cast steel vs forged
Melting Slicks
Joined: Apr 2002
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From: down that one road next to that big tree
Re: cast steel vs forged (85vettelovin)
strength and ease of assembly. forged cranks generally have tighter quality control. the polishing is better & the quality is higher. scats 9000 cast steel crank is actually really good for a $200 crank. i was able to get 2-3 thousands for main clearances on all 5. it took a little work but the finish product was great. unless your going over 7000rpms for extended periods or making over 600hp the cast steel will work fine.
Team Owner
Joined: Sep 2001
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From: Athens AL
C7 of the Year - Unmodified Finalist 2021
C4 of Year Finalist (performance mods) 2019
Re: cast steel vs forged (85vettelovin)
Forged can handle more power, its very strong in comparison to cast or hyper pistons. Also pretty light.
Only problem is that its twice the price in some cases.
It really depends on what youre going with on the motor whether you really NEED to have forged internals.
Only problem is that its twice the price in some cases.
It really depends on what youre going with on the motor whether you really NEED to have forged internals.
Le Mans Master
Joined: Apr 2000
Posts: 6,341
Likes: 1
From: Shelton CT
Re: cast steel vs forged (vader86)
RUle of thumb I believe is :
NA power 4-500HP, cast 'should' last no problem.
Power Adder 4-500HP, cast will not last long.. (NOS/Super/Turbo)
Forged parts are, just as the name implies, harder treated metals.
NA power 4-500HP, cast 'should' last no problem.
Power Adder 4-500HP, cast will not last long.. (NOS/Super/Turbo)
Forged parts are, just as the name implies, harder treated metals.
Thread Starter
Instructor
Joined: Oct 2002
Posts: 115
Likes: 0
From: Greeley Co
Re: cast steel vs forged (85vettelovin)
how much stress is actually put on the crank while running nitrous? I know that running nitrous forged pistions are a great idea but what effect does nitrous have on the crank?
The reason I ask is because pretty soon here I am going to be building a street motor. I will be running 100 shot of nitrous on it but not alot. Only when i find my way down to the track. The motor should make between 430-450 hp. (not at the wheels) So forged pistions are a must but I am not sure between a scat 9000 series cast steel crank or going forged... I guess I just can't decide if the cost difference will be worth it, especially since nitrous will not be used very often..
[Modified by 85vettelovin, 9:54 PM 2/19/2003]
[Modified by 85vettelovin, 10:00 PM 2/19/2003]
The reason I ask is because pretty soon here I am going to be building a street motor. I will be running 100 shot of nitrous on it but not alot. Only when i find my way down to the track. The motor should make between 430-450 hp. (not at the wheels) So forged pistions are a must but I am not sure between a scat 9000 series cast steel crank or going forged... I guess I just can't decide if the cost difference will be worth it, especially since nitrous will not be used very often..
[Modified by 85vettelovin, 9:54 PM 2/19/2003]
[Modified by 85vettelovin, 10:00 PM 2/19/2003]
Race Director
Joined: Oct 2001
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From: Fear causes hesitaiton...and hesitation will cause your worst fears to come true. Houston TX
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Re: cast steel vs forged (85vettelovin)
In my opinion, if you can pull it off, spend the money up front and do it right, once. It will save time and $$$ in the long run. Just my .02
Team Owner
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St. Jude Donor '03-'04
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Re: cast steel vs forged (Rob 91Z07)
Castings are what they sound like. You take molten metal and pour it into a form and let it cool. Castings are more or less porous depending on the quality, and can have voids and cracks from the start.
Forging means taking a hot, plastic, malleable piece of stock, and placing it into a form, and then subjecting it to extreme pressure until it assumes the shape of the form. Little or no porosity, unidirectional grain, plastic stress and strain added to the structure, harder surface, etc.
Forging means taking a hot, plastic, malleable piece of stock, and placing it into a form, and then subjecting it to extreme pressure until it assumes the shape of the form. Little or no porosity, unidirectional grain, plastic stress and strain added to the structure, harder surface, etc.
Melting Slicks
Joined: Sep 2000
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From: PITTSBURGH PA
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Re: cast steel vs forged (Rob 91Z07)
that cast crank will last behind that nos i had many motors on nos and they all had cast cranks except 1 and never had a problem they should be good to 700 hp. rpm is what kills those cranks not the nos but i would put in forged pistons tho cast and hyper will work but i wouldnt chance it and some quality rod bolts also couldnt hurt either :cheers:
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Melting Slicks
Joined: Apr 2002
Posts: 3,019
Likes: 0
From: down that one road next to that big tree
Re: cast steel vs forged (CORKVETTE1)
that cast crank will last behind that nos i had many motors on nos and they all had cast cranks except 1 and never had a problem they should be good to 700 hp. rpm is what kills those cranks not the nos but i would put in forged pistons tho cast and hyper will work but i wouldnt chance it and some quality rod bolts also couldnt hurt either :cheers:
Drifting
Joined: Dec 2002
Posts: 1,861
Likes: 4
From: Houston TX
Re: cast steel vs forged (gtsyellow)
Part of the issue is how light you want to make your bottom end...if you want to save money and go cast, you're going to have a HEAVY bottom end. The only way you're going to get a lightweight crank or lightweight rods is to go forged. You'll have a hell of a time finding a cast crank that gets down under 53 or so lbs, whereas you can find 3.48" stroke forged cranks that will hold 900 HP and weigh 38 lbs (keep in mind we're talking about rotating mass here, not front end weight)...of course you could get a set of Fikse wheels for less than the cost of one of those cranks, but that's just an extreme to give you an idea of the differences.
Also, it's not just RPMs that hurt cranks, it's harmonics, which are a function of frequency (RPM) and amplitude (HP). The crank doesn't know that there's nitrous on the motor, it just knows the load that's transmitted to it through the rods.
Long and short, my opinion on the deal is that if you're going to build a motor that you plan on beating on, I'd put forged in it and be done (tighter quality control, stronger material, lighter cranks, stiffer cranks, easier to obtain necessary bearing clearances, etc, etc). If you're going to build a motor that's not going to be pounded, cast is fine as clearances aren't as critical, loads won't be as high, etc, etc.
Also, it's not just RPMs that hurt cranks, it's harmonics, which are a function of frequency (RPM) and amplitude (HP). The crank doesn't know that there's nitrous on the motor, it just knows the load that's transmitted to it through the rods.
Long and short, my opinion on the deal is that if you're going to build a motor that you plan on beating on, I'd put forged in it and be done (tighter quality control, stronger material, lighter cranks, stiffer cranks, easier to obtain necessary bearing clearances, etc, etc). If you're going to build a motor that's not going to be pounded, cast is fine as clearances aren't as critical, loads won't be as high, etc, etc.
Melting Slicks
Joined: May 1999
Posts: 2,037
Likes: 0
From: Sarasota FL
Re: cast steel vs forged (85vettelovin)
Keep in mind the tuning and assembly quality - a well built, well tuned cast motor will put up with more than a poorly tuned, poorly built forged motor.
Le Mans Master
Joined: Apr 2000
Posts: 6,341
Likes: 1
From: Shelton CT
Re: cast steel vs forged (Aaron's 87)
It's a reliability question.
Cast = not so relaiable on a street racer as cast. Nothing to it.
Build what you can afford. If you can afford, get forged internals, as it won't hurt anything, but will outlast any cast parts down the line, that's for sure.
:auto:
Cast = not so relaiable on a street racer as cast. Nothing to it.
Build what you can afford. If you can afford, get forged internals, as it won't hurt anything, but will outlast any cast parts down the line, that's for sure.
:auto:
Drifting
Joined: Dec 2002
Posts: 1,861
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From: Houston TX
Re: cast steel vs forged (Darkness)
There's no point in going forged unless your gonna make an engine that only see's race.
Race Director
Joined: Oct 2002
Posts: 13,717
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From: RI
Re: cast steel vs forged (MrNuke)
RUle of thumb I believe is :
NA power 4-500HP, cast 'should' last no problem.
Power Adder 4-500HP, cast will not last long.. (NOS/Super/Turbo)
Forged parts are, just as the name implies, harder treated metals.
NA power 4-500HP, cast 'should' last no problem.
Power Adder 4-500HP, cast will not last long.. (NOS/Super/Turbo)
Forged parts are, just as the name implies, harder treated metals.
What do you or anyone else think? I'm curious cuz i'm moving in this direction
Kitt
Drifting
Joined: Dec 2002
Posts: 1,861
Likes: 4
From: Houston TX
Re: cast steel vs forged (kittmaster)
RUle of thumb I believe is :
NA power 4-500HP, cast 'should' last no problem.
Power Adder 4-500HP, cast will not last long.. (NOS/Super/Turbo)
Forged parts are, just as the name implies, harder treated metals.
Here is a real specific question, you mention power adders like a SC. If i put a SC on mine it looks like I'll be sitting around 430 ish at the RW. Are you saying that the internals will not last long under these conditions with normal driving, semi monthly quarter mile runs, and occasional getting all over it?
What do you or anyone else think? I'm curious cuz i'm moving in this direction
NA power 4-500HP, cast 'should' last no problem.
Power Adder 4-500HP, cast will not last long.. (NOS/Super/Turbo)
Forged parts are, just as the name implies, harder treated metals.
Here is a real specific question, you mention power adders like a SC. If i put a SC on mine it looks like I'll be sitting around 430 ish at the RW. Are you saying that the internals will not last long under these conditions with normal driving, semi monthly quarter mile runs, and occasional getting all over it?
What do you or anyone else think? I'm curious cuz i'm moving in this direction
THE CRANK AND RODS DON'T KNOW IF THE ENGINE'S FORCED INDUCTION OR NOT!!! THEY KNOW POWER!!!
Now, if you're looking at pistons, that's another story due to the heat that is transferred to the pistons from non-intercooled systems, but as long as there's enough oil on the wrist pins, the rods STILL won't know if there's a power adder or not (I've seen wrist pins with insufficient oiling blue the ends of some high $$$$ rods within 10 minutes on an engine dyno).
To anwer your question Kit, I'd be a little leary of trying to go for that much power on a stock cast crank if the motor will be abused. It's not that the crank will break and send pieces and parts flying out of the bottom of the motor or anything, you will just wear out the internals faster and need a rebuild sooner. To give you an idea of what I mean, my car which made 228 rwhp on it's last dyno pulls (two years ago) only got 60k miles out of the motor before it needed a rebuild (rings were toast, the main bearings were solid copper, and the crank was wobbling so badly from the excessive bearing clearance that I couldn't get a front seal or a 1-piece rear main to live for more than ~6 months before they needed replacement). You're talking about doubling that power (at the wheels) with the same internals. The motor just simply won't last that long. I'm a big proponent of the theory that if you want to build a sporty, strong motor then do it all the way. If you want a stock motor, build a stock motor. I'm in the middle of rebuilding my motor right now, and because I'm a broke (graduate student), I'm going back stock. I'm saving up money, however, to build a motor over the summer with a Cola superlight crank, Oliver rods, JE pistons, etc, etc. I KNOW my current motor won't last very long the way it's treated (run harder than you intend, but also at a lower power level), so I'm already planning for the motor that I will build that I know will last much longer.
Melting Slicks
Joined: Jan 2002
Posts: 3,159
Likes: 0
Re: cast steel vs forged (CorvetteZ51Racer)
a cast crank will fair you well.
i'm looking around 500hp NA and 200+ shots of nitrous on a bolt main.
many engine builders havee told me scat 9000.
The scat 900 is more than enough, especially with nitrous-
you probobly wont be reving that high.
I know i'm going 65-6700rpms NA and 6200 with the bottle.
:party:
id get forged pistons and good rods, but you honestly have no need for a forged crank with a 100hp shot.
there is a rotating assembly GP for scat and callies i think on camaroz28.com
check it out :cool: :cheers:
good luck
just make sure its properly balanced and the clearances/tq specs are good more than anything
[Modified by TreyZ28, 3:59 PM 2/20/2003]
i'm looking around 500hp NA and 200+ shots of nitrous on a bolt main.
many engine builders havee told me scat 9000.
The scat 900 is more than enough, especially with nitrous-
you probobly wont be reving that high.
I know i'm going 65-6700rpms NA and 6200 with the bottle.
:party:
id get forged pistons and good rods, but you honestly have no need for a forged crank with a 100hp shot.
there is a rotating assembly GP for scat and callies i think on camaroz28.com
check it out :cool: :cheers:
good luck
just make sure its properly balanced and the clearances/tq specs are good more than anything
[Modified by TreyZ28, 3:59 PM 2/20/2003]
Le Mans Master
Joined: Jul 1999
Posts: 8,683
Likes: 6
From: Phoenix AZ
Re: cast steel vs forged (kittmaster)
Here is a real specific question, you mention power adders like a SC. If i put a SC on mine it looks like I'll be sitting around 430 ish at the RW. Are you saying that the internals will not last long under these conditions with normal driving, semi monthly quarter mile runs, and occasional getting all over it?
What do you or anyone else think? I'm curious cuz i'm moving in this direction
Kitt
What do you or anyone else think? I'm curious cuz i'm moving in this direction
Kitt
Race Director
Joined: Oct 2002
Posts: 13,717
Likes: 5
From: RI
Re: cast steel vs forged (Zix)
was thinkin 8 psi (seen it done everywhere) but if 6 is recommended. I have 3.45 gears and already at 340 plus now. Will know for sure this spring. Done cat back, headers, intake, TB, and other stuff. Want to get inside the engine soon for cam, lifter, and other goodies but that will be later it seems. Any comments/ideas?
Melting Slicks
Joined: Jan 2002
Posts: 3,159
Likes: 0
Re: cast steel vs forged (CorvetteZ51Racer)
RUle of thumb I believe is :
NA power 4-500HP, cast 'should' last no problem.
Power Adder 4-500HP, cast will not last long.. (NOS/Super/Turbo)
Forged parts are, just as the name implies, harder treated metals.
Here is a real specific question, you mention power adders like a SC. If i put a SC on mine it looks like I'll be sitting around 430 ish at the RW. Are you saying that the internals will not last long under these conditions with normal driving, semi monthly quarter mile runs, and occasional getting all over it?
What do you or anyone else think? I'm curious cuz i'm moving in this direction
I honestly don't know where this distinction between "power adder HP and non-power adder HP" comes from....it's all crap.
THE CRANK AND RODS DON'T KNOW IF THE ENGINE'S FORCED INDUCTION OR NOT!!! THEY KNOW POWER!!!
Now, if you're looking at pistons, that's another story due to the heat that is transferred to the pistons from non-intercooled systems, but as long as there's enough oil on the wrist pins, the rods STILL won't know if there's a power adder or not (I've seen wrist pins with insufficient oiling blue the ends of some high $$$$ rods within 10 minutes on an engine dyno).
To anwer your question Kit, I'd be a little leary of trying to go for that much power on a stock cast crank if the motor will be abused. It's not that the crank will break and send pieces and parts flying out of the bottom of the motor or anything, you will just wear out the internals faster and need a rebuild sooner. To give you an idea of what I mean, my car which made 228 rwhp on it's last dyno pulls (two years ago) only got 60k miles out of the motor before it needed a rebuild (rings were toast, the main bearings were solid copper, and the crank was wobbling so badly from the excessive bearing clearance that I couldn't get a front seal or a 1-piece rear main to live for more than ~6 months before they needed replacement). You're talking about doubling that power (at the wheels) with the same internals. The motor just simply won't last that long. I'm a big proponent of the theory that if you want to build a sporty, strong motor then do it all the way. If you want a stock motor, build a stock motor. I'm in the middle of rebuilding my motor right now, and because I'm a broke (graduate student), I'm going back stock. I'm saving up money, however, to build a motor over the summer with a Cola superlight crank, Oliver rods, JE pistons, etc, etc. I KNOW my current motor won't last very long the way it's treated (run harder than you intend, but also at a lower power level), so I'm already planning for the motor that I will build that I know will last much longer.
NA power 4-500HP, cast 'should' last no problem.
Power Adder 4-500HP, cast will not last long.. (NOS/Super/Turbo)
Forged parts are, just as the name implies, harder treated metals.
Here is a real specific question, you mention power adders like a SC. If i put a SC on mine it looks like I'll be sitting around 430 ish at the RW. Are you saying that the internals will not last long under these conditions with normal driving, semi monthly quarter mile runs, and occasional getting all over it?
What do you or anyone else think? I'm curious cuz i'm moving in this direction
I honestly don't know where this distinction between "power adder HP and non-power adder HP" comes from....it's all crap.
THE CRANK AND RODS DON'T KNOW IF THE ENGINE'S FORCED INDUCTION OR NOT!!! THEY KNOW POWER!!!
Now, if you're looking at pistons, that's another story due to the heat that is transferred to the pistons from non-intercooled systems, but as long as there's enough oil on the wrist pins, the rods STILL won't know if there's a power adder or not (I've seen wrist pins with insufficient oiling blue the ends of some high $$$$ rods within 10 minutes on an engine dyno).
To anwer your question Kit, I'd be a little leary of trying to go for that much power on a stock cast crank if the motor will be abused. It's not that the crank will break and send pieces and parts flying out of the bottom of the motor or anything, you will just wear out the internals faster and need a rebuild sooner. To give you an idea of what I mean, my car which made 228 rwhp on it's last dyno pulls (two years ago) only got 60k miles out of the motor before it needed a rebuild (rings were toast, the main bearings were solid copper, and the crank was wobbling so badly from the excessive bearing clearance that I couldn't get a front seal or a 1-piece rear main to live for more than ~6 months before they needed replacement). You're talking about doubling that power (at the wheels) with the same internals. The motor just simply won't last that long. I'm a big proponent of the theory that if you want to build a sporty, strong motor then do it all the way. If you want a stock motor, build a stock motor. I'm in the middle of rebuilding my motor right now, and because I'm a broke (graduate student), I'm going back stock. I'm saving up money, however, to build a motor over the summer with a Cola superlight crank, Oliver rods, JE pistons, etc, etc. I KNOW my current motor won't last very long the way it's treated (run harder than you intend, but also at a lower power level), so I'm already planning for the motor that I will build that I know will last much longer.
but what do i know.
I'm an NA guy
i'm a parrot when it comes to FI :cheers:
bah, just take out a big loan and get a full billet bottom end :lolg:
i have billet rods-
its nice knowing my rods wont stretch (although my crank may explode, my rear is a ticking timebomb and the Trans... lets just pray)
[Modified by TreyZ28, 4:16 PM 2/20/2003]