pros and cons on running a supercharger on a off road rig.i have weiand 144 ci sitting in my tool box and im thinking of putting it on my jimmy.
CK5
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superchargers
- Thread starter sledheadak
- Start date
Pro: Torque. Now! 
Con: Gotta run premium fuel. Always.
You will break more parts, because you won't be able to keep your foot out of it.
Con: Gotta run premium fuel. Always.
You will break more parts, because you won't be able to keep your foot out of it.
tiger9297
1/2 ton status
I had thought about going with a turbo/super charger on my truck for towing, but the cost, heat, and reliability issues kinda keep me away from it. Towing a camper in MS in August when it's 98* and 98% humidity is not the time to add heat to an engine. I haven't ruled it out but just some of my concerns.
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There's no way it will work. I'm feeling nice, so if you ship it to me, I will scrap it for you. 
I dream of a blown small block with different sized pulleys so I can run cheaper gas on long trips and race gas for big fun. As tiger said, anytime you add a lot of power, you have to add more cooling.
How about a setup like Mad Max had where he could turn the blower on and off. I'm not really sure how that worked...
There are lots of posts on what it takes to run a Supercharger.
I dream of a blown small block with different sized pulleys so I can run cheaper gas on long trips and race gas for big fun. As tiger said, anytime you add a lot of power, you have to add more cooling.
How about a setup like Mad Max had where he could turn the blower on and off. I'm not really sure how that worked...
There are lots of posts on what it takes to run a Supercharger.
sled_dog
1 ton status
Blue85 said:
That didn't work it was fake. Cool idea but in reality it is pointless. Your carbs or injection hat would have to be sucked through the blower(HUGE restriction) and for a good deal of boost you'd have to run low compression and it would run like crap without the blower.
I wouldn't run a Blower on a trail rig for one reason, HEAT. Those things get toasty. I don't mean they raise the engine temp(do combustion temp since the intake air charge is hotter), but the blower itself will get hot. Especially at constant low speeds and high RPM blasts. An intercooled centrifugal with a CO2 system blowing on the intercooler is about all I'd personally run on the trail. They do sell intercooler setups for roots blowers but they aren't cheap, easy, small, and I doubt they exist for the 144. Now you could throw a 50 shot of nitrous at it from time to time to cool down the intake charge
Also, to really make power you need to build a motor for a blower. Sure you can bolt one on and gain power, but to really run well you should build a motor to match the blower. So if you want to do that, add the cost of a motor. I'd keep the blower but put it on some street motor at some point.
the plan is next winter to build a 383 set up for a blower.the current engine is a 305 so i know it will die soon even tho it only has 75 on it.was wondering about peoples experiance with running then off road and any problems they might of had doing it.i have the boost retarder for the igniton already and matching msd ignition.thanks
BustedTrojan
Registered Member
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Wastegate
You should be able to put a waste gate on it and control your boost in the cab.
You should be able to put a waste gate on it and control your boost in the cab.
A 383 isn't the best candidate for a blower. 
Unless you get custom pistons, or heads with huge chambers, the static compression ratio is around 9.3:1 or higher, depending on the heads. Mine has a comp ratio of right at 9.8:1, even with Keith Black dished pistons, because of the small chamber of the 'vette heads. (58 cc??) 
Unless you get custom pistons, or heads with huge chambers, the static compression ratio is around 9.3:1 or higher, depending on the heads. Mine has a comp ratio of right at 9.8:1, even with Keith Black dished pistons, because of the small chamber of the 'vette heads. (58 cc??)
That wasn't real?sled_dog said:
My dreams are crushed 
It seems like with a centrifugal blower you could run a couple of butterfly valves to select whether the air comes through the supercharger or direct. This would happen simultaneous with the disengaging the clutch on the blower. With about 8:1 compression it would run N/A or forced, although not ideala for either. In the movie they made it look like he turned it off to save on gas. Obviously if it was a standard roots configuration stopping rotation of the supercharger would drop the MPG a lot and make the car a total dog.
I have a similar blower (B&M) on a 350 crate motor waiting to go in my '75. I bought a MSD ignition that reduces the timing as the boost comes up to prevent detonation so ya don't worry about that. Or another way is to run water injection. By the way, the MSD ignition really helped with bottom end power and fuel economy on my '75 daily driver! It cranks and idles better too!
trailblazr81
1/2 ton status
It would be fun if you built a motor for it.. with lower compression, and beef up the cooling. I would be worried about the heat if doing slow moving stuff off road. Just be careful. I saw a Guy with a Blown motor flying through high water and sucked it in to the motor. Pretty much ruined his day quick!! 
He thought he was a Bad-AZZ with his Blown big block, standing on the stupid pedal. I just hopped in my little 383 powered rig and cruised on outta there!!
He thought he was a Bad-AZZ with his Blown big block, standing on the stupid pedal. I just hopped in my little 383 powered rig and cruised on outta there!!
tiger9297
1/2 ton status
Blue85 said:That wasn't real?
It seems like with a centrifugal blower you could run a couple of butterfly valves to select whether the air comes through the supercharger or direct. This would happen simultaneous with the disengaging the clutch on the blower. With about 8:1 compression it would run N/A or forced, although not ideala for either. In the movie they made it look like he turned it off to save on gas. Obviously if it was a standard roots configuration stopping rotation of the supercharger would drop the MPG a lot and make the car a total dog.
On piston engine airplanes that have turbo chargers they use waste gates to control airflow through the turbo. That way it can be "off" when on the ground taxiing, but will be "on" when airborne. These engines are aircooled so heat is a major issue when they are on the ground and operating at slow speeds.
wasted wages
1 ton status
same thing could happen with a naturally aspirated motor,,,,,
Pro's
I run a 6-71 and 2 750 holley's on my K5 on a big block and love it,,tons of torque and HP from idle to redline. just make sure the rest of the driveline is up to the extra stress. The engine is a GM 454 HO crate motor with no mods.
I have been in mud pits with the engine held at 4500 RPM for 3-4 minutes at a time throwin' 20 ft roostertails off all 4 wheels!!!!For mud it's great,,,
Con's
Trail running sucks with a blower,The instant torque and HP is not your friend when your trying to finess a light throttle to bump up over a tight spot.
I have gotten into more than one scarry spot due to this,,also inclines and side hills with 2 -750 holley's is no fun,,fuel slosh into the carbs at the top of a 30-40 ft incline just before the top and flooding the engine is no picnic,,,
My next investment will be to install electronic fuel injection on top of the blower,about a 4.5K price tag,,so as you can see playing with a blown big block can get real costly real quick,,,and that doesn't even begin to cover the many other things I have done ( trans upgrades,cooling system upgrades,fuel system upgrades )
BIG HP = BIG $$$$
how much power can you afford????
For some reason I am recalling a car mag said that right after mad max came out everyone wanted a way to turn the super charger on and off and they had come up with a way to do it, maybe using something like an air conditioner compressor pulley where you could disengage the clutch and then engage it or something?
I ran some searches and the actual mad max stuff is everywhere and I can't find anything resembling what I am thinking I read 10 or 15 years ago.
However, as already mentioned an engine made to run with a supercharger of some sort is made to have that compressed air. When it does not have it you have a very low compression engine and some research on most roots type blowers will show that fuel builds up in a blower that is not turning and can blow the thing up from what I recall reading years ago.
Just figured I would mention this since I think it was in car and driver or something and I was reading one of their aniversary mags where they go over stuff they have done for articles in the past.
I ran some searches and the actual mad max stuff is everywhere and I can't find anything resembling what I am thinking I read 10 or 15 years ago.
However, as already mentioned an engine made to run with a supercharger of some sort is made to have that compressed air. When it does not have it you have a very low compression engine and some research on most roots type blowers will show that fuel builds up in a blower that is not turning and can blow the thing up from what I recall reading years ago.
Just figured I would mention this since I think it was in car and driver or something and I was reading one of their aniversary mags where they go over stuff they have done for articles in the past.
variable boost superchargers have been around since the 30's... Eaton makes one with a bypass valve for variable boost... Paxton made the VR-71 using a springpack to vary boost..
but none with an "on/off" like Mad Max that i know of..
but none with an "on/off" like Mad Max that i know of..
BustedTrojan said:
A Weiand 144ci is a belt-driven Roots-type supercharger. There's no "waste" to put a wastegate on. The only way to control boost with that type of blower is to change pulleys - not exactly the easiest thing to do in the middle of a run...
