I set out to make a ported intake manifold for my 3.0 I started by cutting it in half in order to port the bends from both sides. Once I get that all done Im going to port the straight sections and then have it welded back together.

So who thinks Im nuts?

Im about half way done with the bends section. Only 3 more bends to go but Im getting faster at doing them.








What else ya gonna do with an extra 3.0 manifold? Thay dont even make good boat anchors <img src="/forums/images/graemlins/kewl.gif" alt="" />

Im using a 1 3/8" freez plug welded to a long 1/4" bolt for a guide. I do all the rough cutting to the freezplug size all the way through then just smooth it all out after that with a 60 grit flapper wheel. Its not perfect but after seeing the intake valves and the lower intake its clear that the upper intake is quiet the bottle neck. I plan on running the truck with the ported manifold and the stock throttle body. After I get a good feel for it I will put the bored throttle body on and see what if any I gains I get. I may try the bored TB and the stock manifold combo just to see what kinda results I get.

Im hoping EB and any other engine performance guru's will chime in here with some thoughts. If this dont work I will be using steel and making a whole new manifold using butt weld steel 90's and some thick plate for the flang.

Question. When you weld it back together, how are you going to weld between the tubes to keep them from crossing over from one tube to the other?

I say buy a used TRD Supercharger and weld the 3vz-e runners to it. Woila...considerably more power!

By the way, does the 3vz-e intake manifold really have 12 runners (six for low rpm and six for high rpm?)

Good one.

I didnt really consider that tiny bit of air between the runners that significant. The manifold will be complete and sealed. I guess I will have to wait till its together and on the truck to see if there are any noticable losses due to a small chance of air between the tubes. The amount of vacuum in the tubes should be down considerably from the stock manifold. The lower intake manifold has about the same diameter runners as the ported ones on my manifold. In stock form you have small runners on the upper intake feeding the much larger ones on the lower intake. I have seen several other manifolds on motorcycles with a crossover tube near the heads so I doubt there will be any major performance losses as long as I make sure the pieces mate up well before welding them.


Will it work? I have no idea but atleast Im being creative with the 3.0 as opposed to just throwing my hands up and saying "Its a slug but we really have no good reason why" like most other people.

Hopefully that works out for ya. I'll just sit back and wait to hear the report. My trucks been running awesome since I got the motor done. It really loves being above 3000 rpm and pulls harder then hell.

ev88toy4x4 do you notice your valves being much louder with the DOA cams? I have adjusted mine 2 or 3 times (little or no adjustment needed though) and the damn things are still loud. Tim thought it was due to the headers allowing the valves to ring a little easier than thay would through cast iron. Mine pulls plenty strong above 2500 but like any one I want more power <img src="/forums/images/graemlins/nana.gif" alt="" />

Im also going to cut the head pipes back from 2" to 1.75" or 1.875" after I finish with my manifold testing. I am thinking that 2" head pipes are a bit much for the small displacment 3.0 and I think exh velocity would improve with smaller head pipes feeding the 2.5" exh system. I may get a little more low end torque with the potential increase in scavanging from the increased velocity unsig smaller head pipes. I need to route it behind my xfer case any how.

There is no such thing as "Too much Power" just pilot error <img src="/forums/images/graemlins/smile.gif" alt="" />

Good point. I bet it will run (as long as the outside if sealed), just not very well. Hey Ganoid, let me know if it doesn't work well, I've got an almost complete '93 3.0 in my garage. I'll sell ya the manifold. Or, I'll give you the whole thing if you come take it out of my garage!

They are a little louder then they were before, but I dont think it is anything to worry about. That header/cast iron thing might be true too about them. I have the cast iron manifolds still. But it pulls pretty good from 2500-3000 and all the way up. Ive only taken it up to 4500, im afraid to go any farther, lol. Its frickin loud as hell with my exhaust.

I would have much rather used mandrel bent pipe and built a complete new manifold as thief suggested. The only problem is I have no source for such bends. I looked into extrude honing but that was gonna run close to 500$ based on the pricing on thier web page I think Im in for about 25$ in sanding wheels and a new sawzall blade. I dont know if any one has paid attention but in stock form the upper intake has significantly smaller runners than the lower does. In hopes to maintain diameter Im using a 1.375" dia freeze plug welded to a long piece of flexable steel for a guide. Once I get the plug to clear 100% of the runner length I simply put the sander on and clean up everything. I know its not rocket science but Im hoping it leads me in the right direction. I have only 1 of the 90's left to port then its on to the straight sections and those should go fast.