INTERNAL ENGINE MODIFICATIONS Valvetrain |Heads | Strokers | Design | Assembly

new set up for the 408 opinions need

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Old Jan 7, 2008 | 09:08 PM
  #11  
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What are your ultimate power goals with boost? How much drivability off boost are you willing to sacrifice to gain power on boost? Is this a daily driver?
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Old Jan 7, 2008 | 09:21 PM
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i was thinkin about 10lbs to 15 lbs of boost maybe plus the nitrous.... AND yes this will be my daily driver... And it will see a share of track dayz as well.. UNLESS IT WOULD BE BETTER TO JUST DO A FULL NITROUS 408
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Old Jan 7, 2008 | 09:26 PM
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15psi should do ~700hp. I'd put the compression at 9.5. I would buy a methanol kit before n20. Start with a small cam like the one you already have. Then 9" or 14 bolt and 80e.
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Old Jan 7, 2008 | 09:38 PM
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how bout the nitrous.. SHould i diss the nitrous once i get the F/I? I thought i would need a sort of F/I to run meth or am i wrong?
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Old Jan 7, 2008 | 10:19 PM
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Buy the methanol kit once you add boost. At that point you can decide if you still need n20 on top of what you have.
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Old Jan 7, 2008 | 10:21 PM
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but i aint going to have boost till mid summer so until then im going to use nitrous..,...
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Old Jan 7, 2008 | 10:21 PM
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Originally Posted by Stoichiometric
15psi should do ~700hp. I'd put the compression at 9.5. I would buy a methanol kit before n20. Start with a small cam like the one you already have. Then 9" or 14 bolt and 80e.
This is what I would advise as well. My engine is about 9.4:1, and I'm running 15 psi with methanol and about 17 degrees of timing with no problems. That setup put my big heavy 4x4 with 33" tires into the mid 11's. My cam is a 220/222-580/580-114.

Originally Posted by xdanny510x
but i aint going to have boost till mid summer so until then im going to use nitrous..,...
Build it for FI, not nitrous.
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Old Jan 9, 2008 | 07:20 PM
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Keep in mind boost is a relative number. It is essentailly the positive pressure in the intake. You can make 30 psi with a small intake, baby cam, and stock exhaust. Shoot for a power level. I want to make XXX rwhp XXX rwtq and I want to run XX.XX et in the 1/4. That is where you need to start.

Example: Stock truck with a Radix 2.8 pulley making 12psi = 425 rwhp

CAI, GT 2-3 Linginfelter Cam, true dual 3" exhuast with longtubes making 8 psi = 500 rwhp

It is all about moving air in and out of the motor as efficiently as you can. Also being able to supply enough fuel for the air you put in it.

I agree with Stoich, 9.5:1 CR at 15 psi assuming all supporting mods are done, should get you around 700 rwhp.
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Old Jan 10, 2008 | 12:11 AM
  #19  
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after readin through atricles here and on ls1 tech.. im going to build the motor for H/C and be built for nitrous......
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Old Jan 10, 2008 | 07:10 AM
  #20  
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N2O motors loooove compression. If you are sure you are going for a nitrous motor, aim for 11:1, but keep in mind that doing so means you will NOT be able to boost it down the road.

If you think you might want to boost it still (you seem pretty undecided), 9.5:1 is good compression ratio that would allow you to run a ton and a half of N2O, and down the road switch to a mild boost setup (15psi or so).

Having said all this, the big power lives in a turbo. Having said that, the current fastest GM truck is an N2O motor (but in fairness, Parish held that title for a long time and Blacksheep edged him out while he was having some fuel delivery troubles).

Just make sure you are good with only having all that power when the bottle is full and hot
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