Coilover suspension upgrade (BiTurbo)

[A.S. Motorsport]

Thanks for the quick reply. As you say the car definitely dives on moderate braking and suspension is a soft, tilting on the corners. But the turn is neutral (doesn't oversteer /understeer). It's also a 2.0lt biturbo and one of the last pre-evos if that makes any difference (maybe a little on weight?)

So from your comment I understand that the suspension behaviour is what it is. Would you have more details around that sway bar you mentioned?
Would you recommend stiffer springs?

The setup as we've set it up now in for the Coupe's is harder and for the Sedan's is softer.
Off course we can easily increase spring rate if you'd want a QPIV V8 to be stiff, but personally i'd say that defeats the purpose of a QP4

During testing here on 2.24v we got it to the point of being natural and comfortable using stock sway-bar front and no rear.
This would off-course also scale out to Ghibli etc which would benefit from there much improved swaybars and geometry.

Also, for Ghibli and QP4 we've added adjustable end-link mounts, which is required for them as when lowering you'd want to be able to setup the installation height of the end-link versus shock.

Regarding the stiffer sway-bar, the sloppy turn in of QP4 especially V8 is due to the tiny stock swaybar we have enlarged front bars to compensate.

 

[alpa]

Regarding the stiffer sway-bar, the sloppy turn in of QP4 especially V8 is due to the tiny stock swaybar we have enlarged front bars to compensate.

That's great to have larger front sway on QP4. They are definitely too thin.

Yes on QP4 and especially EVO tires touch arches depending on the tires and rims.
The neutral turining behavior of all 5 bolt biturbo is due to a very high caster angle and to a double lever steering mechanism (which makes similar to the steering boxes setup). Both make cars very stable at high speed and less sensitive to road bumps (less steering bump). The negative points are the use of needle bearings in the steering lever that is never checked until the car becomes undrivable in straight lines. And that front tires stick so well that the chassis does not cope with the efforts and bends, even on Ghibli GT. QP4 are less prone to these problems.

 

[A.S. Motorsport]

That's great to have larger front sway on QP4. They are definitely too thin.

Yes on QP4 and especially EVO tires touch arches depending on the tires and rims.
The neutral turining behavior of all 5 bolt biturbo is due to a very high caster angle and to a double lever steering mechanism (which makes similar to the steering boxes setup). Both make cars very stable at high speed and less sensitive to road bumps (less steering bump). The negative points are the use of needle bearings in the steering lever that is never checked until the car becomes undrivable in straight lines. And that front tires stick so well that the chassis does not cope with the efforts and bends, even on Ghibli GT. QP4 are less prone to these problems.

Well that the sloppy shock layout internally and the top mounts aggravate a lot of the issues, also the fixed camber geometry doesn't help.
GOC cars had offset mounts, QP4 had thicker rubber top bushings but the odd angle of the setup (shock vs spring vs chassis) creates a lot of room for issues in aging and play to start.
I recall GOC EVO had spherical bearings in very very large cnc top mounts to finally solve the issue.

Hence we use spherical bearings in the top-mounts and full camber adjustment becomes possible.

 

[alpa]

Well that the sloppy shock layout internally and the top mounts aggravate a lot of the issues,

Do you mean the cartridge inside the strut tube ? I've never tried to explore how strong it was all fixed. I dismounted one destroyed strut from QP4 to see how the adjust system is made. Described on the Enrico's pages.

also the fixed camber geometry doesn't help.

Isn't it the nature of a McPherson ? Many performant cars had and have McPh (including modern WRC). It's simple and strong.

Hence we use spherical bearings in the top-mounts and full camber adjustment becomes possible.

Wow that's good ! I'll definitely buy for at least one of my biturbo.

 

[A.S. Motorsport]

Do you mean the cartridge inside the strut tube ? I've never tried to explore how strong it was all fixed. I dismounted one destroyed strut from QP4 to see how the adjust system is made. Described on the Enrico's pages.



Isn't it the nature of a McPherson ? Many performant cars had and have McPh (including modern WRC). It's simple and strong.



Wow that's good ! I'll definitely buy for at least one of my biturbo.

Often McPherson does have camber adjustment, for example ether in lower control arm mount (if it's a triangle setup) or shock to spindle mount with eccentric mounts
As for use in "performance" no it just cheap, hence all later and earlier Maserati's use double wishbone, any purpose built race car or supercar would too

 

[alpa]

Porsche kept McPh for a very long time. And look at the WRC suspension McPh all over.
I'm not saying it's the best, I'm saying it can be good if properly adjusted.

You are right it's actually common to have uneven botls on the hub to adjust camber. I remember now having projected to do that on biturbo. But I finally just made a WRC like tubular arm with a replaceable U-joint under the hub.
Biturbo 5 bolt (not Ghibli/QP) have also a huge weakness on the alu arms where the main U-joint is inserted. Arms can crack when a joint is replaced by an average mechanic that uses a 20T press. I had both arms broken on my 2.24. Well it's a different discussion.
I was just thinking that if you could also develop a better arm system it'd be good. But I understand the market isn't large enough.

 

[alpa]

• Full ride height adjustment (independent of spring preload!)
• Full spring preload adjustment (separately form the ride height)

Could you explain more: does this means there are adjustable stops on both ends of the springs ? I don't see them on the pictures.
Oh wait it's for the front only, right ? The small sleeves are screwed on the struts ?

I understand that in the choice of springs you targeted a firm ride with coupe and softer with sedans. Do you have firmer springs in case I want to use them on a lighter track days car ?

 

[A.S. Motorsport]

Could you explain more: does this means there are adjustable stops on both ends of the springs ? I don't see them on the pictures.
Oh wait it's for the front only, right ? The small sleeves are screwed on the struts ?

I understand that in the choice of springs you targeted a firm ride with coupe and softer with sedans. Do you have firmer springs in case I want to use them on a lighter track days car ?

Correct the spring perch is separate from the spindle mount, we specifically do this so you can select preload on the spring separately from ride height AND can maintain same spring load on a lowered car.

As for harder springs, yes no problem it modular i can do pretty much any weight.

See picture:



Detailshot of the spherical bearing and camber adjustment:

As you can see the camber adjustment slots are designed to give max range with in stock strut towers,
Also for those running Ghibli Cup style strutbraces there is ample thread on the mounts,

 

[alpa]

That's brilliant !
Is spherical bearing steel-to-steel or is there any PTFE kind anti-friction layer ? Wouldn't the bearing require a protection boot ?

 

[A.S. Motorsport]

Extra detail shots, we're now taking preorders for the second production batch (first batch just in from CNC and sold out)

Ghibli/QP4 kit



Rear shocks, adjustable lower body for height, spring perch is adjustable for preload and secondary height.
We've chosen for rubber lower and upper mounts to reduce noise from the rear axle, something all Maserati's are very prone too.



Front shocks for a 2.24v/2.22/4.24 etc, no sway-bar mounts on these as this is in the control arm, for those interested in replacing that, we can accommodate it by supply Ghibli style adjustable upper swaybar mounts (you'd need endlinks and QP4 or Ghibli swaybars)


Again adjustable lower body for height, spring perch is adjustable for preload and secondary height.
Clearly shows the adjustable mount for sway-bars on Ghibli and QP4, you can align the end link after setting ride-height.


This shows the large camber adjustment range, this is front shocks, there even is a provision for a extra adjustment if it's needed.
Slots are maximum that the Maserati chassis top-mount allows, this should be more than anyone would need in adjustment.

 

[alpa]

Excellent !

 

[A.S. Motorsport]

First batch deliveries done, tomorrow the final sets should be arriving at customers farther away per courier, (Sweden, Finland, Germany)
We'll do the second batch January

 

[henris42]

Merry Xmas! I indeed received one of these kits just before Xmas, and it looks really good, and well made with attention to detail!

I'll share my experiences installing and driving later closer to spring, after I've done the engine etc.

 

[Motorsport3]

I will be seriously considering a set for my QP4. Presumably these are fixed rate/not electronically adjustable?

 

[A.S. Motorsport]

I will be seriously considering a set for my QP4. Presumably these are fixed rate/not electronically adjustable?

Yes they have 30 adjustments but that's manual (turn a knob on the shock-tower)
We thought of adding electronic stepper-motors like 3200GT but there is no room in front (bonnet) in the rear the parcel shelf clearance isn't great ether (coupe)

That said nearly everyone that i know drives the koni in mode 3.

 

[Motorsport3]

Yes they have 30 adjustments but that's manual (turn a knob on the shock-tower)
We thought of adding electronic stepper-motors like 3200GT but there is no room in front (bonnet) in the rear the parcel shelf clearance isn't great ether (coupe)

That said nearly everyone that i know drives the koni in mode 3.

I agree, the soft setting is too soft particularly if you are used to modern cars. It's definitely something to do once I deal with more urgent issues.

 

[A.S. Motorsport]

OK so first customer install's being completed, this a Ghibli at client in The Netherlands

 

[A.S. Motorsport]

We're taking orders for the second production run!

 

[general_piffle]

So, what happens to the little 1/2/3/4 panel in the Ghibli cockpit to adjust suspension? Does this simply become redundant and no longer light up or do anything?

 

[A.S. Motorsport]

It lights up and looks fine, but it doesn't control anything anymore. (the whole car looks pretty much factory stock besides the ride-height and in front you can see the camber adjustment if you look closely to the strut tower tops)
We did quickly look-into making actuators to fit on to the shocks, but that's in front problematic in bonnet clearance.
That said nearly all customer with the system working drive in mode 3 of the koni.

The system handles so much more precise that you'd setup shocks to your liking and just leave it, that here in testing is between setting 11-15 (of the 32 adjustment settings)


FYI adjusting front suspension is less than a minute job as you just turn the knobs in to softer or harder, rear you'd need to remove the parcel shelf to access after completing a install