1/4 mile time for a stock 1972 GS350?

Engine torque is no more significant than engine RPM on a drag strip or anywhere else. Each is a but a first order determinant of engine HP, which is what determines DRIVE WHEEL TORQUE and any given wheel speed. That is fact. And I've already laid out the rest for you. Saying that a one car if faster than the other because it makes more torque is no different than making the same statement about engine RPM (e.g, "My car is faster than yours because it redlines at 8,000 RPM instead of 5,000.")

Again, and it's flawless. You have no business discussing the matter unless you fully understand it:

HORSEPOWER and TORQUE

1 HP = 33,000 FT-LB/MIN; 1 circular rotation = 360 degrees = 2 pi radians; 33,000/2 pi radians = 5,252 (derived constant)

HP = TORQUE * RPM/5252 (Horsepower is Torque in motion, with each variable being mathematically linked to the other.)

Per basic algebra, TORQUE = HP*5252/RPM

Hypothetical Tire Diameter for Vehicles 1 and 2 below = 26.4” (Tire Radius = 13.2” = 1.1 feet; Tire circumference =2*Pi* 1.1 feet = 6.91 feet

6.91 Feet = 0.001308712 Mile


Vehicle 1:

Engine: “Torque Monster” 6.0 liter V8 (generic): 300 HP @ 4,000 RPM (Torque @ Peak HP = 394 FT-LB per the above” Torque” equation)

Calculating corresponding overall gear ratio for peak engine HP in 1st gear @ 35 MPH :

35 MPH = 184,800 Feet/Hour = 3,080 Feet/Minute

Velocity = Engine RPM * Tire Circumference/Total Gear Ratio

Total Gear Ratio = (3,080 Feet/Minute * 6.91 Feet)/4,000 RPM = 5.32:1

Drive Axle Torque in 1st gear @ 35 MPH = 394 FT-LB * 5.32 = 2,096 FT-LB

Tractive Force @ the Drive-wheels @ 35 MPH = 2,096 FT-LB/1.1 feet = 1,905 Lbs


Vehicle 2:

Engine: Low torque/high revving 3.0 liter V8 (generic): 300 HP @ 8,000 RPM (Torque @ Peak HP = 197 FT-LB per the above “Torque” equation)

Twice the RPM (8,000 vs. 4,000) permits twice the gear reduction (10.64:1 vs. 5.32:1) while yielding the same top speed of 35 MPH @ peak Horsepower in 1st gear.

Drive Axle Torque in 1st gear @ 35 MPH = 197 FT-LB * 10.64 = 2,096 FT-LB

Tractive Force @ the Drive wheels @ 35 MPH = 2,096 FT-LB/1.1 Feet = 1,905 Lbs


Conclusion: Both engines provide the same tractive force @ the drive-wheels @ 35 MPH in 1st gear. Assuming appropriately specified drivelines and prudent gear selection, a series of tractive force vs. vehicle speed plots would demonstrate that both engines provide comparable tractive force values at all vehicle speeds, thereby equating to comparable accelerative performance. This is attributable to the non-negotiable mathematical relationship between tractive force, engine horsepower across the utilized RPM range, vehicle speed, and the torque multiplier (total gear reduction and tire radius). It is AXLE torque that is the crucial factor in determining vehicle acceleration at any and all vehicles speeds.


Engine torque is no more significant than Engine RPM in determining this, since each is a 1st order determinant of Horsepower and, ultimately, drive axle torque and tractive force at any given vehicle speed.

 

Perhaps this will further clarify things for you.

https://www.flickr.com/photos/141864703@N03/51128423607/in/dateposted-friend/lightbox/

These cars are essentially identical, with the exception of the fact that the higher torque 1991 L98 got its doors blown off by the lower torque 1992 LT1. Note the difference in peak engine HP RPM, though. HP = Torque * RPM/5225. Despite the LT1s peak torque deficit, it's higher revving nature yield a quicker a quicker and faster car from a standing start right on up.

Higher Torque L98: 14.5 second @ 96 MPH quarter mile
Lower torque (but higher RPM) LT1: 13.6 second @ 103 MPH quarter mile

I encourage you to download and view the file in a larger size for viewing purposes.

"My car is faster than yours because its engine makes more torque." LOL

 

Very interesting stuff you posted Bob - I'll have to read through all this a bit more and absorb it (also a M/E but never did much design work).

One place I (might) disagree is your statement on the '70 GS 350. Mine is a very low option car (manual steering/brakes, base straight bench interior, etc.) so should've been around 3500-3550 lb. new, is a 4-sp. & came w/a SCO 3.64 rear. I plan on restoring the car initially to very nearly stock specs only because I'm very curious what it would've run brand new. It was arguably/marginally the quickest factory GS 350 ever made. Based on my experience w/my last '70 GS 350 4-sp. I suspect this one would've run pretty close to 15.0 (+/-) when new.

 

Bob...there is a difference between quicker and faster.
From a street standing start with all things being the same "at idle"... a high torque engine with gobs of low RPM torque such as our big block Buicks, will win a street race over a higher horsepower engine in the same car "at idle". That's what torque does...its quicker not necessarily faster! Torque moves the mass from a predetermined point A to a predetermined point B "quicker" at idle than a car that has more horsepower/rpm capabilities. 99% of races happen on the street and thats where torque shines over RPM horsepower. When people state they have tons of horsepower, i always ask them at what RPM and they most always get this puzzled deer in the headlights look. Their car does not have their stated horsepower all the way across the board from low to high rpm's. So...torque can be more beneficial in street encounters at lower and mid range rpm than higher rpm horsepower. Now...drag racing at the strip is another animal.

 

Torque wins

 

All I know is the big block Buick carries its torque for a mile like 3500-5500 or 4000-6500 rpm, depending on engine specs, how do you beat that with hp.
and stock modified/tuned yer done on that torque on the street

 

Just like I thought Larry has TQ of 550 from 3700 to 5700 how the heck you beat that lol and try and roll race that aany gear your done done.

 

Tough to beat Maxwell House Coffee Can size pistons.....

 

Quote of the Day

 

Thats the issue with math, yeah the numbers may jive on paper and look convincing, but they dont always play out that way in real life. Its black or white with math, no gray areas, it never takes into consideration extenuating circumstances.
I dont know how many times I've told mgmt. I could give a rats ass what your numbers indicate from a formula, ITS NOT REALISTIC

 

You can get those numbers to work right if you know how to set up the Entire equation, you got to add physics to it.
Maybe we can get a graph plotted
Don't we have any other algebra geniuses in here.

looking at Larry's dyno chart you can see the TQ is rocking and with 550 ftlbs from 3700-5700 you might as well say Good Night. It take a 125 shot of nitrous on my 350 to get close to those numbers., and he will still beat me.

The Maxwell House Coffee can car crusher

 

I liken hp and tq to knowledge I learned from owning boats.
My last boat was a 27' Sea Ray Sundancer, it had a single 300 hp 454 MercCruiser, it would do 40/41 mph just me in it.
If I added another 300 hp, the numbers would indicate I'd get 80 mph, just double everything right?
Realistically I'd gain about 10/15 mph, and that gain would be from sheer torque, being able to turn a higher pitched prop.
There would be very little gain if any in actual horsepower, even tho the numbers would show 600 hp,
Both engines produce the same horsepower
But the torque produced is immense compared to the single engine.
Torque is everything.
A buddy of mine had a 32' Maxxum with twin 260 hp 350 MercCruisers, every advance of the throttle, you could feel the torque of the twin engines, you felt a tug on your body.
Another buddy of mine had a 28' Sea Ray with twin 205 hp 4.3 MercCruisers, Big difference in the torque between the V6's and the 350's