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  #1  
Old 09-27-2016, 09:48 AM
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5.7 Hemi Engine Mods

Hey all i'm new here! Just bought my wife an 08' WK Hemi. Looking to do some mods to the engine. I already did afe cold air, cnc machined throttle body and corsa mufflers (i bend my own exhaust). I'm looking at programmers next. any suggestions? Also what are some builds y'all have done without having to change engine internals (i'll wait to do that until i have more miles on her and she's ready for a rebuild) I'm not finding much on headers, intakes, fuel delivery...i haven't looked terribly hard yet but just wondering what y'all have done. Thanks!

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  #2  
Old 09-27-2016, 09:51 AM
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Quote:
Originally Posted by jakeo View Post
Hey all i'm new here! Just bought my wife an 08' WK Hemi. Looking to do some mods to the engine. I already did afe cold air, cnc machined throttle body and corsa mufflers (i bend my own exhaust). I'm looking at programmers next. any suggestions? Also what are some builds y'all have done without having to change engine internals (i'll wait to do that until i have more miles on her and she's ready for a rebuild) I'm not finding much on headers, intakes, fuel delivery...i haven't looked terribly hard yet but just wondering what y'all have done. Thanks!
A lot of 6.1 stuff will bolt on/ interchange to the 5.7. That would be a good start to look
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Old 09-27-2016, 11:22 AM
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Re: 5.7 Hemi Engine Mods

Depends on how much $$$$ you want to spend. I've done a bunch of relatively non-invasive mods. to mine (see signature) and have picked up nearly 100 hp. and increased the fuel economy by about 25%. I now routinely get 22-23 mpg on the highway with mine and it runs the high 13's/very low 14's in the quarter mile.

American Racing now makes headers for the 5.7 WK, but they're not cheap....~$1400-1500. I did cams in both my Hemi vehicles and this, along with my custom headers/cat. back, make up the bulk of the horsepower gains. The cam and kit cost around $600, with another ~$200 for a special 'heads on" valve spring changing tool and gaskets/miscellaneous. The things you've done so far, by themselves, don't help much. The biggest choke point that limits the Hemi's ability to process air/fuel is the crappy exhaust system, specifically the restrictive exhaust logs. As far as tuners go, both the Diablosport and Superchips (I have both) work well, but I favor the Superchips with the Advanced Transmission Tuning Application, mainly because it allows for FULL CONTROL of ALL up/down shift schedules as well as torque management. The Superchips with the ATT App., along with the Sonnax Line Pressure Booster and a Transgo Shift Kit (I installed it last year) make the transmission about as good as it can get.....which by the way is no where near as good as the NAG1.

To give you an idea of how bad the exhaust system is, here's a thread I did on the problem with the WK Hemi:

Exhaust manifold/header differences

Good luck on whatever you decide to do.
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Old 10-01-2016, 12:50 PM
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Re: 5.7 Hemi Engine Mods

Hey thanks man! I really appreciate the info. I have been on a ton of other threads reading up. Can't wait to dig into this. Did the custom headers you built bolt directly to the OEM exhaust? Also where did you get your cam kit from?
thanks again.
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Old 10-01-2016, 03:27 PM
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Re: 5.7 Hemi Engine Mods

Quote:
Originally Posted by jakeo View Post
Hey thanks man! I really appreciate the info. I have been on a ton of other threads reading up. Can't wait to dig into this. Did the custom headers you built bolt directly to the OEM exhaust? Also where did you get your cam kit from?
thanks again.
After they modified the mids for the headers it was basically a stock "Y" pipe, from headers to the muffler. The rest of the system is a completely custom straight through 3 in. dual muffler, single resonator setup.

My cam is a Frank's Racing Sidewinder. This particular grind has been around the Hemi LX community for about 8-10 years and has been proven over and over to be an excellent, MDS friendly cam with lots of low end torque and good street manners. It's made by Comp. Cams, but I don't know who the current vendor is for this grind. You'd probably have to talk to them or do a search over on LXforums.com to see who sells it.

I have this cam in both my Hemi vehicles and love them both. The valve trains (valve springs and pushrods) are from a 6.1 Hemi. I also used a 6.1 timing chain tensioner which is much heavier duty. I also wanted a little more low end torque so I advanced the one in my WK by 2* for a total of 6* advance, and the one in my LX by 6* for a total of 10*. Everyone said it wouldn't work, but it works perfectly for my uses. If I ever get back into the WK again, I'll advance it the full 10* too. The LX is a beast on the low end, but flattens out around 5800-6000 RPM though. The WK pulls hard all the way up to 6200 RPM, and is almost as strong on the bottom due to better low end gearing. The extra weight (~600 lbs. heavier than the LX) and poor aerodynamics of the WK begins dragging it down the faster you go. I've added the SRT body kit and lowered it to try and help this a bit.....drag coefficient is reduced from 0.41 to maybe 0.37-.38. I've had the Jeep up to 137 mph and it's still pulling strong at that point though.

The fuel economy on both (with headers and cam) has improved quite a bit....~25% on the WK and ~ 15-20% on the LX. The MDS on both (on the highway) is now active 85-95% of the time. On level ground it's easily over 90% active time. On the highway, I now routinely get 22-23 mpg with the WK and 26-28 mpg with the LX.

Hope this helps you a little.
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Old 10-24-2016, 11:21 AM
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Re: 5.7 Hemi Engine Mods

Great info. I just grabbed an 05' WK 5.7, and plan to add mods.

Thanks!
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Old 10-30-2016, 10:57 AM
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Re: 5.7 Hemi Engine Mods

Can someone link me to the American Racing headers that fit a 2005 WK 5.7? I can't even find them on American Racings -> Shop/Products link.
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