Thats a problem then since the computer is thinking its only at 88% opening. even if you are sure the tb is open at 100% your car is not running to its capabilities because it is never able to get to its WOT table.

 

I see two solutions for this. PCM tuning or in-line electronics to correct the input and output voltages. Neither of which will come easily. I honestly don't see any of the tuner software guys putting much effort into a fix. Bigger fish to fry.

I'm not an electronics guy either but have a couple of buddies that are. One loves a challenge. Somehow map the stock 78mm voltages and build something that corrects the 90mm voltages.

Maybe machining a 90mm housing that the 78mm internals will work in?

I'm not optimistic

 

i think its n the tune myself. i still say there are many tables i've seen that deal with the tb.

 

Ok...I am a EE major...I can get my hands on a DBW GTO and I think a DBW truck. I can also get my hands on a O-Scope and multi-meter to find out how the TB is driven. I am going to assume it is by current (easiest way in my my mind). Let me see what I can do..

 

That would be great. Possibly profitable if you could come up with something. As it is now before I could even approach my electronic buddies I would have to purchase a 90mm TB to work with. Kind of hard to throw more money into this mod knowing it's not 100% functional.

I also have some machinist buddies and a spare 78mm TB. I'm really beginning to think this approach may be the best route for me to try and persue. Machine a new housing that you could swap over the 78mm motors and electronics to. Just attached to a 90mm blade. Dunno. Need to get a 90mm TB in my hands.

 

Ok.....I read all the posts here. Been told to definately do the 90mm TB and J-tube mod to my LQ9 6.0L VHO Radix'ed Silverado.
I ssume these issues would be present with my truck as well.
With all this being said, I'm guessing this mod would not be worth it at this time then.
Guess I will wait on the electronics wizards to see what they can do first.
So what's the hype with the 90mm TB & J-tube upgrade all about? What kind of increases are you guys seeing with it over the stock TB and J-tube?

Jim

 

Throttle position is controlled through Pulse Width Modulation of the voltage to the Throttle Actuator Motor(similar to fuel injector operation). I would like to know how the PWs seen by the two TBs in stock configuration compare at WOT.