[agent008]

@ConeHugger01

Have you noticed a large change to the brake bias at all??

In theory bhe should, shouldn't he? Otherwise it would mean that the improvement on the front stopping power is not significant.
Perhaps the kingpin of the issue is fade/heat disspation ability compared between stock and BBK.

 

[ConeHugger01]

@kgschlosser None that I can detect. Now, I hadn't driven the car very much before it all got changed. But braking is good and straight, I don't detect the rear end getting loose under heavy braking even during autocross.

 

[agent008]

@kgschlosser But braking is good and straight, I don't detect the rear end getting loose under heavy braking even during autocross.

Well, I imagine rear not getting loos would be an expected effect of improving front brakes and leaving rears stock, but then again, I believe the stock brakes also have a good F/R balance already..?

 

[kgschlosser]

This is what I am wanting to know also.

The OE front rotors are 11.66" in diameter and the brembo kit has 12.5" diameter front rotors. If memory serves that should be close to 25% more braking force. I would think that the car would want to understeer when cornering and braking heavily. It all depends on what the OE bias was.

 

[ConeHugger01]

2021.07.10
At autocross I had a big tank slapper at the finish line at ~60mph and when I regained traction/control, I was headed straight for a line of 7 cones, and hit them head on.

Video: 2021.07.10 Cone Killer Classic - 7 cones

And I collected 5 of them under/in front of the intercooler, this is the damage:

It's still functional I think, I didn't push it hard after that, but car ran OK on the drive home. I estimate it's losing 10-15% of volume perhaps.

I tried to install the Hahn giant intercooler I have, and aside from being super heavy, the tubes on it are not long enough and the hose couplers didn't fit as well as I wanted them to, and had a huge leak.

 

[kgschlosser]

Considering a skid plate to replace the plastic?

I also do have an OE CAC if you need one. The bottom plate has a small ding in it nothing major like yours. It's only the very bottom solid plate and it's tweaked up a little bit. I am thinking 100.00 + shipping for it if you are interested in staying stock. I can get you some photos for it. let me know.

 

[ConeHugger01]

Yeah I was considering a "cow/cone catcher" over the winter but it was lower on my priority list. Maybe I will have to seriously work on that now!

 

[agent008]

Sounds (and looks) like it was lot of fun... until your car got cone hungry. Well, even then I'm sure it was still fun.
It's a shame there's no autocrossing in my area. The only kind of event around here is drag racing which is kinda boring in my view.

 

[kgschlosser]

@ConeHugger01

As your username implies. you like to get up close and personal with the cones.

However I thought the context was supposed to be getting close to them, not literally hugging them.

 

[ConeHugger01]

Weighed the car: 3076, with race wheels 3050, that's about a 52/48; I was thinking/hoping I'd be closer to 50/50.
I can't think of anything significant to remove from the front I don't need - maybe the AC, I read somewhere that's only ~50 pounds.

 

[JohnWR]

Have you moved the battery to the trunk?

 

[CaTalyst.X]

2021.04.03: Wheels, lugs.

Tires test fitted. The wheels were a tight fit on the front wheels, there was a lot of friction to push them on even partway. I took a dremel sanding cylinder to the outer edge of the hub nose to clean it off. It only needed about 0.1mm removed for a better fit.
View attachment 112082

Lug nuts: Supplied from Motorsport-Tech stubby nuts have 6/7 threads; short size from Advanced Auto (Dorman) have 10/11 threads, Trans Am lugs with the outside threads for "fancy lugnut covers" have 13/14 threads. Stock Sky lugnuts are in the 9/10 range.
View attachment 112083

The medium length are perfect for the rear adapters. Notably both the stock Sky wheels and my BC wheels have recesses behind the areas between lug holes.

View attachment 112084

View attachment 112085

View attachment 112086


In other news, I got the front bumper better aligned and tightened up. Hopefully no need to take it off again for a while. The wheel well covers were reinstalled, using screws and flat nuts instead of the single-use christmas trees/push plugs.

Didn't you order custom wheels? Why the need for spacers?

 

[marksbug]

I would put a lion or whatever there called light weight battery in it...witch I should of done with mine. loose a lot of weight that way.

 

[ConeHugger01]

@JohnWR IDK if I posted in this or not - installed lightweight AGM battery, saved ~20 pounds, but still in front position, not in trunk. @marksbug Sure lithium-ion is an option. I have to research more to feel comfortable with those in the car, can catch fire easier.
@CaTalyst.X yes, custom wheels. But the hub themselves had rust which I'm sure you know sort of "expands" and the wheels machined to such a tight tolerance, it was too tight of a fit. Without the light rust coating, things fit fine.

 

[ConeHugger01]

2021.08.10 Alignment

Finally got time and some needed tools for the alignment. Long story short, I was given specs from some people and did not 1. look at them carefully enough and make sure I understood them, and 2. the GM caster spec is "misleading" at best, and "downright stupid" at worst. I ended up paying for 2 alignments, which is no big deal as I didn't have to make 2 trips.
Point 1 - Toe in is postive numbers, toe out is negative numbers.
Point 2 - The rear caster pins are 10.5 mm, and in order to measure it you can -
A: buy the really expensive GM rear caster digital tool
B: buy some 10.5mm pins (drill blanks from McMaster-Carr) and a nice piece of 3/4 inch bar stock, and rubber band it all together. Get a magnetic digital angle finder.

VERY IMPORTANT IF YOU DO YOUR OWN ALIGNMENT
But then, the spec for rear caster from GM is "4°" - but careful that's not 4 degrees from perfectly vertical. The index angle to start with is 3.7, so the actual measured vertical angle will be 0.3. See my thread where I asked: Caster adjustment - how much is possible and the post where it's spelled out in long form: #18

Well, live and learn and thankfully I did not drive it with 5.5° of caster. Vote for me for stupid-head of the week!

The specs I finally got (give or take a few hundredths)
Front
camber -2.3
caster 7.0
toe -0.15 (negative is out)

Rear
camber -1.4
caster 0.25
toe 0.05

 

[JohnWR]

.........

VERY IMPORTANT IF YOU DO YOUR OWN ALIGNMENT
But then, the spec for rear caster from GM is "4°" - but careful that's not 4 degrees from perfectly vertical. The index angle to start with is 3.7, so the actual measured vertical angle will be 0.3. See my thread where I asked: Caster adjustment - how much is possible and the post where it's spelled out in long form: #18

...........

Rear
camber -1.4
caster 0.25
toe 0.05

Just to be clear: The actual caster angle is 4 degrees from vertical but the pin holes are 3.7 degrees from vertical so you cannot read the caster directly from them.

 

[kgschlosser]

did you have the alignment tech set the gauge on the alignment rack and check what the reading was to use as an offset. Alignment racks are not always perfectly level.

 

[agent008]

B: buy some 10.5mm pins (drill blanks from McMaster-Carr) and a nice piece of 3/4 inch bar stock, and rubber band it all together. Get a magnetic digital angle finder.

Interesting, wouldn't you have any photos to illustrate this?

 

[JohnWR]

Interesting, wouldn't you have any photos to illustrate this?

There is a picture in this post: Caster adjustment - how much is possible?

 

[ConeHugger01]

2021.11.24

I made this basic leaf catcher thing because I'm missing a bunch of the plastic under tray and leaves would come into the radiator, and even up to the turbo and start to smolder there. I only need it in the fall.