Anyone have any figures using larger TB (72-74mm) over stock?

Thanks

 

Wouldn't that cause major turbulence?

 

Not on FI it wouldnt

Iuse a 74MM

 

I am going FI, starting the build now. Any experience, impressions with the BLOX

TB's, they're making one @76mm probably straight bore no taper. Increased low end torque?

 

ProFlow has a dyno comparison, I think they show 12whp gain using a 70mm TB on a Compteched car. Nice gains from 5K to redline if I remember right.

 

^ If that is correct then for us turbo guys it should bring the hp line up accordingly once we are spoled. Good find I may look into this.

 

Proflo dyno 12 hp and 5 ftlbs.

BLOX billet TB on Ebay for $188.00, I think. Sizes from 68mm-74mm. They make a
76mm not listed in sale. I emailed to find out about availability. Just open up the intake. Good price.

 

Be careful, with Blox or there counter parts.

I had a TB just like the Blox. (Made by the same people, same factory)

Anyway, I cant be 100% sure what caused the break, but I was in a pull and the TB came apart on me. The piece of metal running through the TB holding the butterfly in place (It has 3 screws) broke, causing the spring to fly off and the cable to disconnect.

This scared the S@#$%^ out of me....LOL

It could have been a bad part from the mfgr? Could have been a bad piece? Could be cheaply made?

Might not be good for almost 500hp? Another thought we had was, I am running a Type s Greddy BOV, SO....it might be too small, causing more than normal back pressure on the butterfly area, and while shifting....opps?

I dont know. SO, I ordered a Skunk 2 70mm TB and a new Greddy Type R BOV.

 

If I did the math right, which I probably didn't, a 70mm should have a cross section
of about 6 inches. Putting a hypothetical 20psi boost against that butterfly would produce about 120 lbs force? Now granted the engine is turning and the BOV should be relieving that back pressure but it's something to look into. How much force can those shafts support before grenading? How fast do the BOV's respond.
It's been along time since I've been around a Turbo in a car.

 

Just a reminder that the larger the throttle body the greater the difficulty in modulating the throttle at low speed. I have a 70mm and it is difficult to start moving without reving. I would think a 74mm or 76mm would be difficult to drive on the street.