[RKBerta]

We are discussing potential improvements...

View attachment 123363

4C has fixed ratio of 15.7:1 and has 2.7 turns of wheel for lock-lock. For each turn, rack moves 44mm.

Compared to 991 GT3RS it seems on a 4C you need much more of counter steer for corrections. At the same amount of oversteer, the GT3 required minor steering wheel input compared to 4C, yet it felt more precise going straight. One thing that I remembered the most about this car driving it on a track last time. GT3 RS has variable ratio steering rack, 4C has fixed ratio.

BTW, Giulia QV has a steering rack ratio of 11.8:1, one of the quickest.

Is you sped it up that would mean more muscle to turn at slow speeds and it already requires a bit of muscle to turn it at very slow speeds like in parking. That may explain why ALFA settled on that ratio.

 

[GMS]

I agree, but unless you're turning the wheels standing still, it's pretty easy to rotate the steering wheel, even with wider tires. On my other cars, even with assisted steering I never standstill and rotate the wheel as this only kills the tires, instead I slowly move the car and rotate the wheel. Most of those coming from non assisted steering do that, while those having assisted steering since ever, not really. On 4C, as long as you're moving at least slowly, it's really easy to rotate the steering wheel, isn't it?

A bit more insight into to the 4C's steering...

One of the reasons the 4C has lack of self centering is low kingpin inclination angle in combination with low positive caster, which causes the car not to jack up the wheel on turning which makes the steering wheel feel light even without assist, but on the other hands the straight line stability is poor and even lacks a bit of feedback (it's hard to tell how loaded the front wheels are, as the jacking supposed to do but on a 4C there is, almost none. You can tell that by rotating the steering wheel while standing still and you can see that the car's hood/nose doesn't raise or lower). Make a full lock and take away slowly, you'll see that the steering wheel doesn't even self center. Alfa added relatively slow steering ratio to further ease the rotation of the steering wheel, but on the other at least for me it felt a bit unnatural. It requires a relatively lots of steering angle input for the oversteer corrections. You get used to it, but variable ratio would be a great improvement. Steady and calm on center, yet responsive on corrections. I'm not sure if we can make it as it's quite complicated though...

 

[GMS]

A bit of update.

We have managed to get a spare steering rack by a fellow 4C owner. Thank you Jimmy. The steering rack was replaced because it had signs of free play, but it turned out that the free play came from the inner tie rod and not the rack itself. Unfortunately inner tie rods are not available separately, so entire steering rack assembly must be replaced. To sort that out, we'll have an inner and outer tire rod kit made, which will allow for replacing only of the worn out parts, not entire steering rack anymore. That should save a huge amount of money to 4C owners when they come across this issue. Second and to me even more important feature is, that we'll eliminate the rubber dampening part in the inner tie rod, which serve as a vibration damper, but on the other hand also filter out lots of steering feedback to the hands of a driver and the precision of the drivers steering input. I can assure you that this will make a great improvement to the front end steering. Once we finish this, we'll evaluate the options of modifying OEM steering rack to variable steering ratio rack.

 

[GMS]

We've been discussing potential rack fabrication with some of the companies, unfortunately we cannot justify the costs of realizing this project. Custom ratio, variable rack would cost us north of 5k€ for prototype alone, so it's not really viable. Quicker ratio gear is doable, but it's not really what I'm looking for, so I'm not into this option. Car would feel to imprecise at high speeds.

However, we are testing the inner tie rods (without integrated rubber inserts), outer tie rods and solid bushings instead of rubber (where steering rack is mounted to the chassis) and I can say that there is a noticeable change in the steering feel. More direct and responsive, more communicative if you like, easier to read what the front end is telling you and I really like it. We expect to have this 3 parts available soon. This will allow you to replace inner tie rods, without the need of replacing entire steering rack once they wear out (not available as OEM spares) and more sporty steering feel.

 

[FLORO]

I’m going to look into this thing. If it checks out, I’ll add that to the jobs currently being done.
.

Steering rack quickener 1 : 1,5 ratio

Alloy steeringrack quickener. Ratio: 1 : 1,5Length: 200mmWidth: 63mm

www.speedingparts.co.uk

Or this US made one. It’s only just over £100 too.

or this one

 

[GMS]

That would do if you're looking just to quicken up the steering ratio overall.

...I was hoping to get variable steering rack done, that would quicken it off center (on countersteering) and make it precise and slow enough on the center. I'm not sure I'd want just faster overall steering ratio as I personally find the OEM setup already a bit wandering around on the center, but give it a try, perhaps I'm wrong.

 

[FLORO]

I agree it’s no good. The 1.5:1 “quickener” will change it more than I want. 2.7 turns becomes 1.8!
I see you can buy refurbished Honda Accord variable ratio racks for cheap, with warranty. Maybe one of those could be made to fit. Maybe with a quickener to speed it up overall.

All in all, it’s not a priority. I’m not that bothered by the steering as is. As with all things, you can find fault but nothing broken.

Edit. 1.8 turns lock to lock may be ok. I just saw the 147 GTA came with 1.75 turns lock to lock. I’m trying this quickener

 

[u.k.sharif]

I agree it’s no good. The 1.5:1 “quickener” will change it more than I want. 2.7 turns becomes 1.8!
I see you can buy refurbished Honda Accord variable ratio racks for cheap, with warranty. Maybe one of those could be made to fit. Maybe with a quickener to speed it up overall.

All in all, it’s not a priority. I’m not that bothered by the steering as is. As with all things, you can find fault but nothing broken.

Edit. 1.8 turns lock to lock may be ok. I just saw the 147 GTA came with 1.75 turns lock to lock. I’m trying this quickener

Watching with bated breath

 

[Curvesurfer]

Subscribing.

I have a power steering unit on order and am curious about a faster rack too. On the fun roads I enjoy the 4C is a wrestling match: high effort and crossed-up arms on the really tight turns. Seems I’m not the only one who shifts to 8 or 4 to get enough leverage. Yes I have suspension upgrades and alignment. That made the car far more predictable. But the heavy manual steering and the slow rack it requires just aren’t well suited to fast street driving on truly twisty roads.

Compared to a Lotus the 4C steering feels like a dead power rack. Numb, and load through the steering wheel masks perception of loads on the chassis and tires. I’m sorry, it’s not a feature. I love the 4C but Alfa spent the whole budget on the glorious tub and had nothing left to sort the steering / suspension.

For perspective I drive the same roads in a Porsche Spyder, M2CS, Miata…and manual rack ‘71 911 and Ferrari 328. Only the Ferrari is as challenging. There’s a reason why power steering / faster racks became the norm.

 

[Curvesurfer]

Rudi, do you know if 3/4” 36 spline spec of these 1.5 quickeners is the right one for the 4C?

That would do if you're looking just to quicken up the steering ratio overall.

...I was hoping to get variable steering rack done, that would quicken it off center (on countersteering) and make it precise and slow enough on the center. I'm not sure I'd want just faster overall steering ratio as I personally find the OEM setup already a bit wandering around on the center, but give it a try, perhaps I'm wrong.

 

[GMS]

OEM Steering rack has spline with 22 teeth and diameter of 17,60mm.

 

[Curvesurfer]

Thanks! All the common quickeners seem to be 3/4” and 36 spline…

 

[John4C]

Subscribing.

I have a power steering unit on order and am curious about a faster rack too. On the fun roads I enjoy the 4C is a wrestling match: high effort and crossed-up arms on the really tight turns. Seems I’m not the only one who shifts to 8 or 4 to get enough leverage. Yes I have suspension upgrades and alignment. That made the car far more predictable. But the heavy manual steering and the slow rack it requires just aren’t well suited to fast street driving on truly twisty roads.

Compared to a Lotus the 4C steering feels like a dead power rack. Numb, and load through the steering wheel masks perception of loads on the chassis and tires. I’m sorry, it’s not a feature. I love the 4C but Alfa spent the whole budget on the glorious tub and had nothing left to sort the steering / suspension.

For perspective I drive the same roads in a Porsche Spyder, M2CS, Miata…and manual rack ‘71 911 and Ferrari 328. Only the Ferrari is as challenging. There’s a reason why power steering / faster racks became the norm.

Interesting project. I’m curious to hear how this turns out.

 

[FLORO]

I got weld on couplers. I’m going to buy another column shaft to butcher so I can keep mine in the growing collection of replaced parts.

 

[FLORO]

So I bought a donor steering column for this project. It’s a used Giulietta unit but it looks the same and cost a tenth of a used 4C unit.
I only want the splined ends/couplings to weld to my quickener couplings. Then I can attach the quickener or remove it and replace the unmolested factory parts.
Here’s a 4C column - available for £220

Here’s the Giulia column - cost me £22.56 including P&P

 

[FLORO]

I built the “quick column” with the Giulia unit and 1.25:1 quickener. Did it last week but didn’t get around to posting with other stuff going on l. It’s not a simple thing because it has to cope with steering wheel tilt adjustment as well as the standard misalignment between the rack and wheel so you have to make a support for the quickener that is solid and rigid, but tilts.
I’m away till the weekend but will be installing it when I get back. Best part is, if I don’t like it for any reason it’s only a few screws and bolts to swap it back.

 

[FLORO]

So I’m fitting this 2 turn quick column I built. First removing the factory one is a serious pain as you have to work upside down in the footwell. I got as far as removing the shrouds and steering wheel and electric connectors but then the blood in my head got too much and I had to leave it for tomorrow but there’s only a few 13mm nuts and bolts and the column will be off.
I hope swapping things over doesn’t present any unexpected issues. Unlikely, I know.
here’s the Giulia column with Howe 1.25:1 quickener mounted. Still tilts and everything. Welds aren’t pretty but the steel is heavy gauge and everything was welded both sides, inside out and top to bottom.

 

[FLORO]

As I hoped, only the handle on the adjustment lock is different. Since the cover won’t fit over my Quickener, it’s no matter. I just hope my knees don’t hit the bracket.

 

[FLORO]

Just went for a road test. Its actually less than 2 turns lock to lock. About 1.8 I’d guess. Honestly, I was expecting it to scare me but it’s great. Still feels normal really, just turns easier. It’s a very satisfying feeling, more direct and connected.
Only thing to bug me is that after a couple of days with the battery negative disconnected, after a short distance I got a message saying hill hold unavailable and the traction control light came on and DSC said unavailable. I’m hoping a battery charge up will cure it.