Hot Rod Forum banner

LS engine versus SBC throw down, who has the best torque below 3000, HP to HP

67K views 157 replies 14 participants last post by  Project89 
#1 ·
Started this thread to settle the debate of new to old, which engine of similar displacement has the advantage below 3000 rpm with similar HP.

Lets see who can come up with dyno graphs to support their views, I'll start...heres some 500 HP dyno numbers for a SBC.

383 from AFRs website, 195 heads 9.5:1 compression...nice street engine. Everyone has seen this kind of build before...pretty common.

Peak HP=506@6000rpm, torque=520ft/pds@4000rpm

https://www.airflowresearch.com/chevy_dyno.php

Whats important here isn't the peak HP, its the torque under 3000 rpm.

HP/torque=262/454 @3000 rpm

Next on the list is a similar LS3 built up by Crane to showcase their aftermarket cams.

LS3 x 3 – Comparing Three Performance Cams on the Engine Dyno - EngineLabs

Note the 500.9 HP version peaks at 6100 rpm with a peak torque of 488 at 4800 rpm.

More important to note the torque below 3000rpm, 238HP & 418ft/pds @3000.

This is where the SBC really shine folks...under 3000.

Alright who has a dyno sheet for an LS3 that tops that at similar HP, Im looking at you AP72.:thumbup:
 
See less See more
#40 ·
Geez I don't understand you AP, I did not begin looking for an engine for my build with any bias...I came very close to selecting a SBF because in the past thats what I always built. Mustang parts were cheap and plentiful but the weak conrods are what made me select the SBC.

You mentioned its cheaper to build an LS over a SBC, lets use my build for comparison.

10K Rebuilt 0.060" 358ci late model roller block, no heads $250.

"718" GMPP fast burn heads from a circle track crate engine $250

Single plane intake $80

Comp 288HR cam, new in the box $100

Lunati double spring kit, new in the box $250

LS7 lifters, $100

Comp SS roller rockers, new in the box $175

1 5/8" SS headers $125

Finned AL polished Vortec oil pan, $100

Tall cast AL valve covers, new in the box $60

5K kilometers TH400 short tail trans, used $250

I still need a carb, crank trigger ignition, pushrods and a few gaskets.

Whats my investment = $1735?

I looked all over for a used LS and the cheapest 4.8L without drivetrain was $1800 minimum with at least 120 000 kilometers on the clock.

The pricing on EBay was similar, the junkyards yank em as soon as they come in and sell them as long block assys unless they are trash. I counted at least 8 late model vortec blocks in just vans in the yard, pick and pull was $100 each.

Now I don't expect anyone to duplicate the deals I got on components, I was really lucky but it took six months of dedicated daily checks of Kijijji to get these deals shipped from all over Canada.

Thats a complete drivetrain with mostly new components for under $2000 to get close to 500HP.

Every build I see of a 4.8 or 5.3 is soft...way soft under the torque peak compared to even a vortec headed 327. They are great engines and the airflow potential of the heads can support HP on the top end but the open chambers suck for torque...and not a little bit either.

If it wasnt for that issue, I would have built one...but torque is what accelerates the car not HP.
 
#41 ·
torque doesn't do anything, power does... That a whole different ball of wax though- something a LOT of people misunderstand. You can have all the torque in the world and no movement.

As for prices, I don't know if Canada really just has a shortage of parts but around here 5.3L and 4.8L engines go for $500 bucks complete all day long. You don't need a deal of a lifetime, just a truck and a trip to the local wrecking yard. And you don't need to worry about a carb or gaskets, a cam, some springs, and maybe a little extra here or there depending on your tastes (I always touch up the heads and mill a little on my builds but you don't have to).

The $1800 price tag you quoted and mileage is in LS3 price range, not the cheap truck engines.
 
#42 ·
AP thats a great statement about power!
I'll post this for the young and people that don't quite understand

POWER is the measure of how much WORK can be done in a specified TIME. In the example of (power) Work and Energy , a guy pushing the car 165 feet down the street did 16,500 foot-pounds of WORK. If he did that work in two minutes, he would have produced 8250 foot-pounds per minute of POWER (165 feet x 100 pounds ÷ 2 minutes).



HP POWER (or the rate of doing WORK) is dependent on TORQUE and RPM and TIME!!!
TORQUE and RPM are the MEASURED quantities of engine output.
POWER is CALCULATED from torque and RPM

The definition of one horsepower is 33,000 foot-pounds per minute.

HP = Torque x RPM ÷ 5252
TORQUE = HP x 5252 ÷ RPM

A unit of work is FT. per LB (Ft. LBs.), a unit of torque is Lbs. per foot (Lbs Ft) , ( even though most people in this country reverse it and state torque as FT. LBs)

POWER is the measure of how much WORK can be done in a specified TIME
An engine fly wheel dynamometer measures torque and rpm, but a chassis dynamometer measures force and speed.
power Formula for engine Dyno is:
HP = torque (Lb Ft) x rpm x 2 x pi / 33000 = torque (Lb Ft) x rpm / 5252.113122... (without allowing for any drive train drag! or power scavengers! (Like an Alternator))

power Formula for Chasis Dyno is:
HP = force (lb) x speed (mph) / 375 (with drag from drive train and savaging devices installed)

Jester LOL :D:evil:
 
#43 ·
In simpler terms acceleration is dependent on the power applied, you can have a astronomical torque value but if it's applied at a low rate (giving you low power) you'll have slow acceleration, if you have astronomical power but bet low torque you'll still be snapping your neck under acceleration.

Some people go after power with low rpm and high torque, some go with high rpm and low torque, if the power is the same how you get it is irrelevant.
 
#44 ·
...and that is exactly what a dyno chart is an indicator of...power. More specifically area under the curve. You can measure it with software or manually if you enjoy the abuse but it is the basis of how power is measured.

Now that we understand the concept of power and how it is measured, explain to me how any engine that has identical peak HorsePower figures but has less area under the dyno curve makes more power?

This was the entire point of this exercise.:confused:
 
#48 ·
Funny thing about opinions is that they're irrelevant here.

And the weight of the engine parts and everything else doesn't matter if you measure the power at the wheels. An engine dyno measures it at the back of the flywheel, so again it doesn't matter what the components weigh when you measure it there, it's net of the parasitic losses.

This really isn't rocket science, stop trying to confuse yourselves.
 
#51 · (Edited)
That's why I said you made a bad comparison using acceleration as an example of power between differently built engines!And by the way some engine dynos have the water pumps and fans on the engines and some use external water pumps or electrics! and many factors can change power readings on a chassis dyno all the way from A to Z including tires ! Tires will grow as wheel speed increases and the rubber heats up. Different tires have different coefficients of friction, which could impact the amount of slippage on the rollers. Tire changes affect an inertia dyno most, as it changes the effective rotational mass and overall gear ratio. "Going to a smaller-od tire is like increasing gear ratio; you lose horsepower." !!!!!! So a chasis Dyno doesn't measure engine power only power put to the ground on that particular car and then pic a loss % anywhere from 12% as some use on the LS engines to the 30% that's closer to reality that we used on the old small block and then use softwear to smooth the graph as they do in this age!

And no its not rocket science! Its Physics and Automotive engineering and mechanical sciences LOL! If anyone really wants to understand why they come on here to ask us whats best and whats better! The trouble comes from people who were raised in the computer age that just looks it up and a table or chart does it for them! And this whole thread is opinions on whats best and cheapest and what puts out more power or there wouldn't be a thread !!!! But I guess yours is the only opinion on here that counts LOL:D The title of this thread is "LS engine versus SBC throw down, who has the best torque below 3000, HP to HP" that makes it open for debate and opinions on data!!!!

Jester
 
#49 ·
Relax Ap72,Im going to switch horses here as you are failing miserably.
All your answers are:
does no!
does to!
Thats not relevent!

Chris I challenge you to this debate,because:
If I lose,no shame to me,
You know a lot more than I do so Im here to learn,
Giving you a run and really getting the best out of you will probably have a lot of people in awe,,,

I have to spend a little time with the bitter 1/2, then the gloves are on,,,
have fun with this
 
#50 ·
If I disappear I will come back later;
Opening friendly statement.
LS series is better because:
GM sells those engines,although in a mild form,pretty much how I would build an engine, ie
roller cam from the factory,had to buy one for my car
high ratio rocker shafts,exactly what I want for high RPM stability(have those on my gen 1 too)
finally a decent fuel injection system,until the later LSs came out the factory F.I. was a joke
Cylinder casting that flow better than the improved 1953/54 original design
aluminum heads are common now,but not in the 70s
improved deck height,rod length for larger engines,original design was great for a 265.
6 bolt blocks could retain a rogue crank,though not many try to escape SBCs
 
#53 ·
The LS design is light years ahead of anything that came on a small blocks I'm amazed every time I open one up:thumbup:

I build and have built both for many years on the small block and a lot fewer years on the LS design! and have my favorite! I know the small block is cheaper because I can build them for less !!! And produce comparable power for less (Not stock), an LS here at a yard is around $900 or more running with a 30 day guarantee not to smoke!! A small block 1 or 2, I can get for $300 or a little more with the same 30 day! To overhaul the LS it takes around 38 hours for a usual rebuild! The small block is 19 hrs. for a stock blue print! Most garages can do a standard rebuild in 15 hrs on a small block! the price of the good coils alone LOL! It only takes one for the small block!! The piston slap in the LSs is a problem with the bore wear ( have seen Many)! Worrying about getting a cracked head that they were plagued with because so many were produced by different co's for GM, LS head bolts are not re-usable, if you are on a tight budget you can squeeze plenty of power out of several stock type LS heads! but for the parts money differences and price of the used engine differences you can get good heads for the small block or get good cast heads and rework them!
The Ls cam kit I installed last with medium lift Cam specs: 219/228 .525"/.525" 112 LSA roller was over $500 and that was a deal, a small block flat tappet cam kit Duration 276/276, Lift .533/.533, $140! another good deal!
I can go on.

And the dyno curves are evident in my opinion especially when the 350 small block HP was under stated at the time 60s to the 70s like the LT1 factory rated at 370 bhp (the NHRA rated it at 425 hp) 370 was Because of the insurance lobby, then the SB around 74 had its power actually diminished and now the new engines HP ratings are questionable (In my opinion LOL)

Jester
 
#56 ·
Modern power measurements have never been more "accurate", it was hit or miss before 2006.

Why not compare the GEN 1/2 and the GEN 3 Hotcam kits against one another, instead of a GEN 3 Hotcam kit using a roller cam, vs. a flat tappet cam? I would never suggest a flat tappet cam these days.

There was no bone stock LT1 engine outputting 425hp, no matter what the NHRA was feeding people.

peace
Hog
 
#57 · (Edited)
Prior to 1972, American car makers used the SAE (Society of Automotive Engineers) “gross” measurement of horsepower. Gross meant the figure was taken from an engine running on a dyno, with no air cleaner assembly, accessories or exhaust system connected.

By 1971, car makers began reducing compression in many engines in order to meet upcoming emissions requirements and to use unleaded fuel. General Motors and Chrysler began advertising both gross and SAE net figures in 1971, derived from an engine tested with air cleaner assembly, accessories or exhaust system connected.

The net ratings, which were applied across the board for 1972, must have been a shock to some customers. Suddenly, muscle cars appeared to lose 100 hp or more.For example, the Corvette’s optional LT-1 350 cu. in. small block V-8 had 370 gross hp in 1970 (with 11:1 compression), then a 330 hp gross rating (with 9:1 compression) for 1971-1972 with a 255 hp net rating. The mighty Chrysler 426 cu. in. Hemi kept its high compression and 425 hp gross rating for 1971 and showed 350 net hp.
Quote "People were stunned to see that an LS6 Chevelle SS, with 450-hp rating, put down 288 rear wheel hp in the dyno test. That would have put a net hp rating at around 350 hp for that big block." Quote HEMMINGS

Jester OUCH!!

Quote “Rear wheel horsepower was at least 30 percent lower than the reported gross figure, in some cases even more,”Quote HAGERTY (But now tests are done with a 12 to 15% figure)

Keep in mind that some muscle cars came specially prepped from press fleets and testing, sometimes with non-factory super tunes. That’s one reason that making comparisons using vintage Dyno & road tests from the factory can be different. Different axle ratios, testing methods, drivers, test conditions and other variables also affect results. NHRA ratings like the 1970 LT1 were done with cars that weren't modified' ( just Supertuned ) for the track And rated at 425 HP! NHRA didn't test cars off the show room floor LOL The factory did that!And any team running stock class super tuned their cars ( to max out performance of stock parts and settings like Timing, plug heat ranges, lighter visc. oil, Tire sizes, Carb jetting, loose lifter settings ETC 'ETC Same as we do on our Dyno tests on Muscle cars to get max performance While on a Dyno!!!!!

Don't tell me you guys put a car on a dyno and don't change the tune of the engine to make it better or do you get your 3 runs and just leave it alone get your graph and HP readings and leave:drunk::confused:! LOL

Quote "You don’t need a dynamometer to estimate net horsepower for classic muscle cars, or to check claims of current models. Roger Huntington, the renowned technical writer who penned articles for many car magazines into the 1980s, developed a formula to show the relationship between quarter-mile performance and power output. Others have refined those formulas and developed calculators, in which you can use performance figures and vehicle weight to get estimated hp. (To check hp figures for this article, we used calculators at http://www.stealth316.com/2-calc-hp-et-mph.htm.)" Quote

444 HP
QUOTE "Ford rates the modern BOSS with its DOHC 5.0-liter V-8 at 444 hp. Car & Driver, driving one the way most drivers would (not powershifting), recorded a 12.8-sec. ET at 113 mph. But Muscle "Mustangs & Fast Fords", with hot shoe Evan Smith banging off full-throttle powershifts and the car running on drag radials, scorched the quarter-mile in just 12.07 sec. at 114 mph." Those mph figures and the formula for figuring out HP from drag strip times gives you Different HP readings on the same car!!!!

The L72 tested to 450 hp at 6,400 rpm , but was changed to a rating of in the books and on record to 425 hp at 5,600 rpm at a point Lower on the rpm curve, these gross ratings were purely a fiction to satisfy insurance companies and the safety lobby!! That's why the early engines 427 FORD, 427 CHEVY, 426 HEMI, ETC ETC all came in at 425 HP in the books even though they made much more HP higher in the rpm curve!!!!

QUOTE "racing officials frequently “factored” underrated engines for the purposes of classification; Chrysler’s very strong 340 cu. in. (5,567 cc) engine, for example, carried a conservative 275 hp (205 kW) rating from the factory, but the NHRA treated it as a 325 hp (242 kW) engine for racing purposes." Quote

I Dynoed and helped crews tune these old engines at the time these factory ratings were present and from actual experience saw that these engines were under rated and produced much more HP at Higher RPMs then was advertized!!!! The 426 425 HP Hemi ran between 450 and 525hp on the dynos from engine to engine !!!! And the early LT1 was hovering around 400 some less some more! I know and others know but to convince anyone that refuses to except that is a like trying to tell someone that the Bible isn't all factual And if Snake bit enough times you DIE!!

I'll Continue later :D LOL my typing finger has a blister :pain:

Jes:pain:er OUCH!
 
#60 ·
There's no "my definition" simply the correct one. If you were closer I'd give you my old text books that get into what it is but wiki does a decent job of defining it. There's also various educational sites that explain it. Google it. So much information is just a click away.
 
#62 · (Edited)
:thumbup:This don't count but its cool!!!:mwink: A Mopar Mouse:evil: Now we need a FORD Mouse 4 Jaw Chuck ?

Jester :thumbup:

Shady Dell Speed Shop 428″ Small Block Chrysler on the dyno @ Shady Dell. 11.3:1 compression, pump gas, 4.125″ bore R3 block, 4.0″ SCAT Crank, SDSS Street Port W9 heads 2.15″/1.60″ valves, “772″ MP intake manifold, 1050 Pro Systems Dominator, 272/276 @ .050″ .726″ lift, 110 LSA street solid roller, 1.6 T&D rocker. 748 HP @ 6900 RPM, 610 FT LB TQ @ 5600 RPM.

 
#66 · (Edited)
I being a mopar GUY :mwink: It makes my heart pound LOL

Jester:thumbup:

Here's a FORD :small block Ford engine built by CNC Motorsports. This engine measures out to 438ci and with the nitrous bottle valve open, makes 1,270hp and over 1,000 lb/ft of torque on the dyno. Peak hp comes at 6,900 RPM while peak torque comes at 6,000. The guys spun the mill up to 8,300 during the dyno pull shown here.

 
#69 ·
Nope, that idea won't work either. Adding power at various rpm points is just some silly idea you came up with, it doesn't mean anything. Btw rotational acceleration is held constant on most dynos. 400 rpm/s or 600rpm/s are the two commonly used rates.

Also an example of an engine that makes no torque but makes power- a jet engine. Those have moved some cars pretty damn quickly.
 
#79 ·
Nice writeup previously.

Just a question, do you consider manifolds to headers a mod, or a part of tuning? Lots of the old iron had crap parts installed simply because they new racers would be installing headers and exhaust. Remember the BBC Camaro exhaust? ZL1 engine power was cut down to 275hp through the manifolds and stock exhaust.

To reference an earlier question.
There are some people that simply do their 3 runs, and some who actually make tuning changes.


BTW Jet A fuel is a kerosene based fuel
While Jet B is Naptha based (30% kerosene and 70% gasoline-widecut)


The Jet cars smell awesome when standing a ways begind them. Thats was an experience.

peace
Hog
 
#77 ·
I said to multiply the torque value to the rpm value to give the advantage to a motor that made its power higher in the rpm range, normally we just add the values.

Ok so we cant compare the LS motor to the SBC, lets compare other identical CI engines to see who wins.

Ill take a 434 SBC against a 427 BBC for fun, not directly comparable because the blocks weights are not the same but lets do it. I think we should look at a 440 Dodge as well, those are great engines too.

These are excellent comparisons.
 
This is an older thread, you may not receive a response, and could be reviving an old thread. Please consider creating a new thread.
Top