Throttle Body Mod on 2002 sohc 4.0

[trucku]

HOW TO: Throttle Body Mod on 2002 sohc 4.0

I have decide to see if I could modify the throttle body for some better airflow. I figure any gain in mpg is a good gain.

I am getting just barely 19mpg on the highway with this truck. I suppose its not so bad since she is a 4x4 and that leads to a huge factor in mpg.

I decided to mod the throttle body, because few weeks ago I had the intake tube off and noticed something interesting, a bunch of vanes. I guess they have them there to smooth out the airflow IMO they just take up space. The leading edge is also flat and is 1mm wide. That is turbulence right there.I measured them and it there are 11 lengths 1mm wide and 12mm long. that is 132mm square of surface area taken up in the throttle body and not including the little tiny vanes on the top half.

I decided not to try to mod the shaft at this point. If i mess this up I will would be in a dilemma , so I will keep it simple and see what happens.

I have a cheapo little saw I bought for 2 dollars form the 99 cent and up store, so I used that to for my cutting. I don't have a dremel tool.

I did not have to cut completely through each little plastic vane. I just scored them well and straight as I can and pushed on them with my thumb. If they didn't break I just went at it a little more. I was able to break them right off right on the cut line.

I secured the throttle open with a zip tie.

After I cut them all both from the bottom and top of the inside of the throttle body, I used some small files to smooth everything out.
IT took a long time, because I took my time. I didn't want to get crazy and score up the inside of the throttle body where the plate sits when at idle. I don't want any air bypassing around and causing issues.

Here it is done. I used some compound to polish it the best I can inside. Again this was all manual labor since I don't have a dremel tool. Notice I also cut the 2 screw ends sticking out past the shaft.

I am happy with the outcome. Again I did not want to get risky and try to cut the shaft and shorten the screws. Maybe when my extended warranty runs out. I don't want to void anything.

use your file carefully and don't gouge the inside of your throttle body.

I will post my mpg gains if any from a highway run to Long Island this weekend.

 

[E.B. Cornburner]

Those vanes are in there to eliminate partial-throttle "whistle" or "woosh" sounds. I remember reading a TSB about that some time ago when I discovered the same thing on a ~'97 Explorer.

I really don't think eliminating them will accomplish a whole lot. But, I don't think it'll hurt anything either.

 

[trucku]

I figure any mm gain is a good gain. Yeah I figure it wouldn't hurt.
this friggin truck whistles and burps all kinds of digestive sounds too...lol

It interesting to cure the sound issue they have vanes installed and lessened the air flow through that throttle body. I am going to cut the shaft sometime soon. It is pretty substantial in there. I can't find my stickies with my measurements if the inside area minus all the mechanical parts. I know the airflow is only as efficient as the smallest space, so I cannot do much with this throttle body.But I know millimeters count so we'll see.

Thanks for the "fyi". I thought it was just weird to take up space with the vanes.
I don't have the budget to throw at mods at my truck, so I will try freebies first. I have to say though my scanguage is showing 1mpg on the same route I drove the other day. Probably just my mental mod and not much more.

 

[aldive]

I really don't think eliminating them will accomplish a whole lot. But, I don't think it'll hurt anything either.

It will greatly improve the air flow volume.

 

[E.B. Cornburner]

I'm not disagreeing that it may improve the overall airflow of the throttle body, but if the engine's airflow demands don't exceed what the TB was flowing originally, it's a moot point.

By my calculations, this engine has a maximum airflow of 425 CFM @ 6000 RPM, assuming 100% VE, which we both know isn't possible on a naturally aspirated engine.

Now, if the stock TB flowed say ~450 CFM, even with the vanes, by improving its airflow even more will accomplish nothing...The engine isn't able to use any additonal flow, so no gain will occur. Sometimes, even the opposite is true. You put too high of a flowing TB on the engine and lose power because the air velocity is reduced.

Same goes with air intake systems. By adding a high-flow filter/intake, you may not see any gain if the stock airbox already has sufficient airflow for the engine's demands.

 

[trucku]

I guess then if your going to put a higher flow TB then to maintain the air velocity it would be best to put in a intake that would force air into the system at speed. I don't know how much of a pressurizing affect it would have. The Airbox Big drain holes.

It seems from what i read here that the larger TB are making a difference. So does that mean that the stock TB does not meet the demand of the engine?

I think the best gains would be at speed when the throttle is in a mid position and turbulence or some sort of back pressure would result form the flat face of the vanes and orientation.

 

[manaen]

post some pre/post MPG numbers when have time to test it.

 

[trucku]

will do.

NY traffic on highway is almost as bad as street. gonna try this weekend in the evening. I will be using my scanguage. I have 4 fills on it now and its pretty much spot on.

 

[E.B. Cornburner]

If bigger throttle bodies are making HP, that means the OEM one wasn't flowing as well as the engine was demanding.

Like I mentioned, some TBs are just fine as-is, other's aren't. The Dodge 4.7 is an example of one that's best left alone. Port & Polish one and they'll have all sorts of driveability issues including cruise control problems, torque convertor clutch "hunting" etc. Not to mention, they don't make any more power than a stock one.

 

[trucku]

Thanks for the information you've been giving me. I totally agree with what your saying. It would definitely account for a particular mod working for one vehicle and not another.

I was definitely worried about adverse affects.

 

[E.B. Cornburner]

If those vanes cause a large enough restriction in the airflow at partial throttle, by removing them, you'll definitely notice a much crisper tip-in response.

GM did something similar on the Vortec 4.3...They added a big aluminum "wing" to the backside of the throttle plate which blocked off roughly half of the bore from tip-in to ~1/3 throttle, and was progressively shaped so that it would give a smooth transition from closed to open throttle. Remove it, and weld the little rivet holes shut, and it wakes them up big time, even at WOT. Only thing is it's very touchy on tip-in after removing it. I'm sure that's the main reason for it in the first place...To give a smoother tip-in response while driving with very light throttle openings.

Maybe there's more to it than just reducing intake noises? It could have some of the same effect as the GM design, though much simpler. I know Dodge throttle bodies are a progressive bore design too, and for the same reasons.

 

[aspitaletto]

seems like a decent mod actually. i wonder if my TB has these 'veins' because at 30-50% throttle, i hear all sorts of whistleing under the hood. ill have to check...

 

[trucku]

Today showed 19.8 (ac on) on highway. I don't know if that is a viable reading. Because on the way back from Long Island I just heavy footed it and was getting 16 max on the Long Island Expressway.


Again I have to make a few more runs, but this rig has never seen 19.8 mpg ever. I drove to Florida few years back and max I got was 18 (ac on) with cruise control nonstop full tank to empty.

I will say it feels peppier from a stop. She comes on right away when I step on it withing 0-30mph. That is definitely felt IMO. IMO its feels like it would when the ac is off.

I can definitely hear the air whooshing when the hood is up and stepping on the gas pedal. Before the mod it was much more quieter.

When I messing with this throttle body I took a look into the intake manifold and it had a nice coating of sticky buildup all around. I will take it that is also sitting into the head and probably around the valves. I am going to pull the throttle body off and saturate that buildup with some sea foam. I will just use a empty windex bottle to spray it around the inside on the misting setting. After that is done I will spray into the throttle body while the truck is running with intake hose off.
Maybe I shouldn't of, but I cleaned the throttle body with warm water and a soapy tootbrush, then blasted it free of water with a can of compressed CO2 that I use for my pc. Worked pretty good I think.

 

[aldive]

With my Ford Racing 4.6 Mustang TB ( http://www.explorerforum.com/forums/showthread.php?t=139454&highlight=mustang ), I definitely saw mileage increase as well as power. Further, when this TB was ported and shafted ( http://www.explorerforum.com/forums/showthread.php?t=172480 ), the mileage once again went up as well as perceived power.

There is definitely room for improvement in the stock TB and TB modification is definitely a worthy mod.

 

[trucku]

Yeah read your thread again,just before I mod the throttle body.
It inspired me to go ahead with it.

I will try to exploit as much mileage out of this truck. I don't expect an overly impressive gain since its this is a 4x4 and that being my greatest handicap.

Slowly but surely is the way to go. Oh yeah its my families only vehicle so I can't break it...

 

[aldive]

Slowly but surely is the way to go. Oh yeah its my families only vehicle so I can't break it...

Have you considered UD crank pulley?

 

[trucku]

Yes I have. I think that coupled with the removal of the clutch fan would be a great merge of 2 upgrades.

I have been weighing out what my current very limited budget of $200 can get me as next upgrade.

I have yet to install my electric fan and controller, which should make a measurable difference.

 

[aldive]

Both of those mods are indeed prudent ones for your intended gas mileage goal.

If I were you, I would go with the UD Pulley mod first. You will get the most bang for the buck there.

Good luck and keep us informed.

 

[trucku]

Thanks for the "experienced advice"

I think that will be my next purchase.

I will keep you guys updated.

 

[E.B. Cornburner]

I'm reluctant to mess with mine just because of the drive-by-wire system. If anything, maybe I'd find a TB in the salvage yard to hack up, and if it doesn't work, put the old one back on. On the Dodge Magnum 5.2/5.9 engines, I'd do a complete P&P and shaft work to them, and they did wake up the engine considerably, and improved MPG. Never messed with a Ford yet though.


Edit:

This is great news! The '04+ with the drive-by-wire throttle body doesn't have these little "teeth" in the TB itself...They're in a little plastic gasket/spacer between the TB and the intake plenum! Took mine apart, spent about 10 minutes removing the "teeth" from this spacer with a die grinder, and reassembled it. There's now a pronounced "swoosh" when I tip the throttle in. Whether or not it improved anything remains to be seen, but it was a fun little mod at the very least. I probably wouldn't have messed with it if it were part of the TB, but since this piece is seperate, if I did eff something up, it's easily replaced with a new one.