LS2 experts PLEASE chime in....
Thread Starter
Drifting
Joined: Aug 2001
Posts: 1,606
Likes: 14
From: Vacaville, CA
LS2 experts PLEASE chime in....
I'm in the process of building a hot rod '69 vette....nice SRIII tube frame with a C-4 suspension. I was planning on a crate 540 from Bill Mitchell hardcore racing, but all the extra weight up front will cripple the handling.
I saw this complete LS2 w/Tremec 6-sp and got excited and bid on it....
http://cgi.ebay.com/ebaymotors/LS2-E...32895151QQrdZ1
I then realized that the LS2 Corvette intake is way different that this engine from an SSR pick-up. My question(s) are: are the internals different on this motor that a LS-2 or is it just the intake and accesory drive that's different.
There is also a brand new LS-6 motor with a Buy it now for around 7,500.
I guess I just got excited on this one since its only got 12 miles on it and includes a complete accessory drive and complete transmission. Can I just wap the intake and alternator mount, add some FI covers and have a Corvette style LS2???
Thoughts and recommendations please.
I saw this complete LS2 w/Tremec 6-sp and got excited and bid on it....
http://cgi.ebay.com/ebaymotors/LS2-E...32895151QQrdZ1
I then realized that the LS2 Corvette intake is way different that this engine from an SSR pick-up. My question(s) are: are the internals different on this motor that a LS-2 or is it just the intake and accesory drive that's different.
There is also a brand new LS-6 motor with a Buy it now for around 7,500.
I guess I just got excited on this one since its only got 12 miles on it and includes a complete accessory drive and complete transmission. Can I just wap the intake and alternator mount, add some FI covers and have a Corvette style LS2???
Thoughts and recommendations please.
Le Mans Master
Joined: Oct 2002
Posts: 7,098
Likes: 378
From: Las Vegas - Just stop perpetuating myths please.
Doctor said to reduce my caffine and it helps dealing with the LS-X ideas.
Not an LS-Xpert myself but those aluminum blocks with long rod assemblies look temping. Then i came accross the block weights in my GMPP catalogue to find the LS-X blocks only 100lbs lighter than the good o'le pig iron small blocks. 
Read that a machinist that knows what he's doing can reduce that to 60lbs or only 50lbs heavier - no can't recall where i read that so take or leave it. Of course a BB is a lot more weight and not good subsitute even on a diet.
I think ur asking if a GEN I (or GEN II) internals are the same as the LS-X engs (which is GEN III of course). No, nothing interchanges if thats what ur asking.
But really if u have the fever for c.i.'s then the aftermarket iron castings (World Products) blocks with tall decks pushing 427 or more cubes are getting popular and have a lot less interchange headaches to deal with. Not really anymore expensive than a good LS-X eng along with all the required custom parts like headers, mtr mounts, ign, induction(?).
Anyways sounds like u have a b..tch'n '69 in the works and good luck Rocket.
cardo0
Read that a machinist that knows what he's doing can reduce that to 60lbs or only 50lbs heavier - no can't recall where i read that so take or leave it. Of course a BB is a lot more weight and not good subsitute even on a diet.I think ur asking if a GEN I (or GEN II) internals are the same as the LS-X engs (which is GEN III of course). No, nothing interchanges if thats what ur asking.
But really if u have the fever for c.i.'s then the aftermarket iron castings (World Products) blocks with tall decks pushing 427 or more cubes are getting popular and have a lot less interchange headaches to deal with.
Not really anymore expensive than a good LS-X eng along with all the required custom parts like headers, mtr mounts, ign, induction(?).Anyways sounds like u have a b..tch'n '69 in the works and good luck Rocket.
cardo0
Le Mans Master
Joined: Feb 1999
Posts: 5,877
Likes: 1
From: Park Ridge IL
http://www.gmhightechperformance.com...s/0405htp_ls2/
GM says the LS2 is built on the new Gen IV small-block architecture. The primary difference between it and the previous Gen III engines is a new block casting. It actually is just a revised version of the Gen III's cylinder case. In fact, the blocks are so similar that many of the Gen III parts carry over, including LS6-style cylinder heads used on the LS2. Here are the differences between the Gen III and Gen IV blocks: Aluminum and iron (truck) versions are cast with new oil galleries to facilitate Displacement on Demand technology.
Engine knock sensors relocated from cylinder bank valley to external locations. Camshaft position sensor relocated from the rear of the block to the front. Cylinder bores increased from 3.90 inches to 4.00 inches (LS2 applications). Similar to the LS6 block, the PCV valve was moved from the rocker covers to inside the valley.
The remainder of the block's features, from the six-bolt main bearing cap design (four vertical bolts and two cross-bolts) and deep-skirted case remain unchanged.
At the bottom of the block, LS2 engines installed in Corvettes receive a revised oil pan. Redesigned interior baffles in the pan are designed to ensure an adequate oil supply to the oil pump pick-up during high-load cornering maneuvers. The previous Corvette/LS1 combination used a "gull wing" oil pan design, but oil starvation was an issue that more than one enthusiast encountered on the racetrack. With the new, wingless oil pan design, the Corvette's oil capacity is reduced from 6.5 quarts to 5.5 quarts (with a dry filter).
SHORT BLOCK
Complementing the revised engine block is a new reciprocating assembly for the LS2. The crankshaft still delivers a 3.62-inch stroke, but the pistons have a true flat-top design and rings with lower tension. Lower tension reduces friction to free up horsepower.
The LS2's pistons also have full floating wrist pins that help reduce the piston "slap" noise that's common to Gen III engines. Interestingly some customers, particularly truck owners, have complained about piston slap, but there's no real evidence to indicate it causes premature engine wear--we know of a couple Gen III-powered GMC pickups at the GM Proving Ground, outside Detroit, that each have more than 400,000 miles on their original Vortec engines.
Another LS6 carryover part is the high-lift camshaft, which helps greatly in the department covered by the next section of our story.
CYLINDER HEADS
The new, 6.0-liter LS2 taps into a pair of proven winners in the breathing department: the Corvette Z06-derived LS6 cylinder heads. Compared to the standard LS1 heads, the LS6-style lungs feature raised intake ports and a combustion chamber design with unshrouded valves. This design, GM claims, when combined with the engine's flat-top pistons, produces a more efficient swirl of the air/fuel mixture. This efficiency allows a higher, 10.9:1 compression ratio--vs. 10.1:1 on the LS1 and 10.5:1 on the LS6--helping the engine attain 400 horsepower and, we're told, better fuel economy than the smaller-displacement LS1.
Like the LS6, the LS2's valves measure 2.00 inches for the intake and 1.55 inches for the exhaust. The valve springs are designed to handle the engine's 6500-rpm rev range. It's the engine's comparatively high compression ratio--a level not seen in some time on a performance-oriented V-8--that surely will have turbo and supercharger manufacturers wondering how much boost can be put to the LS2 before it arrives at Detonation City. At first blush, we'd think not too much!
THROTTLE BODY AND INTAKE MANIFOLD
All Gen IV small-blocks receive a new throttle body; for the LS2 it's a huge, single-blade 90mm design that incorporates a motor to actuate the throttle's operation with electronic throttle control (ETC).
All LS2 engines will have electronic throttle control, which dispenses with the traditional cable-operated throttle operation. Instead, input from the gas pedal tells the computer how much throttle movement is needed.
Those with an extra-large throttle body on their high-powered LS1 (or LT1 for that matter) know that single-blade designs can be a little touchy, but GM says ETC helps ensure the big, 90mm throttle body provides smooth, predictable performance. It also eliminates the need for an idle air control motor, cruise control module and the "throttle relaxer" for traction control.
The LS2's throttle body is mounted to the intake manifold on a slight upward angle to reduce water puddling at the bottom of the throttle body. The manifold itself isn't revolutionary; just an evolution of the cross-over plenum design of the LS1 and LS6. As with the Gen III versions, the LS2's manifold is made from lightweight composite material and comes in basic black.
By the way, if you've ever questioned the efficiency of this manifold design, you'll want to take a look at the new, three-valve version of the 4.6 "cammer" motor in the coming '05 Mustang; its intake manifold looks nearly identical--including the front-and-center throttle body location--to the LS1/LS6/LS2 design.
EXHAUST MANIFOLDS
A new exhaust manifold design is used for the LS2, bringing a "best of both worlds" advantage--improved flow and reduced mass. GM tells us the new manifolds are fully one-third lighter than previous designs.
Much of the change comes from reducing the wall thickness of the manifold's outlets from 4mm to 3mm. This change contributed to the overall weight loss, while give the interior passages a 4 percent increase in flow.
There are other minor design tweaks, too, to accommodate revised emissions equipment, but it's the lighter, improved flow design that is the newsworthy item here.
ACCESSORIES AND IGNITION
Many components that are standard on the LS2 found their way into production on late versions of Gen III engines. The water pump, for example, carries over, but it is different from early LS1 engines. Its revised design, with improved sealing, is said to greatly reduce the chances of a leak (it weighs less, too). Also, a stronger timing chain was incorporated into Gen III production and it carries over to the Gen IV. All-new to the Gen IV engine, however, is an improved ignition coil pack system.
The ignition system is still a coil-near-plug design, but the coil packs are more efficient and require less energy to deliver virtually the same spark energy as the LS1's coil packs.
I've been debating what to build for my new project - LSx or SBC. I've built several SBC's (and a few BBC's) but I haven't built an LSx engine yet, but that's what I decided on anyway. I looked at all the factory blocks and none of them offer what I am looking for (a 4.125" bore) with the exception of the C5R block, but I'm not going to spend $6-7k on a bare block. I also considered resleeving either the 6.0L cast iron LS truck blcok or the LS2 block, but it will cost more to resleeve it than the actual cost of the block. With all the machining required, you'll end up with a $3000 block which puts it into the realm of the dedicated aftermarket blocks. I've always used new, aftermarket blocks for my engines - the Dart Iron Eagle/Rocket block for my twin turbo SBC 427, and Dart Big M blocks for the 540's in my boat. Currently, there are limited aftermarket engine block choices for LS engines, but World Products will have their new Warhawk LS7X blocks and heads available within a month or so. I already have one of their blocks and a pair of their 12* Warhawk LS7X heads ordered.
For the engine, I decided to use the new World Products Warhawk LS7X block featuring a 9.800" deck height and a 4.125" bore. With a 4.00" stroke I can use 6.600" rod and still maintain a boost-friendly 1.200" compression height piston, yielding a nice 1.65 r/s ratio. Unfortunately, it appears it is not available yet and is on backorder...I called World Products yesterday and was told that the LS7X blocks and heads would not be available until March, so there's going to be a delay in getting my engine program going.
The Warhawk LS7X block is constructed of 357-T6 aircraft aluminum alloy and features 2 additional head studs per cylinder (6 per cylinder total). This is what really convinced me to spend the extra money on this block versus just going with the 6.0L cast iron LS1 block, plus the aluminum block will offset the weight added to the front of the car by the turbo system. I had pretty much ruled out using one of the production aluminum LSx blocks due to the risk of lifting heads or blowing head gaskets since they only use 4 studs per cylinder and there have been reports of pulling/stretching the threads in the block. My last 427TT made between 22-25 psi of boost and I'm planning the same for this one, maybe a little more.
The LS7X block also has both the LS1 and SBC motor mounts cast in, so no worries about using adapter mounts or relocating the mounting ears on the frame. It uses the same billet steel main caps with 200,000psi ARP studs/bolts as the C5R, priority main oiling, dry sump compatible, and will take up to a 4.250" stroke. It uses standard LSx series accesories.
For heads, I am going to use the Warhawk LS7X 12* heads. They also accept the 2 extra heads per cylinder and feature 255cc intake ports with 64cc C5R chambers. 2.200" intake valves and 1.625" exhaust valves. My first TT 427 featured 257cc intakes runners and 2.180" intake valves, with the same 1.625" exhaust, so I'm expecting similar flow numbers of ~ 380cfm at .700". We'll flow bench them when we get them to confirm. The LS7X heads utilize standard LS7 valvetrain components, but I'll probably use Jesel shaft rockers again and either Jesel or Isky roller lifters.
GM says the LS2 is built on the new Gen IV small-block architecture. The primary difference between it and the previous Gen III engines is a new block casting. It actually is just a revised version of the Gen III's cylinder case. In fact, the blocks are so similar that many of the Gen III parts carry over, including LS6-style cylinder heads used on the LS2. Here are the differences between the Gen III and Gen IV blocks: Aluminum and iron (truck) versions are cast with new oil galleries to facilitate Displacement on Demand technology.
Engine knock sensors relocated from cylinder bank valley to external locations. Camshaft position sensor relocated from the rear of the block to the front. Cylinder bores increased from 3.90 inches to 4.00 inches (LS2 applications). Similar to the LS6 block, the PCV valve was moved from the rocker covers to inside the valley.
The remainder of the block's features, from the six-bolt main bearing cap design (four vertical bolts and two cross-bolts) and deep-skirted case remain unchanged.
At the bottom of the block, LS2 engines installed in Corvettes receive a revised oil pan. Redesigned interior baffles in the pan are designed to ensure an adequate oil supply to the oil pump pick-up during high-load cornering maneuvers. The previous Corvette/LS1 combination used a "gull wing" oil pan design, but oil starvation was an issue that more than one enthusiast encountered on the racetrack. With the new, wingless oil pan design, the Corvette's oil capacity is reduced from 6.5 quarts to 5.5 quarts (with a dry filter).
SHORT BLOCK
Complementing the revised engine block is a new reciprocating assembly for the LS2. The crankshaft still delivers a 3.62-inch stroke, but the pistons have a true flat-top design and rings with lower tension. Lower tension reduces friction to free up horsepower.
The LS2's pistons also have full floating wrist pins that help reduce the piston "slap" noise that's common to Gen III engines. Interestingly some customers, particularly truck owners, have complained about piston slap, but there's no real evidence to indicate it causes premature engine wear--we know of a couple Gen III-powered GMC pickups at the GM Proving Ground, outside Detroit, that each have more than 400,000 miles on their original Vortec engines.
Another LS6 carryover part is the high-lift camshaft, which helps greatly in the department covered by the next section of our story.
CYLINDER HEADS
The new, 6.0-liter LS2 taps into a pair of proven winners in the breathing department: the Corvette Z06-derived LS6 cylinder heads. Compared to the standard LS1 heads, the LS6-style lungs feature raised intake ports and a combustion chamber design with unshrouded valves. This design, GM claims, when combined with the engine's flat-top pistons, produces a more efficient swirl of the air/fuel mixture. This efficiency allows a higher, 10.9:1 compression ratio--vs. 10.1:1 on the LS1 and 10.5:1 on the LS6--helping the engine attain 400 horsepower and, we're told, better fuel economy than the smaller-displacement LS1.
Like the LS6, the LS2's valves measure 2.00 inches for the intake and 1.55 inches for the exhaust. The valve springs are designed to handle the engine's 6500-rpm rev range. It's the engine's comparatively high compression ratio--a level not seen in some time on a performance-oriented V-8--that surely will have turbo and supercharger manufacturers wondering how much boost can be put to the LS2 before it arrives at Detonation City. At first blush, we'd think not too much!
THROTTLE BODY AND INTAKE MANIFOLD
All Gen IV small-blocks receive a new throttle body; for the LS2 it's a huge, single-blade 90mm design that incorporates a motor to actuate the throttle's operation with electronic throttle control (ETC).
All LS2 engines will have electronic throttle control, which dispenses with the traditional cable-operated throttle operation. Instead, input from the gas pedal tells the computer how much throttle movement is needed.
Those with an extra-large throttle body on their high-powered LS1 (or LT1 for that matter) know that single-blade designs can be a little touchy, but GM says ETC helps ensure the big, 90mm throttle body provides smooth, predictable performance. It also eliminates the need for an idle air control motor, cruise control module and the "throttle relaxer" for traction control.
The LS2's throttle body is mounted to the intake manifold on a slight upward angle to reduce water puddling at the bottom of the throttle body. The manifold itself isn't revolutionary; just an evolution of the cross-over plenum design of the LS1 and LS6. As with the Gen III versions, the LS2's manifold is made from lightweight composite material and comes in basic black.
By the way, if you've ever questioned the efficiency of this manifold design, you'll want to take a look at the new, three-valve version of the 4.6 "cammer" motor in the coming '05 Mustang; its intake manifold looks nearly identical--including the front-and-center throttle body location--to the LS1/LS6/LS2 design.
EXHAUST MANIFOLDS
A new exhaust manifold design is used for the LS2, bringing a "best of both worlds" advantage--improved flow and reduced mass. GM tells us the new manifolds are fully one-third lighter than previous designs.
Much of the change comes from reducing the wall thickness of the manifold's outlets from 4mm to 3mm. This change contributed to the overall weight loss, while give the interior passages a 4 percent increase in flow.
There are other minor design tweaks, too, to accommodate revised emissions equipment, but it's the lighter, improved flow design that is the newsworthy item here.
ACCESSORIES AND IGNITION
Many components that are standard on the LS2 found their way into production on late versions of Gen III engines. The water pump, for example, carries over, but it is different from early LS1 engines. Its revised design, with improved sealing, is said to greatly reduce the chances of a leak (it weighs less, too). Also, a stronger timing chain was incorporated into Gen III production and it carries over to the Gen IV. All-new to the Gen IV engine, however, is an improved ignition coil pack system.
The ignition system is still a coil-near-plug design, but the coil packs are more efficient and require less energy to deliver virtually the same spark energy as the LS1's coil packs.
I've been debating what to build for my new project - LSx or SBC. I've built several SBC's (and a few BBC's) but I haven't built an LSx engine yet, but that's what I decided on anyway. I looked at all the factory blocks and none of them offer what I am looking for (a 4.125" bore) with the exception of the C5R block, but I'm not going to spend $6-7k on a bare block. I also considered resleeving either the 6.0L cast iron LS truck blcok or the LS2 block, but it will cost more to resleeve it than the actual cost of the block. With all the machining required, you'll end up with a $3000 block which puts it into the realm of the dedicated aftermarket blocks. I've always used new, aftermarket blocks for my engines - the Dart Iron Eagle/Rocket block for my twin turbo SBC 427, and Dart Big M blocks for the 540's in my boat. Currently, there are limited aftermarket engine block choices for LS engines, but World Products will have their new Warhawk LS7X blocks and heads available within a month or so. I already have one of their blocks and a pair of their 12* Warhawk LS7X heads ordered.
For the engine, I decided to use the new World Products Warhawk LS7X block featuring a 9.800" deck height and a 4.125" bore. With a 4.00" stroke I can use 6.600" rod and still maintain a boost-friendly 1.200" compression height piston, yielding a nice 1.65 r/s ratio. Unfortunately, it appears it is not available yet and is on backorder...I called World Products yesterday and was told that the LS7X blocks and heads would not be available until March, so there's going to be a delay in getting my engine program going.
The Warhawk LS7X block is constructed of 357-T6 aircraft aluminum alloy and features 2 additional head studs per cylinder (6 per cylinder total). This is what really convinced me to spend the extra money on this block versus just going with the 6.0L cast iron LS1 block, plus the aluminum block will offset the weight added to the front of the car by the turbo system. I had pretty much ruled out using one of the production aluminum LSx blocks due to the risk of lifting heads or blowing head gaskets since they only use 4 studs per cylinder and there have been reports of pulling/stretching the threads in the block. My last 427TT made between 22-25 psi of boost and I'm planning the same for this one, maybe a little more.
The LS7X block also has both the LS1 and SBC motor mounts cast in, so no worries about using adapter mounts or relocating the mounting ears on the frame. It uses the same billet steel main caps with 200,000psi ARP studs/bolts as the C5R, priority main oiling, dry sump compatible, and will take up to a 4.250" stroke. It uses standard LSx series accesories.
For heads, I am going to use the Warhawk LS7X 12* heads. They also accept the 2 extra heads per cylinder and feature 255cc intake ports with 64cc C5R chambers. 2.200" intake valves and 1.625" exhaust valves. My first TT 427 featured 257cc intakes runners and 2.180" intake valves, with the same 1.625" exhaust, so I'm expecting similar flow numbers of ~ 380cfm at .700". We'll flow bench them when we get them to confirm. The LS7X heads utilize standard LS7 valvetrain components, but I'll probably use Jesel shaft rockers again and either Jesel or Isky roller lifters.
Team Owner
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From: Guinness Its whats for B'fast JAWGA
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From: Alexandria, Virginia, USA VA
couple other considerations too. I think the later LS2s went to a different crank position wheel and computer setup.
there is a new "deck plate" setup (pricey) that allows a whopping 500 ci LS2. with some of the new canted valve heads that flow 400 cfm intake flow you could make some serious power.
I like the warhawk idea. I have been thinking about a twin turbo kit car (factory five) and the warhawk build would be expensive, but likely hold 1k hp very well. problem is that it will never hook up!!!
I also have an old corvette (1980) drag car with a modified stock frame/tube chassis, 4 link modular 9". I currently run a BB chevy with a flying toilet and alchy. thinking about someday going to a turbo LSx archetecture to really lighten up this pig (2900 lbs). going to lexan glass, and probably alum heads to save a couple hundred pounds but the LSx would knock probably another 200 lbs off in comparison to the big block. I think the warhawk block has the stock chevy bolt pattern too to allow my race t400 to bolt up.
thanks monty for the very informative post. fyi, vette, hot rodding, and hot rod all have some cool info this month about new LSx blocks, heads, deck plate short blocks, ect...
till this stuff goes a bit more mainstream, I'll stick with the old BB chevy for racing and th LPE LT5 (620 HP) for the ZR-1 on the street!!
cya+
there is a new "deck plate" setup (pricey) that allows a whopping 500 ci LS2. with some of the new canted valve heads that flow 400 cfm intake flow you could make some serious power.
I like the warhawk idea. I have been thinking about a twin turbo kit car (factory five) and the warhawk build would be expensive, but likely hold 1k hp very well. problem is that it will never hook up!!!
I also have an old corvette (1980) drag car with a modified stock frame/tube chassis, 4 link modular 9". I currently run a BB chevy with a flying toilet and alchy. thinking about someday going to a turbo LSx archetecture to really lighten up this pig (2900 lbs). going to lexan glass, and probably alum heads to save a couple hundred pounds but the LSx would knock probably another 200 lbs off in comparison to the big block. I think the warhawk block has the stock chevy bolt pattern too to allow my race t400 to bolt up.
thanks monty for the very informative post. fyi, vette, hot rodding, and hot rod all have some cool info this month about new LSx blocks, heads, deck plate short blocks, ect...
till this stuff goes a bit more mainstream, I'll stick with the old BB chevy for racing and th LPE LT5 (620 HP) for the ZR-1 on the street!!
cya+
