Calling all LS2 Experts
Thread Starter
Racer
Joined: Jan 2006
Posts: 409
Likes: 1
From: Charlotte NC
Drifting
Joined: Jul 2005
Posts: 1,533
Likes: 0
From: az
bob, any possibility of getting the stock tune put back on your car to see what happens? is it possible the tuner was looking for some unreal hp/tq gain (by adding too much timing) from his tune in exchange for some free words of month advertizement from you? looking at your dyno pull you can tell pcm pulled some timing at 3100rmp. perhaps another option is to data log your car and see if there is any KR.
Thread Starter
Racer
Joined: Jan 2006
Posts: 409
Likes: 1
From: Charlotte NC
bob, any possibility of getting the stock tune put back on your car to see what happens? is it possible the tuner was looking for some unreal hp/tq gain (by adding too much timing) from his tune in exchange for some free words of month advertizement from you? looking at your dyno pull you can tell pcm pulled some timing at 3100rmp. perhaps another option is to data log your car and see if there is any KR.
Melting Slicks
Joined: Oct 2006
Posts: 2,905
Likes: 1
bob, any possibility of getting the stock tune put back on your car to see what happens? is it possible the tuner was looking for some unreal hp/tq gain (by adding too much timing) from his tune in exchange for some free words of month advertizement from you? looking at your dyno pull you can tell pcm pulled some timing at 3100rmp. perhaps another option is to data log your car and see if there is any KR.
Drifting
Joined: Jul 2005
Posts: 1,533
Likes: 0
From: az
bob, do you have the lastest dyno any where for others to look at? do you know the ect, oil temp & iat # during the dyno pull? considering your car was your tuner's first ls2 vette maybe there was some heat soak issue on the dyno pulls? of course i am assuming 799 heads isn't an issue since siver05gto got 341hp stock, and with only halltech intake he got 345hp (799 heads).
Last edited by cbrf4i1; Mar 22, 2007 at 10:39 AM.
Drifting
Joined: Jul 2005
Posts: 1,533
Likes: 0
From: az
Do you guys think it's a possibility that since he has the 799 heads fron the LS6 that he also has the LS6 intake and that's whats hold the numbers back? The LS2 is similar, but a little more high flowing . Just wondering. I think he's alot closer to where he should be in dyno numbers than what he was, but I understand his frustration.Keep us tuned in, Bob.
Drifting
Joined: Feb 2001
Posts: 1,539
Likes: 63
From: new ulm mn
Checked mine this AM. Build date 10-13-06 with 243 heads. Funny how cars built before and after mine have 799 heads. Must be the luck of the draw as to which block they pulled off the shelf. I'm guessing the difference between the two is minimal. That being said, I'd be wondering if I had the 799 head.
Last edited by loflite; Mar 22, 2007 at 11:56 AM.
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Burning Brakes
Joined: Jan 2007
Posts: 968
Likes: 122
From: Lighthouse Point FL
Wait, you are citing an ad on Flea bay as proof that a 799 casting is the same as a 243. That's nuts. The ad also referrs to heads being off a 2005. I hope they did not stick on some "old" heads they had laying around on my '07.
I have yet to see an official part number related to the 799 casting.
On the GM Performance site they list different part numbers for the LS6 (12564825) and LS2 (12570245) cylinder heads. The compression ratio is also listed as different between the LS2 and LS6. 10.9:1 vs 10.5:1. I don't know if the difference is in the piston or the chamber...
Melting Slicks
Joined: Oct 2006
Posts: 2,905
Likes: 1
Hey, get this: According to HP Chevy LS1/LS6 V8 book, the casting number for LS6 01-04 heads end in .....243. Maybe Bob and the other 799'ers have something new, like when they put LS6 blocks in the LS1 birds and camaros in 2000.
Melting Slicks
Joined: Oct 2006
Posts: 2,905
Likes: 1
Racer
Joined: Mar 2006
Posts: 324
Likes: 0
From: Kalispell Montana
a few pictures below. apparently they are ls6 pre-production heads also.
pictures courtesy of Andrew on LS1Tech
pictures courtesy of Andrew on LS1Tech
Instructor
Joined: Dec 2006
Posts: 179
Likes: 2
From: Bloomer WI
This is what I have found out, 799 and 243 are casting numbers. These casting can be used prior to CNC to build different part numbers. The part number is the key not casting. OK 799 maybe mexicon sand cast, 243 is canada proform. Doesn't really matter until the CNC makes them into the part number GM wants. CNC will make a 799 or 243 the same. What I have found out from my buddies at GM is the correct part number for the ls2 vett is 12564825. I did see someone else list something else. In regards to HP on a stock LS2 vett, 400 hp X 15% drive train loss is 340 RWHP. Seems to match to me. This has been fun doing the research.
Instructor
Joined: Apr 2005
Posts: 152
Likes: 0
From: Charlotte North Carolina
It Would Not Be Happy
I have a 2005 Z51 6 speed. It is equiped with Callaway Honker CAI, LG longtubes and Borla sport exhaust. Jeff Creech at Carolina Auto Masters tuned my car over a year ago and it made 400 rwhp unadjusted (it was a cool night). SAE adjusted it made about 386 rwhp and 383 fpt. I specifically asked for a conservative tune because I don't track the car very often and never drag race. The car has never had any problem from Jeff's tune, it runs great and never throws codes.
Instructor
Joined: Dec 2006
Posts: 179
Likes: 2
From: Bloomer WI
Oh yeah one other thing. My part buddy at GM says to look for the actual part number stamped on the side of the head. On the passenger side that would be facing the firewall, drivers side in front but covered by the power steering pump. I will be looking for mine with a mirror when I get off work. I am keeping my fingers cross that I do have the right part numbers.
Racer
Joined: Jan 2007
Posts: 260
Likes: 1
From: Central FL
Question now is, where the heck did GM find pre-production LS6 heads 2-3 years after the production 243's had already been out, and why stick them in a limited # of 2007 Corvettes??
If they flow the same I'm gonna tout my car as an ultra rare factory 799 vette.......easily worth more then the cookie cutter LS2 w/243 heads
If they flow the same I'm gonna tout my car as an ultra rare factory 799 vette.......easily worth more then the cookie cutter LS2 w/243 heads
But also note that this just created what will be a huge PITA in 25 years with the NCRS. Most folks stating 799 have 10/06 build dates but apparently not all 10/06 cars were equipped with the 799, some had the 243. Then there is this one reported 12/06 with the 799.
As for the original cause for this thread, lower than expected dyno results, I am worthless to you in that arena. I have a 100% stock '05 (MN6 & F55) with 243. If someone in the Orlando, FL area with a stock 799 wants to do a trip to the tuner/dyno at the same time let me know.
Burning Brakes
Joined: Sep 2004
Posts: 815
Likes: 76
From: Lincoln CA
St. Jude Donor '16-'17,'19
Here's an interesting case. I have a 10/30/2006 build date ...and one of each head. The passenger-side casting is a 243 and the driver's-side (viewable just underneath and behind the alternator) is a 799. Obviously, I'm hoping that the CNC-finished heads are determined to be the same part.
-Ernie
-Ernie
Instructor
Joined: Dec 2006
Posts: 179
Likes: 2
From: Bloomer WI
Here's an interesting case. I have a 10/30/2006 build date ...and one of each head. The passenger-side casting is a 243 and the driver's-side (viewable just underneath and behind the alternator) is a 799. Obviously, I'm hoping that the CNC-finished heads are determined to be the same part.
-Ernie
OH NO A HYBRED...
-Ernie
OH NO A HYBRED...