Supercharged 7.3

[2000wa250]

V8 with a lot more displacement than a 5.9 i6 ... I just think what were all saying is in our opinions it would be more effective to run it the other way

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[Hotrodtractor]

Well I highly doubt the turbo will pull vacuum as a 122 Cubic inch blower spinning thousands of rpms will be pushing air into its inlet. If that were to occur like i said there is several options. There has been several Cummins setups with the blower feeding the turbo and they worked just fine.

The article you reference as a source even mentions that it is a possibility. Just saying.

We do know about these setups. I have seen a couple of them in person. There is a mod here that had one on his 6.0. There is a a member that I haven't seen in around in a while that has one on his 7.3. Both of those are setups were Procharger setups.

 

[jimdawg185]

The possibility is there for a vacuum situation. But, your nearly there, you mine as well finish it and take the data you get and improve here on out. I like different projects like this. Keep it up bro.

 

[superpsd]

V8 with a lot more displacement than a 5.9 i6 ... I just think what were all saying is in our opinions it would be more effective to run it the other way

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They were running a m112 I have a m122 below is a reference picture of a comparison. Also they have ran Eaton m90s on 5.9s which is a smaller 90 cubic inch blower A couple of guys have also ran m90s on 7.3 idi motors which had no problem developing boost. once this is up and running the boost/vaccum gauge I have will tell me good or bad.

 

[superpsd]

The article you reference as a source even mentions that it is a possibility. Just saying.

We do know about these setups. I have seen a couple of them in person. There is a mod here that had one on his 6.0. There is a a member that I haven't seen in around in a while that has one on his 7.3. Both of those are setups were Procharger setups.

That is a centrifugal charger not a positive displacement roots blower. Roots and twin screw chargers make instant boost centrifugals do not.

 

[2000wa250]

I hope it works out for you. Sure seems like a hell of a lot of work with not much to be gained.

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[Hotrodtractor]

That is a centrifugal charger not a positive displacement roots blower. Roots and twin screw chargers make instant boost centrifugals do not.

I know the difference between the two. Please install gauges when you get yours finished and you will see exactly what we are talking about.

FWIW - I love new and different projects - I like the idea of a blower on a diesel. I just want to help you be more successful in round one - but you are close enough that you will see what we are telling you.

 

[superpsd]

I understand. Vacuum will occur when the turbo is pulling more than the blower can push. This can happen but right now I can only guess on that part. If it does happen there are options; a bypasss, a larger Whipple, or pulley the Eaton for an increase in airflow. The vacuum scenario would likely be in the higher range but could happen under heavy load. The key will be to push more air than the compressor can ingest preventing the vacuum scenario from happening. Majority of my driving daily is flat ground to work and around town and I rarely rev the 7.3 over 2-2200 ish which will likely be a happy plane for a roots blower hence why I am going with one. The other reason is to greatly minimize smoke. I don't need 500hp I am happy with 300. Not a race truck i want drivability.

 

[Charles]

If a blower was the key to a smoke free, efficient 300hp diesel then you would see it happening on cummins, cat, deere, yanmar, international and the rest daily.


When I'm pissing exhaust energy out the tailpipe to the tune of say 30% of my total fuel BTU, I'm not at all interested in using my crankshaft to pressurize my intake air when a turbine can snag some of that waste energy that's already leaving. Which is exactly why the above mentioned companies don't do it.

I think the most successful turbo/blower engine I know of in the realm we're talking about here was a pair of chargers ahead of a blower on a duramax. Every single time a blower was put ahead of a turbo dyno sheets, track times nor anything else ever showed anything unless I missed it, which I may have.

If the blower goes second, the engine displacement simply becomes that of the blower. The turbo can then jump on boost like nobody's business, and a centrifugal can't get in the way like a positive displacement unit.

What OEM runs blower into turbo? Serious question.

 

[Charles]

I googled turbocharger and supercharger and the hellion kit for the GT500 came up right on top. They blow two chargers right through the supercharger. No mention of the rotors or blower giving any damns at 1200hp...

I think that talk is mostly just supercharger guys being supercharger guys... The blower doesn't care what you feed it, only what the PR is, just like everything else. I would run interstage cooling to keep it cool and rock out.

 

[Charles]

I started thinking about this again...

If an M112 is a 112CI/rev unit, then it would have to spin over 12,000rpm just to keep from forming a vacuum ahead of a stock charger at full song. Over 14,000rpm to stay even with a 38R at full song. That's not to make decent boost, but just to keep from choking the turbo.

Also, on some quick research, it appears flex has to do with rpm and rotor length. So in fact, a smaller unit (with shorter rotors) would be stronger second stage. And second stage it only has to stay above ~300 or so CFM (the engine displacement), not the 7 to 900+ of even a small 7.3 charger.

The engine the blower came off of (5.4???) would only move 475cfm at 5000rpm even if it acheived 100% VE! And a stock 7.3 turbo moves another 300 or so CFM!

Point being, I would not under-estimate the possibility of the blower turning into a coffee stirring straw ahead of even a stock charger. A 122CI blower isn't in the realm of a turbo.

 

[superpsd]

Well there have been quite a few setups where the turbo was first and quite a few where the blower was. Both setups can work. And some use a bypass once the turbo comes to life so the blower is not a restriction. The twin turbo blown duramax you talk of now just has a whipple and spray and no turbo. I made some progress got stuck for a few days trying to figure out how is was going to build the discharge elbow and looking thru my pile of parts found a Detroit 453 blower inlet that's going to work.

 

[Charles]

Well there have been quite a few setups where the turbo was first and quite a few where the blower was. Both setups can work. And some use a bypass once the turbo comes to life so the blower is not a restriction. The twin turbo blown duramax you talk of now just has a whipple and spray and no turbo. I made some progress got stuck for a few days trying to figure out how is was going to build the discharge elbow and looking thru my pile of parts found a Detroit 453 blower inlet that's going to work.

I would place the ducting and blower so that I wouldn't have to move much to let the stock charger feed through the intercooler then from intercooler to blower, then blower to manifold. Place a couple water injection nozzles in between blower and manifold and let the big dog eat. Would jump on boost. But still move no more air, but PR would be better, so more density maybe. Upping the turbo size would be the next step with the blower handling low rpm duty.

If you can't get up on a stock charger without help I'd look at something other than the induction system anyway.

The problem with smoke free 300hp IMO is the limit of the stock charger to make the 300hp without smoke, not for the stock charger to come up off idle making power. A blower of the size mentioned is barely capable of supplying the air the stock charger can, and with less efficiency, so I don't see the benefit.

Now, letting the blower pick the truck up off the bottom, and having a larger turbo feed in up top I could see. That would augment the need for O2 to achieve 300hp without smoke.

Lastly, the injection nozzle size probably has more to do with this goal than anything in this thread.

Regardless, if you do get something driving around, it would provide some interesting tests.


On Edit:

The blower setups I've read about before with blower ahead of turbo have a knack of viewing a dyno like superman does Kryptonite. Oh it drives so awesome, blows the tires off, so badass.....

Yet anybody that drives or rides that's familiar with similarly turbo'd engines says meh.... Noses over... snappy and that's it. A decent compound setup will send your rods into next week at 1500rpm if low rpm power is your goal anyway. I've always had to pull power down low for engine longevity. Even my 550 with a single 38R has reduced fueling down low to keep things calm. In fact, it also has the larger 1.15 turbine housing. The last thing I need is more help down low. And it's a tow truck. Coincidentally it makes around 300hp. If I wanted to turn the map based fueling on it could be smoke free, but I like the simplicity of flat maps and as little trimming as possible, so it huffs smoke until it lights.

 

[superpsd]

It's not a m112 it's a m122 (2.1L) and a maximum blower recommended rated speed of 14,000 rpm.

 

[Charles]

It's not a m112 it's a m122 (2.1L) and a maximum blower recommended rated speed of 14,000 rpm.

If you ran it to 14,000rpm with flames blowing out the discharge it would be 900CFM and change?

A stock superduty charger is close to 800 and a 38R is over 900. Best case I see it being a really inefficient and expensive tornado, vortex air spinny thing hanging out in the intake duct that helps spit rods down low.

Second stage I see limitless potential. But I feel like I'm F'ing up your thread a little, so just keep on keepin on because it will be cool to see what happens. Maybe it will break the trend.

Btw, you started this thread by talking about an M112 you were using.

On Edit:

My mistake, it wasn't until post #12. M122 it is regardless.

 

[TyCorr]

It's not a m112 it's a m122 (2.1L) and a maximum blower recommended rated speed of 14,000 rpm.

Right and at 14,000 rpm it will be barely keeping up with a turbo much less "feeding" it.

 

[superpsd]

Another intesting thing I found was maximum flow rates . Garrett tp38=767 cfm Eaton M122 865 cfm. They also have a direct whipple replacement for the M122 that is a 4.0lL unit.

 

[superpsd]

Also another note. There are whipple upgrades for the GT500s M122 that range from 2.6 to 4.5L of displacement. A 2.6 flows 1400 cfm and a 4.0 can flow 2518cfm so there's many choices to cure any lack in airflow. The 4.0 also has a maximum speed of 18,000 rpm.

 

[2000wa250]

I don't think you quite grasp the depth of knowledge that Charles has...he probably has forgotten more about the 7.3 that you will ever know. That being said..

Your plan with the current charger you have will, for lack of a better term, turn the charger into a really expensive air intake heater. If you don't cool between the blower and the turbo...well ****...hope you have an egt gauge...

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[Charles]

Another intesting thing I found was maximum flow rates . Garrett tp38=767 cfm Eaton M122 865 cfm. They also have a direct whipple replacement for the M122 that is a 4.0lL unit.

My calcs from the hip were ~780 for the tp38 and ~907 for the M122.

Thing is, a bigger supercharger never fixes the fact that it will make the most boost when you're using the least power, and make the least boost when you're making the most power.... ass backward. That's because a fixed displacement unit is ahead of a dynamic unit.

All you would need do is place the unit you have (or a smaller one even) directly on the engine and let a turbo feed it. Then the blower size and pulley can be figured directly, exactly as designed, and the turbo can pump up the ambient air density, again, exactly as it was designed. As long as you didn't get the turbo too fiesty or the blower output too low, creating a pressure drop post blower, then the turbo boost wouldn't try to shove the rotors down the intake manifold.

The blower would take the 7.3 from 300ish CFM up to 5 to 600ish CFM and still be efficient. This would let you run a large single charger to bring some ice cold air to the party, and it would get up on that charger fast because the charger would only see the blower displacement, making it think it was on a 14 or so Liter engine! Talk about getting on top of a charger...

Think 88mm charger or so.

Here's the kicker.... it would still spool a bit slower than a compound setup with the same pressure ratios per stage because the blower can't come up on boost any faster than it's pulley, whereas the turbo can jump on boost as soon as exhaust drive permits. And it would consume more power, putting less to the ground. And it would make the boost it made less efficiently as well.