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he351/s475 twins?

12K views 29 replies 10 participants last post by  patracy 
#1 ·
My brother has his stock he351 from his '06....would the he351 be better than my hx40 in my twins setup? and i would assume i would have to run an external wastegate. is there anything else i would need to run this? would it even be an upgrade?
 
#4 ·
the only thing i can see is the 9cm exhaust housing will limit top end but by how much? but im sure the spool up would be great!
 
#6 ·
gwhammy has a he351 over a ht3b. i know that the he351 spools fast and cools good but i would think that the 9cm turbine would be restrictive but i dont know too much about that turbo.
 
#7 ·
Spoolup is good with this setup. I'd say it will start making boost about 300 to 400 rpm's quicker than the 40. I can have around 12 to 15 lbs. of boost at 1500 rpm's. Drill the wastegate out to 1 inch to help make up for the small exhaust housing.
 
#8 ·
so i would be back to my stock spool up i started to light at 1400, now i light at 1700.... you dont run an external gate? i thought the he351's are electronic wastegates?
 
#10 ·
now if i were to go to this setup with an external gate, my top end wouldn't be effected would it? cooling and power wise
 
#13 ·
I drilled the internal gate to 1 inch and put a spring control on it. Haven't had any problems with this setup. With the cold pipe unhooked from the big turbo I can completely control the he anywhere I want it. I have tried from 18 up to around 32 out of the he. It seems to work best at the 28 to 30. It seemed a little slower spooling when it was set at 18. I'd like to have a 22 cm exhaust housing for the 3b, I think this would help bottom end spooling some.
I have another setup like this with a hot pipe and cold pipe and 3b with 27 cm housing I'm thinking about getting rid of. I'd like to try a he on top of a k31 or 71 mm s400 with a1.10 exhaust housing. I'm looking to see if I can build a quicker set with maybe even a he341 as the little turbo.
 
#16 ·
I drilled the internal gate to 1 inch and put a spring control on it. Haven't had any problems with this setup. With the cold pipe unhooked from the big turbo I can completely control the he anywhere I want it. I have tried from 18 up to around 32 out of the he. It seems to work best at the 28 to 30. It seemed a little slower spooling when it was set at 18. I'd like to have a 22 cm exhaust housing for the 3b, I think this would help bottom end spooling some.
I have another setup like this with a hot pipe and cold pipe and 3b with 27 cm housing I'm thinking about getting rid of. I'd like to try a he on top of a k31 or 71 mm s400 with a1.10 exhaust housing. I'm looking to see if I can build a quicker set with maybe even a he341 as the little turbo.
What do you mean by spring control? can you elaborate or get a picture or something?...does the wastegate cover, cover the 1"hole or is that something you need to change?
 
#19 ·
I know the wastegate, in stock form, is better than the HX-35's but even ported I do not think it is adequate enough for twins. Most guys use a 38mm external gate and some feel that it you should go even bigger than that. 1" is only 25.4mm
 
#22 ·
Can you enlighten me? Maybe throw some facts in your post? Maybe some drive pressure numbers to prove that an external gate really isn't needed?

And what do you mean:
skneeland said:
or talk to some of the people selling kits for this application that have experimented with external wastegates on this setup....
Are you saying that external gates are not worth it or something? I would think being able to tune your wastegate would be a lot better
 
#24 ·
if you make the wastegate hole bigger it will help. with my hx35 14cm turbine over ht3b has a 1:1 ratio and cools great. with the hole bigger it will do a world of difference.
 
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#25 ·
check some of these places:
WICKED DIESELS, WICKED DIESEL
Source Automotive Performance Diesel
Untitled Document

any of them will give you info and sell you parts you want for the setup. originally i was concerned and had planned to do an external w.g. , but after talking with Nathan at MPI , i didnt feel it was worth the extra $$ and fab time.

will an external w.g. help? im sure it wont hurt, but it can be done without. ive seen dyno #s from this setup in the 800hp range.

with my current setup(smarty/TST stack)basically sucking every hp out of a stock CP3 (assuming 500-600hp worth of fuel tops) i can hit 50-60psi boost. i dont have a drive pressure gauge hooked up at the moment, but it should be right around 1:1 On my daily driver setting (approx 400-425hp) i can tow my 12k trailer all day long and wont go over 1150 deg.
 
#26 ·
with my current setup(smarty/TST stack)basically sucking every hp out of a stock CP3 (assuming 500-600hp worth of fuel tops) i can hit 50-60psi boost. i dont have a drive pressure gauge hooked up at the moment, but it should be right around 1:1 On my daily driver setting (approx 400-425hp) i can tow my 12k trailer all day long and wont go over 1150 deg.
If you're still running the HE351, I can assure you, you've gone outside that 1:1 ratio once you went past 40-45psi.
 
#27 ·
I welded a simple bracket to the exhaust housing and got a spring from the local hardware store. I got lucky and the spring worked right out of the gate. It is easily adjustable. I haven't took the he over 32 lbs. of boost as this is enough for the twin setup. With way more fuel than it can burn the he by itself will not go over the set boost. I'd planned on putting a exhaust pressure gauge and secondary turbo gauge on it but laziness has prevailed since they are working so good.
On wastegates, the b1-b2 setup I used to run had a 22 mm external wastegate on it with no wastegate on the b1.
I have run a 38 mm external gate on a hx35-3b setup but the piping starts to get complicated and I really like simple. I'd say if you were taking these to the max a bigger gate would be needed but this is more of a towing setup for me. I hardly ever take them over 45 lbs. of boost with normal driving.
I tow heavy alot with this truck 24 to 34,000 and it tows great with the 200 horse injectors. This I think says alot for how these twins work. I think a smaller turbo like a k31 or 71 mm s400 would be better this is just what I had laying around to build with.
If you are towing and pushing boost up above 50 lbs. I feel you are asking for trouble, that's just to much load for vary long on these motors.
 
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