swathdiver
Full Access Member
Timeslips like that tell me that the motor is plenty healthy! If your race weight was 5,900 pounds, she was putting down 325 rear wheel horsepower!
@badandyturbo
Growing up doesn't have to suck
- Thread starter iamdub
- Start date
Disclaimer: Links on this page pointing to Amazon, eBay and other sites may include affiliate code. If you click them and make a purchase, we may earn a small commission.
Timeslips like that tell me that the motor is plenty healthy! If your race weight was 5,900 pounds, she was putting down 325 rear wheel horsepower!
@badandyturbo
OP
OP
iamdub
Full Access Member
I believe it's plenty healthy, but no way is it 325 at the wheels ...yet!
I thought it was rated at/around 325 at the crank. I've always calculated an 18% loss through the 4L60/65, which should be 266 at the wheels. My data shows the curb weight to be 5,234. I'm 190lbs and I had about 10 gallons (of 89 octane) in the tank, so I'll call that 60lbs. No third row seats so I'll subtract 100lbs, bringing my race weight to 5,384.
5,384 and 15.656 calculates to 277.3 at the wheels.
Calculating HP from MPH and weight comes to 293.
The average of 293 and 277 is 285. So, 5,384lbs moved by 285 horses comes to an E.T. of 15.51 @ 87.2.
Buuuuut... I think GM rates their engines with all the accessories installed and loaded, so that skews it further.
So, now that I know it's plenty healthy, I'm gonna pull it out and tear it to pieces. lol
swathdiver
Full Access Member
Ok, I'm within a horse. Did you come up with the curb weight by subtracting the cargo weight from the GVWR?
OP
OP
iamdub
Full Access Member
No, I got it from a website that supposedly is copied from GM spec documents. It seemed legit:
https://www.automobile-catalog.com/car/2008/1203275/chevrolet_tahoe_ltz_2wd_5_3l_v-8.html
OP
OP
iamdub
Full Access Member
Had a few hours to work on it today. First, I did some quick testing on the Air lift bags. I measured the amount of lift at certain air pressures, from floor to fender-
0psi: 33 3/8"
5psi: 33 1/2"
35psi: 34 1/4"
I tested both bags at the same time since one side would affect the other approximately 50% (tested and confirmed this). My Tahoe sits level, within 1/16" left-to-right so these measurements apply to both sides (also tested and confirmed).
Then I moved on to motor stuff-
I unbolted the torque converter from the flexplate to see if the odd heavy vibe I felt at a very narrow RPM range would change any. It didn't, so I'm gonna assume/hope it's an issue with the crank pulley/balancer and replace it when I reassemble the motor.
How I turn those bolts:
...And hold the crank:
I removed the spark plugs while the motor was still hot in attempt to run a compression test. By the time I got the wires off and spark plugs out, the motor had cooled considerably. I decided I'd just test it cold on the stand once I had it out and moved on to other things.
Didn't break the tube! This rarely happens:
So far, I have the hood off, exhaust manifolds unbolted and air intake removed:
I really hope I don't have any late days with work. I wanna get the heads off to get them to the machine shop ASAP.
0psi: 33 3/8"
5psi: 33 1/2"
35psi: 34 1/4"
I tested both bags at the same time since one side would affect the other approximately 50% (tested and confirmed this). My Tahoe sits level, within 1/16" left-to-right so these measurements apply to both sides (also tested and confirmed).
Then I moved on to motor stuff-
I unbolted the torque converter from the flexplate to see if the odd heavy vibe I felt at a very narrow RPM range would change any. It didn't, so I'm gonna assume/hope it's an issue with the crank pulley/balancer and replace it when I reassemble the motor.
How I turn those bolts:
...And hold the crank:
I removed the spark plugs while the motor was still hot in attempt to run a compression test. By the time I got the wires off and spark plugs out, the motor had cooled considerably. I decided I'd just test it cold on the stand once I had it out and moved on to other things.
Didn't break the tube! This rarely happens:
So far, I have the hood off, exhaust manifolds unbolted and air intake removed:
I really hope I don't have any late days with work. I wanna get the heads off to get them to the machine shop ASAP.
swathdiver
Full Access Member
Ok, well next time your in the shop get a little more precise by doing it the other way.
Tonyrodz
Resident Resident
How were your exhaust manifold bolts? None were broken?
OP
OP
iamdub
Full Access Member
I'll check the door tag, but I must be misunderstanding you somewhere or I missed something.
OP
OP
iamdub
Full Access Member
Nope. I've never had any broken ones, but I was expecting to break some when trying to back them out. All came right out with the Central Pneumatic 1/2" air ratchet. I might have had to crack a few loose with it before squeezing the trigger, but it was all one hand stuff.
OP
OP
iamdub
Full Access Member
As of last night:
Battery disconnected
Oil and coolant drained
Belts removed
Fans removed
Harness completely unplugged
Intake manifold removed
Water pump removed
Alternator removed
Accessory bracket and power steering pump unbolted and moved to side
Starter removed
It'll be ready to come out after the A/C compressor/bracket, mounts and bellhousing are unbolted. I'm gonna see if I can get the top four bellhousing bolts with the heads in place and not through the bottom with all the ratchet extension acrobatics. If it takes too long, I'm pulling the heads. Tonight's goal is to have it on the stand and maybe running the compression test.
Battery disconnected
Oil and coolant drained
Belts removed
Fans removed
Harness completely unplugged
Intake manifold removed
Water pump removed
Alternator removed
Accessory bracket and power steering pump unbolted and moved to side
Starter removed
It'll be ready to come out after the A/C compressor/bracket, mounts and bellhousing are unbolted. I'm gonna see if I can get the top four bellhousing bolts with the heads in place and not through the bottom with all the ratchet extension acrobatics. If it takes too long, I'm pulling the heads. Tonight's goal is to have it on the stand and maybe running the compression test.
