Tips On Modifying Your Throttle Body

[N56629]

I've seen some horrible Dremel jobs and I'm sure they have scared off some from doing it themselves. Awhile back I acquired one of these hacked TB's with a bunch of other parts. Sometime afterwards I looked at it and thought how could it have been done better.

The best tool that I found to open up the bore is a two inch flapper wheel. Shaping the radius was done with a combination of a mandrel mounted abrasive and a three inch shaped flapper wheel. The two inch flapper is the perfect diameter for opening the bores and eliminating the step.

Start by removing the throttle shaft. You can achieve a taper by working tool up and down taking a few extra strokes near the top. Be careful and do not allow the tool to go below the holes for the throttle shaft.

The radius is somewhat more difficult but I got good results by being creative. I made a simple rotary table of sorts by nailing a short 2x4 to a bench or you can nail it just about anything, kitchen table, patio post, etc. :joke: :jester:

This is where a friend would come in handy but I managed to do it by myself. Fasten the tb to the 2x4 with wood screws with the bore centered over the pivot point (nail.) Take the mandrel mounted abrasive and roughly shape the radius on both bores. After you have done that take the three inch flapper wheel and use a file or grinding wheel with the flapper wheel turning to shape the desired radius on the bottom. Then use the wheel to true up the radius.

The flapper wheels and other abrasives are available in various grits. Since most of the metal was already removed on my project I only used 120 grit to rough and finish the bore. The radius was done with an 80 grit but it took a lot of work to polish out the scratches.

Now I don't usually polish the TB when I machine them because I have seen no measurable difference. Let me just say that there is evidence out there that suggests texture surfaces can actually increase laminar flow. The important thing is have a smooth consistant profile. An irregular surface, even if polished to mirror finish will not flow as well as a smooth uniform 80 grit finish.

On this particular project the surface, the remaining two ears and boss for the airhat screw were ground off using a two inch disk in a right-angle grinder. Just before the final polish the entire TB was bead blasted. If you decide to grind off the boss for the airhat screw you will have to drill and tap it deeper and make an S-bolt. It's a little extra work and achieve little or nothing but it makes for a neater job.

Start- Hacked TB

http://img.photobucket.com/albums/v311/N56629/HackedTB.jpg

The Tools-

http://img.photobucket.com/albums/v311/N56629/Throttle%20Bodies/P6092612.jpg

The Process -

http://img.photobucket.com/albums/v311/N56629/Throttle%20Bodies/P6092604.jpg

The Finished Product -

http://img.photobucket.com/albums/v311/N56629/Throttle%20Bodies/P7022637.jpg

[Jason]

That looks awsome :clap2: . You want to do one for me :biggthump ???

[realdeal7369]

that 2 inch flapper sanding wheels does a nice job for the tb bore holes on the intake too. did mine on my dak a little while ago.. :banana2:

[N56629]

that 2 inch flapper sanding wheels does a nice job for the tb bore holes on the intake too. did mine on my dak a little while ago.. :banana2:

That's the only one I'll ever do by hand again. Way too much work to get it that good. I just had to see if I could do it. I knew there had to be a better way than using a dremel type tool and router type tools.

[DakotaQC2000]

What is the completed diameter of the ports? (i.e. 50mm, 52mm). I would imagine the throttle plates no longer match up to the port size as well - is this a problem? Also, why not just taper the airhats?

Thanks for the info,
2000DakotaQC

[Mopar4Life]

Wow, the finished product looks A+++++++. :biggthump Great work man! I wanna try this myself.

[xtreme6669]

What is the completed diameter of the ports? (i.e. 50mm, 52mm). I would imagine the throttle plates no longer match up to the port size as well - is this a problem? Also, why not just taper the airhats?

Thanks for the info,
2000DakotaQC

the plates should fit just fine seeing as that he made a note not to go past that point in the bore

[InTeNsE98RT]

All that does is turn it into a true 50mm by removing the step inside the bore. Doing so will give it an increase in airflow which equals power.

Here is the first TB I bored out. Too big for my V6 but it makes a nice paper weight :jester:

http://i3.photobucket.com/albums/y97/blue2000sport/bigblue.jpg

[Mopar Mike]

Very impressive! I always used a port & polish kit designed for doing heads with my die grinder, but I'm going to have to look into those flapper sanding wheels!

What size do you think I'd need to do a 4.7L throttle body?

There shouldn't need to be much of a radius shaped into the inlet on a 4.7 TB, but I'd definitely like to play around with a couple.

This looks like the beginning of a fun project!

One last thing...How fast do those flapper sanders remove material, and how long do they last? Will one do a complete TB, or should I get a spare?

[InTeNsE98RT]

I would get 2 of them cause they seem to wear down fast or at least they did for me

[Mopar Mike]

In the immortal words of Bo and Luke Duke...YEEEE HAAAAAAAAA!!!!!!!

Just came back from the shop where I ported my first 4.7 throttle body. Wow! What a difference!

I did the flapper sanding wheel trick with a drill, and finished it up with some fine buffing compound on a cloth buffing wheel that I had laying around that was the perfect size to fit the bore. I proabably wouldn't have gone so radical had I not found this sitting there doing nothing. Finished up with a little hand polish with some Nevr-Dull, and put it back together.

I also removed the little plastic "dimple" from the top of the intake manifold where the TB mates up to it. I just scored both sides with a razor knife, and twisted it off with a needle-nose pliers. Not sure if it'll do anything or not, but it looked like it was in the way of smooth airflow, so off it came.

Took it out for its initial road test (after finishing up my temper tantrum when I dropped one of the air silencer screws way down between the plenum and the head) and at first it seemed unimpressive. I couldn't really tell any difference in throttle response while cruising, though I did notice it being a little "crisper" when putting around the parking lot at the shop. Took it out on a back country road and planted my right foot, and it bogged and sagged miserably before it started to come alive. I guess I should have disconnected the battery so the PCM could re-learn. Once its initial fit was over, it started to pull like a freight train! I never realized how smooth a 4600# vehicle could be at 110 MPH! All the way home I couldn't stop kicking it down to 2nd (or is it 3rd, or 2nd Alt.?) at 60 MPH just to let it wind out to ~85 MPH and upshift, only to slow down, cruise a little, then do it again!

The more I drove it, the better it got. I've had the "air bog" before when I did TBs on 5.2s so it didn't make me too nervous. It just takes some time to learn the new amount of air that it's inhaling.

I'm certainly not going to get any MPG on this tank!

[realdeal7369]

In the immortal words of Bo and Luke Duke...YEEEE HAAAAAAAAA!!!!!!!

Just came back from the shop where I ported my first 4.7 throttle body. Wow! What a difference!
I did the flapper sanding wheel trick with a drill, and finished it up with some fine buffing compound on a cloth buffing wheel that I had laying around that was the perfect size to fit the bore. I proabably wouldn't have gone so radical had I not found this sitting there doing nothing. Finished up with a little hand polish with some Nevr-Dull, and put it back together.
I also removed the little plastic "dimple" from the top of the intake manifold where the TB mates up to it. I just scored both sides with a razor knife, and twisted it off with a needle-nose pliers. Not sure if it'll do anything or not, but it looked like it was in the way of smooth airflow, so off it came.

Took it out for its initial road test (after finishing up my temper tantrum when I dropped one of the air silencer screws way down between the plenum and the head) and at first it seemed unimpressive. I couldn't really tell any difference in throttle response while cruising, though I did notice it being a little "crisper" when putting around the parking lot at the shop. Took it out on a back country road and planted my right foot, and it bogged and sagged miserably before it started to come alive. I guess I should have disconnected the battery so the PCM could re-learn. Once its initial fit was over, it started to pull like a freight train! I never realized how smooth a 4600# vehicle could be at 110 MPH! All the way home I couldn't stop kicking it down to 2nd (or is it 3rd, or 2nd Alt.?) at 60 MPH just to let it wind out to ~85 MPH and upshift, only to slow down, cruise a little, then do it again!

The more I drove it, the better it got. I've had the "air bog" before when I did TBs on 5.2s so it didn't make me too nervous. It just takes some time to learn the new amount of air that it's inhaling.
I'm certainly not going to get any MPG on this tank!

deffinately reset the computer. once things are disconnected, the computer throws a fit. also...

:needpix:

[realdeal7369]

All that does is turn it into a true 50mm by removing the step inside the bore. Doing so will give it an increase in airflow which equals power.

Here is the first TB I bored out. Too big for my V6 but it makes a nice paper weight :jester:

http://i3.photobucket.com/albums/y97/blue2000sport/bigblue.jpg

nice damn tb man!... sweet :biggthump

[Mopar Mike]

As much as I like my ported TB, I'm going back to a stock one. The performance gains were impressive, but for the basic commuting that I do, it's a little too touchy. I see now why they have that ridge in the upper bore...It allows the throttle to be more "progressive" at light openings, and by removing this, it now becomes more of a "hair trigger" feeling when just driving lightly around town.

I'll probably keep it around just for the sake of saying I did it, or maybe put it on my dad's Dakota sometime and scare the crap out of him the first time he floors it! :drive: :biggthump

[bakerlaw67]

In the immortal words of Bo and Luke Duke...YEEEE HAAAAAAAAA!!!!!!!

Just came back from the shop where I ported my first 4.7 throttle body. Wow! What a difference!
...
All the way home I couldn't stop kicking it down to 2nd (or is it 3rd, or 2nd Alt.?) at 60 MPH just to let it wind out to ~85 MPH and upshift, only to slow down, cruise a little, then do it again!

There has to be a name for this affliction. I have the same "problem". It pulls SOOO strong from 60-90 that it feels twice as strong as it actually is. Really fun stuff! It pulls really strong at lower speeds with the OD off.

And I haven't noticed any tip-in. The thottle is pretty controllable. This is not to say that I don't find myself generally running at either idle or WOT, but it is through no fault of the TB ;)

[Katalyst]

just wondering if this would work good on a 3.9 V6. Don't want to start ripping things apart and doing modifications then ending up not being able to use my truck untill I order in a new TB.

Thanks
Chris

[N56629]

just wondering if this would work good on a 3.9 V6. Don't want to start ripping things apart and doing modifications then ending up not being able to use my truck untill I order in a new TB.

Thanks
Chris

Works the same way. This wasn't written as encouragement to do it but advice on how to do it better. If you don't have faith in your ability to do the job then it is best not to start it.

[flyboy01]

Off topic.

N56629 - I like you OTHER Dakota! I have flown a bunch of Warriors and Arrows, that is a nice one you have.

[N56629]

Thanks, it just had a new paint job. I would like to get rid of the Hersey bar wing tips but don't want to give up the fuel. 82 gals. lets me go a long ways.

[Katalyst]

Works the same way. This wasn't written as encouragement to do it but advice on how to do it better. If you don't have faith in your ability to do the job then it is best not to start it.

Understood. I do all the modifications to my truck so everything I do is a risk.....plus the only way to really learn. Ordering in a new TB to try it on first so we'll see what happens. Thanks for the info.

Chris

[AmberFireDaK]

Understood. I do all the modifications to my truck so everything I do is a risk.....plus the only way to really learn. Ordering in a new TB to try it on first so we'll see what happens. Thanks for the info.

Chris

I have one off my 2000 360............PM me if your interested.

[Katalyst]

I have one off my 2000 360............PM me if your interested.

:banana2: Definately interested. Just sent you a PM.

[turbographx]

Just wanted to throw in my 2 cents worth on this topic.
The flapper style sanding wheels is a GREAT way to port and polish any round opening. We have been using them in the import scene for many many years for this purpose. I even use the small ones to help get the corners in the intake and head ports.
If you are wanting to try this, I'd sujest getting a used TB and porting it. Then swap them out once you are done. Keeping the stock one on the "D" while making the other one means no down time and no rush to get the job done. As with ANY porting job, patience is key! This is NOT something you want to race to finish as a bad porting job can COST you performance rather than gain performance. :wave:
K Evans

[Moparman]

I cannot find a stupid 2" flapper wheel anywhere up here in Canada. I have had to use wire wheels and 320 grit sand paper :(

[InTeNsE98RT]

I cannot find a stupid 2" flapper wheel anywhere up here in Canada. I have had to use wire wheels and 320 grit sand paper :(I dont know if you have a NAPA store up there but thats where I get mine.

[N56629]

Check with any welding or machine shop and ask them where they buy thier supplies.

Here's just one of the places we buy from -MSC (http://www1.mscdirect.com/cgi/nnsrhm?KNC-T7L391316886)

There are many more just like them. 3M products are among the best but other brands work just as well for this application. Do a search for suppliers of these products.

[Moparman]

thanks alot!~ :biggthump

[SteedstER]

Here's one of the two I bored out over the holidays. 50mm and thinned the shafts. Got button heads to replace the stock mounting bolts.

[Moparman]

this is what I have so far:
http://www.putfile.com/pic.php?img=4519381
throttle body bored out to 51mm :biggthump (too big for a 3.9?)

http://www.putfile.com/pic.php?img=4519380
Most of the top crap shaved off (not fun with only hand tools)

http://www.putfile.com/pic.php?img=4519384
And in this one you can see what the wire brush did, also shown in the 2nd pic (this is after atleast 2hrs of sanding)

what can I do? :cussing:

[Bacon88]

I'm confused, what about the room between the body's wall and the throttle flap? Does this affect anything? Someone help me out here.

[AmberFireDaK]

I'm confused, what about the room between the body's wall and the throttle flap? Does this affect anything? Someone help me out here.

yes it does affect it...... if you bore the the TB you have to make new butterfly valves. Or your idle will be really high lol.....That's why I only shaved mine :onethumb:

[realdeal7369]

where do you get them from then?

[AmberFireDaK]

this is what I have so far:
http://www.putfile.com/pic.php?img=4519381
throttle body bored out to 51mm :biggthump (too big for a 3.9?)

http://www.putfile.com/pic.php?img=4519380
Most of the top crap shaved off (not fun with only hand tools)

http://www.putfile.com/pic.php?img=4519384
And in this one you can see what the wire brush did, also shown in the 2nd pic (this is after atleast 2hrs of sanding)

what can I do? :cussing:

Get a light grit sand paper (wet sand paper works best) and a piece of dowel that's the same diameter as the bore on your TB. Wrap the sand paper around the dowel, and sand away

If you can't find a piece of dowel you can do it by hand.....just be careful not to stay in the same place too long.....useing a finer grit sand paper will help make sure you keep the bore uniform.........but it will obviously take longer to do

[N56629]

I have been known to fix some pretty screwed up tb's.

I know it seems to go against some of the conventional wisdom around here but it's pretty hard to make a throttle body too big for the v6. The intake manifold and not the tb is the limiting factor.

Yes, if you make the bore larger than the throttle plate you have a problem unless you can make new ones. As someone pointed out, it will not idle if the gap is too big.

FWIW, I found that trimming the top is a waste of time. It looks good but doesn't do a thing for air flow.

[Bacon88]

How do you make the the new flaps? Or do you buy them?

[Mopar4Life]

How do you make the the new flaps? Or do you buy them?

Reviving an old thread...I'm interested too in how to make perfect throttle plates (blades)

[moore_716]

I'm sure he stamped them out. I didn't realize we had the mandrels and stuff at my old job to do this till right before I quit. Basically I was gonna use a die set at the diameter I wanted and then use a hydraulic press to pop them out.

[03'Dakota]

so you would have to make the new flaps? that sucks :(

[AmberFireDaK]

so you would have to make the new flaps? that sucks :(

You only have to make new valves if you bore out the TB...you can shave off the fins and radius the edges, you can even sand down the step in the bore without having to make new valves

[IowaSQ]

the blades aren't perfect circles.

[Mopar4Life]

Where can I get a flapper wheel? I can't find them anywhere anymore.

[IowaSQ]

lowe's

[threesixoh]

I'm more interested in knowing where to get new blades, and how to remove/install them into the throttle body

[1LOUDRT]

just buy a small piece of aluminum from lowes and make your own tb blades- doesn't get any easier or cheaper than that

[threesixoh]

just buy a small piece of aluminum from lowes and make your own tb blades- doesn't get any easier or cheaper than that

I dont have the tools or know-how to fabricate something that requires as tight of a tolerance as throttle body blades, I was hoping for a place where I could source them.

[N56629]

Reviving an old thread...I'm interested too in how to make perfect throttle plates (blades)

I didn't realize someone resurrected this thread a year later. Oh well, maybe you can use an answer that is a year late. For all practical purposes they are round and made in a lathe. The sides are slightly flat and can be finish fitted with a file.

A slightly more difficult problem is putting the screw holes in the right place. The holes are offset. Just take the hole dimensions off the old plates.

If you make one like the above example you shouldn't have to make new plates.

[wingerak92]

So, if one were to port a throttle body in a 4.7L, would that be like taking it from the stock 68.5mm to 70mm? if so, any tips?