[OKIERX-7]

I thought some of you might be interested in this. You remove your secondary intake butterfly plates, this provides better flow in the high rpm range. This works for both turbo 2s and NAs of any year. Anyways here's the link

TB MOD

[1Revvin7]

I did it, i didn't notice any drop in low end power, but a little gain past 4000-5000rpms.  But the engine is alot more responsive and quicker revs.  It does clean everything up and gets rid of the coolant that flows through it. The coolant heats up your TB, air going through the tb gets heated, heat= less power. The secondary thottles plates also cause a restriction even when completely open, getting rid of them gets rid of this restriction. Its a little rougher on the warm up if u live in cold areas though.

[mazdaspeed7]

Im running my car with a modded and ported TB. Also, I have no BAC, or any other emissions crap on it. No a/c or p/s either. When I did the tB mod, I removed the thermowax and fast idle cam, and everything unnecessary off the TB. My car starts right up, idles fine at 1000 rpm when cold, never stalls, and drives great. I dont miss any of the stuff I took off.

[pengaru]

i usually would let it warm up long enough for the thermostat to open, you can usually feel it when it opens up esp. if it's cold out and the temp gauge will start moving more when it opens up.

it's worth it just for how much cleaner it lets you make the engine bay, if you elminate the double throttle and the thermowax, you can eliminate the coolant hose and the throttle body gets alot cleaner.

[1Revvin7]

Another useful thread

[FCmaniac]

I started and stopped part way through.... something else I need to finish.

Has anyone done the TB mod with JB weld and how has it held up? Please give mileage, etc. Some people told me to stay away from the JB weld.

[1Revvin7]

I used on my old N/A. Worked fine, I only used it for like a couple hundred miles though. I'm tapping them on my T2 though, no more ghetto shit for me.

[ILUVMY88CABRIO]

I did it to my AE, and my boost didn't change at all. You do gain a decent amount of top end power. My buddy with a S5 TII couldn't keep up with me from 80+ mph. We both had only cone filters, and he was running more boost than me.

[mac_dad6]

i did the mod on my 87 t2 and i love it. the car hesistates a little if you are trying to go slow but it's a small price to pay for the adde throttle response. it took me about an hour and i used jb weld to seal the holes. it was a very worthwhile mod.

[FCmaniac]

I just finished the mod on a spare from the FC3S-pro instructions. Did you guys who have done it go through the TPS set up when you put the TB back in? I was also wanting to polish the inside real good to smooth it out. I was wondering if I should use the dremel tool or just hand sand it with some real fine paper or what... any input there?

thanks,
chris

[ILUVMY88CABRIO]

Yes, reset the TPS. As for polishing the inside, use what you want. Use a dremel if you are going to take off a lot of material.

[pengaru]

FCmaniac, on Feb 2 2003, 04:30 PM, said:

I just finished the mod on a spare from the FC3S-pro instructions.  Did you guys who have done it go through the TPS set up when you put the TB back in?  I was also wanting to polish the inside real good to smooth it out.  I was wondering if I should use the dremel tool or just hand sand it with some real fine paper or what... any input there? 

thanks,
chris

I started mine out with first having a welder fill in the holes, then used a rotary tool (dremel) to remove the large chunks of material, and after that was finshed... I spent a long time hand sanding with some high grit wet/dry paper, it's a similar appraoch to polishing the external surface, this just has more purpose. I don't recommend stopping after the rotary tool because that will leave small grooves in teh surface perpendicular to the flow of air, finish with the sandpaper in a reciprocating motion moving along the direction of airflow. Even though the surface will look and feel smooth, it will still have small grooves scratched into it... it's better to have them going with the flow.

[silverrotor]

I simplified the TB Mod by simply just removing the Secondary Plates. I kept everything else Intact. Doing It this way, allows me to still keep everything Intact and not have to hold the gas down for fear of bogging out. Fini!

[pengaru]

For those asking about the bac here is the low down.

the BACV deals with more than just idle when AC is on, the BACV tries to maintain the idle in general, it's not directly associated to AC.

If you turn on a blower motor, or headlights, or defroster, or roll up / down a window (power windows) the idle will fluxuate due to the varying load applied via the alternator.

The BACV is the ECU's way of counteracting the varying load by fine tuning the amount of air getting to the engine. Without the BACV your
idle will dip when the load varies at idle, and possibly even die.

You can easily keep your BACV, even with an aftermarket ECU like the haltech E6K. It has a target RPM, and uses the BACV to keep it at that target.

The coolant hoses can be eliminated, and plugs can be used on the water pump housing and rear engine housing. Then just remove the part of the BACV that has the coolant passage on the BACV, it's screwed on with two phillips screws if I remember correctly.

[Baldy]

any proven downsides to using jb weld? I'm gonna do it this weekend, if not today

[pengaru]

i've read about people using JB weld on the holes in the throttle body, I personally don't like it because if part of it comes loose and is sucked into the motor... you could damage things. It's not that much trouble to bring the throttle body to a local welding place that does TIG and have them fill the holes for $20.

[Apex13B]

i used large pipe plugs (7/16)..the brass insert on the radiator side (front of car) of the TB spun on me, even with boelube on it...welding it will be the best and most complete solution

[FCmaniac]

Apex13B, on Feb 15 2003, 03:26 PM, said:

i used large pipe plugs (7/16)..the brass insert on the radiator side (front of car) of the TB spun on me, even with boelube on it...welding it will be the best and most complete solution

Apex, I had a problem similar... after tapping it exactly per the instructions on fc3s pro, I put in brass plugs and on the one TB, they went in too far so I had to grind down the extra on the inside. I may remove them and weld it.

I just finished the mods on two TB's and now I'm polishing the bores with my rotary tool and polishing compound. It smooths everything out good for even better air flow.

[Baldy]

on my n/a, I didn't have to remove the tps...do I still need to reset it or adjust it? It was less complicate to get the shaft out than described.

[Baldy]

ok, I got a welder to fill the holes. on the inside, there is still a hole about 1/8" deep, but it's plugged to the outside. Should I bother with this, or just go with it since it's less restrictive than the butterflies that were there?

[pengaru]

did you have the welder fill the hole from the inside or outside?

you should have them weld it from the inside of the throttle body (thought this was obvious) then you will have a booger sitting there but it will be sealed, you then grind it smooth like you're porting it. When all is said and done it's like the double throttle never existed.

[Baldy]

He did it from the outside. If I put JB weld in the remaining hole, there is no way for air to enter from the outside, so the JB weld couldn't get sucked in...right? It would have to overcome a vacuum from behind the JB weld, right? I'm just kinda guessing...

[pengaru]

I'm not sure, I've never used jb weld so I don't know how well it would bond to the inside of the hole.

They will still experience vacuum, all of the inner surface of the runners experience vacuum... think of a straw when you try suck a thick shake through it and the walls collapse.

[Baldy]

yeah, I know what you mean, but there won't be the greater atmospheric pressure forcing from the outside of the JB weld due to the welded All

or maybe I could just smooth out the area before and after the holes with the help of Dr. Emel.

[Baldy]

nevermind about the jb weld...earlier today I read a post on the other forum about a guy's engine dying, then the rebuilder finding bits of jb weld in with the rotors...