My new aftermarket style D&D T56 will be coming with a T5 style Speedo hole in the housing. I need to get a standard LT1 type VSS signal (17 pulses per rev) to my LT1 PCM. It doesn't look like I can use a gear driven T5 type VSS sender because the total pulses per rev will be far below my ability to rescale with Tunercat. Was there ever a T5 Vss pickup that read directly off of a mainshaft mounted reluctor, or were they all speedo gear driven reluctors?

It looks like the 700R4 speedo hole is much larger than the T5 and a right angle style pickup has been used with the shaft mounted reluctor. That what most of the LT1 guys are using with the TH400 swaps.

Can anybody shed any light on this?? I guess I could always plug the T5 hole and remachine the tailhousing for the T56 VSS sender. Just seems like a pain!

Thanks
Steve

 

Put a normal T5 sender and a SGI 5 to up the signal

 

Thanks,

My OEM T56 with a 17 tooth reluctor, 4:11 gears. and a 26" tall tire produces about 54198 pulses per mile. If I am correct the T5 VSS produces 4000 pulses per mile with the correct speedo gearing. The SGI-5A can multiply the signal by 4X. That gets me to 16000 pulses per mile. I'm not sure I can scale up that far (X3.38) in the PCM. Now I might be able to regear the vss to output more than 4000PPM and use the SGI. Lets see, I'd need the largest driver and the smallest driven.

Thanks for your input

Steve

 

Maybe run 2 sgi5's in a row

 

Had another idea, put the gear sending unit in there from a 89 or earlier camaro, then use autometer sender 5291, it threads on there and is 16 pulse per rev, that should get you close enough after the gears inside to scale it correctly in the pcm.

Jegs PN on it is 105-5291

GM/Chrysler Sender, 7/8''- 18 Thread Hall Effect Sender | More Details $62.99 16-pulses per revolution. Includes pass-thru drive for cruise control

 

Might work! I'll check it out

Thanks,

Steve

 

With the 16 pulse per rev. sender you wouldnt even need to change the gears or anything because in Tunercat you can tell it how many pulses per rev the speed sensor is. I'm running into the same problem you are in trying to connect the speed sensor from a T-5 to the LT1 PCM. I wanted to try and do it without using the SGI-5 but I think I'm going to have to.

 

I ended up plugging the speedo hole in the tailhousing, welding a bung on and machining it for the correct VSS sender and replacing the mainshaft plastic gear with a reluctor.

Steve