Hemi mods

[CB3]

You will see from the rest of this post I am not a mechanic. Bear with me, please.

Any comments would be appreciated. I would like to do some of these mods and avoid going the chip route--except perhaps to change tranny shift points. I tow a 20' boat on a double axle trailer up and down mountains at 4-7,000 feet altitude with lots of gear and 5-7 people in the vehicle. I would like to maximize power. Not interested in racing.

I had a parts counter person recommend putting a throttle body spacer on my 5.7 Durango. He said a friend did it along with a drop-in K&N filter and got a noticeable increase in peformance--more responsive throttle.

Then another guy said it would not work with the Hemi because of multi-port injection. I'm lost. One mod at a time is the best way to go, I know, so I can determine what really works. I know more intake air gives a measureable boost from doing so with my '98 Durango. I have ordered the K&N Air Charger intake kit and will also be looking at freer flowing exhaust.

Also, I see the "Fastman" ads on the home page about throttle bodies for magnum engines. I did not see a 5.7 Hemi listed. Is this another mod to consider? Possible?

TIA CB3

[CB3]

Dan "Fastman" replied quickly to my queries. According to him, the stock Hemi throttle body is about as good as you can get, and a TB spacer is useless.

[jtanwanteng]

spacers only work on engines that have injectors above where the spacer goes, or in carbuerated engines. IF and when a chip comes out, it will probably offer the most noticable gains. Other than that, you can go with the new K&N kit and an upgraded exhaust (headers, pipes, muffler)

[CB3]

Thanks, that helps me understand.

[CB3]

I am grinning ear to ear. Both these aftermarket parts were designed for the 5.7 Hemi, and they improve performance. Worth the $650 total I paid.

The sound now at idle is just a little louder than stock. The roar on full throttle is loud, but subsides as soon as you let off. I like it a lot. The K&N air charger adds quite a bit of noise on acceleration. I put it on about 500 miles after the Flowmaster with a straight through bullet resonator. If acceleration noise stock is 75 db, it is probably now about 90 db.

I drove through central and southern Utah to Lake Powell and back on Thursday. This is a great vehicle on the road. Comfortable, handles well, feels secure. The ride is definitely softer than my previous '98 5.2, and gas mileage with the Hemi is actually a little better than with the 5.2.

Top end at 4,500 feet above sea level was 114 mph, but it was only turning 4400 rpm so there must be a limiter on it. When you punch it at 75 mph, it drops from 5th to 3rd gear and roars up to 80 mph, shifts, and roars again heading quickly for 100 mph.

There are a lot of hills on the way to Powell. One mountain pass goes from about 4,000 feet to over 7,000 feet, so I expected to be burning up the high octane fuel. I averaged 76 mph over 244 miles (3 hours 11 minutes) and got 14 mpg. On the return home I took it a little easier and drove four hours with mpg @ 16.2, still averaging over 70 mph. I did not have the K&N in yet. Valentine radar unit never went off.

I have 20" wheels with wide tires, siped, and I found the ride quiet and firm, but not jarring. I have no regrets over any of the mods.

I love this car. One of my sons cautioned me not to buy another Durango because, "The new ones look like a minivan with that sloping front." I agreed at first, but all the other features of the Limited and the excellent price incentives got me hooked. :SPIN: With the dubs and peformance sound, no one is accusing this rig of looking like a mini van. I have had strangers and friends stop every day and compliment the car, often mentioning the Patriot Blue color, in parking lots and even in traffic. The Molten Red is gorgeous also, but my other Durango was red and my sports car is merlot, so I thought I would get something different. My boat and trailer have the same blue accents.

The Infiniti sound system is great. I had a Rosen 10.4" DVD player installed with an inverter for hooking up video games. Four wireless headphones, but it also plays Surround Sound through the FM radio.

Pride of ownership is high. My wife likes it, too.

If you are on the fence about getting one, I hope this very positive report will help persuade you. The two reprint articles from Motor Trend (March) and Car & Driver (April) that my local Dodge dealer gave me helped too. See also: http://www.caranddriver.com/article.asp?section_id=3&article_id=7693&page_number=1

Questions & comments welcome. Thanks for reading my ramblings. CB3

[dodgeatheart]

My personal style doesn't coincide too well with your rim choice, but I have to admit, it does look pretty good, especially on the Patriot Blue!

A good looking vehicle and write up! I see how so many people complain about fuel mileage with these Hemis, but I've had nothing but good things to say.

I had a 2002 Dakota Quad Cab 4x4 with the 4.7L V8. I couldn't get much more than 13-13.5 MPG combined city and highway in that thing. I'm averaging around 14MPG in my 5.7L Hemi Durango, and I haven't hardly hit the highway yet. I'm thoroughly impressed with my Durango so far. I've even gotten used to the front end!

[durangorod]

CB3 I think that's a hot ride you got. How wide did you go with the wheels? I'm loking to buy some 20's myself but online it's not easy to find. And I know that going to the shops is just going to leave me with questions about how wide to make the wheels without fear of rubbing. ~Durangorod~

[CB3]

Wheel width = 9" Tire width = 11", no rubbing, even with the tight turn radius. Les Schwab mounted one up on the front and checked it before selling me the package. Original wheel is 8" wide. CB3

[biged6464]

Sweet ride, here's some pics of my Durango

[jtanwanteng]

hey biged, is the K&N significantly louder than the stock intake?

[biged6464]

So much louder it's amazing, only on hard acceleration though...I just put it on Sat. so I'm still putting it through it's paces. when in park you only hear the high pitch whistle of the filter sucking in air, but when in drive and actually moving it roars is the best word i can think of, great mod!!!

[CB3]

BigEd,

Beautiful. Grill looks great. I busted part of my air temp sensor when I installed the K&N--should have used a little soapy water to insert it in the rubber grommet. Still works, but I am getting a new one.

Tell me more about the need/performance for the PIAA headlamps. Worth the cost? CB3

[biged6464]

Thanks CB3, I was a little wary during the install of the air temp sensor, I have always heard about the fragility of those suckers, I have heard it's only like a $5 part. The grill is courtesy of Jimbo who you find on this site, we met this weekend and installed it and the Aircharger.
The PIAA's are great! very pricey though, I spent $100 on the HB4's for the fogs, $20 for the sidemarker/turn signal bulbs, $20 for the back up bulbs, and $10 for a single license plate bulb (the shop broke a pack for me). I paid a premium being I bought them from a custom car shop, cheaper via the internet for sure. I like them though, at night I can use the fogs alone and they light everything up. I used the Xtreme White line
Your rim/tire package are sweet!!
Tell me more about your exhaust, that's my next step as soon as I find a shop I trust!!

[CB3]

A parts counter guy at a local Pep Boys recommended an old timer who specializes in mufflers/exhausts/brakes and who is a Flowmaster dealer. I went to him and he knew right away there was a special Flowmaster made for the Hemi. He ordered it in from Salt Lake and put it in that afternoon. It is about 1/2 the size of the stock box, which is HUGE. Also put in a straight through resonator and stainless steel (not chrome) tip. Muffler was $210. Total was $279 w/tax including labor and all the piping.

Sound is great, and added in with the K&N, this thing roars front and back when I get on the gas, but it is not disturbing either at idle or normal cruising. Just right. CB3

[biged6464]

CB3,
that is exactly what I'm talking about!! I need a reliable, skilled exhaust shop that will do quality work. Try and find which muffler you used, and why the resonator?? I've never used one in my previous exhaust systems. I did see how monster the stock muffler is, probably again to keep noise in the cabin down. I do like the fact that it only roars when stomping on it, my days of being loud everywhere I go are over, I need some creature comforts, not the constant drone I used have in the cab of my Dakota no matter what speed I was going!! If you could let me know the part numbers, etc. (single in, single out??) that would be great!!

[CB3]

53073 Flowmaster BB11 Muffler Single In/Out ($180)
A-18 AST 2 1/2" Resonator Muffler ($45)
3009A Stainless Tip Bullet ($32)

The resonator replaced the stock round can resonator mounted near the rear bumper. The new one has a thinner profile and does not hang down and visible like the stock unit. The muffler is in front of the rear axle. CB3

[biged6464]

is the resonator needed?? is it for reducing noise?? I ask because I have never used one on my previous exhaustg setups. thanks! Did you contact Flowmaster as to which muffler is the best match for the Hemi?? I have heard that they had a certain muffler for the Hemi Ram...is that the one you got??

[CB3]

I don't know the answers to your questions, but I suppose:

JR put the resonator on because one was there in the first place, and I imagine it does help keep things quiet when you want thenm quiet.

I did not contact Flowmaster because JR knew there was this specific muffler for the Hemi. After checking in his book, he contacted the regional Flowmaster distributor and had them put it on their truck for the day. I would imagine it would be the same muffler for any application of the same engine, but I don't know. CB3

[biged6464]

CB3, that's good enough of an answer for me!!! thanks for the info and I may buy the parts on my own and then go to a shop w/ them and go from there

[CB3]

Further investigation today at the Flowmaster website and from a brochure(http://www.flowmastermufflers.com/cgi-bin/flowmaster/53073.html)
show this Model 53073 is a standard Series 70 muffler for big block engines producing the mildest (quietest, mellow) tone available. The 30, 40, 50 and 80 seires (especially) are all louder. This is quiet when idling or not accelerating, but it has a wonderful sound when you punch the throttle. I imagine other Flowmasters will fit the Durango because there is plenty of room under there after removing the big stock unit, but this is the most quiet, and that is what I asked for. It is not exclusive to the 5.7 Hemi, but it is apparently what Flowmaster recommends. CB3

[Toneaero]

You guys ever heard of a muffler called the "aero turbine"? Supposedly its the rave for the new 04 hemis according to other forums. You can check them out at www.aeroturbine.com They also have a link that lets you hear what a 5.7 hemi would sound like with this muffler. Sounds pretty nice but I think id rather get a cutout instead.

~Tony~

[dodgeatheart]

Nice advertisement there, Tone...

[Toneaero]

Sorry, didnt mean to. I have no affiliation with them at all. Just curious on what you guys thought. Im in the market to hear the hemi rumble.

~Tony~

[CB3]

That aero turbine link only leads me to jet engines, no mufflers. What am I missing? CB3

[biged6464]

CB3 and co.,
I still haven't gotten my exhaust installed on my Durango, haven't had the time on a weekday when I know most shops will be open to go look around and see which operation looks legit and not, who bends pipe, etc. I think I am going to order the muffler itself direct from Summit or someone and bring it with me for the install, I have a feeling any local shop won't have such an intimate relationship w/ the local Flowmaster distributor like you have CB3. That way I'll know I have the right part.

I've done some homework on resonators and I basically think the only purpose it serves is sound deadening, so I'm going to go without one. as for the location and style of the exit/tip I'm up in the air...not much room behind the rear wheel to get creative

[Kolohe D]

Where did you purchase the AST resonator?

[biged6464]

After doing some more reading the resonator on any vehicle is put there to quiet things down and in the process rob some horsepower. I'm going to opt to go with no resonator, the factory put it there to quiet down the mighty HEMI, it is our job to awaken this sleeping giant!! You spent good $$ on the HEMI upgrade, don't you want to hear it...I'm sure it won't be unbearable being it is exiting so far behind the front seats, there is still a cat in place, etc...thoughts??

[hemibass]

biged what state you in . if you are in mi theres a place called d&s motersports best welds i have ever seen


chuck

[biged6464]

I'm in FL unfortunately, home of the fly by night auto accessory companies and shops!!

[CB3]

I purchased the resonator and the Flowmaster from my local exhaust/weld shop, JR's Mufflers in Orem, Utah.

I just returned from an 850 mile round-trip through Southern Utah to Lake Powell towing my 20' boat (lots of major elevation changes). I can guarantee you I would not want my Hemi any louder than it already is. When it drops to second to pull up an 11 degree slope, you cannot even converse because of the roar. Third gear requires elevated speaking volume, and top gear is just nice.

For some of us, there is such a thing as "TOO LOUD!" and for me, that would be the Flowmaster 70 series without the rear AST resonator. CB3

[biged6464]

CB3 thanks for the reply. I really may reconsider my logic on the resonator. I am definitely not a teenager anymore so a more refined sound may be my answer. The exit location and style are my biggest hangup: dual rear side sweep, duals out the back, single in/single out muffler, etc.
I definitely don't want a constant drone at highway speed. I used to have '95 Dakota w/ the 3.9. I went with a single in/dual out Flowmaster, cut the cat off, 2.5" custom bent pipe. The drone on that was mind numbing!!! I have Thursday and Friday off this week, I hope to go visit some shops then.

[piimauna]

What model Flowmaster are you using? Series 70?

[biged6464]

I'm prettty sure that is what CB3 is using.....that is the Big Block II 70 Series that Flowmaster recommends for the Hemi....I may go with something throatier...I need to call Flowmaster up and pick their brain

[CB3]

Yes, I installed a Series 70 Flowmaster, single in-out piping (dual is available) with an AST rear resonator behind the rear axle. Just enough noise for me. There are times under full acceleration, going uphill (6000' elevation), towing the 20' ski boat, when it is loud enough that you really cannot converse. The rest of the time it is either a good throaty roar or a nice purrrrr, at idle and not under acceleration there is just enough noise to know it is not stock, but not at all bothersome. CB3

[piimauna]

Thanks, my friend installed a Ravin muffler with dual exhaust out the back. It sounds nasty, especially under full throttle, but for everyday driving it is just too loud. Maybe give the series 70 a try.

[biged6464]

There is a guy by the name "epowell" on here that went with a trud dual muffler setup coming off of the factory headers with duals out the back...it is quite a feat that his muffler shop was able to fit the piping around the spare, etc...he sent me some detailed pics so I am going to try and mimic his setup using Flowmaster's instead of the Magnaflow's he used

[epowell]

Thanks BigEd. I have had a couple of requests about the system and have a detailed e-mail message with photos, questions and answers asked of me, etc. that I have sent to a couple of people. If anyone else wants it, send me a PM with an e-mail address and I will send it to you. It may not be for everyone and many may simply be happy with changing the muffler and getting rid of the rear resonator mufller or going with a "canned" cat back exhaust, but I have been very please so far with this system in combo with the CAI. Some may not like the exhaust tips I chose, but you can always use a different setup on the tips or change the piping arrangment downstream of the mufflers to side exits, corner exits, or so on.