I have an 89 TII motor with an agressive street port..i also have a 87 and an 89 TII intake manifold (w/ throttle bodies) SO ....before i place them into my engine bay i would like to have them ceramic coated, both for looks and to insulate against heat a little bit. So which one flows more..........in the end it will be extrude honed, but that wouldn't happen for another year or so. Please help me out with this. thanx

 

AFAIK, they're exactly the same. The NA manifold changed on 89, but not the Turbo.

 

series 4 and 5 intake manifolds are different. The series five has slightly larger ports.

 

Ok so in your opinion which one would you A) extrude hone and B) ceramic coat with a sterling finish.

 

I compared my S4 and S5 lower intake manifolds side by side and concluded the S5 has slightly larger runners. Thats what I modded.
Why extrude hone? Thats great for manifolds that are convoluted and impossible to finish w/ die griner. I polished my S5 lower w/ 10" rod split for emery cloth in a die grinder- the runners are a straight shot. Remember to rough out below the 2ndary inj. to avoid excessive mani whetting.
I am using S6 upper, which can be polished w/ die grinder as well since its runners are pretty straight. 2nd gen upper isn't so easy, I guess...

 

Thanks BlueTII......Anybody body else have any more thoughts.....? Wow this is the first thread that i've started that hasn't gotten into some sort of flaming.

 

THATS BLUE TII, BlueTII IS SOMEONE ELSE! Ha ha, just wanted to throw a little flame in there for you! The cost of Extrude Honing is so high its cheaper to swap to the 3rd gen upper intake and polish the runners by hand. I'll post some pics of my job eventually. Ian