Need help on a LQ4 build...
12-22-2011, 08:39 AM
#1
Need help on a LQ4 build... I've done some searching but can't come up with anything solid... I'm having trouble deciding what to go with as far as pistons...
I've got a 1999 LQ4 shortblock. The engine was complete but had sat outside covered by a plastic tarp but got some junk down in the cylinders, may clean up tho. I'm gonna tear the short block down and have it dipped. I may possibly have to get the block bored over.
I'm planning on running the following... in a 2nd gen Firebird with a 4L80e
LS3 heads with patriot spings and LS3 intake manifold-cable tb
Custom spec Pat G cam around .600? lift (I had pm'd him a while back)
Long tube headers and true duals
Custom tune
Decent convertor
As far as pistons go, what should I go with? I've read that the stock LQ9 should be fine as far as PTV with the lift I'll be around. With me having to possibly bore the block, what pistons should I go with? I'll more than likely be using the stock rods and crank.
If the short block turns out to be fine using the stock dished pistons, what kind of power could I expect using that setup with the lower compression ratio?
Any help will be greatly appreciated
Thanks,
Eric
I've got a 1999 LQ4 shortblock. The engine was complete but had sat outside covered by a plastic tarp but got some junk down in the cylinders, may clean up tho. I'm gonna tear the short block down and have it dipped. I may possibly have to get the block bored over.
I'm planning on running the following... in a 2nd gen Firebird with a 4L80e
LS3 heads with patriot spings and LS3 intake manifold-cable tb
Custom spec Pat G cam around .600? lift (I had pm'd him a while back)
Long tube headers and true duals
Custom tune
Decent convertor
As far as pistons go, what should I go with? I've read that the stock LQ9 should be fine as far as PTV with the lift I'll be around. With me having to possibly bore the block, what pistons should I go with? I'll more than likely be using the stock rods and crank.
If the short block turns out to be fine using the stock dished pistons, what kind of power could I expect using that setup with the lower compression ratio?
Any help will be greatly appreciated
Thanks,
Eric
12-22-2011, 11:37 AM
#2
I would personally suggest taking it .030" over, and upgrading to a 6.125" rod as well.
We have many options as far as 4.030" pistons and 6.125" rod combos in stock. Give us a call or shoot me a pm if you are interested.
We have many options as far as 4.030" pistons and 6.125" rod combos in stock. Give us a call or shoot me a pm if you are interested.
__________________
NOW OFFERING TSP BY YANK CONVERTERS
COMP - FAST - PACESETTER - WISECO PISTONS - LUNATI - CALLIES - NEW TSP BRAND CRANK & RODS - COMETIC GASKETS
RAM CLUTCHES - MOSER ENGINEERING - ARH HEADERS - ARP - GM BOLTS AND GASKETS - MSD - NGK
POWERBOND - ASP - PRECISION INDUSTRIES - YANK - CIRCLE D - AND MORE!
COMP - FAST - PACESETTER - WISECO PISTONS - LUNATI - CALLIES - NEW TSP BRAND CRANK & RODS - COMETIC GASKETS
RAM CLUTCHES - MOSER ENGINEERING - ARH HEADERS - ARP - GM BOLTS AND GASKETS - MSD - NGK
POWERBOND - ASP - PRECISION INDUSTRIES - YANK - CIRCLE D - AND MORE!
NEW NUMBER (512)863-0900
12-22-2011, 11:48 AM
#3
TECH Resident
The jumbo valves on the LS3 heads have a notable impact on PTV clearance but you may have known that already and I know Pat does. On a custom cam, Pat can take your Intake Valve Close into consideration where it will help out your compression if needed. If you have to get different pistons I think it would be ideal to get flat tops with valve reliefs. It seems that you would have the best of both worlds...compression with PTV clearance. On a stock motor the stock dished piston vs. the flat top is worth .4 in compression.
Here are a couple calculators that might come in handy for you...
http://www.csgnetwork.com/compcalc.html
http://www.wallaceracing.com/dynamic-cr.php
Here are a couple calculators that might come in handy for you...
http://www.csgnetwork.com/compcalc.html
http://www.wallaceracing.com/dynamic-cr.php
