825 replies to this topic

[speedengineer]

I figure that welding the shaft is part of the process of de-powering the rack, it's a common operation.  That torsion bar is a critical component to the operation of the power steering system; without it the system would not operate. 

 

That said, I went and re-read the section in the GCR and the wording wasn't quite as I remember.  It actually says:  "Manual or power steering racks may be used. Power steering racks may be converted to manual by removing all power steering components."  While that wording isn't what I thought, it also makes every depowered rack running in an SM today illegal, by the strict letter of the rule:  If you can only convert them by removing all of the power steering components, then you would have to remove the torsion bar too as it is power steering component.  If that's removed, then the steering rack wouldn't even be connected!  So, certainly some grey area here.

 

But I'm curious to hear some other opinions.  I thought this was a very common practice for Spec Miata, am I wrong?  Thoughts from others?  Hoping I don't have to go buy another rack lolol 

[dstevens]

I didn't need to weld anything when I de-powered the NA steering rack.  I used plugs from Wheeler.

Dollars to donuts welding inside the rack doesn't conform to the regs.

[Dave D.]

Is there really a difference between welded and not that can be felt? Has anyone driven back to back welded and non welded pinion cars? For all the racks I have de-powered, I did not weld and when installed in my own car did not feel any real slop. I was  always nervous about welding a spring steel( the torsion bar) and creating micro cracks in a critical steering piece.

[speedengineer]

Is there really a difference between welded and not that can be felt? Has anyone driven back to back welded and non welded pinion cars? For all the racks I have de-powered, I did not weld and when installed in my own car did not feel any real slop. I was  always nervous about welding a spring steel( the torsion bar) and creating micro cracks in a critical steering piece.

Well it's sounding like I'll be having to buy another rack if this isn't a standard practice for SM. 

 

http://forum.miata.n...ad.php?t=335874
Interesting read, someone measured the steering compliance before and after.  I have never driven a non-welded depowered rack on a race track, actually.  That said, you can feel it some compliance when the car is parked.  It's not 'loose' slop, it's compliance, as it takes some force to comply. 


I haven't fully taken one of these apart to be sure, but it appears that you are not welding on the torsion bar itself.  This is a very common modification for miata race cars, even if it isn't for SM.  I myself have never heard of one breaking.  Zero issues with my old car.  I still doubt that a decent percentage of SM's aren't running around with welded steering shafts...
 

[Michael Novak]

Well it's sounding like I'll be having to buy another rack if this isn't a standard practice for SM. 

 

http://forum.miata.n...ad.php?t=335874
Interesting read, someone measured the steering compliance before and after.  I have never driven a non-welded depowered rack on a race track, actually.  That said, you can feel it some compliance when the car is parked.  It's not 'loose' slop, it's compliance, as it takes some force to comply. 


I haven't fully taken one of these apart to be sure, but it appears that you are not welding on the torsion bar itself.  This is a very common modification for miata race cars, even if it isn't for SM.  I myself have never heard of one breaking.  Zero issues with my old car.  I still doubt that a decent percentage of SM's aren't running around with welded steering shafts...
 

Mountain out of a molehill!!!!   Use Wheelers plugs---turn the rack both ways about 10 times and install plugs and done......    It works perfectly and easily....

[speedengineer]

Mountain out of a molehill!!!!   Use Wheelers plugs---turn the rack both ways about 10 times and install plugs and done......    It works perfectly and easily....

You know I like to make things difficult Mike!  I'm sure that way works perfectly fine.  Really though, my way was maybe two hours start to finish.  And it's more fun.  And now I get to do it again    Actually, I suppose I could just swap out the pinion shaft and not even have to take the rack apart again.

[38bfast]

Jason just leave the dam thing alone and move on to stuff that maters.

[Dave D.]

I'm with Jason, I prefer to get the piston and seals out of there and reduce the drag. I had a  GT car with a manual rack as well as formula and sports racers. I would think with a solid heim suspension there COULD be a difference in feel. However I would also think with the Miata's rubber-jointed street car suspension, any "compliance" or slop felt most likely would be there and not from the rack.

[LarryKing]

 

turn the rack both ways about 10 times and install plugs and done......

 

Mike omitted a critical step...  spray hydraulic fluid to the four corners of your shop and done......

 

FWIW I prefer the 'feel' of a manual rack, which also weighs less than the power rack. You can probably pick one up at a salvage yard for a song. Anyone know any Miata junkyards?

[Dave D.]

A manual rack for an NB is a rare piece. I think they only came on a special "sport" model. Plus the power rack is a slightly quicker ratio that many prefer on track.

[chris haldeman]

Nb manual racks are not very common. I usually have too buy them new for customers wanting one. Price is 750ish

[Michael Novak]

I have the manual rack in both of our cars and a spare..  I like the feel of the manual rack but I don't think the difference is night and day. I will say not touching the inside of the powered rack was something that I tried to do. There are a ton of ways to crash and possibly having something come apart that I caused by Fing with it seemed like a good thing not to do...

[speedengineer]

Mike omitted a critical step...  spray hydraulic fluid to the four corners of your shop and done......

 

Ha, yup

 

A manual rack for an NB is a rare piece. I think they only came on a special "sport" model. Plus the power rack is a slightly quicker ratio that many prefer on track.

I do like the fast ratio, wouldn't want any slower than it is for most tracks, and I even use a small diameter 330mm wheel.  I do think there are some tracks with high speed corners that would benefit from the precise, slow turn in that the manual rack ratio helps with.

 

Nb manual racks are not very common. I usually have too buy them new for customers wanting one. Price is 750ish

Yikes!  Out of my price range for this build. 

 

I have the manual rack in both of our cars and a spare..  I like the feel of the manual rack but I don't think the difference is night and day. I will say not touching the inside of the powered rack was something that I tried to do. There are a ton of ways to crash and possibly having something come apart that I caused by Fing with it seemed like a good thing not to do...

Even if not modifying anything on the inside, it's still a good idea to take apart and inspect a 15 year old 100k mile oem rack.  Then properly re-grease the rack and the inner tie rod ends, then reassemble. 

[davew]

I may be biased, but my opinion, based on over 200 builds, is to buy the 2 plugs that I sell. Spend 10 minutes installing them (plus an hour of cleanup  ) then forget about it.

 

Every rack that I have ever seen go bad has been from someone disassembling it and not getting it reassembled properly. I am not saying it can't be done properly.

 

I have never seen a high mileage rack and pinion fail under race conditions. Unless there was contact with another object.

 

I have done the weld up deal. Just make sure you do not warp the shaft causing bind. I have not found it to be worth the time or effort, over the simple 10 minute plug job.

 

The original "intent" of the rule was to allow removal of the PS belt, pump, hoses etc. Then either loop or plug the lines. It was cost effective and easy. Getting into internal rack mods is not what the intention was. maybe the SMAc should look into rewording the rule to specificly say what the intention is. Todd? Ralphie?

 

Spec Miatas have actually 6 different racks.

 

NA power version 1

NA power version 2 (late 97 only) uses 2 large plugs rather than 1 small and 1 large. I have sold over 1000 plug sets and seen this rack 15 times.

NA manual, found only on base model cars (steel wheels, cheap radio, etc)

NB manual, found only on the SSC based race model, very rare on the used market.

NB power

NB turbo power, found only on MazdaSpeed turbo cars. Same ratio as the normal NB power but with less turning angle. Same ratio, but only turns the wheels a total of 30* versus 35* (I made up the numbers for example). This is done by having fewer teeth on the rack shaft. My belief is that this was done to keep the wider wheels from hitting the suspension at full lock. No advantage for our use.

 

I have driven both converted and manual steering cars. For example, if you start with your hands at 9 an 3 oclock and turn to 11 and 5 for a corner with a converted rack. With a manual rack you will have slightly less effort but have to turn to 11:30 and 5:30. IMHO not worth the $700 Mazda gets for the manual rack.

 

Hope that helps

Dave

[speedengineer]

I may be biased, but my opinion, based on over 200 builds, is to buy the 2 plugs that I sell. Spend 10 minutes installing them (plus an hour of cleanup  ) then forget about it.

 

Every rack that I have ever seen go bad has been from someone disassembling it and not getting it reassembled properly. I am not saying it can't be done properly.

 

I have never seen a high mileage rack and pinion fail under race conditions. Unless there was contact with another object.

 

I have done the weld up deal. Just make sure you do not warp the shaft causing bind. I have not found it to be worth the time or effort, over the simple 10 minute plug job.

 

The original "intent" of the rule was to allow removal of the PS belt, pump, hoses etc. Then either loop or plug the lines. It was cost effective and easy. Getting into internal rack mods is not what the intention was. maybe the SMAc should look into rewording the rule to specificly say what the intention is. Todd? Ralphie?

 

Spec Miatas have actually 6 different racks.

 

NA power version 1

NA power version 2 (late 97 only) uses 2 large plugs rather than 1 small and 1 large. I have sold over 1000 plug sets and seen this rack 15 times.

NA manual, found only on base model cars (steel wheels, cheap radio, etc)

NB manual, found only on the SSC based race model, very rare on the used market.

NB power

NB turbo power, found only on MazdaSpeed turbo cars. Same ratio as the normal NB power but with less turning angle. Same ratio, but only turns the wheels a total of 30* versus 35* (I made up the numbers for example). This is done by having fewer teeth on the rack shaft. My belief is that this was done to keep the wider wheels from hitting the suspension at full lock. No advantage for our use.

 

I have driven both converted and manual steering cars. For example, if you start with your hands at 9 an 3 oclock and turn to 11 and 5 for a corner with a converted rack. With a manual rack you will have slightly less effort but have to turn to 11:30 and 5:30. IMHO not worth the $700 Mazda gets for the manual rack.

 

Hope that helps

Dave

Thank you for the insight Dave, that's is very good info. 

[Steve Scheifler]

Jason just leave the dam thing alone and move on to stuff that maters.

Agreed. But I reserve the right to change my mind if you finish ahead of me and contingency tires are at stake.

[speedengineer]

Naw, if it's not legal then I'm not running it.

[Steve Scheifler]

The only way to know is to get an official judgement, anything else is an opinion that wouldn't hold up in tech.

[speedengineer]

The only way to know is to get an official judgement, anything else is an opinion that wouldn't hold up in tech.

I think you missed my point. I'm simply not running the part, and then it's not an issue at all.

[FTodaro]

Jason, if you think about it long enough you can drive yourself Crazy reading ever word of the rules. Since your version of depowing is not giving you any kind of an advantage and you just took a different path to get to the same result, I would not be concerned. I would think that this would never become an issue in the tech shed.

 

There are lots of examples in the rules that tell you, you can do something and do not spell out how.

 

Regarding the Manual rack, the last one I bought about a year ago was 560.00, for an NB. so unless the NA is more expensive, 750 sounds rich.