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2015 Alfa Romeo 4C Launch Edition #444
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Discussion Starter #1
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(link above to my “build” thread/introduction)

BACKGROUND
As of tomorrow I will have owned my 2015 4C LE for exactly 4 weeks. In that time I’ve manage to put just over 1,000 miles on the car already! Shortly after purchasing the car I decided to get new tires (215/245 Conti ExtremeContact Sport) and a new alignment. At that point the car felt 75% better; more confident under load, and more enjoyable to drive hard in the 30-70 MPH range. However the car still felt light/vague on-center at expressway speeds, and the lack of return-to-center made the car overall not as fun to take anywhere that required freeway driving. But pushing the car hard was a blast on some of my favorite back roads. Additionally, driving the car *(always in Dynamic mode) one could feel the shift slop In the lower motor mount.

MOTOR MOUNT BUSHING
Wanting to firm up the shifts, I purchased the PowerFlex Race (Black) bushing insert, which also includes the nylon sleeve for the bolt. I honestly did not expect much, as my past experiences with motor mount bushings is that you usually have a lot of NVH, for moderate gains. However, I could not be happier! Shifting is super crisp, and the throttle feels far more connected to the chassis— not just shifts, but even tip-in on the accelerator. And with basically no notable NVH worsening, this was perhaps the BEST mod I’ve done to date. Highly recommend!

SUSPENSION BLOCKS
Oddly named, most forum members know these blocks replace the factory mounting blocks with ones that dial in more caster. Based on reading here, I anticipated the car would track better on the freeway, and it DOES! It pleases me to say that the other 25% that I wanted is now resolved, and the car’s desire to track straight allowed me to drive with much greater confidence at 70+ MPH (did one “pull” on the expressway to a respectable albeit not legal speed and the car felt really solid). However, the end result is not 100% because...

There is a notable increased effort to steer the car. This is not noted at < 25 MPH where you already had to put in a fair bit of effort anyhow, and you really wont feel it on the road at > 70 MPH because the steering input angles are never that great (maybe on-track you’d feel it, but 99% of my car seat time will be road, not race). But at speeds between 25 and 70 MPH you feel it; and after going back, revisiting some of my favorite roads, I noted the extra arm effort, and steering input, to make the car rotate. Turn-in is delayed, and understeer is amplified. The car has moved slightly further in that direction, for the sake of the caster.

For those curious, my final #s:
Front Caster +4.42 degrees
Front Camber -0.99 degrees (shims maxed out due to threads)
Front Toe +0.09 degrees (toe-in)
Rear Camber -1.74 degrees
Rear Toe +0.30 degrees (toe-in)
(all this obtained with the “fast road” AlfaWerks blocks)

CONCLUSION
At this point I plan to drive the car more before I tinker. I’d like to make the car turn in quicker, and I have to wonder if going ZERO front toe (instead of toe in) would help. Or, dial in a bit LESS toe-in in the rear. Anyone who has any experience here, I’d be happy to listen. I’d also expect some sway bar changes could dial this in. I’d say the car is 95-98% perfect ... and I’m inclined to not make any major changes.

Would I do the blocks again? Probably, because I do a decent amount of expressway driving. I’d expect that 25% of my miles on this car will end up being at 70MPH or greater, so I want the car to feel good. If you do 10% or less of your total driving on the freeway, then I think the first steps I did (a good Alignment) may be adequate. Obviously there is also some subjectivity here— what you like the FEEL of matters For a road car. If we’re talking about what is fastest around the track, there is a mix of objectivity there, as well as subjective to what provides that specific driver the confident they need to drive the car at the limit. But it is more weighted towards objectivity. (One could argue that my car’s current setup is objectively “safer“ because of the under steer, I suppose— but lets not go down that rabbit hole haha)

Thanks for reading!

116268



PS: First photo in this post is at the ASM HQ (see link above). Second photo is my 4C with my Audi R8 .. except that my friend now owns the Audi R8 ... how I miss that car. (We cruised around this weekend, very fun!)
 

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so you have less than 1 degree of negative camber on the fronts? it's a little ridiculous that Alfa's set up doesn't allow for more negative camber. We run -4.0 on our race cars...I'd think you could get -1.5 for street. Is there a better answer than adding shims?
 

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so you have less than 1 degree of negative camber on the fronts? it's a little ridiculous that Alfa's set up doesn't allow for more negative camber. We run -4.0 on our race cars...I'd think you could get -1.5 for street. Is there a better answer than adding shims?
I had wondered the same thing, since a few posts indicated people with the ”fast road” (formerly “intermediate”) suspension blocks had 1.5deg negative front camber. How? My local shop is trustworthy, and I don’t doubt that they shims were max or close to it. That said, for longevity of tires i don’t know that more than 1.5 would be needed— but another half degree up front seems like it could help. Car drives good on the road right now and I won’t do but maybe one track day a year, so I’m ok with it as-is i suppose.
 

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I had wondered the same thing, since a few posts indicated people with the ”fast road” (formerly “intermediate”) suspension blocks had 1.5deg negative front camber. How? My local shop is trustworthy, and I don’t doubt that they shims were max or close to it. That said, for longevity of tires i don’t know that more than 1.5 would be needed— but another half degree up front seems like it could help. Car drives good on the road right now and I won’t do but maybe one track day a year, so I’m ok with it as-is i suppose.

I'll be installing these myself in the next few weeks so I'll see what numbers I end up with too
 

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I had wondered the same thing, since a few posts indicated people with the ”fast road” (formerly “intermediate”) suspension blocks had 1.5deg negative front camber. How? My local shop is trustworthy, and I don’t doubt that they shims were max or close to it. That said, for longevity of tires i don’t know that more than 1.5 would be needed— but another half degree up front seems like it could help. Car drives good on the road right now and I won’t do but maybe one track day a year, so I’m ok with it as-is i suppose.
My race shop has a pretty competent reputation and was only able to get to about -1.7 front with the race blocks. Caster was around 4.2 I think. Seems like there is some variability in what different cars can reach without shaving things down here and there. For what it’s worth I’m running -1.7 front and rear at the moment with the GMS Alfaworks rear arms and alfaworks front rose joints - which are both great.
 

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Discussion Starter #6
@neth thanks for the feedback — do you have the factory standard or race suspension, or something else/aftermarket? and what year is your car?

For reference Mine is:
2015 Launch Edition
OE Race Suspension
Intermediate/“Fast Road” Blocks
-0.99 front camber

I’m curious to hear which suspension you have. I also think I had read that the Race blocks have more camber but less caster, inherently? Not sure if that is true ?
 

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@neth thanks for the feedback — do you have the factory standard or race suspension, or something else/aftermarket? and what year is your car?

For reference Mine is:
2015 Launch Edition
OE Race Suspension
Intermediate/“Fast Road” Blocks
-0.99 front camber

I’m curious to hear which suspension you have. I also think I had read that the Race blocks have more camber but less caster, inherently? Not sure if that is true ?
I have a 2018 coupe with race suspension, stock except for:
  • Alfaworks race blocks (work great for me on my non-tracked car)
  • Alfaworks rear arms (oops said they were GMS in earlier post)
  • GMS engine mount - shifts are smoother
  • Custom wheels
  • 215/40 18x8+29 and 255/35 19x9.5+34 conti extreme sports (compromise for seattle weather but would prefer RE71, probably when I get another set of wheels later on)
Alignment is -1.7 front and back and a smidge toe in front and a bit more toe in back. So far it works well for me.

Hope that helps.
 

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Discussion Starter #8
Thanks again @neth love having various data points. So the biggest delta between our cars would be the Race vs Fast Road blocks, and this would match what I thought re: camber. I ended up with +4.42deg caster so if you have that info to add to your reply/edit above post that’d be great. But either way it does perhaps “maybe” confirm what I had read elsewhere that the race blocks are also camber-heavier than the road-blocks.

Good data about the rear arms as those are on my wish list down the road, but lower priority. Other stuff we differ would not impact camber/caster settings. Again, thanks — drive safe & enjoy!
 

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Thanks again @neth love having various data points. So the biggest delta between our cars would be the Race vs Fast Road blocks, and this would match what I thought re: camber. I ended up with +4.42deg caster so if you have that info to add to your reply/edit above post that’d be great. But either way it does perhaps “maybe” confirm what I had read elsewhere that the race blocks are also camber-heavier than the road-blocks.

Good data about the rear arms as those are on my wish list down the road, but lower priority. Other stuff we differ would not impact camber/caster settings. Again, thanks — drive safe & enjoy!
No problem :) I’ll update the post above as well. With race blocks my caster is around 4.2 if memory serves me.
 

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My race shop has a pretty competent reputation and was only able to get to about -1.7 front with the race blocks. Caster was around 4.2 I think. Seems like there is some variability in what different cars can reach without shaving things down here and there. For what it’s worth I’m running -1.7 front and rear at the moment with the GMS Alfaworks rear arms and alfaworks front rose joints - which are both great.
Same as me, just shy of -1.7 camber, caster about the same as me. Race blocks.
 

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Intermediate blocks + shims here. I'm also lowered on Eibach springs.

Only able to get -1° camber in the front, 4.7° caster, zero toe.
Rear is -2° with slight toe-in (0.15").

I like how it drives, especially on the interstate, but the steering effort is definitely there. :D

@Shaka your front toe-in might be adding to the understeer and delaying your turn in from my limited suspension knowledge.
 

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Discussion Starter #12
You are 100% correct @dhuang — the slight toe-in does make the car less swift to turn-in ... but it also makes the car less likely to wander. So it becomes perhaps a bit of a quandary. If i went down to zero toe perhaps I’d get crisp, sharper turn-in ... but i’d have that ALL the time, meaning even when driving straight the car would be more willing to change direction. My understanding and hope is that the sway bars should flatten the cornering, providing more rotation When I actually want it (with steering input) versus the sway bars should have very little negative impact when driving straight. We’ll see how it goes!
 

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You are 100% correct @dhuang — the slight toe-in does make the car less swift to turn-in ... but it also makes the car less likely to wander. So it becomes perhaps a bit of a quandary. If i went down to zero toe perhaps I’d get crisp, sharper turn-in ... but i’d have that ALL the time, meaning even when driving straight the car would be more willing to change direction. My understanding and hope is that the sway bars should flatten the cornering, providing more rotation When I actually want it (with steering input) versus the sway bars should have very little negative impact when driving straight. We’ll see how it goes!
That (zero toe) is a compromise worth having. You also get less adverse wear on the inside tyre edges. So what if you have be a little more alert on the motorway. Sharp turn-in is worth it. You know my settings. No need to repeat them.
Many have masked their 4Cs handling characteristics by fitting wider and stickier tyres. I’ve kept the Pirellis and tried to get Rosie working as best I can on her standard suspension and on those average tyres. For me zero toe is the best compromise...Again. for the record, my second set of Pirellis seem way better than the ones she came with. They aren’t as good as the Michelins but not nearly as bad as some make out (who probably haven’t spent the time experimenting with settings and adding uniballs).
 

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FYI, tramlining in my case was solved by 16mm rear spacers. Tried toe in etc with no luck.
 

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Discussion Starter #15
@Alfanut -- some of this is also subjective. As noted in my prior replies, it also comes down to driver confidence. We can objectively all observe a car doing the same thing, but how that impacts one person to the next is subjective. Same could be said about tire wear-- objectively, we can agree what might occur, but if that is worthwhile or not becomes a more subjective matter. For me, I'd rather have less "twitch" on the freeway, even if it means less direct steering on the side streets, since 25% or more of my driving in this car will be on the expressway. For those who trailer their car to the track, and only see glassy smooth road course pavement, the opposite may be true. And that is just 2 examples of hundreds (or in the case of 7500+ built, thousands of 4C owners) ;)

@AAaF that is interesting to read. I had thought about doing 15-20mm rear spacers purely for aesthetics, but had also considered the fact that it would add the potential of a bit more forward push, and also potentially increase the throttle steer capabilities. Alas, I returned the spacers I had bought and never used. So not sure I'll go down that path again anytime soon.
 
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