QA1 Vs. Penske !!!!!!

Stroker-427

Well-known member
Joined
Mar 23, 2008
Messages
315
Location
Pistoia - ITALY
Ok guys..... this is not a really "apple to apple" comparo, but what a difference!!!!!

Today I test drive my C3 with new Penske 8300 coilovers (QA1 are now in the shelf....) and it is an othe planet!

With my 1000 lbs springs the double adj. QA1 where not able to control the spring force..... I was forced to set the knobs nearly full stiff, and the result was a very stiff sistem for the low speed (talking about the suspension not the car..) but the shock was loosing control in case of a little higher speed.

So the setting was too "squared" without any digressivity..... too stiff at the beginning, loosing too much control under higher stress.

The car was pumping at the apex of the corners and coming out when accelerating strong.

Now, with the Penske, I can go many time more soft at low speed and I still have a lot of control of weight transfer.
:yahoo:
Very very good move..... if you need some more that a cool look under the car!!!!

Of course a bit pricey (some 800$ each) but, you know, the more you spend.... the less you spend!

Nice work Penske guys!!!!!

P.S.
The guy of Penske was very competent, in order to select the correct valving he asked to me infos on springs, spring ratio, corner weights and
suspended and not suspended mass of each corner.
 
Penske 8300 coilovers

Good-day My Italian Brother :

I Know this thread is 3 years old but ...would you have the part number for those Penske 8300 coilovers? I think you said they were 11 Inches long?

I studied your photos for the Shock mount and think I can replicate it. Also measuring for clearance of the body panel... C2 1963 compartment's a little different. Thanks so much for all the help and advice on the suspension build
 
Hello Sting...

Penske will not sell off shelf shocks, but you will need to send a lot of infos:

1) sprung weight
2) unsprung weight
3) load ratio on the coilover
4) average use of the car
5) stroke of each suspension
6) spring ratio used

Yes in my case the shock are the 11.5" long extended and 8.5" compressed

My contact Richard Scott was in UK (because I'm in Europe)
I think you should contact Aaron Lambert [email protected]

Let me know......:thumbs:
 
Thanks Pier Paolo :

I ended up ordering a pair of Bilstein "sport" coilover's that are approx the same size as yours. I'm feeling good with Bilstein's Quality and they can be re-valved if necessary. Of-course price had some pull on this decision. Now get to working on the upper frame mounts. :eek:
 
#2 Questions

I appreciate the fast reply, two more questions :

I have a choice of Heim Joints or Urethane bushing mounts. I was thinking , wound there be that much camber change to need the Heim ? Also I have see some coilover's mounted up side down (Spring on bottom// Shock valve body on top ) Good Idea for a gas shock ? Perhaps it's just for clearance reasons? Bilstein show's them that way in their ad? Thanks Again Bud

http://cart.bilsteinus.com/pdfs/Streetrod.pdf
 
In my opinon heim joint are the way to go..... specially if the shock will be pretty stiff !
Any gas shock can be mounted up side down..... twin-tube shocks (like QA1 for example) cannot be istalled up side down.


In fact a gas shock must have a floating pistone inside the body to separate the gas from the oil, thanks to this you can do that.

A good reason (in light cars) for an up side down mounted shock will be the reduction of the unsprung mass.

In our cars the unsprung mass is so big that it will make very little sens.
 
Shocking

Once again
Thanks for the info. my friend. Things are finally coming together. Dang .....If I jest get the car together ......Maybe Ill stop making these crazy design changes. Sadly, I have enough leftover parts to build a whole other chassis (Seriously)! :confused2::thumbs:
 
Strut Rod's length

One last question:

I see your Strut Rod's used on your set up are VBP smart strut items. Im buying regular threaded Rod from Speedway. Would you have the length measurements for the Upper rod's & toe rods ?
I remember discussing the Camber arc requires the upper to be 30% shorter than the lower. My lower rods are at minimum 15 inches so .. -30% would be 10.5 inches. Correct ? I have no idea where to start with the toe rod length. I Appreciate the help.
 
Yes, the upper rod must be shorter for camber gain.
Remember that this must be related to the roll stiffness you will design in your car.
The more roll stiffness you have, the less gamber gain you need...... the limit is zero roll, in this case you will neet the amount of camber gain to correct only the tire wall deflection.

In my setup I have the lower rod 20% longer than the upper rod.

Now I can't give you the correct measure.... but Tomorrow I will !
 
Ok got it. 12 " Eye to eye for upper rods. I had extra pair of anodized aluminum tubes that would work, but I think it would be best to go with a full set of steel tube's. Your thoughts?

Lastly... What is your measurement (toe) adjustment rods ? Thanks :eek::blush:
 
I would go with steel tubes!... there is a lot of forces involved!

The toe rods are 13.5" (average between the two Others rods).

Did you allready assemble the system in your car?
 
On a Mission

Well brother:
It's time for this 50 year old car to be on the road. I have a mechanist friend making the 18 assorted spacers needed for the heim joints, then bolt it all up. The coilover spring mount I copied from your photos. It will be a tight fit. Seems everything has to be custom fitted by hand. I'll have photos for you guys shortly, when its all together. Thanks again for all your support. ;):bounce:
 
Good-day Mr. Pier-Paolo Lucaroni

Such a undertaking this has been....But now coming together with Parts and the Time to assemble them. I have another of the 1000 questions we have ask you over time .... On your parking brake (emergency Brake) Cable, the anchor bracket must be bolted to the upper rear link Bolt ? Not welded? Seems a piece of 2 inch angle stainless could work. My cables seem too long too (Original Drum brake 63 style) . Might have to chop them up. :search: Never really saw a photo of your e-brake cables attached. Have a good weekend mio fratello ...... G.R. Annoni
 
Hi man,
of course you never seen my e-brake cable..... I have hydraulic e-brake working in the main calipers.

not very good for parking.... but is very fun for drifting..... :cool:

So you will need to do some DIY bracket if your cables are longer.

Ask me all the question you need..... don't be afraid of that!!!!
 
Coilover Spring selection

Pier Paolo;

Good-day my friend : I wanted to ask your advice on spring rate for the 6 link. I'm reading different rates you used in your posts. Using the formula for a approx. 28 Deg angle for the shock. I figured 650 lbs springs. Tried to order them, but company now only carry 550 600 700 800 lbs. Car will weigh around 3100 lbs. wet. I'm thinking 700 lb.?

Thanks GRANT
 
Hi Bro,

First of all I need to know the stroke of your shocks, because this will really have a big influence on spring ratio.

For example, for road racing, this is wath you are looking for:

1)your car should sit with around 40% of sag.
2) The spring preload should be as low as possible

In my case I have 2.75" of stroke at the shock, and a spring factor very close to 1:1.
The car have near 850 lbs of load on each rear wheel
If you do some simple calculation, you can check that for 40% sag I need springs close to 850 lbs/inch load factor.

If you car have the same wheel load and 4" shock stroke, your sag should be in the range of 1.6" (40% of 4").
850 lbs / 1.6" = 531.25 lbs/inch spring ratio (assuming you have 1:1 spring to wheel ratio)

Of course the spring ratio must be multiplied by the spring to wheel ratio.
For example if your coilover is 30° from the vertical, you will have 0.86:1 (cosine of 30°) spring to wheel ratio and you will have to divide the theoretical spring ratio by 0.86.

531.25 / 0.86 = 617 (650 will be correct)

So, if I was clear enough, the stroke of the shock is one of the most important thing.

Remember that tha stance of the car you are looking for must be achieved with the correct shock sag.

Remember that the shorter are your shocks, the must important are the rubber bump stops.
In my setup I have some 1.6" of bump stroke avalaible, and the bump stops star to work after less than 1" of bump.
In this way I can have a sort of progressive device helping the springs under very high loads (hard acceleration, corners, curbs etc...) avoiding
 
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