A few pictures of the "custom" .... home made He351ve turbo setup. I purposely used about 3-1/2" of 2-1/2" exhaust pipe to move the turbo down to make an easy connection for the cold pipe. I added a little piece of "L" steel top and bottom to help support the load, especially when it might see 2000* F by the end of a 1/4 mile run.
For the downpipe I used some scraps of 4" EMT electrical conduit that I scavenged from a trash dumpster on one of my construction sites. I mitered the angles and fit them as best I could. Then I "dry-fit" all of the exhaust downpipe using 3" pieces of metal strapping and sheet metal screws as gussets. Once everything fit and looked to have adequate clearance, I removed everything and welded up the joints with my cheap harbor freight 120volt flux core welder. After welding, I reinstalled the gussets to help support my less than professional welds. The 4" EMT has an inside diameter of 4.25" so it still has plenty of flow without nice mandrel bends. The exhaust system ends just short of the rear axle since that's where I ran out of free conduit.
For the oil supply, I reused the stock line and removed the threaded adapter fitting from the stock HX35 and threaded it into the HE351. For the oil drain, I reused most of the stock steel 3/4" drain and just cut off the last few inches that bend down 90*. At the block, I reused about half of the steel nipple insert and cut if off just before it made a 90* bend. I then used a 6" piece of 3/4" fuel line from a big rig shop that I had left over from another project a few years back.
For the cold pipe, I removed the stock cast aluminum elbow entirely and just used the stock 3" bent cold pipe. To make the cold pipe line up correctly, I flipped the stock pipe around so the shorter leg of the bend was directed to the charge air cooler and longer leg directed toward the He351ve's discharge. The cold pipe and turbo discharge met at a perfect 45* angle so I bought a $20 silicone 2.75" to 3" bending 45* reducer from siliconeintakes.com. I also had to buy a 2.75" t-bolt clamp for the turbo outlet.
To control the variable geometry housing, I welded up a small frame out of 3/4" angle steel and drilled to holes to line up with the bolt holes on the HE351ve body. I was able to reuse the 5mm allen head bolts from the He351 as well. There is an adjustable bolt that limits how tight the exhaust housing can close down. I then have a heavy spring that I mounted onto a peg that's mounted onto the stock control arm and an adjustable turnbuckle on the other end. There is a second bolt mounted vertically on the center section that I use to control the maximum opening size of the exhaust housing. If you take careful measurements on the inside of the housing and the moving parts, it's apparent that the housing is able to open too far to where it creates a useless cavity behind the turbine wheel. At my current level of fueling, the difference between maximum opening and say 75% open is only 2-3 psi boost, however the motor does run a little freer when it's allowed to open in the 90%+ range.
As I'm sure everyone has seen on youtube, you can close the housing down so tight that it screams/whistles at idle. I test drove and a lot of different levels of tightness and although really tight does make the motor have a lot of torque at idle and great throttle response like a gas powered v-8, it kills the mid range and creates excessive smoke and turbo lag.
With the housing a little more open, the off-idle response is just like the stock turbo with a little more lag in the lower mid range but a much much firmer hit when the turbo fully spools.
For example, with the stock turbo and identical fueling/AFC setup, from a dead stop: WOT will spin the tires half way through 1st gear and most of the way through second. The just a small chirp going into 3rd.
With the 351ve identical fueling/AFC setup, from a dead stop: WOT will chirp the tires a little in first then seems to experience turbo lag till second gear. Instantly when the TQ locks in second the turbo smacks/spools hard and blows the tires off through all of second gear and half way through third gear. This turbo feels like it added 25 HP with my current fueling and it does run really clean when boost passes 30 psi. Max boost right now holds 38psi and spikes to 40psi on the 3-4 shift.
