i feel stupid asking, but what exactly is the LT1 and LT4, from what i understand, the LT1 is hte 93-97 Z28 engine, but LT4?
What is Lt4?
TheGr8Schlotzky
1 - 18 of 18 Posts
Joined
·
38 Posts
i feel stupid asking, but what exactly is the LT1 and LT4, from what i understand, the LT1 is hte 93-97 Z28 engine, but LT4?
Joined
·
467 Posts
The LT4 is an "evolved" LT1 engine used in Corvettes only if i'm not mistaken.
check this out: http://www.grandsportregistry.com/lt1vslt4.htm
There's an LT5 also, which is an exotic version used in the ZR1 Corvette's built between 1990 & 1995 I believe....there's plent to find about them if you google some.
check this out: http://www.grandsportregistry.com/lt1vslt4.htm
There's an LT5 also, which is an exotic version used in the ZR1 Corvette's built between 1990 & 1995 I believe....there's plent to find about them if you google some.
Joined
·
4,908 Posts
LT-1 and LT-4 are the designations for the second generation small block Chevy engine. The small block was getting long in the tooth (designed and basically unchanged since 1953) when the production engineers started to look at ways of reducing detonation. They noted that the two cylinders in the middle had the exhausts side by side concentrating the heat in that area. By bringing water in from the back of the block and flushing it out the front they were able to cool this area first.
This change necessitated a new block design. You shouldn't confuse reverse cooling with the earlier reverse rotation water pump (changed to incorporate serpentine belts). The actual direction of the water flow in the block changed.
The other significant change was the introduction of OptiSpark. This is a new distributor driven directly by the timing chain instead of off the back of the cam. This gives a more reliable spark freed from driving the oil pump. The LT-1 also got rid of the TPI manifold which had been holding the engine back from being able to hit any higher RPM's. So the LT-1 also got a new cam to reflect it's new potential (which because of the OptiSpark is different from earlier designs.
Finally the LT-1 initially introduced in the Corvette was put into the Impala SS, and people promptly started to beat up on Mustangs with a small block in a B-body. Now the Corvette has to be exclusive; so GM gave it a hot rodded version of the LT-I, with a bigger set of heads, bigger red plastic manifold and higher rated injectors with a much hotter cam. They called this minor rework the LT-4. It was only out for I think two years, before it was quickly over-shadowed, and replaced by the new 800 pound Gorilla the new gen III LS-6.
Larger Dave
This change necessitated a new block design. You shouldn't confuse reverse cooling with the earlier reverse rotation water pump (changed to incorporate serpentine belts). The actual direction of the water flow in the block changed.
The other significant change was the introduction of OptiSpark. This is a new distributor driven directly by the timing chain instead of off the back of the cam. This gives a more reliable spark freed from driving the oil pump. The LT-1 also got rid of the TPI manifold which had been holding the engine back from being able to hit any higher RPM's. So the LT-1 also got a new cam to reflect it's new potential (which because of the OptiSpark is different from earlier designs.
Finally the LT-1 initially introduced in the Corvette was put into the Impala SS, and people promptly started to beat up on Mustangs with a small block in a B-body. Now the Corvette has to be exclusive; so GM gave it a hot rodded version of the LT-I, with a bigger set of heads, bigger red plastic manifold and higher rated injectors with a much hotter cam. They called this minor rework the LT-4. It was only out for I think two years, before it was quickly over-shadowed, and replaced by the new 800 pound Gorilla the new gen III LS-6.
Larger Dave
LT4 is a ONE year ONLY Corvette engine, 1996, the last of the C4 design
In t97 the C5 debuted with the LS1 engine, Camaro had them in 98-up
LT4 was ONLY avail with the manual trans in both the 96 Corvette AND the couple hundred 97 Anniversary Camaros that had it
Affectionally named the Grand Sport engine as the were standard in the 96 GS Corvette (blue with white stripes), although ALL 96 Corvettes had it IF you got the 6 speed manual trans
In t97 the C5 debuted with the LS1 engine, Camaro had them in 98-up
LT4 was ONLY avail with the manual trans in both the 96 Corvette AND the couple hundred 97 Anniversary Camaros that had it
Affectionally named the Grand Sport engine as the were standard in the 96 GS Corvette (blue with white stripes), although ALL 96 Corvettes had it IF you got the 6 speed manual trans
Joined
·
22,190 Posts
While that place could be hazerdous if you sprung a leak, there is also an upside.Tokala said:
LT1 / LT4 engines drive the water pump thru the optispark, directly off the camshaft.
My 94 vette broke a belt once at "0 dark early" on a road trip. Since the water pump continued to pump, I was able to continue driving, for over an hour, till I found a dealer who had the belt in stock.
Joined
·
27,011 Posts
Joined
·
2,843 Posts
At the time (1996) the LT-4 was the strongest 'production' Chevy small block ever built, at 330 HP Net. The LS1 came out the next year and had 345 HP. But, there were some side by side dyno tests in the day that showed the LT-4 actually making more HP.
Great little motor, the LT-4, but only a one-year, one-car offering.
Great little motor, the LT-4, but only a one-year, one-car offering.
The LT5 is just wicked. I saw some you tube footage of a couple of Corvettes running the 1/4 mile w/ LT5's. Low 11 second passes if I remember correctly. There's a ZR1 w/ an LT5 at our community college that has never been driven on the street or track. It's just for kids to take apart and put back together. It hurts just talking about it.
Joined
·
27,011 Posts
Not the same beast as the LT-1 or LT-4 but awesome power plant none the less...
Joined
·
2,843 Posts
Joined
·
8,305 Posts
LT1 was used in 92-96 Vettes, 93-97 Z28/Trans am, and 94-96 B bodies (Caprice, Roadsmasher, etc).
the LT4 was in 96 vettes and some 97 Z28's.
the B body LT1 has cast iron heads that were later modified for use on a regular small block i ntrucks and are known as the famous "vortec" head. the iron LT1 heads are actually better flowing and have better chambers than the aluminum heads, but the LT4 head is better than either.
there was also a 4.3 liter variation used only in 94-96 non station wagon Caprices called the L99. it had a 3" stroke and 5.94" rods that can be used with off the shelf 350 pistons in any 87 and later 350 block to build a modern 302 using factory parts. the L99 was also available in cop cars and taxis and what not, so if you are getting an engine out of one to swap into an older car, make sure it's not one of those. other than the casting numbers on the block and heads, it looks identical to an LT1 350, but it has a single exhaust and a 7.5 rear with drum brakes instead of dual exhaust and an 8.5 rear with disc brakes that every LT1 car got.
the LT4 was in 96 vettes and some 97 Z28's.
the B body LT1 has cast iron heads that were later modified for use on a regular small block i ntrucks and are known as the famous "vortec" head. the iron LT1 heads are actually better flowing and have better chambers than the aluminum heads, but the LT4 head is better than either.
there was also a 4.3 liter variation used only in 94-96 non station wagon Caprices called the L99. it had a 3" stroke and 5.94" rods that can be used with off the shelf 350 pistons in any 87 and later 350 block to build a modern 302 using factory parts. the L99 was also available in cop cars and taxis and what not, so if you are getting an engine out of one to swap into an older car, make sure it's not one of those. other than the casting numbers on the block and heads, it looks identical to an LT1 350, but it has a single exhaust and a 7.5 rear with drum brakes instead of dual exhaust and an 8.5 rear with disc brakes that every LT1 car got.
1 - 18 of 18 Posts
-
?
-
?
-
?
-
?
-
?
-
?
-
?
-
?
-
?
-
?
-
?
-
?
-
?
-
?
-
?
-
?
-
?
-
?
-
?
-
?
