Plastic Fantastic 2

[SuperBuickGuy]

if you make the bushing non absorbing isnt it going to twist the tube again? those tires are creating lots of grip

same might be said for using poly.... in this case, I'm firmly in the "I dunno" camp - but it is one of those things I'll be looking at as I do this. There really isn't that much 3d rotation on the arm... it's fixed to the frame and the knuckle does rotate a bit throughout the suspension travel.... which is a solid 2" (in both directions)....

but I hear you - I wonder if I get rid of the hop then find the weakest metal in the frame when it gets torn out.... they don't call it the bleeding edge for nothing :banghead:

 

[SuperBuickGuy]

and it's tomorrow... and there's CAD

now in metal

then some loving with a grinder

some fitting

then welding

now welded


tomorrow a bit of grinding and some paint
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[bobs77vet]

i......- I wonder if I get rid of the hop then find the weakest metal in the frame when it gets torn out.... they don't call it the bleeding edge for nothing :banghead:

I recall one guy had cut gussets out of thick steel for every corner of his C3 frame and reinforced everything. for sure you are pushing the limits on horse power, and beefy tires .....maybe if things keep breaking you go to less traction on the tires and do more burn outs instead.

 

[SuperBuickGuy]

i......- I wonder if I get rid of the hop then find the weakest metal in the frame when it gets torn out.... they don't call it the bleeding edge for nothing :banghead:

I recall one guy had cut gussets out of thick steel for every corner of his C3 frame and reinforced everything. for sure you are pushing the limits on horse power, and beefy tires .....maybe if things keep breaking you go to less traction on the tires and do more burn outs instead.

I'm hoping that adding lightness is going to help in this arena.. to remind, I'm 600 lbs less then shipping weight

 

[mfain]

i......- I wonder if I get rid of the hop then find the weakest metal in the frame when it gets torn out.... they don't call it the bleeding edge for nothing :banghead:

I recall one guy had cut gussets out of thick steel for every corner of his C3 frame and reinforced everything. for sure you are pushing the limits on horse power, and beefy tires .....maybe if things keep breaking you go to less traction on the tires and do more burn outs instead.

I'm hoping that adding lightness is going to help in this arena.. to remind, I'm 600 lbs less then shipping weight

Have you looked a fabricating adjustable toe links using round tubing and heims? Several companies offer them for the Camaro suspension. Here is an old post from Apex Motorsports:

"Toe links are one of the critical components in reducing/eliminating wheel hop and improving traction. The wheel hop "trifecta" is sub frame bushing, trailing arms, and toe rods. Each contributes to limiting/eliminating some portion of the the movement and deflection that causes wheel hop. Toe rods fight the deflection that causes toe changes in the rear wheels under hard acceleration. This deflection reduces the contact patch of the rear tires thus reduces traction."

Pappy

 

[SuperBuickGuy]

i......- I wonder if I get rid of the hop then find the weakest metal in the frame when it gets torn out.... they don't call it the bleeding edge for nothing :banghead:

I recall one guy had cut gussets out of thick steel for every corner of his C3 frame and reinforced everything. for sure you are pushing the limits on horse power, and beefy tires .....maybe if things keep breaking you go to less traction on the tires and do more burn outs instead.

I'm hoping that adding lightness is going to help in this arena.. to remind, I'm 600 lbs less then shipping weight

Have you looked a fabricating adjustable toe links using round tubing and heims? Several companies offer them for the Camaro suspension. Here is an old post from Apex Motorsports:

"Toe links are one of the critical components in reducing/eliminating wheel hop and improving traction. The wheel hop "trifecta" is sub frame bushing, trailing arms, and toe rods. Each contributes to limiting/eliminating some portion of the the movement and deflection that causes wheel hop. Toe rods fight the deflection that causes toe changes in the rear wheels under hard acceleration. This deflection reduces the contact patch of the rear tires thus reduces traction."

Pappy

Those are the $396 option I mentioned before... the toe is adjustable already - it's the same cam system as the Corvettes... and I know, they're hated by people who can't tighten a nut not to be mean or anything :lol:


There is, also, kind of another reason I'm not doing the tubular options. The rules say "stock attachment points and stock arms"... pushing the envelope here could be a problem.... I didn't look close enough at the GTV class cars at SEMA 2019 to know how enforced that rule is....

 

[mfain]

Since you have a Camaro rear suspension in a Corvette, what is considered a "stock attachment point or stock arm"? I can pretty much assure you that none of the GTV Corvettes are running the stock rear lower links - they have all been replaced with tubular rods and heims. You have entered the land of big horsepower and big tires, so you may find stock eccentric adjusters just won't hack it, no matter how hard you crank on the bolt. I would also be concerned that a "flat" toe rod may not have enough rigidity in all directions to keep from flexing under the load you will be applying. I think an .095 wall 1.25" tube would be much stiffer. With some tubing, weld-in tube ends, heims, and your fabrication skills you could whip up a set a whole lot cheaper than $396. Here is one I built for the Detroit Speed Deca-link that had to have a specific metric joint on one end to bolt to the Decalink upright and a 3/4" heim on the other.

 

[SuperBuickGuy]

good news, the arms installed just fine

nothing to see here, just stock arms
those bushings? yep, just rubber or something

bad words

turns out 3 of 4 rims are bent, one so badly that I doubt it can be fixed.... good news is is the seller is sort of standing behind his sale....edited

still not sure on the grey.... maybe? I'm either going with what was on it or something new.... that said, ordering wheels right now is not a fast process

I don't like them because they're the same as everyone else's

​​​​​​​

 

[SuperBuickGuy]

Since you have a Camaro rear suspension in a Corvette, what is considered a "stock attachment point or stock arm"? I can pretty much assure you that none of the GTV Corvettes are running the stock rear lower links - they have all been replaced with tubular rods and heims. You have entered the land of big horsepower and big tires, so you may find stock eccentric adjusters just won't hack it, no matter how hard you crank on the bolt. I would also be concerned that a "flat" toe rod may not have enough rigidity in all directions to keep from flexing under the load you will be applying. I think an .095 wall 1.25" tube would be much stiffer. With some tubing, weld-in tube ends, heims, and your fabrication skills you could whip up a set a whole lot cheaper than $396. Here is one I built for the Detroit Speed Deca-link that had to have a specific metric joint on one end to bolt to the Decalink upright and a 3/4" heim on the other.

View attachment 2467

the rule and loophole that works for this year is this.... they say it must be stock attachment points then goes on to say that you can change within the product line.... they don't limit what year - while the body/frame must be 1989 and older, they don't specifically state that the suspension points cannot be from much newer lines (the loophole)...

Which brings up a question - will they change the rules because of a clever novice? I suspect 2022 will bring a rule that says that the attachment points must also come from pre-1990.... otherwise, I'm sure one wiff of this hits the track and we see rebodied C7s in 2022. Already there are at least 2 other Corvettes copying my suspension concept that are in production.... (and in that vein, I thought there wasn't enough room for the C5/6/7 transaxle behind rear firewall.... there actually is).

But I don't know - my experience with sanctioning bodies comes from my bicycle racing days where they had no conscience about changing rules mid-year to quash the clever riders.

the point of all of that is how perfect do I want to make this? I'm already the 3 year old with Thor's hammer - I could spend a lot of money but I'm still a wet-behind-the-ears autocrosser who may not be able to even stay on the track....

That said, you do have me thinking about that idea of control arm...

 

[SuperBuickGuy]

In looking for other wheels, the Grand Sport wheel has, apparently, because the 'new thing'.... that's me, curve maker.... I can take anything simple and make it curved....:thankyou:

 

[mfain]

In looking for other wheels, the Grand Sport wheel has, apparently, because the 'new thing'.... that's me, curve maker.... I can take anything simple and make it curved....:thankyou:

The C7 Z06/GS wheels are known to bend with track use, especially with big tires - so much so that there was talk of a class action law suit. Lots of info on "the other forum" about which wheels are strong enough to take the abuse you about to dish out.

 

[SuperBuickGuy]

In looking for other wheels, the Grand Sport wheel has, apparently, because the 'new thing'.... that's me, curve maker.... I can take anything simple and make it curved....:thankyou:

The C7 Z06/GS wheels are known to bend with track use, especially with big tires - so much so that there was talk of a class action law suit. Lots of info on "the other forum" about which wheels are strong enough to take the abuse you about to dish out.

what do you like?

 

[mfain]

In looking for other wheels, the Grand Sport wheel has, apparently, because the 'new thing'.... that's me, curve maker.... I can take anything simple and make it curved....:thankyou:

The C7 Z06/GS wheels are known to bend with track use, especially with big tires - so much so that there was talk of a class action law suit. Lots of info on "the other forum" about which wheels are strong enough to take the abuse you about to dish out.

what do you like?

I have Forgeline GA-3Rs and Finspeed F14s for my track cars. Some of the late model Corvette guys like the Forgestars and a few have recently switched to Apex wheels for the track.

Forgeline


Finspeed

 

[SuperBuickGuy]

fixing another soft point

short welds, plus a weakened point so it collapses there in an accident

so a decision point.... they have a poly bushing for this mount.... the mount is thin rubber around a steel sleeve.edited The kit doesn't change the upper and lower arms - just this one.... which means that if there is stress, this is the one that would take the most stress.... so I'm not changing it - it's a pain to change, but I think having one pivot that cannot twist but 2 others which can is a bad idea...

even got my bushing remover out before I decided no

back to the arm.... first clean the joint

then straighten the collapse joints then weld the seam completely


this clearly isn't the strongest it could be - however, removing the collapse point, putting a poly bushing on the inside pivot, then welding the length should make this greatly improved....edited
​​​​​​​

 

[SuperBuickGuy]

In looking for other wheels, the Grand Sport wheel has, apparently, because the 'new thing'.... that's me, curve maker.... I can take anything simple and make it curved....:thankyou:

The C7 Z06/GS wheels are known to bend with track use, especially with big tires - so much so that there was talk of a class action law suit. Lots of info on "the other forum" about which wheels are strong enough to take the abuse you about to dish out.

what do you like?

I have Forgeline GA-3Rs and Finspeed F14s for my track cars. Some of the late model Corvette guys like the Forgestars and a few have recently switched to Apex wheels for the track.

Forgeline
View attachment 2468

Finspeed
View attachment 2469

thank you for the suggestions, I only knew of Forgeline.
I think my problem is I have custom tastes on a off-the-shelf budget.... that said, there are some potentials there - the biggest issue with off the shelf is I need a front wheel drive offset for the front and a concave for the rear.... front, stock is -44 and should be -50 or even -55 on a 10 inch wheel, rear is -57 on a 12 inch wheel but could be up to a -44...

 

[mfain]

Your issue with offsets is why I went to the Forgeline GA3R. It is a three piece wheel and they can build it in any offset you need. With the Finspeeds, a one-piece forged wheel, I had to purchase a special Corvette Daytona prototype forging for the rear that they could machine to a shallow 5.75 inch backspacing. The regular forgings could only be machined to about a 7 inch backspacing - or deeper. BTW, if you monitor the classifieds in the road racing and autocross section of the Corvette Forum, there are often some pretty good deals on used track wheels.

 

[SuperBuickGuy]

in all my looking about, if I can find 18x10 rears from an earlier c5 - I can use those on the front because the offset is much better... or just raise the ride high a bit... we will see, at this level, it's rubbing on the front.
In other news, the rear isn't moving around like it did
ready for an evening cruise


that ends on a tow truck...
glad I put panels in place....edited

all of this because a ground fell off



​​​​​​​ah well, glad it's happening now...edited

 

[bobs77vet]

you can find cheap C5 wagon wheels if you need to mock something up.


tow trucks rides are a part of the true american hot rod experience!

 

[SuperBuickGuy]

there has been another ride....

5600 rpm, valve floats enough to move off the pushrod... how to fix? to remind, solid roller cam, .16 lash
450# at 1" valve spring....

that said, even when warm it seems noisy...

 

[SuperBuickGuy]

I talked this through with the guy who did the machine work last night.... the tl;dr answer is I probably need a stud girdle.... which may be interesting with the chinese heads.... to be continued....

and

I bought too short exhaust pushrods (though, so far, it's only been intake that's been coming apart).editededited
Also, I should have bought .135 wall thickness pushrods, not .080... 7/16 won't fit... so that's not an option (now - though next motor, that will be an option).


and
this is my first, fast, BBC.... mistakes will happen and I'm okay with it (would rather it didn't happen, but it does and it will.... and I still think it will be faster then any LS)...