5.0 mileage

[freak007]

Hello all, I recently purchased a 97 Mountianeer for my wife, it is AWD with the 5.0. I drove it for 2 1/2 tanks before I had to come back to Iraq, and I was getting 14-16mpg out of it. I realize that this isn't too bad because I do have a heavy foot, however I used to have a 95 F150 4x4/auto that would run 17-20... SO I want to tweak a few more miles per gallon out of her... I would like to get it to 20+ with me driving... The truck has 100K miles on it, before I left I gave it an oil change and a new fuel filter, air filter was still like new so I left it alone. After I get back I will be giving it a new set of plugs/wires, but I was also thinking a CAI and cat back exhaust would be beneficial... Headers are also planed for the future... I am looking to spend ~$500 initially...

For exhaust I have to keep it quiet, a slight rumble is fine. This is the wifes truck and she insists it has to be reasonable (as do I) because we also have a young son who rides in said truck. In the past I have been very happy with Dynomax Superturbos, they flow very well and are a mellow sounding muffler, I see that Dynomax does offer a cat back kit for my truck... does anyone have any experiance with this kit at all? Any other suggestions? Please do not even suggest Blowmasters. I hate them, I hate their sound, I hate their price, and to top it off and they are by far one of the most restrictive aftermarket mufflers available (I have the flowbench results to prove it too), yet they seem to be very popular with this crowd...

What about intake, I see many of you are running tha MACs kit, how much better is it than a K&N for a stock engine? Any other suggestions?

The one thing that has me really thinking is the headers, looking at my stock manifolds I could see they were a poor factory excuse for a header, would I see a better gain by swapping out the stock manifolds for a set of headers and leaving the rest of the exhaust/intake for the time being? What about the FMS vs TorqueMonster debate? IS ther going to be enough of a differance in a stock engine to justify the $300 extra for the TM?

Any other tips to improve my mileage? I am all ears...

 

[tktrain]

Man did you ever open a can of worms... You are going to get one heck of a lot of debate and personal opinions.

I went with the FRPP (Motorsport) headers back in 1998 since they were the only game in town at the time. With a little massaging with a torch and some die grinder work they are a big improvement over the stock pinch tube manifolds. In fact, I spent about 2 1/2 - 3 hours getting mine ready to install. If I were doing it again today, I'd opt for the TM's. In fact, I'm debating getting a set of TM's and selling my FRPP headers.

For mileage, I'd start by putting synthetic fluids in everything: Transmission, differentials, transfer case, as well as in the engine. For the muffler, personal preference should be your guide. I'm running a Walker Dynomax dual 2 1/2" inlet 3" single outlet with a custom bent 3" tailpipe. Also, my rear cats mysteriously disappeared one day, that made a big difference in overall feel (it surprised me how much).

 

[lowflyingbird]

Hi,
I just finished my manifold install. I had the same crimped stainless ones you have now. They are the absolute worst!! I did not have the money for TM headers, I bought the 99-01 cast manifolds really cheap. Let me tell you the cast parts are a big improvement over the stainless!! Just like TKTRAIN, my rear cats also dissapeared one day??? I also have a set of 1.7 Crane rockers, K&N filter, and the 1" intake spacer, all well worth the money.
All fluids changed to SYN. a definate plus. and a 2 1/2" Dynomax super turbo cat back. That does have a little rumble to it, the 2 1/4" would have pleased my ears more.
NOW SINCE THATS OUT OF THE WAY, Its blower mock-up time on my extra engine!! YEAH!!!
I will reply again with some fuel economy numbers when calced.

 

[freak007]

I was also planning on synthetics in the driveline... but not for the engine yet, it has a slight leak I need to track down and fix first...

TK - did you see any improvement in mileage with the exhaust mods you have?

are the stock pipes 2 1/2? I was under mine and I thought they looked smaller...


LFB - please tell me more about the cast manifolds...

 

[Turdle]

I must second the sythetic suggestion. It was the greatest improvement overall.

With the Amsoil in all locations, I noticed much less rolling resistance.

5.0 engines made in late 98-01 had cast exhaust manifolds, which I believe have better flow, and last longer then the tubular counterparts.

FMS headers are a waste of time!!. Unless you give them a good $200 ceramic coating treatment, they will corrode in a few years.

I am glad you joined us--BTW.
It will be nice to watch the improvements.

 

[lowflyingbird]

Hi,
First, I was only going to change my cracked stainless OEM manifold. But, after removing it I saw that all the pipe to head flange weld is internal. This makes the port the size of a small peanut!! Then I saw that the manifold was actually stamped and welded plate versus pipe, so their are welds all over the place. Also some runners go past their welds running into the streem of other cylinders flow. The cast manifolds have Head size exhaust ports. They are much more open and eliminate much of the sharp corners that the stainless ones have. I did a bit of dremel work on the cast pass. side manifold, but barely any dremel work to the driver side. running the truck now shows a definite improvement. I got my manifolds on Ebay, New they cost me about $100. for both incl. shipping. I had time to hunt around on Ebay, but I do still see people trying to sell individual manifolds for about $135. I think thats a rip off.
If you cant spring for torquemonsters, and you have the OEM stainless manifolds, I cant recomend strong enough to get the cast ones.
Keith

 

[freak007]

are the cast ones a bolt up fit or do I need the later down pipes also?

 

[Turdle]

Hi,
First, I was only going to change my cracked stainless OEM manifold. But, after removing it I saw that all the pipe to head flange weld is internal. This makes the port the size of a small peanut!! I cant recomend strong enough to get the cast ones.
Keith

I have a set of tubulars in garage--#3 port is so small, I cannot stick my index finger through it.

Cast manifolds will bolt right on---

 

[freak007]

These what I need? (top two)

http://search.stores.ebay.com/Parts...sopZ1QQfsubZ6QQftsZ2QQsaselZ236617029QQsofpZ0

ok final question...

Cast manifolds or FMS headers?

 

[lowflyingbird]

Yes Those Are

Hi,
Yes those cast manifolds on ebay are the ones. AND, NO you do not have to change the down pipes, They fit exactly the same, you will only need two longer bolts ,one for each side that bolt them to the heads.As for the FMS headers, I have not heard anything that good enough about them to justify their cost. Three tubes into one tube like the OEM design still blows. And I dont mean that by they flow good. So if your on a budget, go cast. If your saving for the FMS ones, keep saving and go TM, everyone swears by them.

 

[freak007]

ok thanks...

LFB - You mentioned that you had the 2 1/2" Dynomax cat back, I assume you mean the tailpipe is 2 1/2" How does it sound? Why do you think you would rather have the 2 1/4? Is the muffler a true dual in, or is a single inlet with a Y? If it is single do you know the diameter of the single?

TK - do you have the P/N for the muffler you used? looking on scummits site I can only find Dynomax with a 2 1/4" dual in 2 1/2" single out...


anyone have input on CAIs?

 

[Dan Whitaker]

Since you have a 1997 you might have to plug the EGR tube unless you have a late year built '97 with the external EGR.

 

[lowflyingbird]

Hi,
My cat back I put together is a Y into a single inlet/ outlet muffler and all 2 1/2 incl. the tail.

 

[Four0Sport]

I was thinking about droppin the back 2 cats but was a fraid of a CEL or O2 sensor problem, howd that work out for you guys? also saw some talk about plugging the egr. i was wondering about an egr delete, how to, consequences, that sort of thing. any feedback is appreciated.

 

['97 V8]

I got rid of my 2 back cats and have no CEL from it.

 

[lowflyingbird]

Hi,
DO NOT PLUG YOUR EGR, it will throw a code. DO NOT try to run the tube to a sorce of clean air, I tried it! No code, but you will get some pinging from the motor at certain loads and rpm ranges. Altering the EGR also effects fuel economy in a neg. way. As for the rear cats, If you think they are hurting you, drop them. No one on the site with a V8 has had any problem to my knowledge. I dropped mine.

 

[tktrain]

The cat fairy took away my rear cats and I got no code. There is nothing that can detect that the rears are gone, so there won't be an issue. The rear cats being gone really improved my driveability.

I concur on the EGR. Back in the 1970's EGR was a hindrance, but with the computer controls we have today removing the system will do more harm than good. Do not remove or plug it!

Jon - I've been running my FMS stainless headers since December of 1998. No problems at all with them. But I did do about 2 1/2 -3 hours of work on the welds and internal joints (that I could reach with a die grinder) and give them a good coat of the Eastwood Company's Stainless Exhaust paint before I put them on.

Freak - It's been over 8 years since I put the Walker on the truck, I don't have the part number in my file. I probably didn't ask what it was was when my buddy with the muffler shop put it on for me.

 

[Dan Whitaker]

The reason I said he might have to plug the EGR on the exhaust manifold is because I didn't think the non "P" head engines had a tube coming off the exhaust to the EGR valve.

 

[freak007]

Does anyone have a sound clip of the Dynomax cat-back on a 5.0? I am also interested in the Gibson, and the Magnaflow as I have heard these three are the most mellow sounding cat backs available for our trucks... Also where can I find the Magnaflow?

 

[titerad]

I have a magnaflow on my 5.0 exp it sounds good and not too loud. I have always used dynomax on all of my other vehicle including my 4.0 exp there is very little difference between the sound of the magnaflow and the dynomax.