School me on supercharging a 360

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hey Jack....

Dont mean to hijack.....but you should really consider all your forced induction options.

A Single Turbo Small Block would be streetable, yet viscous on demand.
Just Imagine this, with a Mopar LongBlock:
V8singleturbo.jpg


Vs.

Supercharged360.jpg




I respect cubic dollars either way.
I will Butt Out now.
Prine
 
I have an Offenhauser circle 360 intake but it looks slightly different from yours center divider is notched was yours built up for some reason?
 
I looked at the photos better and see that the divider runs right through.
 
I didn't read through all this but there seems to be a lot of misleading and completely ridiculous info being posted. Take it from those that have built supercharged street cars and ask everyone you can and do your homework before you spend one penny on a blower and don't take short cuts to save a buck because it will cost you $100 for every buck you try to save.

Don (fstfish66) knows what he's talking about and I did see a few other helpful comments but if someone tells you that you can run 15+ pounds of boost with a roots blower on pump gas, they're full of it. I'm running 8.5 compression pistons and my blower is over driven 3% making almost 7 pounds of boost and my final compression is 12.4-1 which is MAX for pump gas. If I had a lower comp piston I could bump the boost up some but the amount of boost is calculated by your comp, cubic inches and the amount of drive you're running and each engine is different. You want to keep the final compression under 12.5-1 no matter what your combination is.

As far as heads, they make a huge difference with how the engine will run, as mentioned above the blower is forcing air down the intake and if the heads don't want to flow, you will have nothing but heating issues. Get yourself a good set of aluminum heads and port them, the aluminum cuts down on the heat and a good port job will make them flow.

You definitely want to go with a good pair of blower carbs, I'm running a pair of 750 Demon blower carbs and they ran perfect right out of the box. They are a little pricey at $550 each but they were well worth it.

Unless your running practically no boost at all, DON'T run a stock lower end, that's a short cut you will regret. You need a good set of forged pistons as well as a good set of rods and a forged crank. A girdle would also be a big plus if your wanting to run any kind of power.

Dyers and BDS are both good companies, Weiand don't make anything for a small block Mopar. I found though that a lot of the boost numbers Dyers has posted is off from every other boost chart I found in books and online so keep that in mind when making your decisions.

You will also find that out of 20 people experienced with roots blowers you ask, you will get at least 20 different ways of doing the same thing so ask everyone you can and read as many books on supercharging that you can and it will get a lot easier to make the right decisions. A couple good books I found were Street Supercharging by Pat Ganahl and Super Power a do it yourself guide to turbocharging, supercharging, fuel-injection & nitrous-oxide.
 
Kelly, always feel free to jump in with your opinion. I know you are big on turbos,but you knowledge on boosting engines is invaluable.

Jack
 
Blownfish, that is some of the best advice that has been presented yet. I am taking all of the info in and will get some of the books that are being mentioned throughout this thread. Like I have said, I don't want to spend any more than I have to, but I won't cheap out either.

Jack
 
The essentials for Boost are the same across the board for internal combustion engines.

Low Compression CR (below 9:1 static CR)
MLS Head Gasket(s)
O-rings cut into the head, for sustained boost over 30 psi
ARP Head Studs/Bolts
Forged Pistons with loose ring gaps (.019"/.022")
Forged H Beam Rods
Forged Crankshaft
HV Oil Pump
Copper Spark Plugs

Adequate fuel system....proper octane.

Heat is your enemy.
 
I would also like to add that with a turbocharger system....changing your boost level is as easy as turning a door knob.....really:
incarboostcontrol.jpg


and that going from 6 psi with a roots blower to 8-10 psi requires:
beltconfig.png


my .02 :read2:
 
Kelly,

I read your post above on what is required for 30 psi. I was wondering what you think would be needed for parts with boost in the 10 to 12 lb range with a compression ratio of 8 to 1 static.

Now, off to look for the book called "Street Supercharging".

Jack
 
10-12pounds is alot if you are doing it on the street, i have not done alot of work on blown engines myself more than that i am in the proces of building my own first blown engine but i can tell you that i have a friend with a 383 #¤%&&smallblock with a pretty big blower cam and alitle under 8:1compresion and that thing wont take more than about 7 pounds of boost on pumpgas since the blower makes so much heat.. at 7pounds that 383 made a very real 600hp and the torque is fully capable of basicly blowing the tires of from under the car at 60mph,thats called torque in excess....
i would read anything blownfsh writes carefully he knows alot about this and there is no replacement for a rocksollid shortblock when it comes to blown engines
 
I have been talking to Dyer's. They recommend a 6-71 with 6 to 8 lbs of boost with an 8 to 1 compression ratio. Anything over that and they believe I will get into heat issues. They also can sell me a kit which includes all polished items for less than $3000 as long as I supply the intake and ship it to them to make sure all is going to work. Sounds like a decent deal to me for all new components. I would still have to buy the carbs and fuel system which adds up quick.

Jack
 
yep it all adds up very quick,its almost like the blower and manifold is the cheap parts when the whole picture is seen...
i got a billet intakemanifold being made by a small local machineshop and it sure isnt cheap but seeing the big picture i dont care anymore about what the cost is for a large part
 
Prine said:
The essentials for Boost are the same across the board for internal combustion engines.

Low Compression CR (below 9:1 static CR)
MLS Head Gasket(s)
O-rings cut into the head, for sustained boost over 30 psi
ARP Head Studs/Bolts
Forged Pistons with loose ring gaps (.019"/.022")
Forged H Beam Rods
Forged Crankshaft
HV Oil Pump
Copper Spark Plugs

Adequate fuel system....proper octane.

Heat is your enemy.
Click to expand...

On a single Turbo SBM application to get around 700-800 Rwhp, what size turbo would it require and what exact set up would you use etc?

Would it need to be Intercooled?

Same question with Dual Turbo's?

This would be on a STROKED 410 CI Small Block!
 
I started reading the "Street Supercharging" book today. I'm about 1/3 the way throught it. I think my head is going to explode. LOL

Jack
 
There was a magazine engine build not too long ago. I think it was a mopar action, Oct 2010. They used a very low dollar almost stock 360 with smog heads and 1.88 valves. The result was about 400 h.p and over 450 ft/lbs tq!

They simply bolted on a paxton kit ($3500) and a mighty demon 750 that was built for blow through. The cam was a small comp extreme energy .462/.470 lift 262/270 duration so very good street manners.Crane adjustable rockers were the only other non stock part.

Federal mogul forged pistons and eagle rods were thrown in too but they dont make more power,just help durability.
 
Hey Guys
I just picked up a 72 demon with a 340 and a 471 blower. First blower i have ever had so i'm a little on the paranoid side of it all right now. I have driven it a few times now and my temp gets up to 190 sometimes even 200 but then i get scared and pull over. Then i keep the waterpump running and the fan to cool it down. Now does this all sound way to hot to you guys?

My duster has always ran cool as a cucumber never over 170..

I'm not sure of the boost in the demon as the guy i bought it from wasn't sure of how much, there is a vacume gage in the car so is there a way to figure out the boost that way or do you have to measure the bottom and top pulley?

Its the same kind of problem with my Lil Red and my 4X4 they all seem to get up to 190 or so too which seems hot to me.

I cooked a 360 once so now i'm really paranoid on temps.

Here is some of the info on the motor set up.
9:1 compression
Solid lifter setup
Forged Pistons
J heads heavily ported, stainless steel valves, single groove retainers .600 lift
Aluminum 1.5 ratio roller rockers
Aluminum hold down blocks on the rocker shafts
Hardened push rods
Steel crankshaft, balanced assembly
750 Holley
727 trans with 3500 stall
5:13 rearend
aluminum be cool rad, electric fan, electric motor for water pump

So if anyone has any idea's for me to keep it cool, that would be great.
Thanks
Jason
 
The magazine blower project engine was only a 318 and made that much power. It just goes to show what forced induction can do for you.
 
the motor in the magazine was a 360 motor with what they called the worst small block mopar heads,,,if i were paxton i wouldnt of wanted that artice to come out for almost 4 grand in parts,,not including if u paid some one to install it it only made 60 more horse power,,,blowers commonly make 45 to 50 % more power,,, 4 grand for 60 hp ??? you can get that with a good cam selection and heads,,for a lot less,,,


demon 340 with a 4.71?? are you sure its a 4.71 ??? and not a 144 or 177 under the hood blower ??? if its truly a 4.71 that blower is too small to make power with out being pushed so hard it wil make a ton of heat,,,,

4 x 71 = 284 cubic inch,,any thing bigger and its just a hot piece of eye candy,,,lets see a pic of the blower and motor,,,a good fan in the proper location,and 4 row radiator will keep it kool,,or a big 2 row aluminum radiator,,


i run a standard factory style radiator 4 row with a water pump mounted fan,,7/8 of an inch fro mfan blade to radiator,,,178 temps all day long and when its 102 degrees out its about 181 degrees,,,
 
Well the guy i bought it from said thats what it was. I'm not really sure how to tell the 471/671/871's apart. Here is a pic though.. Let me know what you think. The old rad is gone and a aluminum becool one is in now..
 
ok hard to tell from that pic,,doesnt look likea 4.71 but looks smaller then a 6.71,,, measure it from front to back,,,but not the snout,,,the snout is the long front piece with the upper pully on the end,,, just measure from front case to rear and ill compare to mine OLOR]
 
Been tossing around the idea of a blown big block. Am I correct in assuming that if I were to run efi it will need injectors above and below the blower, assuming it is a roots style?
 
inkjunkie said:
Been tossing around the idea of a blown big block. Am I correct in assuming that if I were to run efi it will need injectors above and below the blower, assuming it is a roots style?
Click to expand...

Use a 400 block Doug. The 440 mains tend to crack with blower abuse.
 
Hey Fstfish
Just measured the blower. From front to back its measure's length 14.5", height is 7.5", Width is 11.25...
 
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