Blower tech 101

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340sixpack

340sixpack

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Thinking about the next project and wanting to put a blower on the dart.I know nothing about them so im looking for some insight.Pros,cons,etc.

671 vs 871 big difference?

Will more than likely use a 440 as the car is set up for it already and i have a
block already prepped.Automatic w/manual valvebody.

Street car,probably limited track use,so it will be set up as a street car.Full tub or mini-tub not sure on that yet,more than likely mini-tubbed as i want to
keep the back seat.

Need some specs.Thanks
 
It had 906 heads with 2.14 1.81 valves, mild custom blower cam ,solid flat tappet with 8-1 pistons , 4.30 gears and would pull as hard in 2nd and 3rd as first gear, fun street car.
 
They are fun, but plan on spending three times the cost of the blower to build the engine and set everything up correctly, four times in my case. Everything from the carb to the rearend has to be thought out and set up with the blower and boost in mind.

I wouldn't go with an 871 that is just over kill for street use.

I have 8.5-1 in my 416, I was going to run 8-1 but that was a screw up on JE pistons part. This limits me on boost, I have mine over driven with about 6 1/2 pounds right now but I will raise that once I get everything ironed out.

There are a few parts I would highly recommend, a pair of aluminum heads, an Edlebrock water pump, a good aluminum radiator and Spal fans. Cooling is the biggest problem people have with blown street cars with boost and power.

Another thing would be is talk to as many people as you can at shows and the track that has or had a blower car and ask them what there thoughts are and what troubles they had. You will find out of 12 people, you will have at least 9 different thoughts and or problems. Never take just one guys suggestions, soak up as much info as you can so you can make your own decisions that will work for you.
 
currently in the process of finishing a 440 8-71 build. I didn't know much about blown engines when all of this started about 2 years ago (a few guys on here might remember) If you have the time to read, there is a book called "Supercharged" written by Corky Bell. Of all of the research I have done on the topic, this book was the most informative. It has the answers to pretty much any question you could conjure up. If you're more of the "video" type learner, go to badasscars.com. Arron Johnson has a video on there, specifically for building supercharged engines. What kind of heads, cam, crank, pistons, etc...... very informative. Those are the two best sources I have found in my building process (and all the guru's on here) Good luck with your build and I hope everything goes smoothly.
 
first of all,, what are you going to do with it ?? street drive it ??/local shows ?? cruise nights ???

the difference between 6.71 vs 8.71 is the cubic inch size of the motor you plan on building,,,and its purpose,and your buget,,,if you want to make more then 5 or 6 pounds of boost on a 440 you will need a 8.71 blower,,

boost is made by a combination of compression and drive on the blower,,the more drive the more boost = heat,,, the bigger the blower the more boost created with less drive= less heat,,

on a non computer/tuner motor 93 octane pump gas will only support 9 pounds of boost,,with out detenation,,,,

also another factor cam center line,,vs cylinder pressure vs heat,,,,112 center line is doable on the street but a 114 center line makes more cylinder presure/power/heat

get a book on super charging and read up on it before you walk in to a speed shop and order junk that they have no clue about,,


if your looking to build a street cruise night blower motor,,cal big AL,s toy box he has reasonable pricing on complete motors


i have a 340 7.76 true compression iron heads cam 112 center line 6% under driven on the blower 6.71 blower i make 13 pounds of boost,,fun street car,,, car runs at 178 degrees most of the time,,when its over 88 and humid out it runs 181 degrees,,,with a 4 row radiator and standard flex fan,,,

carlisle 08 370 - Copy.jpg
 
One thing against the big roots style is having to cut your hood and then getting caught in the rain if your plan is to cruise the streets with it. a lot of guys run the prochargers for that reason. Also prepare for a lot of heat with a supercharged engine, the heat from the engine made the inside of my car feel like a sauna in the summertime, my dads car had a blower on his demon 340 and it was the same way
 
All of the above fstfish and some drag racing a few times a year but concentrating on mainly a street machine.Looks like the 6.71 should
be plenty for what i want to do.Not looking to break any speed records
or anything like that,just a good running blown engine thats dependable
for what it is.

Good point on the rain factor blown71,I usually dont stray far from home unless going to the drag strip and the cars are a trailer then,any other time the cars dont come out if raining and dont leave town if theres even a chance.

My main reason for using the roots type is car shows,all i ever see are the chevys with them,we need a mopar around here with one stuffed through
the hood!And they just look bad a$$!
 
If you are planning on taking to car shows, you better get used to lots of attention and trophies:-D

Here is a shot of dads Demon with the blower, It was a crowd pleaser with the sound and looks of it.

Car.jpg
 
blown71duster said:
If you are planning on taking to car shows, you better get used to lots of attention and trophies:-D
Click to expand...


I can vouch for the attention, if I had a nickel for every idiot in the beat up rice burner that wants to race I could build another car.
 
fstfish66 said:
then you need a set of these,,,
Click to expand...

I know it,ive planned on tubbing this car the past 10 yrs already,a buddy of mine who has done several race cars offered to do it for a pipe bending machine($1200.00)With my limited time now thats hard to pass up.I may
be able to do it and save the back seat with some modifications to it.Thats just too impressive seeing all that rubber under there!
 
340sixpack said:
I may
be able to do it and save the back seat with some modifications to it.Thats just too impressive seeing all that rubber under there!
Click to expand...

What year Dart are we talking about?

You will have to use ladder bars but I still have my rear seat, it took a lot of thought and work though in order to have it still fold down.
 
Blownfish said:
What year Dart are we talking about?

You will have to use ladder bars but I still have my rear seat, it took a lot of thought and work though in order to have it still fold down.
Click to expand...

67.There is a good amount of room there to work with,like you said it will
require some engineering to make right.
 
340sixpack said:
67.There is a good amount of room there to work with,like you said it will
require some engineering to make right.
Click to expand...


That will be easy, it's stationary. I had to modify a fold down seat and still have it fold down.
 
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