ak diesel driver
6.5 driver
My understanding is that twins will give you more volume without necessarily more pressure. Compounds while upping volume will really up the pressure.
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My Twin Turbo 6.5 (GM4 & GM8)
- Thread starter DZZ71
- Start date
My understanding is that twins will give you more volume without necessarily more pressure. Compounds while upping volume will really up the pressure.
Woody35
Active Member
more details please! but this is one sweet build
great white
Well-Known Member
Bingo.
It's more about mass than it is about pressure.
Essentially, he's created one 4 cyl feed by a gm8 and one feed by a gm4 on a common crank. On the face of it, it's like doubling the mass flow as he's halved the displacement for the same given turbo. Of course, it's still limited by the ds4 fueling capacity to actually use that extra mass......
But, I think by dividing the plenum he's found a way to "cheat" the mass and pressure relationship for this particular design. That's just off the top of my head though...
Power pulses acting on the crank is another story....still thinking about that one....would have to see the compressor maps for each gm* turbo to know....but you're back into the ds4 limits.
Probably running cooler on one side than the other. Then there's the issue of one side of the plenum seeing one boost level, the other side another. Same with IAT. I suppose you could just run the DS4/PCM off one side and assume the other is the same. I don't see any other way to get the PCM to see both signals without confusing it....
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randomid25
Rattle-Trap Cap'n
Curious as to what you're gonna do to fuel that setup. I'd be surprised if a ds4 could take advantage of the airflow of twins. Nice fab work.
DZZ71
"Living The 6.5 Dream"
The precups arnt overly big, i wasent sure how much was to much. They were ground with a die grinder. My pistions had 70 tho shaved off. I finnaly got the injection pump figured out. The timing was to de-vanced to even take the re-learn with out dieing. Also the harness had a few defects which was giving me the 17 and 18 code. So its all properly timed now and it sure runs smooth. Best running 6.5 i have owned yet. The lower compression hasent giving me any problems at all yet. even for cold starts. I will post results later this week as i break in the engine to actually lay the hammer down.
3500GMC
What T F, over
CNC die grinder. :thumbsup:
625fireman
I have injecter-itis
I was wondering about this setup my self. I had it built prolly a dozen times in my head but never had the time, money etc to do it. VERY nicely done. The only thing better I can see on this would be Dual A-Teams :hihi:
DZZ71
"Living The 6.5 Dream"
Next one is gonna be dual HX35s intercooled for my white 1995.Goal is 300rwhp. I just don't know if I should build off my 141 599 or 506.
Matt Bachand
Depends on the 6.5
You may notice slight lag with this setup, but at midrange to upper range RPM I would think you'll be within effecient ranges of both turbos for a real sweet spot. Should pull strong once the lag is cleared.
DieselSlug
Well-Known Member
Nice fab skills! When i get to my installing of the HX im gonna need help with the 4'' d/p!
NVW
Well-Known Member
Looks good, next video slow down while laying on your back on the frozen ground so we can have a better look
Veg_Out
Walking J Designs
This group of gear heads never ceases to amaze me. Well done!
agreed with others, this is very well built and clean. I knew someone would mess with the factory cast manifolds enough to find the right twin setup. great placement of the hot pressure side/turbos, and smart working with iron to remove the chance of cracks. like how you divided the cold sides too.
buddy
Active Member
The DS4 IP can output more fuel than most people know, so I think it can easily take advantage of two GM turbos. I dont think there is much difference in a GM4 vs GM8 to make an imbalance you would notice.
I personally would go for a compound setup, but there is merit to both options, and the dual is easier to implement in short order without a lot of mess.
I personally would go for a compound setup, but there is merit to both options, and the dual is easier to implement in short order without a lot of mess.
turbonator
Member
bump.... this is the forum where this thread belongs..... innovation and experimentation..... to many know-it-alls on the other site to except something like this...
buddy
Active Member
I just realized you have the square precups, and even after your porting of sorts it is still smaller than the diamonds. Getting some diamonds, or porting yours further would actually help at really high fuel rates.
DZZ71
"Living The 6.5 Dream"
Is that right? How much more would be safe buddy? I wasent sure how big i could go not seeing anyone elses. Does anyone here have any photos on custom precups?
buddy
Active Member
Here are the several stock type, compliments of MGW, you can see the diamonds are bigger than the squares, but some have ported out larger than diamonds. I cannot recommend much bigger than the diamonds, as I dont yet have mine installed, and I still have the smaller square or dot cups in mine.
ak diesel driver
6.5 driver
Hank58 custom machined his precups and liked the results. I believe he started with the diamond ones. There's a thread on it here somewhere.