Question about modding HX35 for twins

turbodon

turbodon

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Joined
Jan 11, 2011
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39
Ok so I pulled the super B special, and I'm going to start working on my twin set-up.
For the first time around I'm going to use my HX35 over most likely a Ht3b, S472, or S475 (havent decided yet) but most likely it will be whatever I get a deal on. That and I still need to do a little research on what will be best for towing.

Anyway, the question is, on the HX35 sould I drill the wastegate hole to 1'' and then just keep on going and then drill right through the divider so all cylinders get gated?
 
Im still running my stock wastegate on my hx35 twin set-up, with-out issues.

My set-up is hx35/s400, im building about 65-70lbs of boost.
 
I punched the wastegate out as large as I could then cut the throat back in the devider as far as I could reach in the stock housing with a drill and dremel tool. EGTs were decent but you could definatly tell that there was a restriction around 3k RPMs. It spooled a S475 decent but left alot of power on the table compared to a S362/65 with a small housing. The S300 makes less boost (restriction) but really cleans up the tailpipe in comparison with only a slight spool disadvantage.
 
the twin build is in progress.
my little HX35 got a new wastegate flapper.. used a 37mm volkswagen exhaust valve as compared to the stock little flapper that limits the wastegate size to around 15/16'' hole. the hole is now about 1 5/16'' and the divider in the housing got wacked down. Now Im pretty confident that this 12cm housing will light quick and the gate will pass plenty of exhaust gas into the primary (S475 83mm turbine 1.10AR) to get both turbos lit quick and keep drive pressures down.
Also putting a 60mm 6 blade compressor on the 35 so that the primary has less restriction pushing air thru the secondary.

Cant wait to see how it runs
 
It wouldn't hurt, mines been drilled out and has a bigger flapper.

-Dustin-
 
mehhh
I wish
Still running my hx35/40 hybrid. all by itself.

I got an he351cw that has been sitting in the garage for a while, i finally got around to pulling it apart and porting the wastegate hole out and got it back together a few nights ago. i also got rid of that big nasty electonic actuator that hangs of of it by whacking it down and tigging a little plate onto the end of it that way the wastegate works mechanically.
I also bought bigblues garrett GT42

So the plan is to hang it under the 351, and hopefully the ball on this is gonna be rolling real soon. I have been hung up for the last couple months on getting my sandrail dialed in, now thats out of the way its time to do the truck up.
 
well. I finally got my butt in gear. my ricer buddy was begging me to sell him my hx35/40 hybrid to put on his mitsubishi gallant.

So I pulled the old hybrid and got to work on the twins. in the last couple days ive managed to port my exhaust manifold, get it back on (flipped) took a week to get exhaust gaskets from cummins cal pacific which was pretty pathetic on their part IMO.
got my hot pipe made, hung the gt42 off the he351. fabbed up a down pipe and a cold pipe from the gt42 to the 351 inlet. just gotta get a pipe made up to go from the 351 outlet down to the intercooler inlet.
other than that i still have to punch a hole in the oil pan and weld in a bung for my gt42 oil drain and get some silicone hose and t-bolt clamps.
hoping to have it running in a week if time permits and i can get parts in time.
Im thinking it would look sweet if i painted the cold pipes "cummins beige"
the hot pipes will be wrapped with dark grey header wrap to try to cut down on heat in the engine compartment.
 
a couple of cell phone shots ive snapped along the way. (cause pics are always fun for the forum right)

2011-12-26_14-56-26_682.jpg


2012-01-08_21-59-28_944.jpg


2012-01-08_15-05-19_872.jpg
 
well it runs!!!

got it fired up tonight
spools super fast and takes off like a bat out of hell.

it been drizzling here so the ground was too wet to really get on it, but this set-up feels SOLID
 
The sound of the GT42 getting wound up sounds pretty unreal too i might add!:ft::ft:
 
Man Im already regretting how few I took.

Im pretty happy with the way it all came out. And I even managed to do it all for less than a grand!

Its all homemade by me, mostly tig welded.
as you can see the 3.5'' pipe feeding the 351 is almost bullet shaped. unfortunately the tube shop close by me only had 3.5" u bends on a 7'' radius which was not tight enough so i had to cut a pretty good section of the center out of that one. the other pipe out of 3'' and 4'' worked great with the tight radiuses.
The last thing i need is to ditch the temp. hose clamps and get t-bolt clamps for the silicone couplers and get an air filter with a 5'' inlet.

twins.jpg
 
some randoms of the cold pipes. (boring i know)
the only other pics i took during the fabrication process..
twins2.jpg


twins3.jpg


next ill have to post pics of everything in daylight with a real camera of the finished product and maybe since im getting new tires in a week i can get a clip of me smoking the old ones down:lolly:
 
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