Plastic Fantastic 2

Interesting, stuff there. I thought one guy said they were swapping a arms and everything from c6’s, but I think the thread got deleted. :). Too much arguing.

Another thing you might think about is trying the transverse spring from a c5z. I really liked the c5z handling as it was. Maybe your coil overs are hurting you.
 
rtj said:
Interesting, stuff there. I thought one guy said they were swapping a arms and everything from c6’s, but I think the thread got deleted. :). Too much arguing.

Another thing you might think about is trying the transverse spring from a c5z. I really liked the c5z handling as it was. Maybe your coil overs are hurting you.
Click to expand...

I have many questions now (after seeing those numbers). Functionally I weight the same as a C5/C6 - but I have square springs (same all around)... I even have the same weight distribution - so maybe my coil springs are causing me grief by not allow the weight to shift when I let off the throttle.... I think for my track day on Wednesday, I'll leave them be, but once I'm done - I'll change a pair of springs..... not sure it'd be a good idea to go softer in the front.... the other thing I could try is soften the compression on the front springs... it'd tell me the same thing.

so many questions.....

calculated the percent..... 43/57 - pretty much for all those 3 suspension configurations.... and I think I will try the 400s back on the front then increase the compression damping.... I may end up changing all of them, but at least that will give me an idea if it's moving in the right direction (other reason I won't swap springs is my friend's C3 is on my lift)
 
Last edited:
time to resolve a cooling issue... the cap needs to be the highest point
4n2DbHsh.jpg
the fix
lg5hbOch.jpg
slcMCZvh.jpg
with a new top 'hose'
hyEY3QBh.jpg

oh the good old days...edited
​​​​​​​OtA0xcrh.jpg
 
BBShark said:
..............................
I've never seen this but, don't tires have an optimal unit area load? So making the contact "patch" area bigger (with a wider tire) could actually decrease traction (with a smaller unit area load)?
Click to expand...


AFAIK, no. Each tire's tread design/compound obviously has a different "base" coefficient of friction/grip. But, once you normalize the "base" C of F from different tires, and then change/increase the loading, you get a load/grip curve that shows the tire getting an ever-decreasing percentage of grip increase with each percentage increase in load (eg: 10% increase in load gets a 9% increase in traction/grip, add another 10% loading and get an 8% increase in traction/grip, ....). This bites us in the ass when it comes to cornering ability, as the incremental centrifugal force increase from the mass always overpowers the additional incremental grip due to the weight/mass.

That's why loading the tires with higher vehicle mass results in poorer cornering, but loading the tires with "zero mass" aero downforce improves cornering.
 
69427 said:
BBShark said:
..............................
I've never seen this but, don't tires have an optimal unit area load? So making the contact "patch" area bigger (with a wider tire) could actually decrease traction (with a smaller unit area load)?
Click to expand...


AFAIK, no. Each tire's tread design/compound obviously has a different "base" coefficient of friction/grip. But, once you normalize the "base" C of F from different tires, and then change/increase the loading, you get a load/grip curve that shows the tire getting an ever-decreasing percentage of grip increase with each percentage increase in load (eg: 10% increase in load gets a 9% increase in traction/grip, add another 10% loading and get an 8% increase in traction/grip, ....). This bites us in the ass when it comes to cornering ability, as the incremental centrifugal force increase from the mass always overpowers the additional incremental grip due to the weight/mass.

That's why loading the tires with higher vehicle mass results in poorer cornering, but loading the tires with "zero mass" aero downforce improves cornering.
Click to expand...

where does heat come into this equation? friction from rotation and drag would help heat a tire, but is there a point where there isn't enough mass to create enough heat to optimize grip? There is a huge fight whenever someone brings up flotation v. skinny tires on a 4x4. while it is true that flotation will get you across an increasingly liquid surface, there comes a point where traction is lost *usually on a side hill* by analogy, it seems there would be a similar point here. That once the tire is so wide that it no longer gets hot enough to increase traction - that a smaller contact patch would, actually, have better grip....

or am I thinking of this wrong?
 
So. Track night in America.

f**k Washington, its traffic and the idiots who think choo choo trains solve anything.

Nothing is so annoying as reserving 3 hours to drive 1 1/2 hours then realizing at hour 3 that you're not half way there.

HOWEVER.

I got home, unloaded my car and saw a huge oil slick where the trans continues to leak. Probably would have blown it up at the track - so I guess I dodged a bullet, but still annoyed that I missed yet another opportunity to race.
 
I’ll throw this out there, pretty much speculation, but...

Those front c5 a-arms look pretty thin and if your coil-overs mount similar to the original shocks, you may be deforming their shape when highly loaded.

The transverse spring (oem) looks like it pulls vertically, so puts minimal axial load on the a-arm. To get the same vertical load as oem, the axial (tensile ) load will be a significant percentage of the vertical when using coil overs.

The design was for vertical loading from the spring. A bit of an oddity.

Since it is aluminum, if it yields (permanent deflection) then your static/resting geometry would be messed up too (not just at speed in a tight corner). Thin alum parts are more susceptible to yield.

Sorry to be so negative, but you were looking for reasons. But, there are lots of what-ifs involved.
 
Last edited:
rtj said:
I’ll throw this out there, pretty much speculation, but...

Those front c5 a-arms look pretty thin and if your coil-overs mount similar to the original shocks, you may be deforming their shape when highly loaded.

The transverse spring (oem) looks like it pulls vertically, so puts minimal axial load on the a-arm. To get the same vertical load as oem, the axial (tensile ) load will be a significant percentage of the vertical when using coil overs.

The design was for vertical loading from the spring. A bit of an oddity.

Since it is aluminum, if it yields (permanent deflection) then your static/resting geometry would be messed up too (not just at speed in a tight corner). Thin alum parts are more susceptible to yield.

Sorry to be so negative, but you were looking for reasons. But, there are lots of what-ifs involved.
Click to expand...

valid thought and easy enough to check.
 
SuperBuickGuy said:
rtj said:
I’ll throw this out there, pretty much speculation, but...

Those front c5 a-arms look pretty thin and if your coil-overs mount similar to the original shocks, you may be deforming their shape when highly loaded.

The transverse spring (oem) looks like it pulls vertically, so puts minimal axial load on the a-arm. To get the same vertical load as oem, the axial (tensile ) load will be a significant percentage of the vertical when using coil overs.

The design was for vertical loading from the spring. A bit of an oddity.

Since it is aluminum, if it yields (permanent deflection) then your static/resting geometry would be messed up too (not just at speed in a tight corner). Thin alum parts are more susceptible to yield.

Sorry to be so negative, but you were looking for reasons. But, there are lots of what-ifs involved.
Click to expand...

valid thought and easy enough to check.
Click to expand...

an article which helps
https://www.lsxmag.com/tech-stories...-corvette-suspension-tech-coilovers-vs-leafs/

The upper shock mount (which is potentially a problem with the C5/C6) isn't an issue because I knew I was going coil-over and built it stout enough to handle the load.

As far as the lower arm - that article talks about how the stock spring transfers load from one side of the car to the other.... it isn't deformed... but I'll certainly watch it closer.

In other news, took a friend for a ride yesterday - and it got a bit warm.... so now to trace that issue. If not one thing, it's something else. I still feel like I'm narrowing down the build issues and now can start focusing on making it faster.
 
Last edited:
Pleased to see the "Leaf-it-Alone" comment. That is my front IRS - but keeping coil-over in reserve! Like the idea of spring and ARB in one - but it is non-adjustable (from the cockpit). GRIP, GRIP, GRIP!

And, they say:
When you’re looking to shave every tenth of a second off your lap times, then its time to step up a set of adjustable coilovers.
Click to expand...

SO, TBD. I'll stay tuned; so-to-speak...

Cheers - Jim
 
In wheel searching... I came across this at https://support.apexraceparts.com/h...idebody-Corvette-Wheel-Tire-Fitment-Guide#htr

Wheels

Front: 18x11" ET38 // Rear: 19x12.5” ET55
Available in: SM-10
Popular Fitment
Tires

APEX Staff Pick: Front 315/30-18 // Rear 325/30-19
A minimum of -2º front and -1.5º rear camber suggested
Extreme Performance Summer: Continental Extremecontact Force (200 TW)
R-Compound: Nitto NT01 (100TW), Toyo R888R (100TW), Nankang AR-1 (100TW)
Semi-Slick: Hoosier A7 (40TW), Hoosier R7 (40TW)
Wider Alternative: Front 315/30-18 // Rear 345/30-19
A minimum of -2º front and -1.5º rear camber suggested
Extreme Performance Summer: Continental Extremecontact Force (200 TW)
R-Compound: No options currently available
Semi-Slick: Hoosier A7 (40TW), Hoosier R7 (40TW)
Narrower Alternative: Front 295/30-18 // Rear 325/30-19
A minimum of -2º front and -1.5º rear camber suggested
Extreme Performance Summer: Continental Extremecontact Force (200 TW)
R-Compound: Pirelli Trofeo R (60 TW), Nankang AR-1 (100 TW)
Semi-Slick: Hoosier A7 (40TW), Hoosier R7 (40TW)

not sure I can stuff a 315 under the front but maybe a 295?

Another thing, I need to find some C7 flares.... maybe that would be the best way to get the tire/wheel I want under the car....
Currently, I think I'm -1.5 degrees front and maybe -1.0 rear.... now I've got to check
 
shop full of C3s
7dgtHwN.jpg
time to fix an exhaust leak
33jBVV4.jpg
guaranteed.... just like the last one
ePlz1mL.jpg

also did some fixes on the cooling system.
about the transedited
it was overfull
qdQKstr.jpg

which could be the leak... I'll know tomorrow...edited

PS C3
it's getting a rear suspension... the old one was VERY worn out... so it's getting a full upgrade
WQIuj5G.jpg
VY7uB9W.jpg

​​​​​​​then a motor.... then a front coil-over...edited
 
SuperBuickGuy said:
In wheel searching... I came across this at https://support.apexraceparts.com/h...idebody-Corvette-Wheel-Tire-Fitment-Guide#htr

Wheels

Front: 18x11" ET38 // Rear: 19x12.5” ET55
Available in: SM-10
Popular Fitment
Tires

APEX Staff Pick: Front 315/30-18 // Rear 325/30-19
A minimum of -2º front and -1.5º rear camber suggested
Extreme Performance Summer: Continental Extremecontact Force (200 TW)
R-Compound: Nitto NT01 (100TW), Toyo R888R (100TW), Nankang AR-1 (100TW)
Semi-Slick: Hoosier A7 (40TW), Hoosier R7 (40TW)
Wider Alternative: Front 315/30-18 // Rear 345/30-19
A minimum of -2º front and -1.5º rear camber suggested
Extreme Performance Summer: Continental Extremecontact Force (200 TW)
R-Compound: No options currently available
Semi-Slick: Hoosier A7 (40TW), Hoosier R7 (40TW)
Narrower Alternative: Front 295/30-18 // Rear 325/30-19
A minimum of -2º front and -1.5º rear camber suggested
Extreme Performance Summer: Continental Extremecontact Force (200 TW)
R-Compound: Pirelli Trofeo R (60 TW), Nankang AR-1 (100 TW)
Semi-Slick: Hoosier A7 (40TW), Hoosier R7 (40TW)

not sure I can stuff a 315 under the front but maybe a 295?

Another thing, I need to find some C7 flares.... maybe that would be the best way to get the tire/wheel I want under the car....
Currently, I think I'm -1.5 degrees front and maybe -1.0 rear.... now I've got to check
Click to expand...


Okay quote and what is right now.
-1.1 F camber
-.9 rear

.30* TO (or 1/8" TO)

I was asked to measure steering angle.

all at 25*
3/4" TO
3.6 degrees (I think)
-1.75 camber inside
-1.375 camber outside

I sound 'smart' but the terms come from this article
https://ismasupers.com/downloads/tech-talk/tech-04understandingsteering-4.pdf

pretty pictures
C7P1lN3h.jpg
H2KDm4M.jpg
 
Last edited:
and add rear steering... ATM, it's neutral but I could actually change how the rear steers the car...

so much to learn. feels like I'm standing on the earth at its furthest point from the moon, and am walking all the way to the moon... I'm not even above sea level yet....
 
TKX .... yay or nay?

it's a lot of money - but the biggest hesitancy is 600 lb torque limit. It would be annoying to buy it then have it put man glitter across the road course....
 
Other Corvette's control arms
doI25pgh.jpg
and new battery for PF2
GRqfLQSh.jpg

in other news, I'm at the maximum camber for the rear so it's not going to be easy to get another -.5 degrees
 
You must log in or register to reply here.

Latest posts

Back
Top