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Discussion Starter · #101 ·
Sounds like you are on your way! Not surprised that some fine tuning is needed to dial it in. Can’t wait to hear the results. You have the ARC option correct? I’d be inclined to take a pound out of the rear tires before making adjustments to the units. Then do the same with the front (set the rears back up), then take out of both ends. That will give you a starting point for the TP adjustments as you play with the compression/rebound. I find on 17/18 re71r on base suspension, I like 24lbs/26lbs cold.

car looks awesome, I am using the same OEM style wheel painted all satin black.
Hi @peterA116 , yes , I have ARC. It works very well. The section of road I tested on is very uneven with lots of small dips and humps (nothing sharp-edged) and it was a hoot. She now corners flat (with just a very slight lean). Much better than on the standard suspension. There’s no bottoming out or grinding of @cipsony ’s diffuser fins as had occurred at those speeds on the standard suspension. I tried a few braking tests, getting more aggressive each time, and there is much less dive and more stability. Really happy about that. A huge improvement. The stability thing could also be partly from the Cup2s I’ve recently put on. She felt much more like @alfa1105 s’ 4C. Much more planted at speed over bumps than before. No steering oscillation/vibration at all when going over bumps. Lots of confidence. Not perfect. I’m going to increase the damping rate at the rear to see if that cures the annoying low speed bounciness. There was a dip and hump section of the road where I felt the nose of the car lift and bounce once. The front probably needs to be turned back a few clicks too. It’s certainly got me thinking.

Thanks for the tip about pressures. I reduced my pressure by 2psi after I checked them. They were overinflated due to higher ambient temps than the last time I used my car. I might drop them by one more psi. Even though they are standard sizes the Cup 2s are much wider than the P-Zeros. Stiffer sidewalls too. Sharp edged road joints appear harsher too. Maybe it’s the Cup 2s.

Summary so far. After my first drive, with damping set right in the middle of the range on both front and rear dampers, the Intraxes perform much better at high speed but more poorly at low speed than the standard suspension. A bit of time sorting is definitely required.

As for the much derided standard wheels, to my eye they look much better in a colour other than silver. Silver, I think, doesn’t do the design justice. Almost everything on the road has silver wheels and I’m well and truly over it. My new wheel colour is growing on me. Happier by the day. They look pretty good but best of all they are light with a standard width tyre combination.
 

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Discussion Starter · #103 ·
Well done Jim, I'm sure with a few
twicks you will be able to have them where you want.Alot to take in on first drive, the second will be better.
Thanks, Dario. Taking Cath to the Elvis movie this morning. I’ll get the 4C up on the QJ this arvo. Won’t have time for a drive I don’t think. Mitch has a few days off work before his Uni grad ceremony on Tuesday so we’re heading up to Port Macquarie in the G for a few days. I need to get some salt air to try to beat the remnants of Covid that’s hanging on like a leech. The next test run will be towards the end of next week.
 

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Too bad the front wheel needs to be removed to make adjustments. You need a pit crew, a road day and a track day. And a chat with Intrax. Gonna have to keep a log book, maybe you already do that. Stiffer in the back to better control the rebound? Good luck. Glad the ARC seems to work so far.
 

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Discussion Starter · #105 ·
Too bad the front wheel needs to be removed to make adjustments. You need a pit crew, a road day and a track day. And a chat with Intrax. Gonna have to keep a log book, maybe you already do that. Stiffer in the back to better control the rebound? Good luck. Glad the ARC seems to work so far.
If you had a pit in your garage it would help heaps. The problem with adjusting the fronts is there’s no clearance to reach around between the tyre and the wheel arch and liner. Unless someone has any other idea you need to at least lift the front to gain access and see what you are doing. Maybe when using the QJ there will be enough sag in the wheels when the car is lifted to be able to reach around but I’d rather see than feel. Doing some adjusting this afternoon so we shall see. Hopefully it’ll just require lifting rather than lifting +wheel removal.
No log book but using ‘Notes’ on my iPad to record settings and characteristics. Same thing, I suppose.

Edit: Another aspect about the Intraxes is they are supposed to have a thermostatic valve so as damping rate is maintained as internal temps rise. We’ll see how effective this feature is, in time.
 

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Discussion Starter · #106 ·
That Elvis movie was long. 3 hours in the cinema, an hour for lunch, the drive home (30min), a bit of a snooze, some time perusing the Forum and communicating with an old school mate on fb about the movie of all things, took the dog for a walk and then it was time for dinner. What happened to the day? Going to my holiday apartment tomorrow for a few days so won’t be doing anything with the 4C until Wednesday. Apologies for the broken promises.
 

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Discussion Starter · #107 ·
I lifted Rosie today. Once the wheels are off the ground there is enough wheel droop to reach in and make adjustments to the front but it’s an awkward reach. Much better to remove the wheel. That aspect is a pita. The rears are easy peasy with a recessed adjuster knob at the base of the shock.
I haven’t yet been for another drive...That’ll be on Friday.
Spring Specs ...Front: length 150mm, rate 50N/mm Rear: length 220mm, rate 45N/mm, Inside diameter 70mm.
Automotive tire Gear Material property Camera accessory Gas

Tire Automotive tire Automotive lighting Hood Alloy wheel

Gas Cable Audio equipment Automotive lighting Metal
 

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Discussion Starter · #108 ·
It’s a day of drizzle so no testing. Monday it will have to be. I’ve reset the fronts from -25 clicks to -23 and the rears from -20 clicks to -17. Testing run on Monday.

These are what the coilovers look like on the car.

Rears: The adjuster is at the base of the shock body. Notice the colour coordination with the braided brake lines.😉😂
Hood Automotive tire Camera lens Automotive lighting Reflex camera


Fronts with adjuster indicated.
Automotive tire Automotive lighting Hood Automotive design Motor vehicle
 

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Discussion Starter · #109 ·
I went for a bottom third Putty run with @Alf Alpha this morning. Thanks for the observations, Alf. Your input helped heaps. The bouncing is still there at slow speeds, though much muted. I’m glad Alf was sitting behind and he noticed the bounce at slow speed too so pleased to know it’s not my imagination. The fronts are now planted. Going over that dip and rise the nose lifted then settled with no second nod. The rear at speed feels really nice and planted. Firm, controlled and comfortable with minimal roll. It’s just the slow speed ride that is a touch out of place. Still, the high(ish) speed stuff saw no bottoming, no scraping of fins, no shake or flick of the steering. This was the piece of road for which they were purchased and she’s running over the ground there very, very nicely. Really secure and planted. Maybe it’s the compromise I’ll have to make but it’s still early days. Maybe drop another psi in the tyre pressures then test…then increase rear damping by another click or two.

Overall, the huge improvement in high(ish) speed handling over the standard suspension is at the expense of slow speed characteristics … but things are improving with adjustment. Not there yet.

Thanks also to @JTod for pointing me in the right direction. 👍🙏
 

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Discussion Starter · #110 ·
I’ve spent 5 days from last Friday up the coast (A hard life, but someone’s got to do it) and only just now have gone on another short test drive. I think that bounce is now much better controlled after taking off another click at the rear. Bounce is just about imperceptible on suburban back-streets and non-existent at higher speeds. As a ride-handling compromise for the roads I use in the dry I think I’ve found the sweet spot….Maybe slightly too firm at the front but I’ll keep it at F-23clicks and R-16clicks for a while. Firm yet fairly comfortable. Roll is nicely controlled. I also returned to standard pressures. F 26psi and R 29psi. Temp was 18deg C. [Note: F 0clicks is full hard and -50clicks is full soft; R 0clicks is full hard and -40clicks is full soft]

My big criticism is the difficulty in adjusting the fronts when out on the road. You need to find a road edge with a few inches of drop-off to extend the suspension on one side so as to be able to reach the front adjuster. Then you have to manoeuvre the car to use the drop-off on the other side. Not impossible to do but a nuisance. It kind of makes a farce of trying to make quick readjustments on the run for wet weather, something that can occur when on tour. Rears are easy to adjust when out of the garage.

Overall there’s been a massive improvement in stability and control on rough roads, through bends (much less roll) and under brakes (much less dive). It’s definitely not as comfortable and compliant as the standard suspension though it’s still pretty good. It’s a compromise I’m willing to make (after spending so much there’s no chance I’m turning back) but as with all things, you can’t have your cake and eat it too. Comfort has to be compromised to improve handling precision. So it is with these coil overs but they are pretty bloody good at the compromise.

I haven’t yet tried it on recommended comfort/wet settings nor track settings. Those’ll come eventually.
 

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Any thought on the effectiveness of the ARC feature. I understand this will be without a comparator but it is supposed to be more compliant over smalller road imperfections and bumps while reacting to stronger cornering forces, bigger bumps and compressions. The other question is the choice of single adjustment for rebound/ compression versus separate adjustment?
 

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Discussion Starter · #112 · (Edited)
Any thought on the effectiveness of the ARC feature. I understand this will be without a comparator but it is supposed to be more compliant over smalller road imperfections and bumps while reacting to stronger cornering forces, bigger bumps and compressions. The other question is the choice of single adjustment for rebound/ compression versus separate adjustment?
ARC is very effective. I’m without a rear anti roll bar but you’d never know it with these. Maybe it’s more compliant than other coil overs but certainly not as compliant as the standard suspension. It’s not harsh most of the time but it’s firmer. Road joints are dealt with more poorly than the standard dampers and springs but there’s no bottoming out on large dips and road bumps and no sideways skipping when you hit mid-corner bumps at the speeds I travel on these roads. Anyone who has travelled on the Putty Road for the 30km past Colo heights knows how bumpy it is.

Just to emphasise, I’ve been trying to achieve a good fast, dry road set-up and haven’t tried adjusting for comfort or for the track. The bounce I was getting at the rear at slow speed, when the rear dampers were set at -20clicks, makes me think it will be even more pronounced the softer it’s set. If that is the case it would be annoying at slow, suburban road speeds. Roads around here aren’t all smooth and flat.

The rebound and compression rates are supposed to be optimally set. For how I’ve used the car so far I’ve no complaints when driving enthusiastically. I’m feeling much more controlled, less on the edge. The tyres are staying in contact with the road over sharp dips and bumps. There’s no skipping or bouncing and I’ve not been launched skywards so I’d say Intrax is true to it’s word about matching rebound and compression. They seem well-matched.

These are around $6,000USD but after import duty and taxes in OZ they are $11,500AUD. That’s a big spend to get that extra 5% of top-end performance. If you don’t drive your 4C with much enthusiasm these would be a total waste of time. The standard suspension is very compliant and comfortable and fun on Pirellis. For 95% of my driving it was completely adequate. It’s just when pushing a little harder that the body roll and dive became an issue and then there was the track. The new suspension is firmer and less comfortable but not by that much and that’s on a good fast-road setting. I’m satisfied with what I’ve gained in spite of sacrificing that lovely standard compliance. It now feels taut, not loose and there’s more feel through the steering wheel. Overall it’s now better for my use of my 4C. I’ve achieved the fast road goals aimed for but have also lost a little something at the slower end. And that front adjustment away from home is a pita.
 

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That’s great feedback, good to hear about the ARC.. The import duties are ridiculous.

I have already given up some of the suspension compliance using re71 as a road tire, even at the 215/245 size. I suppose the coilovers could be set a little softer to account for the differences in sidewall stiffness. Annoying that the front adjustment is difficult on the fly.

Thanks!
 

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Discussion Starter · #115 ·
Hi Jim, have you put anyone in the car since playing with your settings. I mean did it behave any different with extra weight in it?
Hi Dario, No Cath’s not been out with me in the 4C since the Intraxes were fitted. Once I’m certain of the fast road settings solo I’ll take her for a run in it. That’ll probably be in the next couple of weeks. I’ll be solo on the Sofala drive but was tossing up whether to change back to my Pirelli wheels. The day looks dry so probably not. Haven’t been home much over the past couple of weeks. That’s why no regular updates. Still enjoying the beach up the coast. Walking there now, actually.
 

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Discussion Starter · #116 ·
I drove well over 400km yesterday. I think a lot of the harshness over road joints etc has to do with the Cup2 tyres. In the morning, with cold temps, there was a definite roughness to the ride but by lunch time, with ambient temps a little warmer and some heat in the tyres, the ride became noticeably more compliant. I’ll swap back to the Pirellis before Concorso (within the next two weeks) and see how they feel with the new suspension.

These do work well. The harder you drive the better they work…..which can have it’s own set of problems on the road.🙄 But that front adjustment while out and about…..😕
 
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