[The Dark Side of Will]

Looking at the common setups,
300/250 = 1.2
350/300 = 1.166
400/350 = 1.14
450/400 is 1.125

Remembering back I think
Front = 6.0/3.5
Rear = 6.0/5.5

I think.

But obviously there is more to it than just that as the springs also affect the f/r weight transfer and roll stiffness. I think the ideal f/r ratio is around the 1.8 to 1.2 point....but that's fro the way I drive so.......

Thanks! I figured you already had the info :thumbsup:
If I understand your correctly, for 6" of front wheel travel, the spring travels 3.5"?
I didn't think that the angle of the rear shock was such that the motion ratio would differ that much from 1:1.

Anyway...
For the spring rate combos listed above, these are the wheel rate combos:

Front             Rear   
Wheel Travel  6   Wheel Travel  6  
Spring Travel 3.5 Spring Travel 5.5  
 
Spring Wheel Spring Wheel F/R Ratio
300    175   250    229   0.763
350    204   300    275   0.742
400    233   350    320   0.727
450    262   400    366   0.715

To get the ratio of wheel rates front to rear to be the same as stock with 450# front springs, you'd want a 375 rear spring instead of a 400... or a 475 front spring with 400 rear.

 

[mk e]

To get the ratio of wheel rates front to rear to be the same as stock with 450# front springs, you'd want a 375 rear spring instead of a 400... or a 475 front spring with 400 rear.

Stock for a QV is 180/180,so the front is VERY soft compared to any of the known good combinations.....I'm not really sure what exactly they were thinking there???? but it doesn't work real well.

My next tuning step is probably to drop the rear springs to 375 and add a bit more front sway bar and I think it will be really close to where I want it. I'm tempted to drop the rear to 350 ....that's a pretty big jump though so.....

 

[mk e]

This thread is a great education for me,,,,,why did LD go back to koni? ,,What do you think about putting 350-300 springs on good stock koni,,,47407qv wants upgrade but hes 67 and has limited funds,,as I,,Im 60,,LOL,,thanks mk e,Will and especially Brett

Probably. I tried 350/250 on the stock shocks and it was way better than stock but I thought a touch soft in the rear so 350/300 might be decent...or 350/275.

To get 2.5" ID springs on those shocks I"m remembering cutting off a sheet metal sleeve and making new aluminum lower perches....and and preload is fixed so if you don't like the way it's sitting you need to make another set of perches.

 

[mk e]

Are progressive springs an option? Usually swaybars are just used for tweaking understeer/oversteer after the main springs rates are dialed in.

They probably are but I've never had very good luck with them because the shocks aren't progressive so the shocks and springs are mismatched most of the time.

I used to be pretty firmly in the camp of the springs do most of it and the sway bars tweak...but I've been drifting into the "they both really matter" camp the last few years. Which is really right I just don't know but I think in all things there needs to be balance.

 

[il Capolino]

This is very educational for me, thank you for running through all of this suspension lingo.:thumbsup:

I'm excited to get going on improving the shock/spring situation on my 308 where I find the front end lost in communication.

Thanks again!

 

[The Dark Side of Will]

I used to be pretty firmly in the camp of the springs do most of it and the sway bars tweak...but I've been drifting into the "they both really matter" camp the last few years. Which is really right I just don't know but I think in all things there needs to be balance.

With bars you end up with different different spring rates in jounce/rebound and roll. Just like progressive springs, the dampers can only match one of the possible spring rates.

 

[mk e]

With bars you end up with different different spring rates in jounce/rebound and roll. Just like progressive springs, the dampers can only match one of the possible spring rates.

I never gave it that much thought but that is true I guess.....another reason to try keep the bars fairly soft.

 

[bretm]

Hey Mark, what'd you have to clearance to make the reservoir fit? Front and rear suspension had interference issues?

Also, how far in did you move the rear spring? I assume it was the lower mount on the aluminum carrier that you welded up and moved inwards?

 

[[email protected]]

to give alden eagle some slack. I recieved the shocks back today and visually they did a good job. The shock came with all new adjusting knobs and even new springs so in the end they are probably worth the money. Only the tax bothers me a bit still.


Anyway i will endup now with F/R springs 500/450. (remember i removed a lot of weight from the car ( all together well over 200kg!) but more from the front end.)

together with the new Addco swaybars that are on their way and their adjusability i 'm pretty sure i can end up with a pretty decent setting for the track but again, I still do considder this more a starting point now.

I always believed in the combination of pretty hard springs but reasonable soft shock settings. Basically i believe the spring should do the work, the shocks only real function is to reduced vibration. Playing with bound and rebound adjustability can and will improve things but they will never make op the spring function.
This setup will provide proper corner stability with hard cornering but makes the car still drivable on even a little bumpy track

 

[P2164]

Staven what does your car weigh now? I am still a fan of Alden eagles, I'm sorry about your problems but I know many Pantera's that use them on Road Racing and had good luck with them as I have.

 

[mk e]

Hey Mark, what'd you have to clearance to make the reservoir fit? Front and rear suspension had interference issues?

I'll have to go have a look and take some pics....it was 10+ years ago at this point so my memory is getting foggy. The big problem up front was more about the lower spring perch as I recall and I had to remove quite a lot of material from the A-arm......but I later learned that there was an alternate perch available that would have solved that problem. Basically the spring need to sit as high as possible.

In back there was a slight clearance issue on the upper mount because of the reservoir that was solved by grinding the ears on the frame a touch. The big issue in back was caused moved the shock mounts and I had to cut the snot out of the upper A-arm

Also, how far in did you move the rear spring? I assume it was the lower mount on the aluminum carrier that you welded up and moved inwards?

1.625" if I recall correctly. Yes, I weld up the aluminum carrier and moved the mount in to get the shock to clear the wheel.

 

[[email protected]]

Staven what does your car weigh now? I am still a fan of Alden eagles, I'm sorry about your problems but I know many Pantera's that use them on Road Racing and had good luck with them as I have.

i was probably just unlucky with them. I'm pretty sure they normally perform well or they should have been out of business a long time ago..

I'mnot sure about the weight yet, plan is to have the car weighted when i'm done.

however when i started i had the car weighted and it was about 1400kg
I tried to keep on track with all the stuff i pulled out and or changed and that added up to about 200 kg. This was before the crash and now it's rebuiold with all glass parts it will be even less.
My aim is to endup somewhere around 1100 kg filled.

combined with my almost 300hp engine this will give some shock



btw anyone here experiences with an accu sump on a 308?

 

[bretm]

...I am still a fan of Alden eagles...

I don't think anyone could argue with that. Pretty much any modern shock you'd entertain putting on a 308 is going to be a huge improvement over the stock Koni setup. It's not to say the stock Koni shocks aren't good, but they are 30 years old and are non-adjustable (without removing the shock from the car). I was busting on Chris a bit in his thread about his "girlie" spring rates on the QA1s, but joking aside, that's a fantastic setup and I'd venture it's the best choice from an improvement per dollar standpoint.

The point of the thread from my perspective is to see all the options available, and not necessarily to pick the "best" one as that is completely dependent on our own use cases. What we've seen so far (roughly from least expensive to most expensive) is:
QA1s
Alden Eagles
Penske 7500 SA or DA
Ohlins STJs

The Bilstein ASNs are interesting shocks as well, but cost wise I think you're up into Penske / Ohlins territory by the time they were custom sized, etc. as there didn't look to be any good off-the-shelf solutions.

I'll have to go have a look and take some pics....it was 10+ years ago at this point so my memory is getting foggy...

Hmm... lots to digest there. It'll be great to see first hand what you had to do to make it work.

Even the QA1s require Birdman's paper weights to make the front shocks bolt in without grinding, so it's pretty much par for the course to get a little dirty along the way. The Penskes (with the narrower body) probably wouldn't require grinding up top for the back shocks, but that's just a guess.

...btw anyone here experiences with an accu sump on a 308?

One of the guys on FChat is running an accusump. I haven't posted much over there for years, so I can't remember off hand. From what I remember, he was always happy with it as it cured the low-oil-pressure-while-cornering-to-the-right woe.

 

[P2164]

I think you will have to do a small amount of surgery on the lower control arms in the front as Mark has mentioned, its even been longer than that for my conversion although I do remember doing this to make the Alden's work. Right before we left the Florida Keys I stopped at a FL weight station and got this information regarding weight, I was in the car with over 1/2 tank of fuel so subract out 300 lbs and it comes up to 2740 lbs with all the new brakes new, new shocks, and modifications to the old 208 engine minus the spare tire. Not sure what a US version of a quatro valve weighs but I'm sure its a little more.

 

[duck.co.za]

I can't believe I missed this

:yikes:

Great thread

I managed to find two sets of Penske double adjustable on Ebay . So far I have had a front shock in the car . The rears are to short !! I have two options either buy longer shafts ( expensive ) or machine a spacer as pictured .

I'm building a new addition to my factory . Specifically for my toys , so I can play !!! As soon as I have a roof on it I'll get back to this project .

here are some pic's

The shock with the spring on it ( 450 ) was the one I fitted to the front

 

[mk e]

The rears are to short !! I have two options either buy longer shafts ( expensive ) or machine a spacer as pictured .

The rears want about a 5" stroke......you can't fix that with a longer shaft and those shocks look short to me????

 

[duck.co.za]

Even the QA1s require Birdman's paper weights to make the front shocks bolt in without grinding, so it's pretty much par for the course to get a little dirty along the way. The Penskes (with the narrower body) probably wouldn't require grinding up top for the back shocks, but that's just a guess.


Yes Penske went straight in in the front :thumbsup:

 

[duck.co.za]

The rears want about a 5" stroke......you can't fix that with a longer shaft and those shocks look short to me????

It's been a while since I've looked at this , the second pic is the other set which are shorter ?? But I wanted them for the remote canisters :yikes:

 

[duck.co.za]

Mark am I correct in saying the gas canister on your STJ's is built into the top of the shock ? Making the shock body quite long ?

While having the 5" stroke I need to make the the extended length ( full droop ) longer by using a longer shaft or a spacer on the shaft end to extend the eye ( spherical bearing )??

 

[mk e]

Mark am I correct in saying the gas canister on your STJ's is built into the top of the shock ? Making the shock body quite long ?

yes.

While having the 5" stroke I need to make the the extended length ( full droop ) longer by using a longer shaft or a spacer on the shaft end to extend the eye ( spherical bearing )??

A longer shaft or an extension can make the shock longer but it won't change the stroke most likely...that is really controlled by the body.