Hi Guys, I'm having problems with my race technology dash 2 (everyone seems to)
I've installed a hall effect sensor to do the wheel speed, working off the 4 diff-prop bolts.
The problem I'm having is the calculations them not displaying correctly. I think I've worked it out correctly as follows:
Tyres 195/50/50 = 1.80956m circumfrence
4 bolts on the prop
3.92 ratio diff
1609(rt figure)/1.8m = 889.1 x 4bolts = 3556 (which reads about 50mph at 10-15mph)
x 3.92 = 13942
Which is great (gave a roughly correct reading) but the dash only goes to 12000. Are my calculations correct and if so, am I going to have to move the
sensor? (push in diff btw so can't take it off the drive shaft bolts)
My other question is about the rpm sensor. I'm running a totally stock pinto, I know I can't take the tacho output from the coil to the dash
2 without damaging it. Is my only real option a hall effect sensor and a tigger wheel? or is there a more cost effective way of sorting it. This bit
is kind of holding me up from finishing my dash wiring.
I hope someone can help, you did last time.
Cheers, Steve
Intuitively shouldn't you divide by diff ratio?
That's what I first thought but I was doing 50mph pulling out of my garage so I guessed not!
Not going to help much but I picked up off the front right wheel using an abs sensor and mine is pretty much spot on... From memory it is about 3600
pulses I entered...
Probably worth mailing the guys at Race Technology to see if there is anything they can do or have.. I have found them very helpful.
quote:1609(rt figure)/1.8m = 889.1 x 4bolts = 3556 (which reads about 50mph at 10-15mph)
Originally posted by serieslandy
Hi Guys, I'm having problems with my race technology dash 2 (everyone seems to)
I've installed a hall effect sensor to do the wheel speed, working off the 4 diff-prop bolts.
The problem I'm having is the calculations them not displaying correctly. I think I've worked it out correctly as follows:
Tyres 195/50/50 = 1.80956m circumfrence
4 bolts on the prop
3.92 ratio diff
1609(rt figure)/1.8m = 889.1 x 4bolts = 3556 (which reads about 50mph at 10-15mph)
x 3.92 = 13942
Which is great (gave a roughly correct reading) but the dash only goes to 12000. Are my calculations correct and if so, am I going to have to move the sensor? (push in diff btw so can't take it off the drive shaft bolts)
My other question is about the rpm sensor. I'm running a totally stock pinto, I know I can't take the tacho output from the coil to the dash 2 without damaging it. Is my only real option a hall effect sensor and a tigger wheel? or is there a more cost effective way of sorting it. This bit is kind of holding me up from finishing my dash wiring.
I hope someone can help, you did last time.
Cheers, Steve
OK.....
1609meters in a mile/1.809m circumference = wheel revs per mile 889.44
(wheels revs per mile*diff ratio) = propshaft revs per mile
889.44 * 3.92 = 3486.6
propshaft revs per mile x 4 = 13946.4
Brain in a jar first time. Prop revolves 3.92 faster than the wheel .
You need to remove 2 of the magnets
[Edited on 6/12/13 by jeffw]
[Edited on 6/12/13 by jeffw]
I agree with your maths, obviously the prop is going faster than the wheel speed so you do indeed need to multiply by the diff ratio.
If there isn't a simple solution how about fitting tabs under two of the diff bolts and moving the sensor so that it only sees the tabs thus
halving the number of pulses.
Cheers
Davie
Beaten to it.
I would do what Davie suggests and add 2 tabs.
Get some repair washers and cut them to size and then make them 'L' shape.
Have fun.
Cheers guys. I like the simple solution. I'm guessing by repair washer you mean the same as penny washer?
quote:
Originally posted by jeffw
OK.....
1609meters in a mile/1.809m circumference = wheel revs per mile 889.44
(wheels revs per mile*diff ratio) = propshaft revs per mile
889.44 * 3.92 = 3486.6
propshaft revs per mile x 4 = 13946.4
Brain in a jar first time. Prop revolves 3.92 faster than the wheel .
You need to remove 2 of the magnets
[Edited on 6/12/13 by jeffw]
[Edited on 6/12/13 by jeffw]
Or move the sensor to the front disc....Don't Race Technology do a magnetic pick-up as well? I epoxyed a rare earth magnet to the inside of the rear wheel and ran the sensor next to that....worked fine.
I attached mine to the upright and picked up on the rear of the wheel studs... Works a treat....
Dave B
Dave, did you have the sensor at 90deg to the wheel studs or parallel?
Parallel... Can send you a picture if you want... Actually did me a favour at Iva because they didn't check the speedo I just had to prove I had it set up correctly. I am not saying this would be ok for all testers....
If you don't mind that wouldbe great. I'll be using Southampton as well so possibly the same guy.
O didn't see you were in Portsmouth... I'm only in Horndean...
[Edited on 7/12/13 by Dave Bailey]
It's a small world. I live in rowlands and work at keydell.
:-).... I'll pop over at some point... You can have a look....
How far are you off going to IVA?
Dave B
Not too far off iva. Aiming for early spring but have run out of money at the moment.
Of course if you use the wheel bolts you are 3.92 times lower so will easily get a figure that will work.
Cheers guys, I'm going to have at getting it to pick up only 2 prop bolts with the use of some washers, (around 6500 pulses). If that doesn't work I'll move it to the front upright.
Well I solved one problem and created another!
I installed 2 tabs on the prop bolts tonight and took the car for a spin. The dash was reading roughly the correct speed but when it got to 25mph just
stopped working.
I've put a post on the race tech forum but it seems kinda dead. Has anyone else seen a problem like this?
Do you mean it still reads but only up to 25 or it is dead completely?
It will do 1-24mph then nothing and picks up 24mph when you drop down again.
Just a guess but mabe the tabs are passing too quickly, mybe try making them wider and/or heavier so that the sensor sees them easily.
Cheers
Davie
That would seem sensible. Back to the drawing board again. They were only a bit of inch box cut into an L about 20mm wide. Probably not enough weight. Picking up the upright studs might be an easier option.
There is insufficient time between each pulse. I went through all this with the Koso Hall Effect and ended up using the rear wheel as is it 3.92 x slower than the prop. the further out you can back it the more time it has between each pulse.
First of all make sure the gap is small enough. I can't remember when I wired mine if the polarity mattered to make sure the rising edge was
clean...
Dave B
quote:
Originally posted by jeffw
There is insufficient time between each pulse. I went through all this with the Koso Hall Effect and ended up using the rear wheel as is it 3.92 x slower than the prop. the further out you can back it the more time it has between each pulse.
I think it's a combination of moving too fast and not a large enough mass to pickup the bit of metal. Gap is fine, between 1mm and about 3mm
tested with the led on the sensor when rotating the prop by hand.
A new bracket on the front upright is my best way forward I think.
Cheers for the help guys.
Putting it on the rear is easier
But I'm running drums
I have my pick up on the out put side of the diff [ drive shaft ] if this helps
I've had a look at the car tonight and I think it will be easier to Araldite a bolt head to the drive shaft (as they are push in shafts)
Would it be better for me to put 2 on the shaft so that it is a bit more balanced?
The other question is for the rpm, the lower cam pulley, it has 3 lobes that I can use as pickups for the hall effect sensor, my question is 6 pulses
(3 lobes + 2 rotations per rpm) going to be too many pulses?
quote:
Originally posted by serieslandy
I've had a look at the car tonight and I think it will be easier to Araldite a bolt head to the drive shaft (as they are push in shafts)
Would it be better for me to put 2 on the shaft so that it is a bit more balanced?
The other question is for the rpm, the lower cam pulley, it has 3 lobes that I can use as pickups for the hall effect sensor, my question is 6 pulses (3 lobes + 2 rotations per rpm) going to be too many pulses?
I've just realised I'm having a thick moment (been at work all day)
Its all to do with the size of the pulley for the number of rotations, nothing else.
doh
[Edited on 8/12/13 by serieslandy]
quote:
Originally posted by serieslandy
But I'm running drums
Steve.. sorry for the delay... If you go front wheel this is how I did it...
[img]
Wheels_sensor
[/img]
Thanks for the pic dave, how did you attach the bracket to the upright? Is it welded?
No the sensor has an m6 hole in the base.. I drilled through the upright and used a standoff to get the correct clearance to the wheel stud.
Dave B
I get you now Dave, I've got the bolt type sensor.
For RPM i'm sure we use the neg side of the coil, stright to the DL mk3 but before we had figured out the right settings on that, we had it going straight to the white wire on Dash2, but double check the instructions first just incase!
In the destructions it says that you cannot connect the high output (coil) to the dash2. You can connect the high to the dash2pro and dl1.
It's annoying as they have only just added that feature and I would have bought that one.
I have a DL1 for sale 