he351 for twins on 12 valve

H

high toned sob

No Smoke
Joined
Jan 12, 2007
Messages
209
Hi,
Hey I'm pretty maxed out on fuel now, and am wanting to do a set of twins. Here's the rundown: holley pump, studded head, marine gasket, new era 370's (correct pattern), 4k or 5k kit (haven't quite been able to decide) 60lb springs, and a cam (have not decided on this either, still looking). I have a 351 and 3rd gen manifold to use, I was going to flip the manifold, would give me plenty of room for the bottom turbo. I just don't know which one would be best.
It will be used mainly as a daily driver and fun street truck, most it would tow would be the cattle trailer or car trailer, maybe 10,000 lbs tops.

Now, my next idea is not what you guys normally run, don't roll your eyes yetLOL. I started a thread before about parallel twins, I was wanting to use two hy35's, but most said they would be too big for 3 cyl's. SO, since the 351 only has a 9cm exhaust, would that be better? Then I'm only looking a 18cm total. I was thinking of getting another 3rd gen manifold/turbo, and all you would have to do is cut off the extra part of the manifold and weld the hole shut. It would be easy to mount them. Then run a y-pipe for the cold air part, and the same for the exhaust. Could I get them to spool on the street without being crazy smokey, or could I take some fuel away a certain points by grinding my own plate? I have made a few different plates for the truck, maybe I could grind a custom profile to control fuel some?

I know most will say it won't work, but I can't believe that someone hasn't been successful with parallel's. *bdh* Maybe they won't work in a full tilt pulling/racing application as good as compounds, but I'm not looking for that anyways. I have twin turbocharged a few gas engines, so I am familiar there. BBC's, BBO's, SBC's have all loved twins, but they are also v8's.

Any advice for either idea? Big bottom charger for compounds, OR pointers, downfalls, problems with parallel?:bow:

thanks all,
Mike
 
i dont know, never tried it, i know most on the forums recommend against it, but you could always try it, if your so dead set about it lol! btw the he351 has 60 mm wheels, not very small for 3 cylinders... maybe 2 smaller chargers?

or you could do tripples! first stage is paralell and the other one compounded....
thats what i keep thinkering about, instead of a big primary two he341 or two he351
 
The HY35 also has a 9cm exhaust housing with the same wheels as a HX35. The HE341 is basically a HY35 with different compressor housing and a true 4" exhaust outlet. The HE351 is a 341 but with a 60mm compressor instead of a 54 and with an electronic solenoid that can close to block boost from the wastegate and delay it's opening until a higher pressure is reached. All of these turbos are designed to move enough air and spool for 5.9L of displacement, not 2.95. I'd see if you could find something a little smaller, like an S200 variant.
 
HY9, HE341 and HE351's all will be too large. If you are set on parellel twins look for an S200 or HX30.

Logan the compressor wheel on an HE341 is 58mm, which is bigger than the HX35's and HY9's.
 
stevewes2004 said:
i know you didnt want compounds but the he351 works awesome in a compounded setup.
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stevewes2004: i saw the writeup on your twins on CF, looks really nice!
did you try to fab the intercooler pipe beneath the cold pipe that goes form the primary to secondary? like some 3rd gen twin kit do.
jw why not, i suppose it wont work on a 2nd gen....

To the original subject...
how about two he251ve or something like that... VGTs
 
VGT's would be killer, I recently put a set of head gaskets, studs, egr delete on a 6.0 Ford, and I like the turbo on that. EASY to control on any application. Some VGT's are just way to sophisticated for all they do. I'll look for some HE251ve's and in the past I had thought about the s200's. With my engine having all the mods listed, what could I spool without alot of smoke?

Stevewes2004, yours run pretty killer? How's it run unloaded, and how is your pulling heat and power?
Thanks a bunch
Mike
 
also i think the manifold has different inlets on the cr and 12v, but i think you can grind the inlets out on the cr
david
 
12vstrokethis said:
also i think the manifold has different inlets on the cr and 12v, but i think you can grind the inlets out on the cr
david
Click to expand...

Good point.

Also to the OP - if you flip a 3rd gen manifold, I don't think you can shut the hood. I'm not 100% positive, but I definitely would check that before you get the rest of the parts to do the turbo install.
 
thanks! yea mine spools really good. i have only seen 1300* with the box all the way up unloaded. cools really good. check out my vids on youtube for the spooling shots.
 
12valvestrokethis and jrod,
You are correct on that. HOwever I'm going to be running a custom hood, it will give me 4" of extra clearance. I already have one 3rd gen manifold and one he351. One thing I do need to check is which one it is. It does have the boost solenoid on the cold housing, but it came off of an '04. I need to find the build date on the truck to see which one it is. I have pretty much checked all my clearences, and they will fit, I also have the room for two 4" downpipes.
About what rpm would I start to spool? Theoretically, if I could get some boost at lower rpm (I do have a few ideas) say a pound or two at idle, when would twin 351's light? Or are they just plain too big for a street/daily truck? 18cm housing just too much? If so, I 'll just look for smaller ones. I'd like to try it, if it doesn't work, I'm not really out a whole bunch, then I'll just go with the 351 and Ht3b.

Thanks fellers,
Mike
 
why don't people understand why this won't work? :confused:

running side/by/side twins is the exact same thing as running a big single turbo... a single HE351 will support about 500hp, so go get you a single turbo capable of supporting 1,000hp and hang it on the side of your engine and tell me how much you like it
 
Forrest Nearing said:
why don't people understand why this won't work? :confused:

running side/by/side twins is the exact same thing as running a big single turbo... a single HE351 will support about 500hp, so go get you a single turbo capable of supporting 1,000hp and hang it on the side of your engine and tell me how much you like it
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I was waiting for that. The reason I don't understand why it won't work is because I've done it before quite a few times (albiet on gas engines) and it works great.
How about a suggestion for a different set that you think would work? If 351's are to big, I won't try it with them. I haven't been on "performance" diesel's very long, so I am trying to adapt some gas knowlegde here. You obviously have a good grip on them, help me out here. Just trying to try something, I"ve got the ability to build a header if I had to, I have a decent idea on how i can get some boost at idle, and at low rpm, when would 351's start to take off? Woud they never light on normal driving circumstances, only flat out WOT full tilt full load? If so, I'll look for something smaller. I can't have a smokey hot truck. If I wanted that I'd just throw some marine 370's in it and bolt the wastegate shut.
Thanks forrest beans,
Mike

Also, I drove a "roughly" 500 hp mega cab dually with some work. I say roughly 500 because I figured out the time i could run and the wieght of the truck equalled close to 500. Anyways, it would bury the pyro at 1800 WOT and never clean up. So I wouldn't want to push a single 351 clear to 500hp and talk about it much, my luck it wouldn't last long:doh:
 
I think parallel 351's will work just fine. They will spool up a little slow but the 351 spools identical to an HX35 which runs great on a lowly 160 HP 12valve. I'll bet twin He351's would run similar in spoolup to an S300 sized turbo with a 66 or 71mm compressor and 73mm exhaust wheel.

Plus you'd have enough air for 750-800 hp.
 
you have enough air for 750-800hp at 35psi of boost... but it's on an engine that won't make that kind of power at that boost level!!!

twin HE351's would spool like an S480... maybe slower
 
high toned sob said:
I was waiting for that. The reason I don't understand why it won't work is because I've done it before quite a few times (albiet on gas engines) and it works great.
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I seriously doubt that you have taken a factory turbocharged gasoline vehicle and added a 2nd factory turbo right beside the original one and had it work great

y'all need to learn how to read a compressor map :o
 
just becuase I don't have 65 lbs. of boost doesn't mean I won't make any power does it? If you have twins pushing 35 lbs each working ez, wouldn't that be more efficient than a hot 65 lbs?
Forrest, I'm still learning all the turbo sizes, I take it a S480 would be totally unstreetable? What is the maximum "S" turbo for good street manners?
I'm thinking simpler, with two of them totalling 18cm exhaust, would it be a smokey pig until 3000 rpm? Or would it start to pick up earlier?

What did the he251vgt come on? I have been searching and can't find much info about it?
 
no, a cool 35psi isn't going to be more efficient than a hot 65psi unless you're talking about ice cold vs. scorching hot...

the 12v needs BOOST to make good power... it has a horrible flowing cylinder head... the smaller you go on compressors, usually the less efficient they are at high pressure ratios (boost)

side by side twins are a single stage of compression... if you go smaller on the turbos, they'll be even LESS efficient at higher boost

this isn't about how many total cm of ehaust turbine housing you have... this is about compressor maps and the need for high pressure ratios to make any power.

my guess is you'll be lucky to see 5psi before 3000rpm
 
in my mind two stock turbo's side by side is not worth the build.....just throw a big "S" turbo under it and be done with it.
 
Forrest Nearing said:
I seriously doubt that you have taken a factory turbocharged gasoline vehicle and added a 2nd factory turbo right beside the original one and had it work great

y'all need to learn how to read a compressor map :o
Click to expand...

I never said "factory" turbocharged. Example. 468 bbc callies crank, eagle rods, ross pistons, dart heads. 8.1 compression, marine intake, megasquirt injection. Twin to4b's, homemade headers, went 9 flat in a 2600 lb. monza.

Next, a 455 olds, girdled bottom end, 425 steel crank. Eagle rods, Arais pistons, Aluminum Batten heads, blow through Dominator, Harland Sharp, etc. etc. Also twin to4b's, ran a best of 6.32 in the 1/8th mile before I spun a rod bearing. In a 3300lb Olds Cutlass. That's been 10-12 years ago before I had kids. All runs a National Trails and Pacemaker in Ohio.

Next, a factory turbocharged 83 thunderbird 2.3 4 banger. Ran steady 13 flat in the quarter in high school.

SBC 383 with twins, in a older chevy camaro. Never did get to run it, but probably a 11 sec. very streetable car.


I'm not entirely retarded, I"M NOT bragging about having done xxxxx in xxxxx. I'm not as knowledgable as most on here , but I know what works on gas engines. I understand this is different (big time), HELP ME OUT here. I would like to try a set of parallels on a cummins, surely you can give me some guidence. If it doesn't work I won't hold it against you if it doesn't:Cheer:

thanks,
Mike
 
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