What Makes the LS-1 Better than LT-1?
07-04-2007, 03:43 AM
#21
Team Owner
The LSx shares no specs with the SBC other than bore spacing. It was a totally clean-sheet design, whereas the the LTx engines were more of a stop-gap transition engine that just so happened to provide excellent performance. Some other benefits of the LSx:
Rifle-bored camshaft
Rigid, stress-bearing oil-pan
Lighter, polymer intake
Coil-on-plug ignition
Rifle-bored camshaft
Rigid, stress-bearing oil-pan
Lighter, polymer intake
Coil-on-plug ignition
07-04-2007, 11:10 AM
#23
Melting Slicks
just some interesting history and tidbits on the evolution from LT to LS engine:
The LT1 came out in 1992 in the Corvette and 1993 in the Camaro. These motors are non sequential injection system(batch fired) with the non-programmable computer. These engines make just as much power as later LT1s, but do not have the tune-ability. They must be "chipped" to change parameters. The only smog equipment for 1992 and 1993 is the electric smog pump, single catalityc converter and the Evap system purge solenoid on the intake manifold.
In 1994, LT1s became sequentially fired and had fully programmable computers that can be modified with programs like LT1edit and Cat Tunerz. These are considered the first OBD1 engines. In addition to previous smog equipment, the LT1 now has an EGR valve on the back of the intake manifold.
In 1995 the LT1 got an improved optispark distributor that is also much cheaper to replace if need be. In 1995 the LT1 began using an OBDII style connector but were still OBD1, meaning that you can still use Cat Tunerz and LT1edit to modify the computer.
1996 was the first year for the OBDII LT1 engine. Everything on the engine remained the same except for a modified timing cover with a crank sensor in the front of it. The computer for 1996 is all new and requires much more expensive software to tune. LT1edit makes software for the OBDII computers. The OBDII computers also have downstream O2 sensors which previous LT1s never had.
No changes were made to the LT1 in 1997.
The LT4 was a 1 year run engine that can only be found in 1996 special eddition Corvettes and Gran Sport Corvettes. The LT4 is the same as an LT1 with improved flowing cylinder heads, improved camshaft, and an improved intake manifold.
All LT1 corvettes had 4 bolt main caps. All Corvettes had aluminum heads.
All Caprices, Impalas, Roadmasters, and Fleetwoods had 2 bolt main caps with Iron heads except for the Police version of the Caprice with the B4C package that had Aluminum heads.
1997 was the last year for the iron block LT1 and the first year of the brand new all aluminum LS1.
All LS1 engines are OBDII and respond greatly to tuning. HPTuners and LT1Edit are the premier tuning programs for these engines.
LS1s are equiped with 2 catalitic converters, an electric air pump and an Evap purge solenoid. EGR valves were used from 1998-2000 in the camaro and then dropped for the 2001-2002 model year where the LS6 intake manifold was used in its spot. Corvettes did not use an EGR valve in 1997 but did use it from 1998-2000. None of the LS6 engines ever had an EGR valve and neither did the LS2 engines.
The LT1 came out in 1992 in the Corvette and 1993 in the Camaro. These motors are non sequential injection system(batch fired) with the non-programmable computer. These engines make just as much power as later LT1s, but do not have the tune-ability. They must be "chipped" to change parameters. The only smog equipment for 1992 and 1993 is the electric smog pump, single catalityc converter and the Evap system purge solenoid on the intake manifold.
In 1994, LT1s became sequentially fired and had fully programmable computers that can be modified with programs like LT1edit and Cat Tunerz. These are considered the first OBD1 engines. In addition to previous smog equipment, the LT1 now has an EGR valve on the back of the intake manifold.
In 1995 the LT1 got an improved optispark distributor that is also much cheaper to replace if need be. In 1995 the LT1 began using an OBDII style connector but were still OBD1, meaning that you can still use Cat Tunerz and LT1edit to modify the computer.
1996 was the first year for the OBDII LT1 engine. Everything on the engine remained the same except for a modified timing cover with a crank sensor in the front of it. The computer for 1996 is all new and requires much more expensive software to tune. LT1edit makes software for the OBDII computers. The OBDII computers also have downstream O2 sensors which previous LT1s never had.
No changes were made to the LT1 in 1997.
The LT4 was a 1 year run engine that can only be found in 1996 special eddition Corvettes and Gran Sport Corvettes. The LT4 is the same as an LT1 with improved flowing cylinder heads, improved camshaft, and an improved intake manifold.
All LT1 corvettes had 4 bolt main caps. All Corvettes had aluminum heads.
All Caprices, Impalas, Roadmasters, and Fleetwoods had 2 bolt main caps with Iron heads except for the Police version of the Caprice with the B4C package that had Aluminum heads.
1997 was the last year for the iron block LT1 and the first year of the brand new all aluminum LS1.
All LS1 engines are OBDII and respond greatly to tuning. HPTuners and LT1Edit are the premier tuning programs for these engines.
LS1s are equiped with 2 catalitic converters, an electric air pump and an Evap purge solenoid. EGR valves were used from 1998-2000 in the camaro and then dropped for the 2001-2002 model year where the LS6 intake manifold was used in its spot. Corvettes did not use an EGR valve in 1997 but did use it from 1998-2000. None of the LS6 engines ever had an EGR valve and neither did the LS2 engines.
07-04-2007, 04:10 PM
#24
Drifting
LSx motors are great motors no doubt and can make gobs of hp with mods. LTx motors can offer a lot of bang for the buck and definitely have a better sounding exhaust note.
07-04-2007, 04:54 PM
#25
Le Mans Master
I'm no expert, but the ability of a stock LSx to take boost seems pretty damn impressive. The L98 and LTx's certainly don't seem capable of that in stock form.
07-05-2007, 11:45 AM
#26
Team Owner
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Uh, the LSx block is about 70lbs lighter... Iron vs. aluminum. The polymer LSx intake also weighs 8-10lbs less.
Insofar as "stronger", I think they are about the same. The LSx has 6-bolt mains, but they are in aluminum vs. the 4-bolt iron in the LTx. I can tell you that the factory LSx cranks will take a hell of a beating.
Insofar as "stronger", I think they are about the same. The LSx has 6-bolt mains, but they are in aluminum vs. the 4-bolt iron in the LTx. I can tell you that the factory LSx cranks will take a hell of a beating.
07-05-2007, 01:00 PM
#27
another advantage of the LSx engines, is the cylinder head attachment design. while not necessarily directly responsible for more power production, it certainly is a superior design.
the LSx went with a more conventional 4 bolt per cyl., instead of the older 5 bolt layout, which doesnt interfere with the intake ports.
it also allowed the head bolts to be easily moved away from the edge of the cyl. bore, thus preventing any cylinder bore distortion from tightening of the head bolts...
the LSx also has a coolant "groove" in the block, between each head bolt hole, and the cyl. wall, to further eliminate any distortion of the cyl. bores.
the LSx head bolts also run deep into the block, instead of just through the deck surface, like on GEN1/2 engines...
the LSx went with a more conventional 4 bolt per cyl., instead of the older 5 bolt layout, which doesnt interfere with the intake ports.
it also allowed the head bolts to be easily moved away from the edge of the cyl. bore, thus preventing any cylinder bore distortion from tightening of the head bolts...
the LSx also has a coolant "groove" in the block, between each head bolt hole, and the cyl. wall, to further eliminate any distortion of the cyl. bores.
the LSx head bolts also run deep into the block, instead of just through the deck surface, like on GEN1/2 engines...
07-05-2007, 02:07 PM
#28
Safety Car
I think CompCams has offered to do any grind with a 4/7 swap for quite some time now. Dont know what the charge is.
07-05-2007, 02:33 PM
#29
Race Director
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Clutch tips the scales @ 49#s, and the cast iron manifolds are 13 each. Subtract this from the motor, and you get 383#s, with oil, intake, coil packs, Water pump, pan, filter, TB, you name it, sans manifolds and clutch.
TPI dressed weight in 85 was 585#s
The last LT1 I shipped was a 480, that was minus clutch and manifolds.
07-11-2007, 11:39 PM
#30
Team Owner
Pro Mechanic
Jeffvette is right; the Gen III engine is lighter.
Another detail not yet mentioned is the cam on the Gen III and Gen IV have a larger base circle and larger cam bearings, which allow for more aggressive ramp rates right from the factory. Hence the awesome lift/duration ratio's you see in the Gen III and newer motors.
Same goes for 1.7 rockers a/roller bearing fulcrum, stock.
Also "raised" cam allows for longer strokes w/o cam clearance issues.
Also, crank driven G-rotor oil pump consumes less power.
Another detail not yet mentioned is the cam on the Gen III and Gen IV have a larger base circle and larger cam bearings, which allow for more aggressive ramp rates right from the factory. Hence the awesome lift/duration ratio's you see in the Gen III and newer motors.
Same goes for 1.7 rockers a/roller bearing fulcrum, stock.
Also "raised" cam allows for longer strokes w/o cam clearance issues.
Also, crank driven G-rotor oil pump consumes less power.
Last edited by Tom400CFI; 07-12-2007 at 10:43 AM.
07-12-2007, 02:59 PM
#31
Team Owner
07-12-2007, 03:13 PM
#32
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Is all about evolution. The LT1 is better than an L83 and L98 and the LT4 is better than the LT1.
Now, I have seen few stock LT4 eat for breakfast stocks LS1.
But, the LS2 (Z06) is another story. I also have seen stock 2004 Z06 beat 2005-6 400 HP C6
But, if you grab a LS1, intall headers, cam and edelbrock heads, that sucker gets some brutal "horsepower gain".
The LT1 doesn't. My LT1 is just good enough for me and I love it.
Now, I have seen few stock LT4 eat for breakfast stocks LS1.
But, the LS2 (Z06) is another story. I also have seen stock 2004 Z06 beat 2005-6 400 HP C6
But, if you grab a LS1, intall headers, cam and edelbrock heads, that sucker gets some brutal "horsepower gain".
The LT1 doesn't. My LT1 is just good enough for me and I love it.
07-12-2007, 06:01 PM
#33
Le Mans Master
Though the LS2 is another story like you said, 400hp in a base vette.
07-13-2007, 02:34 AM
#36
Melting Slicks
LSx motors are a bit more technical than the LT1. But at least it has no Opti. One of my friends JUST NOW got stranded because of its failure when the 90k mile waterpump decided to puke coolant all over it, 97 Camaro Z28. I'll be cutting my hands open again in the morning. But hey, its good experience.
I'm for traditional SBC and LSx motors ALL the way. If I had a car with an LT1, I'd probably sell it and get one with either a traditional SBC or LSx already in it.
If I REALLY wanted the reverse cooling feature of the LT1 in my V8 S-10 pickup, I'd find a way to "fit" the traditional SBC HEI ignition and get it to work properly. But for now, its simply not worth the time and trouble. If I ever get tired of this SBC, I'm gonna swap it directly with an LS1 and figure out all the wiring sooner or later.
I'm for traditional SBC and LSx motors ALL the way. If I had a car with an LT1, I'd probably sell it and get one with either a traditional SBC or LSx already in it.
If I REALLY wanted the reverse cooling feature of the LT1 in my V8 S-10 pickup, I'd find a way to "fit" the traditional SBC HEI ignition and get it to work properly. But for now, its simply not worth the time and trouble. If I ever get tired of this SBC, I'm gonna swap it directly with an LS1 and figure out all the wiring sooner or later.
07-13-2007, 04:49 AM
#37
Team Owner
Is all about evolution. The LT1 is better than an L83 and L98 and the LT4 is better than the LT1.
Now, I have seen few stock LT4 eat for breakfast stocks LS1.
But, the LS2 (Z06) is another story. I also have seen stock 2004 Z06 beat 2005-6 400 HP C6
But, if you grab a LS1, intall headers, cam and edelbrock heads, that sucker gets some brutal "horsepower gain".
The LT1 doesn't. My LT1 is just good enough for me and I love it.
Now, I have seen few stock LT4 eat for breakfast stocks LS1.
But, the LS2 (Z06) is another story. I also have seen stock 2004 Z06 beat 2005-6 400 HP C6
But, if you grab a LS1, intall headers, cam and edelbrock heads, that sucker gets some brutal "horsepower gain".
The LT1 doesn't. My LT1 is just good enough for me and I love it.
07-13-2007, 11:46 AM
#39
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07-13-2007, 12:08 PM
#40
Melting Slicks
The advent of flow benches, CAD design, and CNC machines has all contributed to a much better design.
I think the pioneers like Dick Maskin (Dart), Ken Spurling (AFR), Bill Jenkins, and the folks at Brodix have worked very hard on cylinder head flow and made major break throughs that eventually spread and trickled down to us in the form of LS1/LS7 cylinder heads.
In the very early days, Maskin actually cut two heads in half, slightly offset, and then welded them back together to produce a larger port.
I think the pioneers like Dick Maskin (Dart), Ken Spurling (AFR), Bill Jenkins, and the folks at Brodix have worked very hard on cylinder head flow and made major break throughs that eventually spread and trickled down to us in the form of LS1/LS7 cylinder heads.
In the very early days, Maskin actually cut two heads in half, slightly offset, and then welded them back together to produce a larger port.
