450whp DD is quite a bit to ask. I made 310whp on 91 octane, and still had issues with tuning/detonation. If you live somewhere you can get 110 octane fuel, a higher number might be more feasible, but in my opinion, 450 is a very, very high number. Also, is this still the stock b16? Your title said LS/VTEC. I'd assume you have a b18 bottom end.
First and foremost, do your research. Research parts, boost and how it works, requirements, maintenance on your car once it's boosted, life expectancy of your block (contrary to popular belief, if you're pushing out this much horsepower, your motor is going to eventually give out. Even if it's built. It's the nature of boost.) etc. Factor all that in, plus the cost of upkeep. Just from my expenses, the upkeep on my Turbo Integra was easily twice as much as all my N/A Hondas/Integras
With that in said, here's my $.02 in regards to recommendations for your build.:
• RC 750cc injectors
• AEM Fuel Rail (some guys will argue this. I suggest it. That much fuel saturating the rail = quick corrosion. An aftermarket aluminum fuel rail is not as susceptible to corrosion.) and Fuel Pressure Gauge.
• Pick up a GOOD name brand turbo (GReddy, Turbonetics, AIRresearch etc.). A t3/t4 or t27 is fine for your build. Try to get a turbo with a .57 or so AR trim. Your engine alone is going to break the 200hp mark if you built it properly, so spooling it won't be an issue. You'll be pushing that turbo to it's limit, so I'd recommend a staged rebuild kit (probably a stage 2).
• There is an argument as to whether 3 inch charge piping, or 2 inch is better. I used 2 inch, had virtually no turbo lag, and throttle response was great. But if you've got the money to build your engine enough, you can go with 3 inch. I'd consult whomever is going to tune your car, whenever you have your motor built on this one. Try to get custom piping, avoid having a ton of rubber connectors/elbows. Make as many pieces solid as possible.
• For your power goal (let's be realistic and say 350whp, and that's even a lot), you can go ramhorn, or topmount manifold. (expensive, but saves room). Make SURE you get a name-brand manifold. Do your research on this. You're going to spend $700+ on JUST your manifold, and Jesus Christ is it worth it. Don't be like me, get a middle-of-the-line manifold cause you're on a budget, and have your wastegate fall off on the freeway
• Wastegate options are plentiful. Go with name-brand, again. I had a Turbonetics Deltagate II. People hated on it, I loved it (I guess the spring gets stuck, so boost is constantly wide open. I disassembled mine, replaced the spring, cleaned the bladder/valve, and it was an amazing gate). I'd recommend a TiaL. Spring pressure is dependent on how much boost you want to go. They go by bar measurement (1 bar = roughly 21psi). 1 bar is probably fine.
• Buy a downpipe with a flexpipe that connects to your exhaust. If you don't, you WILL f**k your exhaust up.
• You want to go 3in on your exhaust. With a turbo setup, back pressure is not as important as an N/A vehicle. You want to get that stuff outta the car as quick as possible (for the most part).
• Your intercooler is completely up to you. Everyone rocks the front mount, because they're very effective. You can go top-mount, but it's a bit tougher to relocate some things. Go front-mount if you're in doubt. DON'T get a massive intercooler thinking you're all cool. Big intercooler = screwed up air/fuel ratio = detonation. A 3-4 row is plenty. Surprisingly, the eBay intercoolers are not too bad. Go with Spearco if you have the cash.
• Get a pre-tapped oil pan. DON'T tap it yourself unless you have someone with experience. The pre-tapped ones also have room for an extra quart or so of oil (yes, you're going to go through more oil, and faster.). Speaking of oil, ALWAYS full synthetic, ALWAYS change every 2k miles.
• Use A/N fitting steel braided lines for ALL of your oil feed/return lines. It looks nicer, resists corrosion, and are far more flexible.
• One of the most overlooked parts of turbo setups:
TUNE. Your tune will make or break your setup. Buy a Hondata S200. If you have the cash, get the S300. That thing is SO amazing. Have your car tuned professionally immediately after installing everything. If not, you WILL eventually detonate (detonation = bye bye motor).
• Another important aspect that is always very heavily overlooked: Suspension and tires. You said you already have Skunk2 coils, that's cool. Make sure your camber toe is in check. If not, get a camber kit (a lot of people will say it's unnecessary. They're cheap, and very effective. It worked great for me). Stay on top of your tires/alignment.
Backtracking a bit, but when you build your block, pick up a kit of ARP headstuds, and a cometic head gasket. That will keep the seal between your block and head nice and tight during high boost. Also, if you're using the b16 head, consider a valve/guide job while you're having the block machined.
Sorry if this post was overly long! I know these are all issues I ran into when I first stepped into boost. If i had known all of this stuff, it would have saved me a LOT of headache/scrilla. Don't end up like me, and dump $1200 into changing your turbo kit 3 times due to cheap crap. Do it right the first time! Good luck, and welcome to boost fever!
