NEW HEMI 5.7 , 345 hp , REAR WHEEL HP ????????

[daytonalo]

A new 5.7 hemi is 345 hp, and old school 440 is 375 rated at crank . My question is , what motor is more powerful ?? The Hemi  in HP , the  440 in Torque ?

[firefighter3931]

A new 5.7 hemi is 345 hp, and old school 440 is 375 rated at crank . My question is , what motor is more powerful ?? The Hemi  in HP , the  440 in Torque ?

The 440 makes about 30 more HP and 100 more ft lbs than the 5.7L hemi. Those ratings on the 5.7 are flywheel....not at the tire. 


Ron

[daytonalo]

Are you sure ?? 440 were gross HP 375 , new Hemi is net rating of 345

[Troy]

Are you sure ?? 440 were gross HP 375 , new Hemi is net rating of 345

True.

Your answer depends on your drive train. I've seen references of anywhere from 10-20% loss through the drive train. Since you're using a 4-speed you'll have less power lost in the transmission but I think you're using a Dana which has more drag than an 8 3/4". I've seen nearly stock trucks (automatics with the A/C and all that mess still attached) putting down 260 HP on the chassis dyno so that's more like 25% - but it's a truck.

It's really not hard to get more power out of the 5.7 - the reason a "cold air kit" is the #1 mod on the new vehicles with exhaust closely following. When putting the same engine into an older car you aren't limited by the factory design, EPA, or CARB standards (or to fuel injection for that matter). If you want to go crazy you can swap nearly all the 6.1 parts, go with after market heads, bump up the cam, and retune the computer (or use one of the after market ones). All that gets expensive though. Check out KRC, Sharadon, Street & Performance, Diablo Sport, and B&G (approximately 40 Hp and 40 ft/lbs better than stock just by tweaking the computer). In a car, this engine is easily capable of mid-high 20s mpg which might be important if you drive anywhere other than the track.

In case you're wondering, I have a 5.7 sitting in my garage now too.

Troy

[BrianShaughnessy]

There was a powerblock show last weekend where they went to BBK.    They dynod a new 5.7 Charger before they put on headers... they mentioned they usually saw about 280 before at the wheels.   I think they gained 20 sumething after headers.

A 440 vs 6.1 is a tossup.      Stock vs stock I'd give it to the 6.1.   Depending, etc. etc. etc. 

[Mike DC]

 
The new motors basically equal the HP of the old motors but they lose the torque.  More displacement = more torque = more gasoline burned.  You can't really cheat on this basic equation in any significant way. 




The 5.7L conversions sould like a nice option.  We'll probably see a lot of them in old Mopars in the coming years.  Modern motors usually come out of the trucks/cars with little or no wear on the hard parts.  And the 5.7L Hemis are plentiful enough to get cheap eventually. 

But those new 6-liter gen-III crate motors all over the Mopar press, 6.1L, 6.4L, etc . . .  they sound too expensive for what they are IMO.  For that money I think I'd rather just build an all-aluminum 500" wedge motor with that new World alloy block.   

 

[firefighter3931]

Are you sure ?? 440 were gross HP 375 , new Hemi is net rating of 345

The "net" rating is still at the flywheel...it just has all of the accessories bolted onto the front of the engine. 

The old ratings were w/o the PS pump, alternator etc....


Still, you can't beat torque for a street car.....torque rules ! 

A stock 440 made 480 ftlbs at 3200 rpm...the 5.7 L hemi can't match that...not even in the same ballpark. 



Ron

[Charger-Bodie]

Are you sure ?? 440 were gross HP 375 , new Hemi is net rating of 345

The "net" rating is still at the flywheel...it just has all of the accessories bolted onto the front of the engine. 

The old ratings were w/o the PS pump, alternator etc....


Still, you can't beat torque for a street car.....torque rules ! 

A stock 440 made 480 ftlbs at 3200 rpm...the 5.7 L hemi can't match that...not even in the same ballpark. 



Ron

I agree 100% Absolutly no comparison!! Torgue Rules

[daytonalo]

I always see these new 5.7 and 6.1 running super fast 1/4 times , I guess they are bullshitting us

[Mike DC]

 
1/4 mile times are more of a HP measurement than a torque measurement. 

You can wind a hot 4-banger up to 8000 rpm and get decent HP, but that doesn't mean it's on par with a 440 stroker that turns similar 1/4 mile times.  Big torque is a lot more fun on the street if you can afford the gas. 

 

[mally69]

 

[Troy]

I don't care so much about being able to afford the gas (the engine costs a lot more than the gas I use) but I hate stopping at every filling station. The Barracuda and Challenger only hold 12-13 gallons so at 6-8 (maybe 10-12) mpg I would barely get to mom's house and back without a fill up. The Chargers hold something like 19 gallons but I followed 69_500 home from Monster Mopar last year and he barely made it to Indy after filling up outside St Louis. I burned roughly 1/2 tank in the Barracuda (318 4bbl) over that stretch so that's 6-7 gallons vs 18-19.

Plus, I like technology so an electronically managed engine means more to me than others. I drive almost 90% on the highway at normal speeds. If I were racing every weekend I'd max out a big block for sure - but my cars will likely never see a track so that's not a concern. "Fun" to me also includes not breaking down or spending all my time tuning so something that "just works" when I turn the key is a priority. I think the engine choice should be based on personal/driving style so everyone is different. I also have five cars so I have more choices than most.

Troy

[Mike DC]

   
Some of these modern Hemis are being built with the electronically-controlled cylinder deactivation thingy now.  (V8 into 4-banger and seamlessly back again via computer.)  I've been wondering how long it's gonna take before someone rigs the system back up in an old muscle-era Mopar with a toggle switch or something. 

Going 6 liters into 3 liters is still a decent-sized motor for the car at a lazy highway cruising speed.  The factory system works reliably, and as long as you keep the EFI the uneven engine wear isn't gonna be very noticeable either. 

   

[Troy]

My Hemi is an 06 with MDS. The MDS also includes some goofy algorithm to keep you from accelerating too quickly (feels like a "hesitation" just before a shift) so I may bypass it like everyone else. It appears to be as simple as a cam/lifter swap (MDS uses a valve on each to pressurize/relax the lifter). I'll have to do more research but I know the 5.9 Magnum computers wouldn't work correctly if you disconnected the automatic transmission. Getting a computer from a stick shift truck solved that problem but I don't know if the same holds true for the Hemi. There's no way the truck 5-speed automatic will fit in the Challenger so that's out of the question! Perhaps a company like B&G can bypass the transmission code like they do for the security system when they reflash the computer for header/intake changes. If I do away with the MDS then the after market is full of computers that will work - but reflashing a stock one is cheaper and the computer came with the engine for free. I can always sell it if it won't work to offset the cost of a custom setup.

If all goes well, it may be on the road this summer. <crossing fingers and toes>

Troy

[694spdRT]

Sounds like an interesting project Troy. I have also played with the idea of a 5.7 Hemi in my Challenger. I would like to use a 833OD that is sitting in the shop behind it though. I talked with HotRod Lane(I think that's the name) about their harness and conversion setup in 2006 but the parts to put a 5.7 behind a stick shift were not really available. Hotrod directed me to Keisler at the time but they were no big help. I need to research that topic a little more.

[daytonalo]

I might go with the new intake and 4 bbl , throw my hemi box behind it and I have a cheap powerplant

[Mike DC]

The MDS thing is computer controlled as it comes from the factory, but it still basically uses engine oil pressure to deactivate the valve lifters.  Seems like that's mechanical enough to be re-rigged even if you ditched the factory electronics on the motor overall.    That's why I made the "toggle switch" comment. 

 

[Troy]

The MDS thing is computer controlled as it comes from the factory, but it still basically uses engine oil pressure to deactivate the valve lifters.  Seems like that's mechanical enough to be re-rigged even if you ditched the factory electronics on the motor overall.    That's why I made the "toggle switch" comment. 

 

Right, that valve I mentioned is for the oil pressure. I'm not so sure a simple toggle switch would do it though as I believe the computer also shuts off the fuel injectors and spark to those cylinders. I haven't studied it that much yet so I could very well be wrong. I think the fact that I'm putting it in a car that weighs 1,000-2,000 pounds less should probably make a huge improvement in mileage even without the MDS. I wish I could find a way to fit the 5-speed automatic OD in there without cutting away most of the floor but those things are MASSIVE! That's my big issue with keeping the factory computer as I know the older 5.9 would go into "limp home mode" or some other nonsense when the signal from the transmission wasn't there.

Troy

[daytonalo]

As I mentioned , I would go with 4 bbl and obviously a new intake. So the only electronics would be the crank trigger

[694spdRT]

The MDS thing is computer controlled as it comes from the factory, but it still basically uses engine oil pressure to deactivate the valve lifters.  Seems like that's mechanical enough to be re-rigged even if you ditched the factory electronics on the motor overall.    That's why I made the "toggle switch" comment. 

 

Right, that valve I mentioned is for the oil pressure. I'm not so sure a simple toggle switch would do it though as I believe the computer also shuts off the fuel injectors and spark to those cylinders. I haven't studied it that much yet so I could very well be wrong. I think the fact that I'm putting it in a car that weighs 1,000-2,000 pounds less should probably make a huge improvement in mileage even without the MDS. I wish I could find a way to fit the 5-speed automatic OD in there without cutting away most of the floor but those things are MASSIVE! That's my big issue with keeping the factory computer as I know the older 5.9 would go into "limp home mode" or some other nonsense when the signal from the transmission wasn't there.

Troy

Troy

I thought I read somewhere that the automatic transmission from a 300 or Charger was more compact than the truck version. Which do you have?

[Mopar2Ya]

Maybe I missed it, but don't forget power to weight(440 Vs. 6.1L)? The 0-60 on the GC SRT8 is ~4.5sec & 1/4 is ~13.3@105. The LX SRT8's have a higher 0-60 & mph.
http://thehemishop.com/COMPLETE_HEMI_ENGINES.cfm

[70_charger]

My Hemi is an 06 with MDS. The MDS also includes some goofy algorithm to keep you from accelerating too quickly (feels like a "hesitation" just before a shift) so I may bypass it like everyone else. It appears to be as simple as a cam/lifter swap (MDS uses a valve on each to pressurize/relax the lifter). I'll have to do more research but I know the 5.9 Magnum computers wouldn't work correctly if you disconnected the automatic transmission. Getting a computer from a stick shift truck solved that problem but I don't know if the same holds true for the Hemi. There's no way the truck 5-speed automatic will fit in the Challenger so that's out of the question! Perhaps a company like B&G can bypass the transmission code like they do for the security system when they reflash the computer for header/intake changes. If I do away with the MDS then the after market is full of computers that will work - but reflashing a stock one is cheaper and the computer came with the engine for free. I can always sell it if it won't work to offset the cost of a custom setup.

If all goes well, it may be on the road this summer. <crossing fingers and toes>

Troy

Just run heavier oil instead of the 5w20 it wont allow the MDS to work,so that means no 4 cylinder mode.
The Daytonas are rated 355hp and 390ftlbs of trq. at the crank.The  slush box trannys suck along with the drive by wire has massive throttle lag when you take off.

[Troy]

Heavier oil throws trouble codes in the computer. It will disable the MDS but does it by actually "gumming up" the works so I don't consider that a viable solution. The throttle lag is programmed into the firmware and not entirely due to the design of the throttle. It's a torque reduction algorithm in the computer (see above). Both can be worked around by reprogramming.

The Daytona engine is the same as an R/T correct?

Troy

[Mopar2Ya]

IIRC, MDS can be eliminated by changing the cam/lifter & plugs for the heads.
http://www.dynamicracing.com/customer/product.php?productid=563&cat=204&page=1

[Troy]

IIRC, MDS can be eliminated by changing the cam/lifter & plugs for the heads.
http://www.dynamicracing.com/customer/product.php?productid=563&cat=204&page=1

Yeah, I said that already...

Daytonalo didn't say what year he has or what it came out of but a 03-05 truck engine won't have the MDS any way. Mine is an 06. I am not positive when they put it on the cars but I thought the Magnum had it in 04. I suppose if he has the older one then all this information is useless.

In regards to what I said above about intake and exhaust being top on the list for modifications, I found this in an article on a cold air intake by Popular Hot Rodding:
The kit (PN 350-160) fits '05-06 Magnum and Charger RT models with the 5.7L Hemi engine and has an MSRP of about $250, although you can find it for about $200 if you shop around a bit. The Magnum was strapped to our dynojet and several base pulls were made. The best was a corrected 249 hp and 246 ft-lbs of torque.

Installation of the Airaid kit was a snap and took all of 15 minutes using only a flathead screwdriver. In fact, the installation book is only one page with eight simple steps. With the parts installed it was time to put the throttle down. After a couple pulls we recorded a best corrected-run of 282 hp and 304 ft-lbs of twist. That's a gain of 33 hp and a whopping 58 ft-lbs of torque.[ Quite a gain from a couple hundred bucks and 15 minutes of effort.
http://www.popularhotrodding.com/tech/0609phr_airaid_car_air_filter/index.html

Here's some numbers from an intake swap article by Mopar Muscle. This engine is running a FAST EFI system and they also mention bypassing the drive by wire throttle:
    * MP: Mopar Performance Single-Plane Four-Barrel Throttle Body  481 HP, 415 ft/lbs
    * 5.7 P/R: Production 5.7 Hemi Composite Plenum Ram  476 HP, 455 ft/lbs
    * SRT: Production 6.1 SRT-8 Plenum Ram  473 HP, 441 ft/lbs
http://www.moparmusclemagazine.com/techarticles/mopp_050057_dyno_torquing_hemi_intakes/index.html

More dyno numbers:
http://www.htmperformance.com/showthread.php?t=12

Comp Cams claims a 61 HP increase with a cam swap but no dyno numbers to back it up. I also saw some 40/40 increases claimed by some exhaust manufacturers.

By comparison, the 6.1 produces 425 HP (basically the same engine with a larger bore I believe) and there's a 6.4 Hemi due out in 2009 with 500 HP.

Troy