[Sir_muffins]

I'm building a mild 460 for my mach 1 just top end parts not looking to make a ton of power until I forge the bottom (planned for my spare motor) what kind of boost would I be making I'm only looking at making somewhere in the low 400 range at the crank with the top end setup I have. I've been told these lowers can handle 500-600 stock.

(I'm pretty new to building engines I'm using knowledgeable friends, forums, and YouTube for most of my info)

 

[MrScharfenberger]

I'm not really sure what your asking but I can tell you that these motors can make 400+ HP very easily and you don't need any boost to do it.

 

[PSIG]

A bone-stock [email protected] (dog) version of the engine would make over 400hp on 7psig boost at 5000 rpm , flowing 45.6 lb/min through the turbos and 609 CFM through the carb or throttle body. That's assuming a lot, such as 0.55 BSFC (lb/HP/hr fuel flow), 75% compressor efficiency, and so on.

10 psig would net around 450, and 1 BAR (14.7 psi) would get you 520+ at 800 CFM. Adding 700cc/min (±20%) water injection would bring ±600hp, still at 5000 rpm. Any minor airflow and exhaust improvements would jump those numbers substantially. A stock block will easily take more than that on good fuel and a good tune as boost is lower stress than rpm. Don't get greedy or sloppy. Do have fun.

 

[Sir_muffins]

I'm not really sure what your asking but I can tell you that these motors can make 400+ HP very easily and you don't need any boost to do it.

im really trying to see what kind of power increase i could get from a twin turbo setup using the cheap powerstroke diesel turbos as i'm not trying to overdo my lower. i already have parts for the top end heads cam etc and they should be putting me around the 400-450hp range

A bone-stock [email protected] (dog) version of the engine would make over 400hp on 7psig boost at 5000 rpm , flowing 45.6 lb/min through the turbos and 609 CFM through the carb or throttle body. That's assuming a lot, such as 0.55 BSFC (lb/HP/hr fuel flow), 75% compressor efficiency, and so on.

10 psig would net around 450, and 1 BAR (14.7 psi) would get you 520+ at 800 CFM. Adding 700cc/min (±20%) water injection would bring ±600hp, still at 5000 rpm. Any minor airflow and exhaust improvements would jump those numbers substantially. A stock block will easily take more than that on good fuel and a good tune as boost is lower stress than rpm. Don't get greedy or sloppy. Do have fun.

Gotcha so with the setup I have I need to forge the lower before I add any boost as I'd be well over what the stock lower could handle. Thank you for all the info provided (although I only really understood a bit of the application side of it seems it's time to research more).

 

[Werecow]

When using boost what you have to watch for is the increase of torque at lower to midrange rpms. When the boost comes on at the midrange you get a huge increase in torque that parts weren't designed for at that speed. That's why the need for forged parts when pumping up the boost. Do a lil research on some of Richard Holdner's YouTube's on boost and you'll see what I mean about the midrange torque bump..

 

[ArnoldRC]

Best advice I think would be to single turbo what you have, and learn as much as you can from that project, then start planning your twin setup. Tuition isn't free, but as you move through a single turbo on your stock setup, you'll find that the more you learn, the more you'll apply to your twin setup. The more you apply, the less money you'll spend changing your mind and buying parts. It'll be less expensive in the long haul.

Pick a goal for your single setup, and use your network to build that up first. PSIG is a good resource, as well as many others on this board, but they won't be able to help unless you've got a clear direction, and a clear endgame.

 

[PSIG]

Gotcha so with the setup I have I need to forge the lower before I add any boost as I'd be well over what the stock lower could handle.

I think you mis-read. I said stock. Bone stock. Only minor changes such as re-gapping the rings and fresh valve springs. Stock crank, rods, pistons, heads, cam, intake—everything. 400 isn't even breathing hard. 700 is easy, but you have to pay attention. You don't get to say "Oops, that was stupid." more than once, no different than a 700hp NA engine.

I would have no issues running stock cast pistons to over 700 on a stock BBF, with those minor mods, and holding rpm to 5000. Reliably. Yes, it's been done and to much higher levels before. Personally, I would go hyper or maybe forged to play 800 or higher, and only to avoid piston land crushing (more boost) or skirt cracking (more rpm). This is the point about letting the boost do the work, as you can have primary assembly stress from boost or rpm. Pick one. Stick to it.

Right now, some are hollering at their screens with something about having to run forged this and that. I agree, if you run crappy fuel, or poor tuning, or other things that add huge stress to the combo. For that, it needs to be armor-plated, and even then is risky. You have to ask yourself; what causes crank failure? Rod failure? Piston failure? Block failure? And they all circle back to some basic elements of rpm, fuel and tuning, the sources of the majority of failures. Keep rpm limited, and invest in good fuel and good tuning. Have fun.

 

[MrScharfenberger]

I think you mis-read. I said stock. Bone stock. Only minor changes such as re-gapping the rings and fresh valve springs. Stock crank, rods, pistons, heads, cam, intake—everything. 400 isn't even breathing hard. 700 is easy, but you have to pay attention.

I don't think you'd even have to regap the rings for only 400HP.

 

[boss 9 howard]

I'm building a mild 460 for my mach 1 just top end parts not looking to make a ton of power until I forge the bottom (planned for my spare motor) what kind of boost would I be making I'm only looking at making somewhere in the low 400 range at the crank with the top end setup I have. I've been told these lowers can handle 500-600 stock.

(I'm pretty new to building engines I'm using knowledgeable friends, forums, and YouTube for most of my info)

If you ask enough questions,you will find that a 460 can make god like torque at a VERY low rpm.Diesel like power is common and expected from an average build.Turbos are not going to help that.Positive displacement blowers do that.Since the patents are no longer an issue,Kenny B, and whipple have developed there own sizes.I have no available kit as of this moment.Stock may pickup by turkey day.460 heads have marginal exhaust flow to start with.Jamming twin turbos on it would more than likely result in a fire ball consuming you mach.Running too lean,fire ball.Back pressure from entire exhaust system same O.Too much advance,same O,not enough radiator,ditto.Turbos are more of a violent on/off switch than a linear provider on big motors.Mounting and plumbing turbos are no joy in mudville either.I near wrecked a machine when the tranny contents decided to lube the tires.There are more than a few more things you need to know to avert tragedy.There are other street oriented big power guys here.Not hard to weed them out.Best advice,Learn before you spend. good luck b9h

 

[boss 9 howard]

I don't think you'd even have to regap the rings for only 400HP.

Dear mister Shark:I have never read a poor or misleading answer from you.Thankyou for helping make this site a success.b9h

 

[Werecow]

If you ask enough questions,you will find that a 460 can make god like torque at a VERY low rpm.Diesel like power is common and expected from an average build.Turbos are not going to help that.Positive displacement blowers do that.Since the patents are no longer an issue,Kenny B, and whipple have developed there own sizes.I have no available kit as of this moment.Stock may pickup by turkey day.460 heads have marginal exhaust flow to start with.Jamming twin turbos on it would more than likely result in a fire ball consuming you mach.Running too lean,fire ball.Back pressure from entire exhaust system same O.Too much advance,same O,not enough radiator,ditto.Turbos are more of a violent on/off switch than a linear provider on big motors.Mounting and plumbing turbos are no joy in mudville either.I near wrecked a machine when the tranny contents decided to lube the tires.There are more than a few more things you need to know to avert tragedy.There are other street oriented big power guys here.Not hard to weed them out.Best advice,Learn before you spend. good luck b9h

Wise words... Do your research before spending any $$$$! And KISS.... Keep It Simple Stupid! Best rule to live by!

 

[PSIG]

Let's not start A pissing-match on turbo vs super charger, please. Use what you like, and point-out potential benefits of specific types or combinations; but let's not spread generalities of worst-case, as we have enough of that in the web now. Any system can be configured to provide solid solutions, and turbo or supercharger is mostly a preference rather than a requirement. Do your homework, make a plan, and do your thing.

I don't think you'd even have to regap the rings for only 400HP.

Agreed, but (especially turbo) it usually doesn't stop at the original target power. The urge and capability to just turn that knob a little more gets to most folks. As Hastings and others showed the appropriate wider ring gaps to have low impact on sealing and leak-down, I'd prep the engine for up-to the max it could see with that combo, before dropping it in. The other up-side is that the option to increase the power without increasing rpm is easily available, or decrease it if proper-grade fuel isn't available. Human nature insurance.

I have no available kit as of this moment.

OK, so the perspective of a supercharger salesman is apparent. Let me be clear—I love all forms of power adders, including superchargers. I'm here to help however I can, not sell stuff. Some of those statements are way-out there, and either don't apply or are also applicable to SCs. Let's be fair and considerate, and address the OP's questions. My goal is to see user satisfaction, including owner goals, costs, skills, etc. The OP said turbo, so I'll find the combination that does what he wants, likely less costly, more reliable, and easier than other ways. It's his goals that count, not anyone else's.

 

[boss 9 howard]

Let's not start A pissing-match on turbo vs super charger, please. Use what you like, and point-out potential benefits of specific types or combinations; but let's not spread generalities of worst-case, as we have enough of that in the web now. Any system can be configured to provide solid solutions, and turbo or supercharger is mostly a preference rather than a requirement. Do your homework, make a plan, and do your thing.

Agreed, but (especially turbo) it usually doesn't stop at the original target power. The urge and capability to just turn that knob a little more gets to most folks. As Hastings and others showed the appropriate wider ring gaps to have low impact on sealing and leak-down, I'd prep the engine for up-to the max it could see with that combo, before dropping it in. The other up-side is that the option to increase the power without increasing rpm is easily available, or decrease it if proper-grade fuel isn't available. Human nature insurance.
OK, so the perspective of a supercharger salesman is apparent. Let me be clear—I love all forms of power adders, including superchargers. I'm here to help however I can, not sell stuff. Some of those statements are way-out there, and either don't apply or are also applicable to SCs. Let's be fair and considerate, and address the OP's questions. My goal is to see user satisfaction, including owner goals, costs, skills, etc. The OP said turbo, so I'll find the combination that does what he wants, likely less costly, more reliable, and easier than other ways. It's his goals that count, not anyone else's.

The ls chevy is the most turbo ready V8 ever produced.Optimized ports,light crank,can handle extended periods of 6K plus.All the things an eighty six pound crank behemouth does not enjoy.I do not sell (kits) without installation.There are way too many processes that can be over looked by newcomers.The first thing I install is a big *** fire extinguisher.Second is a big red fuel pump slam button on the dash.Then I get down to the rat killing.Safety first,parts match engineering second. I love my big block,took to my bed for a week when I sold my cross bolt ford stuff.But the engineering in the 460 brutal.I will never part with mine. b9h

 

[MrScharfenberger]

Dear mister Shark:I have never read a poor or misleading answer from you.Thankyou for helping make this site a success.b9h

Thanks man.. I don't know beans but I try anyway.

 

[Werecow]

Could also just go with some squeeze? An good 250-300 hp NOS setup will work good if you've got the rings gapped just like in a turbo and you pull enough timing out? Just a thought to toss an apple in this oranges discussion....