Spring Rates Classic Revival

Churchy · #1 (**permalink**) 07-26-2005, 07:16 PM

Nearly at the stage of shocks and springs, and was wondering what spring rates for the CR. Ian reccomends primary of 525lb/in and secondary of 450lb/in, and primary of 450lb/in and secondary 450lb/in for front/rear. Can't remember which is which, I have got the onfo at home.

We are going to be having a pretty stock CR build. Ford rear, Jag front, LS2 and Tremec T56. It won't deviate to wildly from Ian's spec's.

I am of the opinion of keeping it simple, so probably a single rate spring, (less for me to bugger up)

.

Thanks for the advice there Phil.

Probably going to grab them from Demon Tweeks in the UK, as they seem to have the cheapest prices, even considering freight and duty. So I want to ensure I get the order right when ordering springs.

So any thoughts, experiences or advice would be most welcome.

Or even a little sledging ..

Leeroy · #2 (**permalink**) 07-26-2005, 08:12 PM

Churchy
I got my springs/shocks from Ian and got what you have stated also. I found the fronts very hard around the streets and didnt like the rock hard ride. I have put 350lb main spring (is that the primary?) and it is much nicer to drive around town. I think I will end up using the 450lb for the track though but will wait & see what the later ones handle like.
Cheers Leeroy

boxhead · #3 (**permalink**) 07-26-2005, 10:24 PM

I to fitted the springs as recomended by Ian, I havent driven my car yet but I have found the front feels very stiff (ie cannot bounce it) and the rears seem very soft (ie doesnt take much to get the back to squat)
On a side note I have moved my rear lower shockie mounts further inboard than recomended (so I can fit wider wheels)
I have fitted primarys as recomended and very short secondries at 125 lbs (so it will be easier to adjust ride heigt)

Tenrocca · #4 (**permalink**) 07-26-2005, 10:49 PM

Couple of questions I have as well (I know nothing about shocks\spring rates etc except the bleedin obvious by the way).

* What is the advantage of having a primary and secondary spring over a single one?

* Do you need all the suspension travel the suggested AVO's offer. Ive been lookng at QA1's which work out a little bit cheaper and are rated pretty highly as well, but the closest size they make in a similar spec shock is a 10 - 14" compressed\extended size. With those Id lose 1" droop on the front at the mounting point (a little more at the wheel) and 2 inches on the rear. If the shock mount was moved further inboard on the rear as boxhead and Mike have done, would that mean you would lose less droop?

* What is the recommended ride height for the CR? (Is there one?)

* David, I know you used spax shockies. What sizes did you use?

Cheers.

Churchy · #5 (**permalink**) 07-27-2005, 04:12 PM

I have been for a ride in Phil's snake (what a blast) and I reckon if I can get mine close to that I am going to be very happy.

From my understanding of springs (which is very limited), the rates are how much pressure it takes to compress the spring by one inch. So if that is the case what does the secondary do ?

Is it necessary to have the second spring, or because this will be a "not racing in Le Mans" car, is just a primary rate OK.

Leeroy, did dropping the spring rate drop the ride height and did you do this prior to, or after rego. I want to make sure we pass the 140 mm ground clearance at engineering ?

Leeroy · #6 (**permalink**) 07-27-2005, 04:37 PM

Churchy
the ride height is adjusted by the perload of the spring (the amount you wind in the ring) Still not to sure about all this as when you are happy with the ride height (preloaded springs) this also has influence on the way the car rides & handles so it seems to be something which takes much experimenting. Fortunately with the prim/sec. springs it has a spacer between them (Ian provides a useless nolothane ring which I have replaced with a machined nylon spacer which gives greater gap & less chance of springs binding each other & shock as Ians ones proved to do. This spacer you can increase/decrease the gap which will allow you to get the correct ride height & spring preload. As earlier I too am not sure as to why prim/sec spring but perhaps this is a good reason to do it this way?? Spacer goes for both front & rear.
Leeroy

boxhead · #7 (**permalink**) 07-27-2005, 10:29 PM

My secondary springs are of such a light weight that they compress fully with the car just sitting on the ground.
The reason I have used this is so when I wish to change ride height (by raising or lowering the 2 nuts on spring) I am only trying to comress a 125 lbs spring as opposed to 500lbs.

jess · #8 (**permalink**) 08-01-2005, 04:41 AM

hi guys
apparently the small spring only works when the wheel is about to leave the ground or when it's about to make contact with the road surface after lift off, you would need to drive the car preety hard for this to occur also found the avo shocks pretty hard once you get past the 3rd adjuster this is just an observation my car is nowhere near compleate the suspension has to work otherwise all the impact will be taken up by the rims and the car will tend to oversteer and not handle the way it should yet if anybody out there has the ride height specs ie: centre of hub to top lip of guard and some wheel alignment specs for the classic revival this would save a lot of time unfortunatly every time you chance the ride heights you must get an alignment front +rear so its not something you want to do to often
jess

pneall · #9 (**permalink**) 08-01-2005, 03:49 PM

Jess,

This is set up I am currently running on my CR.

Front Camber: -1.54, Castor 4.1 Toe 1.0

Rear Camber -1.1
Rear Toe 0.0

Chassis Height Front 185mm, Rear 200mm.

Getting the suspension "right" had the single biggest impact on making the Cobra feel good on the road. The smallest change in rear ride height impacts dramatically on the rear settings.

As you said its expensive excercise every time you make an adjustment.Took me about $300 to get here and I am planning lowering the ride height next week.

I am not saying this is ideal settings but itsa good start point.

The JBL site has some good info on suspension set up.

Phil

Only 59 sleeps to the Nationals

Churchy · #10 (**permalink**) 08-01-2005, 04:20 PM

Phil, did you go with Ian's standard spring rates. I seem to remember when Pete and I came up that you mentioned that you either changed from Ians reccomended rates or were about too.

Or was I hearing things ??

Geez, I am learning sooo much, and I have not even got anywhere near engine or drivetrain yet

pneall · #11 (**permalink**) 08-01-2005, 04:37 PM

Churchy,

Yes I did change the rear springs but that was because Ian originally supplied me with front springs for the rear. He swapped them over no charge.

So the short answer is that Iam using springs as recommended by Ian.

Only change I made was to machine up aluminium spacer to go between the two springs in place of the neoprene spacer that tends to extrude.

Phil

PS did I mention there is only 59 sleeps to the Nationals.

Churchy · #12 (**permalink**) 08-10-2005, 11:27 PM

Got the AVO shock absorbers, they are nice and shiny. Will have a lot of fun bolting these bits on.

Still trudging through the the spring rate minefield, and lots of things keep blowing up. Spoke to the guys at King Springs, and he asked me even more questions of which I have no idea.

I need to do a lot more research prior to ordering springs

Signed *very confused Shock Absorber owner*

Leeroy · #13 (**permalink**) 08-10-2005, 11:47 PM

Dear very confused Shock Absorber owner,
I finally got my car aligned last week and I am very happy with the result. As earlier stated I have same AVO's as you and fitted 350lb front & 525lb rear and it really handles and drives well. Drove over to Aussie Mikes on Sat. and it seemed very soft in the rear with both of us and tended to wollow at bit (I should loose some weight Mike) It was set very soft on the rear and after a couple of dial ins clockwise to harder it is now perfect . I think you could go with the same rear as me as the fronts on mine at this stage are 3clicks off softest setting and you would have a pretty go starting point to work with.
Leeroy

Churchy · #14 (**permalink**) 08-11-2005, 12:07 AM

Hey Leeroy,
Thanks for that mate. I have completely forgotten, do you have primary and secondary or just single rate springs ? My brain has gone blank due to spring induced punch drunkness.

King Springs said I need to find out the ID, the free length and the spring rates (the later I have). Do you have the specs from when you ordered yours from King Springs ?

Leeroy · #15 (**permalink**) 08-11-2005, 12:27 AM

Fronts are now King springs KPS.025. They are 8"long with a wire dia 0.5" and I.D. of 2.25". Yes I have prim/secondary springs but only have changed the primary (main spring) Rear as earlier mentioned in thread

Aussie Mike · #16 (**permalink**) 08-11-2005, 06:05 PM

Leigh,

Thanks again for the drive, I'm trying to cut down on the Pizzas and hamburgers.

Did adding a few more clicks to the rear shocks make much difference?

Cheers

Leeroy · #17 (**permalink**) 08-11-2005, 06:21 PM

Mike
whats life without a little indulgence once in a while.

After your 3 clicks in it still had a tendency to wollow, so I stopped and went in 3 more and it was perfect. Interesting that the front is only 2 clicks off softest. I haven't played with that as still pretty happy with the way it is now.