I'll be posting about the CRX as soon as I get it back on track.  For now it's the FiST I'm currently running.  Feel free to jump in with autocross events.

Got a great running season points battle in the Mid South SCCA region with 3 other drivers - Doug with his 09 F Street M3, and Steve and Alex codriving first a late model GTi in G Street and lately a fully prepped STR Miata.  I had been finishing 4th or 5th behind the others and decided I needed to step up my game.  Got some new tires for the FiST and focused on driver mods.  The last three events I had a 1st, 3rd and 1st.  Yesterday I set a great time and ended the morning session with top PAX.  I was unable to improve in the afternoon but as luck would have it the others got faster but not quite fast enough.  Got the W and jumped past Alex and Steve in the points race.  Currently 2nd and hoping I can hang on and catch Doug for the PAX Championshio repeat.

Week 4 of the Summer season.  Still qualifying poorly but I managed to move up from 13th to 7th in the main.

Been heading over with a couple of buddies, getting back to town early afternoon.  Great times.

Points should be out soon.  I was 9th of 20 after last week but I should move up this week.

How’s it sound?

exactly the same as it did before :-)

Got the exhaust mostly squared away.  Need to take it back off and finish weld the bits.  

Going to see what it sounds like tomorrow.  Didn't get to it today as my 10 year old Ecoboost F150 needed some attention in the form of a new throttle body

Ok, got the parts for the exhaust.  I ordered the wrong flange so I went with a flexible coupling.  Had to cut and reweld a section of new pipe but it looks good now.  Going to button it up hopefully today.  Header sits about 3 inches lower than the downpipe, which is understandable since it's bigger.  I'm thinking it might be a problem if I have an off pavement excursion, although that hasn't happened in a while.

Tried out my new auto dark welding hat.  Welds are 10x better now that I can see wtf I'm doing.

Ok, put the shifter back together today. Decided not to replace the bushings since the rubber ones are still in excellent condition.  The issue with the sloppy shifter was the spring pin that holds the linkage to the trans.  It had fallen out and I used a bolt which wasn't quite large enough.

Ordered some parts for the exhaust.  going to try to weld a flange one the end of the header.  If that doesn't work I'm going to remove the cat and use a straight pipe and a flexible connector between the header and exhaust pipe.

Also ordered some parts for the spoiler. Not a priority but I'll still pick up parts.  

Really once I get the exhaust and the cold air intake squared away the last thing is the stripped bolt on the rear mount.  I might have this ready by august for a test and tune.

This is probably already common knowledge but just in case...

The pin that holds the shift linkage to the transmission is an 8x20 spring pin, pretty commonly available from McMaster Carr or Granger

I was just thinking on my way to the liquor store, I think the biggest reason it's taken me so long to get this car straightened out is that the weight I removed changed the balance considerably.  

The car was well set up when I got it.  My aunt didn't know the setup as my uncle handled all the mechanical stuff and he'd passed a few years earlier.  Whoever did it knew what they were doing.  It was fast.

But I took 250+ lbs off it including removing the roll cage.  But I didn't do any kind of baseline model.  I should have but I was learning all this.  I'd do it differently now.

Anyway, I'll get it.  It's taken me so long because I just got burned out after it broke the last time.

What type of Kart do you race?  Did a mini enduro, work team building event, years ago in basic karts.  The shifter karts look like an absolute blast!

 They are just basic Sodi rental karts.  Pretty slow so momentum is important.  I've done a few enduros too.  Endurance Karting uses karts that are a bit faster.  DKC has some considerably faster rental karts but you have to qualify with a certain lap time in the rental karts before they'll let you drive one.

I've never driven a shifter kart but I've driven a KA100 and it's fast.

I was figuring based on your data my rate was a little low in the rear.  Mine is setup for time attack, but these larger tires and stager setup have really played with things.  I do not like running a tone of bar, always feel like it makes the car more twitchy.

I think it depends on driving style.  I've seen autocross setups on these cars with a ton of front spring - like 31mm bars plus two ARBs and relatively light rear springs.  Seems to me it would understeer hopelessly but the car was quick.

New track opened this spring in Villonia Arkansas.

Heading there tomorrow early for league racing.  
Made one race last season, started pretty far back in the field due to a poor qualifier but managed to move up to 13th in a 20 driver field by the end of the main.  Hope to do a little better this time.  It usually takes me a few tries to get the track right.

Last season was thursday evenings, making the 3 hour run from Memphis pretty tiring.  Saturdays only require me getting up at 5 which I do anyway most days.

nice

In for results.  I’m running 30mm bars and 600lb springs with 3 degrees of camber up front.  My pyro analysis showed good temps across the tire surface.

 

im considering upping rear spring rate as I’m not getting as much rotation as I would like.  Tires impact this so much as well, but for my setup I feel I need a bit more in the back.

I plugged your spring rates into my model just for grins and came up with frequencies of 2.94 and 3.17 which is higher than most seem to recommend for autocross but more or less the same spread f to r in terms of frequency.  Mine with 27.5 and 550 is 2.55 and 3.03 which gives the rear more spring relative to the front than your setup so I would expect maybe neutral or oversteer but it all depends on driving style.

All that is going to change once I add the aero and start messing with it.  I wish I could find a good online calculator or at least a guru of sorts to kind of point me to a ballpark initial setup.  I have a pretty good idea how much more rear grip I can expect from a spoiler but I'm completely in the dark as to the effects of a front splitter and air dam.  An air dam doesn't just make downforce in the front, it changes the entire car by restricting air entering the underside of the car from the front.  I'm limited as to the size of the front splitter, and actually the spoiler too but the spoiler can be 9" tall and angle is unrestricted so I'm envisioning maybe making a series of test mules of different heights.

In for results.  I’m running 30mm bars and 600lb springs with 3 degrees of camber up front.  My pyro analysis showed good temps across the tire surface.

 

im considering upping rear spring rate as I’m not getting as much rotation as I would like.  Tires impact this so much as well, but for my setup I feel I need a bit more in the back.

If it's just a little bit you need, try a little toe out in the rear.  You can add some shims \around the four  bearing assembly bolts.  Adding a like 1/32" to the front two would give you maybe 1/16 toe out, or adding to the bottom you can get some neg camber.  I had it set up with a little toe in but I'm going to leave the shims out and add later if I need to tune

I've been workign on a write up but I keep having to go back and revisit things to get it straight in my head.  It's been 4 years since I last looked at this.  I'm currently working on other aspects of the car, and suspension setup will be the last thing.  I'm just going to leave it where it stands for now

Based on the work I've done so far with the various models and calculators, when I get to that point I'm going with the following setup

27mm front bars

550# rear springs

front and rear ARBs

front height set to -3 degrees on the LCAs (slope up toward the wheel)

no aero

Once I get it set up this way I'll take some measurements off the car such as initial camber to see how it compares to the models.  I'll also pick up a pyrometer to check tire temps as I have a hunch that the initial camber, if it matches the model, will be enough, and I'll be able to swap out the camber plates for the strut bar.

I expect this to be neutral handling with the least amount of body roll.  If I need to tame any understeer I can add more rear spring.

aero will come later

I almost forgot, removing weight from the car necessitates remeasuring the center of gravity height.

I'm back on the CRX now.  I've reduced some more weight and swapped in the HF axle, and updated the model to match.

I've got to go back to my notes and continue posting the results of the suspension model.  Briefly, what I discovered with the front model in Racing Aspirations was that the least body roll was achieved with the front roll center slightly below the ground level. Beyond that, the virtual lever arm got longer and body roll increased.  In other words, going too low on the front increases body roll.   Adjustment to the optimum RC location resulted in an LCA angle that sloped UP toward the ball joint rather than down as the conventional wisdom dictated. I think -3 degrees was the angle I ended with.  This minimized body roll and maximized static negative camber at around -2 degrees.  I decided that was a good starting point for adjustment and will go with that in the initial setup. 

I used two different model sources to model the entire car.  DGATW and a spreadsheet I downloaded (from where I can't remember, a rally team iirc).  DG recommended 400# rear springs and the other model nearly 800# because it recommended a much higher rear frequency based on the calculations it made.  Right now it has 550# springs.  I'm undecided but 800# seems way to high and 400 I've already determined was too low (but had rear aero at the time).

Initially I'm going to go with the 400s and no aero and see how it handles and go from there.  

Sun roof is on my list as well.  I thought there was an old post that found it was 35 lbs that you save.  35 or 45 it is still in the highest point on the car.  I cut the roof off of a non sunroof car to reskin mine.

 

i want to do mine for a few reasons.

1) it doesn’t work any more.

2) due to headliner shape, for tracks, my helmet rubs and bumps on right hand turns.

3) weight is in a bad place.  Getting it lower and in right rear will improve balance.

It was about 33# including the headliner.  I have one from an HF that I'll put back in that's lighter.  I thought I'd have to get a roof from one without the sunroof but the movable panel is sheet metal.  It will require some modifications but will work.

Also removed the stock rear spoiler for another 10#.  I'm adding a custom spoiler so don't need it.  I've been keeping track of weight and it's now 1681

Yes, and next up for weight reduction will be removing the sun roof and replacing it with a plain panel.  Between the mechanism, motor, movable panel and headliner, it should take another 45# off.  I've been keeping track of weigh reduction and I should have the car at around 1650# after that.

Swapped out the rear axle to the HF one.  Saved 12# and got rid of the internal torsion ARB which I couldnt quantify in my suspension model.   I can easily make up for any loss of roll stiffness by changing the spring rate. 

In too learn.  I have never run aero on mine.  Three others that I know, long time racers of 1st gens, one stock chassis and other two full tube.  They ran splitters.  They also ran on full sticks.  I could ask for a measurement.

There are class limits in SP - front aero is limited to between the front of the wheel opening and the front edge of the bumper and the outermost edge of the side bodywork, rear spoilers 9' tall and must not extend past the outermost edge of the bodywork.

Seems to me you would max out the front and adjust the rear to balance.

I've run a rear spoiler for years - ever since I tried a suction cup one a friend used.  I was coming around a sweeper noticeably faster than I previously had (spectators confirmed this) when the outside section came off.  The car immediately spun.  Spectators confirmed this and the photographer captured about 10-12 photos in sequence.

Might be the reason I've run 500-550# springs in the rear.  DGATW suspension calculator recommends 400#, but the car understeers badly.  Hoping maybe a frojnt splitter will balance that out.

I'm about to break out the suspension modeling worksheet again. There is a thread here, partially done.  Going to finish that up but a summary of the results is that I ended up with more understeer than predicted, I suspect due to my spoiler.  So I'm going to address the aero question as well.

Looking for resources on balancing aero.  You can use a suspension calculator to get somewhere in the ballpark for suspension setup, but is there something similar for aero?  It would be nice to have somewhat of an idea of how big a splitter and spoiler can/should be and how to balance them with each other for the optimum effect.  I figure there will be some testing and tuning with regard to the suspension to get the optimal setup.

What has anyone here used as far as calculators and actual setup?

Just got word from Kirk Racing.  My header is on the way.

Going to reinstall the HF rear axle, replace the shifter bushings, build a new cold air intake, address the stripped trans bolt hole, and go around the car fixing little things and cleaning it up.

Then I'll reevaluate the model and set the suspension up.  Might try to take it to an out of town event as a test and tune since I'm in 4th place points wise in the Fiesta

took it for a short test around the yard.  No shaking.   Seems to have been fixed at the moment.  I think the rear mm was the cause.

Need to take it for a longer test.

On a sucky note, when I was retorquing the rear mount bolts on the tranmission, the lower one stripped, so now I have that to deal with

OK, replaced all three mounts.  Turns out they were all broken.  The rubber was just so old it was basically crumbling.  I also discovered that three transmission bolts were loose and one had fallen out.  There was a lot of movement in the transmission, obviously.  I think these are all a result of the shaking rather than the cause.  The LH axle seal is leaking, so I'll bet the RH seal is as well.  There is an opening just big enough for slung oil from the RH seal to go into the belhousing so right now I'm going with that as the cause of the shaking.