Porting your throttle body

[sx sonic]

Yea the tumblers are designed to create turbulence at lower RPMs to either 1. Promote better fuel atomization or 2. To promote better low RPM cylinder filling.

Whichever the case their is a noticeable increase in upper end pull and overrev after 5,500 rpm with the tumblers removed. Not surprising after seeing the blunt/crude obstruction they provide.
What is mildly surprising is how little (or non existent) removing the tumblers affects gas mileage or low RPM drivability.




Being a short shifter I was expecting some negative effects of removing the tumblers......... None were observed. Among all the mods in my build, porting the intake is the 2nd most noticable power adder I've done after the tune.

 

[rdss]

I guess it might be time to suck it up and get rid of the tumblers, I was planning on waiting until the warranty ran out though...... Do y'all think it will void my warranty?!

 

[sx sonic]

I guess it might be time to suck it up and get rid of the tumblers, I was planning on waiting until the warranty ran out though...... Do y'all think it will void my warranty?!

Based on my experience as a tech It's unlikely. If you did a thorough job it would even likely pass a visual inspection if removed unless the tech has done more than one and looked into (and noticed) the stock runners...... The tumblers literally look out of place.

In an otherwise stock looking engine bay I'd say It's less likely to be discovered than a trifecta tune. It just isn't probable to go under scrutiny.

With basic hand tools, an air compressor and metal working bits, ideally some polishing equipment, and no more than 5 hours (probably 2-3) you can have a ported manifold.

Two things of note are packing the runners with towels simplifies cleanup. Also the goal is to make the runners look "normal" and also smooth out any seams or transitions, after seeing the tumblers what I'm talking about will become apparent. It's not nearly as daunting as carefully enlarging and blending a throttle body or cylinder head.

 

[rdss]

I was joking sx, I am tuned with all my cats gone. But thanks for the pointers on how to get'r done, I'll probably pick up a pneumatic grinder and the proper bits prior to taking this on. I just haven't gotten the desire to spend 5 hours pulling the manifold out and grinding it and replacing it. I'll probably wait until I have green injectors to throw in to do it so it's all done at once. I'll also probably wait until the winter so I can sit in my garage and work in 50 degree weather vs 100+.

 

[egbandman]

That thought crossed my mind. I think it would help marginally, reducing the O.D. of the throttle shaft would be more effective. Had my air compressor and dremel not failed I would have done both. I'll get to it in due time.

You should be able to notice the difference of the kniffing effect at WOT, also, it'd be better to angle them while keeping one side flat. Keeping in mind which way the throtle plate opens. If you intend to grind down the plate to angle the edge, I advise taking this into consideration. Take a look at this picture I made in paint to help understand a little better.

 

[cndctrdj]

Has anyone lost gas mileage doing this?

 

[sx sonic]

I posted an all time high of 55.xx mpg with all my current mods and this (58.xx DIC). So I'd have to say no.

I need to get another picture acount because I've gone more aggressive on the porting.

-With the throttle held at WOT (I used a socket), ground the throttle shaft flatter. I removed the throttle plate screws so I could do this all the way across.


Went more aggressive in the bore, referencing the last picture of the 1st post I did the following.
-Did more blending of the "hump" in the bore, took off some material of the highest part and made smoother transitions for the incoming air. I DID NOT touch the back side of the hump, the part the throttle actually passes by since it may severely mess with how the car idles, while I'm not a %100 on this I'd rather not risk it.
-On the sides of the bore where the "hump" is almost non existent I removed it making it flush with the rest of the bore. The 3 & 9 o'clock are perfectly smooth and from ~2 & 10 o'clock blend back into that big hump.
-The "dip" at the bottom 180 degrees from the "hump" was ground completely flush with the rest of the bore. Agian most of the work to get it flush was done towards the front of the TB, away from the throttle. Once it was flush I very carefully smoothed out the side closer to the throttle plate, being very careful not to disturb the the bore where the tip of the blade passes. this was done from the 6 0'clock position all the way up to 3 & 9 o'clock.
As referenced from the last picture in OP.

 

[cndctrdj]

Thanks Sx sonic. I might be doing this this weekend along with my bov

 

[egbandman]

Would anyone know the distance between bolt holes? In millimeters on center?

 

[SouthFLSonic]

If you intend to grind down the Buy Fifa 13 PS3 Coins plate to angle the edge, I advise taking this into consideration. Take a look at this picture I made in paint to help understand a little better.

I think if you get lost loser grind the plate down you look like a complete A**HOLE and as far as your picture in paint stop wasting our time it looks great.

 

[sx sonic]

porting gbandman;191061]Would anyone know the distance between bolt holes? In millimeters on center?[/QUOTE]

Just noticed this post. The center to center of the bolt holes is at or very near 56mm. All 4 holes have the same center to center.