Enough mental mastication, already! Finally, the fun has begun. <img src="/forums/images/graemlins/kewl.gif" alt="" /> I can only hope it runs well when I've finished. If noodling/doodling time counts, it should be fine after a whole lot of work. In the end, you have to build it, see what happens and adjust accordingly - the essence of backyard/shadetree hot rod effort. I'll post pictures and comments as I go, but since time is scarce, there may be considerable gaps in progress reports.
Bob (87_Montero) was kind enough to bring an engine to me to use for prototype work and it's now on the perch. When this is over, I'll freshen his engine in exchange for his effort.... thanks, Bob! <img src="/forums/images/graemlins/kewl.gif" alt="" /> Sparkem sent a lower intake and fuel rail.... thanks Sparky! <img src="/forums/images/graemlins/kewl.gif" alt="" />
The design goal is simple - add some torque and resulting HP to the 3.0L to give it a little more ability to pull hills in O/D with tires larger than 31s - without resorting to an engine swap (4.3L) or gear change.
How much power? The target isn't set in stone, but if this engine can be increased from 168lb-ft/143HP to ~225lb-ft/190-200HP, the difference should more than do the job.
2) Easy to tune and repair
3) As near to OE parts as possible without computer changes/add-ons, etc. - work with existing ECU
4) Use of OE fuel pump (don't yet know about that)
6) Sized to not require major engine modifications for durability (I guess that depends on what you call "major" <img src="/forums/images/graemlins/wink.gif" alt="" />)
7) Relatively inexpensive - this one won't be realized on this project, but should be reasonable compared to the cost of similar aftermarket packages for other vehicles, since a new 4th Gen unit with internal bypass will be used.
8) Retain stock cooling fan
9) Retain good "drivability" manners
10)Can be duplicated by anyone with good mechanical skills and access to machine tools
Here we go -
The first challenge is the fuel rail interfering with overall package height considerations. I got a spare from Sparkem, but found that there's a difference between the '89 and later 3.0L rails. Note the difference in crossover tubes - the '89 rail is on the left, the later model on the right:
So, I'm using my '89 fuel rail.
The rear of the fuel rail also presents problems for installed height since the fuel pressure regulator is mounted on top of the passenger side rail and the fuel inlet is also raised:
Both have to be dealt with, so they were removed, the regulator hole welded/ground/puttied (it'll be sanded and painted later). The inlet and outlet rail ends were tapped for a 1/8" NPT fitting which may have to be bored out to .260" in order to not be any more restrictive to fuel flow than the I.D of the front crossover tube:
Here's the modified fuel rail sitting on the lower intake:
I thought about setting up the drafting table in the garage to draw a shop blueprint, but realized it would be easier and faster to make a wooden prototype which is now under construction. It will be used as a reference piece to construct the finished part in the machine shop. Here's the first piece - a 1.375" flange spacer that extends the intake ports up to a level that will clear the modified fuel rails and will support the S/C outlet plenum:
Here it is in place on the lower intake:
Here's a side view that shows 1/8" clearance above the fuel rails:
Now I'm off to Lowe's to get a piece of plywood to make the plenum and S/C plate.