Performance for the 3.9
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G
Guest
·Well, theres a ton you can do.... I would start with some of the basics like so:
*change your plugs to the Autolite 3923's, they run a degree cooler than the stock plugs and make a big difference. Also, change your cap & rotor with a Accell or Borg Warner Select cap & rotor. These have brass contacts and help put more current to the plugs. If your plug wires are ok, leave them....otherwise any 7.5mm wire will do just fine.
*Install an 180 degree thermostat. This will keep your engine cooler and deliver more HP.
*Install a cold air intake. Basicly, a cold air intake will deliver more & cooler air to the engine. Cold air intakes are pretty cheap. I use a Spectre intake for a Honda Civic that I found at Auto Zone....They fit and work EXTREMELY well. and for $50, you get an intake that looks a lot better than a homebrew and will give you some real gains
So if you've got $100, and want to add 10-15hp, I would start here, then work up to more serious mods like headers, cat-back exhaust, throttle body, etc....
If you really want to jump in, I have a used F&B 48mm Throttle body for sale (look in the for sale fourm)
I hope this helps.
*change your plugs to the Autolite 3923's, they run a degree cooler than the stock plugs and make a big difference. Also, change your cap & rotor with a Accell or Borg Warner Select cap & rotor. These have brass contacts and help put more current to the plugs. If your plug wires are ok, leave them....otherwise any 7.5mm wire will do just fine.
*Install an 180 degree thermostat. This will keep your engine cooler and deliver more HP.
*Install a cold air intake. Basicly, a cold air intake will deliver more & cooler air to the engine. Cold air intakes are pretty cheap. I use a Spectre intake for a Honda Civic that I found at Auto Zone....They fit and work EXTREMELY well. and for $50, you get an intake that looks a lot better than a homebrew and will give you some real gains
So if you've got $100, and want to add 10-15hp, I would start here, then work up to more serious mods like headers, cat-back exhaust, throttle body, etc....
If you really want to jump in, I have a used F&B 48mm Throttle body for sale (look in the for sale fourm)
I hope this helps.
G
Guest
·Raging, you got any pictures of that Spectre intake??
G
Guest
·any of the bolt-ons listed will help, also consider electric fans. I've got em' and picked up serious gas mileage. They also scare the cat when they come on
-miggity
-miggity
Joined
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65 Posts
When you go to the gas station next time, put 96 octane in itwith an additive used in crochrockets. Friend of mine did that once and........well........he don't got a ride now, nm bad idea.
G
Guest
·Theres a pic of the spectre intake on my site at http://garysdakota.1colony.com/truck.html Just click on the engine pic and a bigger one will show up.
BTW... I have seen the 3.9's actually suffer performance wise from running high octane. When I first started taking the truck to the strip, I was filling up with 93, and ran 17.6's But then one time I filled up with 89 and ran 17.2's
The stock 3.9 does not have a high enough compression ratio to fully utilize 93 or higher fuel. Stick with 87 for daily driving and 89 for the strip... just fill up at a shell, mobil, or BP. Stay away from the discount gas stations!
BTW... I have seen the 3.9's actually suffer performance wise from running high octane. When I first started taking the truck to the strip, I was filling up with 93, and ran 17.6's But then one time I filled up with 89 and ran 17.2's
The stock 3.9 does not have a high enough compression ratio to fully utilize 93 or higher fuel. Stick with 87 for daily driving and 89 for the strip... just fill up at a shell, mobil, or BP. Stay away from the discount gas stations!
Joined
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65 Posts
yea stick with brand named gasses. there's only two types of gas stations within a 30 mile radius and thats a Hess and a "Safe-Way" gas station which is owned by Safe-Way Foods.
G
Guest
·if i get the 180 degree thermostat, don't i need to "re computerize" the engine to acknowledge the change or will it automatically pick it up?
G
Guest
·My stock 98 3.9 RC 5-speed ran 16.8 @ 80 stock.
G
Guest
·#1939 Headers
I can't use these 3.9 v6 headers. Mine has the 3.7 in
it. Rather than send them back, anybody want them
for $359.00 plus you pay shipping I am in Florida.
[email protected]. or 813 788-0696
Bill OParowski
I can't use these 3.9 v6 headers. Mine has the 3.7 in
it. Rather than send them back, anybody want them
for $359.00 plus you pay shipping I am in Florida.
[email protected]. or 813 788-0696
Bill OParowski
G
Guest
·Headers
They are JBA Headers Nickel plated. but the number is #1939 that you can look up and make sure.
Thanks.
Bill OParowski
They are JBA Headers Nickel plated. but the number is #1939 that you can look up and make sure.
Thanks.
Bill OParowski
Joined
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298 Posts
what kind of gas mileage do you guys get? I'm getting around 16mpg in regular driving. I have the Airaid intake and dynaflow exhaust as well, but it doesn't seem to be helping me any. I have a 1997 dak extended cab. Don't know if it is a 3.7 or 3.9 I also have new plugs and wires and rotory on it. The filter is dirty, but that shouldn't drop my mpg should it?
Joined
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285 Posts
You have a 3.9, and a clean filter is always better than a dirty one.Bigguy18LSU77 said:
On a FULL tank of gas, in my 97 V6 RC....with alot of highway driving.......I get a whopping...............240 miles.........if I'm lucky!!
240 miles on a FULL tank of gas, and I hardly get on it either.....oh well I guess.
Joined
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298 Posts
What really gets on my nerves is that my mom has a 99 GMC 5.3 Liter 350 and she gets 22mpg. And I have a 3.9 liter and get 16mpg. That's just not eve right. She has more horsepower AND better gas mileage.
G
Guest
·I have an '02 3.9 and in conservative driving i get around 22-23 mpg. I think the most miles I've had out of one tank are 420 approx. I guess I get pretty decent milage.
Joined
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51 Posts
gas mileage!!!
I get about 22-23 mpg on the highway.
The most i have squeezed out my truck is 400 miles on a full tank of gas.
That's with a 3.9L with an Air Raid intake, JBA Headers, and cat back exhaust system.
I also stick between 60 and 65 mph on the highway. Anything above that and your gas mileage drops way off.
I get about 22-23 mpg on the highway.
The most i have squeezed out my truck is 400 miles on a full tank of gas.
That's with a 3.9L with an Air Raid intake, JBA Headers, and cat back exhaust system.
I also stick between 60 and 65 mph on the highway. Anything above that and your gas mileage drops way off.
Joined
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1,413 Posts
my v6 is stock, best i got out of it was 22mpg on road trip dong under 70mph on the highway. conservative city driving gets me around 15~17mpg. farthest i've ever dared to go on a tank was 302 miles. get gas lights up at 200 city / 240 highway, usually takes at least 16 gallons to filll up the 22 gallon tank.
when i'd cruise 80mph on the highway my best was always 16mpg.
when i'd cruise 80mph on the highway my best was always 16mpg.
man with my 22 gal tank i always take it down to the red line and get between 320-340. once on a good trip i got 397 but that was all highway with a some idiling (i was delivering lost luggage at the time so it was with bags in the bad also) and have never put in more than 20.75 gal. so it has a "reserve" of 1.25 for idiots who try to use it past the E line.
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