How good is the new Hemi, REALLY?

[hemicop]

So I ordered a S/S Challenger (please, we can argue that later) and in planning on actually running the car, I got to talking to a friend of mine that works at a dealership. He's ASE certified, has worked on the new Hemi since it came out and has a good amount of racing experience. In talking to him about the motor & keeping in mind Hot Rod Magazine's article from last year or so, it was his opinion the motor isn't really all that good, stock. While the design itself is obviously potentially good, his feelings are that the rods & pistons are weak and that the block itself is so thin (even the 6.1) that the only way to seriously race this motor is to replace the pistons, rods & fill the block to insure durability. Now no one I know of around here seriously races one of these engines, & HRM conceded in their article the rods are the weak point of the engine but does/has anyone out there SERIOUSLY raced or tested this engine to see just how good a race motor it is? My backyard engineering experience tells me this motor has great potential but with a weak foundation (the block) do guys like me that plan/hope to race the new Hemi have to walk on eggshells while we're doing it? ...... Thoughts/ Opinions?

 

[abodyjoe]

well there is a guy at BBD and i think i saw him here he goes by the screen name MomsR/T. he has don alot or work with them.. says the 5.7 is a better motor to build.. he is running carbs. and has some in the 10's from what a recall.. he says they are awesome motors. he also says there is a ton of small things you can do to really make them run... see if you can find him here or at BBD and talk it over with him....

 

['70_Duster_340]

Congratulations on the new Challenger !!! I've got around 8,000 miles on my 6.1 Charger SRT8, and I've raced it (mostly for fun) several times the past two seasons ... You might wanna check out the Charger forum, if you haven't already ?? There's a ton of guys there who have done all kinds of mods to their motors... http://www.chargerforums.com/forums/index.php

I don't know how serious you're gonna get racing it, but the motor seems to be pretty reliable by most accounts.. If you're gonna supercharge or turbo it, then from what I've read you'll need to beef up the bottom end ... The weakest point in the SRT8's so far seems to be the half shafts.. The left one in particular seems problematic when you start beefing things up, or using drag radials.. I've seen a few videos of guys snapping them at the track ...

The 6.1 in my car came with a 203 degree thermostat, which I change to a 176 for the Summer .. I don't care what anyone says, but with the stock thermo it'll run up to 215 -225 degrees and "they" say it's OK..

Coolant gunk build-up has been an issue, and I've had my engine flushed and filled twice so far, and each time the dealer replaced the cap and over-flow bottle .. (John at Wilson Dodge in Torrington, CT is the best service manager I've ever dealt with, just an awesome guy).. The gunk is a nasty, white substance and when you remove the cap has a seriously strong ammonia smell, which CAN'T be good ?? I'm going to install a coolant filter to remedy this in the Spring...

Again, I'm far from the serious drag racer, but I've read a ton, and I just LOVE that hemi !!! If I were 20 years younger I'd be selling my Charger and ordering the Challenger, but I've gotten used to the four-door family car that'll run very low 13's, basically stock ...

Best of luck to ya !!

Kenny

 

[Marshalearp]

I wouldn't worry about component strength too much. I have a 6.1 in a 1969 Dart GTS and although I haven't run the car at the track, I have run it pretty hard elsewhere. These engines are a jewel of engineering. They've removed weight where it served no purpose, but left it or added where it would be of advantage. The machine work is beautiful and precise. The blocks are certainly not weak. Indy Cylinder Head is pounding these blocks hard in development programs every day, with no change other than billet main caps. As to the statement that "the rods are the weak link" ; every engine has a weak link. That does not mean that the rods are weak. Powdered metal technolgy is well established and accepted in O.E.M. performance applications. GM has used it in the LS series engines for years with high rates of reliability. On tne other hand, no cast piston should be run much higher than 6500 on a regular basis. If you are planning to RPM this engine, then yes, 4340 rods and forged pistons, for certain; but that is no different than a 340, 360 or any big block engine. The real story on these engines is the heads. There is nothing like these heads on any production small block of any make. 368 cfm @ .600! Power like you cannot believe. Torque curve as flat as Kansas. Hope this helps you sleep better. Good luck with your new ride.

 

[waynebo]

you need to pickup the latest issue of engine master,,winter 2007 issue.
they put a paxton on a 5.7" hemi and make 720 hp with only 10 psi boost on the stock bottom as delivered from the factory..
They do admit thats pushing for factory pistons though,,i think times going to prove it to be a great engine but your right on thin cylinder walls that they engineer into all new engine,,that will be the ultimate limit,,,,

 

[hemicop]

Thanks, guys! I know of ICH and their work and knew lots of guys raced the cars, but getting a broader view of this engine is what I'm trying to do. Figuring this car will fall somewhere around SS/FA or E, that means needing somewhere around 650 reliable hp, normally aspirated and I think it shoudn't be a problem. From what I've read and now heard I'm even more excited about the project. Now if they build it as a carbed engine instead of FI that would make it easierrayer:

 

[345man]

try the guys at arrington engines, they have the new hemis as crates but alot of horsepower, carbs or i think fuel injections they have a web sight, italked to them at bristol and were very knowledgable:toothy7:

 

[GoodysGotaCuda]

That have very high potential out of them, my dads is 525 n/a, purrs like a kitten till opened up. nasty street motor

 

[djwhog]

Some changes are in store in 2008 -2009 too.

from allpar's site:

The Hemi engine is set for an upgrade, which may be why the non-SRT Challenger will take some time to show up. By 2009, Chrysler will have variable cam timing set up for its Hemi engines, neatly leapfrogging most variable-valve timing systems. The multiple displacement system is expected to remain for most, if not all, 5.7 Hemis. A 6.4 liter version is still expected, with 450-500 hp, though whether this is earmarked for the Challenger or not is still in question.