Thucydides

I don't know anything about Spec racing, but what you say does make sense from a rules point of view, though I would think Spec racers would probably prefer a true manual rack for durability and rules sake; or if they did de-power, perhaps many are running welded pinions despite the rules. Perhaps they swap racks when theirs becomes sloppy or just stops working; I just don't know. But not welding the pinion is a major compromise in precision in exchange for not that much effort. It only takes an hour or two to remove and replace a pinion shaft.

sjmarcy

On welding…

The pinion shaft's skinny core twists with steering input. However the amount is limited by the spline slop midshaft. If the skinny rod twists all the way, the spline slop is used up and from that point onward during that steering input in the same direction the shaft acts like it is one piece until the torsion comes back down. This acts as a safety factor, so that the skinny core rod does not eventually fatigue out and break. When you weld, the spline slop becomes inactive since the load passes through the outer welded area too. If your weld ever broke (unlikely), the remaining center rod will keep you from dying young. You can see the end of the skinny torsion rod at the rack's splined input which is where the steering column connects. It sticks out a bit past the spline. Some on the net freak about welding. This is actually a forgiving weld effort. You don't need to use special rod/wire. No you won't die like Senna. In that case they had butt welded the actual main shaft - ugh.

Some of the internet how-to sites I have read leave many seals in place besides the center of the rack piston seal. The rack comes pressure sealed in two main areas. The part of the pinion shaft where the spool valve lives. And either side of the center piston on the rack. The rack and pinion gear mesh zone is greased on both manual and power racks. On racks I have seen there are three pressure seals in the rack tube and at least two in the pinion shaft housing. Each seal adds some drag and uneven breakaway stiction,
so if you won't need them to hold in high pressure (1000+ psi) hydraulic fluid then remove them.

If you are doing a rack depower, track down ALL of the internal pressure seals so that you can cut friction / steering drag. This slightly lowers effort and mostly helps improve feel.

Faeflora

iTrader: (2)

What the ever living **** are you saying? I accept responsibility for failure to comprehend, but this makes me question god's purported benevolence.

It sounds like this is the most complicated thing ever.

I just want my **** to feel good and not wear out and be horrible.

MartinezA92

iTrader: (4)

God ******* dammit.
I should probably weld my pinion shaft too. Does anyone have more detailed pics/instructions? I feel like it is being made to sound more difficult than it really is...

I looped the lines when I pulled my engine and have not touched it since. There is a considerable amount of slop in the steering wheel.

timk

I did this mod to my NB and it is baller. I didn't weld the pinion just removed the seals. Makes the car feel like a little go kart!

Laur3ns

What about the whole overheat-during-welding-issue-and-killing-the-rack-shortly-after story?

sjmarcy

It's an easy project really. Really. It's simply unfamiliar to most. Everything seems weird the first time you open up a manual transmission too. But they are also relatively simple.

hustler

iTrader: (6)

Good grease will stop friction.

lol @ external damper

Slowing it down with the looped lines makes it too hard to turn, been there, done that.

Caster won't make the steering heavier, it will make it harder to turn and easier to spring back.

Faeflora

iTrader: (2)

The most complicated car mod to grace miataturbo.net???

sjmarcy

Rubbish.

sjmarcy

Boost is for motors, not steering.

hustler

iTrader: (6)

It's pretty easy unless you're a trophy-bottom.

pdexta

iTrader: (17)

At least I'm not the only one that feels this way.

This seems like one of those things where I finally build up the confidence to pull it all apart, screw everything up, have to buy another rack, wait for it to get delivered, and after a month of not being able to drive my car and spending $200. I'll be able to put it back to the same looped lines I had before I started.

sjmarcy

Good judgement comes from experience. Experience comes from bad judgement.

I'd suggest that if you are very new to mods like this…hire it out. Or DIY using an extra rack so that you have no down time and it's less stressful. You need tools like snap ring pliers, various sized sockets to punch out seals, five minutes of access to a welder, and the interest. The second time you do one will take a fraction of the time of the first.

Thucydides

So the grease defeats the friction you added by over tightening the rack pre-load.

Yeah; what was I thinking. Race cars never have steering dampers; those are for monster trucks. Oh wait:

http://forum.britishv8.org/read.php?7,17819,23898

I agree, but then I don't crank down my pre-load either because I don't have problems with too light a steering on my de-powered racks.

Well, perhaps I don't know what you mean by making the steering heavier, and why you think you need it. Perhaps the problem you're trying to fix with the steering originates somewhere else in the suspension, and you're using a band-aid instead of solving it.

sjmarcy

Spend some time driving a Lotus….now THERE is excellent steering and feel. I've had three over time, from Europas to the Elise. BTW, those cars are all so light that you can kneel down by a front wheel and "turn" it, watching the steering wheel spin inside the car. Try that on nearly any other car if your arms are not the size of legs.

On modded Miatas, it would be nice to see drop-spindles used to keep the articulation happy at low ride heights. Much lowered Miatas suffer from various issues which harm the steering characteristics.

You can feel the sport-driving steering improve as you go from power to looped-line manual to tweaked-manual steering.

hustler

iTrader: (6)

Define "over-loaded". Actually, don't. If you're so dense that you think I added 100lb/ft instead of something reasonable then you're beyond hope. This also reduced the slop.

Fab up a steering damper for me, for free.

I added a little pre-load because I like the way Porsches steer more than BMW feel. Maybe you can ask Porsche about their suspension problems.

hustler

iTrader: (6)

Maybe I like the heavier steering because I'm so pumped and masculine. I drove a Porsche once and fell in love with the heavy steering. You could still feel the pavement texture through the wheel, but I felt like the wheel was nice and heavy. In my daily driver Miata, it's too whippy and I saw at the wheel.

sjmarcy

I hear ya…well I don't have 22 inch pythons attached to my shoulders like Hulk Hogan haha. I love German car control-efforts. The solid brakes, heck the whole car is solid.

Part of the thing about Miatas is that the wheelbase is so short. If you think about it…that can create some steering issues at high speeds that will certainly catch your attention. The Lotus car also has a short wheelbase but they manage it fairly well. For instance they use deliberate and coordinated front/rear bump steer to good effect. And a goal chassis torsional rigidity has been achieved. A nice thing about the small Loti is their initial turn-in…the next time you drive one pay close attention to it. They have their issues, but there is absolutely zero whippy steering feel at speed.

Much of your concerns with Miata steering could be ameliorated via new front uprights and similar design level changes. When you design a suspension system, the uprights are one of the core assumptions. And ours were designed to be cheap while handling stock power levels and speeds.

sjmarcy

Here is a rack I converted to manual. I like to clear coat the aluminum casting after steel brushing it once it has been degreased. This fills in the casting pores so that it stays clean and shiny. On this one I cut off the nipples that live on the black tubular section. It just looks sleeker. Fluid line ports on the alloy casting were JB Welded flush, as you can barely see in the picture.

https://www.miataturbo.net/attachmen...1&d=1311268120