JimS

The j tube is bolted on quite tightly and I don't think I'll be able to get a wrench on the bolts well enough to get them loose. But even if I can....

The 78mm stock throttle body has the coolant hoses going through the bottom and there is not provision for this on the new 90mm throttle body I bought from SDPC. So that means I do the bypass but I'm wondering how, or even if, the truck will run in the cold weather we have here??.

In addition my stock tb has a tube coming out of the top that is attached to a hose coming from the valve cover and the new 90mm tb has no provision for that. How important is it? Do I just put a cap on the tube coming out of the valve cover? Or, do I have the wrong part?

If I can't get the bolts loose without the wrench slipping and rounding them off I'll want to buy a j tube and have it on hand when I/we do the heads/cam so I can just switch it. I don't want to have to take the sc off twice. It's just too hard on my knee.

Last Call

iTrader: (4)

Which throttle body are you using? Do you have drive by wire?

I think the 2002 engines had cable driven throttle bodies and you should be using the UMI throttle body, right?

JimS

My 2002 had dbw, although I guess most didn't, and I bought the part # shown in the post about changing the j tube flange. Part #12570790.

DrX

iTrader: (7)

On my 2004 setup the PCV line connects to a nipple installed in the bottom of the plastic Radix intake tube just ahead of the TB. There is no nipple on theTB.

Those bolts are pretty stiff all the way out. First I broke them loose by hand then spun them out with an air ratchet. Will have to be more careful tightening them back up though. Not sure how much room you have when it's still on the motor.

I was wondering about the coolant bypass as well. How do the LS2s heat the TB?

moregrip

iTrader: (8)

I dont think they do

mattrem

iTrader: (7)

The coolant bypass shouldn't be a problem, I have had it for awhile now, its gets cold here and I haven't seen a problem. Just use a 5/16 barb connector to put them together.
That hose to the valvecover pushes are into there, just tap the intake tube between the MAF sensor and the TB and it will do the same.

JimS

Now that you mention it my Radix intake tube came with hole and a plug. I used the plug. I'll have to remove it.

I don't think I have room to break them loose by hand. I'm hoping that I can get my 1/4" drive air ratchet in there. It's either that or I buy another j tube, modify it and do the switch when I change heads, or I have to take the sc off the truck twice.

BigTex

iTrader: (16)

I just removed the short coolant hose that went to the TB and stretched the long one over to the vent pipe. Nothing else needed to bypass the TB.

JimS

I'll have to check and see if the long hose is long enough. Thanks Richard.