how much boost on stock lq9
#21
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There's really no way of knowing what boost is best or what is the most you can use. The best thing for you to do is look at some other builds to see what they have done . I have a 6.0 in my fairmont with a t4 s480 works great I boosted a 179,00 mile bone stock 6.0 with stock valve springs stock head gaskets everything with 20 psi for 5 months before I broke it and the only reason I blew a head gasket was a collapse flex bellow. So who knows. It all depends on luck a lot of times. Just research and try something you'll never learn anything If you don't learn from experience and get your hands dirty.
#22
Larger turbines mean more power from less back pressure and less pumping losses. This also means less heat. 18 psi can have a huge difference in power based on just temps because the hotter charge will contain less oxygen.
There are a TON of variables as to why a certain amount of boost doesn't mean a certain amount of power.
I've seen people run upwards of 30 psi on a stock bottom end and run 8.80s in the quarter. At the same time, stock48 is running 22 psi or so on a 76mm turbo and running in the low-mid 8s on a stock bottom end. There is no magic number.
There are a TON of variables as to why a certain amount of boost doesn't mean a certain amount of power.
I've seen people run upwards of 30 psi on a stock bottom end and run 8.80s in the quarter. At the same time, stock48 is running 22 psi or so on a 76mm turbo and running in the low-mid 8s on a stock bottom end. There is no magic number.
#23
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nice
thank you so much twin turbo for your input.. with the information you gave now i can find a comparable turbo to yours and "think" that i can use 15 psi and be a little on the safe side.. i dont mind at all learning and getting my hands dirty but i was just looking for a starting point.. thanks again
#24
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No problem at . Good luck with your build turbo stuff is simple nothing to it. I learned the hard way before turbo stuff was cool.Lol! S480 or 475 will work great especially if you do a nice converter and custom camshaft. And keep it at 10 to 15 psi and the timing low you'll be good .
#25
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your not getting what he is saying. the question you should be asking is how much power will a stock lq9 handle. not how much psi it can handle. being STOCK everything, it will still vary from engine to engine. PSI has nothing to do with engine reliability. it all comes down to horsepower. if u only want to make 600whp, throw whatever psi it takes to get it there and itll be fine, regardless if its 5psi or 15psi.
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We can go back and forth and and say it'll handle this hp and this boost but your right it's different from motor to motor . Just boost it and have fun You'll eventually tear it up or have a problem it's just part of the game.
#27
You're drastically overthinking what he asked!
You're not getting the point. Boost doesn't equal power. The stock block can handle 50 PSI as long as that doesn't equate to enough power to break the rods. Boost has nothing to do with it. The block doesn't 'sense' that too much boost is being forced into it and decide to blow up. Its a combination of power/torque/rpm that causes them to give out (assuming detonation isn't the issue), and since boost doesn't equal any of these figures on any sort of linear scale, its completely irrelevant.
A tiny turbo forcing air through unported heads on a stock cam and intake with no intercooler might make 600 HP at 23 PSI and ~5600 rpm and the block live forever. Take the same bottom end, put on ported LS3 heads, a Holley Hi-Ram, a custom grind turbo cam, A2W Intercooler, methanol, and a large billet 88mm, and the bottom end blows apart at 18 PSI at 6400 RPM.
There are literally 50 people a week that ask this same question.
A tiny turbo forcing air through unported heads on a stock cam and intake with no intercooler might make 600 HP at 23 PSI and ~5600 rpm and the block live forever. Take the same bottom end, put on ported LS3 heads, a Holley Hi-Ram, a custom grind turbo cam, A2W Intercooler, methanol, and a large billet 88mm, and the bottom end blows apart at 18 PSI at 6400 RPM.
There are literally 50 people a week that ask this same question.