GPS Speed Adapter for the most uncommon mods

Here's one for those who like to swap modern EFI's into things that might not use a transmission, or way to feed the ECM a corrected Vehicle Speed Signal. In my case it was a boat, and I tested several of the latest GPS speedo converters out there. However the wave pattern was always wrong for my late model engine, so the ECM wouldn't recognize the pulse signal.

Then I found this GPS-50 from Dakota Digital.

Has a built the built in GPS antenna, plus an accelerometer that kicks in if sat signal is lost. I've used one for 2 years now, mounted under a 1" thick fiberglass dash. Amazing little box that will pump out about any wave type or resolution you'll every need. Just one wire to the ECM VSS signal, 12v hot, ground, match up the pulses per mile and your done.

I don't work for them, or receive a dime from DD. Just like their stuff cause every time I've need some sort of special adapter, they say "we make that." And when ya like to DIY crazy builds like myself, it's cool to speak with someone who understands what your actually doing..

That's my tip of the day.

:thumbsup:

-K

I was recently thinking about a VSS solution for a marine application. I'm only in the idea phase for now. One idea that I have is to use the TPS output (0 ~ 5 VDC) as an input for a DC motor controller. I'm thinking the computer TPS circuit would not provide enough current for even the smallest of DC motors? The DC motor controller will speed up / slow down a small DC motor mechanically connected to spin a VSS. Hobby RC type motors and motor controller (with a dead band adjustment) are possible sources for my parts.

dave w

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Originally Posted by KidTurbo

Here's one for those who like to swap modern EFI's into things that might not use a transmission, or way to feed the ECM a corrected Vehicle Speed Signal. In my case it was a boat, and I tested several of the latest GPS speedo converters out there. However the wave pattern was always wrong for my late model engine, so the ECM wouldn't recognize the pulse signal.

Then I found this GPS-50 from Dakota Digital

Has a built the built in GPS antenna, plus an accelerometer that kicks in if sat signal is lost. I've used one for 2 years now, mounted under a 1" thick fiberglass dash. Amazing little box that will pump out about any wave type or resolution you'll every need. Just one wire to the ECM VSS signal, 12v hot, ground, match up the pulses per mile and your done.

I don't work for them, or receive a dime from DD. Just like their stuff cause every time I've need some sort of special adapter, they say "we make that." And when ya like to DIY crazy builds like myself, it's cool to speak with someone who understands what your actually doing..

That's my tip of the day.

:thumbsup:

-K

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I've looked at those before but the price scared me away from testing! Thanks for the tip! Perfect solution! Although still a little pricy, when building a custom system I don't think the cost is prohibitive!

Dave W may have the cheap solution, especially when speed accuracy is not an issue.

:rockon:

I tried building a couple DIY analog style setups before finding this little unit. First was a hall effect paddle wheel setup specifically made for boat nav/depth units. Looked good on paper, but once connected a sine vs square wave signal issues kept if from working. Wasn't looking to build a wave converter on top of the wiring job, so scrapped that one. Next was a pressure based rig, also didn't play out well.

The biggest problem with any boat speedo is accuracy. Your standard old school marine speedo gauge units work off water pressure, or as above, a spinning wheel. Typically only accurate within 10-15% or so. New ones use a GPS to feed a dash speedo, but those wouldn't work with a ECM VSS either. The Dmax E60 ECM uses a high res 160k pulse per mile I believe, while some others GPS based units I testes were like 8 or 16k per mile. I could have adjusted the pulses with EFIlive, but once I found this piece and spoke to an engineer there who explained they built it to work with about any signal type ever used, I said ship me one and I'll let ya know. Within 20 minutes I had it wired in and ready to test.

What's also nice is it has a calibration mode that puts out a 60mph pulse signal for testing. When I compared it to a handheld GPS, it was within 2mph out of the box. I quick calibration in EFIlive and that puppy is spot on at any speed. I've refered a few LS engine swap guys to this unit also, they said it worked fine in their swaps too. Checked my setting in EFI;

{H0101} Vehicle Speed Sensor Pulses per Mile 127359.375000 Pulses/Mile
{H0102} Vehicle Speed Sensor Pulses per Revolution 40.000000 Pulses/Rev

$200 sounded pricy when I was doing this setup also, but after testing some cheaper ones, I can say it's worth every penny. Takes a thumping in the boat, high moisture local, and has done great. Battery drain was also a concern since it's always powered on. But it has a sleep mode built in and doesn't seem to have any noticeable drain when parked all winter...

Best,

-K

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Originally Posted by EagleMark

I've looked at those before but the price scared me away from testing! Thanks for the tip! Perfect solution! Although still a little pricy, when building a custom system I don't think the cost is prohibitive!

Dave W may have the cheap solution, especially when speed accuracy is not an issue.

:rockon:

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The marine application I've been thinking about is using TBI PCM 16197427, which is 2000 PPM. The DD does support 2000 PPM.:mad1: The TBI PCM does not need a VSS to be very accurate. The TBI PCM has near idle / off idle transition at about 3 MPH. I was thinking that the "plane" transition would be good place to switch from near idle / off idle fuel and spark tables.

dave w

That's kinda what got me on this project with the diesel. Needed the ECM to know when I was floating around "docking" or cruising down the river. Plus I have a couple J1939 CAN display units in the dash monitoring all the important pids, speed is up on there. Also allows ya calculate the MPG off the factory DIC settings. [Dmax averages about 5.5mpg in a 5000lb boat at 50mph]. And last, I'm thinking about adding some cruise control buttons to the steering wheel.
:wtg:

The LS1 guys I spoke with also needed to control off idle fuel and timing tables. Guess those run pretty crappy without knowing your moving..

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Originally Posted by KidTurbo

The LS1 guys I spoke with also needed to control off idle fuel and timing tables. Guess those run pretty crappy without knowing your moving..

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More then just the LS1 group! But without an E trans need for accuracy it's a lot easier to fudge moving and not moving.

Nice find, thanks for sharing the results! :thumbsup:

Cost is really nothing when considering doing these high end swaps/conversions.

that's a cool toy

but my eyes, in a marine application, gps speed isn't really an appropriate input for something like a VSS, especially in the salt or rivers in diverse conditions.

why? because of current.

think about it. gps is speed over ground, pitot tube or paddlewheel is speed over water.

example 1: you have a 5mph ocean current at your back. you're at dead idle in neutral. prop isn't moving. your 'gps vss' reads 5mph. a paddlewheel would read speed over water of ~0mph.

example 2: you are fighting a hell of a storm, head on into current, and some big rollers. you have this thing FLOORED trying to get home. you are NOT winning this battle. gps speed varies between -10mph and +2mph, despite your boat working its ass off and speed over water exceeding 30mph.

of course gps speed is the most useful metric for display speed in a boat since you equate it to travel time.

in the same token, gps speed is the shits for a rolling vehicle because it doesn't compensate for angle of hills (gps speed up a steep hill is as the crow flies, not as the car drives)

will it really matter? probably not, but on a boat i'd way rather have speed-over-water input for both datalogging and speed-related ecm parameters

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Originally Posted by steveo

of course gps speed is the most useful metric for display speed in a boat since you equate it to travel time.

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I'm all about speed... :geek:

http://www.youtube.com/watch?v=tvd-w7lk1Eo

Hauling butt, while also being about the "Greenest" thing out on the water has an added cool factor. If I could only find a totaled Tesla S for a good deal to play with, I'd step it up another notch.

Your point is a good one Steveo. In something like a larger boat where your making 10-15 knots having a true speed over water would make more sense. As far as reliability, I've also use DD tach adapter for the analog dash gauge for 4yrs now. Both units are mounted under the dash, but not sealed and exposed to moisture. Last month I tested the salt water impact by running 25 miles in heavy off shore chop. Everything in the boat had a coating of salt when I made it to the trailer.. I would defiantly seal that unit up if was in more of a "fishing boat" environment.

Just a little bit more chop in the water and you'd have had blown past 80! :jfj:

It's amazing how 80 MPH on water feels like twice that on land. Nice work, not much noise either! I like it! :thumbsup:

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Originally Posted by steveo

that's a cool toy

but my eyes, in a marine application, gps speed isn't really an appropriate input for something like a VSS, especially in the salt or rivers in diverse conditions.

why? because of current.

think about it. gps is speed over ground, pitot tube or paddlewheel is speed over water.

example 1: you have a 5mph ocean current at your back. you're at dead idle in neutral. prop isn't moving. your 'gps vss' reads 5mph. a paddlewheel would read speed over water of ~0mph.

example 2: you are fighting a hell of a storm, head on into current, and some big rollers. you have this thing FLOORED trying to get home. you are NOT winning this battle. gps speed varies between -10mph and +2mph, despite your boat working its ass off and speed over water exceeding 30mph.

of course gps speed is the most useful metric for display speed in a boat since you equate it to travel time.

in the same token, gps speed is the shits for a rolling vehicle because it doesn't compensate for angle of hills (gps speed up a steep hill is as the crow flies, not as the car drives)

will it really matter? probably not, but on a boat i'd way rather have speed-over-water input for both datalogging and speed-related ecm parameters

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This actually gave me more reason to not like these add-on GPS units for a typical conversion.

In the Datsun S30 world people are swarming to GPS based speedos, because it's "difficult" to create a proper VSS signal, and then calibrating, oh man that takes "forever". :facepalm:

My main problem with something like this is that any GPS unit I have used, personal navigation, smart phones, a couple laptop dongles all took a considerable amount of time to find satellites, even on clear days. There were days I would drive several miles before a good enough GPS signal was found. Now these were positioning based systems, but AFAIK the speed only based systems need the same 3 satellites minimum to provide an accurate speed. Even though I may not necessarily use my speedo as intended, I do like to know just what speed I am traveling at whenever the vehicle is moving. I can see overcast and story days being an issue as well. There are also areas where there are structures, like tunnels that could cause the signals to be lost.

I have yet to have any real issue re-creating a proper VSS input for an ECM or cruise control in several swaps, mechanically. Yeah it may have taken a while to sort out the wheels and sensor location but I know it works, and it's in-expensive to assemble.

Don't get me wrong, I do like the idea of a GPS speed sender, more as a back up, or being able to provide positioning data than just speed, but I just can't justify the prices I have seen and the known GPS issues I have experienced and read about other people experiencing. It's good to hear some positive reviews of something that works, for when the need arises.

you know, a GPS speed with a level sensor so it could figure out the whole 'going up a hill' issue could be a bit more accurate on a road vehicle, but afaik you're talking some law breaking stuff here too

a drivetrain driven speedo is legally required in every damn place i'm aware of; and pretty sure a functional odometer is too.

also...... 'sorry officer, i didn't think i was speeding! my gps signal died when i went under that bridge, and the accelerometer must have been thrown off by those pot holes!'

yeah right

I never took into consideration the GPS Satellite connection... yeah this is a major issue?

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Originally Posted by EagleMark

not much noise either! I like it! :thumbsup:

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What?! Sounds like an F-14 on a fly by :rockon:

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Originally Posted by brian617

What?! Sounds like an F-14 on a fly by :rockon:

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Wow, you just dated yourself ... the F14's were retired form service in 2006.

dave w

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Originally Posted by brian617

What?! Sounds like an F-14 on a fly by :rockon:

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LOL, that's a fairly common comparison I hear... The sound comes from a mix of straight cut gears in the out-drive, twin 4" exhaust outlets, and the turbo inlet being directly under that scoop on the hatch. Since everything faces to the back, it's actually pretty quiet inside the boat.

But I got a bright idea one day to turn that scoop around. Force more cool air into the engine bay. And by the end of the weekend, it was switched back....
:yikes:

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Originally Posted by EagleMark

I never took into consideration the GPS Satellite connection... yeah this is a major issue?

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Time to acquire a lock was a major concern for my VSS project. However one of the things I like about this manufacture, they seem to have some pretty smart engineers. The custom Harley crowd swears by their digital gauge clusters and speedometers. The engineers used two theories to overcome the normal acquisition delay and signal loss problems.

First, it attempts to never lose the GPS position lock. While part of the circuit sleeps when key is off, but the GPS chip is always kept active, so it has zero lag time on start up. A small red LED flashes every 30 seconds or so to show it's working.

Second, they added an accelerometer chip to the circuitry, and some pretty darn good logic to boot. If does lose the GPS signal, it switches over to the accelerometer for calculating speed data until GPS lock is recovered. Kinda like having a G-Tech unit built in.. Most modern factory automotive in-dash Nav units also employ this technique to deal with tunnels and such now. It knows you were last moving at XX mph, and if your speeding up or slowing down.

I had forgotten about it having the ignition switch connection in my post above. But also that it has cruise control capabilities built in. The manual for this thing is actually a "good read"

http://www.gearhead-efi.com/Fuel-Inj...7&d=1400978639

I mounted it under the dash where is has partial view of the sky. Next to my OBDII plug. The dash covering it is 3/4 plywood laminated with fiberglass and gelcoat. I'm amazed it works so well without a remote mounted antenna, or good line of sight.

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Originally Posted by dave w

Wow, you just dated yourself ... the F14's were retired form service in 2006.

dave w

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