Part of me feels like there needs to be more metal outboard of the V on the lower control arms. They are probably fine but it just looks like it should be more. I am also probably underestimating their diameter as I assume they are 1"OD which is probably incorrect.
Everything looks great as always and it's so awesome to see how fast this one is coming along.
In reply to nocones :
They did come out looking a little different than "normal" but they should be plenty strong.
A big part of that was ease of fabrication (no bends) and just were things fell into place for the chassis side mounts. I could have definitely made a more conventional design with some bends on the tubes.
However a big part of where my thinking was on this is the goal of light weight. I overbuilt the arms on the other car...A LOT! And when I look at circle track stuff their lowers are just two 1" od .120 wall swedge tubes with rod ends... nothing all that special considering those cars are meant to survive wheel banging. Several of those designs have the "V" a little ways back from the ball joint cup. So the ball joint is only held by a single 1" tube.
However you slice it, this car has the target of 1000lbs lighter than the current car...which would be right around #2600 race weight. But I'll be happy with anything sub #3000. That itself reduces the loads on the suspension by a big margin.
Great work going on, love this direction.
I know I'm not the only one who ends up in this place.
Invited to KOTM again!
Got out to do some testing yesterday for a knock off the rust autocross event. Two courses and unlimited runs!
Which I utilized completely until some bad rear lockup hop exploded an axle drive flange.
Takeaways for the day were:
I was rusty but got fast quicker than a lot of other people.
Alternating courses on the fly as good for exercises in looking ahead and not just going off course memory
I didn't stop to make shock or tire pressure adjustments because of the constants line/runs (sub 5 min cycle time all day). And this really highlighted the areas of performance the car is lacking. Too much unloading the rear on the brakes, front can't take a lot of slip angle without getting pushy, sliding the rear...while easy to control interrupts my rhythm.
The barely above freezing temps didn't help any of the above... especially tire performance. But I think the low grip made it easier to see that unloading the rear is really hurting my times and making short shutdowns after a fast finish sketchy.
Game plan right now is stiffer front springs and give up some on throttle suspension grip for less unloading on the brakes. And going up to 315s all the way around to better handle the weight of this car. Hopefully more tire evens out grip changes on the rear and helps with the slip angle understeer on the front
Is there sway bar tuning that can help weight transfer and/or front end pushing?
In reply to 4cylndrfury :
Front is a splined bar and i do have a couple different ones. Currently have my softest option in the car. Not running a rear bar due to the gear type diff needing both tires on the ground to have drive
Basically the car turns but a few degrees before I get to where i want to be on the steering wheel I can feel it just stops turning more and scrubs the fronts.
Put on some bigger tires yesterday to try something different for autocross at BRMP today.
They are 295/40/18 vs the 275/35/18 I've been running for years. I got them for free! Not a brand I was after but the size is what I wanted to try.
I had only some hopes about how the car would handle with the bigger size and being a less sticky tire.
Overall it was a success. After 6 runs I was among the usual suspects for speed and ranking. Then I kept adjusting the shocks and it kept getting better. Shaved another .8 sec in the afternoon, some of that because of warmer temps but it was handling better too.
No trace of the passed slip angle understeer where I wanted to turn the wheel to. And it could take way more compression setting in the front coilovers than I've ever been able to run here before. It helped me get the adjustment so that I could try for some better on the brakes performance. Not as much as I want but it was progress.
Just realized I completely left out two interesting things that happened while at BRMP. First was another driver buying the BRMP shirt (which has my car on it) coming over with a sharpie and asking for an autograph...First time that's happened.
Second was a guy showing up specifically to find me....turns out he was watching the Gridlife South Carolina Livestream a couple weeks ago and found out about BRMP that way. He's local to the track and hadn't heard anything about it before but drives by off and on. Made a point to come out and "say hi to the local celebrity". Lol
I'll see if i can find the clip. Gridlife interviewed me back at Autobahn last year and it came out pretty good.
That's freaking cool. Congrats!
In reply to 4cylndrfury :
Thanks.
Here's the shirt
To continue development and testing before the next autocross I've decided to up the front spring rate. There was a time when I was running 1200lbs with a .5 motion ratio. Now the ratio is .66 and I've been on a 750lbs rate for s few years. Going up to a 850 spring is the plan.
This should help with front end dive and the resulting camber gain on the brakes that's been hurting performance. The camber curve is great for the corners right now so I don't want to compromise that with a static or dynamic change. Hopefully this will also keep more weight to the rear axle on the brakes as well.
Great job on the interview! It seemed really well done.
The stiffer springs proved an improvement today. Also tested a couple different 3rd link positions in the afternoon and was in the fight for FTD. I think when it was all said and done with all the runs everyone got I missed out by a few tenths.
Then got asked to drive an S14 setup for drift that was there autocrossing too. After a couple laps I got a clean one in and was only a tenth off the Cutlass. It made speed very differently and I came away with a few new ideas.
First of which is throwing on the 250lbs rear coils in place of the 300lbs that was on there.
Nice drive though
Set off for another day of autocross this morning.
This was a good benchmark event as another entrant in CAM T is someone else who's going to KOTM and in the same class. I was trailing by 2.7 seconds after the morning runs but closed up to 1.8 in the afternoon. Getting some ideas on where speed was on the course played a big part as well as shock adjustment and dumping the rear tire pressure to 19lbs. It actually started hooking up well. Side effect was a bit of squirming in the rear but it was well worth it as I picked up 1.2 seconds and backed it up on a second run too.
So many new ideas about how the car could be set up going through my head.....
I love the idea that driving a car set up for a totally different type of competition can change tuning perspective. This is a really fun thread.
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