TB Mod
#1
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Most posts by FC owners have in either their profile or sig. that they have done a throttle body modification. I read up on the "How To" of preforming this mod. but I really want to know how difficult it really is (or is it?) and how much time this will take to preform. Also is there a significant increase in power? Info is much appreciated. Thanks.
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#2
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Originally Posted by BlackRocket
Most posts by FC owners have in either their profile or sig. that they have done a throttle body modification. I read up on the "How To" of preforming this mod. but I really want to know how difficult it really is (or is it?) and how much time this will take to preform. Also is there a significant increase in power? Info is much appreciated. Thanks. ![Smilie](https://www.rx7club.com/images/smilies/smile.gif)
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#3
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i felt a big diff... but then i did it at the same time i threw on a cai heh so it wasnt the TB mod the but dyno was feeling... however why not every little bit helps especially if you mod the car up alot later on down the road. its not difficult but if you port be careful you dont port a hole in the side of the TB, its common sense really, if your too close to the edge STOP... good luck if you do it... check my sig for a picture of mine
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#5
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be aware if you do the full tb mod you might run into cold idle/warm idle problems. i recomend you just take out the front two throttle plates and maybe port it. i wouldnt take off the thermowax and the rest of the stuff again, it caused problems for me. not everyone though, but just my opnion.
#6
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Taking out the thermowax is not part of the TB mod IMO. It's . . . uh . . . weight savings? :-p
I honestly cannot see the benifit to removing the thermowax, unless you LIKE a bad cold idle.
I honestly cannot see the benifit to removing the thermowax, unless you LIKE a bad cold idle.
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Originally Posted by Tofuball
Taking out the thermowax is not part of the TB mod IMO. It's . . . uh . . . weight savings? :-p
I honestly cannot see the benifit to removing the thermowax, unless you LIKE a bad cold idle.
I honestly cannot see the benifit to removing the thermowax, unless you LIKE a bad cold idle.
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#9
i am legendary
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For turbo it is a very helpful thing to do, for N/A it's worthless, honestly, unless you're porting your TB at the same time. The weight savings on the TB mod is 2.6 pounds in total on an N/A, for anyone curious
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There is one on www.fc3spro.com but the site is down currently.
#13
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I wouldn't call the mod worthless on an NA. I could really feel the extra power after I did it. My power now falls off at 7500RPM instead of 7000. I also like the crisper upshifts I get with the throttle damper removed. I didn't remove the thermowax. It wouldn't have saved much weight, doesn't flow coolant through the TB and leaves me with a good idle.
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#17
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I don't get flames because I still have a cat and baffled mufflers, but I can hear a pretty good pop when I close the throttle to shift from redline. A friend of mine told me I'm hurting my sideseals by switching to that much vacuum that quickly, but I just don't see how it could hurt anything. (Besides, now I can shift mad quick yo...) ![Wink](https://www.rx7club.com/images/smilies/wink.gif)
BTW, it's really easy to do the mod. Just start with a spare TB so you don't feel rushed.
Take off everything from the outside that isn't the main set of throttle plates. Save the cold start thermowax, TPS, throttle cable support and anything connected to the OMP.
Take out the second set of secondary throttle butterflies and then their throttle shaft. Don't worry about them, you won't want to put them back in.
Smooth, port and polish the inside of the TB for more gains. I believe in leaving as much of the center divider in place as possible so the air is moving a little more smoothly when it hits the throttle plates and radiusing the upstream edge for minimal turbulence.
You can check the alignment of the butterflies at full throttle. I ground down the stop on my primaries for a bit more opening. Replacing the (most likely) worn bushings on the secondary butterfly linkage should help if it's not opening fully.
Thinning and smoothing the throttle shafts should help some, as well as replacing the buttonhead screws with countersink screws. I seated my screws and then finished smoothing the shafts so the screw heads had the same shape as the shafts.
Radiusing and blending the trailing edges of the throttle butterflies might help power a bit, and since it allows more airflow at a lesser throttle position, gives the motor the illusion of having more bottom-end torque than it really has.![Smilie](https://www.rx7club.com/images/smilies/smile.gif)
If you do any work on the throttle shafts or butterflies, it's a lot easier with them out. Just pay attention to the assembly order when you take it apart and be gentle with the shaft seals.
Assembly is the reverse of removal. Be sure to clean everything very thoroughly! It doesn't take a lot of metal shavings to severely shorten your motor's life...
Also, be sure to adjust your TPS, idle bypass and mixture trim when you get everything together.
Here are a couple pics of the work I did on mine. I welcome comments.
![Wink](https://www.rx7club.com/images/smilies/wink.gif)
BTW, it's really easy to do the mod. Just start with a spare TB so you don't feel rushed.
Take off everything from the outside that isn't the main set of throttle plates. Save the cold start thermowax, TPS, throttle cable support and anything connected to the OMP.
Take out the second set of secondary throttle butterflies and then their throttle shaft. Don't worry about them, you won't want to put them back in.
Smooth, port and polish the inside of the TB for more gains. I believe in leaving as much of the center divider in place as possible so the air is moving a little more smoothly when it hits the throttle plates and radiusing the upstream edge for minimal turbulence.
You can check the alignment of the butterflies at full throttle. I ground down the stop on my primaries for a bit more opening. Replacing the (most likely) worn bushings on the secondary butterfly linkage should help if it's not opening fully.
Thinning and smoothing the throttle shafts should help some, as well as replacing the buttonhead screws with countersink screws. I seated my screws and then finished smoothing the shafts so the screw heads had the same shape as the shafts.
Radiusing and blending the trailing edges of the throttle butterflies might help power a bit, and since it allows more airflow at a lesser throttle position, gives the motor the illusion of having more bottom-end torque than it really has.
![Smilie](https://www.rx7club.com/images/smilies/smile.gif)
If you do any work on the throttle shafts or butterflies, it's a lot easier with them out. Just pay attention to the assembly order when you take it apart and be gentle with the shaft seals.
Assembly is the reverse of removal. Be sure to clean everything very thoroughly! It doesn't take a lot of metal shavings to severely shorten your motor's life...
Also, be sure to adjust your TPS, idle bypass and mixture trim when you get everything together.
Here are a couple pics of the work I did on mine. I welcome comments.
Last edited by ScrapFC; 11-02-04 at 02:30 AM.
#19
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this is the link for the TB i found it to be pretty helpful http://www.fc3spro.com/TECH/HOWTO/TBM/tbm.html
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Originally Posted by 2ndGenV8RX-7
is a baffled muffler like the cheap o looking round ones that are almost 2 ft long?
#21
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Originally Posted by BlackRocket
this is the link for the TB i found it to be pretty helpful http://www.fc3spro.com/TECH/HOWTO/TBM/tbm.html
I have to wonder how much of my gain was in removing the extra shaft and butterflies and how much was due to othe airflow cleanup...
#23
i am legendary
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That's the consensus with a lot of people, however I have had different results. For some reason it seems like I'm one of the very few that has a perfect idle with a full TB mod, go figure ![Smilie](https://www.rx7club.com/images/smilies/smile.gif)
Edit - even when it is freezing out and the engine is cold.
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Edit - even when it is freezing out and the engine is cold.
Last edited by ddub; 11-02-04 at 10:03 PM.
#25
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Originally Posted by Kenteth
You live in new york? DO NOT REMOVE THE THERMALWAX. You will be very upset with yourself if you do.