Ls2 N/A rebuild opinions/ thoughts
01-07-2016, 10:53 AM
#1
Ls2 N/A rebuild opinions/ thoughts Old setup
Hello everyone. Recently I pulled the old tired lq4 out of my 06 M6 GTO. I was running stock L92 heads on it with a BTR stage 3 LS3 n/a cam, full bolt ons, and fast 102 lsxr manifold. The old LQ4 ran good for what it was( tired old truck motor) but I wasn't satisfied with the power it made (385rwhp 342rwtq) and extremely low compression ratio. Nor was I happy about the weight penalty in an already heavy gto.
I ended up scoring a decent shape LS2 block out of a 05 gto that had spun a rod bearing. The block is at the machine shop right now getting cleaned up. I have LS3 take out rods in great shape with new arp rod bolts that I plan on reusing with this motor as well as a used 24x crank that I plan on getting polished. I plan on reusing the cam and other bolt ons and sticking with the L92 heads.
But my question is that I'm thinking of going with the wiseco K0044X05 domed 9cc Pistons with valve reliefs for stock rods stock stroke. With a 68cc head wiseco says it will give me 11.3:1 compression. Do you think my setup will be able to see 450-480rwhp? I want the most I can squeeze out of this setup with out going to a 402 as that's out of the budget this year. So do I have a good recipe for a strong running stock displacement n/a 6.0 or should I try and change anything? Thanks for all your input I appreciate it.
Hello everyone. Recently I pulled the old tired lq4 out of my 06 M6 GTO. I was running stock L92 heads on it with a BTR stage 3 LS3 n/a cam, full bolt ons, and fast 102 lsxr manifold. The old LQ4 ran good for what it was( tired old truck motor) but I wasn't satisfied with the power it made (385rwhp 342rwtq) and extremely low compression ratio. Nor was I happy about the weight penalty in an already heavy gto.
I ended up scoring a decent shape LS2 block out of a 05 gto that had spun a rod bearing. The block is at the machine shop right now getting cleaned up. I have LS3 take out rods in great shape with new arp rod bolts that I plan on reusing with this motor as well as a used 24x crank that I plan on getting polished. I plan on reusing the cam and other bolt ons and sticking with the L92 heads.
But my question is that I'm thinking of going with the wiseco K0044X05 domed 9cc Pistons with valve reliefs for stock rods stock stroke. With a 68cc head wiseco says it will give me 11.3:1 compression. Do you think my setup will be able to see 450-480rwhp? I want the most I can squeeze out of this setup with out going to a 402 as that's out of the budget this year. So do I have a good recipe for a strong running stock displacement n/a 6.0 or should I try and change anything? Thanks for all your input I appreciate it.
01-07-2016, 11:09 AM
#2
.....But my question is that I'm thinking of going with the wiseco K0044X05 domed 9cc Pistons with valve reliefs for stock rods stock stroke. With a 68cc head wiseco says it will give me 11.3:1 compression. Do you think my setup will be able to see 450-480rwhp? I want the most I can squeeze out of this setup with out going to a 402 as that's out of the budget this year. So do I have a good recipe for a strong running stock displacement n/a 6.0 or should I try and change anything? Thanks for all your input I appreciate it.
Also....I see no reason why that setup wouldn't get to about the 450HP range....can't see it getting much more than that, though.
KW
01-07-2016, 11:29 AM
#5
TECH Fanatic
With a stock LS3 topend milled .030" and a 227/235 Lunati cam, I put down 470/410 on a Dynojet through 3.73s in my GTO.
If you mill the heads or go with a thinner gasket, I would dial back on the dome size of the piston.
If you mill the heads or go with a thinner gasket, I would dial back on the dome size of the piston.
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01-07-2016, 02:21 PM
#9
With the block at the machine shop, why would you use a thinner head gasket? They can cut the deck to get the piston out of the hole as far as you want to get whatever quench you want with the cheap GM MLS gaskets.
Double check the compression ratio numbers in a calculator. I'm seeing closer to 12:1 with a 6.0L head gasket and the piston .010 out of the hole.
Double check the compression ratio numbers in a calculator. I'm seeing closer to 12:1 with a 6.0L head gasket and the piston .010 out of the hole.
01-07-2016, 02:35 PM
#10
TECH Fanatic
With the block at the machine shop, why would you use a thinner head gasket? They can cut the deck to get the piston out of the hole as far as you want to get whatever quench you want with the cheap GM MLS gaskets.
Double check the compression ratio numbers in a calculator. I'm seeing closer to 12:1 with a 6.0L head gasket and the piston .010 out of the hole.
Double check the compression ratio numbers in a calculator. I'm seeing closer to 12:1 with a 6.0L head gasket and the piston .010 out of the hole.
01-07-2016, 03:01 PM
#11
If he builds a 402, then it would probably be better to discard cheap GM gaskets than a set of .040" Cometic gaskets.
01-08-2016, 07:10 AM
#12
The pistons are 1.311" CH, so with stock 6.098" rods and stock 3.622" stroke, you're looking at a deck height of 9.220" which puts the pistons .020" in the hole, so it needs to be decked anyways. If he builds a 402, then it would probably be better to discard cheap GM gaskets than a set of .040" Cometic gaskets.
Ok educate me with this, sorry if I sound like a total idiot lol. I'd rather not have to do a stroker at all honestly. So with these junkyard dog Pistons, to achieve the 11.2:1 compression wiseco lists in the catalog with a 68cc head Id have to deck the block? Sorry this is my first full tear down of one. I was under the assumption that these Pistons were drop in's.
01-08-2016, 07:40 AM
#13
Ok educate me with this, sorry if I sound like a total idiot lol. I'd rather not have to do a stroker at all honestly. So with these junkyard dog Pistons, to achieve the 11.2:1 compression wiseco lists in the catalog with a 68cc head Id have to deck the block? Sorry this is my first full tear down of one. I was under the assumption that these Pistons were drop in's.
I don't know why Wiseco lists 11.2:1. Using an online calculator I get closer to 12:1 with a 4.050" x .052" 6.0l head gasket and the piston .010" out of the hole. Maybe they calculate it with the piston in the hole.
The LS2 blocks have a 9.240" deck height. At TDC, the piston will be in the hole about .020". With an .040" gasket, you're still looking at about .060" quench when .035-.040" is ideal. That's why I would recommend cutting the deck so that the piston is out .010" or so and using $30 head gaskets to get about .040" quench or less.
01-08-2016, 05:17 PM
#18
That's what I'm wondering. Wiseco's site list all their specs and compression on this chart showing .020 in the hole with a 9cc dome.
Attachment 523992
Attachment 523992
Question Justin....does the Wiseco chart state what type of head gasket (compressed thickness) they use to arrive at the stated compression ratio?
KW
EDIT: Just looked at the chart again.....they use a .051" gasket......... I think I'd go with another piston.......a flat-top with valve reliefs.
01-10-2016, 12:49 PM
#19
This part number piston is not a drop in. K0044X05 is for a 4.005" bore so the cylinders need to be honed. K0044XS is for a 4.00" bore and is probably the "drop in" piston you're thinking off. I don't know why Wiseco lists 11.2:1. Using an online calculator I get closer to 12:1 with a 4.050" x .052" 6.0l head gasket and the piston .010" out of the hole. Maybe they calculate it with the piston in the hole. The LS2 blocks have a 9.240" deck height. At TDC, the piston will be in the hole about .020". With an .040" gasket, you're still looking at about .060" quench when .035-.040" is ideal. That's why I would recommend cutting the deck so that the piston is out .010" or so and using $30 head gaskets to get about .040" quench or less.