DIY discussion - Increasing power to the G25 & G27 wheels

[mrsh 0]

great job !! Joker!!  i will get back the wheel & electronics later.

other question: can i change the gearing inside?  will this affect the calibration?

[TheJoker 0]

i dont think it would, because the max rotation of 900 degrees is limited by a rack at the bottom of the main gear. However, the gears are not straight as you can see in the pic and you will have a hard time finding one of these. Also keep in mind you would have to change the motor position (closer to the main gear).

[mrsh 0]

i mean just change the motor side gearing.

my thinking: 

1. plug in, calibration start: sys turn either left or right until hit the mechanical stop.

2. start to count the pulse generated by the encoder when it turn opposite side, again, til its hit the stop.

3. now sys had all the data: turn back half of the pulse counted--> centered

if G27 work like as above, put a gear box just before the big gear will make a great change in torque. i think the speed isnt important enough compare to torque.

[TheJoker 0]

i mean just change the motor side gearing.

??? You still need a gear which is inclined on the motor side as well. The rest is the same as what i am thinking, you might be right. But i think speed is very important, and the g25 speed is far too low, good drifting with street cars is impossible because the wheel centers too slow. But then again, if you only drive race cars with low rotation degrees changing the gears might make sense.

Anyways i am doing nice process on my button mod, if you like i could post some pics. Now i am only waiting for my carbon plate for the buttons.

[simul8r 114]

Joker, really appreciate your help but lets maintain this thread on the subject at hand which is, of course, tweaking the wheel.

[mrsh 0]

??? You still need a gear which is inclined on the motor side as well. The rest is the same as what i am thinking, you might be right. But i think speed is very important, and the g25 speed is far too low, good drifting with street cars is impossible because the wheel centers too slow. But then again, if you only drive race cars with low rotation degrees changing the gears might make sense.

Anyways i am doing nice process on my button mod, if you like i could post some pics. Now i am only waiting for my carbon plate for the buttons.

i think the slow turning speed at G25 is due to the lack of torque. If the torque is high enough, the speed can accelerate faster. i dont think the wheel can turn at  several  hundred rpm. even in a real case. i have a 540 motor with gear box turn at 2200rpm @DC24V and with torque: 5kg/cm. gear down once more by the original gear may have a speed around 200rpm with a torque close to 50kg/cm (assume the ratio 1:10)  what do u think?

[mrbasherman 41]

I haven't checked this myself, but I have read that the gear ratio in the G27 is 16:1.

 

The motors in the wheel, at 24 volts and max efficiency, unloaded, will turn at 1500 rpm. So if there were no gear train friction or anything else involved, the max rim rpm would be 93.75 rpm which is pretty quick.

 

However, it's not without friction of course... The motor datasheet states an rpm of 900 at "Max Power" which is probably a better assumption here. This yields a wheel speed of 56.25 rpm which sounds about right given what can be seen at startup, etc.

 

That said, a combination of a gear reduction and increase voltage could yield a bit of a "happy medium." However, I truly think trying to change the gearing around is going to require some major surgery on the wheel. You'd be better off stripping everything out of the wheel, making a new frame and using belts. (why nobody has done this, I have no idea)

[simul8r 114]

basher, you mentioned an idea earlier of replacing the mosfets to something stronger.  Did or do you have one in particular in mind?

[TheJoker 0]

i think the slow turning speed at G25 is due to the lack of torque.

I dont think so, when calibrating you can see the wheel instantly reaches the speed its supposed to get, there is basically no accelleration lag.

[simul8r 114]

 You'd be better off stripping everything out of the wheel, making a new frame and using belts. (why nobody has done this, I have no idea)

 

It has crossed my mind.  I've had thoughts of adding more motors on a bigger plate, even found helical gears on ebay.  Really need a spare wheel to experiment with, controller board and all.

[BrEaKnDiSh 24]

That said, a combination of a gear reduction and increase voltage could yield a bit of a "happy medium." However, I truly think trying to change the gearing around is going to require some major surgery on the wheel. You'd be better off stripping everything out of the wheel, making a new frame and using belts. (why nobody has done this, I have no idea)

 

Actually, they have: http://jlvrh.de/JL_Wheel_UK.htm

 

Interestingly they say their modified wheel - which uses a different gear ratio for stronger FFB - isn't recommended for rally games due to slower centering.

[mrsh 0]

I dont think so, when calibrating you can see the wheel instantly reaches the speed its supposed to get, there is basically no accelleration lag.

 

so increase the speed will help a lot. ([email protected]/cm) hope to get a good result

btw, can u estimate the rpm of the wheel?  60rpm? i need to get my wheel by next wk. thanks

[TheJoker 0]

sorry i got no idea, i would say about 80 rpm. What do you mean by saying you need to get your wheel by next wk.?

[simul8r 114]

Ok, hopefully to keep this discussion alive I recently received the 25vdc adapter from ebay (rated 25vdc @ 2.5amps).  It lacked the AC power cord which I fortunately found one in my collection of cords kept stashed in the garage.  The male part of the AC cord was kinda odd looking which I was lucky to have one that matched the adaptor's socket.  I performed a voltage check and found that it was putting out 26.5vdc and not 25 as labeled on the adaptor (see picture below).  Well, I could not resist my curiosity any longer and plugged her into my G27 fearing the worst.  I'm happy to say the wheel still lives but for how long I don't know.  Bottom line is, I'm enjoying that little extra torque I'm getting out of the wheel.  Prior to experimenting with the new adaptor I had my Logitech profile FFB settings set at 107% to at least obtain more 'bite'  with the stock adaptor (24vdc @ 1.75amps).  Since adding the 26.5vdc I had to lower that back down to 100% because the increasing amount of 'shimmies' had compounded even more.  My settings with Leo's FFB ini had to be adjusted as well and I also adjusted Rfactors ingame toe in/out settings and the results are quite obvious to say the least.  There was a little problem however with the shorter DC plug that went into the wheel which caused it to detach itself while in use.  I snipped that off and replaced it with a longer plug that I scavenged from my adaptor collection with no problem.  However, when I checked for power it revealed a drop of half a voltage to now 26vdc probably due to the longer cord I spliced.  So far the wheel seems to be operating better than before but I can't sense any more heat being generated within because, obviously, it's enclosed and the fans working.  The adaptor itself was a bit warm to the touch after some use but that also occurred to the stock adaptor I had before.

 

I'll report more if anything occurs while using the new adapter.

 

PS, for those of you who do happen read this and for some crazy reason decide to follow my lead please understand I take no responsibility for any damages you may cause to your Logitech wheel.  You do this at your own risk.

 

Also, aside from whatever experimentation I've conducted I hope this will continue with the discussion to achieve even more and of course proven safer increase power to the G25/27 wheel.

 

[TheJoker 0]

nice work

my stock g25 power supply is at 25 Volts, it comes down to 23.5 though when the wheel is turning. I am pretty sure though that a longer cable cannot affect voltage output.

[simul8r 114]

Thanks Joker but it was an assumption. How about providing yours if you think it wasn't the extra length of cord that didn't drop the voltage. I'd appreciate it.

[mrsh 0]

back. i hv got an idea. put a arcade machine FFB motor to the wheel. i found the motor use on most arcade is just a AC motor of some washing m/c.(just add a encoder) but at least one problem i mentioned b4: will the wheel be calibrate normally if i changed the gear ratio? the ratio is about 1:4-5 in the arcade (estimated by naked eye~) 

[simul8r 114]

back. i hv got an idea. put a arcade machine FFB motor to the wheel. i found the motor use on most arcade is just a AC motor of some washing m/c.(just add a encoder) but at least one problem i mentioned b4: will the wheel be calibrate normally if i changed the gear ratio? the ratio is about 1:4-5 in the arcade (estimated by naked eye~) 

 

You mean remove the 2 DC stock motors and replace them with the AC?  If you think it'll work then give it a try.  Some pictures would be great of what your planning.

[TheJoker 0]

Thanks Joker but it was an assumption. How about providing yours if you think it wasn't the extra length of cord that didn't drop the voltage. I'd appreciate it.

Heating up of electronic parts i guess (but still only an assumption as well)

[TheJoker 0]

will the wheel be calibrate normally if i changed the gear ratio?

You could try that by stopping the wheel when calibrating. Use e.g. a piece of wood to make the wheel stop at a certain angle left and right.

[mrsh 0]

You could try that by stopping the wheel when calibrating. Use e.g. a piece of wood to make the wheel stop at a certain angle left and right.

i just stop the wheel by hand, but  seems to abnormal calibration. it stopped for few second with the rpm light all on, then it calibrate again til calibration complete.

i will re-install the rack inside for doing the test.

[mrsh 0]

You mean remove the 2 DC stock motors and replace them with the AC?  If you think it'll work then give it a try.  Some pictures would be great of what your planning.

just need to know how the calibration work

found a wheel assembly of arcade machine

http://www.ebay.com/itm/SCUD-RACER-steering-shaft-motor-metal-frame-arcade-game-part-cf16-/161067217992?pt=LH_DefaultDomain_0&hash=item25805ab448

 

hacking of a logitech stick (i think it can also apply to wheel)

http://www.simprojects.nl/hacking_a_force_feedback_stick.htm

[mrsh 0]

just tested the calibration. result is........fail. it cant be calibrate when i stopped the wheel by blocking the gear rack. then re-calibrate 2 times more and stopped. 

i take the encoder and gear out. let do some calculation:

 

encoder: 60 pulse/rev.   

pinion: 11 teethes

spur: 180 teethes (not sure, it's a extremely hard work. anyone confirm?)

gear ratio: 1:16.36

so, the wheel go 2.5 turns --> motor: 40.9 turns --> pulse generated: 2454

by this calculation, test again. turn full right, then let the wheel turn about 2.5 turns backwards and force to stopped the wheel by hand. it calibrated !!

so i think the program must to be receive, say 2400-2500 pulse for a correct calibration. thus i cant change any gearing inside. in other words, keep the gear ratio is a must, after doing any modification.   

 

need more hard work..........

[Tberg 2]

Hi, anyone still at this?

I just started looking into it, and since I know a bit electronics I think it is possible to increase the power in the G25 diy. I just got an aftermarked wheel and miss a little speed in the wheel, so I took the G25 apart to have a look.

The two dual mosfets h-bridge driving the motors are rated +-60V @ 2,7A /25degree C. So, maybe they will handle 5-10V more no problem without reaching too high currents. I'm aware of the g25-e mod, as I can see it's just swapping those mosfets with some higher rated, change some resistors to adjust to the voltage from a bigger supply and the extra current the fets and motors are gonna draw.

Thinking of buying a cheap 30-50V regulated DC supply from parts-express and start testing. Already found N and P-channel mosfets at 80-100V, 10A, in TO220 housing, if the g25 originals are not gonna cut it.

All the Best

[simul8r 114]

Hi, anyone still at this?

I just started looking into it, and since I know a bit electronics I think it is possible to increase the power in the G25 diy. I just got an aftermarked wheel and miss a little speed in the wheel, so I took the G25 apart to have a look.

The two dual mosfets h-bridge driving the motors are rated +-60V @ 2,7A /25degree C. So, maybe they will handle 5-10V more no problem without reaching too high currents. I'm aware of the g25-e mod, as I can see it's just swapping those mosfets with some higher rated, change some resistors to adjust to the voltage from a bigger supply and the extra current the fets and motors are gonna draw.

Thinking of buying a cheap 30-50V regulated DC supply from parts-express and start testing. Already found N and P-channel mosfets at 80-100V, 10A, in TO220 housing, if the g25 originals are not gonna cut it.

All the Best

Hi tberg, actually the subject kinda went quiet but I would difinately be interested in your tests. Please provide us with your findings when able.