Generation IV Internal Engine - Need some advice for LS2 piston/rod for Nitrous




silvertl
06-13-2012, 05:17 PM
I have a LS2 that i'm going to put pistons and rods in. This V8 stuff is all new to me, I'm not expecting someone to hold my hand but help and advice. I've tried to search but couldn't find any good threads/forums about what piston/rods people have had luck with running nitrous on.

As for the Compression ratio I was thinking a 9.5 or 9.7 ratio for pistons? I will probably spray the car every now and then when i go to the track, but this car will be driven on the streets mostly.

I was currently running 7.4 comp push rods, Patriot valve springs/retainers, and LG motorsports G6X3 cam. I plan to run this same set-up on the heads.

Thanks in advance guys..


silvertl
06-14-2012, 03:46 PM
anyone?

Sales4@Texas-Speed
06-15-2012, 11:49 AM
We like to use Wiseco pistons with callies rods for the heavy power adder setups. The Wiseco pistons have a very thick crown and they all come with a steel top ring which can handle a lot of power adder if needed. The callies compstar h-beam rods have a pretty conservative rating of 900hp. How much nitrous are you trying to spray? I would try to get some more compression in the motor unless you plan on spraying a LOT of nitrous.


silvertl
06-15-2012, 04:18 PM
We like to use Wiseco pistons with callies rods for the heavy power adder setups. The Wiseco pistons have a very thick crown and they all come with a steel top ring which can handle a lot of power adder if needed. The callies compstar h-beam rods have a pretty conservative rating of 900hp. How much nitrous are you trying to spray? I would try to get some more compression in the motor unless you plan on spraying a LOT of nitrous.

I'm planning on running 150-200 shot of nitrous. I'm looking into which nitrous TB plate i will be running. Thank you for seriously giving me a start on advice. I've been trying to look for what a good CP ratio for pistons would be, and am having some difficulty. I'm use to motors with 4cylinders LOL. would a 10:5 or 10:7 be better compression on a 150-200 shot?

DirtyDirk
06-15-2012, 04:24 PM
I know the ls2 piston has a thin crown but wouldn't it be ok for a 150 shot?

Sales4@Texas-Speed
06-19-2012, 05:52 PM
The stock LS2 piston probably would take a 150 shot but we usually try not to go above that, just in case.

For compression ratio I would shoot for 11.0:1. That will leave you with a safe setup, but can handle that kind of nitrous no problem. Of course you want to make sure you are tuned correctly for the nitrous.

1nasty86
06-19-2012, 06:06 PM
I have a wiseco 4.005 piston and a scat 7/16 rod combo and its worked very well for me so far... All being under 1k for pistons, rings, pins, rods and arp rod bolts....

batboy
06-21-2012, 09:59 AM
Sounds like you've gotten good advice. I have no problem shooting for 11:1 CR for nitrous. Heck even more for a smaller shot. Forged pistions are critical, Wiseco like was mentioned or Diamond. The top ring should be steel and maybe consider gapping the rings a little wider than you would for N/A. Forged rods like Calles or Lunati with ARP rod bolts would also be good insurance.

silvertl
06-21-2012, 02:28 PM
Thanks for the advice guys. I pulled apart my bottom end. Had a spun rod bearing! So Forged internals are going in. I'm still trying to research and understand the +12cc or -4cc. I know it has to do with compression ratio.

From what i'm getting at so far, a -12cc piston with oem gasket is roughly 11:5 compression?

Sales4@Texas-Speed
06-22-2012, 11:40 AM
What heads will you be running? Unless the chamber is really small I would think a -12cc piston would drop the compression quite a bit. If I know the combustion chamber on the head I can show you which piston I would recommend for the right compression ratio.

batboy
06-22-2012, 06:18 PM
If this is a LS2 with 243 heads, your combustion chambers are about 64cc. Pistons with -12 dish will drop your CR down to about 9.75. Unless you plan on going turbo or supercharger, I'd get the -3 relief pistons and mill the heads 0.010" which should give you around 11 CR.

silvertl
06-23-2012, 10:50 PM
Yes ill be running 243 Heads. So im def going to want atleast a -3cc and UP piston, because i would like to raise the CP. The cam im running is pretty agressive, i plan on spraying it 150-200 shot. so i want a mid 11 or 12 Compression ratio...

silvertl
06-23-2012, 10:51 PM
JonJanz@Texas-speed, ill be ordering some parts from you within the next couple weeks or even sooner, after i get everything in order.

Sales4@Texas-Speed
06-25-2012, 07:48 PM
Yes ill be running 243 Heads. So im def going to want atleast a -3cc and UP piston, because i would like to raise the CP. The cam im running is pretty agressive, i plan on spraying it 150-200 shot. so i want a mid 11 or 12 Compression ratio...

Yes sir you will want to look at the Wiseco -3.2cc flat top piston. This will leave you with the correct compression ratio. You might need to mill the heads or go with a thinner gasket to get all they way where you want but that would be the way to go. Feel free to call or PM me if you have further questions!

2002TransAmKid09
06-26-2012, 10:33 AM
i know this is obvious but hasnt been said so just making sure he knows, your ignition timing needs to be retarded and colder plugs.. incase he wasnt sure but def man, Texas-Speed will hook you up. ALL of my parts come from them aside from my GMMG catback which was discontinued. also if your valve springs go out on you, look into some PRC's, chromoly push rods.. other than that the bottom end looks great with wiseco or diamond, and H beams, and ARP bolts