69MyWay

iTrader: (2)

Anybody running a LS or other late model engine combo figure out how to attach a VSS (vehicle speed sensor) to your old school Muncie...or ROD 5/6 that is compatible with the LS computer?

The auto trans with 4L6oE requires the VSS to shift...etc, and is a no-brainer because they come stock from the donar car with the right singal.

However, I'm building a DBW LS style system with a ROD6 (same rear gear set up as an old Muncie) and want the cruise control to work...as well as let the engine know how fast it is going...etc.

I looked at the Dakota Digital conversion - but it only gets 8K pulse out...and even with a multiplier box...it can't get anywhere near the 128K pulse required for the LS application.

I saw a Jagsthatrun.com reluctor wheel speedo kit that bolts to the diff input yoke for a S-10 to do the trick on those vehicles.

Anything for the older trans that can go in the tail housing and shaft and work? Has to be...as I assume the guys running TH400 behind Late model F bodies still have a speedo - perhaps the housing/output is the same????

Bowtie70SS

iTrader: (10)

THM 400 can use this http://www.am-autoparts.com/AM/Senso...ogle_base_feed speed sensor. Ufortunately the Muncie has the same speedometer housing as a THM350. I don't see why you couldn't use the reluctor wheel from a 4L60 or 4l80 depending on the output shaft diameter (2 for muncie). Maybe you could do a 4l60 reluctor wheel and a Ford or other style speed sensor that will fit in the tailshaft. Is your speedometer on the drivers' or passenger side? If it is on the drivers' side good luck that will be a whole lot going on with the shift linkage and all.

69MyWay

iTrader: (2)

Very good information.

The output is on the passenger side.

I didn't realize the TH400 and TH350 had different speedo out-puts, never paid attention before.

There is a local trans shop that might let me borrow a couple of different reluctors and see what it would take to get on the shaft.

I wonder what the airgap has to be between wheel and sensor tip.

poconojoe

iTrader: (43)

Way do you think, you need 128,000 pulses to drive the LS1 computer? Are you talking per mile mile or what? Factory set ups do not have any where near that number of pulses per revolution. The speedometer output is 4K per mile, the only thing high speed is the ABS signal. If your only using it for cruse control, it doesn't even have to be acturate. When you activate the CC, it just maintains the vehicle at the same number of vss pulses.

By the way in the mid to late 80 since the P series vans (Bread Trucks) had mechanical speedomters, they have an adapter that screwed on to the speedometer output on the tranny to supply the VSS pulses and the speedometer cable screwed on to it

69MyWay

iTrader: (2)

You make a great point - and I have thought the same thing. I was talking to Dakota Digital about the pulse amount - etc, I believe the 128K is average or so per mile. I thought the computer required this as an imput- and puts out the 4K to the gauge...maybe I'm wrong.

I primarly want this for the dbw cruise to work. Since it is a manual shift - I don't know what if any differene there will be in overall running if it does/doesn't have an accurate speed input. I want it to run as smooth and efficient as possible.

downset71

not to hi-jack thread, but does anybody know the inner and outer dimensions of a T-56 reluctor?

69MyWay

iTrader: (2)

By the way, does anybody know if this is suppose to feed through a convential style gear to gear action (appears in the picture no gear on the transmission input end of this unit) - then convert that out to a electronic signal?

I also then assume this won't fit the TH350/Muncie style housing....

69MyWay

iTrader: (2)

Actually, I'm more confused then. The one from Dakota that WILL fit my trans is a 8K PPM.



Now...I do know in my 69 Camaro that has a LS1 and 4L60E trans...when I calibrate my speedo (Autometer Ultra Lite electric feed), it hits 120,000+ on the screen in a mile or so.

Anyway...so what is it? Does the stock LS/LQ system feed a 8,000 PPM or the higher number?

If it is 8K - I'm golden with this unit - if more...I need to retro something in there.

poconojoe

iTrader: (43)

How do you know it's 8K per mile, since the plastic gears in the tranny control how fast the speedometer cable turns?

downset71

calibrated mine today. about 48,000 pulses with a 700r4,3.55s, and 275/45 18s if its any help( have a 40ppr ring )

69MyWay

iTrader: (2)

Can you help me out with that a little more?

I am hearing now two different stories.

1. The output needed from the VSS is 4K PPM

If this is th case, i can get the 8K sensor noted above and use a box to cut it.

2. The output needed has to come from a 40 tooth reluctor that when rolled out over the mile turns about 128K

Then...I hear you may be able to edit the program to accept a different amount - such as 8K.

Can you shed some light on how you did that?

downset71

might have to give me a few days to double check that number..i blew an airbag sunday will post asap with my result

69MyWay

iTrader: (2)

Hey brothers...still working this out, and by changing my search terms I found a little more info.

HOWEVER, I found out today that since my Richmond 6 uses the Turbo 400 Yoke - the output shaft is the same as a Turbo 400. In fact, I stopped by a trans shop with a ROD 6 spilled out on the table and held it in my hand and confirmed. It is splined all the way.

So.....does anybody know what 40 tooth reluctor would fit a TH400...and if so, I think I can drill the housing to drop a sensor right on top - then set it in place. I would still have the complete gear driven assembly possibly (depending on space) for running an old school speedo, or just plug it off.

downset71 - MAN...that blows (no pun intended) with the airbag!

Also - talked to my tuner today about editing the PCM to accept the 8,000 PPM sensor signal that I know I can generate off the Dakota adapter - waiting on confirmation there too.

Bowtie70SS

iTrader: (10)

The THM400 and a 4L80 have the same diameter output shaft, as for the tooth count I don't know. If you have a mechanical speedo there are many different drive/driven gear combos and they are identified by color.

topher455

iTrader: (6)

Older 82-87 g and b bodies with a feedback q-jet had a vss box behind the cluster that converted the analog movement of the speedo cable into a digital signal. Also 90's chevy cargo vans with a th400 had a vss on them that was gear driven. I dont know the pulses per mile but I was able to calibrate it to my autometer digital speedo.

LS1MCSS

iTrader: (18)

That's only a two pulse per rev output on the g-body sensor. Look at a speed sensor for a 4WD truck that was mounted in the transfer case. If you can get a reluctor that will fit the TH400 output shaft you might be able to mod the sensor to fit your tranny. The sensor won't determine the number of pulses. The reluctor will do that. The sensor will just count the number of teeth as they go by.
JagsThatRun also sells a 4 pulse per rev sensor that will screw onto a GM speedo cable mount.

topher455

iTrader: (6)

Oh well it was worth a shot. Things like this make me glad I have a CARB!!!

69MyWay

iTrader: (2)

New plan...what do you guys think? My thought here is to get the 4L80E since I have the 32 spline th400 slip yoke and size output shaft. If I can get a reluctor on here...then perhaps I can drill through the case to set the sensor.

Okay..here is a shot of the speedo hole access on the ROD 6 - I have slid the rear cover off exposing the position of the plastic gear locatoin.



This picture is to show that the gear is directly behind the hole - but it is off to make the stock connection at 90 for the driven gear. However, there is ample material below it to drill and insert a standard VSS sensor (4L80E)



Here is an idea of exactly where it sits on the shaft (32 spline)



This gear isn't centered here, but it gives you and idea of how much room there is in the housing at just about the exact location on the shaft:



And this shows the size of the hole at the most narrow section.

69MyWay

iTrader: (2)

Here is some good stuff. The GM reluctor wheel 8655315 pictured below on a Turbo 400 with the 32 spline shaft (same as mine). However, I'm splined all the way...it isn't. I think I can use some sort of groove and roll pin to lock it in place as the diameter should be right on. Because I don't have space in the case to put the big sensor, going to try to run the standard little tater tot sensor as seen on the 4L60E.

Thoughts?

itslow

iTrader: (4)

Do you need to keep a mechanical output to drive a mechanical speedometer?

You shouldn't need to go mucking around inside the transmission adding reluctors that weren't there originally. Sensors are readily available with a variety of signal outputs (4 pulses per rotation, 8 PPR, 16 PPR, 40 PPR) that attach to the mechanical output of the transmission, some with pass-throughs that retain the mechanical output, if needed. From that I think all you'd need to do is tweak the appropriate parameters in the PCM to correct for the input; changing the gears for the transmission's mechanical speedo output may be required for any differential gear or tire size changes to get your PCM parameters closer to actual.

For example, check the website of "Magnetic Sensors Corporation". Jags that Run has some on it's "Cable-driven speed sensors" page, too. A more in-depth search or inquiry should turn up more.

John @ Speartech has some older posts on here that can help give a little more insight as to what may be needed. I also saw one where he recommends using a non-LS1 cruise control module.