LS3 or LS7
Safety Car
Joined: Oct 2004
Posts: 4,816
Likes: 132
From: Plano TX
Dude.. You are living in a fantasy world.. Alex and Toque are correct A boosted LS7 is scary.. A Ticking time bomb.. GM Engineers knew a boosted LS7 was out of the question, when they started the drawing board for the new ZR1..
Last edited by David426; Sep 20, 2011 at 10:50 AM.
Tech Contributor
Joined: Jan 2007
Posts: 19,294
Likes: 1,110
From: Dyer, IN
Vortech and Procharger.....take note ! LS7's are blowing up
........stop making compatible SC's immediately !
Thread Starter
Intermediate
Joined: May 2011
Posts: 28
Likes: 0
From: Texarkana TX
I've been researching some of the advise from the replies. What I've found so far is the ls3 is a very strong block but also read they have oiling issues on road courses. I think I'll be better off going back with 383 stroker ls6 for now.
Thanks for the help!
Thanks for the help!
Tech Contributor
Joined: Jan 2007
Posts: 19,294
Likes: 1,110
From: Dyer, IN
Race Director
Joined: Jul 2007
Posts: 11,467
Likes: 8
From: 972 and 405
Man, you are right. All the shops have stopped selling the kits, and all the shops have stopped installing superchargers on C6Z06's. They are blowing up left and right...............just my fantasy I guess.
Vortech and Procharger.....take note ! LS7's are blowing up........stop making compatible SC's immediately !
Vortech and Procharger.....take note ! LS7's are blowing up
........stop making compatible SC's immediately !-Alex
Race Director
Joined: Jul 2007
Posts: 11,467
Likes: 8
From: 972 and 405
-Alex
Burning Brakes
Joined: Feb 2006
Posts: 1,085
Likes: 3
From: Ottawa Ontario, Canada
What's happening when cornering is oil gets into the outboard side cylinder head and doesn't drain back down to the oil pan until the car comes out of the corner (no more G's holding the oil up). If the corner is long enough the oil pan can go dry as the pump has put all of the engine's oil into service but none of it is returning to the pan.
As far as I know this happens on all LS engines. The dry sump system introduced on the LS7 was supposed to help with this, but I guess there are still issues?
Racer
Joined: Jan 2006
Posts: 399
Likes: 1
From: Jasper, GA
St. Jude Donor '10
Take a look at the C5 w/ the LS7 that Vengeance just posted and you be the judge. BTW, it drives just like Grandpa Ron shows, can raise H3!! on demand, and will have no problem with a future 100 shot. Yep, I love it. Hhmmmm . . . LS7 and the cubes was my choice. Look up Tim Lynch and I think you will see that an LS7 can hold up to about anything you throw at it. Thanks Ron, Mike, and Charlie!
Mike C
Mike C
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Safety Car
Joined: Oct 2004
Posts: 4,816
Likes: 132
From: Plano TX
Yep, If GM could have done a boosted motor with an L/S7, they would have done it in a heartbeat. Durability is the issue. LS1/and LS6 engines take forced induction fairly well, as compared to an LS7.. LS2 and LS3 are prefered overall by many builders. You can melt any motor with Forced induction.. The LS7 with very high compression and thinner cylinder walls is just an accident waiting to happen.. Maybe with a conservative tune and low boost (5-6psi) it might be ok for a long time.. Maybe is the key word. Thin is a bad word
Last edited by David426; Sep 20, 2011 at 09:39 PM.
Melting Slicks
Joined: Nov 2009
Posts: 2,536
Likes: 15
FWIW...Pratt and Miller offers a LS7 with a LS9 top end...meaning a "GM" LS7 short block (stock) except they change the pistons to Diamond, teflon coated, forged aluminum, ceramic topped and dished top with an FI ring package (from 11.6 to 9.1). But aside from the piston change all rotating assembly is stock.
Then they bolt on the LS9 cylinder heads and the factory Eaton blower. Upgraded injectors to 65lb'ers and spin it to the factory 10 psi (same as the ZR1).
Are you ready......drum roll.....760 HP and 830lb-ft on pump gas.
And my final thought is if Pratt and Miller is willing to build it and stand behind it then its good enough for me.
Thanks.....and for the love of God..please don't ask who P & M is !!
Then they bolt on the LS9 cylinder heads and the factory Eaton blower. Upgraded injectors to 65lb'ers and spin it to the factory 10 psi (same as the ZR1).
Are you ready......drum roll.....760 HP and 830lb-ft on pump gas.
And my final thought is if Pratt and Miller is willing to build it and stand behind it then its good enough for me.
Thanks.....and for the love of God..please don't ask who P & M is !!
Last edited by LSOHOLIC; Sep 21, 2011 at 06:43 PM.
Instructor
Joined: Sep 2006
Posts: 159
Likes: 0
From: Rantoul IL
Yep, If GM could have done a boosted motor with an L/S7, they would have done it in a heartbeat. Durability is the issue. LS1/and LS6 engines take forced induction fairly well, as compared to an LS7.. LS2 and LS3 are prefered overall by many builders. You can melt any motor with Forced induction.. The LS7 with very high compression and thinner cylinder walls is just an accident waiting to happen.. Maybe with a conservative tune and low boost (5-6psi) it might be ok for a long time.. Maybe is the key word. Thin is a bad word
Melting Slicks
Joined: Nov 2009
Posts: 2,536
Likes: 15
FWIW...Pratt and Miller offers a LS7 with a LS9 top end...meaning a "GM" LS7 short block (stock) except they change the pistons to Diamond, teflon coated, forged aluminum, ceramic topped and dished top with an FI ring package (from 11.6 to 9.1). But aside from the piston change all rotating assembly is stock.
Then they bolt on the LS9 cylinder heads and the factory Eaton blower. Upgraded injectors to 65lb'ers and spin it to the factory 10 psi (same as the ZR1).
Are you ready......drum roll.....760 HP and 830lb-ft on pump gas.
And my final thought is if Pratt and Miller is willing to build it and stand behind it then its good enough for me.
Thanks.....and for the love of God..please don't ask who P & M is !!
Then they bolt on the LS9 cylinder heads and the factory Eaton blower. Upgraded injectors to 65lb'ers and spin it to the factory 10 psi (same as the ZR1).
Are you ready......drum roll.....760 HP and 830lb-ft on pump gas.
And my final thought is if Pratt and Miller is willing to build it and stand behind it then its good enough for me.
Thanks.....and for the love of God..please don't ask who P & M is !!
For those interested in specs....they refer to it as a C6RS. Which is avaliable with a supercharged 7.0 (Brian Thomson built who by the way owns Thomson Automotive and does lots of development work on engine blocks for GM) or the Katech N/A 500ci monster.
Thanks...
Race Director
Joined: Jul 2007
Posts: 11,467
Likes: 8
From: 972 and 405
So to be clear. It is your belief, that GM made the LS1 and LS6 engines more durable than the LS7, with LS2 and LS3 engines being "preferred". So for whatever reason, GM completely failed with the durability of the LS7, using no lessens learned from the previous LS engines, but finally recovered with the LS9.
-Alex
Thread Starter
Intermediate
Joined: May 2011
Posts: 28
Likes: 0
From: Texarkana TX
Finally got to break down engine. Found two cracks in block on #7 cylinder and the sleeve was pushed up slightly out of the block. I originally started this thread to see about the better ls series block for durability. Looking for 500+hp, NA. I car nothing about adding FI to build. I'm still leaning to a forged ls6 383 but having second thoughts after finding issue with block.
Any thoughts/comments?
Any thoughts/comments?
Race Director
Joined: Jul 2007
Posts: 11,467
Likes: 8
From: 972 and 405
Finally got to break down engine. Found two cracks in block on #7 cylinder and the sleeve was pushed up slightly out of the block. I originally started this thread to see about the better ls series block for durability. Looking for 500+hp, NA. I car nothing about adding FI to build. I'm still leaning to a forged ls6 383 but having second thoughts after finding issue with block.
Any thoughts/comments?
Any thoughts/comments?
-Alex
Thread Starter
Intermediate
Joined: May 2011
Posts: 28
Likes: 0
From: Texarkana TX
Wished I new. My first guess is bad tune or 2nd maybe the stock pistons could not hold up to the mods, 550hp at crank. I bought the car with mods. Car came from Ft. Meyers FL. I do not know who performed the work. I do plan to have LG Motorsports to dyno tune after new build. Also, mods include 42 lb injectors, forgot to add.
Instructor
Joined: Sep 2006
Posts: 159
Likes: 0
From: Rantoul IL
You tell me. Why do all the vendors sell FI kits for LS7s? Why are reputable shops installing the kits on LS7s? Where are the horror stories?
Instructor
Joined: Sep 2006
Posts: 159
Likes: 0
From: Rantoul IL
Based on your response, it sounds like you are not familiar with #7 cylinder failures. Do some searching, the topic goes back many years.
Race Director
Joined: Jul 2007
Posts: 11,467
Likes: 8
From: 972 and 405
Because you can sell parts won't break a car.
Are these same shops telling customer they can safely run as much boost as an LS3?
Why are you not answering the question directly?
Seriously I mean if you have a good point to make just share it instead of beating around the bush. We are here to learn not guess. Well the rest of us are.
-Alex
Are these same shops telling customer they can safely run as much boost as an LS3?
Why are you not answering the question directly?
Seriously I mean if you have a good point to make just share it instead of beating around the bush. We are here to learn not guess. Well the rest of us are.
-Alex
Instructor
Joined: Sep 2006
Posts: 159
Likes: 0
From: Rantoul IL
You are here to learn, huh? On an internet forum? If a professional opinion is what you desire, then why don't you do yourself a favor, and pick up the phone. Talk to the experts at A&A, LG, England Green, ECS, etc. That does not mean post within this forum, and make a shout out for them to reply. It means you actually and actively pursue the knowledge you desire. Are you willing to do that, or would you rather just repeat what you think is true, from this forum, LS1Tech, etc?