Author Topic: 5.7 or 6.1 forced induction (Read 19775 times)

GreenFish · « **on:** July 03, 2012 - 09:31:33 AM »

So I'm still back and forth on what engine I am going to eventually build for the cuda. I can go with another B/RB and save lots of cash because it already has a 440 with edlebrock heads and some other goodieds that I could just swap over to the new motor.

But on the other hand I love the idea of a new Gen3 Hemi, Its lighter, modern, I'll run EFI ect. But if I do a gen3 hemi I would like to go all out and throw a supercharger on it or something like that.

So my question or discussion topic would be, what would the boost or HP limitations be for the stock bottom ends of the 5.7 or 6.1? I know I can build a bottom end as strong as I can afford but I am talking stock bottom end from a pull out motor. Would 8-10 psi work? Could I see 600hp?

thedodgeboys · « **Reply #1 on:** July 03, 2012 - 10:01:23 AM »

Depends on if it's a 5.7 6.1 or 6.4 as your starting point, but I think they advertise between 100-150 HP gains on stock motors.

MizzouRT · « **Reply #2 on:** July 03, 2012 - 10:59:55 AM »

The weak spot will be the stock cast pistons - they are not designed for supercharging and frequently break with supercharging. 10 psi of boost is too much for the stock pistons. Probably more like 6-8 pounds max, which should get you the 100-150 hp gain that DodgeBoys described.

Let me back up and ask what your intended purpose is. I'm thinking you want a 500+ hp street engine that is reliable and gets good enough fuel economy to allow some extended crusing ranges? If you want 550 hp, then the 440 will be cheaper even if you are starting from scratch (never mind already having the 440 with aluminum heads!) but cruising range can be an issue with that much displacement, cam & carb. A modern hemi with forced induction can give you both the power and cruising range, especially if you go with VVT and EFI.

The VVT engines will make more power and deliver better fuel economy, but they are harder to tune and you are pretty much stuck with the stock cams. Almost no cams out there and tuning is a real problem with VVT. I see lots of complaints about VVT cam swaps that didn't add much power and constantly throw CEL warnings. If you want a supercharger, stick with the 5.7 or the 6.1. The 6.4 is a bored and stroked 5.7, and the thinner cylinder walls are going to limit boost to very modest levels even if you forge the internals. Dodge's upcoming factory supercharged engine will be 6.2 instead of 6.4 to avoid this. So with a clean sheet go for a 5.7 or 6.1, not 6.4 if you want to supercharge.

EFI is going to be more reliable and give better fuel economy, but tuning will require professional help. Bad tunes are another easy way to crater your modern hemi. Note if you get the 2011 or later harness the computer is locked and you won't be able to mod or tune at all, certainly no supercharger, so make sure the controller you get can be tuned.

If 500 hp / 500 TQ is enough power, you also might consider a crate 392 and skip the forced induction? It is 470 / 470 stock and adding headers without cats should put you right around the 500 / 500 mark. Will be simpler and more reliable than forced induction, and probably less coin up front.

Bottom line: plenty to like about a modern hemi swap, but far from a slam dunk. If you are just driving locally, the 440 will be cheaper and you can work on it yourself. It will also have more stage presence as the modern hemi is very smooth and far less noticeable than a RB. If you want road trip and cruising range capabilities, then the modern hemi is a clear winner.

MoparCar · « **Reply #3 on:** July 03, 2012 - 09:56:25 PM »

Check out Kenne Bell superchargers. Several options and they have a good reputation. They'll put down a lot of power.

Wes

GreenFish · « **Reply #4 on:** July 05, 2012 - 08:27:20 AM »

MizzouRT,

The bottom end is what i was most concerned with. And I think you answered my question, but does the stock 6.1 come with forged bottom end?

As far as tuning goes, I have no intention of using a stock ECU. Ill either use fast or Megasquirt.

Chryco Psycho · « **Reply #5 on:** July 05, 2012 - 05:29:35 PM »

I know the 5.7 comes with powered metal rods , not overly strong & not resizable , I think the crank is good but I would swap rods & pistons & go stroker & get a new crank !! Not sure how much a stock bottom end will take but it would worry me !!

ragtopdodge · « **Reply #6 on:** July 05, 2012 - 07:30:49 PM »

From allpar:

The SRT engine includes numerous modifications from the standard Hemi, such as:

Reinforced bulkheads.
Larger cylinder bores, by 3.5 millimeters, honed with torque plates to ensure a truer bore.
Oil squirters, aimed at the underside of each piston, aided by a special oil pump pressure relief valve.
Modified oil pan and windage tray.
Larger-diameter, flat-top pistons with high-load capability.
Revised connecting rods using higher-strength powder metal material. New floating piston pins.
Crankshaft forged from micro-alloy steel, in tri-metal main bearings, with retuned damper.
Head ports designed with larger cross-sectional area. This allows 11 percent higher flow in the intake ports, and 13 percent higher flow in the exhaust ports.
A billet steel, high-strength camshaft features more overlap and lift for better performance.
Intake valves feature hollow stems and 2 mm larger heads. The hollow exhaust valve stems are filled with sodium to dissipate heat. Premium valve springs with external dampers enable higher engine speed operation to 6,400 rpm and allow the peak output engine speed to increase to 6,000 rpm from 5,000 rpm.
Specially designed intake and exhaust manifolds.
Cast aluminum intake manifold with shorter, larger-diameter and tapered runners for high-speed tuning. Internal runners are core-dipped to smooth the runner finish and improve air flow.
14% higher fuel injector flow capacity; higher-flow air cleaner box with a tuned resonator delivering a deep performance sound character (and good for an extra eight horsepower).
Exhaust headers are individual tubes encased in a stainless steel shell. Exhaust runners allow increased gas flow while maintaining fast catalyst light-off, while adding 12 horsepower over the 5.7-liter engine�s cast manifolds.
Dual knock sensors with premium fuel.

If you got the $$, ya, get a 6.1 or 6.4L Hemi and put a Kenne Belle on there. Insane HP. But...for the same price as all that, you may be able to get a Gen II stroker 540 NA Hemi. May not have as much HP as the Gen III hemi+supercharger, but will have definite WOW factor opening the hood (more so than to me, the supercharger).

MizzouRT · « **Reply #7 on:** July 10, 2012 - 01:01:07 AM »

As Chryco pointed out, the only thing forged is the crank. You don't have to worry about the rods with the stock pistons, as the pistons typically break first. But if you add forged pistons then the rods will be the next weak spot, so upgrade to forged rods if you go with forged pistons.

Fuel economy will be poor and weight will be higher, but bang-for-the-buck would probably be better with a Gen II crate hemi. I see Indy has a 790 hp / 700 torque 572 Hemi for $17,350 (the single 1050 4-bbl option). You are going to have to run a lot more than 6-8 lbs of boost with a Gen III hemi to make that type of power. Of course, the Gen II would be totally useless for long distance cruising, so again it comes back to what you want to do with the car. If you are wanting to do events like Power Tour or Drag Week, the Gen III with forced induction is going to be so much easier to live with. But the Gen III is never going to have the curb appeal or low speed cruising sound that the Gen II provides...

Link to prices on Indy Gen II crate engines:

http://www.indyheads.com/images/price2012.5.pdf

Modern Muscle · « **Reply #8 on:** July 11, 2012 - 09:43:47 PM »

The information posted so far is a little outdated so let me clear it up for you.

We have never seen a 6.1 fail because of the rods.
The weak point is still the pistons on the 6.1 or the 5.7L
A 5.7L can handle about 6lbs of boost.
The 6.1L can handle 8lbs safely. However we have developed a forged 6.1 drop in piston (Balancing required) that increases the durability. 14lbs of boost max
If doing a resto mod the ideal engine is either the 05-08 5.7L or the 05-08 6.1L tuning is the best on these motors.
The issue of the VVT cams before was that they we regrinds off the stock cam. However now there are new blank cores available and with the addition of a cam limiter we our now seeing bigger gains 80+RWHP

We have new 5.7L crate motors for under 5k and 6.1L crate motors for $6200.00 they are complete long blocks if any member here is interested give us a call we offer discounts to the members here.

Modern Muscle · « **Reply #9 on:** July 11, 2012 - 09:46:25 PM »

Also I own a 07 Magnum SRT/8 6.1L with a Vortec S/C she is running 520RWHP and 519TRQ at 7lbs of boost so the potential is there for big power

MizzouRT · « **Reply #10 on:** July 13, 2012 - 03:53:57 PM »

Yes, it is easy to make 500-650 hp with modest boost.

Here is how I look at cost:

crate 6.1 $6,000
complete EFI kit for 500+ hp engine with harness $4,800 (price from XV Motorsports)
supercharger kit for low boost applicatons $6,900 (price from Summit, you can spend more)

total for parts: $17,700

You can make 500-600 hp with a 440 for less coin. You can make 790 hp with a Gen III hemi for about the same coin. But done right, the supercharged Gen III will be far smoother, get better gas mileage, and require less maintenance. So it always comes back to what is important to you. The way I see it, the more you intend to drive the car and the farther you intend to drive, the more attractive the Gen III becomes.

leanburn · « **Reply #11 on:** July 14, 2012 - 11:06:04 AM »

i'm toying with the idea of a newer hemi conversion. around here the 5.7's are dirt cheap but the 6.1's are worth a fortune. i was thinking about a junkyard 5.7 and stroking to a 6.4. it would cost a little more than buying the 6.1 but it should be a better build with boost in mind. am i way off here or does this make sense?

GreenFish · « **Reply #12 on:** July 16, 2012 - 07:52:20 AM »

Quote from: MizzouRT on July 13, 2012 - 03:53:57 PM

Yes, it is easy to make 500-650 hp with modest boost.

Here is how I look at cost:

crate 6.1 $6,000
complete EFI kit for 500+ hp engine with harness $4,800 (price from XV Motorsports)
supercharger kit for low boost applicatons $6,900 (price from Summit, you can spend more)

total for parts: $17,700

You can make 500-600 hp with a 440 for less coin. You can make 790 hp with a Gen III hemi for about the same coin. But done right, the supercharged Gen III will be far smoother, get better gas mileage, and require less maintenance. So it always comes back to what is important to you. The way I see it, the more you intend to drive the car and the farther you intend to drive, the more attractive the Gen III becomes.

I think this is my goal, driveability. But I don't want to sacrafice power to do it either. The 6.1/5.7 just seems to be the way to go.

Modern Muscle · « **Reply #13 on:** July 16, 2012 - 06:35:26 PM »

Quote from: leanburn on July 14, 2012 - 11:06:04 AM

i'm toying with the idea of a newer hemi conversion. around here the 5.7's are dirt cheap but the 6.1's are worth a fortune. i was thinking about a junkyard 5.7 and stroking to a 6.4. it would cost a little more than buying the 6.1 but it should be a better build with boost in mind. am i way off here or does this make sense?

Those prices are way off there are plenty of other options out there then the XV

Modern Muscle · « **Reply #14 on:** July 16, 2012 - 06:38:59 PM »

Guys we have done alot of these conversions please give us a call our help is free!!!!

Author Topic: 5.7 or 6.1 forced induction (Read 19775 times)

GreenFish

5.7 or 6.1 forced induction

thedodgeboys

Re: 5.7 or 6.1 forced induction

MizzouRT

Re: 5.7 or 6.1 forced induction

MoparCar

Re: 5.7 or 6.1 forced induction

GreenFish

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Chryco Psycho

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ragtopdodge

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MizzouRT

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Modern Muscle

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Modern Muscle

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MizzouRT

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leanburn

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GreenFish

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Modern Muscle

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Modern Muscle

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