4.8L crank in LS2
I still remember my last ride in a Gen I camaro with the 302 Z motor. The thing would rev to the moon and do it all day long.
Teching In
Joined: Nov 2008
Posts: 13
Likes: 0
I'm interested in putting together this very engine combo. I'm a road course racer looking for quick revs and sustained higher RPM's. By class rules, NASA American Iron, we are HP and TQ limited based on the weight of our cars. Which means, ideally I'm looking for about 340 RWHP and 355 RWTQ. Not huge numbers, but fast reving and very reliable is important.
The LS2 block and 4.8 crank and rods appears to be an excellent combo for my needs.
Anyone have knowledge of this being completed? If so any details available?
Would a standard LS2 piston work with this combo? Expected compression ratio?
Any info would be appreciated.
Dave
The LS2 block and 4.8 crank and rods appears to be an excellent combo for my needs.
Anyone have knowledge of this being completed? If so any details available?
Would a standard LS2 piston work with this combo? Expected compression ratio?
Any info would be appreciated.
Dave
I understand that compression ratio - timing - octane - boost is all a balancing act. I won't be trying to get by on 87 octane. I know it can be done on a boosted engine, but I'm not willing to make those concessions. I have a Snow boost cooler on the setup in my signature that works well. It comes on at a slow rate over 4psi and adds progressively more W/W fluid as the boost goes up. It's not tuned to depend on meth. It works for a living and tows on occasion. The motor I'm proposing won't tow and will be in a much lighter vehicle.
If you're not planning on taking advantage of cheaper fuel, then I don't see much reason not to do what you're thinking of doing. I think at the same power levels, that is the advantage of having a larger engine underneath that blower...but I don't know that it'll get the benefits you're expecting, at least in any significant amount. I hope it does though, sounds like you may get results comparable to the mod motor Cobra guys.
I'm interested in putting together this very engine combo. I'm a road course racer looking for quick revs and sustained higher RPM's. By class rules, NASA American Iron, we are HP and TQ limited based on the weight of our cars. Which means, ideally I'm looking for about 340 RWHP and 355 RWTQ. Not huge numbers, but fast reving and very reliable is important.
The LS2 block and 4.8 crank and rods appears to be an excellent combo for my needs.
Anyone have knowledge of this being completed? If so any details available?
Would a standard LS2 piston work with this combo? Expected compression ratio?
Any info would be appreciated.
Dave
The LS2 block and 4.8 crank and rods appears to be an excellent combo for my needs.
Anyone have knowledge of this being completed? If so any details available?
Would a standard LS2 piston work with this combo? Expected compression ratio?
Any info would be appreciated.
Dave
I don't want you to think I'm trying to talk you out of it, I'm not. I'm just more or less arguing theory...mainly because I'm bored, haha.
If you're not planning on taking advantage of cheaper fuel, then I don't see much reason not to do what you're thinking of doing. I think at the same power levels, that is the advantage of having a larger engine underneath that blower...but I don't know that it'll get the benefits you're expecting, at least in any significant amount. I hope it does though, sounds like you may get results comparable to the mod motor Cobra guys.
If you're not planning on taking advantage of cheaper fuel, then I don't see much reason not to do what you're thinking of doing. I think at the same power levels, that is the advantage of having a larger engine underneath that blower...but I don't know that it'll get the benefits you're expecting, at least in any significant amount. I hope it does though, sounds like you may get results comparable to the mod motor Cobra guys.
Teching In
Joined: Feb 2007
Posts: 9
Likes: 0
If you do this I predict:
- it will cost you much more than any potential fuel savings to do the build right
- if you don't carefully plan and execute this non-standard build correctly, your engine longevity will be greatly reduced
- you are likely to see increased fuel consumption due to loss of low-end torque during normal driving
- you will make less power (maybe not much but less) than with a standard stroke
- it will cost you much more than any potential fuel savings to do the build right
- if you don't carefully plan and execute this non-standard build correctly, your engine longevity will be greatly reduced
- you are likely to see increased fuel consumption due to loss of low-end torque during normal driving
- you will make less power (maybe not much but less) than with a standard stroke
Formerly darynC-10/23/10
iTrader: (19)
Joined: Aug 2006
Posts: 2,301
Likes: 0
From: gonzales louisiana
built your motor man and when it yields great results u can slap the haters in the face with it 
ive personally ben wanting to run a 6.0 with forged 4.8 parts simply for the fact that i like to rev past the moon. with the right setup... 8500 rpms is easily do able.
ive personally ben wanting to run a 6.0 with forged 4.8 parts simply for the fact that i like to rev past the moon. with the right setup... 8500 rpms is easily do able.
If you do this I predict:
- it will cost you much more than any potential fuel savings to do the build right
- if you don't carefully plan and execute this non-standard build correctly, your engine longevity will be greatly reduced
- you are likely to see increased fuel consumption due to loss of low-end torque during normal driving
- you will make less power (maybe not much but less) than with a standard stroke
- it will cost you much more than any potential fuel savings to do the build right
- if you don't carefully plan and execute this non-standard build correctly, your engine longevity will be greatly reduced
- you are likely to see increased fuel consumption due to loss of low-end torque during normal driving
- you will make less power (maybe not much but less) than with a standard stroke
What am I missing to do the job right? Hoping to use stock 4.8 rods and crank and off the shelf 6.0L forged pistons.
+-330 cid has been powering 3500lb vehicles around effeciently for a while. I can't see where this is a problem.
You don't use all of the torque available on a 330 cid engine just to move the vehicle around. I know, at WOT, there won't be as much torque available vs a bigger engine. Blower will more than make up for the lack of CID when necessary.
LS1 Tech Stories
The Best V8 Stories One Small Block at Time
Gas Monkey Built a 6-Wheel Ferrari Testarossa With a Corvette LT4 Engine
Verdad Gallardo
7 Most Reliable High-Performance Engines GM Has Ever Built
Verdad Gallardo
Amazing '71 Camaro Restomod Is Modern Muscle Car Under the Skin
Verdad Gallardo
6 Common C5 Corvette Failures and What's Involved In Repairing Them
Pouria Savadkouei
Retro Modern Bandit Pontiac Trans AM Comes With Burt Reynolds' Autograph
Verdad Gallardo
Top 10 Greatest Cadillac V Series Performance Models Ever, Ranked
Pouria Savadkouei
Top 10 Most Powerful Chevy Trucks Ever Made!
Hennessey's New Supercharged Silverado ZR2 Has 700 HP
Verdad Gallardo
Coachbuilt N2A Anteros Is an LS2-Powered C6 Corvette In Italian Clothes
Verdad Gallardo
8500 rpm with the stock cast 4.8 crank and rods is a stupid idea anyways. So you'll need to go aftermarket. And I don't know of anyone that makes forged 3.268 stroke LS cranks.
The piston speed difference is also negligible. 77 fps for 3.268 and 85 fps for 3.622.
To run 8500 rpm with any reliability, you'll need to spend huge money on Ti valves, lightweight rockers, pushrods, lifters.
You contact the folks at Katech. I believe that the earlier CTS-VRs were 4.125x3.27, and of course, they were N/A. The cars also had a sequential gearbox to take advantage of the motor.
The team spun those things to the moon until the SCCA reined them in with rev limiters and an intake restrictor.
http://www.cadillacfaq.com/faq/answe...vrsccaform.pdf
Teching In
Joined: Nov 2008
Posts: 13
Likes: 0
Started a seperate thread, requesting info
https://ls1tech.com/forums/generatio...l#post12572479
Looking for more detailed info on the various specs of the LS engine family. Here's some of what I have
Engine.......Bore..................Stroke ..............Rod
4.8.......3.78" (96mm).......3.27" (83mm)........?
5.3.......3.8 " (96mm)........3.62" (92mm)........?
5.7.......3.9" (99mm)........3.62" (92mm).......6.098
6.0.......4.0" (101mm).......3.62" (92mm).......6.098
Anyone no where to find detailed engine specs on the LS?
Looking for rod lengths ?
Piston details, such as wrist pin location, are they all in the same location?
https://ls1tech.com/forums/generatio...l#post12572479
Looking for more detailed info on the various specs of the LS engine family. Here's some of what I have
Engine.......Bore..................Stroke ..............Rod
4.8.......3.78" (96mm).......3.27" (83mm)........?
5.3.......3.8 " (96mm)........3.62" (92mm)........?
5.7.......3.9" (99mm)........3.62" (92mm).......6.098
6.0.......4.0" (101mm).......3.62" (92mm).......6.098
Anyone no where to find detailed engine specs on the LS?
Looking for rod lengths ?
Piston details, such as wrist pin location, are they all in the same location?
Last edited by DAlgozine; Dec 2, 2009 at 09:32 PM.
On The Tree
Joined: Feb 2005
Posts: 178
Likes: 0
From: Odessa, TX
Do it! You can't get much good info on short stroke on this website as 95% of the people here are very misinformed about it. Let me show you a few examples.
Callies will make any stroke between 2.7 and 4.25. Sonny Bryant will make any stroke as well just to name a few off the top of my head.
You showed your level when you posted Jon Stewart.
People are scared of it cause it is outside the box and not the same old cookie cutter 402+ inch motor with so and so latest greatest head on it.
Starting to get pretty boring. BTW turn the stocker in my signature 7500 with stock rockers hydraulic rollers and behive springs nothing to fancy.
You showed your level when you posted Jon Stewart.
People are scared of it cause it is outside the box and not the same old cookie cutter 402+ inch motor with so and so latest greatest head on it.
Starting to get pretty boring. BTW turn the stocker in my signature 7500 with stock rockers hydraulic rollers and behive springs nothing to fancy.
I'm all for doing something unique (I'm doing a Catera V8 conversion), but I really don't see any benefit of doing this.
Teching In
Joined: Jul 2009
Posts: 47
Likes: 0
From: Southern Delaware
Started a seperate thread, requesting info
https://ls1tech.com/forums/generatio...l#post12572479
Looking for more detailed info on the various specs of the LS engine family. Here's some of what I have
Engine.......Bore..................Stroke ..............Rod
4.8.......3.78" (96mm).......3.267" (83mm)........6.275
5.3.......3.8 " (96mm)........3.62" (92mm)........?
5.7.......3.9" (99mm)........3.62" (92mm).......6.098
6.0.......4.0" (101mm).......3.62" (92mm).......6.098
Anyone no where to find detailed engine specs on the LS?
Looking for rod lengths ?
Piston details, such as wrist pin location, are they all in the same location?
https://ls1tech.com/forums/generatio...l#post12572479
Looking for more detailed info on the various specs of the LS engine family. Here's some of what I have
Engine.......Bore..................Stroke ..............Rod
4.8.......3.78" (96mm).......3.267" (83mm)........6.275
5.3.......3.8 " (96mm)........3.62" (92mm)........?
5.7.......3.9" (99mm)........3.62" (92mm).......6.098
6.0.......4.0" (101mm).......3.62" (92mm).......6.098
Anyone no where to find detailed engine specs on the LS?
Looking for rod lengths ?
Piston details, such as wrist pin location, are they all in the same location?
Build this damn thing already. It will meet all of your expectations.
Teching In
Joined: Nov 2008
Posts: 13
Likes: 0
Started a seperate thread, requesting info
https://ls1tech.com/forums/generatio...l#post12572479
Looking for more detailed info on the various specs of the LS engine family. Here's some of what I have
Engine.......Bore..................Stroke ..............Rod
4.8.......3.78" (96mm).......3.27" (83mm)........6.276
5.3.......3.8 " (96mm)........3.62" (92mm)........6.098
5.7.......3.9" (99mm)........3.62" (92mm).......6.098
6.0.......4.0" (101mm).......3.62" (92mm).......6.098
Anyone no where to find detailed engine specs on the LS?
Looking for rod lengths ?
Piston details, such as wrist pin location, are they all in the same location?
https://ls1tech.com/forums/generatio...l#post12572479
Looking for more detailed info on the various specs of the LS engine family. Here's some of what I have
Engine.......Bore..................Stroke ..............Rod
4.8.......3.78" (96mm).......3.27" (83mm)........6.276
5.3.......3.8 " (96mm)........3.62" (92mm)........6.098
5.7.......3.9" (99mm)........3.62" (92mm).......6.098
6.0.......4.0" (101mm).......3.62" (92mm).......6.098
Anyone no where to find detailed engine specs on the LS?
Looking for rod lengths ?
Piston details, such as wrist pin location, are they all in the same location?
I found some more info for those that are interested. It appears the swap can be completed without custom parts or special work.
Any leads on some non-custom parts, such as:
forged 4.8 crank and rods
LS2 block (aluminum Gen IV 6.0L )
Chicago or Indianapolis engine shop that specializes in LS engines?
http://www.gmhightechperformance.com...ory/index.html
http://forums.popularhotrodding.com/...ext/page2.html
(about halfway down the page)
http://www.enginebuildermag.com/Arti...all_block.aspx
http://forums.hybridz.org/showthread.php?t=87947
(general LS info)
You might want to consider this route....
Find a dirt cheap 4.3 iron short block. It will, of course, have the shorter stroke/long rods you are looking for. Bore the block to 3.90. Use a set of good LS1 forged pistons and your set. The stock compression height for the LS1 piston will be correct for the 4.3 crank and rods. By doing this, you will have a cheap stout iron block. If your not happy with the combination, you won't be out much money. Drop in a forged LS1 crank and rods and be done with it.
I have done a few of 3.25" stroke cranks, 6.25" rods in 400 Gen 1 SBCs. Get help from your cam manufacturer on cam selection. I know short stroke/long rod Gen 1 SBCs do not run best with wide lobe separations but a wide lobe separation is what you want in a supercharged/turbo motor as you proposed. I wouldn't have any idea how to reconcile that dilemma but I bet a quality cam manufacturer would.
Find a dirt cheap 4.3 iron short block. It will, of course, have the shorter stroke/long rods you are looking for. Bore the block to 3.90. Use a set of good LS1 forged pistons and your set. The stock compression height for the LS1 piston will be correct for the 4.3 crank and rods. By doing this, you will have a cheap stout iron block. If your not happy with the combination, you won't be out much money. Drop in a forged LS1 crank and rods and be done with it.
I have done a few of 3.25" stroke cranks, 6.25" rods in 400 Gen 1 SBCs. Get help from your cam manufacturer on cam selection. I know short stroke/long rod Gen 1 SBCs do not run best with wide lobe separations but a wide lobe separation is what you want in a supercharged/turbo motor as you proposed. I wouldn't have any idea how to reconcile that dilemma but I bet a quality cam manufacturer would.
Last edited by Bilster; Dec 3, 2009 at 03:22 PM.
You showed your level when you posted Jon Stewart.
People are scared of it cause it is outside the box and not the same old cookie cutter 402+ inch motor with so and so latest greatest head on it.
Starting to get pretty boring. BTW turn the stocker in my signature 7500 with stock rockers hydraulic rollers and behive springs nothing to fancy.
No one is scared of an engine like this, and it's certainly not a new concept either. The concept is about as "outside the box" as playing darts with a blindfold on.
At first, he sounded like every other goofball who wanted to destroke their 346 so that they could theoretically turn 9000rpm no sweat, but reality is a bitch! If he was really concerned about power, he seems like he would understand a bigger engine/blower would be better option. If he was really concerned with fuel economy, he would likely just take the blower off, or just sell the truck and buy a Prius.
It sounds to me like he has some money to burn, and it's just a little experiment to see what happens more than anything. In that case, I say go for it, but the way the idea was presented in post number one left me looking like that picture of Jon Stewart.
This isn't a 2.8hp/ci engine, so what do you care? It's not a "real" engine to you...
LOL, my level? Haha, give me a break.
At first, he sounded like every other goofball who wanted to destroke their 346 so that they could theoretically turn 9000rpm no sweat, but reality is a bitch! If he was really concerned about power, he seems like he would understand a bigger engine/blower would be better option. If he was really concerned with fuel economy, he would likely just take the blower off, or just sell the truck and buy a Prius.
It sounds to me like he has some money to burn, and it's just a little experiment to see what happens more than anything. In that case, I say go for it, but the way the idea was presented in post number one left me looking like that picture of Jon Stewart.
This isn't a 2.8hp/ci engine, so what do you care? It's not a "real" engine to you...
At first, he sounded like every other goofball who wanted to destroke their 346 so that they could theoretically turn 9000rpm no sweat, but reality is a bitch! If he was really concerned about power, he seems like he would understand a bigger engine/blower would be better option. If he was really concerned with fuel economy, he would likely just take the blower off, or just sell the truck and buy a Prius.
It sounds to me like he has some money to burn, and it's just a little experiment to see what happens more than anything. In that case, I say go for it, but the way the idea was presented in post number one left me looking like that picture of Jon Stewart.
This isn't a 2.8hp/ci engine, so what do you care? It's not a "real" engine to you...
Again, the engine isn't going in a 5000 lb truck. More like 3500 lb car. That 6.0L in my sig is doing fine and is where the idea came from to do this build. I could put a 7.0L motor under that blower and it wouldn't make any more power, just eat more fuel. The blower only has so much capacity. It can provide provide enough air to make similer power in a 5.3L motor with the same or slightly higher boost.
I don't have money to burn. If this thing goes together like I hope it will, nothing more than a rebuild with forged pistons will be involved.
Where did I come off as some "goofball" that wanted to turn 9000 rpm? What's goofy about sizing an engine to the job? I understand a bigger engine is capable of more power.....who doesn't? What would taking the blower off have to do with the engine being more effecient? The beauty of what I'm trying to do comes with making good power (because of the blower) and not burning too much fuel (because of the smaller engine size and lighter aluminum block). If you can make the power you're looking for with less engine size, it will burn less fuel. If that's too far out in left field for you, please accept my appologies.....again. Please review post #7 in this thread.
Again, the engine isn't going in a 5000 lb truck. More like 3500 lb car. That 6.0L in my sig is doing fine and is where the idea came from to do this build. I could put a 7.0L motor under that blower and it wouldn't make any more power, just eat more fuel. The blower only has so much capacity. It can provide provide enough air to make similer power in a 5.3L motor with the same or slightly higher boost.
I don't have money to burn. If this thing goes together like I hope it will, nothing more than a rebuild with forged pistons will be involved.
Again, the engine isn't going in a 5000 lb truck. More like 3500 lb car. That 6.0L in my sig is doing fine and is where the idea came from to do this build. I could put a 7.0L motor under that blower and it wouldn't make any more power, just eat more fuel. The blower only has so much capacity. It can provide provide enough air to make similer power in a 5.3L motor with the same or slightly higher boost.
I don't have money to burn. If this thing goes together like I hope it will, nothing more than a rebuild with forged pistons will be involved.
Engine efficiency is a very vague and ambiguous term, and doesn't always equate to fuel economy. Some people look at Wankels as efficient engines... Since fuel consumption is directly related to the mass of air an engine consumes, taking off the blower, effectively reducing the amount of air ingested, will decrease the fuel consumption. From what I understand about engine dynamics, engine size is only slightly related to fuel economy, with respect to friction. It's more important to look at the amount of air being ingested and even BSFC numbers. Even though it is a smaller engine, it will be ingesting the same amount of air thanks to the blower, but that is at WOT and high loads. Cruising and part throttle may be slightly different, but how much, I couldn't tell you, because that would even take into account driving habits, as previously mentioned. It's really hard to say without tightly controlling all of the variables.
On The Tree
Joined: Feb 2005
Posts: 178
Likes: 0
From: Odessa, TX
Stop and think about it. A new ZO6 made 505hp at 427 ci. A new ZR1 made 635 hp at 370ci (Alot less stroke and a hair of bore) with a blower. I wonder why GM didn't make the ZR1 a 427 with a blower and just detune it to make 635. Oh yeah by the way I consider both of those real motors cause the mass produce them so people can use the technology from the 2.8 hp/ci motors.