Motor build question
06-13-2016, 10:27 PM
#1
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Motor build question So I am building my LS1. I have done tons of reading. I plan on going turbo, because race car. I already know I need to go forged pistons and rods. I also am getting arp main studs and head studs. But now let's get to my question. I have stock 806 heads. From what I read if port and polished it wouldn't be worth going 243 heads. Can someone clear that up for me. Also any recommendations on forged Pistons and rods. I was thinking wiseco forged pistons and eagle rods. Also another question do I keep stock crank or go forged? And what cam do you guys recommend. My goal is 700 whp. Thanks guys. Also the turbo will be a T76.
06-14-2016, 06:45 AM
#3
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Stock LS1 pistons/rods have been 800+whp, and they're probably the weakest of the stock rotating assemblies. Literally ANY forged rod/pistons combo is strong enough to make all of the power you need with.
The 1998 block is notorious for cracking sleeves with lots of boost/heat.
The 1998 block is notorious for cracking sleeves with lots of boost/heat.
06-14-2016, 07:13 AM
#4
Personally, I don't like putting that much power the the aluminum blocks, especially an old LS1 block. The cylinders/sleeves are not that rigid so you tend to have some excessive blowby with that kind of power. People still do it and end up going fast though.
The 806 heads are not that great, and on an engine like this, probably aren't even worth porting. The 243 heads are good, but again, on an engine like this are probably not worth the expense. The heads I would want to run are the 317 castings. You get the better ports like what's in the 243/799 castings, but you also get a bigger 71cc chamber. This will let you run a lower boost-friendly compression ratio without having to use a dished piston.
As for pistons, Wiseco would be a good choice. If you were to find a set of 317 heads, you can use the 3.2cc flat top piston and end up with about 9.5:1 compression. A flat top is nice to use since the piston will be thicker versus a dished piston. It wouldn't be a bad idea to upgrade the wrist pins to a heavy wall either.
Eagle rods aren't all that bad, but I would prefer Scat H Beams for the money. The machine work seems to be a little better with Scat and I've seen their $300 I Beams look almost new after suffering the abuse of a 900whp turbo combo. Just be sure to have your machinist open up the pin bores on the rods and pistons a little bit. The pin clearance is a little tight for that much power, so opening them up will help keep them from seizing.
Hang these rods and pistons on the stock crank and they should handle a well tuned 700whp combo pretty reliably.
The 806 heads are not that great, and on an engine like this, probably aren't even worth porting. The 243 heads are good, but again, on an engine like this are probably not worth the expense. The heads I would want to run are the 317 castings. You get the better ports like what's in the 243/799 castings, but you also get a bigger 71cc chamber. This will let you run a lower boost-friendly compression ratio without having to use a dished piston.
As for pistons, Wiseco would be a good choice. If you were to find a set of 317 heads, you can use the 3.2cc flat top piston and end up with about 9.5:1 compression. A flat top is nice to use since the piston will be thicker versus a dished piston. It wouldn't be a bad idea to upgrade the wrist pins to a heavy wall either.
Eagle rods aren't all that bad, but I would prefer Scat H Beams for the money. The machine work seems to be a little better with Scat and I've seen their $300 I Beams look almost new after suffering the abuse of a 900whp turbo combo. Just be sure to have your machinist open up the pin bores on the rods and pistons a little bit. The pin clearance is a little tight for that much power, so opening them up will help keep them from seizing.
Hang these rods and pistons on the stock crank and they should handle a well tuned 700whp combo pretty reliably.