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ecdak
Dodge Dakota
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8/15/2005
01:25:07
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 Subject: throtttle bodies
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I have heard lots of good things about throttle bodies. But I have also heard they can rob your low end. I have a 4.7l. what size would be best for that? anybody? Is there a balance to be acheived. Since it is a street truck will gaining on low end affect cruising the family on the freeway?
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N56629
Dodge Dakota
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8/15/2005
06:56:53
| RE: throtttle bodies
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What year 4.7? A true 68mm usually works best for all around driving. Often there are claims of lost power on the bottom end but since you are looking at "freeway" driving that won't affect you. If you do a lot of towing you might want to leave it alone or look at the SuperChips for it's Towing program.
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Kowalski
GenIII
8/15/2005
18:34:29
| RE: throtttle bodies
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If thinking bigger than 68mm, complimentary mods (cam, exhaust) could be a good idea. You'll likely get some first hand advice from others who have gone larger; I can tell you I didn't feel any loss of towing torque going from stock 65mm ('00 only) to a ported stock 68mm.
Lead, follow, or get out of the way
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MotorSport4.7
Dodge Dakota
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8/15/2005
19:01:14
| RE: throtttle bodies
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I have the 68mm TheFastMan.com TB on my 4.7L and to be honest I am all around disappointed in it. The performance is minimal if any. Gas Milage is almost 1mpg worse. I will be switching back to stock pretty soon. Though I did hear a lot of good things about this TB before I purchased it. Maybe my experience is a fluke.
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ecdak
Dodge Dakota
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8/15/2005
19:11:55
| RE: throtttle bodies
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it is a 2002 auto. I was looking for off the line gain w/o adversly affecting mpg on the freeway. probably asking for to much. Maybe another way too go would be better? I do not tow anything yet. Maybe a 20' bayliner down the road>
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N56629
Dodge Dakota
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8/15/2005
22:16:20
| RE: throtttle bodies
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MotorSport4.7, I think you are the first one that has complained about not feeling a noticable difference. It's probably pretty hard to tell the difference in ordinary day to day driving, but when you put the pedal to the metal it should be readily apparent.
Isn't it possible that there are other reasons for your lack luster performance? Also, if you are looking for a big difference in throttle response, you are not going to see it stepping into it lightly. All of the gain is on the high end.
Think about it logically. If you have a larger bore you will simply be opeining the throttle plate less to reach any given speed or rate of acceleration. The only time the rate of acceleration will change is at WOT. At less than WOT you control the rate by how far you open the throttle.
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Kowalski
GenIII
8/16/2005
16:13:19
| RE: throtttle bodies
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ecdak - the gain from a larger TB will be at the big end as the preceding post explains. Since you express an interest in alternatives, you might consider the HO cams. I see better torque right from the bottom with no loss of milage. A custom flash or chip can also provide gains throughout the range from increased ignition advance - didn't see any loss of milage with the flash I got either. Then there's also the option of going with lower gears, that surprisingly can actually give slightly better milage for some of our trucks - going to 4.10s was worth about .75 of a mpg for me.
Lead, follow, or get out of the way
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MotorSport4.7
Dodge Dakota
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8/16/2005
17:38:22
| RE: throtttle bodies
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N56629,
I'm sure I have about the same mods as most everyone. I have KRC 206 Cams. Fastman 68mm TB K&N CAI and Flowmaster 40 series exhaust. I haven't put on headers as I have not read of real gains on the 4.7L and I have not puchased the superchips programmer yet (I'm a little worried about it locking up my pcm).
I did not notice by "feel" any real gains in performance, but I haven't dyno'd or been to the track, so maybe gains are minimal if any. The Fastman TB was my last mod so far. Maybe on a stock engine, you will notice it more, but I am not impressed with it. That is just my experience. I would not recommend the 68mm Fastman to anyone. Maybe I should have went with a 70mm?
My next project will be the rear end.
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GraphiteDak
GenIII
8/16/2005
18:37:32
| RE: throtttle bodies
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Funny thing is I have done the HO cams AND ported quite a bit of material out of my stock 68MM (removing the "torque step" and then some).
There's how much material I swept up from the garage floor!
Now you would THINK I would have LOST low end grunt.
Phuck no! I can't stop from burning the tires!
And at the track I'm beating the 2WD trucks up to 60MPH but losing at the end.
Got to figure that out still.. :(
But all round it's an improvement!
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N56629
Dodge Dakota
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8/16/2005
19:36:10
| RE: throtttle bodies
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MotorSport4.7, you may have not noticed any gains from the cams if not for 68mm tb. Mods often tend to work together. Instead of dynoing your truck find someone that would like to try out a modified tb without having to buy it. That way you both will experience a real time comparison.
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ecdak
Dodge Dakota
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8/16/2005
23:10:53
| RE: throtttle bodies
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graphite dak you did that yourself? is that the after shot? If you did that yourself did you just dremel that ot? I know lots of questions.
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SterlingCTdak
Dodge Dakota
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8/20/2005
17:03:58
| RE: throtttle bodies
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Was just on dodgetruckworld.com and got another great idea for porting your TB. Try using a 3" flapper wheel.
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N56629
Dodge Dakota
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8/20/2005
22:50:13
| RE: throtttle bodies
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3" flapper wheel? That sounds like a great idea.
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4.7onNO2
Dodge Dakota
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8/22/2005
20:23:41
| RE: throtttle bodies
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I did the cams and the tb porting seperatly.
I Knowticed a big difference after the cams then two weeks later I ported and felt a reasonable difference. But put together it really woke my truck up for only $250. I just used a die grinder and it tore that metal out REAL QUICK. Aluminum is so easy to work with. Total time was about an hour. even had time to get in there with a polishing wheel. I honestly dont think its worth buying a TB unless you have alot more mods planned. its not really worth 3 or 4 hundred dollars to get maybe 3-5 more hp than a ported one.
P.S. Dremels suck. payup the first time for a diegrinder and you will have it forever.
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GraphiteDak
GenIII
8/23/2005
01:09:10
| RE: throtttle bodies
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ecdak, I forgot to check this thread again.
I used an air rotary. Or maybe what 4.7onNO2 is calling a die grinder.
I used a course bit and took out that "torque step" first which was easy to see by eye. Once it was gone I used some more fine sanding papers on my wheel and polished it up a bit.
I noticed NO CHANGE in idle. My bro in law just ported his 5.2 and his idle went up. OOPS!
More pics...
There's a pic of my assorted bits I used.
I've got an idea to build a home brew intake one of these days. Dual runners, with a "secondary" Throttle Body :) May really open up some high RPM power and retain low end grunt. May even increase low end if I do it right. Thinking of using a micro controller to open secondary to the SHORT RUNNERS at a certain RPM. Kind of like how Nissan now does with their Maxima, etc but they use some sort of valve in the intake and a single TB. But you get the idea. Making the best of both worlds.
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4.7onN02
Dodge Dakota
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8/23/2005
17:31:39
| RE: throtttle bodies
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Interesting idea with the 2nd TB. I was thing of trying something similar with some electic exhaust cutouts. You know open the exhaust before the cat at 3500-4000 rpm to gain hp and not loose the low end. Put together with the same rpm window could possably give you some crazy top end power.
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GraphiteDak
GenIII
8/23/2005
22:27:00
| RE: throtttle bodies
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Hate to bring up NISSAN again. But in the Maxima they have a flapper valve in their muffler that supposedly opens when backpressure exceeds a certain amount.
Other than that, I'd rather not have a Nissan. They SUCK to work on compared to these.
I'm wondering how I should go about fabricating an intake. Wheather I should mod an old non HO one I could buy cheap. Or try and build one from scratch.
Using STEEL I know I could mock one up. But not so sure if it would retain the seal, expansion/contraction etc.
I could make an attempt with Aluminum. But I haven't done much with that, and how would mine turn out looking??? Questionable :p
Those who have changed their 4.7 intake, what did the gasket look like? Are the o-rings held in place by one long gasket?
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4.7onNO2
Dodge Dakota
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8/23/2005
23:50:22
| RE: throtttle bodies
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A flapper valve huh. It would have to be pretty durable
to work for a long time but it sounds like a good idea.
I dont know about fabricating your own intake. Sounds
like way to much work for me. When you fab your own
intake usualy its because your trying to move your
power band up (shorter runners) or down (longer
runners). I wouldn't want to move ours too much either
way. Just make it wider and i dont think an intake is
gonna do that for ya. Gotta love a nice wide powerband
though, good for towing or racing.
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Rob C
Dodge Dakota
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8/24/2005
00:44:38
|  RE: throtttle bodies
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What gasket? There's just the "O-rings" against the machined surface of the heads. Here's are pics of the different intakes ('02 HO & '03-'04): http://www.wjjeeps.com/manifold.htm
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