Rear ride height adjustment issue

[Hobby Racer]

Anyone else have an issue getting the rear ride height high enough using the 'R' shock location? On the drivers side rear, I can only get 3.375" height measured to the underside of the frame rail, and that is with some preload applied to the spring. The passenger rear does not seem to have the same issue, plenty of adjustment.

Thinking I may need to switch the the 'S' shock location in the rear so I can get at least 3.5" clearance, plus the springs will settle a bit with use and I want to be able to raise it up to compensate.

[Mitch Wright]

I am running 3 5/8 plus or minus a little with drivers weight and I do have some preload on the left rear.

[DanielsDM]

I'm using the lower hole for the upper rear shock mount and have the rear ride height currently set at 3 1/4. The shock has around 1 inch of stroke before it contacts the bump stop. My car hasn't turned a wheel yet so everything is subject to change.

[RetroRacing]

I think 1" of stroke will bottom out, even with a heavier spring rate (we use 700lb in the rear and see more than an inch of movement) which will make for a very loopy experience! I will check our ride height out when I get the car back from the engine builder.

[Hobby Racer]

I think 1" of stroke will bottom out, even with a heavier spring rate (we use 700lb in the rear and see more than an inch of movement) which will make for a very loopy experience! I will check our ride height out when I get the car back from the engine builder.

I am also using 700lb rear springs, I'll be very interested in your rear ride height and if you needed any pre-load on the right rear shock to achieve your height.

[Mitch Wright]

Personally I didn't like the stiff set up that I tried, I thought the car felt skatey. I went as high as 450/650 (on BFG R1 S tires) and now back to 350/550 or 500 with a front sway bar. At least at NCM the car is quicker and I feel much more comfortable, which is always worth some time.

[Hobby Racer]

What is the surface like at NCM? I mostly run at Watkins Glen and it just got repaved so it is super smooth. The stiff setup should not be a problem there, I hope.

I like a softer setup myself, but with the high down force and braking potential, I'm thinking the nose would get a lot of scraping.

[Wayne Presley]

Mitch, the 818R that I did for FFR used the Hoosier A7 and compared to the Rivals they are way stickier. It's not surprising that you like the softer springs with the Rivals. When I was racing motorcycles, I'd have to up spring rates to run slicks over DOT tires.

[Hobby Racer]

Mitch, the 818R that I did for FFR used the Hoosier A7 and compared to the Rivals they are way stickier.

I think Mitch is running the BFG equivalent of a Hoosier A7, not the Rival street tires. Correct me if I'm wrong Mitch.

I have run the BFG R1's in the past and they are on par with the Hoosiers.

https://www.tirerack.com/tires/tires...l=g-Force+R1+S

[Mitch Wright]

Correct the R1 S comes up to temp quicker than the R1 and is the equivalent to the A7. The BFG's don't fall off with heat cycles like the Hoosier A7 and I have found them to be as quick if not quicker than the Hoosier. I have actually gone smaller with this round of tires, 215/40X17 and 245/40X18 from 235/40X17 and 265/35X18. Actually ran 1.6 second quicker than I had run late last season with the smaller set up.
We had NASA Great Lakes here this weekend unfortunately I had to work but the go0d news my car is on par with the ST2 winning Lotus(really trick car) and 2nd place Corvette.

[RetroRacing]

We run the stiff rear set up because of the tunnel, diffuser and wing (lots of downforce).

[Wayne Presley]

Mitch, The FFR car has the race splitter out 4.5" from the front, dive planes, flat bottom car, diffuser and the 67" wide GT250 APR wing. What aero are you running?

[Mitch Wright]

Hi Wayne,
I am at 4.5 on the splitter, Dive planes, Flat Bottom, rear diffuser, the APR GTC300 that FFR was selling that I believe is 67"(Yes after the fact I would have gone with the GT250) This last time out I have lowered the rear 1/8 and running 2* angle of attack in the center on the wing.
What I have yet to do is cover the lower front radiator opening which is said to help the front downforce. I have yet to have the car understeer high or low speed.
3.25 front ride height 3.5 rear
Now that I feel the car is getting to a good baseline and will play around more with angle of attack, I found early on that the straight line difference between 5* and 2* was 5 mph on our straights. I would like to see if I can get to high speed aero push playing with angle of attack, wickers.
Just more fun.

Wayne it would be fun if it ever worked out to get the FFR car here to compare data, your car has 100hp or more but would still be interesting. Or I have been thinking about a trip to either Barber or Atlanta.

[Hobby Racer]

Mitch, The FFR car has the race splitter out 4.5" from the front, dive planes, flat bottom car, diffuser and the 67" wide GT250 APR wing. What aero are you running?

Thought you were running the GT-1000 dual element wing on FFR's car?

[DanielsDM]

I think 1" of stroke will bottom out, even with a heavier spring rate (we use 700lb in the rear and see more than an inch of movement) which will make for a very loopy experience!...

You may be right. I haven't run it yet so I don't know, just pointing out where the ride height is and how much stroke is available. I may use the upper shock mount holes but the driver side shock rubs in that location, some grinding will be necessary.

[Mitch Wright]

I did have to clearance both shocks top bearing housings about .005.

[Wayne Presley]

Hi Wayne,

Wayne it would be fun if it ever worked out to get the FFR car here to compare data, your car has 100hp or more but would still be interesting. Or I have been thinking about a trip to either Barber or Atlanta.

That would be fun, the FFR car is in Mass though...

Thought you were running the GT-1000 dual element wing on FFR's car?

No, APR GT250 at 67" wide

[RetroRacing]

We run 0 on the 250 wing on the 71" with gurney flap, 48" diffuser on a tunnel car, so hard to compare.

[Mitch Wright]

Well Wayne I am sure it could us a little more of your TLC??

[Wayne Presley]

It does need some more, I think there is another 3 seconds in it at VIR... Now to convince the powers at be to do so. I'd love to make that car into a coupe track car...

[Mitch Wright]

2-3 second improvement would be impressive and I am sure not out of reach based on the tweaking and time improvements I have experienced.

I like the idea of a coupe, that very thought had crossed my mind. I would think the straight line speed would improve some for sure. My wife keeps reminding me that between keeping the 818 track ready and my Ecoboost Falcon project its not a good idea to add to my list.