LSupNorth6.0

Hey guys, I'm gonna test my theory but looking for some opinions. I just replaced my lm7 with the lq9 and I know my tune isn't perfect, I'm waiting for my new injectors to get a zippy tune. the lm7 has the old style pcv valve and my lq9 has the new style 04+. My tuner used an 03 SSS "base tune." So the question is with having the new style and tuned for old style would that cause a "vacuum leak"? The only issue I have with the tune is that upon deceleration at lower speed, to stop lights and such, I get some rpm variation until I stop completely. Once in a while it will die if I stop too fast it seems. And my idle likes to go 750-800 when parked and its commanded 750. Could this pcv cause a leak that would do this? I occasionally get a MAF code as well, usually after it tries to die, I've watched the g's before and it does dip under 5-6 when trying to die. I know this could just be in my tuning but want to make sure I'm going to plug it off to the intake and see if it helps at all. I have a catch can setup if I need to install. Thanks in advance for any help

Welcome to the site from WI!

Welcome! I'm not too far south of you, haha, how's the weather?

mileage on them?

Thanks. I was wondering how people were doing it. Im lookin to do the nick Williams 102 with a fast 102 lsxrt 100 mm MAF and 8.1 marine injectors. Well and a new set of heads, haha!

Will the TB plug right in?

I have a magnaflow dual in/ dual out 2.5" too, I like the way it sounds but at 60 mph and around 1700-2000 in stall at take off it drones pretty decent. My exhaust is pacesetter LT's with 3" to x pipe muffler and 2.5 tails. On my old truck I had the sand headers with 2.5" true dual and individual magnaflows with 0 drone

I'm with blown 346, though other possibilities are intake vacuum leak, and as mentioned plugs/wires. Maybe even an injector..but more than likely just something stupid.

Welcome. Sounds like you have a pretty BA ride. Good luck with your turbo project, can't way to hear about the finished product

I should mention expected hp is what you should base your injectors off of, boost is a factor but doesn't exactly = hp.

Thats an awesome time for your mods! Nice. I'm sure others will chime in , but if you have the resources to cam it before, I certainly would. From what I've seen a good FI cam will be a mild one. Ls6 cam I've heard to be good, but in general something in the 220's and slightly more exhaust duration to help evacuate cylinders. Also I've seen most FI guys go with a little higher lsa such as 115 and above. I'm not familiar with SC'a as much as turbos but the injectors should be based on how much power your wanting to have along with how much boost it will be throwing down. How much boost will that 2.8 pulley put out? If you're expecting over 600 rwhp you may need those bigger injectors, though I'm not an expert with injectors. To make more power I would suggest a good set of heads with your cam setup. I'm pretty sure a proper head/cam setup on an lq9 will get you close to 475-500 rwhp alone. With good heads and cam you'd more than likely need the bigger injector size. On a side note I hear those new hurricane dispensers with built in tornado valve work awesome !! Lol

Oh for sure. I'm gonna wait for my zippy tune before showing off though haha!

Well it's all done now. Thanks for your help guys. It's running great besides needing some tuning.

Maybe they've been outsourcing the driveshafts to a person with vertigo Seriously though, maybe it's in the driveshaft itself, or the transfer case. I find the whole thing disappointing though.

Upon further investigation I have found its prolly in my best interest to switch to the 5.3 intake due to the fuel pump system not being the same with the regulator and all. Sorry for the pointless post.

Just noticed I have a different fuel rail from the lm7 to 6.0. My 6.0 stuff has less miles and I'd rather use it with no return, but does anyone know if it will effect my evap system to block it off?

Hey guys, my name is spencer. I hail from northcentral wisconsin. Figured i'd formerly introduce myself... I've owned chevy since I could first drive, 1997 Monte Carlo. Then stepped up to trucks. I always wanted an SS, but as a college student couldn't afford it. I graduate in about 6 months and just got everything I need to swap my LM7 Silvy to an LQ9. So far on previous trucks I've only gone as far as headers, CAI, stall, I'm pretty stoked to get some more actual HP! Hopefully doing the swap his weekend. Thanks for creating such a great environment for enthusiasts !

Those other posts have some good info. A guy brought his truck to our shop because he had a lowering kit installed and dealership told him the drive shaft angle or length with the lowering could be doing it. We didn't look into it really, but sounds like the same vibration, his was at about 25-35. If the dealership he talked to was right I would imagine there would be significant stress between the transfer case and rearend due to the driveshaft being pinched between, being that its only at certain speed I highly doubt it was his lowering kit and the length/angle. Sounds like an inherent problem. Hope you can get it squared away!

I guess I shouldn't have said the measurements are all over. The zero lash pushrod lengths I found were from 7.265-7.275. Which I believe is the difference between intake and exhaust lobes. Maybe not though. I found a lifter I didn't touch and tried pushing on it with no give. With 5 cylinders being between these measurements I assumed I'd be safe with the 7.350's. what did you find preload to be with proper swipe?

I have had pacestter's on three different trucks. Stock 5.3'a with tuning. On two of them, may have been a bad motor mount or two, but the passenger side primaries were nailing the frame I assume on first shift kick downs. The third set on my current truck clear he frame better but one of the primaries was built so close to my front diff knuckle the bolts hit with driveshaft installed when turning left only though. I must add they warranted one pair that got all rusty and then cracked from hitting frame( wisconsin). And they sent me a new one ho replace the one hitting my front diff knuckle. To me, it depends how much you wanna screw with it. If I was gonna spend a G I'd go with ARH. But given Ive owned three pairs of these I'm not that way. Plus it's a three inch collector on a pacesetter, and they have 1 3/4 for 400 or the 1 7/8 primaries for 500. Take my experience for what it's worth.. I'd buy them again, unless I struck it rich, then ARH.. For the record the sound really nice. I have dual 3" to 2.5" with magnaflow x-pipe muffler, no cats, I like the sound. But I paid less than 200 for all the pipe and bends and flanges, welded it myself and bam. Custom true dual with x pipe muffler. Sorry, looks like you decided already. Let us know how you like em!

I did soak the lifters and poured oil down the bores. I let the lifters soak and moved them around to different positions until they stopped bubbling. It was probably a good 4 hours... With .075 preload it would appear as though I'd get a nice run pattern on the valve tip. (l l)

I have a set of comp 850 lifters. I am reading different measurements all over. I was planning on running .075. What is everyone else running?