Old versus new engines

[chevynut]

There seems to be a lot of differing opinions about engine technology from the early days of the Chevy V8s to the latest high tech supercharged engines. I

I thought I'd start a thread to compare these engines and discuss some of the great performing engines of the 60's. Obviously the horsepower race of the 60's has again been ignited, with the Camaro and Corvette both featuring engines near the 650 HP mark.

Some of this has been going on off-topic on another thread, and I want to bring that discussion here. What are your favorite engines today, and in the late 60's? How do they compare over a span of 50 years? Did technology really change that much?

[chevynut]

I'll start this off with a good article I found, comparing the '70 LT-1 to the 90's LT1.

http://www.superchevy.com/how-to/vemp-1008-1970-gm-350-small-block-engine/

"Run on the engine dyno, the LT1 produced 350 hp at 5,700 rpm and 379 lb-ft of torque eat 3,800 rpm. This compares favorably with the factory rating of 300 hp and 340 lb-ft. Torque production exceeded 350 lb-ft from 2,600 rpm to 5,100 rpm, while the horsepower curve flattened out past 5,000 rpm. Despite a factory (gross) rating of 370 hp, the LT-1 produced almost exactly the same peak power as the LT1, with a peak of 353 hp at 5,600 rpm. In the torque department, the '70 LT-1 offered 292 lb-ft at 4,100 rpm, bettering the LT1 by as much as 13 lb-ft. Torque production from the LT-1 exceeded 350 lb-ft all the way up to 5,300 rpm, but like the LT1, power output from the LT-1 fell flat past 5,000 rpm. Given the wilder cam timing, this seems unusual, but it's hard to argue with the results of direct, back-to-back testing. Despite the sizable differences in rated output and more than 20 years of technology, the two LT small-blocks are more alike than different, at least in terms of power production. From the results of this test, it's obvious that the later LT1 carried on the tradition of performance offered by the original and can proudly wear the name."

[55 Rescue Dog]

Well, I have had both, a 1970 LT-1 , and 2 LT1's in a 95, and 96 Impala SS. The 70 spec 11:1 LT-1, I currently have in my Camaro, I believe is pretty rare now. Originally purchased in the mid-70's as a GM crate engine. But, this one has the "turbo" angle plug heads that were never on a production car. Bought it in 1989 for $1000. It had only been ran 30 minutes, and still had assembly lube on the valve train. Did a clean up on it, and replace rings, bearings, gaskets, etc. because it sat for 35 years. Anyway, it is one REALLY great motor. The 96 LT1, is not even in the same ballpark for power! The early motor feels like a high, free revving BBC, in a 2900lb car. Yeah, I run some 110 expensive race gas, but it's still pretty cheap for the, Fun Per Miles. I don't put enough miles on it, to justify converting it to E-85, which would be great. The LT-1 will make good power to 6500rpm, or more, unlike the LT1 which was done at more like 5.

[rockytopper R.I.P 5-13-2017]

Your still comparing gen 1 engines both old lol the newest lt1 turns to 6000 rpm and puts out 460 hp 465 trq.
http://m.chevrolet.com/performance/crate-engines/lt1.html#.Vu1UcFI8KnM

[chevynut]

The 96 LT1, is not even in the same ballpark for power! The LT-1 will make good power to 6500rpm, or more, unlike the LT1 which was done at more like 5.

So how do you reconcile the article I posted that says they produce essentially the same HP? They did dyno testing on actual engines, did you?

"Despite a factory (gross) rating of 370 hp, the LT-1 produced almost exactly the same peak power as the LT1, with a peak of 353 hp at 5,600 rpm. In the torque department, the '70 LT-1 offered 292 lb-ft at 4,100 rpm, bettering the LT1 by as much as 13 lb-ft. Torque production from the LT-1 exceeded 350 lb-ft all the way up to 5,300 rpm, but like the LT1, power output from the LT-1 fell flat past 5,000 rpm."

[chevynut]

Your still comparing gen 1 engines both old lol the newest lt1 turns to 6000 rpm and puts out 460 hp 465 trq.

Yes, it's a whole different ballgame with the new LT1. It has direct injection and VVT. It's also 6.2 liters, not the 5.7 liters of the older LT-1 engines.

http://www.chevrolet.com/performance/crate-engines/lt1.html

"The LT1 is architecturally similar to the LS family of small-block engines, but with a unique block casting, cylinder head design, oiling system, and more. It also combines advanced technologies including Direct Injection and continuously Variable Valve Timing to support an advanced combustion system."

[chevynut]

Here's a great writeup on the "Gen 5" LT1 engine. I was surprised that the cam seems so small in terms of duration, but has good lift. I'm also not real keen on powdered metal rods in a performance engine but maybe the technology has significantly improved.

http://www.superchevy.com/news/ghtp-1210-gen5-inside-gms-all-new-lt1-small-block/
"Camshaft: The Gen 5 LT1 camshaft features 200/207 degrees of duration at .050-inches, .551/.524-inches of lift, and a 116.5-degree lobe separation angle. These specs are quite similar to those found on the LS3 (204/211-degrees of duration, .551/.522-inch lift, 117 LSA) although the design has been optimized for the splayed valves, 1.8-ratio rockers, and the AFM system, and reversed for the new intake and exhaust valve locations."

[chevynut]

I didn't know there were FIVE generations of small-block chevys now. There was the "original" SBC from '55 to around '91, then there were the Gen 2 engines including the LT1/LT4, and the LS engines I thought were all Gen 3. However, the LS2 and LS7 are apparently Gen 4 engines, as I assume the LS3 is as well. I didn't know there was enough difference between the LS-1 and it's successors to call them a different generation. What are the big differences between Gen3 and Gen4 LS engines?

https://en.wikipedia.org/wiki/Chevrolet_small-block_engine

[55 Rescue Dog]

So how do you reconcile the article I posted that says they produce essentially the same HP? They did dyno testing on actual engines, did you?

"Despite a factory (gross) rating of 370 hp, the LT-1 produced almost exactly the same peak power as the LT1, with a peak of 353 hp at 5,600 rpm. In the torque department, the '70 LT-1 offered 292 lb-ft at 4,100 rpm, bettering the LT1 by as much as 13 lb-ft. Torque production from the LT-1 exceeded 350 lb-ft all the way up to 5,300 rpm, but like the LT1, power output from the LT-1 fell flat past 5,000 rpm."
Doesn't matter what the dyno says, the difference between the 2 engines is very obvious, on my dyno...The Road.

[chevynut]

Doesn't matter what the dyno says, the difference between the 2 engines is very obvious, on my dyno...The Road.

Oh now that's hilarious. So now you don't believe what a dyno says, because it doesn't match your "opinion". That's rich. ;)

[55 Rescue Dog]

The LT1 had more than one version. The spec on the 1996 5.7 LT1 Impala SS was 330ftlb @2400, 260hp @ 5000rpm. Big difference, no matter what the actual numbers are compared to my new, original 1970 LT-1, that "feels" like it has at least 100 more HP, compared to that motor. Can't feel the power on the dyno, just look at it. They can juggle numbers, and tests around in magazine articles too, to make the story more interesting.

[rockytopper R.I.P 5-13-2017]

My nephew has a 1970 caprice project car with the 300 hp 350. I assume the same LT1 discussed here?

[55 Rescue Dog]

My nephew has a 1970 caprice project car with the 300 hp 350. I assume the same LT1 discussed here?
That was a good motor too, but the LT-1 had a steel crank, "pink rods" 11:1 forged pistons, good heads, solid lifter cam, and a lot more power, just to name most of the differences. The 300hp motors, I think were L79, or something. A very smooth, with wide usable power, that was actually a better comparison for the later model LT1, no matter what the numbers say, the LT-1 was a different rodent.
All, any of the old high compression engines need, is a closed loop EFI system running on E-85 with aluminum heads, and a roller cam, and they will hold their own. Of course, that will only be another $5000, sir.

[markm]

A 300 hp 350 has a .390/.410 lift juice cam cast flat top pistons 1.50/1.94 valves cast iron q-jet intake a real LT-1 has forged 11-1s, solid lifter 30-30 cam, 2.02.1.60 valves, screw in studs, alum high rise, 780 cfm Holley, apples and oranges difference I could be wrong but I know a 300 hp is not an L-79 that a 350hp 327, I think they are LM-1s.

[Fladiver64]

Difference between Gen 3 and Gen 4 LS motors

The Gen IV differences vs Gen III

58x relutor wheel (crank trigger)
Front mounted 4x Cam sensor (mounted on timing cover)
VVT (variable Valve Timing) Oil operated cam phaser on front of cam sprocket
AFM (Active Fuel Management) Deactivates 4 cly to improve MPG
Side of block mounted Knock sensors
Enhanced ECM's with separate TCM for the transmission.
Returnless Fuel Injection with Stainless Steel Fuel Rail
Advanced DBW with no TAC box needed


I have been looking into this as I would really like to have the VVT and DBW throttle, which is available on some of the trunk engines without the AFM. I know many do not like the VVT because you can make a better race engine without it, but as a street car I think this is a great technology. That is until we can get this technology on a street car http://scarbsf1.com/valves.html

[markm]

First gen SBC was 55-86, 87-96 has TPI or TBI, raised rail semi vortec cyl heads, one piece rear main. third gen 96-01 full vortec heads direct port.

[Rick_L]

There is a huge flaw in these arguments when you compare factory rated horsepower and torque.

Prior to 1971/72, the auto manufacturers rated their engine power at what's called "standard temperature and pressure" (STP). That's 60 degrees F. and 14.7 psi barometric pressure with dry air (no humidity). After that, engines were rated at "SAE conditions" which is at 85 degrees F. and 14.5 psi barometric pressure with a realistic humidity. Also the later engines are rated with the engine driven accessories in place. The weather differences alone make a difference of just over 10%.

Now having said that, the old solid lifter engine will rev higher and make more power at high revs than the new one. It also sucks for low end torque, driveability, and fuel mileage compared to the new engine.

Keep E85 out of the argument, that is a mod for either engine - and that mod could be done to either.

The old engine's solid lifter cam could be replaced by a hydraulic roller that would let it keep its peak power and improve the low end torque. The new engine's hydraulic roller could be replaced by the same bigger hydraulic roller that would improve high rpm power. Then that situation would equalize.

Likewise the heads are similar. The late engine's aluminum heads are probably slightly better out of the box than the old iron heads. Some very moderate porting on both would make both better and equalize the head situation.

The later engine's EFI results in better starting, driveability, and mileage but won't top the carb in power. A bigger throttle body might help slightly if it had a big cam and lots of rpm.

[Rick_L]

Most SBC heads after 1970 were junk until the 90s. The biggest problem is huge combustion chambers which limit compression ratio. Some had even bigger problems with the port design.

The 86-95 heads that weren't LT1 were NOT "Vortec" heads, and they're junk too for the most part. This includes heads from TBI and TPI engines. LT1s came out in 1992 for Corvettes and in 93 for Camaros. They are better heads, having small combustion chambers and better ports. The "Vortec" heads came out on truck engines in 96, and has much improved bigger ports (bigger than the old LT-1) and small heart shaped combustion chambers. A 1995 TBI 350 was rated way below 200 hp, compared to 255 hp for a 96 up truck 350.

"Semi Vortec" is a totally misleading description, as the performance improvements weren't there. The only thing those heads had like real Vortec heads had was the raised valve cover rail, center bolt valve covers, and self guiding rocker arms.

96-01 Vortec heads are not "direct port" whatever you mean by that.

The difference between Gen3 and Gen4 engines is the displacement on demand and variable valve timing features. These really don't affect power, but do give you better mileage, and the VVT can give a wider torque band. A modified Gen4 engine doesn't have to use those features.

The Gen 5 engines with direct injection do have more power and economy, and a nice wide torque band.

[chevynut]

The LT1 had more than one version.

The one they tested was one version that you don't seem to agree with for some reason.


no matter what the actual numbers are compared to my new, original 1970 LT-1, that "feels" like it has at least 100 more HP, compared to that motor. Can't feel the power on the dyno, just look at it.

I suppose when you walk outside and look at the thermometer you disagree with it too? Do you believe your speedometer, oil gauge or temp gauge in your car?


They can juggle numbers, and tests around in magazine articles too, to make the story more interesting.

So did they? What would be the motivation to do so? Tell me what they "juggled". The fact is, they proved that the engines are generally the same, something you refuse to believe even with facts and data.

What you "feel" probably has more to do with car weight, gearing, and tire size than horsepower.

[chevynut]

There is a huge flaw in these arguments when you compare factory rated horsepower and torque.

First of all, I don't think we should be discussing modifications that could be made to any engine. The subject is about technology and merits of old versus new engines. E85 isn't part of this, neither are bigger cams, aftermarket heads, etc.

The article I posted compared the old LT-1 to the LT1 of the 90's in STOCK FORM on the same dyno. It showed they put out essentially the same power, despite the claims that the old engines were more powerful.

Also, it's a known fact that GM under-rated their engines in the late 60's and they changed the way they rated them later. However, for the L-88 they did specify the correct HP at a lower RPM, but not the peak HP at the higher RPM. I'm sure they did that on a lot of engines back then. However, the LT-1 test I linked resulted in lower than advertised horsepower, 353 compared to the factory 370 rating. They said the power FELL after 5000 RPM which is interesting.

[chevynut]

96-01 Vortec heads are not "direct port" whatever you mean by that.

Don't expect Mark to know much about anything later than 1972. :) :)

[markm]

353 compared to the factory 370 rating

Which LT-1 Camaro or Vette HP raring was 360 vs 370, the Vette had better flowing exhaust manifolds.

Semi Vortec

Sorry Rick I agree but take that argument up with the General, their words not mine. One thing you did not mention they are 64 CC like later heads.


Sorry I screwed up my description of that induction with the spider thing. Like Cnut say I am not an expert on this crap.

[Rick_L]

markm, the "spider thing" has nothing to do with the heads, and few use the "spider thing" fuel injection that those engines came with.

Cnut, you're ignoring the 35 or so hp that the two correction factors get you. That gets you a negative of 37 hp on the LT-1 if you correct it to SAE (333 hp). Or you could do it the other way with the LT1 going to 358 hp for the 325 hp version and 385 hp for the 350 hp version. That makes the two engines very close.

As for mods, a lot of guys do mod their engines. I was pointing out what minor mods might make either one better depending on one's goals, and how the engine performance converges to the same.

[Rick_L]

One more thing. The dyno test was run with 1-3/4" headers on both engines. If you compare the engines "as delivered" with the exhaust system that actually came on the car, the LT-1 probably wins out because it had a less restrictive exhaust system. The later engine responds very well to exhaust upgrades in the stock chassis, in fact that's the biggest difference between the higher hp Corvette LT1s and the other versions. When you put either in a 55-57 with headers, dual exhaust, and no cats, the later engine is going to do a bit better.

The other thing about the dyno test, the early engine had an electric water pump, and the late engine had an engine driven water pump. This is also significant.

[markm]

Back in the late 70s early 80s an electric water pump drive & fan was worth about a tenth in the 1/8 mile on my 67 Camaro. Never gave a damn about dynos because you don't race them.

[chevynut]

Never gave a damn about dynos because you don't race them.

You and RD are two peas in a pod. Do you believe your speedo? How about the timers at the track? :)

[chevynut]

That gets you a negative of 37 hp on the LT-1 if you correct it to SAE (333 hp). Or you could do it the other way with the LT1 going to 358 hp for the 325 hp version and 385 hp for the 350 hp version. That makes the two engines very close.

Which is precisely what the testing showed. But try getting Mark or RD to agree with that....:) They think dyno results don't matter. ;)

[markm]

You and RD are two peas in a pod. Do you believe your speedo? How about the timers at the track? :)

What speedo my Camaro has not had a cable in it since Jimmy was in the white house and my 55 who knows. Timers at the track are for the most part correct and the time slip is all that really matters.

[chevynut]

So RD and Mark both have said my Ramjet 502 is "old technology". So what is "new technology"?

The latest Gen V LT1 has the latest in technology with direct injection, VVT, EFI, cylinder deactivation, etc. The Gen IV engines had all but the direct injection, I believe. The Gen 3 engines had none of those things, but that's where they went to an aluminum block and heads and to coil on plug ignition.

So the SBC engine has evolved over time, and there has been some revolutionary changes made over time as well. I think the aluminum block and direct injection are the revolutionary changes, as well as EFI in the 80's. Most of the others are evolutionary.

The Mark IV BBC evolved from it's introduction in the mid 60's. Displacement and horsepower increased through the early 70's when it got trashed by emissions regulations.

To me, "old tech" is iron heads (few had aluminum heads in the 60's), flat lifters, carburetors, points type non-electronic distributors. There have been evolutionary changes to the BBC throughout it's life, but the one revolutionary change was EFI.

My Ramjet 502 has all the "goodies" from the 60's including better aluminum heads, larger valves, and forged crank and rods. It also contains newer technology like a steel roller cam, roller lifters, computerized ignition, Port EFI, knock sensor, O2 sensor, one-piece rear main seal, and much improved gasketing. The engine is controlled by an ECM that contains spark and injector firing information that can be programmed.

I guess I fail to see the big difference between a "modern" BBC and an LS engine aside from the aluminum block. So what is "old tech" about a Ramjet 502 that you can still buy from GMPP? I could even add coil on plug ignition if I wanted to, and the Ramjet ZL-1 even has an aluminum block and heads. The LS engines have a more sophisticated ECM, but the basic functions are available in aftermarket ECMs for a BBC.

[Rick_L]

Looks to me like you are trying to convince yourself that your oil burning marine engine is today's technology. It's not. You even had to replace the crappy marine ECU.
.

[chevynut]

Looks to me like you are trying to convince yourself that your oil burning marine engine is today's technology. It's not. You even had to replace the crappy marine ECU.
.

You are such an asshole sometimes. GM sells these as crate engines for the automotive market, just like they do the Ramjet 350. I'm addressing the one issue that I know these 502 engines have, which is the oil rings, and the new ECU makes it that much better as far as programmability. Now it's not much different than an LS-1 in terms of technology imo. At least I have something a little more modern than that wimpy old 350 HP (maybe) 92 LT1 with the "hopeitsparks" ignition you might put in your 55.... someday...if you ever work on it. LMAO!

Oh, and by the way, I never replaced "the crappy marine ECU" because I never had one.

[55 Rescue Dog]

You and RD are two peas in a pod. Do you believe your speedo? How about the timers at the track? :)
You can tune an engine with, or without a dyno. Heck, even the g-meter dyno, on my stupid phone can calculate power. But, at the end of the day, all that matters, is how it feels. Numbers, are numbers, and the dyno is bolted to the ground. I never said the ramjet was old tech. I just implied that it is too heavy, to benefit handling. I love BBC's, but they are an anchor.

[markm]

Cnut just keep polishing that antiquated turd, maybe you can convince yourself, but not me at the end of day it is still a 60 year old turd..

[Rick_L]

Cnut,

Chevy sells marine engines as automotive because they don't want to spend any money to make them into automotive engines. In other words they use existing old technology, not the latest.

As for my not so recent old tech engine, yes it's true. But I don't come on here and brag about how it's new tech. And it's only slightly more dated than yours. It's what I have, and it's not a sure thing it will be in that car when finished.

I'm just giving you the same biz you give everyone here, and you don't seem to like that.

Seems that a superior guy like you should have an LSA, LS9, or a 454 LSX. Maybe an injected Chrysler Hemi, or an injected Boss 429 Ford, or an injected SOHC Ford. Or a twin turbo LS.

[markm]

Well Rick that pretty well nailed it.