80MM TB to LS6 IM & IAC valve/TPS questions
02-09-2011, 11:52 AM
#1
80MM TB to LS6 IM & IAC valve/TPS questions I have an LS6 IM and BBK 80MM TB that I bought used. Apparently, there's a spacer that originally came with the TB that's actually an adapter that tapers from 80MM to 78MM. I can get the install kit that includes the spacer/adapter, gaskets, bolts, and (I think) a throttle cable relocator from BBK for $50.
Is the ~1MM "lip" that will be exposed on the IM inlet even something I should be concerned with? Could I "port" the inlet 1MM? The gasket is awful close to the inlet and I don't want to make the plastic wall that holds the gasket in too thin and crack it.
Also, the IAC valve and TPS from my 2002 4.3 TB fit the BBK TB and they plug into my CPW harness. From what I can tell online, my 4.3 TPS is the exact same part as the pre-2003 ('03+ have DBW) V8 truck TPS. The IAC valve has a different part number, but it physically fits the TB just fine. Does anyone know if the IAC valve will work? The ~2002 truck IAC valves are pricey ($60+), but I found one for around $15 shipped. It may be a typo, but I'm gonna chance it if it'll work. It's not an AC Delco or Delphi, it's "Replacement" brand.
So, should I:
(A) Save my $15 and use my 4.3 IAC valve because it will work
(B) Try the cheap one because I may/will need the V8 truck IAC valve
(C) Don't waste any time or money on the "Replacement" brand, and get the Delphi brand
Also, I realized this morning after further investigation, it appears that my LS6 manifold has already been mildly ported. I've never even had the opportunity to look at a stock manifold, but I don't think they are ground just at the inlet and outlets of the runners. The outlet ports aren't exactly straight and even on the long ends, and the "lip" that is revealed when the throttle blade is opened is smaller than 1MM and is a bit irregular around the circumference. I'd like to even out this irregularity and make the inlet match the 80MM TB.
This raises more questions. What is normally used to port poly manifolds? I was thinking about some sort of cylinder hone ("bottle brush" type) to enlarge and round-out the inlet since it doesn't need much. I also want to smooth where the grinding has been done on the inlet and outlets. I'm sure 600-1000 grit sandpaper and plenty of elbow grease is the answer for this.
Whatcha think?
Is the ~1MM "lip" that will be exposed on the IM inlet even something I should be concerned with? Could I "port" the inlet 1MM? The gasket is awful close to the inlet and I don't want to make the plastic wall that holds the gasket in too thin and crack it.
Also, the IAC valve and TPS from my 2002 4.3 TB fit the BBK TB and they plug into my CPW harness. From what I can tell online, my 4.3 TPS is the exact same part as the pre-2003 ('03+ have DBW) V8 truck TPS. The IAC valve has a different part number, but it physically fits the TB just fine. Does anyone know if the IAC valve will work? The ~2002 truck IAC valves are pricey ($60+), but I found one for around $15 shipped. It may be a typo, but I'm gonna chance it if it'll work. It's not an AC Delco or Delphi, it's "Replacement" brand.
So, should I:
(A) Save my $15 and use my 4.3 IAC valve because it will work
(B) Try the cheap one because I may/will need the V8 truck IAC valve
(C) Don't waste any time or money on the "Replacement" brand, and get the Delphi brand
Also, I realized this morning after further investigation, it appears that my LS6 manifold has already been mildly ported. I've never even had the opportunity to look at a stock manifold, but I don't think they are ground just at the inlet and outlets of the runners. The outlet ports aren't exactly straight and even on the long ends, and the "lip" that is revealed when the throttle blade is opened is smaller than 1MM and is a bit irregular around the circumference. I'd like to even out this irregularity and make the inlet match the 80MM TB.
This raises more questions. What is normally used to port poly manifolds? I was thinking about some sort of cylinder hone ("bottle brush" type) to enlarge and round-out the inlet since it doesn't need much. I also want to smooth where the grinding has been done on the inlet and outlets. I'm sure 600-1000 grit sandpaper and plenty of elbow grease is the answer for this.
Whatcha think?
