NH-250 Supercharged??

[BillabongKong]

Hey did you guys see the turbo for sale in the classifieds?

 

[Cycletek]

I have turbos, I have two fresh rebuilt ones for my Coach as spares........

 

[hairba11]

so in going back to the original intent of the thread, seems like nobody has ever tried a blower before but it sounds interesting.
the debate of blower v. turbo is as old as the devices.
if you already have the blowers "sitting under a workbench" as you phrased it why not give it a shot?
the absolute worst thing is blowing it up, but if motor swaps are already being discussed might as well blow it up while learning something.

 

[Cycletek]

I find it interesting that you "assume" that I am going to blow it up. You know there are people out in the world that probably have a whole bunch more experience modifying things than perhaps you do. You have no idea what I do and since you all think because you own something your way is the only way to do things. As I have stated a bunch of times in this post, I plan just to add some mid range torque, not make a car crushing monster truck.........I have been building motors for 35 years........I built race vehicles of different type for the last 25 years.....I understand the dynamics that a motor requires and to "win" a race, you must "finish" a race, which usually means not blowing up the motor. I understand the rest of the truck is not necessarily up to to much more HP, so I am going to move the power up slowly and have the necessary monitors to keep the motor happy. I built a Detroit 8v71 w/ Turbo when everyone is afraid of them and how fragile they are, guess what it has 30K on it now in a 30k bus with a 10k Stacker trailer. A smaller motor on a heavier vehicle, the Blowers are spares for the Bus. I am going to use a Vortech supercharger which is a turbo with a belt, it is a lot smaller with less plumbing and less underhood heat, but it doesn't back heat into the motor like a turbo does. I drive this truck everyday so I want it reliable and safe, you know fear comes from the unknown, I am approaching this with decades of knowledge............No Fear Here

 

[m16ty]

I don't think you'll blow it up. I don't think you'll make any more hp over a turbo though.

Build it and lets see some results and you can shut me up.

 

[hairba11]

i don't think it would blow up, and i don't think he's trying to make more power than a turbo, or at least not more peak power.
depending on how it is driven it could provide more boost at lower rpm than you would get from a turbo.
the 1800-2100 rpm power band the NA motor has is only at the top of the rpm range. every upshift drops you out of the sweet spot.
if you could get more power at 1400-1700 rpm the driveability would increase greatly.

 

[350TacoZilla]

nice part of a supercharger is you can size the pulley to get the rpm band you want, if you never plan to exceed 2500 rpm you can size pulleys so supercharger runs out of speed @ 2500. If the supercharger is a pretty good size unit and is made to support a 7L motor @ 6000 rpm then with right pulley it will be more than up to task of supporting 14L @3000rpm. I would try to get the charger to make about 8-10 psi and be building boost just off idle, run out of steam on charger at 2200-2500 and you would have lot more low down torque and when rpms drop on long pulls the charger would be building boost without needing to 'spool' up like turbo so you would never fall below boost.

 

[Cycletek]

350Taco is absolutely correct, I have found with my Detroit and its addition of a Turbo, it gets better boost if I lug the motor a bit making it a little less efficient to build boost earlier. I even changed the gear drive ratio on the blower to try to follow the Turbo output better, so it doesn't become a hindrance in the equation But Detroit's are not too happy being lugged, they like to be cranked up where a Cummins would probably have some issues. Also with a turbo the I have noticed that the altitude and the air moister plays a lot in torque output too. The fuel burn rate also changes the CFM output of the motor which affects the spool time as well, there are a lot of inconsistent variable using the exhaust as a driver for the compressor, plus there is the is the fact that the turbo holds the heat back in the motor raising the EGT. Using the Supercharger I can tune and follow the pressure build all the way up the RPM range with a whole lot better control, plus I can bleed pressure with an adjustable waste gate. I have already sourced a whole bunch of monitoring gauges and sensors to keep and eye on things. I know the stock CFM for the intake and exhaust for my 250 motor so I emailed Vortech my requirements and boost needs which i plan to keep between 8-12 lbs with a max of 20 lbs. and they are making me some v-belt pulleys to match what is on the motor to drive it, it will be sitting on the intake side just behind and below the power steering pump, I have already drawn up a extension shaft with bearings so the blower sits back parallel with the compressor and fuel pump. After I get it all in place I would like to put in an air to water intercooler but run a separate cooling system with a small radiator and electric pump to cool the intake charge, but I will deal with that later. I will keep you posted with my progress and will document it with some pictures once I start.......Have a Merry Christmas!

 

[supermechanic]

Any Progress ?

 

[tobyS]

Electric blower for low, but positive pressure. A 1 hp Emerson permanent magnet 24vdc and a reasonable vacuum fan, single or multi stage, could put twice or three times the oxygen mass into the engine over suction (negative pressure), I believe. Figure the mass of the air at 20" negative and the mass at one pound or so positive, keeping in mind that air is 78% nitrogen and 21% O, and you may have what you are after Cycletek.

 

[patracy]

Electric blower for low, but positive pressure. A 1 hp Emerson permanent magnet 24vdc and a reasonable vacuum fan, single or multi stage, could put twice or three times the oxygen mass into the engine over suction (negative pressure), I believe. Figure the mass of the air at 20" negative and the mass at one pound or so positive, keeping in mind that air is 78% nitrogen and 21% O, and you may have what you are after Cycletek.

I'm just glad that hotrod finally laid the electric blower myth to rest.

5 gas powered leaf blowers didn't help...
http://www.youtube.com/watch?v=U81_0waqEWA

 

[tobyS]

LOL...I had a Pontiac Sunbird with the 305. Purchased brand new (mistake). It had something like 4.11 gears and no top end but fast between two stop signs. I went to school rather than put money into it, trading for a older (70) Porsche 914 that would run 95 all day long and get 35 mpg vs the Sunbird 10. It was a lot more comfortable too as the tunnel in the Sunbird left about 12" width for ones feet. Re the video, I wish they had a pressure gauge mounted to see what boost it ran, first with the two and then more.

I thought cycletek just wanted a modest, get a little more response out of it, gain. Wonder if anyone here has balanced or did valve work on a 250 to get higher r's. I have a couple of friends that build valve systems for the Cummins tractor pullers and will see what they may know about a 250.

 

[patracy]

The NHC's weakness seems to be more of the bottom end. Every failure I've seen is a rod, piston, or liner failure.

 

[tobyS]

Clearly I'm out of my league with the more race and pulling experience here. A second read of the thread has cleared up some of my thoughts on what the desired outcome is. I thought it was just modest torque gain in a comfortable (low) rpm range... but racing or pulling may be the goal. As rpm is a function of hp...seems one should be looking at what higher rpm will do with the massive volume of air being discussed.

Your right patracy, it's a bottom end failure that is likely with that loooong stroke. I'd like to see a crank, rod and piston balance before making a LOT more air the issue. Personally I wouldn't want the cost of that much premium oil. My suggestion (doubling the amount of O in the cylinder, not volume moving through it) was entirely for a modest low end gain of torque, not a racing engine that achieves hp by high rpm.

 

[jedawson1]

Well now that debate is over I hope you make it to experimenting. I am hopeful that this proves successful. Wouldn't mind making this mod on mine if it works for you.
Keep us posted, and don't pay attention to the nay sayers. You have the resources and know how to put this together, and to replace the motor if something goes wrong. Let's get r done.

 

[dburt]

So what is going on with this build?? I just went thru the entire thread, and ended up at this long pause here- the suspense is killing me. I've had blowers in cars, and turbo's in trucks and always wondered if a blower would work in a diesel. Now I hope we all get to see what happens- and it looks like it's finally going to happen! Please hurry tho- I've waited many years for such a test as this. And I like your thinking out of the box- that's what makes life interesting.
My grandma used to tell me "just because you can doesn't mean you should" but if you have the $$, experience, tools and a shop to work in- well, why not?

 

[Jayco36REQS]

Sorry guys .. all mods on hold for awhile.. Been dealing with dual herniated disc's in my neck all summer, and having surgery next week. I'll be out of action for another 4-6 months. So maybe this will be a spring project next year. Cheers.

 

[dburt]

Bummer Jayco- hope you heal up fast!