308 Chassis Diagrams

Mine is on a lift while I work on the wheels, suspension, and brakes. If you need a specific photo and/or dimension, send me a PM.

 

While we’re on the topic - does anybody have full suspension tech specs for the shocks? Suspension motion ratios, lengths compressed/extended, stroke length, etc. I can’t find these, especially would like the motion ratios.

 

Morning Tony,
308 QV and 328 GTS/GTB use the same chassis. Don't know about previous 308. Never the less, I'm sending you diagrams on these chassis.
Hope this helps!

John.

 

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Tony, I found this on internet, "Ferrari documentation, technical specifications"

John.

 

Now that you're starting from scratch, you may want to use a better steel. Original steel used on 308 and 328 is mild and if the car is a targa top it's not very sturdy.
You might want to contact Martin on this subject, he's a mechanical engineer and could give you advice on selecting proper material.
Martin has a 308 and has many posts on this chat.

Hope this helps, good luck!

John.

 

Not exactly true: the "serie 2 328s" (the car with bulged wheels) have different geometry of the four pyramides of tubes for suspension anchoring.
(And different suspension members at the front; different wheeltrack, offsets, half-an-inch shorter wheel base, etc...)
Rgds

 

Afternoon,
Well, that's useful info. Good to know, I have an 87 328 and I know for certain that front and rear alignment geometry is different than on the 89 model.
I supposed it was the same chassis and geometry was altered with shims.
By what you're saying the A arms are anchored at different points... that's a lot of redesigning and modifying, specially if it's already on production.

Thanks, I always learn something new.

John.

 

Afternoon Tony,
By what I'm reading, I consider that you will have to gather a lot of info on your car, like production year, VIN and what market was it made for initially.
You're not aiming on fixing, you are "building" a chassis...Hell of a task!!!

Good luck!, I'm sure you can make it happen.

John.

 

"if the car is a targa top it's not very sturdy."

I haven't noticed much flex-- is this a known issue with the targas? If it is then changing the material won't make much difference as the mild and alloy steels have similar moduli of elasticity. Better to change the design (more or bigger tubes.) Unless you are racing and want to reduce crash damage, mild steel has the advantages of being tougher (deforms to absorb energy) and easier to weld than the chrome-moly steels used for a racing chassis. I've had parts made in 4140 and 4340 and they rust if you just look at them.

 

John,
The front suspension of the "serie 2" cars (bulged wheels) is in fact exactly the same as the one of the contemporary "Mondial": all parts ("A arms" etc...) are interchangeable. Said to be for ease of parts procurement, but also allowing ABS installation. The chassis is the same horizontally (ladder of tubes) but not the four pyramids holding the suspension anchoring points, which have a different geometry, to the extent that a new certification process was required: "Serie 1" GTBs are "F106 AB/R", "Serie 2" are "F106 AB/PB". See diagram "M9" in the WSM ("from chassis #76626 onwards") for instance.
Rgds

 

there are differences between the 308 and the late 328 were the pick up points are relocated. primarily in the front end were geometry changes are significant. the later uses longer mondial arms to move hub-faces outboard for a more modern wheel offset and geometry set up. this location to reduces scrub radius, steering effort and kickback. it share the same steering rack and uprights as the mondial and possible the 288gto on the steering if memory serves.

its worth noting the A-arm aren't not parallel in side view which alters the instantaneous center for anti-dive set at 6-7 degrees or so from the top of my head. this in addition to added caster angle and relocated steering axis may have shifted the static wheelbase rearwards to account for the increase fore/aft displacement of the wheel through its full travel within the wheel house.

best regards

 

The motion ratios (wheel deflection vs spring length deflection for a modest wheel deflection) for the suspension geometry in the 308GT4 WSM (and I believe 308B/S are the same or very similar) is shown in the drawing in post #5 of this thread:

https://www.ferrarichat.com/forum/threads/front-nose-high-stance-will-new-springs-cure-this.504766/

The nominal spring lengths (with the chassis on the ground) is also shown in the 308GT4 WSM IIRC.

 

Thank you, Steve, that is exactly what I was looking for (and had not been able to find with lengthy searches!)

Cheers,
Gordon