I wanted to see what people think about the t3 steering rack. I really would like a rack from mtheory and I know its probably better, but It is also 3x more expensive, and he may not make/have any when I go to swap mine.

 

You "get" what you "pay" for!

 

I think anything is better than our stock recirculating ball steering that can be compared to an old truck -lol. My steering wheel play went from 11 to 1 o'clock to now being at 9 to 3 o'clock -lmao. This is most likely from installing the coilovers that have an aggressive 2.5+ drop all around. I would give t3 a try as their parts seem to be well made for the most part when I've seen them in person on people's cars.

 

yeah, there manufacturing looks good. And the only area of concern would be steering geometry right? From my knowledge even a monkey could get that right with simple math. Is there something else people dont like about it?

 

This thread below on the T3 kit is the "only" information I've seen on the the T3 kit for RX7 SA/FB cars on this forum, and it may be worth reviewing before making a decision on what route want to take as far as your steering options are concerned for your project. The information on the T3 kit has been "anecdotal" at best, and not very informative as to final results of the installed kit. You have taken on a huge project with a lot of moving parts and money is "always" and issue resurrecting an RX7 however, a steering kit, in my opinion, is not one of them. I will do without but when it comes to my GSL-SE I've had for thirty-two years cost has never been the determining factor. Only what best fit's the needs for my car to be it's best version of what I want it to be. Almost twenty-eight years of having progressively sloppier steering, the lack of wheel feedback at eighty-plus on the freeway was not what I wanted from my RX7 experience. The MTheory rack & pinion kit changed all that, and I've never regretted spending the money for it. There are other forum members who have installed the Mtheory kit on their cars and have commented on their experiences with the installation, and the results. I hope I don't sound like a "broken record" on this issue but knowing what a difference this kit made, and what a joyful experience driving my RX7 is now. can't be understated. Was it easy paying for it? No! Do I regret buying it? No! Make the best decision you can make in your situation, however, just make sure it's an "informed" decision. I will get off my "soapbox" now.

(https://www.rx7club.com/1st-generati...1168978/page3/)

 

Good post. With age and experience comes wisdom that you can't buy. I don't own anything from MTheory, but believe that he already has a solid enough reputation that even having one of his racks on your car would help its resale if/when it came to that.

I used to hear guys on here wish that they had purchased the re-speed unit when it was available and were kicking themselves for passing on it. I'll bet that in the future, you will see the same thing with the MTheory kit.

 

Good points, I read what scott said about it and it seems not great. Especially the possible exhaust interface for a turbo setup. Ill just go with mtheory.

 

The respeed kit was not great either... lots of U joint bind and the left tie rod was like half the length of the right... can you say bump steer?

The biggest issue with ANY rack and pinion setup is that the inner tie rod pivot needs to be inline with the control arm/strut rod axis when steering straight ahead. The inner almost goes under the engine at full left lock. So for a rack to work the quill will have to be under the engine!

This is why FCs have the rack in front of the engine and extremely short control arms. The engine is just too dang wide at the bottom!

Now, if I were to design a kit, it would replace the steering box with the idler arm from a RHD model and then use a center takeoff rack to move the center link. Steering geometry is retained.
Another idea is like the Australian rack setup for Falcons (the 1st gen is remarkably like a Falcon up front) where they use a center takeoff rack (from a Chevy Cavalier!) and a large bar attaches to the rack's inner tie rod mounting points - this becomes a kind of dummy centerlink that the inner tie rods attach to. I installed one of these in a Torino (very similar to XB Falcon) and it worked exactly as advertised. Also pretty much the only way to get power steering when you have a big block and headers.




The easiest approach is to adjust your driving technique. Cars like this are driven with steering pressure and not steering position. In this respect the stock steering is amazingly GOOD, it is very communicative as to what the contact patches are doing.

I drove my RX-7 (with 46 year old gearbox) for the last two weeks and switched it up today to drive my Mk7 GTI. The GTI has steering ultra precise in position and a very fast ratio. It is also so dead feeling that I don't feel like exploring the car's limits, you cannot feel what the tires are doing... Pressure is more important than position.

 

A lot of the issue is the steering geometry is engineered around donut shaped tires. Tires that have long canoe shaped contact patches. Stock is 165/80R13 with 185/70 as an option. These tires are fairly resistant to change based on road irregularities and such - what is known as self aligning torque. If you go to wider, lower profile tires, the steering geometry built around tires that handle themselves as far as staying straight will now allow the steering to get pulled every which way. This "feels" like loose steering when the real issue is the wrong tires are on the car.

Now, unless you want to buck up for some $300 Vredesteins, we are kinda screwed for performance tires that meet the needs of the steering geometry.

I think a better fix is not in replacing the box with a rack, which will still wander all over the place with modern rubber, but attacking the issue at the source and using new or modified steering arms to shift the strut on the steering arm to change the amount of caster trail. Now the geometry will handle modern rubber a lot better. The stock trail was minimal to keep the steering from being too heavy with those canoe shaped contact patches.

If you could shift the strut backward on the steering arm, trail will increase and it should track straighter with low profile rubber without changing caster.

 

Hmm one could probably 3d print a test piece, and then have it cnc machined. But they would also have to understand the geometry, and i dont. of course I could always learn. Then just to fix the leaking seals.

 

It is way too simple to bother with CNC, a manual mill can handle it or even just a drill press and files... CNC is great if you want to run a batch of fifty.

Depending on how far it needs to be moved, you could even just engineer it into a roll center corrector plate. Or plug the holes in the steering arms and drill new ones.

 

Wouldnt that interfere with the top of the balljoint, i like the sound of the roll adjuster situation. But that sounds above my machining skills currently.

 

This has been a very informative thread. I don't plan to update the steering anytime soon but definitely in the future. For now, what do you guys recommend for tightening the steering a bit? Should I raise the springs in the front (coilovers) and try readjusting the recirculating ball socket steering?

 

Make sure the wheel bearings are properly adjusted, make sure the inner control arm bushings are good (no polyurethane junk here, rubber only!) and make sure you have a small amount of toe-in and positive camber.

The biggest destroyer of steering boxes is people overtightening them trying to solve issues caused by the above faults.

 

Do you think raising the vehicle will help or should i align the car first and adjust camber/toe? The BC racing coilovers have camber plates on them.

 

I was one of them. Almost bought a respeed kit locally for way too much. Luckily someone got it before me. Was also trying to get someone that had a respeed kit to 3d scan or take measurements so I could reengineer the kit. But like u said that kit had many flaws. What I like the most about mtheory kit is it keeps the stock steering geometry. Super simple. Car drives like a go kart. T3 Ackerman is all goofy. Steering arm should always be even with lower arm. Like mtheory kit.

 

The mtheory rack does not anywhere near keep the stock steering geometry.

 

I think its a matter of least compromises.
The main problems I have are leaky seals, and the steering wheel has about 3/4 turn of free play. I dont know if its the sector shaft or the big nut on the steering collum.

 

Ok. Its rear steering like stock. Probably better than stock steering geometry. Drives like it does.

 

As long as you stiffen up the suspension so it doesn't move. It looks like the tie rods will be 2/3rd to 1/2 as long as they should be, which will cause some righteous toe out in compression and in bump.

Key to good handling is allowing the suspension to move, which is why the 3 link rear suspension is a game changer. Without it, you have to stiffen up the front end a lot to match the rear suspension's inability to articulate. "Any suspension will work if you don't let it." The benefit is in being able to make the suspension softer than you could otherwise, which makes the car handle imperfect surfaces a lot better, which is important for pretty much anything that isn't a Formula 1 grade ultra-groomed track.

Now, what WOULD make that work, would be if they could kick the rack a couple inches to the rear, and attach the inner tie rods to a dummy rod that bolted up to both sides of the rack. I saw someone do this once when putting an S2000 rack into some really narrow English car.

 

I know what your talking about and have seen it on r&p kits for old 50's American chevys. But Im pretty sure your Ackerman wouldn't be right. I will admit I'm a big fan of mtheory kit. But I never bought one. I made my own. It's a simple ingenious design. That works extremely well. ( He made a right hand version too ya know) Took two attempts to get it right. U need the rack as far forward as u can get it. Literally 1/4 inch or more towards the back. Changes everything in a big way. Almost undrivable. U don't need to change a thing with his design. He found the recipe and it works. Really well. Completely changes the car in a good way. Drives like a go kart. With no short comings like other r&p kits in the past.

 

You're right, it is better geometry. Thank you!
My steering conversion pairs perfectly with the FB's front end. This isn't a matter of opinion. It is an established fact, validated through extensive alignment data and direct comparison against OEM parameters for roll center and bump-steer characteristics. This includes real-world track and street testing by happy customers all over the US and around the world, not to mention how many I had running The Tail of the Dragon at DGRR 2026.
The OEM geometry was engineered for straight-line stability and low production cost rather than high-performance cornering capability, and it features mild bump-steer from toe-in on compression with roughly 1/8 to 1/4 inch of toe-in per inch of upward travel.
Bottom line: My steering conversion just flat-out feels great in the first-gen RX-7 without reinventing the wheel, and in a way that doesn't hack up our cars.

 

I wanted to clear up a pretty common misconception about MacPherson strut rack & pinion conversions.
A lot of the old "rules of thumb" say the rack's inner tie-rod pivots have to line up exactly (same lateral distance and height) with the lower control arm inner pivots to kill bump steer.
That's not actually true.
The tie-rod centerline just needs to intersect the suspension's instant center (IC) in side view. When it does, the tie rod and lower control arm swing on matching arcs through travel, so the knuckle stays at consistent toe.
In a MacPherson strut, the IC is defined by:
1) the line running from the lower ball joint up through the strut top mount
2) the line running through the lower control arm's inner pivot and outer ball joint
As long as your tie rod is aimed to hit that IC, you're good to go.
All of this isn't magic, it's engineering. Nothing lives in a perfect environment, so there will always be some form of compromise.

 

sounds legit to me from my YouTube knowledge. Now I just need money. Would your kit require an rca on a lowered car.

 

1/8 to 1/4" of toe change per INCH of travel?

Maybe fine if you stiffen the suspension up so far that it doesn't move.

Experience and video show that the suspension moves way more than that when driving on the street.