Compound turbo build and other updates

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I think first and foremost you need more timing. That late fueling is creating higher drive pressure and therefore boost but it's not fully utilized boost. This is sort of like when custom tuning guys add late fueling on the bottom end to help spool up. It's great for spooling but not for creating big horsepower.

I'll bet if you bump the timing to 25* or so, you'll see a significant drop in EGT, drive pressure, and slower spooling but you'll get a nice bump in horsepower. Then, you'll need to increase the fueling to take full advantage of that big 88mm turbo.

I see no reason why that twin setup can't support 850 HP.
 
Made an adjustable spring gate for the 351 today. Hopefully it works and I can tune this thing in better. ImageUploadedByTapatalk1356918770.569039.jpg


Sent from my iPhone 4s
 
Did some more runs with the gate tighter. Boost went up a tad, primary was still around 30.
Drive seemed to go up faster, over 3000 rpm it was swinging past 80 fast! Egt maybe a bit cooler until drive went up then it pegged over pretty quick like usual. Guess I'll bump the timing next but I'm kinda worried the headgasket ain't gonna like it.

Side note, has anyone had problems with the he351 comp housing rotating on its own? Obviously when I reclocked it I had to remove the little locating pin so now all thats holding it is the big snap ring. But I think the intercooler pipe is pushing on it or something when the engine torques over cause it keeps on reclocking itself where I dont want itLOL.
 
Took a little vid for the heck of it, WOT in overdive.
[ame="http://www.youtube.com/watch?v=1YvLVbwT3mE"]Twin turbo 12v - YouTube[/ame]

Boost hit 62, drive was about 80 and climbing. Needs more power haha. Gonna bump the timing when I get a chance.
 
i did not had problems with housing rotating but if you did not get the snap ring seated correctly i could see it rotating. it could also create a boost leak from the cover not sealing.
 
jlbayes said:
i did not had problems with housing rotating but if you did not get the snap ring seated correctly i could see it rotating. it could also create a boost leak from the cover not sealing.
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As far as I know the snap ring is seated. Unless its supposed to only go one way? I just made a brace to keep it from moving. I should check for boost leaks there cause the housing didn't seem like a very tight fit when I put it together.


Sent from my iPhone 4s
 
the snap ring has a taper, make sure you did not install it upside down by chance. i've had to clean out the groove on a couple of housings because of corrosion.
 
PM I got from a member.

mq105 said:
I ran a 351/S475 for years and while it's a great DD set up, the 351 can only handle so much - on the exhaust and comp side. You have a good amount of fuel also.
You're aware of the DP issues; I see you're monitoring that. But, the primary's air can get restricted (and hot) by the 351 comp. That contributes to the high EGT and you'll get high primary boost psi because the 351 can't move the volume the 488 pushes.
The answer is usually to drive the 351 harder. But, to do that you must keep the gate tighter/closed longer, and then you increase DP, EGTs...
Also consider that it's winter. What will summer temps do to EGTs?
Of course, check all the basics (leaks, AFC, timing, etc.) but in my opinion you'll have to make a choice. Either you can ease off slightly on the fuel (smaller injectors), or go to an S36X secondary.
For DD and towing, the smaller injectors would get you a snappy, torquey, clean-running truck in the 600hp range with acceptable EGT. Revs 3k max.
If you're a peak power guy and like to turn rpm, the S300 (like a 63/68) would be the way to go.


Good luck,

MQ
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Makes quite a bit of sense to me. I'm definitely not giving up on the 351 yet though, might try an e-gate. But I think a big part of the problem is the tiny turbine, not the wastgate.

On a side note, I found this while surfing around. Looks interesting. And t would drop in without changing piping.
AGP BW Cummins 5.9 Bolt-On Turbo Upgrade - AGP Turbochargers, Inc. Store
 
12vCumminsFTW said:
PM I got from a member.



Makes quite a bit of sense to me. I'm definitely not giving up on the 351 yet though, might try an e-gate. But I think a big part of the problem is the tiny turbine, not the wastgate.

On a side note, I found this while surfing around. Looks interesting. And t would drop in without changing piping.
AGP BW Cummins 5.9 Bolt-On Turbo Upgrade - AGP Turbochargers, Inc. Store
Click to expand...

why not machine the turbine hsg to accept this?

BAE Turbo Systems Inc. - 70mm x 64mm


and if need be you can step up the compressor also:

BAE Turbo Systems Inc. - 62mm x 86mm
 
I and highly considering the bae upgraded wheels for mine. I think its the main reason my primary boost is as low as it is.
 
I'm trying to decide if an e-gate would help me out or not. But i think the small turbine is part of the problem.

BTW, I did some runs tonight and drive hit 90 psi at 60 psi boost and egt hit 1900 at 100mph. The primary was 30-35 but its nowhere as strong as it should be. I think its partly cause the 351 isn't spinning hard enough but if I tighten the gate more won't drive go up even more?

Hopefully I have time this weekend to bump the timing to 25ish and fool with the gate and see what happens.
 
I really like the sound of the agp turbo though. The 68mm turbine would flow way better and with the slightly bigger exh. housing it probably wouldn't need an e-gate. But it would spool slower for sure.
 
Looky what showed up today! agp 63/68/12 with 360 degree thrust bearing. gonna do some porting on it and maybe drill the gate hole out if possible.
IMG_0158.jpg
 
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