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Need help with supercharging a 6.2

So with the 10 rib, did you check how high the boost went?
You might not have a leak but maybe at a certain pressure the SC was so stiff the belt was slipping and not building as much anymore.
Try it before you change anything else?

Orange Bomber said:
So after a crazy couple weeks at work I finally got to working on my truck. New ten rib belt, didn't change boost levels but there's no dust which is good. Built a pressure tester, nothing leaked, I kinda was hoping I had some leak that would explain it all but nothing. Got around to calling a local machine shop and found out that a custom pulley would cost me around 450 dollars to get made. So I did some looking and figure that a 1.5 pulley would about as small as I could go because it'd max out the SC at 2500rpm and be in its efficiency range at 2000rpm which is perfect.
My worry is a pulley that small even though its ten rib wide, how bad is that going to slip because there isn't a whole lotta surface contact going on? I also can't decide if 450 bucks is worth it to get something that is a toss up if its actually going to work. I've also been looking into turbo set ups and for a little more than what I'd pay for that one pulley, I think I could get a decent set up. What do you guys think?
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I haven't decided if I wanna sell the SC, I'm toying with find something else a little more spacious to throw it on. None of my friends like to ride three deep with me.:haha:I also want to check with lysholm and see how much they want for a manifold and their SC just for fun.

I think Turboing is going to be the way to go though but I took a peek under my truck today and routing the exhaust is going to be a nightmare.
I wanna do some more research on different turbos because I may have a pretty good deal on an HX-35, I've heard they do pretty good.
 
Orange Bomber said:
With the 10 rib The most I've seen is 6# but that's reving it pretty high.
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revving it in neutral is not the same.
Drive it around and see what you are getting.
If you are getting 6lbs, it's not that bad.
You can also tell from the seat of the pants feeling if it's good enough for what you have put in it so far.
 
Driving it around the highest I've seen is 5# but again that's at like 3000rpm and at 2000rpm I'm still at 2#. Seat of the pants feel is better than it was but still not where I want it to be. 4th gear takes a bit to get going unless I shift at a higher point and 5th is kinda useless.
 
Orange Bomber said:
Driving it around the highest I've seen is 5# but again that's at like 3000rpm and at 2000rpm I'm still at 2#. Seat of the pants feel is better than it was but still not where I want it to be. 4th gear takes a bit to get going unless I shift at a higher point and 5th is kinda useless.
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And that driving test was after the 10 rib?
 
Well I don't remember if the SC is new or used, but what if the SC is not holding pressure?
The numbers you were coming up with in the beginning where supposed to be much higher, did you do the math wrong or is the pressure going somewhere?
 
I pressurized my system and nothing leaked so I don't think its escaping anywhere. And as for the proposed numbers I was told those by the sales rep and when I talked to the tech dept they said that to get the 8# I was looking for I had to spin my SC twice as fast as I am now. I did find a compressor map for my SC but have no idea how to read it if that'd help at all?
 
So I emailed Marine diesel in Australia about there SC set ups they use, they sent me to Performance diesel in Texas who is a dealer for them. After talking to PDI, that Bullet diesel SC set up is looking pretty well priced. Just the Marine diesel custom manifold is 1200 bucks. The SC body was between 4-5 depending on which body I wanted, that's just insane to me. So needless to say that's not going to happen.

After a bunch of looking and figuring that none of the off the shelf turbo set ups wont fit my truck very easily. Another thought I had which started as a joke, then thinking about it I wondered if it'd really work. Could mounting a turbo onto my supercharger, so that the SC would spin the exhaust turbine insted of using exhaust gases spin the turbo enough to make any boost? Then I'd route both the down pipe and the pressure side of the turbo to my intake to get the boost from both chargers. I know its a long shot that it'd actually work but I figured I'd see what you guys thought.
 
I think you should go with your first impression. ;)

Pumping losses and other compounded parasitic losses are going to kill that idea beyond dead. The only way that could ever work is if the 1st law of Thermal Dynamics were suspended, and then we would be on our way to perpetual motion. Also, the continued expansion of exhaust gasses is a big part of what gets a turbo up to speed, and all your feeding it is some air heated by initial (low really) compression. No where near what you need.

Don't recall what you are putting this in, but I suspect that working out the details of a turbo setup would have been far cheaper and done long ago. Is it really that bad? Yeah, it'll clutter the engine bay and make things hard to work on, but look under the hood of my 500 hp DMax. :D There's a very good reason why it's so popular (complete dominance really) on Diesels.
 
Yes theres some that compound a centrifugal supercharger and turbo..... or turbos. But they are not set up like you describe.
 
Subscribed. This is an interesting read. Just curious, did you drive the truck without the sc set up? The 6.2 is really slow (torquey but slow). With my 4 speed people behind me at traffic lights get very angry as I calmly accelerate through the gears and smile as I listen to their barely audible horns squeak past the rumble of my exhaust. If I had any seat of the pants feeling in my truck at all I would be very impressed. I realize your boost numbers are not what you are looking for, but I'm wondering what your actual performance gains are over stock.
 
Baddog, I'm not really familiar with the laws of thermodynamics but I'll take your word for it, I was just curious if it would work though. The reason I didn't go with a turbo to begin with is if I use a stock 6.5 manifold the down pipe will be in the middle of my heater, and the banks kits crossover pipe will hit my crossover steering. Not to mention the nightmare of a time I would have routing my exhaust back through my truck. I had the supercharger available to me and I wanted to try something I hadn't seen before. Also, banks just used a roots style supercharger on their d-max to make 1500hp. http://www.8-lug.com/events/1202_8l_trucks_of_sema_2011/photo_15.html So sick!

Demon, I just read the other night about people having a SC feed into the intake side of a turbo to help spool it faster and eliminate turbo lag. Just kinda curious if my way would have worked in a similar fashion or not.

Richcz28, Yea I drove it for about 6 months without the supercharger on, it wasn't the fastest thing out there but it was faster than my uncles stock 88 6.2 with an automatic. 1-3 gears always were pretty quick, its just from 3rd to 4th that was a bit slow to pick up speed. So I just shifted a little later than normal from 3-4 which helps that problem.

Seat of the pants performance is better than it was stock. stock form I was getting about 14-15 driving calmly, now I get the same with my foot in it all the time, so Mpg gained a little as well. I also noticed just turning up my injection pump without any boost help a bunch in performance. I had it a 1/4 turn with out the supercharger and it was pretty fun, and egts were still pretty manageable.
 
Damn that thing is bad ass! Looks like a gas motor!

1202-8l-18+trucks-of-sema-2011+banks-power-supercharged-duramax-v-8-engine.jpg
 
I know right! They said 1500hp and 1500lb at 6500rpm. That crank pulley looks massive. I wish I could get mine to spin faster.
 
Having an easy/cheap access can certainly shift priorities, though sometimes in a generally up hill direction. ;)

The "first law" is basically the one that says you can't get out more than you put in. It's the one every single "perpetual motion" advocate overlooks. So in this case, it just tells us that using a SC to drive a TC isn't going to produce more boost than the SC produced.

And yes, I've seen where the combo is used to help eliminate lag. But that's an even bigger mess than just running the TC normally, so I don't think that helps. You may spend a few HP to get it spooling quicker, then let the exhaust take over, but it's not an end in itself.

And you mentioned the bottom pulley in that picture. When you go as small as you can on the driven side, going larger on the drive side is still (maybe) an option. Too bad you don't have a Roots/Spool/Positive type SC, they don't require such high rpms.
 
So if I put 2lbs into the TC Via the SC I'd get 2lbs outta the TC for a total of 4lbs? Or would the friction loss of the SC boost blowing through the TC be to much to leave any boost for the engine?
Yea I wish I could do a roots style, but trying to fab up a manifold to support one doesn't look so appealing. I thought about going bigger on the drive pulley but to get where I want to be I'd be looking at a 15" crank pulley, I defiantly don't have room for that. I'm looking into getting a 6.5 manifold and modifying it to move the turbo forward more or if I could fit twins somehow.
 
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