lq4 logical limit
05-08-2010, 01:52 PM
#1
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lq4 logical limit ive heard some amazing stories about lsx's and the amount of abuse they can take but i like to be a little more realistic. ive been working on a mental engine build for a few weeks now and i want to take an average lq4( 30-70,000 miles no more), stick in the orgasm stick 4 (MS4
) stock heads stock bottom and run it to 6800 redline quite frequently in a fairly light auto 96 impala ss. is this a safe redline? im worried im going to shoot me moneys out the sides of the block ive heard of arp rod bolts, is this cheap insurance or does it cost more than i want to spend? i plan on using ported ls6 oil pump just for safety. id like to sparingly use nitrous in the future. does this sound dangerous to anyone? please help im fresh on the nitty grittty with lsx and am starving for knowledge of every single aspect of this engine!!!
) stock heads stock bottom and run it to 6800 redline quite frequently in a fairly light auto 96 impala ss. is this a safe redline? im worried im going to shoot me moneys out the sides of the block ive heard of arp rod bolts, is this cheap insurance or does it cost more than i want to spend? i plan on using ported ls6 oil pump just for safety. id like to sparingly use nitrous in the future. does this sound dangerous to anyone? please help im fresh on the nitty grittty with lsx and am starving for knowledge of every single aspect of this engine!!! 
05-08-2010, 02:05 PM
#2
install good springs and push rods also.also install a new timing chain.arp rod bolts are a good idea if you can afford it.will you be milling the heads to raise compression?buy a cam kit from TSP ,and gaskets also.
05-08-2010, 02:20 PM
#3
You do realize that the compression of an lq4 is only 9.4:1 and combine that with a ms4 and you're looking at motor that will be lazy. An lq9 would be better but I would use an ls2 which would be optimal.
Now you are talking about putting it in an impala ss. What is your idea of light? If you pulled the interior and ac you are at the stock f-body weight which is not too light. You will need a big stall and gears. Check into the Katech rod bolts. They can be installed with out resizing the big end of the rod unlike the ARP rod bolts.
I would stroke a 6.0l and put it in that car. More cubes will help get that big tank off the line.
Now you are talking about putting it in an impala ss. What is your idea of light? If you pulled the interior and ac you are at the stock f-body weight which is not too light. You will need a big stall and gears. Check into the Katech rod bolts. They can be installed with out resizing the big end of the rod unlike the ARP rod bolts.
I would stroke a 6.0l and put it in that car. More cubes will help get that big tank off the line.
05-08-2010, 05:13 PM
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You do realize that the compression of an lq4 is only 9.4:1 and combine that with a ms4 and you're looking at motor that will be lazy. An lq9 would be better but I would use an ls2 which would be optimal.
Now you are talking about putting it in an impala ss. What is your idea of light? If you pulled the interior and ac you are at the stock f-body weight which is not too light. You will need a big stall and gears. Check into the Katech rod bolts. They can be installed with out resizing the big end of the rod unlike the ARP rod bolts.
I would stroke a 6.0l and put it in that car. More cubes will help get that big tank off the line.
Now you are talking about putting it in an impala ss. What is your idea of light? If you pulled the interior and ac you are at the stock f-body weight which is not too light. You will need a big stall and gears. Check into the Katech rod bolts. They can be installed with out resizing the big end of the rod unlike the ARP rod bolts.
I would stroke a 6.0l and put it in that car. More cubes will help get that big tank off the line.
05-09-2010, 08:22 PM
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i dont think i can mill the heads without ptv clearance issues but ive seen the ms4 make 380 to the wheel in a subaru wrx of all things with a stock long block lq4, truck intake, stock manifolds(truck ones?), i think a y pipe with custom single exhaust, m6, wrx irs, ms4, and about four runs of tuning it made 381 at the wheel i couldnt see what rpm's though. i think i read on here somewhere that static compression is around 10.1 w/ms4 which is still not the best. i looked at texas speeds numbers for an ls1 it seems to make power up to 6400 then drops a couple horse up to 6800.
im planning on mostly racing the car 3800 nitrous ready stall, 410's in the 10 bolt
im trying to get it down to around 36-3700 pounds roughly with my skinny 145 pound *** in it. i might try cleaning up the stock heads but not messing with anything major
does anyone have a rough estimate on rod bolt replacement? or can i do it myself with the Katech kit? im trying to do it on the cheaper side for what thats worth but if i could i wouldnt hesitate to put a 427 l92 in with a couple hairdryers!
im planning on mostly racing the car 3800 nitrous ready stall, 410's in the 10 bolt
im trying to get it down to around 36-3700 pounds roughly with my skinny 145 pound *** in it. i might try cleaning up the stock heads but not messing with anything major
does anyone have a rough estimate on rod bolt replacement? or can i do it myself with the Katech kit? im trying to do it on the cheaper side for what thats worth but if i could i wouldnt hesitate to put a 427 l92 in with a couple hairdryers!
05-09-2010, 09:24 PM
#6
The lq9 is 10:1 not the lq4. If that wrx made 380 to the wheels with a manual trans expect 340-350 with the same setup in a stalled auto.
3800 is not near enough to get some good 60ft from that tank. There are guys using 4000 in f-bodies. Plan on using something closer to that or bigger.
You can replace the rod bolts yourself and they are a lil more expensive than the ARP's. Bad idea on the l92's for forced induction. The heads have a thin deck which makes them prone to cracking and pushing water.
3800 is not near enough to get some good 60ft from that tank. There are guys using 4000 in f-bodies. Plan on using something closer to that or bigger.
You can replace the rod bolts yourself and they are a lil more expensive than the ARP's. Bad idea on the l92's for forced induction. The heads have a thin deck which makes them prone to cracking and pushing water.
05-09-2010, 11:32 PM
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damn i didnt know that about the l92's shows how little i know thanks for the tip. do think the 4000 stall would be nice on the street? i would only really take it to the local spot or downtown chi town (20+ miles from me). as far as the cam am i better off with something else? i liked the cam because of the strong upper end and the idle sounded not too bad it seemed to make the most out of the stock long block ls1 i figured it should do about the same maybe a little less with more cubes less compression. ive heard it loves nitrous which i plan to do much farther in the future, not before head milling and porting, flycuts on stock pistons or new forged, and fast intake, prolly a lot more stuff by then. in the mean time i just wanted a car that sounds wicked as hell and pulls like a beast up top(really looking forward to laying smack down on evos and the like) to make all my friends jealous
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05-10-2010, 08:59 AM
#9
You need a different cam. Are you using the stock truck intake? Are you using the stock truck exhaust manifolds? I think you would have a much better running car if you back that red line back down to 6,300 so you do not need to buy the rod bolts and get a cam that has better low end and mid range.
05-10-2010, 11:02 AM
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id really like to build around the cam if i can i took a ride in an A4 car with this cam and nitrous, Effing ***** out fast. id like to run the 243 casting to save some face and gain what little compression i can from that and give it all the supporting mods of course i.e. headers, ls6 intake, 85mm tb, injectors, and good tuning. id like to keep it on the cheaper side or else i would love to get some cubes out of this thing to bring the revs back down trying to use hp to propel me
05-10-2010, 11:12 AM
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LQ9 pistons on stock heads will get you up to 10:1. The LQ4 has a 70cc combustion chamber. Shrink that down to somewhere around 59-60 and you'll be in the 11:1 area. LS6 heads have a 63 or 64 cc chamber if I remember right. That'd get you around 10.5:1
05-10-2010, 11:17 AM
#12
id really like to build around the cam if i can i took a ride in an A4 car with this cam and nitrous, Effing ***** out fast. id like to run the 243 casting to save some face and gain what little compression i can from that and give it all the supporting mods of course i.e. headers, ls6 intake, 85mm tb, injectors, and good tuning. id like to keep it on the cheaper side or else i would love to get some cubes out of this thing to bring the revs back down trying to use hp to propel me
05-10-2010, 11:26 AM
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sorry sorry i meant the 241's i want to run, which i think still gives me 10:1 i would love ls6 heads just cant. not anytime soon 
maybe i can get real lucky and find some cheap ported 241's on here or craigslist chicago gets hot sometimes, but its a long shot prolly gonna get stockers maybe for free from my buddy they are sitting in his garage.
maybe i can get real lucky and find some cheap ported 241's on here or craigslist chicago gets hot sometimes, but its a long shot prolly gonna get stockers maybe for free from my buddy they are sitting in his garage.
05-10-2010, 04:53 PM
#14
The 317 head that comes on an lq4 or lq9 has a 76 cc chamber. It is essentially an ls6 head with a bigger chamber. Don't get another set of heads just mill those down, but not too much and you can get the compression up and turn them into an ls6 head at the same time.
If you are choosing that motor, you need to choose another cam. That cam has no bottom end torque and a Honda with vtec will beat you off the line. You have a car that is more than likely too heavy for that cam. I am not saying you can't use that cam, but you will need a big stall and gears because the cam has no bottom end torque. The polluter is supposed to be big just like the MS4 but have bottom end grunt to go with it, so you might want to look into that.
If you are choosing that motor, you need to choose another cam. That cam has no bottom end torque and a Honda with vtec will beat you off the line. You have a car that is more than likely too heavy for that cam. I am not saying you can't use that cam, but you will need a big stall and gears because the cam has no bottom end torque. The polluter is supposed to be big just like the MS4 but have bottom end grunt to go with it, so you might want to look into that.
