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> Anyone tried an aircooled Flat 8, With two fours?
r_towle
post Jan 28 2005, 12:49 PM
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Has anyone tried to build a flat 8 with two type 4 motors?

Theoretical questions.
Assumptions
2 motors each producing 100 HP and 100 Lb/ft of Torque

The motors are end to end, front to rear.
The cranks are fastened together either bolted or welded.

1) Would you get 200hp and 200 lb/ft or torque? or is there some multiplier...seems like you would produce more torque..

2) could it be done with a single ignition system available for sale off the shelf.

3) could you do it without two distributors? crank fired ignition system..I am thinking that there could be a wheel placed in between the motors to give you something to time from.

4) I am assuming either a nice FI system, or four carbs.

Has anyone done this?
I would like to see some articles or web pages if this has been done in the aircooled world...

Thanx in advance
Rich
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Mueller
post Jan 28 2005, 01:03 PM
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yep, a few have been done........I know I've posted pictures as a well as a few others....

for a 914 application, the motor wouldn't fit unless you moved the assembly back a few inches...even without the cooling fan, I don't think it would fit in the stock location

for the cost/time/ it would take to make one, there are a dozen better engine choices unless one just wants to do it for the novelty of doing it....

since it's already been done a few times, there is no novelty in it....nothing ground breaking....kinda boring (IMG:http://www.914world.com/bbs2/html/emoticons/smile.gif)
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sanman
post Jan 28 2005, 01:05 PM
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I thought of it but I think it would be


too long to fit in a 914 and
you would loose 1 fan for cooling

now on the other hand If some one made a 6 case that took t4 or t1 P/C,rods, and heads it may work
but that just my thoughts

forget it! you would need a 6 crank, and cam
Just get a chevy v8 or a porsche 6 and be done (IMG:http://www.914world.com/bbs2/html/emoticons/biggrin.gif)
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r_towle
post Jan 28 2005, 01:05 PM
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i was hoping you would answer...you always think outside the box...

So what about the torque numbers...is it simply double???

It just seems that is would be multiplied somehow..
and where would i find some pics....
Rich
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andys
post Jan 28 2005, 01:08 PM
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It's been done both ways. I saw a pic years ago of a specially cast block for 8 cylinders. Also, the Fittipaldi brothers raced a Bug in Brazil where they coupled two motors together similar to what you describe, in a mid-engined configuration. They were apparently very successful with this car. Interesting way that they ducted air to cool the motors: they slanted the windshield back into the driver compatment. Air was ducted over the driver, then down to the two motors.

Andy
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r_towle
post Jan 28 2005, 01:14 PM
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honestly cooling seems like a simple part of it ...
A custom horizontal system would work.

What are the numbers...in theory???

Rich
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Mark Garriott
post Jan 28 2005, 01:22 PM
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Double displacement does not usually equal double torque or horsepower. Not sure why.

In WWII, Pratt & Whitney took 2 14 cylinder radials and joined them onto a single case, resulting in a 28 cylinder that made 50% more HP. In the '90s Honda simply upped the size of a 600cc four to 900cc and got 20% more power (50% more displacement). Granted, the stock T4 is restricted, so using a RAT 2270 as a basis, maybe 250 HP would come from a T4x2. Just guessing.
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nebreitling
post Jan 28 2005, 01:36 PM
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i would think that you could never get double the power. maybe 150%, 175% if lucky.

entropy's a bitch.
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Jake Raby
post Jan 28 2005, 01:59 PM
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Already have a print in with moldex on the crank.
Already dissected 4 engine cases to find the best mating points.... Just need time
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machina
post Jan 28 2005, 02:19 PM
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asked the same question a while back....

here's what I got.


Attached image(s)
Attached Image
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Mark Garriott
post Jan 28 2005, 02:23 PM
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Hans Dahlbeck? Isn't he the brain donor in 'Young Frankenstein'? Seems fitting.
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machina
post Jan 28 2005, 02:54 PM
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QUOTE (Cloudbuster @ Jan 28 2005, 03:23 PM)
Hans Dahlbeck? Isn't he the brain donor in 'Young Frankenstein'? Seems fitting.

No, I think you mean Mr. Abby Normal (IMG:http://www.914world.com/bbs2/html/emoticons/wacko.gif)
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BigD9146gt
post Jan 28 2005, 03:33 PM
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You'd be better off starting with two early 2.0 911 engines. By cutting the center two cylinders out of one case and placing them in the center of the other case, you add two cyclinders to an already superior design. Having small cylinders to begine with (width wise) helps keep the lenth of the motor down too. Then a Scat crank and some custom cams, you have the better overhead cam design, better cooling, and better head flow. Plus with the early cases, they're all aluminum like the 914 case, making welding them together easier... and stronger.
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Jake Raby
post Jan 28 2005, 03:47 PM
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Nah.... Can't make a statement with a 911 engine!

Plus, they cost too damn much to play with at this level..

I'm using 964 heads though..

Engine will go in a mid engine 1961 VW Single cab truck, under the bed.....
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r_towle
post Jan 28 2005, 05:15 PM
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QUOTE (Jake Raby @ Jan 28 2005, 01:47 PM)
Nah.... Can't make a statement with a 911 engine!

Plus, they cost too damn much to play with at this level..

I'm using 964 heads though..

Engine will go in a mid engine 1961 VW Single cab truck, under the bed.....

I had a funny feeling you would be looking at this at some point in your life...

I may try to get this done, just to see if it can be done smoothly, easily, and if it has benefit.

I am thinking why not use the heavy strong crank and push rods, lighter cylinders and pistons, and turbocharge the whole thing....
It would be a cool way to use parts that may be inferior for a hopped up T4 motor, but rugged enough for a T8 motor.

Rich
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Mueller
post Jan 28 2005, 05:29 PM
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QUOTE
I may try to get this done, just to see if it can be done smoothly, easily, and if it has benefit.


if it was even one of those choices above, you'd see more than a few running around (IMG:http://www.914world.com/bbs2/html/emoticons/smile.gif)

it'll have all of the same problems or issues a /4 has, the only benifit is if you are trying to reach a certain hp level...if stock /4 has 100 and you want 175, then the /8 should be able to give you 175 horsepower easier than the /4

I'm betting that hp per liter would be the same and if anything, the /8 would be under more stress if you try to push it too hard.....
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jwalters
post Jan 28 2005, 06:06 PM
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Sooo Close.......
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(IMG:http://www.914world.com/bbs2/html/emoticons/smile.gif) An aviation supplier / builder / design company called "Able Experimental" has done this with full success--albeit a T1 engine---Developed over 210 HP and almost 280 ftlb of TQ---key was 90.5mm P/C and a 80mm stroke---it was made for experimental aircraft--the same company makes the altimizer carburetor--this is an injected carburetor which automatically compensates the mixture for changes in air density--very popular carb in aviation.
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Jake Raby
post Jan 28 2005, 06:10 PM
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It won't cost a whole lot for me to do it, other than the crank and heads... The rest of it I have gobs of....


Its all in time and putting the imagination to work..

Its no fun if you don't push the envelope.... I'm sure I'd learn something beneficial to my other normal engines from doing it!
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Mueller
post Jan 28 2005, 06:13 PM
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QUOTE (jwalters @ Jan 28 2005, 05:06 PM)
(IMG:http://www.914world.com/bbs2/html/emoticons/smile.gif) An aviation supplier / builder / design company called "Able Experimental" has done this with full success--albeit a T1 engine---Developed over 210 HP and almost 280 ftlb of TQ---key was 90.5mm P/C and a 80mm stroke---it was made for experimental aircraft--the same company makes the altimizer carburetor--this is an injected carburetor which automatically compensates the mixture for changes in air density--very popular carb in aviation.

considering thier 100 hp /4 motors cost $6000, I'd hate to see the price of that /8 motor (IMG:http://www.914world.com/bbs2/html/emoticons/smile.gif)

they do have some cool stuff...
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jwalters
post Jan 28 2005, 06:28 PM
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Sooo Close.......
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(IMG:http://www.914world.com/bbs2/html/emoticons/smile.gif) Yea they do---imagine there is allot of machining and welding up a crank and cam and MAGNESIUM case ( Can you say,,sparkler??) Those engines require even more prep than or = to Mr. Raby does to his to make them a viable high power aero engine If the balances of the entire assembly are off more than .10 inches per second the crank will grenade itself--even at the max rpm of 3600 these engines are rated for--and bye bye propellor--the cranks are rough prepped by CB's--they actually forge a crank just for this purpose---kool stuff indeed

Don't know ifn I would ever get into something like that, manufacturing wise--the liability factor is an ass pucker!!!

But it would be kool to see Jake the man do it---400+HP anybody???

I myself have a really doable engine make-up I am dreaming of---it uses the stock bottom end--but the cyl and up is off the shelf from a manufacturer that has been in business since 1908--

Not going to reveal it yet,,need to get measurements and geometric values looked at--plus I don't want to get sand bagged just yet! (IMG:http://www.914world.com/bbs2/html/emoticons/laugh.gif) (IMG:http://www.914world.com/bbs2/html/emoticons/hide.gif)
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