My first race (in a car)...in the rain...stock motor ITR...Hoosier Dirt Stockers...rarely get so close to heaven...want to get back so bad:

 

Get back out there

 

who was in your class?
the Porsche's or the rabbit?

 

Well you could just look at the "class" column...

 

I homer'd it

 

Come on Scott.... you can do it!

 

Ah... "can do it"... I'm actually "doing it now"... and by doing it I mean RE-doing parts I've already made because I had made compromises that nagged at me.

The mechanical aspects of the rear brakes and rear suspension are Done as of yesterday (Re-done - found the lowest height rotor that would work - Mazda6 at approx .200 less than the Maxima to buy some extra clearance for my sway bar at full bump - and had to make a new set of radial caliper mounts the hard way), and now I'm working on the front, and that's gonna take a little time.

After seeing Greg Amy's suspension cam footage I'm replacing the factory LCA's (that WERE Done using Chris Brinson's Kingpin rear bearing and my own front spherical) and making up new fabbed ones (which will be just a little more challenging than RTR and Andre's TSX examples because of the multiple ideas I want to apply). The sway bar pickup is the biggest PITA, pain I not that long ago would have dismissed and foregone but now consider essential and mandatory.

Currently working on the front UCA's - a blending of Stock Car and Formula Car attributes for what I'm sure will be the most unneccessarily trick arms EVAR.

Then with that done (sometime before Christmas), I'll have a rolling tub and decisions to make about everything else.

Scott, who found the problem getting the car done...it's Me!

 

Sounds like someone needs to buy a turn-key racecar to race while the racecar is being tinkered with.

 

Yeah, way more movement on Greg's video than I'd have expected. You thinking that it's all in the LCA?

 

This I'm in for. I've got a couple of random sketches and notes on this and I've been stewing on them for longer than I care to admit.

As for your second statement... I feel you. I keep making myself other projects while my coupe sits in the corner slowly becoming a tomb for its own parts. I badly need to start making headway.

 

Id have to agree.
Scott get anotha Kaaa so you can continue to tinker and have fun and the memories will be more fresh than the ones that only come back to you when you see the paper.

 

I watched and watched that video. I think it's either the LCA's or the subframe. I really don't think it's the rear LCA pivot on that car since it's spherical and the factory carrier should be sufficient to the lateral load. And I have a hard time believing that the subframe, with as much section as it has, could be the culprit. But then again the factory went to the trouble to provide a tubular brace (albeit some distance from the load and made of bent tubing). And certain aftermarket companies have sold braces to connect the LCA front pivot bolts (though those braces that I've seen have been made of bent tubing to clear the exhaust and so both flex and hang down vulnerably low).

Only possible solution? Eliminate the potential sources of flex! Why? Because a giant variable like this cannot be helpful in evaluating whether/how much masking the tire aligning torque Mz with Fy and caster is helpful to me. Well behaved parts contribute to a well behaved car.

Scott, who doesn't need Another car...to put it mildly...renting indoor karts for $20 a nite FTW...

 

20 bux a night??? for reals? I need to buy a plane ticket.

 

I hear ya... I guess in my head, I'm not convinced that what I'm seeing is:

1- that consequential- these are tin top production cars. There's likely a ton more movement/flex in other parts of the chassis that we can't and don't address.
2- fixable- it may be a function of the very small amounts of play in the sphericals combined with small amount of mount flex. Add these together and then place the measurement/viewing point way out at the end of the "lever" and that's just what you end up with. If this is the case, a stiffer LCA won't do anything to change the situation.
3- even "real"... given the fisheye GoPro, plastic mount, shadows, lighting, suspension compression under braking, etc it may be an optical illusion or it may be visually amplifying the amount of movement.

This isn't to say that you shouldn't go down the rabbit hole here just that I probably wouldn't.

 

Stared and stared...till doubt grew like a pearl in my mind...such pearls as My mind produces anyway...

Say "you wouldn't"...Do "you wouldn't"...so hard to know if there even is any fruit hanging that high...

Stared and stared...thought and thought..."Aw Dammit!"

Scott, who is now several rabbit holes in anyway...

 

I thought about gregs video a couple days ago... I was jumping the curbs in 4-5 at VIR and up the esses. I thought "man, if greg's late 90's teg flexes, what's happening to my 89 crx!"

then I stopped caring because driving this, and all, racecars is so much fun, and if it falls apart at speed that's why it has a good rollcage and a new harness. I'll nut-and-bolt it, and check the brakes, and flog it until it cracks in half

 

Could anyone link this lurker to this video that has caused so much concern?

 

Maybe this?

 

yikes WOW

 

One of the differences between us is that I stare at the parts... and I think. And then a light bulb pops on. Some head scratching... and I decide that the juice isn't worth the squeeze.

Just this past weekend I was talking with someone about my great new idea that involves a from scratch UCA with a relocated upper ball joint in conjunction with the stock upright... I'm fine having someone else blaze the path while I continue playing with the stock parts.

It's not about falling apart (to me) but it IS about diminishing the value of all the other tuning, tweaking, and parts that go into the car and setup. What's the point of custom bars and triple adjustable shocks if you can't even get the wheel/tire not to wander around under load?

 

Yeah, it does seem hard to justify a lot of work removing the "flex" from the lower control arm when the tire is moving around that much...

Seriously though, that looks to me like compliance in the rear bushing...are you sure he had spherical bearings installed in that location when this video was made? If the lower control arms are really flexing that much I would think fatigue failure would be a common problem on track integras. The forces on the arms should be fairly easy to ballpark based on car weight and braking g force. You could pretty easily build a jig to apply a load and measure deflection of the arm at a force close to this, and determine if the video is actually showing a real issue.

 

I'm absolutely, 100000% positive the suspension in the video above had full sphericals.

 

yup, full fancy spherical

I'm tempted to video my almost-all-poly-some spherical stuff on my crx now. Just for curiosity

 

Make sure to run two cameras... That way you'll be able to cut from camera 1 to camera 2 when the wheel moves out of the field of view.