Someone told me there is a new mechanical speedometer drive that runs off vss signal to a drive motor on the back of your mech. speedometer but without the drive cable.Supposedly it will run gauges also.$150.Dont know the details.It was an ad in car craft but I can't find the issue.Anyone else see this or have any info on it?

 

That would be great!

 

If we're on the same page, check out Hawk's Third Generation web site. There is mechanical speedo to vss conversion parts there in the LS conversion section. It's not $150.00 though. Hope this helps.

 

No thats not it,thats like a cable x,the one I'm talking about mounts directly on the back of your mech. speedometer and eliminates the cable.I hope this is correct.I cant find the issue of car craft that has it,someone that has all the recent issues can look through them and see if they can find it.This is second hand info to me so I'm just hoping it's right.

 

I tried.

 

Let us know if you find it. What was on the cover?

 

I don't know,a friend of mine saw it and now can't find the issue.I will post up anything I find out about it,I sure hope he's right.Car craft has a lot about ls swaps and stuff here latley.May have to get a subscripton.

 

I'm not sure if this is the unit you are looking for. But i found this unit while looking for a cheaper solution. I just cant find anyone that's used it or any reviews at all.

http://www.dragonaero.com/SpeedChang...anicalPage.htm

 

I don`t remember seeing anything in car-craft, hot rod, or chevy high performance, I must have missed it.

I did look into the dragon aero one a bit, but IIRC you needed to buy a secondary electronic ratio adapter box that made it as expensive as the cable X. For the last few cars I did, I hid electronic speedo guts behind the stock face

 

How hard is electronic guts behind stock face?

 

I called the guy about the speedchanger mechanical last week. He told me about a year ago he would have it ready to ship in a month. Now he say it will ship when ready, no expected completion date. Also, he has raised the price on his website to $350, it used to be $125 if I recall correctly.

Sounds like an excellent product, time will tell. I am on the "waiting list" to be contacted when available.

 

Depends on the car and which speedo you pick. I used an autometer 120mph on the first car. On my el camino I had to redrill the mounting holes on the face and print out a new face (went from 85mph to 120 speedo) and then notch some of the inner dash structure.

since then I found that the late 80`s early 90`s GM trucks have an 85mph speedo that looks like it will bolt right to the back of the factory face. I have 2 different cars that I am going to try that on over the next couple months.

 

Same story that guy has been singing for at least 2 years, I contacted him about 2 years ago and it was always next week then next month, I think his set up was going to be similar to the cable x I wouldn't hold my breath waiting for his product.

 

Yes, I talked to him too.He said it was out of stock and put me on a list to call.It looks to be a great idea though,much better than the cable x to me .It has a small box that receives the vss signal that you can calabrate no matter what your gear ratio.This box in turn runs a small electric motor that screws directly on the back of your mechanical speedometer and spins it at the correct mph.It totaly eliminates the drive cable,sounds like a great idea to me if they get it done.According to him it will also run a factory tac as well.Looks like it would be an easier and better way to go than trying to run it through an org.speedometer cable.What about it ,any electronic gurus out there?Build it and make a ton of money!

 

I've never understood why those things are so expensive.

But I imagine if I ever tried to make one I would find out.

Can't be a big market so I'm sure that isn't helping.

 

Basicly its the same principal as the cable x only it eliminates the speedo drive cable and mounts directly on the mech.speedometer.It shouldn't need a very big or powerful electric motor when you eliminate the cable.Dosen't look like it would be too bad to build,of course thats easy for me to say isn't it.

 

Does anyone know the signal voltage the vss sends out? I've messed with the Arduino(google it) unit a bit on another project. I've all ready integrated it with a stepper motor that I can completely control through software. All I'd really need to do is interpret the vss signal and turn the stepper motor to the appropriate position. I could probably grab a stepper motor from a newer auto speedometer and control it. There would be a little fab work involved, but i think its very possible to DIY this one. I'll have to do some more research this weekend.

 

I am not sharp enough on electronics to do it but I am very interested if you can figure it out. I think many electronic speedos actually work like this.It would be a major help in the ls into/old car swaps if somone can figuer it out.

 

The VSS output from the PCM is a 4000 pulse per mile square wave signal. Not sure what the voltage is though.

 

It is a 0 to 5 volt square wave that varies the frequency with measured RPM.

The electronics wil be the relatively easy part. I think the challange will be sourcing a variable speed motor that is up to the job. Underdash also means it can't be too big.