kolosy build / track journal-ish

[kolosy]

Originally Posted by F4rmost

Theoretically, with the cold start delete, could you remove the SAP, then just cap the T and the port on the intake?

If you remove the sap, then you tank the T with it. Just install the factory block off plates on the heads and cap the intake port, yeah. There are factory parts for all that (no sap in Europe), but they’re getting hard to come by. They’re a guy on the forums that 3d prints the intake cap. It’s what I’m using and it works well.

[F4rmost]

Originally Posted by kolosy

If you remove the sap, then you tank the T with it. Just install the factory block off plates on the heads and cap the intake port, yeah. There are factory parts for all that (no sap in Europe), but they’re getting hard to come by. They’re a guy on the forums that 3d prints the intake cap. It’s what I’m using and it works well.

I am just trying to avoid the time to put the blanks on the heads, as well as save my sanity LOL.

It seems they are a pretty large pain to remove.

EDIT: The cage looks fantastic.

[kolosy]

Originally Posted by F4rmost

I am just trying to avoid the time to put the blanks on the heads, as well as save my sanity LOL.

It seems they are a pretty large pain to remove.

EDIT: The cage looks fantastic.

I mean sure, you could probably do that. Not sure it’s worth it though, the sap doesn’t weigh very much and that’s all you’re really getting. Not that the rest weighs all that much either, and yes, getting the blanks on there is a nightmare.

And thanks

[kolosy]

Well, I think we’re coming out of shakedown mode. Despite questionable weather, I snuck 3 days in already, including a full open track day at autobahn.

Some observations:
- on old tires and having sat on my ass for 6 months prior, I plopped down a pr by half a second on my first session out at Blackhawk farms. (I then proceeded to have a change of underwear moment in the second session and backed off a little). Surprise surprise, a net loss of 350 lbs makes for a faster car lol
- I’m definitely seeing better braking behavior (though I did get two ferodo ds3.11s to delaminate, so that’s a thing). Temp strips stayed in the middle the whole time
- holy understeer, Batman! I think it’s part the cg shift with all the weight stripped out, part the heat cycled tires but man oh man it’s just a plow right now. That’s probably the biggest thing I need to focus on going forward.

I got the wing logic wing mounted with a custom bracket I designed that uses the factory trunk hinge mounts (on the trunk, not on the chassis) and that seems to have worked well. Did add a couple of hard bump stops so that the down force doesn’t just push on the latch and nothing else. A couple of nutserts and m8 bolts seems to have done the trick there.

Quiet happy with the start of the season, but definitely lots of tuning ahead.

[roastbeef]

holy smokes, what is the width of that wing? 78"?

[kolosy]

Originally Posted by roastbeef

holy smokes, what is the width of that wing? 78"?

Haha 72”. I ordered a tinted helmet visor and the distributor shipped this instead by accident, then offered to let me keep it at cost.

[roastbeef]

my wing is 72" and this looks to be two to four inches wider on each side... maybe its an optical illusion.

[kolosy]

Originally Posted by roastbeef

my wing is 72" and this looks to be two to four inches wider on each side... maybe its an optical illusion.

it's definitely 72", I measured it when I was getting the brackets welded on.

[bigjae1976]

Originally Posted by roastbeef

my wing is 72" and this looks to be two to four inches wider on each side... maybe its an optical illusion.

He has a sedan which I believe is slightly narrower than a coupe. Sedans definitely look a little more narrow.

[bigjae1976]

Originally Posted by kolosy

- holy understeer, Batman! I think it’s part the cg shift with all the weight stripped out, part the heat cycled tires but man oh man it’s just a plow right now. That’s probably the biggest thing I need to focus on going forward.

Higher speed turns or lower speed turns?

If you're understeering in lower speed turns, I'd first check data to make sure you're trail braking. If yes the lower the front spring rates.

Aero is not making nearly as much downforce as you think below 60mph. The wing shouldn't cause a bunch of low speed understeer unless it is causing a LOT of high speed understeer.

[kolosy]

Originally Posted by bigjae1976

Higher speed turns or lower speed turns?

If you're understeering in lower speed turns, I'd first check data to make sure you're trail braking. If yes the lower the front spring rates.

Aero is not making nearly as much downforce as you think below 60mph. The wing shouldn't cause a bunch of low speed understeer unless it is causing a LOT of high speed understeer.

It’s been a couple of weeks now so I don’t fully remember but the turn I’m specifically thinking of is a 90* coming off a straight. I’ll pull the data again and look. This is why I didn’t think about the wing causing understeer in the other thread btw, my expectation was that it wouldn’t do much at lower speeds.

[bigjae1976]

Originally Posted by kolosy

It’s been a couple of weeks now so I don’t fully remember but the turn I’m specifically thinking of is a 90* coming off a straight. I’ll pull the data again and look. This is why I didn’t think about the wing causing understeer in the other thread btw, my expectation was that it wouldn’t do much at lower speeds.

I've been playing around with wool tuft testing. I've learned a lot and the key thing I've learned is most people don't know shit about aero.

But you can see how the string gets exponentially more excited as speed goes up. I think it is squared or something? I'm asian so I should know but I'm really just a fake asian. But its not a 50% increase in speed results in a 50% increase in downforce. Its something like 100% increase. So if you're getting 100lbs of downforce at 100mph, then it is a LOT less at 50mph. Again, fake asian so someone else will need to do the math

[kolosy]

So I think I’ve solved the understeer issue. Turned out to be pretty simple — get the alignment and corner balance done by a shop that knows wtf they’re doing. I had been going to a shop that was close enough to me where I could just drive the car there (I live in lakeview, which is a neighborhood of Chicago pretty much in the middle of the city). And it appears to be a legit race shop that does Porsches and bmws. The last two times I’ve gone for alignments there though it’s taken them something like 8 hours and there was lots of complaining. On this last go round, it took them over a day to align and corner balance it, and they charged me $1500 for the privilege. I like the guys (so I won’t name and shame) but that sealed for me, never going there again. Found another race shop still nearby but have to trailer there. $500 for alignment and corner balance, and confirmed that the ride height was all jacked up and the alignment was off by a wide margin. Oh and that they didn’t use driver ballast when they corner balanced it.

Anywho. Went to Road America recently to test it all out. Car feels super neutral now, with a touch of oversteer. This is with the same aero and sway bar settings as before, and 1/16th out in the front and 1/8th in in the rear. And about 1/2” rake.

Also got rhe forgelines to fit in the front with a 15mm spacer and 285 Re71rs tires. They poke out a bit but don’t rub.

Very happy with how the car ran this time around. It’s my first time running the kink since I lost the G82 there and I was being SUPER paranoid through it. Even so, I managed a 2:38.8, only 4 seconds behind my best in the G82. And that’s a car with 1/3rd more horsepower, awd, and an idiot that was going too fast through the kink behind the wheel.

Oh and Randy Pobst was there and I got a ride with him. That didn’t hurt either.

[jmeenach]

Did I see your car on Race Cars For You?

[kolosy]

Originally Posted by jmeenach

Did I see your car on Race Cars For You?

Yeah, probably. Exploring options And also I think I just snagged an M2cs allocation 🫣

[former 240 s14]

So going from double to single hump, did you do any programming of anykind for dash lights etc? Also, did you weigh the dashes against eachother? I am interested in doing this also, just not sure on the way to do it with as little problems as possible.

Thanks!

Rubin

[kolosy]

Originally Posted by former 240 s14

So going from double to single hump, did you do any programming of anykind for dash lights etc? Also, did you weigh the dashes against eachother? I am interested in doing this also, just not sure on the way to do it with as little problems as possible.

Thanks!

Rubin

In my case, the only coding I’ve done so far is to code out the airbag module so it doesn’t turn on the airbag light. Dash is clear. Now, if you scan her, she’s PISSED. But none of that seems to matter.

If you want to keep audio (seem to remember you saying you had some speakers left) that’s a whole different ballgame. Also the hvac controller is an different shape and the support bracket for it is different too. None of that mattered to me, but just fyi.

And I can’t imagine they weigh materially different.

[amg6975]

Easiest way to make big changes is change your VO codes and then default code everything. From there, put any custom changes back. Half of the modules in my car are gone and it doesn't care, only code is the DCT not being able to see the seatbelt.

[kolosy]

Originally Posted by amg6975

Easiest way to make big changes is change your VO codes and then default code everything. From there, put any custom changes back. Half of the modules in my car are gone and it doesn't care, only code is the DCT not being able to see the seatbelt.

So.. other than engineer ocd (which I respect and share), is there a reason to care about codes that aren’t causing dme/dct issues?

[amg6975]

Originally Posted by kolosy

So.. other than engineer ocd (which I respect and share), is there a reason to care about codes that aren’t causing dme/dct issues?

Probably not if everything is working fine.

[M3SQRD]

Originally Posted by bigjae1976

I've been playing around with wool tuft testing. I've learned a lot and the key thing I've learned is most people don't know shit about aero.

But you can see how the string gets exponentially more excited as speed goes up. I think it is squared or something? I'm asian so I should know but I'm really just a fake asian. But its not a 50% increase in speed results in a 50% increase in downforce. Its something like 100% increase. So if you're getting 100lbs of downforce at 100mph, then it is a LOT less at 50mph. Again, fake asian so someone else will need to do the math

Downforce and drag are proportional to the square of velocity; e.g., equation for downforce is Fd = 1/2 x rho x Cd x Ad x V^2 where rho is the density of air, Cd is the coefficient of downforce, Ad is the area of downforce and V is the velocity. So 50% downforce is equal to say 1.50 (unit of force) at 50 mph so the downforce at 100 mph would increase to (assuming rho, Cd and Ad are fixed values)

Fd = 1.50 x (100/50)^2 = 6.00 [force unit]

The increase of downforce is (100/50)^2 = 4.00 - downforce increases by a factor of 4.0 for an increase in velocity of a factor of 2.0.

[kolosy]

speaking of downforce.. ended up having to decrease the AoA on the wing somewhat, and that definitely helped high speed stability. i need a real splitter to run anything more than i'm at now. i went back to blackhawk farms and the back straight has a kink in it. normally, you can either coast through it or stay on power through (depending on your pucker factor resistance). before adjusting the wing i had no steering without brake application which is slightly terrifying at 120+.

also, kinda fun -- my PR in the E90 there was a 1:20.4. in the G82 I did a 1:18.9 last fall. this time around i put down a 1:18.7 in the E90. same tires (RE71RS), too. my buddy in a 991.2 turbo s was p*ssed at me for passing him lol.