[Jasper]

i ALWAYS see people posting up about these, asking every question imaginable.
(please, if you quote me, dont quote my WHOLE post, as i dont know how much bandwidth photobucket is actually gonna give me. if someone can host these for me, lemme know)
well, this thread isnt for that. i'm not going to go into the details about how they affect idle, performance, are they worthwhile (imo, yes), or any TECHNICAL data. all i'm going for here, is to show you HOW to do it.
tools you will need:
large air compressor (i use a 26gallon / 8.4SCFM @ 90psi, and running my die grinder continuously @ 50psi, i'd have to stop periodically to let the compressor catch up)
pneumatic die grinder (i use the $15 Husky h*me d***t special, worked great for almost 2 years now, and countless sets of TGVs, manifolds, turbos, etc etc)
carbide burrs (not NEEDED, as this is aluminum, but makes life 100x easier). i did MOST of the work with a single-cut tree-shaped bit. a double-cut or aluminum specific burr would be better (less galling)
can of WD40 (or your preferred cheapo lubricant. WD40 is cheap, and works great, and i had a spare can of it)
flapper wheels: i use 1"x1" 60grit and 80grit. you CAN use 120grit if you REALLY want, but its not necessary). plan on using at LEAST one whole 60grit and one whole 80grit wheel. i DO have a homemade porting tool that cuts down on this, but thats another thread.
time: this will take you a solid 2-3 hours to do correctly.
disclaimer: not my fault if you screw up, blah blah, removing emissions equipment is illegal, blah blah, etc etc, this is a guide only intended for professionals, etc etc.
note: you will have to find your own way of sealing up the holes. you can use a tap, brass plug and JB weld, or you can weld the holes shut (its cast aluminum), use alumaloy *TMS has had great luck with this*, or simply reinsert the rod to avoid that dreaded CEL. if you want more details on these methods, PM me, or SEARCH.


step 1: remove your intake manifold (leaving the TGVs on during this process makes its easier). not gonna explain this one. if you cant remove the manifold, DIY TGV deletes may not be for you.
step 2: remove TGVs from manifold. set one in a vice, as you dont want things jumping around on you.
step 3: remove the stepper motor and sensor. (i suggest sensor first, just because it is rather delicate, you'll need a SMALL phillips head screwdriver for this, and probably some PB Blaster). to remove the stepper motor, it's an 8mm or 10mm (can't recall)
(sensor, removed)

(stepper motor, removed)


step 4: you need to remove the screws holding the flappers in place. this can be tricky. it's IMPOSSIBLE to simply unscrew them. they are peened over at the factory to prevent them from falling out and being ingested into the motor (a la, Nissan Sentra style). you'll need to grind the back of the screws off before you can attempt to do this.
(before)

(after)

now, you MIGHT not be able to actually remove the screws. if thats the case (or you strip it), a 5/32nd's drill bit is nearly the EXACT same size as the screw (just a hair larger), and is perfect to drill them out (in which case, grinding isnt needed).
final goal:


you can now remove the flappers.
now, its time to remove the rod.
step 5: reposition the TGV housing in the vice, with the tab-end of the rob facing up. take a hammer, and give the rod a few gentle taps, then a good whack. it should pop out rather easily (it's pressed in, beware)

step 6: the porting can begin!
now that you've got a clean stripped TGV housing, its time to get started. we want to remove the divider wall, and the lip that the flapper used to stop on. now would be a good time to get those gaskets, and mark out how far you're going to port the TGVs (i typically dont enlarge the housing too much, because unless you're porting the heads too, you end up with a pretty good sized step, and reversion = evil, especially when it's a 1/2" beyond where the fuel injectors are spraying.
wall to remove:

lip to remove:


step 7: the porting actually begins now. to remove the wall, i just used the carbide burr, and cut a slot in the divider wall.

you'll have to flip the TGV housing end over end a few times to accomplish this, but the final product looks something like this



now, if you have an airsaw with a long blade, you can use that too. i just prefer the control of a die grinder over a sawzall or something like it. a mistake with a die grinder doesnt remove a ton of material. a mistake with a sawzall can send ya to the hospital, so be careful.

the rest is rather simple. you take down the lip where the flapper sat, smooth out the ridges you left in removing the dividers, and enlarge the whole housing just a bit.
you then start with a 60grit flapper (or a stone, or a cartridge roll, as another intermediate step, i used a homemade cartridge roll setup), and begin smoothing. your goal is a slightly rough surface. mirror-smooth is actually bad for flow (thermodynamics major, chime in here). your final results are typically quite gratifying


before and afters



a big thanks to TheMadScientist, as he's the one who originally showed me how to do this.

[H4N]

Nice write up!!!

[mxpop]

Nice,

Any drawbacks to eliminating them?

What do they do when stock?

[dareseven]

Nice how to! Good stuff.

[Jasper]

Originally Posted by mxpop

Nice,

Any drawbacks to eliminating them?

What do they do when stock?

rougher cold start idle (fine once it warms up), and obviously the CEL (no excuse, enginuity is free and can disable it)


stock, they're used for cold start emissions. i've done the "right thing" by running a highflow downpipe. everything else? gone.

[sti_rules]

I wonder if there is a way to remove the divider wall, leave the lip, thin out the shaft and knife edge the plates?? This would likely give the best of both worlds, ya think? OK, it wouldn't flow as good as everything removed, but still quite a bit better than stock I bet.

[JJ18Sniper]

Awesome job pulling a DIY on the TGV's. In regards to where the flappers were on the sides, what did you fill the hole with?

[mxpop]

Anyone have before and after dyno pulls with this mod alone?

Will it effect a custom tune?

[snorky]

What did you fill the holes for the plate rod with? The holes are the reason that people get this done by a professional... or atleast thats why i did.

[Jasper]

you can use alumaloy, have the holes welded, or just drill/tap/plug the holes from the outside.

the holes themselves make absolutely no difference in flow. they're too small. if it bothers you, any compentent welding shop can fill those holes VERY easily. the holes between each runner makes no difference either, as they are pre-injector, and fuel cant pass between, and each runner is under the same pressure anyways.

[snorky]

It's not about flow or injector location. It's the air leaking from the open holes where the rod used to be. You can't just put the motor and sensor back on to plug the holes.

[Jasper]

Originally Posted by snorky

It's not about flow or injector location. It's the air leaking from the open holes where the rod used to be. You can't just put the motor and sensor back on to plug the holes.

actually, you can. and theres NO NEED to worry about the holes BETWEEN the 2 runners. it doesnt matter if air leaks from side to side. if you're anal-retentive, you can seal em, but its not needed. AS I SAID BEFORE, you can weld em, use alumaloy, tap/plug them, or machine caps, as i did. (you can try just leaving the rod IN too. it wont make a damned bit of a difference)

i personally used the machine shop @ work, and made aluminum blockoff plates that i machined the proper ring into, and reused the factory gasket to seal it. i then proceeded to pressure test it to 85psi. held like a charm

(example of my TGV caps for the stepper motor, reusing the stock gasket)




i'll take better pics on the next set i do. i just got a Nikon D50, so quality of pics should be MUCH better.

[snorky]

looks good. how are you taking care of your cel?

[Ooie]

Please dont flame me...


What exactly does this do for your car?

[snorky]

the TGVs are a bottleneck in the intake system. Removing them improves flow. They are purely for emissions. Other than the US and Canada, no other market has them.