91banditt2

iTrader: (1)

I look forward to your video at Rockford, It's been a dream of mine to get my car on the road course at Mid Ohio, it's probably not gonna happen this year, I'm hoping next year.

Mid-Ohio Sports Car Course Track Event September 29-October 1, 2023 - Third Generation F-Body Message Boards

raptere

First road course in the camaro was officially put on the books last Saturday afternoon at Autobah racing club in Joliet IL. It was pretty amazing and I was able to drive the car home which is a huge plus! I was initially a bit nervous about getting on a proper track, but it ended up not being bad at all. The event ensured 8 runs, four in two separate run sessions. Then at the end of that they opened up the track for more fun runs. I ended up totalling 13 runs in the time I was there! Not bad for a $95 entry fee!

Biggest challanges:
- Determining breaking points and turn in points is a whole different game, especially when youre actually getting some speed, made it up to almost 89 mph. I started at the first brake marker if the turn had them, then kept pushing it farther and farther till I got very close or touched the far curb on turn exit.
-Had to time my turn to hut the apex curb at the right spot, and actually touch it.
-unfortionately i found out at the end of the day there was one turn people were only lifting on, and not braking, so i lost some time there...

Vehicle findings:
-We were asked not to get out of our cars in the pit lane where we qued up for our next run, so we had to plan accordingly. I was told to expect 4-5 psi of tire press rise during the 4 run sessions. I've got the actually number in my notes I'll update later.
- It did seem like this type of higher speed track racing does build more temp in the tires and brakes, and probubly consumes them a bit more than autox. Luckily I had no issues with brake fade or overheating of my crappie 360 tread ware summer tires, that I could notice.
- possibly my BIGGEST TAKEAWAY was that on heavy breaking I was locking up my rears. I've always been able to feel the rear get loose on hard braking, but a friend told me I was actually smoking them... This means the spring I swapped out in my brake valve is too tight. I'll have to do some calculations and either shorten the spring slightly, or just get a proper manual perportioning valve.
- Amazingly with the accelerometer on my phone through the track addict app, it told me I was achieving a peak lateral g's of 1.16! Does this make sense with substantial suspension upgrades, or is it bogus? Looking on the web a viper acr only gets lile 1.18 or something...
- My best 0-60 was 5.6 sec, so I guess thats decent?

I'll try to get a video or two up soon...

91banditt2

iTrader: (1)

I was considering doing the spring mod, I decided to go all in and put in a adjustable proportional valve

raptere

Just uploaded my best run from the Track Sprint at Autobahn:

BBU.COM

Awesome looks like a lot of fun, I had one lemon car we sponsored a few years back , that crew put the brake bias valve in the interior, they adjusted it as it ran lower on fuel, so less ballast, less rear brake, Shortening the spring wont reduce the rate , actually I think it will increase it - I`d do the adjustable

raptere

So far with my track sprint event, I don't think It would make enough of a difference burning through fuel to need to compensate for brake bias mid event... interesting idea though!

I agree with you, partially. All variables being the same, cutting coils off a spring does increase the spring rate, but it also reduces the free length so after reinstallation, its starting condition will be under less compression length, so the initial force will be lower than the as manufactured spring. Im pretty sure that while the spring rate will be slightly higher, the actual force will never exceed that of an un-modified spring for a given length of compression.

Shortening one of the springs I have is free and I have a couple extras if I go too far. The brake bias adjuster is a couple hundred bucks, so I'll give the spring a try or two, then if im not happy, I'll get the aftermarket valve...

I am trying to figure out how the brakes should function. I read somewhere you want the rear brakes to lock just slightly before the fronts, but how do you figure put when that happens? Have a friend take video? It was only at the event last weekend that people told me they saw the tire smoke... I guess now that it is doing it I can feel the rear end get loose, so maybe I do it by feel?

raptere

I just ran the actual calculations on shortening my 1NCR5 spring in my brake bias valve. As expected, as you cut coils off the spring rate increases, but the free length decreases as well, so the total force at a given compressed length decreases. I just arbitrarily ran my calculations at 0.5" of compression. I do not know if this is actually the level of compression in the bias valve, but since it is consistent for all springs, the results shown are proportional... Since I still have 4 more of the spare springs, I may give my first try at -0.5 coils and see how it feels. If it's too much I can always cut less off a fresh one, or keep cutting if I'm still locking up the rears first... My numbers weren't dead on with the advertised specs but they were close enough for me to think I got the calculations right, but they are not using the exact same material constants as I found online... I therefore when back and determined an optimized constant for each material type so my numbers matched the advertised ones. (I'm also assuming the factory spring is music wire)

I'm trying to remember; do I need to bleed my brakes after swapping the spring out???

QwkTrip

iTrader: (22)

There is some spring data in Post #4 of this thread that might be helpful. And Post #2 shows a method to estimate the proportioning curve.

https://www.thirdgen.org/forums/brak...ng-torque.html

QwkTrip

iTrader: (22)

Fronts should lock first. Car can swap ends if the rears lock first.

For quick test, you can drive fast around a curve and hit the brakes and see if the rear slides first. This is an inherently stupid thing to do so be careful. But it'll let you know.

If you do straight line braking on the street then you'll probably end up dialing in too much rear brake and lock it up at the road track. The street just doesn't get the fronts hot enough. When you go to the track the fronts will fade more and then the rears will lock up.

raptere

I got the new torque converter installed! It's a pretty significant difference. Still very streetable, everything just happens at a bit higher RPM. I also swapped to the next lighter weight in my shift governor while the trans was out, and now I'm getting ~5400 rpm WOT shifts, which I would say is about where I want it for now.

Video of even Sunday with the new converter and governor tuning. Definitely seemed to keep the RPM's up more and in the power band better, even with the slower corners!

raptere

Now that my second season of racing has come to an end, and I was left to twiddle my thumbs for the cold months here in the Midwest, I decided to do something about it...

I'm building a Sim Rig for iRacing! Hopefully this helps me continue thinking about the fundamentals, looking farther ahead, trail braking, and other topics that hopefully will carry over in some small way. If nothing more, it's fun! Challenging... but fun!

More to come!

QwkTrip

iTrader: (22)

Oh, I'm watching this! That sounds like a lot of fun.

raptere

Man, this is tough! I decided to go with iRacing, which is a true and brutal racing simulator, definitely not a game like Grand Turismo, and other video games.

I also decided to get some decent mid grade gear from Fanatec, which had great black Friday deals, but their order processing was just atrocious! My order placed on Nov 28, was just shipped from Cali today... Hope to have it the 26th. Lot of customers furious about Christmas gifts that aren't going to make it in time...

I ended up grabbing an open box Logitech setup to use while I've been waiting. I do expect the Fanatec stuff will be a large upgrade!

raptere

Got all my mid level direct frive stuff from Fanatec a couple days ago! Load cell brake is way better than the potentiometer style. The 8 n-m of torque is no joke, makes it legit challenging. Alcantara wheel and feel of the shifter paddles are really nice too, way better!

Fords88Bird

I do want to try some auto x racing in the future.

Passmenow

My Iracing sim is a big help between races.
I can practice and maintain my left foot braking sensitivity at home.
Also a few tracks I race on are on Iracing.
After 400 laps on the sim when I get to the real track my first session feels like its my 3rd session.
Sim is a big help.

Tom 400 CFI

Start now.

raptere

If you want to try it, just do it. In the spring sign up for an event, you can usually pay for a weekend membership so you're not investing a lot of money. Let them know you're a novice, and everyone will help you out. Just use masking tape for numbers and give it a shot with whatever state your car is in. You'll either find you love, it which I think you will if you're on this board, or you'll find it's not for you... which I doubt...

raptere

That's awesome to hear! Very nice looking setup. I wonder have you been running flat triple monitors all along, or did you switch from another configuration. I happen to have the spare TV but I wonder how much of a difference the scree setup makes... I have raced at Sim Racing Chicago a couple of times, and all their setups have curved triples, gives a very immersive feel. They also have articulation for the rig, and but kickers and everything else you can think of! Very awesome, but actually made me motion sick the first time. Luckily, I do not have that problem with my rig at home...

Passmenow

When I got the sim 10 years ago flat screens were more common.
I do have VR goggles but can't get my prescription glasses under the goggles, sometimes the VR can give me motion sickness too.
Have the butt kicker and the cars and tracks are awesome on Iracing.
Not sure about using a TV screen but try it might work well till you choose something else.
A single curved screen or triple curved screens sound cool like to try those someday.
Lucky I have an IT friend that keeps my sim tuned and running well.
When I have friends driving the sim I hide the keyboard so no one can accidently corrupt my set up.

Tom 400 CFI

^What he said^....except that he's in SOCAL, so they might be racing right now.

raptere

Happy spring everyone! I was supposed to go to my first event this weekend, but out of the blue, my car has decided to become completely undrivable. Litterally it surges and stumbles constantly, even at idle, and if I try to give any throttle it just shudders, shakes and gets worse. Afraid to even back it out of the garage for fear it won't make it back up the driveway...

All the details here, any ideas, please post there:
https://www.thirdgen.org/forums/diy-...ml#post6533109