LQ9 with 243s
11-30-2015, 09:23 PM
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LQ9 with 243s
I have an LQ9 and a set of 243 heads. It's time to decide on exactly how much to mill the heads, what thickness head gaskets and decide on a cam (or have a pro spec one). The pistons are about .013" out of the hole, would that be a safe quench with .041" gaskets?
I'm not going to have any mods done on the heads aside from milling and I'm not going to have the slugs flycut. My fuel options are 93 octane pump gas or e85 pump gas (if beneficial).
As far as application goes, it's a mud truck that doesn't touch the street. It gets trailered to events, only a small handful a year. It's not and never will be competitive, just for slinging the s*** out of Ga clay for fun.
My goal? Build a stout running, nasty sounding LQ9 on a budget. I will choose a stall speed after the engine is built (th400 w/ rmvb). This will be injected via a stock LS1B PCM.
Finally my questions...
Do I make a decision on a cam and mill the heads based on the cam and PTV/ etc. Or, go after max CR with these heads/ Pistons and then choose a cam based on CR and PTV. Basically, the chicken or the egg?
Lmk if the truck specifics are important, I'm guess they're not since I'm not after an E.T. Or HP goal.
I'm not going to have any mods done on the heads aside from milling and I'm not going to have the slugs flycut. My fuel options are 93 octane pump gas or e85 pump gas (if beneficial).
As far as application goes, it's a mud truck that doesn't touch the street. It gets trailered to events, only a small handful a year. It's not and never will be competitive, just for slinging the s*** out of Ga clay for fun.
My goal? Build a stout running, nasty sounding LQ9 on a budget. I will choose a stall speed after the engine is built (th400 w/ rmvb). This will be injected via a stock LS1B PCM.
Finally my questions...
Do I make a decision on a cam and mill the heads based on the cam and PTV/ etc. Or, go after max CR with these heads/ Pistons and then choose a cam based on CR and PTV. Basically, the chicken or the egg?
Lmk if the truck specifics are important, I'm guess they're not since I'm not after an E.T. Or HP goal.
11-30-2015, 09:42 PM
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Regarding intake and exhaust, I'll tackle those accordingly once the engine is built so that the engine itself will no longer be a variable. I'll build the headers however compliments the engine combo but I'm dreading the intake because I really don't want to spend any money on one. Id rather just use my stock truck intake but will consider an aftermarket piece if necessary.
11-30-2015, 09:47 PM
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If you want any sort of power the truck will be a factor, you dont want something thats all top end if you're pushing 7000lbs.... As far as intake go with tbss or gen iv setup theyre cheap and flow good comparatively and they are a lot less expensive than a fast or holley...
11-30-2015, 10:13 PM
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Ok, it's a 94 Toyota Xtra cab with a beefed up frame, th400, np 205 transfer case (1-96:1 ratio in low range), 2.5 ton top loader axles (6.72-1 ratio) and 44" x 19.5 x 15 Super swamper Boggers that have every other lug cut out. Don't know how much it weighs but I'd guess it's > 6K#??
My thinking is that if most of the power is up top, I would just choose a stall speed accordingly. Is that the wrong mindset to have?
My thinking is that if most of the power is up top, I would just choose a stall speed accordingly. Is that the wrong mindset to have?
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12-01-2015, 06:18 AM
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This is pretty much all I do with this truck. This video was when it had 1 ton axles (5.13-1) a 5.3 and Maggie 112 @ 6#. I think it still had an 80e with stock converter at this point.
I guess I don't need the torque curve to be too high in the revs for the times I get stuck and have to get all 4 tires moving, buried in clay. So midrange?
Yessir the 112 is gone. I have an LQ4, L76 heads and an LSA blower w/ZL1 lid all on the shelf but that combo will go in my new truck build late in 2016. This LQ9 just needs to be a low budget combo to take the place of the 5.3/ 112 in my black truck. I'm keeping the black truck even once I build the new truck next year.
So I'll be ok to shoot for max CR via gaskets and mill and worry about the cam after?
Good to hear from ya Vortec! Your new build sounds badass!
12-01-2015, 06:21 AM
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As far as I know, regardless of where I want the power, compression is my friend so higher is exclusively better either way.?.?. I will choose a fuel accordingly.
12-01-2015, 06:28 AM
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Here's another video, the first shot is when the 80e broke the input sprag on the 1-2. That was straight off the trailer that day 
I figured out I still had 1st and 2nd if I shifted manual. The second shot was a timed run. I could see that working well with an all top end combo and a high stall. Get on the converter hard on the line then let it eat. Other times, like when I'm in deep mud, I guess low end would be beneficial. Does that mean a compromise of keeping the power at midrange makes the most sense?
I figured out I still had 1st and 2nd if I shifted manual. The second shot was a timed run. I could see that working well with an all top end combo and a high stall. Get on the converter hard on the line then let it eat. Other times, like when I'm in deep mud, I guess low end would be beneficial. Does that mean a compromise of keeping the power at midrange makes the most sense?