CaptainSquirts

iTrader: (3)

When setting up the helper spring. Did you add any preload to it or did it just compress fully when the car is sitting static?

Edit: After researching and learning about shock travel, compression, droop and all that stuff in between how it all works together makes everything easier to understand. So my question I don't need answered anymore. So no I won't need to preload since the tender/helper is a good 300ish lbs so at static it would compress fully at half the weight.

CaptainSquirts

iTrader: (3)

Installed helper springs. Bad thing about the fortune auto coilovers is that you don't have enough shock body/lowering mount to be able to fit the helper spring at full length and have to preload it quite a bit to do so. I still have issues going over certain bumps/railroads/big uneven surfaces where my rear will bounce 2-3 times before it composes itself. Not sure if actually having the helper (which takes 265lbs to compress 1.5") is softening the land when going over those. But it did at least fix my droop issues when going up a drive way and autocross where one wheel would lift off the ground.

MinusPrevious

iTrader: (3)

Tripoding into a steep driveway is normal for a car set up on high rate C/o's IMO. My EvO certainly does that & even my DD which is set-up on Megan C/o's

Your results noted above concern me!

I suggest you run this set-up by Terry (if he still works there) at FA & get his opinion

CaptainSquirts

iTrader: (3)

Honestly I've pretty much not gotten good help. I've emailed and called and it's basically make sure stuff isn't loose. Make sure you have the spring preloaded to instructions. They said it might need to be sent back to them but I really don't want to send them back since I had them rebuilt by them and was like that since day one, also the car is a DD. I bought them used but that shouldn't matter since they were sent to FA for a rebuild before I installed them.

Sent them another email. Hopefully it isn't a level 1 tech support response.

MinusPrevious

iTrader: (3)

Ok, Understand. Glad to hear youve reached out to them.

I would make it a point to request their lead suspension expert. Years ago it was Terry. I would get him on the phone, ensuring he's had a chance to review your tech sheet, & have him comment

Dallas J

iTrader: (1)

I cant tell you what works for your car, you'd need to be able to really evaluate the travels and make sure you have enough compression and droop so it wouldnt be possible for me to tell you where to put things. Though I would probably start with setting the travels without spring and change the ride height with the spring perch in the rear. In my car with the flags and the short main spring I end up having a ton of preload just to get the ride height high enough. New setup with longer springs will change things so I'll re-evaluate.

CaptainSquirts

iTrader: (3)

Yea I did all the measurements before I put in the helper.

4.25" total stroke.
At static, 3.25" compression(2.25" usable due to bumpstops)
1" droop (1.56" wheel rate)
1" bumpstops.

New setup is with the helper
At static, 2.65" compression(1.65" usable due to bumpstops, also corner weight is around 650 lbs so I shouldn't compress more than 1" since 616lb springs.)
1.6" droop (2.5" wheel rate)
1" bumpstops.

I had to preload the helper quite a bit since the FA510's didn't have enough shock body to keep enough threads in the lowering perch unless I lowered the rear quite a bit. Didn't want to do that since it's a little low already and would then have to lower the front which imo is in a really good spot and don't want to throw off the suspension geometry (control arm parallel). So I only got an extra 0.6" at the shock for the helper. If I had a longer/extended lowering perch I would've been able to use a less preload on the helper which might've helper softened it, not sure though...

Dallas J

iTrader: (1)

You should be able to just use a shorter spring to move the perch up. That doesnt effect anything other than where the perch lands and max spring compression with the latter irrelevant to our rear travels.

Also, when you think about the load on the spring, make sure you're subtracting unsprung weight from corner weight. You only care about the sprung weight there.

CaptainSquirts

iTrader: (3)

I don't have issues with not having enough damper body to fit the springs, I have a good extra inch if the helper/main spring isn't preloaded. Its literally the damper body threaded in the lowering perch that I have issues with. Issue is that either the damper body needs to be longer so it can fit more thread into the lowering mount or a lowering mount that is longer so it can allow the damper body to be threaded into it more. I only have about 3/4th damper body threaded into the lowering mount perch. I know I should have at least 1" threaded but i won't make that part the main convo. I called FA yesterday and Matt there suspension specialist was out and said call back today which I'm going to do to see his input.

CaptainSquirts

iTrader: (3)

Spoke to Matt at Fortune Auto. Explained all the things I've tried and he pretty much agreed, something most likely not set up right in the damper. They're going build me a new rear set and send them to me. I informed them that this is a DD and I really don't want to be in a position where I have to take the dampers out so they will send me a pair so I won't have a lot of down time which is awesome. Odd thing they noted from the previous rebuild is that they marked them as the 500 series rather than the 510 series? So not sure if the rebuild was for a 500 series rather than the 510... So seeing if my dampers all around were rebuilt wrong or they could be fine, who knows.

MinusPrevious

iTrader: (3)

Sounds like you did the right thing in getting FA's Tech group involved

CaptainSquirts

iTrader: (3)

FA sent me a new set of shocks for my rear. Installed them and they feel about the same for daily driving. Autocross, they definitely feel more planted. I had issues with oversteer and this actually cured it(now I have understeer at the limits and not over) so something was different compared to the ones I had previously. My guess is for the 510's is that it's normal on certain scenario's where maybe due to the CFD piston on the 510's causing the piston to "blow off" at high speed bumps which makes it act the way it acts . I dunno, just a random guess. At this point I just have to live with it since it's probably just race car things.

Edit update: After driving it more and more, I believe it might be better than what it was for daily driving aspects. Time will tell.

GTA.RS

OP Dallas, I'm about to setup my GTA for track with F650 & R672 springs with mild F helpers & strong R helpers
My way of thinking is jack up one complete side until both SBs limit both droops & the tyres are loaded on the opp side
I'm thinking of adjusting the preload of those 30mm drooped main springs by making the helpers only Just closed
To me it's still full pressure on the light side tyre by the main spring at full SB twist
At 70mm droop with all rear & front tyres off the ground, the helpers will still keep the main & helper in tact

Dallas J

iTrader: (1)

Are you shocks dual height adjustable? If not, then you dont have a lot of choice, just set perch height for ride height.

If you do have body length adjustment as well, I would be looking at bump stop clearance first. Need to make sure your travel isn't going to limit you and riding on the bump stop. Next would be making sure you have enough droop from your static ride height. I like about 2" in both directions.

If you run enough spring rate (I dont think your 672 is enough, would up that to 900-1000 to start) then you'll have the rear unseat before you reach full droop. Itll pretty much unseat around 1" of droop at the wheel and then you'll have to deal with that 1" of slack. Id just run a low rate (4kg/mm or so) assist spring with high preload.

Front you shouldnt need any assist/tender or helper. Up front its just extra weight to carry. According to some, technically the rear tender is just extra weight to carry but I find it helps a ton through bumps in just the ride feel and smoothness of the ride.

GTA.RS

Thanks Dallas.
A bit more detail on my GTA here.
RS 12 clutch rear diff
Front wavetrac with my mapped ACD
Front Kings 65idx200 11.6kg/650lb. Didn't put the tender springs up front as you said.
Rear Racing Logic 63idx180 12kg/672lb. Tenders 72idx100 1/4"dia coils. Very strong.
Whiteline sb 27 on the softest setting. Overkill I know. Front std sb.
To close the tenders on top of the mains it took 65mm downwards to close
the tenders to 50mm & the mains compressed to 165mm. -15
Fronts preloaded 6mm
Rear I set the mains at that 165mm on the ground.
Rear droops 60mm
Cons: Tein Zs at -3 from max each end to make the rebound steady.
Result keen on the street so far, Predicable & neutral.
Feedback to the steering wheel feels a dat harder but very accurate.
That's because of the front duroball +caster. I do like it self straightening.
Whiteline antidive front ball joints. Control arms level.
Heights on 18x40x245 are F665mm R660mm
If it was a dedicated track car, I'd go harder springs & alignments.
It's corner weighted but a compromise for street.
Auto box built by me. All 4 planetry geared x3 with very high pressures etc.
Any feedback on this setup appreciated Dallas.