Speedo After gearbox change
Discussion
Hello,
I need help to get the speedometer to work on my Griffith 400 pre-cat following the replacement of the gearbox by a T5 (Tuscan type)
We tried with a sensor from a Griffith 500 (also T5) without success.
I read here someone talking about an emulator that cars with lt77 would not have!
Thanks
I need help to get the speedometer to work on my Griffith 400 pre-cat following the replacement of the gearbox by a T5 (Tuscan type)
We tried with a sensor from a Griffith 500 (also T5) without success.
I read here someone talking about an emulator that cars with lt77 would not have!
Thanks
would a signal converter help?
https://www.dakotadigital.com/index.cfm/page/ptype...
(SGI-100BT: Universal Speedometer and Tachometer Interface)
I replaced my LT77 (92 Griffith) with a different gearbox, I now use a toothed wheel and sensor into the Dakota converter, then out to the speedo, works a treat.
hope it's of some help
https://www.dakotadigital.com/index.cfm/page/ptype...
(SGI-100BT: Universal Speedometer and Tachometer Interface)
I replaced my LT77 (92 Griffith) with a different gearbox, I now use a toothed wheel and sensor into the Dakota converter, then out to the speedo, works a treat.
hope it's of some help
Edited by Pagey430 on Tuesday 25th April 12:50
Pagey430 said:
would a signal converter help?
https://www.dakotadigital.com/index.cfm/page/ptype...
(SGI-100BT: Universal Speedometer and Tachometer Interface)
I replaced my LT77 (92 Griffith) with a different gearbox, I now use a toothed wheel and sensor into the Dakota converter, then out to the speedo, works a treat.
hope it's of some help
Thank you, this could be a good solution.https://www.dakotadigital.com/index.cfm/page/ptype...
(SGI-100BT: Universal Speedometer and Tachometer Interface)
I replaced my LT77 (92 Griffith) with a different gearbox, I now use a toothed wheel and sensor into the Dakota converter, then out to the speedo, works a treat.
hope it's of some help
Edited by Pagey430 on Tuesday 25th April 12:50
What sensor did you use?
can't find the receipt but I'm sure it was one of these...
https://www.demon-tweeks.com/race-technology-data-...
https://www.demon-tweeks.com/race-technology-data-...
Pagey430 said:
can't find the receipt but I'm sure it was one of these...
https://www.demon-tweeks.com/race-technology-data-...
Ok, thank youhttps://www.demon-tweeks.com/race-technology-data-...
It’s something to do with the pulses per revolution. The sensor that the 500 uses isn’t the issue, it’s the castellated ring and how many cutouts it uses to provide the correct pulses…..I think.
If you know the pulses for the LT77 gearbox I would assume you need something the same to run off the prop as per the Griff 500.
If you know the pulses for the LT77 gearbox I would assume you need something the same to run off the prop as per the Griff 500.
Christian
T5's are worth the effort, they are more robust, reliable & the gear changes can be much faster and harder especially with the S10/Tuscan rear housing.
RobXjcoupe is right, the 16 tooth castellated ring will produce too may pulses for the Precat speedo and the 14CUX plus the 500 sensor signal is too weak as its only a very basic coil.
My son has Pagey430 sensor with 4 pulses on the prop-shaft and works perfectly with the 14CUX and in theory should work with the Precat speedo but the calibration will never be spot on, therefore Christian's "SGI-100BT: Universal Speedometer and Tachometer Interface" sounds like a good idea.
Griff Precat Speedos are notoriously unreliable and mine was broken when I bought my Griff, therefore I bought a programmable speedo & sensor from SpeedyCables which they printed a TVR look a like face for it. You can see my speedo near the bottom of this page
https://www.pistonheads.com/gassing/topic.asp?h=0&...
(Tuesday 7th September 2010) & I was the original purchaser back in 2007.
Its an upside down Caerbont’s Electronic Programmable Speedometer in disguise" and still working perfectly 15 years on.
https://www.caigauge.com/documents//product-instru...
I had this castellated wheel made which works with the 14CUX and should work with the Precat Speedo, the other sensor is for my E-PAS.
Another approach if you're an electronics wiz-kid, you could copy Colin's home made speedo interface.
https://www.pistonheads.com/gassing/topic.asp?h=0&...
cmb on Wednesday 25th June 2014.
Please let use know how it goes as this is a common problem especially as the LT77's sensors are unreliable and un-repairable.
T5's are worth the effort, they are more robust, reliable & the gear changes can be much faster and harder especially with the S10/Tuscan rear housing.
RobXjcoupe is right, the 16 tooth castellated ring will produce too may pulses for the Precat speedo and the 14CUX plus the 500 sensor signal is too weak as its only a very basic coil.
My son has Pagey430 sensor with 4 pulses on the prop-shaft and works perfectly with the 14CUX and in theory should work with the Precat speedo but the calibration will never be spot on, therefore Christian's "SGI-100BT: Universal Speedometer and Tachometer Interface" sounds like a good idea.
Griff Precat Speedos are notoriously unreliable and mine was broken when I bought my Griff, therefore I bought a programmable speedo & sensor from SpeedyCables which they printed a TVR look a like face for it. You can see my speedo near the bottom of this page
https://www.pistonheads.com/gassing/topic.asp?h=0&...
(Tuesday 7th September 2010) & I was the original purchaser back in 2007.
Its an upside down Caerbont’s Electronic Programmable Speedometer in disguise" and still working perfectly 15 years on.
https://www.caigauge.com/documents//product-instru...
I had this castellated wheel made which works with the 14CUX and should work with the Precat Speedo, the other sensor is for my E-PAS.
Another approach if you're an electronics wiz-kid, you could copy Colin's home made speedo interface.
https://www.pistonheads.com/gassing/topic.asp?h=0&...
cmb on Wednesday 25th June 2014.
Please let use know how it goes as this is a common problem especially as the LT77's sensors are unreliable and un-repairable.
stevesprint said:
Christian
T5's are worth the effort, they are more robust, reliable & the gear changes can be much faster and harder especially with the S10/Tuscan rear housing.
RobXjcoupe is right, the 16 tooth castellated ring will produce too may pulses for the Precat speedo and the 14CUX plus the 500 sensor signal is too weak as its only a very basic coil.
My son has Pagey430 sensor with 4 pulses on the prop-shaft and works perfectly with the 14CUX and in theory should work with the Precat speedo but the calibration will never be spot on, therefore Christian's "SGI-100BT: Universal Speedometer and Tachometer Interface" sounds like a good idea.
Griff Precat Speedos are notoriously unreliable and mine was broken when I bought my Griff, therefore I bought a programmable speedo & sensor from SpeedyCables which they printed a TVR look a like face for it. You can see my speedo near the bottom of this page
https://www.pistonheads.com/gassing/topic.asp?h=0&...
(Tuesday 7th September 2010) & I was the original purchaser back in 2007.
Its an upside down Caerbont’s Electronic Programmable Speedometer in disguise" and still working perfectly 15 years on.
https://www.caigauge.com/documents//product-instru...
I had this castellated wheel made which works with the 14CUX and should work with the Precat Speedo, the other sensor is for my E-PAS.
Another approach if you're an electronics wiz-kid, you could copy Colin's home made speedo interface.
https://www.pistonheads.com/gassing/topic.asp?h=0&...
cmb on Wednesday 25th June 2014.
Please let use know how it goes as this is a common problem especially as the LT77's sensors are unreliable and un-repairable.
Hi Steve and thanks for replying!;)T5's are worth the effort, they are more robust, reliable & the gear changes can be much faster and harder especially with the S10/Tuscan rear housing.
RobXjcoupe is right, the 16 tooth castellated ring will produce too may pulses for the Precat speedo and the 14CUX plus the 500 sensor signal is too weak as its only a very basic coil.
My son has Pagey430 sensor with 4 pulses on the prop-shaft and works perfectly with the 14CUX and in theory should work with the Precat speedo but the calibration will never be spot on, therefore Christian's "SGI-100BT: Universal Speedometer and Tachometer Interface" sounds like a good idea.
Griff Precat Speedos are notoriously unreliable and mine was broken when I bought my Griff, therefore I bought a programmable speedo & sensor from SpeedyCables which they printed a TVR look a like face for it. You can see my speedo near the bottom of this page
https://www.pistonheads.com/gassing/topic.asp?h=0&...
(Tuesday 7th September 2010) & I was the original purchaser back in 2007.
Its an upside down Caerbont’s Electronic Programmable Speedometer in disguise" and still working perfectly 15 years on.
https://www.caigauge.com/documents//product-instru...
I had this castellated wheel made which works with the 14CUX and should work with the Precat Speedo, the other sensor is for my E-PAS.
Another approach if you're an electronics wiz-kid, you could copy Colin's home made speedo interface.
https://www.pistonheads.com/gassing/topic.asp?h=0&...
cmb on Wednesday 25th June 2014.
Please let use know how it goes as this is a common problem especially as the LT77's sensors are unreliable and un-repairable.
(I had sent you a message also through the forum )
I have contacted Speedy Cables, they are charging me £320 to change my meter!
At the moment I would like to find a cheaper solution!
Is the SpeedyCables sensor also suitable? (here https://www.speedycables.com/accessories-senders/ )
Can you explain what the "Z80081-MO631 Perception Head: TVR Compatible" is?
I'm thinking of starting with this solution and then see if the
SGI-100BT is necessary.
Thank you.
Christian
Edited by Christian Dauger on Thursday 27th April 10:38
Edited by Christian Dauger on Thursday 27th April 12:47
Christian Dauger said:
Yes, that would be interesting!
Even 2 if possible!
I hope stevesprint can give some dimensions...
Let it with me, I'll sort something over the weekend.Even 2 if possible!
I hope stevesprint can give some dimensions...
In theory the Precat speedo should work with Race Technology's sensor but may not be very accurate. You may need 3 or 4 pulses on the propshaft so only make 1 to try, there are two variable resistors in a Precat speedo which hopefully adjust the calibration & will be very interesting to find out.
Christian
I’m no professional and measured the best I can by hand with digital calipers so please let me know if anything doesn’t add up or you need further measurements.
I suggest you start with 3 or 4 teeth and make their width the same size as the gaps.
The bolt holes are spaced differently and difficult to measure accurately, so maybe worth increasing the holes to 10.0mm as they could be out a fraction of a mm and require hand filing to fit. Alternatively, as you’ve tried a Griffith 500 sensor, it would be best if you post yours to Rob to copy.
Please note this is for a Precat GKN diff, the BTR flange maybe different.
Good Luck
Steve
I’m no professional and measured the best I can by hand with digital calipers so please let me know if anything doesn’t add up or you need further measurements.
I suggest you start with 3 or 4 teeth and make their width the same size as the gaps.
The bolt holes are spaced differently and difficult to measure accurately, so maybe worth increasing the holes to 10.0mm as they could be out a fraction of a mm and require hand filing to fit. Alternatively, as you’ve tried a Griffith 500 sensor, it would be best if you post yours to Rob to copy.
Please note this is for a Precat GKN diff, the BTR flange maybe different.
Good Luck
Steve
stevesprint said:
Christian
I’m no professional and measured the best I can by hand with digital calipers so please let me know if anything doesn’t add up or you need further measurements.
I suggest you start with 3 or 4 teeth and make their width the same size as the gaps.
The bolt holes are spaced differently and difficult to measure accurately, so maybe worth increasing the holes to 10.0mm as they could be out a fraction of a mm and require hand filing to fit. Alternatively, as you’ve tried a Griffith 500 sensor, it would be best if you post yours to Rob to copy.
Please note this is for a Precat GKN diff, the BTR flange maybe different.
Good Luck
Steve
Thank you very much SteveI’m no professional and measured the best I can by hand with digital calipers so please let me know if anything doesn’t add up or you need further measurements.
I suggest you start with 3 or 4 teeth and make their width the same size as the gaps.
The bolt holes are spaced differently and difficult to measure accurately, so maybe worth increasing the holes to 10.0mm as they could be out a fraction of a mm and require hand filing to fit. Alternatively, as you’ve tried a Griffith 500 sensor, it would be best if you post yours to Rob to copy.
Please note this is for a Precat GKN diff, the BTR flange maybe different.
Good Luck
Steve
OP I guess you've already done this but it maybe worth checking your speedometer unit for either 8 or 4 pulse working? This can be done by verifying the original transducer part number: https://www.racetechdirect.co.uk/car-parts/electri...
Also: https://www.pistonheads.com/gassing/topic.asp?h=0&...
Also: https://www.pistonheads.com/gassing/topic.asp?h=0&...
Mine is done off pulses off the drive shaft, with a new speedo.
Could not get the original speedo to work with T5 box, and few clever people (cleverer then me any way) looked at it for me and couldn't get it to work so had to have a new speedo that works off the drive shaft.
When a group buy was done for pre cat lookey likey I got one of them to give the pre cat look.
I still have the speedo that works of pulses on the drive shaft if any one interested.... I found it the other month under the stairs and had forgotten I had it....can post pics if anyone interested.
Hoover
Could not get the original speedo to work with T5 box, and few clever people (cleverer then me any way) looked at it for me and couldn't get it to work so had to have a new speedo that works off the drive shaft.
When a group buy was done for pre cat lookey likey I got one of them to give the pre cat look.
I still have the speedo that works of pulses on the drive shaft if any one interested.... I found it the other month under the stairs and had forgotten I had it....can post pics if anyone interested.
Hoover
Edited by Hoover. on Thursday 4th May 17:00
Hoover. said:
Mine is done off pulses off the drive shaft, with a new speedo.
Could not get the original speedo to work with T5 box, and few clever people (cleverer then me any way) looked at it for me and couldn't get it to work so had to have a new speedo that works off the drive shaft.
When a group buy was done for pre cat lookey likey I got one of them to give the pre cat look.
I still have the speedo that works of pulses on the drive shaft if any one interested.... I found it the other month under the stairs and had forgotten I had it....can post pics if anyone interested.
Hoover
We'll try it already with the sensor indicated by Pagey430 and a provisional setup to test the number of pulses. I hope it will work, but just in case,Could not get the original speedo to work with T5 box, and few clever people (cleverer then me any way) looked at it for me and couldn't get it to work so had to have a new speedo that works off the drive shaft.
When a group buy was done for pre cat lookey likey I got one of them to give the pre cat look.
I still have the speedo that works of pulses on the drive shaft if any one interested.... I found it the other month under the stairs and had forgotten I had it....can post pics if anyone interested.
Hoover
Edited by Hoover. on Thursday 4th May 17:00
I'd like some pictures and what price would you charge for them? Is it the one modified by SpeedyCables that you have?
Thanks
Christian Dauger said:
I'd like some pictures and what price would you charge for them? Is it the one modified by SpeedyCables that you have?
Thanks
Christian.. apologies for late reply as do not come here regularly these days...... I will have to relocate the speedo.....at least I know its' vicinity, TBH I forgot I had it and when I found the box I had no idea what was in it.Thanks
Yes it was modified by Speedy Cables and IIRC it as constructed using my old speedo housing so will fit the dash hole , 500 speedos I believe are bigger - I will take some measurements just in case.
Christian
How are you getting on?
I've just spotted SpeedyCables have added to their website the Speedo they made for me 15 years ago, probably as its a common fault. The lack of price is a worry but it's calibration is programmable plus its been faultless.
https://www.smiths-instruments.co.uk/tvr/series-4
How are you getting on?
I've just spotted SpeedyCables have added to their website the Speedo they made for me 15 years ago, probably as its a common fault. The lack of price is a worry but it's calibration is programmable plus its been faultless.
https://www.smiths-instruments.co.uk/tvr/series-4
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