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Intake and Exhaust manifold swap on 2.7

19K views 56 replies 14 participants last post by  Farmboy88 
#1 · (Edited)
Pics throughout post. Scroll and you shall see.

I was psyched to find a complete Charger/Magnum 2.7 intake and the exhaust manifolds on eGay for cheap. Its great when someone doesn't list an item correctly.

For those who wondered if the Charger intake would fit under the hood, it doesn't. But it will with a little help.

For those who wondered if the Charger exhaust manifolds will fit, they will. Of course you'll need to modify the down pipes. (They will definitely require moving or deleting the stock cats)

I have my engine, and car, ripped apart for the normal high mileage maintenance.
  • timing chain
  • water pump
  • valve seals
  • oil pan gasket
  • front brakes
  • front bushings
  • front struts
  • front bearings
  • sub frame bushings
  • and the cooling fans burned up

I'm also doing the exhaust while its apart. True 2 1/4" duals through a homemade muffler and Flowtech Purple Hornies in the back. O2s, plugs, coil boots, thermostat, ect. May replace the oil pump.

The original tie-rod ends and ball-joints are still in great shape. I'm not replacing factory joints if they are still good. The original cv shafts are still fine too. I just had one apart last summer for a ripped boot and it looked great yet.

Back to the intake and exhaust. I'm not looking to make more power. It is a 2.7. But if I can make it more drivable and get some more gas mileage out of it... Plus the exhaust will definitely sound unique.

The exhaust is self explanatory. Look at the stock log manifold. It has a tight u-turn in it. The charger manifolds are a real tri-y style. They flow much more smoothly out of the head and down to the collector. I'm also taking out my burned up cats. I'll put one on later. That'll free up a lot of restriction in the exhaust.

The intake, well, its crap. Its designed for high rpm flow. How often are you driving around at 4k rpm or higher? The charger intake has really long sweeping runners. This allows more low end flow when you hit the gas. The log chamber with a long run from the throttle body will also aid in low end. The reason Chargers have "less power" is because of the intake they use. They basically took away from the peak hp, and gave the engine a broader torque band. So this makes the car more drive-able.

Few issues you run into with the intake. First, the butterfly valve on the end will need to be taken out. Second, the hood hits. Its not as bad as it sounds. If I chop the front of the intake and epoxy a cap on it, it should clear. The worst I have to do is slice a brace in the hood to gain more clearance. The intake also just barely touches the bottom edge of the cowl. Taking a rib off the intake and maybe a few good whacks with a block and hammer to the cowl will clear that up. The biggest issue is probably the throttle body. The charger throttle body is drive-by-wire. I'm not fitting an electric throttle into this car. I dug into my pile of throttle bodies and found an exact fit. A tb off of a '98 Ford 5.4 bolts right in place. No modifications. Its 70mm with a tps on the opposite end. It also matches the bore of the intake. I already found the stock tps and the ford one use the same values so its just replacing the connector on the stock harness.

Pics coming soon.
 
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#5 ·
Damn straight I would! I couldve sworn somebody said that theres no clearance which is why Im trying to adapt 1G 3.3 headers on mine. But if you found out that they fit, well damn! I will be keeping my plenum though, lol

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#6 ·
Thinking what I read over, what are the major "losses" in power with the charger plenum, top speed or just pick up?

May just do what Sqully's doing and pimp my 2.7 versus dropping a 3.5 in.. With gas jumping in prices the 3.5 looks spookey. Ironically, I found a 03 3.5 for my car the other day for $500.
 
#11 ·
Loss in peak HP on paper. Look up the numbers for Intrepid/Sebring 2.7s and the Charger/Magnum 2.7. I was getting 30mpg average before I ran cleaner through my engine and it started to really burn oil. If that 3.5 is complete and ready to go, I'd jump on it too.

Here they talk about the numbers change http://en.wikipedia.org/wiki/Chrysler_LH_engine
Which is because of the different intake and exhaust they put on the engine. The rest of the engine is the same, except for a slight boost in compression on the LX platform.

You'll see the talk about sludge in the lower part of the page. I have plans for this as well. A catch can for the breather set up and doing away with the EGR. I also thought about doing a crankcase evac set-up. Just want to eliminate anymore oil getting sucked though the engine. Its pretty nasty looking.
 
#9 ·
Im not doing it for efficiency. Im doing it for sheer uniqueness, which has been a staple of my car since I got it. Im the first one to run a Special PCM with a 2.7 and i would like to be the first to moderately beef one up too.

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#13 ·
*stolen directly from allpar.com

"In 2004, the 2.7 liter engine was modified for the LX series to produce more low-speed torque at launch and during mid-range operation for strong performance in everyday driving. The engine produced 190 hp at 6400 rpm, and 190 lb.-ft. of torque at 4000 rpm. This was done by using a new active dual-plenum intake manifold tuned for improved low-speed torque.

The manifold included a manifold tuning valve added to low-speed torque — increasing part-throttle torque by 8-10% in the primary driving range of 2100 to 3400 rpm, giving better performance in normal driving; and also adding to torque under full throttle. "
 
#14 ·
Well, I have the intake from a Magnum so it did come with the tuning valve. Can't be that hard to wire to a switch inside. But, theres that damn hood clearance problem. This is with the valve off.





What the hell. I'll chop the hood. I looked around for hood bumps to weld in with no luck. So, I'm deciding on a differential cover to make the bump. It'll end up looking like the DSM bump. Hey, they are cousins. Theirs is to clear the timing belt, mines to clear the manifold tuning valve(that does sound a little gay).

I've had bad luck getting to working on this damn car. After I'm done typing this I'm back at it.
 
#17 ·
I will say that it definitely looks better than the soft pretzel intake. Ill keep an eye on this thread, not too many people actually want to mod a 2.7. Oh and BTW, the LH isnt related to anything Mitsu whatsoever. Common misconception amongst Mopar greenhorns, lol

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#18 ·
Didn't say it was related to it. I know the engine has nothing in common with the 3.0 or any other mitsu. But Dodge and Mitsubishi have a history together. And the DSM bump is on their number one ricer here in the states.

Another $100 in the engine. The oil pump is scored. And other $100. Half of the lifters(lash adjusters) are so full of crap they cant even be forced to collapse. I've had them soaking for a couple days. Otherwise, the cams, and bearing surfaces, looks awesome. So, the intake and manifold swap isn't the money into this damn thing. But its either fix this car once, and have a nice car for a long time, or buy another car in half ass shape and have to fix it later.

On another note, no exhaust shop can make the flange for these manifolds. Its an odd angle. So, I need to find a junkyard donor for the flanges.
 
#20 ·
Got my custom muffler finished. Did a lot of engine work and have all the suspension and brakes back on the car.

And never did get flanges made. Instead I welded pipe straight to the manifolds. I left a lap joint on both sides that will serve as a place to disconnect and remove if needed. I've got the manifolds and down pipe pieces welded up. Still need to re-add the rear o2 sensor bungs. I want to put them in with extensions(move them out of the exhaust flow) and try to keep my engine light off.

The intake got chopped. My donor plastic all turned out to be useless when I went to cut. So a piece of thin stainless was cut out, screwed on, and sealed with RTV silicone. I had to chop a decent sized piece off the intake where the tuning valve would have been. I also had to remove 1 brace out of the hood. There is now over 1/4" clearance.

Still to go:
torque suspension parts
reattach pulleys and accessories
finish exhaust behind muffler
plumb in and attach remote oil filter and cooler
finish intake set-up including throttle body and swapping a couple sensors
reassemble front clip

I forgot to mention I got such a great deal, that I couldn't pass up, on a remote oil filter kit and a nice engine and trans cooler combo. Its a 6 pass oil, 4 pass trans cooler thats about 17"x12".
What kills these engines? Sludge
What makes most sludge? Heat(and bad seals/pcv systems)

Oil/Trans Cooler
Filter Relocation Kit

Did have to get some 90 degree elbows for the adapter that goes in place of the stock oil filter. I would be dragging hoses on bumps if I didn't.
I'm getting close to being done. I always seem to get tied up in something else though. And yes, worthless without pics. They will come.
 
#22 ·
Pics will be posted later today. I've been tied up again. Always fixing something else or spending time with someone else. Anyways, I'll get the exhaust bolted in later today for the final time. The crank evac is complete and welded in. I also did a little more searching on evac vs. pcv. Appears I can run both. I'm going to install an oil trap, and just T off to both the evac and the pcv valve. Benefits would be constant breathing of the engine block. The pcv only works under vacuum, or idle to light throttle, while the evac system works under heavier throttle. I'm going for a 0% oil consumption.
 
#23 ·
Heres the exhaust manifolds all welded up.


The oil filter adapter block with fittings installed.


The chunk out of the hood brace.


And lost the other pics, so I'll take them again and post them later. My camera is junk and deletes pics when the batteries die.
 
#24 ·
Man, putting this thing together is fun. Theres a nest of hoses all over the engine bay. The evac and pcv hoses and the coolant hoses all come back to the driver side rear area. Plus the extra hoses up front for the oil cooler and remote filter. Theres lines everywhere.

I goofed up my exhaust and welded the passenger side wrong. Had it aimed at the sub-frame. Spent a little over an hour fixing that. Exhaust is done to the muffler.

And I do need to trim the sheet metal connecting the strut towers. I thought the intake would clear, but it is just against it. So cut, flip, and weld.

Still need to attach accessories, modify and extend a couple plugs on the harness, and get the radiator/cooler buttoned in.

I wont have internet for a few days, so next update will be later this weekend when this thing should be on the ground and running. YAY!
 
#26 ·
The ground on the passenger side needs to be relocated, and a little grinding on the manifold to clear the same spot on the driver side. They aim straight down towards the cv boots. So your best bet is to grab the original flange off a Charger/Magnum and put a sharp 90* bend right on it to go up and over the cv. I've got mine in but my internet is shutting off here any minute so no pics to post yet.
 
#28 ·
sickness sickness sickness sickness sickness!!!!!!!
 
#30 ·
So close. Something always comes up... always.

Anyways, got a lot more done. I also snapped some more pics. I like taking pics of my old vehicles to remind myself what they were and what I've accomplished. I'll share a few.


The muffler

The radiator with cooler attached

The hacked up intake with a ugly patch over the front

Modified throttle cable bracket and the Ford throttle body

MAP and IAT sensor located

CLEAR!

Exhaust pics


pass side over the cv

driver side over the cv

muffler again, and showing stock outlet location of modified down pipes

shiny new parts on the front end

relocated oil filter

a little something I whipped up


cant even tell its there


Hit a point that bummed me out earlier. I don't have enough 1/2" oil cooler hose. 10' goes quick. Its not a "go to the auto parts and get it" kind of item. No one around carries it. I have to go to a custom shop to get it.
 
#33 ·
Yes, its a oil catch can. I think I spent about $25 to make it. Its fairly large, it fits, and its cheap.

A lot of my work may not look pretty, but it all functions like its supposed to. I'm go before show. I plan to get some more small wire loom, and do something different for that cover on the intake. But I want this thing going.
 
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