geerookie

I just picked up my new scales and couldn't wait to test them
Believe it or not I was able to remove another 84lbs.
The weight below is without me and about 4 gallons of gas.

Well, I have removed just about everything I can afford to remove. I have some pictures of what she looks like, now that I'm basically done removing weight. I will post them up tomorrow.

The weight distribution feels funny right now. The car feels lighter and with a 54.2% - 45.8% bias right now it spins the rear tires in 3rd gear without even really trying. That's on the street and really no heat in the tires.
I will be loading her up on the trailer and taking her down to get the full cage w/ NASCAR door bars installed in the next week or so. Then when I get her back I will install the trans cooler and rear diff cooler. I'm guessing with the cage and coolers I will be adding back about 200lbs.
I'm aiming for a competition weight of 2955#'s and it looks like I will be able to make it. This will allow me to run about 349 RWHP in ST2. My tired old LS1 should have no problem with that number.
I just need to find someone to tune it properly and conservatively so she will last another season.



Removed:
BCM computer and all related wiring and circuits
fog lights, brackets relays and wires
AC Compressor, AC Condenser
AC Compressor bracket and all bolt and relays
Headlights, motors, brackets, bolts and associated wiring and relays
Factory fans and shroud including unneeded relays
windshield washer tank, motor and all hoses including the ones on the wipers
All hood release related cables, brackets, handles and hardware
battery and battery box (15lb battery relocated behind pass. seat on floor)
Air bags and air bag controller
Dash Pad
All inside vents, ducts, mounting tabs and hardware
The column lock motor and assembly
Wiper control stalk (plus it's embarrassing when you hit it accidentally on the track)
Any and ALL interior panels, carpet, covers, mounting tabs, brackets etc.
Door control modules, all relays and wiring associated with them
Door opening handles, locks and rods
Seat belts, brackets, bolts etc.
YAW sensor and Lateral Accelerometer
All stereo stuff, mounts, brackets and wiring
All E-brake hardware, mounts, cables in the car, under the car and on the rear wheels including the dust shields
All the gas door release cables, solenoid, relays and buttons
All wiring inside the rear of the car and related relays
Cut out the wheel well thing in the back flush with the frame and put a flat piece of aluminum in the hole. This saved weight but more importantly I can remove the rear-end without having to drop the rear cradle, which is helpful when you don't have a lift!
scraped out every last bit of sound deadening material
removed all interior lights and wiring
Heater/AC blower motor assembly and all wiring, relays etc.
Heat exchanger assembly and all water in it and all hoses from water pump etc.
HVAC controls and all wiring
side window glass, motors, wiring and relays and switches
door bars and excess fiberglass on door interior
AIR system and Catalytic converters
Rear hatch glass and replace with lexan
rear hatch release solenoids, wiring, mounting brackets and relays

Still to Remove this winter:
Crash foam in the front and rear bumpers
Radiator over flow tank on right front fender
5th and 6th countershaft, gears and synchros etc.

Rear hatch area cut out ready for cage install. Then after the cage install I will mount pumps for coolers on the pass side frame rail and then a thin aluminum plate over the top with 1/4 turn fastners for easy removal and access to the rearend and tranny.


Passenger side before the major removal work began.


After all the extra wiring and the BCM computer, HVAC etc. is removed


Drivers area, notice no turn signal stalk, wiper stalk, HUD or key. The switch under the gauges is the 2 speed wipers with auto hide still working



Doors...still have the power mirrors working.


This is the modified door latch. Notice the door bar is completely removed, 6lbs and the lock mechanism, power door lock motor and the linkage rods are gone. 1/16" stainless cable is the inside release.

jasonberkeley

Don't remove the crash foam. They each way less that a pound and absorb alot of energy. take it from someone who has used them!

drivinhard

yeah you get to a point where it's as light as elbow grease allows, then you gotta reach for the wallet to get lighter

My car is headed to the cage shop right after Dec RA, so it's getting cage prep'd/gutted right now. I'll weigh it before the ballast (a lot of it) goes in. I will have to run nearly full tanks + ballast to make weight, but it's going to be balanced nicely

flink

Aero drag. The car which is 10% heavier and 10% more powerful will pass you in the straights

A 295.5 lb ST2 vette with a 34.9 hp engine will do well in the turns, but it has a top speed of 50 mph.

geerookie

I don't understand your math...could you explain?

geerookie

Thanks for the tip. I was wondering about the weight and wasn't looking forward to the extra work.

Are you sure about the weight?

geerookie

Are you installing a 6 point or 8 point cage?
Who's doing it? What's the cost?

sperkins

Man that RR is screaming for some ballast.

drivinhard

maybe, assuming same exit speed. i would give the nod to the lighter car on exit speed. after that, it's hard to chase down momentum in a limited distance. give the nod to the lighter car at the next braking zone to.

drivinhard

std 6 pt (A pillar, main hoop, 2 dog legs (tied in by a cross bar). 2 more "attachment" pts for the NASCAR bars.

I think genesis one auto is in the $2.5k range for such. BJ is a fantastic fabricator, he was working on a custom sheetmetal dash for a resto-mod muscle car last time i was there, some of the pieces he was making I couldn't make if you left me in that shop working on it and I lived to be Methuselah's age

geerookie

That's what physics and the math tell me. Given the same power to weight the cars should accelerate the same
The lighter car will corner faster (assuming similar CG), be able to brake later and decelerate faster.

geerookie

I'm going to mount the pumps for the rear-end and trans-cooler on that side for sure!
The coolers will be towards that side also.

L98Terror

But it's not the same hp/lb in ST2 the heavier the car you get a HP bonus the lighter a HP penalty. I'm not sure where that sweet spot is, wish I had that answer.

drivinhard

because they are only looking at a peak hp number, torque is "free" and you can "hold" a motor to a certain hp level (and keep the area under the curve the same), I say lighter is still probably "better" since the torque/weight ratio should stay nearly the same. the car will pull the hardest at the torque peak, not the hp peak.

IMHO this is why it's a cool system, there is a lot of head scratching that (can) go into it

wallyman424

I dont understand why people seem to dismiss HP as a measurement of speed/pulling ability.

HP is a function of torque and RPM. Torque by itself is useless. You can have a million pounds of torque, and if it only exists from 1000-1200 rpm, you're screwed. What you want is a dyno graph where your HP maxes out as early as possible, and continues along at that level to redline. Its somewhat attainable w/ a NA car, but super super easy to do with a turbo car.

geerookie

Deceleration and average speed through a corner or down a straight make the most difference in laps times, not acceleration. If you exit a corner 15mph faster than the big HP car but have 10 - 15 mph less top speed but can carry that lower top speed further into the next corner you will have lower lap times on almost every track. Not to mention passing will be easier at the end of straights and in corners
Deceleration is "free" in NASA/ST racing. It's also cheaper than horsepower and easier to attain big numbers.
Yes you pay a HP penalty for a lighter car BUT a lighter car decelerates quicker, uses up less brakes therefore more consistent over time, can carry more speed through a corner on smaller tires.
ST gives you a HP bonus if you use a 275 tire

Just a quick story:
This season a friend of mine who doesn't race but has a well setup C5 was suprised by my car on a Friday open track day.
He has coilovers, T1 sways and about 650HP and about 3300lbs. He runs 315's on the front and 345's on the rear. Obviously, he wouldn't qualify for ST2.
We have a lot of fun running together and I can usually beat him in the corners or under braking and he kills me on the straights. When running apart or on open track we have very close lap times at all tracks. Sometimes I'm a little faster and sometimes he's faster.
Times at the Glen 2:12:xx, Pocono North 0:58:xx, Limerock 0:59:xx just to give you an idea.
We aren't the fastest but we are nowhere near the back of the pack.
I have a light car, 310 RWHP (stock LS1 w/ 114k miles), coilovers, stock front sway and no rear sway and run 275 tires all around.

When I unloaded my car on Friday at NJMP THunderbolt a fellow racer wanted to try a "lighter" Corvette so I let him drive my car for a few of the open sessions on Friday. This kid can drive, holds a few of the track records for the NE in ST1/ST2. After the first session my friend in the 650HP car came over to my pit and said, "What have you done to that car? It flys around the track! I couldn't keep up with you at all."
I smiled and told him I hadn't changed a thing on the car Of course he called on that and I told him, Really, I haven't changed a thing on the car, just a slight change in the car...... I wasn't driving.
The point is, I'm pretty sure a lighter car driven well will beat a high horsepower car driven well every time assuming the same power to weight ratio.
Just to give you an idea of times, my friend and I run about 1:29:xx at NJMP Thunderbolt and the guy driving my car was running 1:26:xx.
The guy driving my car drives a "high" HP/heavy C6 Corvette with T1 suspension, 315's and 345's in ST2. He said he was taking it easy in my car since he wasn't familiar with it yet but felt he had another second or so to be gained. In his car he runs flat out, a low 1:27:xx on a regular basis at this track. He said my car was easier to control, much more predictable and was easy to "throw" around.

This was just an example that makes me think I'm headed in the right direction with my car for ST2.

Falcon

Couldn't gearing be used at that point to take advantage of the monstrous torque?

geerookie

A million ft/lb of torque from 1k - 1.2k = a 36 speed gear box

HP is the WORK being DONE! Technically, torque is the potential to do work....I think that's stated correctly?

Two really small turbos on an LS1 Just need to find someone who can tune it properly.

drivinhard

I’m not dismissing hp as an important factor. Torque/hp must include gearing in the conversation. No I don’t short shift the car, even though the torque peak is falling off, the car is still going to pull harder making 275 ft/lb of torque in 2nd gear than it will make 325 ft/lb in 3rd gear, because of the torque multiplication of the shorter gear. So tach it out. But it’s not a theory that the car will pull max accel G’s at the torque peak of the motor, in that given gear, assuming 100% traction. Torque is the only directly measured figure, hp is just torque’s relation to RPM

In a nutshell I’m simply saying:

Taking an LS1/LS6 and putting a ceiling on the peak hp number only affects a narrow part of the entire powerband. Road course operation of 3000-5800 (give or take) won’t look a bit different. 5800+ to redline will be somewhat reduced. Like wally said, get to max hp as fast as possible

During a lap around X race track, you are only WOT for a small % of the lap

During that portion of time you are WOT, you are only operating in the hp peak for an even smaller % of that time

Reducing the mass of the car affects the performance of the car 100% of the lap

There is a sweet spot, I don’t claim to know what it is

I think greg’s ST2 idea is a cool idea. He’s got a tired stock LS1 that can’t make that much power anyway, so get the car as light as he can, and see what it does. 275’s would work well on a light car, so with a .4 bump, he really wouldn’t even be falling that much off the hp/weight of the bigger/more powerful cars

wallyman424

its not the tuning that bothers me as much as how to facilitate cooling. I dont think the front of a vette has enough surface area to deal w/ an intercooler, radiator, oil cooler and trans cooler (in my case).

Drivinhard, that is the beauty of st2. You can stick with whatever junky motor you have (like I have for the past 5 years) and just modify the car around it to make it competitive.