Rij1

I'm trying to figure out how much hp/torque i'm getting rite now and need to know the weight of the car. 1994 z28 t top m6, also the trans gear ratio for each gear.

jproz1167

Take it to a truck stop and weigh it.

jit11375

3436 for the weight iirc

JakeRobb

My 2002 T-top Z28 M6 weighed 3546 with me in the car, helmet on, and a quarter tank of gas. Floor mats, spare, etc all still in the car. Yours would be a bit heavier (LT1's iron block vs. LS1's aluminum block). For racing calculations, the most useful number will be actual race weight. If you're going to pull the spare when you go racing, pull the spare when you weigh the car.

As for gear ratios:

1st: 2.66:1
2nd: 1.78
3rd: 1.30
4th: 1.00
5th: 0.74
6th: 0.60
Reverse: 2.90

dennis5374

Funny I've been told that the 98-02 fbodys were heavier. Maybe I was misinformed. Ill look into it and post back here in a little bit

dennis5374

Seems the 98 weighs in at 3400 . My cars title states 3340. Im also a hard top if that matters but im nowhere near that weight anymore. Hoping for some low 10's high 9's next spring.

LT1 POWR

Mine weighs 3400 without me or any HVAC or ABS stuff. But I also have a higher capacity oil pan, tranny pan, radiator and diff cover for the heavier 12 bolt, and a turbo that adds probably 50-70lbs as well as heavier/stronger suspension components.

When it was mostly stock, with no rear seats, no spare and no passenger seat, it weighed 3300 for comparison. All these weights are without me of course. I'd love top get it down to 3000lbs, but I'm not gutting the interior, so it looks like 3300-3400 is the lowest I'll be getting.

Injuneer

Not exactly "Advanced Tech", but go to the bottom of this page:

http://www.f-body.org/tech/tech.htm#FourthGen


6th gear in a 94-02 T56 is 0.50:1

Rij1

Sorry about that I Suppose I should have put this post in the suspension catagory, So what is the common persentage of HP loss to the wheels from the engine on the 4th gen's.
That's good info Injuneer
http://www.f-body.org/tech/tech.htm#FourthGen

Injuneer

I ran comparison tests on my engine, running it on an engine dyno with full intake and exhaust to get flywheel HP, and they running the car on a chassis dyno to get rwHP.

The results vary with HP input, due to the fact that there is a fixed component (mass of rotating parts) and a variable component (friction in gears and bearings varies with load).

=========
T56
McLeod Street Twin with Steel flywheel
3" chrome moly driveshaft
Strange 12-bolt w/ 3.73 gears
17x11.0" ZR1 wheels w/ 315/35-17 BFG Drag Radials:

N/A
425 rwHP / 486 flywheel HP = 12.6% loss

N2O
557 rwHP / 635 flywheel HP = 12.3% loss
671 rwHP / 763 flywheel HP = 12.1% loss
============

TH400
~3,800 RPM non-locking converter (5,000RPM flash stall @ 800 lb-ft)
3" chrome moly driveshaft
Strange 12-bolt w/ 4.11 gears
17x11.0" ZR1 wheels w/ 315/35-17 BFG Drag Radials:

N/A
390 rwHP / 486 flywheel HP = 19.8% loss

N2O
507 rwHP / 635 flywheel HP = 20.2% loss
602 rwHP / 763 flywheel HP = 21.1% loss

There you see the effect of converter slip with increasing load, and the exponential nature of the pumping losses.
===============

The T56 numbers are all consistent. By the time the TH400 was installed, there may have been minor changes that affected engine flywheel HP, but we just assumed they were negligible.


For a 400-500 flywheel HP M6 setup, I would assume 12.5 - 13% max loss.

For a 400-500 flywheel HP 4L60E setup, I'm guessing about 16 to 17% loss. I have not tested a 4L60E.

For a beefed up 3 speed auto, with a high stall converter, it can run anywhere from 19-25+%.

The rear axle is a major contributor to driveline loss. The published numbers I have seen are:

Dana 60: 5% loss

10-bolt/12-bolt: 7% loss

9-inch: 10% loss

96capricemgr

Just to be clear the way Injuneer had his tested with complete intake and exhaust as it would see in the car is VERY non-typical, he went the extra mile.

The vast majority of engine dyno to rwhp tests will show greater losses because the engine tests are done with dyno headers that don't have to clear a chassis and no exhaust system to speak of, are done without a mechanical WP, alternator or PS to spin, are done without any intake tract.

Golen is the largest source of flywheel HP numbers we have for an LT1 and in 4L60E cars with his engines the losses generally total up to 25%. I covered a lot of additional losses above but another contributing factor is likely his LandAirSea dyno which if you google you will find their chassis dyno especially puts out extremely inflated numbers. Less info on the engine dyno but if they setup the chassis version to inflate numbers why expect anything else from their engine dyno.

Have seen a number of 440hp Golen strokers put down 325-335 a 25% loss would be 330rwhp. Those were mostly in b-bodies with 4L60E 9.5" converter and 8.5" 10-bolt.

Far as weight, measure it. Most estimates I have seen guys give overinflate the weight of their cars. I have seen guys report heavier weights for cars stripped of exhaust systems/AC/power seats, swaybars etc with skinnies, than what I MEASURE mine to weight with all that intact plus street tires on the front. Some of it is flat out dishonesty, sometimes it is just estimates based on bad info.