, acceleration would be brutal :D

 

You can see where the vacuum pot is mounted in my pics on page 12..

 

K

[Joe M 0]

Cool, was gonnae try an squeeze mine onto the strut tower between the washer bottle and coolant tank but that looks like the plcae it will probably end up.

[Kevin Bacon 5]

Nah, try and keep all the wires and vacuum lines as short as possible for better response :D

[dr_mat 0]

Does your car come with a "little devil" and "little angel" attachment, kev? It certainly seems to be schizo...

[PhatVR6 0]

Brutal is the word! oh, and i've got it running now too, so with a long shift tonight it'll be ready for inters after all.

 

 

Hmmm, tyre testing anyone? :mrgreen:

[PhatVR6 0]

Have you all mounted the controller inside the car so you can see the light changing colour?

[Kevin Bacon 5]

No mine's in the engine bay. I was going to extend the LED wiring into the car but after discovering they've filled the entire control box with epoxy resin to water proof it, I abandoned that plan!

[PhatVR6 0]

ah, feck, I was going to do that too!

 

My mate said the controller is sh1t anyway, he was going to design another one, with a digital readout and a dial so you can adjust the switchover point really easily and experiment with it a bit.

[Joe M 0]

Finished mine today. 8) The wiring was probably the easiest bit of the fitting.

 

Have to say im dissapointed with the vacuum hosing though, will need to get some new stuff. :mad: The hose that goes to the brake servo line fits the vacuum tank fine but is very loose at the other end. The other hose is loose on the vacuum tank but fine at the solenoid.

My car also seems to have lost a bit at the top end but it could just seem that way down to the extra grunt down low or maybe my ecu's still adapting... :?

[corradovr6sc 0]

can the hose be clamped?

[Joe M 0]

It can be at the brake sevo valve thing but I dont think it will work at the vacuum tank though due to the shape of it. I'll give it a go tommorow.

 

Will also get a pic of what happens to your bonnet if you dont cut a section out. :lol:

Was intentional, I spoke to another vw specialist that said let the schrick make its own space.

[corradovr6sc 0]

Got mine today :D Fitted the manifold but still got the wiring to do. Agree about the vacuum lines. Managed to fit the cable tidy so it looks neat too.