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Big block with 6/71 roots project #1467540
07/14/13 06:52 AM
07/14/13 06:52 AM
Joined: Mar 2013
Posts: 13
Loire Atlantique
Filex Offline OP
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Filex  Offline OP
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Loire Atlantique
Hello all,

I recently bought an naked (1969) 440ci and I want install a 6/71 supercharger.

I only got the block, I have to buy all the pieces but we don't find informations in french forums.

Currently I have a 360ci on my Coronet, I rebuilt it with some Edelbrock parts but i don't have knowledge on a supercharger preparation.

I don't want 800HP, it's just for fun and look, 450-500HP is enough.

I think begin by the crankshaft, do you have an idea ?

And what are the best roots for big block mopar ?

Thanks (and sorry for my english mistakes).


Felix

Re: Big block with 6/71 roots project [Re: Filex] #1467541
07/14/13 10:11 AM
07/14/13 10:11 AM
Joined: Jan 2003
Posts: 24,562
Brookeville, Md
Mr.Yuck Offline
Not enough dumb comments...yet
Mr.Yuck  Offline
Not enough dumb comments...yet

Joined: Jan 2003
Posts: 24,562
Brookeville, Md
no need for a 671 on a 440 to make 400-500hp, that can be done w/ a 9:1 pump gas N/A 440. You can make an easy 650 w/ a 671 and 440. An 871 would be better if you are starting from scratch. I recommend the book "Turbo Charging, Super Charger and Nitrous Oxide" It will explain a lot and show you the do's and don'ts. Good luck with the build.
good looking car.


[IMG]http://i66.tinypic.com/pui5j.jpg[/IMG]
Coming soon!!!!
Re: Big block with 6/71 roots project [Re: Filex] #1467542
07/14/13 10:26 AM
07/14/13 10:26 AM
Joined: Oct 2005
Posts: 268
South Central Pa
webemopes Offline
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webemopes  Offline
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South Central Pa
i also used a 69 block and crank.you can use a later 440 piston or use aftermarket forged pistons like i did. mine are 90 thousandths down in the bores .i have edelbrock performer heads and that gives me an 8.2 to 1 compression.i have an 871 on but right now am only spinning it at 13 percent underdriven.i agree that an 871 would be better for a 440 and just underdrive it to get the desired hp. 600 is easily obtainable with a blower

Re: Big block with 6/71 roots project [Re: Filex] #1467543
07/14/13 10:33 AM
07/14/13 10:33 AM
Joined: Jan 2003
Posts: 9,866
Weddington, N.C.
Streetwize Offline
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Streetwize  Offline
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Posts: 9,866
Weddington, N.C.
Filex,

Congratulations on your project. For your supercharged 440 I would suggest this as a 'general' outline for a very streetable 600 hp supercharged 440.

A forged (approx 1971 or earlier) 440 crankshaft
Aftermarket forged H or I beam connecting rods
Forged 'D' dish pistons which allow for both quench and between 8.5 and 8.8:1 static compression ratio. Pistons are specifically available for supercharged engines and typically feature the ring pack being set slightly lower from the combustion surface of the piston, this is recommended but not required. Follow the piston mfg recommendation for ring type, gap and finish hone on the cylinder bores.
A well-machined block (sonic checked, square decked, line honed with ARP main studs, finished honing with 'deck' plates with enlarged oil passages as outlined in the mopar performance Engine manual).
An aluminum cylinder head such as the Edelbrock performer RPM (closed chamber approx 84cc as advertised) with mild porting and combustion chamber polishing would be helpful. Supercharged engines for long term durability tend to benefit from a wider valve seat margin surface than you might want on a fully ported set of heads, however some judicious contouring of the bowl area and guide contouring is still helpful).
Good cooling is essential on a supercharged engine, a supplemental oil cooler and larger transmission coolers are good investments for dissipating as much heat as is practical.
For a cam with about 8-10psi of boost I would run a hydraulic flat tappet with approximately 242 degrees @.050 and .540 lift on the intake and approx 250 degrees @ .050 on the exhaust on 112 lobe seperation angle and installed +4 at 108 intake centerline. This will give you a very broad powerband and will idle deceptively smooth at 800-850rpm.
I would run a custom calibrated single 4 barrel carb like a pro-systems 950hp 4150 series carb with a 16" x 4" high air cleaner. Run a large capacity (min 110gph and 140 hog would be better) electric fuel pump.
A ported high volume oil pump with a minimum 7 quart wet sump system will be fine, the milodon low profile is best for ground clearance (since the 6-71 adds a lot of weight to the front of the car)
For a distributor, I've had very good success running a custom calibrated unit with approx 14-16 degrees of initial advance and a comparatively slow mechanical curve of 20 degrees all in by 3000 rpm, unlike a normally aspirated car you don't want a quick full advance for part throttle roll-on (normal driving) power.
Headers should be 2" primaries with 3 1/2" collectors going to a low restriction dual 3" system.
A "tight" 10" Turbo-action (nominal stall approx 3000, they sell "loose-medium and tight" stalls) would work very well with 3.55 gears, behind the blown 440 it would Footbraked stall approx 3800 rpm but would still fell very good at highway cruising speeds and not run hot. A blower will increase the stall and flash of any converter compared to a normally aspirated motor, so a big mistake people make is to go too loose and they simply can't put the power to the ground.

That's IMO a solid base to consider for a very streetable 6-71 blown 440,(I've built several)... hope it helps!

Last edited by Streetwize; 07/14/13 02:48 PM.

WIZE

World's Quickest Diahatsu Rocky (??) 414" Stroker Small block Mopar Powered. 10.84 @ 123...and gettin' quicker!

https://www.youtube.com/watch?v=-mWzLma3YGI

In Car:

https://www.youtube.com/watch?v=PjXcf95e6v0
Re: Big block with 6/71 roots project [Re: Streetwize] #1467544
07/14/13 01:10 PM
07/14/13 01:10 PM
Joined: Sep 2005
Posts: 12,481
Chino Valley
RodStRace Offline
I Live Here
RodStRace  Offline
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Posts: 12,481
Chino Valley
Wize, great info!

I see that you are providing more cam on the exhaust side. Would you suggest also working the exhaust port more, or just go with a typical porting job across both ports?

Also, since you don't mention it, I'd assume no vacuum advance?

What about throttle pressure to the trans? Is there a tried and true setup that works properly and is reliable?

Any particular drive and intake you like better than others, and why?

Figured I'd pick your brain on these, since they are also part of the deal and you seem to have worked with a few.

Re: Big block with 6/71 roots project [Re: RodStRace] #1467545
07/14/13 02:00 PM
07/14/13 02:00 PM
Joined: Jan 2003
Posts: 9,866
Weddington, N.C.
Streetwize Offline
master
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Weddington, N.C.
Rod,

I've had some success running a vaccumm advance using the crane Adjustable diaphagm dialing it pretty much all the way out, but that was on a 4 speed car.

a blower drives about like a n/A car until you nail it (motor can't make boost until you give it enough air) but once you do you don't need a ton of advance because the cylinder pressure is much higher at low rpm than you can possibly achieve N/A. Drivability is great once you get it sorted though....especially on misty mornings with a little coolness in the air.

I would definately consider a methanol injector like MrYuck runs on his sixpack 440, I see no downside to that at all.

Trans line pressure, never gave that much thought because I always ran MVB's or 4 speeds.

I like the Dyers supercharger set-ups, manifolds need a little port match and clean-up but nothing special. I ran a 383 with a V6-71 and only the 2" belt drive back in the early 80's that worked really well, the standard 3" drives on the 6-71 and 8-71's always seemed to do well, fatter belts/drives can play havoc with radiators and cooling in terms of fitment. A lot of people used to run their belt tensions too tight which adds a lot of strain to the bearings and crank snouts. Too tight will cause the belts to want to walk, and it's not only tension it's parallelness that also comes into play.

I used to put a few drops of Pro-blend in the gear oil, it seemed to cut the friction down a tad because the whine changed pitch slightly ( but noticably)

Like I said HEAT is the one thing people probably don't realize about blowers, once you run them hard you can actually start losing a bit of power because that air builds up a lot of heat. 600 hp also makes a lot more HEAT than 400 hp, how you wick it away is important if you want it to live, that's in part why I like a bit of a wider valve seat on an endurance street blower motor, it gives just a bit more area for heat transfer (since any goven valve is closed well more than 1/2 the time) from the exhaust valve back into the head/cooling system.


WIZE

World's Quickest Diahatsu Rocky (??) 414" Stroker Small block Mopar Powered. 10.84 @ 123...and gettin' quicker!

https://www.youtube.com/watch?v=-mWzLma3YGI

In Car:

https://www.youtube.com/watch?v=PjXcf95e6v0
Re: Big block with 6/71 roots project [Re: Streetwize] #1467546
07/14/13 02:15 PM
07/14/13 02:15 PM
Joined: Apr 2007
Posts: 2,026
Trumbull,CT.
J
jim sciortino Offline
top fuel
jim sciortino  Offline
top fuel
J

Joined: Apr 2007
Posts: 2,026
Trumbull,CT.
Quote:

Felix,

Congratulations on your project. For your supercharged 440 I would suggest this as a 'general' outline for a very streetable 600 hp supercharged 440.

A forged (approx 1971 or earlier) 440 crankshaft
Aftermarket forged H or I beam connecting rods
Forged 'D' dish pistons which allow for both quench and between 8.5 and 8.8:1 static compression ratio. Pistons are specifically available for supercharged engines and typically feature the ring pack being set slightly lower from the combustion surface of the piston, this is recommended but not required. Follow the piston mfg recommendation for ring type, gap and finish hone on the cylinder bores.
A well-machined block (sonic checked, square decked, line honed with ARP main studs, finished honing with 'deck' plates with enlarged oil passages as outlined in the mopar performance Engine manual).
An aluminum cylinder head such as the Edelbrock performer RPM (closed chamber approx 84cc as advertised) with mild porting and combustion chamber polishing would be helpful. Supercharged engines for long term durability tend to benefit from a wider valve seat margin surface than you might want on a fully ported set of heads, however some judicious contouring of the bowl area and guide contouring is still helpful).
Good cooling is essential on a supercharged engine, a supplemental oil cooler and larger transmission coolers are good investments for dissipating as much heat as is practical.
For a cam with about 8-10psi of boost I would run a hydraulic flat tappet with approximately 242 degrees @.050 and .540 lift on the intake and approx 250 degrees @ .050 on the exhaust on 112 lobe seperation angle and installed +4 at 108 intake centerline. This will give you a very broad powerband and will idle deceptively smooth at 800-850rpm.
I would run a custom calibrated single 4 barrel carb like a pro-systems 950hp 4150 series carb with a 16" x 4" high air cleaner. Run a large capacity (min 110gph and 140 hog would be better) electric fuel pump.
A ported high volume oil pump with a minimum 7 quart wet sump system will be fine, the milodon low profile is best for ground clearance (since the 6-71 adds a lot of weight to the front of the car)
For a distributor, I've had very good success running a custom calibrated unit with approx 14-16 degrees of initial advance and a comparatively slow mechanical curve of 20 degrees all in by 3000 rpm, unlike a normally aspirated car you don't want a quick full advance for part throttle roll-on (normal driving) power.
Headers should be 2" primaries with 3 1/2" collectors going to a low restriction dual 3" system.
A "tight" 10" Turbo-action (nominal stall approx 3000, they sell "loose-medium and tight" stalls) would work very well with 3.55 gears, behind the blown 440 it would Footbraked stall approx 3800 rpm but would still fell very good at highway cruising speeds and not run hot. A blower will increase the stall and flash of any converter compared to a normally aspirated motor, so a big mistake people make is to go too loose and they simply can't put the power to the ground.

That's IMO a solid base to consider for a very streetable 6-71 blown 440,(I've built several)... hope it helps!


Reliable, ultra low maintenance, inexpensive and powerful.

I'd use a pair of "blower" carbs, but excellent advice overall.

Re: Big block with 6/71 roots project [Re: RodStRace] #1467547
07/14/13 02:25 PM
07/14/13 02:25 PM
Joined: Mar 2013
Posts: 13
Loire Atlantique
Filex Offline OP
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Filex  Offline OP
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Posts: 13
Loire Atlantique
Thanks all for your answers !

It's a real pleasure to see that people can help me !

@Mr. Yuck : I know I can obtain 500HP without supercharger but I really want it, I looooove the beauty of the roots!

About the book, I choose this :




There are a lot of informations inside, I am reading it !

@webemopes : I have to buy all the parts so I think take all in new. For the heads I agree with you, Edelbrock Performer RPM seems ok !

You think that a 871 is better ? why ? it's for more horsepower no ?

@Streetwize : thank you for your answer ! About the crankshaft, something like that is ok ?

http://www.summitracing.com/parts/esp-444037506760/overview/make/dodge

For the pistons you said there are specifically available for supercharger, where can I find them ?

Indeed I will do check the block by a pro but he said to me that he need a crankshaft for some controls.

Ok for the Edelbrock RPM heads !

for the other infos, I keep all your informations in a file, I want to build the engine step by step, otherwise I will not find the way..

thank you one more time !




I find this table on Holley superchargers :



So I think that something like 8.0:1 static compression ratio with 4psi of boost (10.2:1 effective compression ratio) is good, no ?

Re: Big block with 6/71 roots project [Re: Filex] #1467548
07/14/13 02:41 PM
07/14/13 02:41 PM
Joined: Jan 2003
Posts: 9,866
Weddington, N.C.
Streetwize Offline
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Those are very general outlines on boost vs static compression, what is most critical is Dynamic compression which is impacted by both static and cam timing, particularly your intake closing event. Also the use of aluminum cylinder heads allows better heat dissipation as well and carefully considered effort towards your fuel and ignition timing can allow you to make more boost safer and more efficiently. Those 'rule of thumb' charts I suspect are designed to deter people from going too wild with their selectoons knowing most are going to simply bolt a blower on their existing engine, not for those carefully selection parts for a purpose built 'blower motor' like you and I would be building.


WIZE

World's Quickest Diahatsu Rocky (??) 414" Stroker Small block Mopar Powered. 10.84 @ 123...and gettin' quicker!

https://www.youtube.com/watch?v=-mWzLma3YGI

In Car:

https://www.youtube.com/watch?v=PjXcf95e6v0
Re: Big block with 6/71 roots project [Re: Streetwize] #1467549
07/14/13 03:15 PM
07/14/13 03:15 PM
Joined: Mar 2013
Posts: 13
Loire Atlantique
Filex Offline OP
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Loire Atlantique
ok,thank you !

So to begin, do you think that the link of the crankshaft i posted is right ?

Re: Big block with 6/71 roots project [Re: Filex] #1467550
07/14/13 04:31 PM
07/14/13 04:31 PM
Joined: Jan 2003
Posts: 9,866
Weddington, N.C.
Streetwize Offline
master
Streetwize  Offline
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Posts: 9,866
Weddington, N.C.
Yes although it shouldn't be difficult to find a good forged 440 crank for less, for the same $$$ one could by a stroker crank with 3.90"-4.375" stroke.

I prefer Scat, K1 or Ohio cranks over the Eagle but I'm certain that opinions vary.


WIZE

World's Quickest Diahatsu Rocky (??) 414" Stroker Small block Mopar Powered. 10.84 @ 123...and gettin' quicker!

https://www.youtube.com/watch?v=-mWzLma3YGI

In Car:

https://www.youtube.com/watch?v=PjXcf95e6v0
Re: Big block with 6/71 roots project [Re: Streetwize] #1467551
07/14/13 05:03 PM
07/14/13 05:03 PM
Joined: Mar 2013
Posts: 13
Loire Atlantique
Filex Offline OP
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Loire Atlantique
Ok, I note that !


I will look for other crankshaft

Re: Big block with 6/71 roots project [Re: Filex] #1467552
07/15/13 05:40 PM
07/15/13 05:40 PM
Joined: Mar 2013
Posts: 13
Loire Atlantique
Filex Offline OP
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Loire Atlantique
About the pistons, if I want approximately 8.5 compression, where can I find them ?

Is there especially pistons for supercharging or can I take classic forged pistons ?

Re: Big block with 6/71 roots project [Re: Filex] #1467553
07/15/13 07:27 PM
07/15/13 07:27 PM
Joined: Jan 2003
Posts: 9,866
Weddington, N.C.
Streetwize Offline
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Streetwize  Offline
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For much better results you want a zero deck piston with an inverted dome 'D dish' to ensure quench and lower static compression. Combined with a closed chamber head your blower engine will make much better torque and horsepower than using a traditional "deep in the hole" (piston well below the deck height at top dead center) OEM style piston.


WIZE

World's Quickest Diahatsu Rocky (??) 414" Stroker Small block Mopar Powered. 10.84 @ 123...and gettin' quicker!

https://www.youtube.com/watch?v=-mWzLma3YGI

In Car:

https://www.youtube.com/watch?v=PjXcf95e6v0
Re: Big block with 6/71 roots project [Re: Filex] #1467554
07/15/13 07:31 PM
07/15/13 07:31 PM
Joined: Oct 2007
Posts: 4,205
New York
polyspheric Offline
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The "effective compression ratio" chart is nonsense.
If you examine the numbers, they're simply (atmospheric pressure + boost pressure) ũ ATM, then Ũ the static CR.
Example: 8.0:1 CR with 12 psi boost shows 14.5:1 CR on that chart.
Assuming 14.7 for atmospheric pressure:
(14.7 + 12) ũ 14.7 Ũ 8 = 14.53

What's actually happening?
The effective CR is 12.5:1.
How is that calculated?
Read my article:
http://victorylibrary.com/mopar/blower-engine5.htm


Boffin Emeritus
Re: Big block with 6/71 roots project [Re: polyspheric] #1467555
07/15/13 09:49 PM
07/15/13 09:49 PM
Joined: May 2011
Posts: 4,488
northern,Ohio,USA
C
Clanton Offline
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Clanton  Offline
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northern,Ohio,USA
Quote:

The "effective compression ratio" chart is nonsense.
If you examine the numbers, they're simply (atmospheric pressure + boost pressure) ũ ATM, then Ũ the static CR.
Example: 8.0:1 CR with 12 psi boost shows 14.5:1 CR on that chart.
Assuming 14.7 for atmospheric pressure:
(14.7 + 12) ũ 14.7 Ũ 8 = 14.53

What's actually happening?
The effective CR is 12.5:1.
How is that calculated?
Read my article:
http://victorylibrary.com/mopar/blower-engine5.htm



I am wresteling with the cr stuff myself cuz 14# on a stock head is not the same cylinder pressure on a 70cfm gain aluminum head[about 200 more hp]and is not the same cr.


GOTBOOST!New improved with Victor heads.
http://www.enginelabs.com/mopar-big-bloc...t-of-necessity/
Re: Big block with 6/71 roots project [Re: Streetwize] #1467556
07/16/13 05:58 PM
07/16/13 05:58 PM
Joined: Mar 2013
Posts: 13
Loire Atlantique
Filex Offline OP
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Filex  Offline OP
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Loire Atlantique
Quote:

For much better results you want a zero deck piston with an inverted dome 'D dish' to ensure quench and lower static compression. Combined with a closed chamber head your blower engine will make much better torque and horsepower than using a traditional "deep in the hole" (piston well below the deck height at top dead center) OEM style piston.




I am searching for a complete rotating kit for 8.5 compression but it's hard to find...

In french forums they said that I have to choose a complete balanced rotating kit because if I choose different parts I have to balance them and nobody can do that in France.


Is that true ? It's not possible to buy different pistons, rods and cranks without balance them ?


@polyspheric : I will read your article, thank you !

Re: Big block with 6/71 roots project [Re: Filex] #1467557
07/16/13 06:55 PM
07/16/13 06:55 PM
Joined: Jan 2003
Posts: 9,866
Weddington, N.C.
Streetwize Offline
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I just sent a note to one of my customers in France who has a 416 stroker 340 he built there, maybe he knows of someone who can balance the motor for you.

I would probably call Diamod pistons as they seem to do a fair amount of Dished pistons with quench for strokers, I'm certain they can make a set of 8.5:1 blower pistons for you.

A balanced assembly could a good/more economical way to go as long as you have the block machined and know your deck height and bore size in advance


WIZE

World's Quickest Diahatsu Rocky (??) 414" Stroker Small block Mopar Powered. 10.84 @ 123...and gettin' quicker!

https://www.youtube.com/watch?v=-mWzLma3YGI

In Car:

https://www.youtube.com/watch?v=PjXcf95e6v0
Re: Big block with 6/71 roots project [Re: Streetwize] #1467558
07/16/13 07:20 PM
07/16/13 07:20 PM
Joined: Mar 2013
Posts: 13
Loire Atlantique
Filex Offline OP
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Filex  Offline OP
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Loire Atlantique
Thank you it's really nice !

If I choose parts from differents brands/shop, It is an obligation to balance the assembly ?

I will send an email to Diamod pistons

Re: Big block with 6/71 roots project [Re: Streetwize] #1467559
07/17/13 11:42 AM
07/17/13 11:42 AM
Joined: Aug 2008
Posts: 347
FRANCE, Paris
Chal340 Offline
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Chal340  Offline
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FRANCE, Paris
Hi Bobby how are you? I received your email.

Filex, to balance and prepare your block, the best is to send them at Hauser Racing in UK. I made this for my block and it's less expensive and you will be sure of the result. (As I said you in our french forum )
The best would be to buy a complet kit, cranck, rods and pistons balanced to Mike at MM for exemple and send it with your block for the decking to Hauser.



Quote:

I just sent a note to one of my customers in France who has a 416 sqtroker 340 he built there, maybe he knows of someone who can balance the motor for you.

I would probably call Diamod pistons as they seem to do a fair amount of Dished pistons with quench for strokers, I'm certain they can make a set of 8.5:1 blower pistons for you.

A balanced assembly could a good/more economical way to go as long as you have the block machined and know your deck height and bore size in advance




70 Challenger, A66, 340 ci
Re: Big block with 6/71 roots project [Re: Filex] #1467560
07/17/13 02:32 PM
07/17/13 02:32 PM
Joined: May 2011
Posts: 4,488
northern,Ohio,USA
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Clanton Offline
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I am sorry my comment did not help and is not relative to your goals.I hope you will find the help you need and the parts.


GOTBOOST!New improved with Victor heads.
http://www.enginelabs.com/mopar-big-bloc...t-of-necessity/
Re: Big block with 6/71 roots project [Re: Clanton] #1467561
07/17/13 05:05 PM
07/17/13 05:05 PM
Joined: Mar 2013
Posts: 13
Loire Atlantique
Filex Offline OP
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Loire Atlantique
Thanks for your answers !

I'm ok to buy a complete assembly kit but I just want to know if I choose different parts (crank and rods in 440 source and Mahle pistons for exemple) I have to equilibrate the assembly ?

An other thing, why a 871 is better than a 671 for a street use ? thanks !

Re: Big block with 6/71 roots project [Re: Filex] #1467562
07/17/13 05:19 PM
07/17/13 05:19 PM
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northern,Ohio,USA
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Clanton Offline
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northern,Ohio,USA
The 8-71 will be turned slower for the same hp and a little less heat but in your case I would think you would put that $$ into a water injection kit to run on cheaper fuel instead of the bigger blower.


GOTBOOST!New improved with Victor heads.
http://www.enginelabs.com/mopar-big-bloc...t-of-necessity/
Re: Big block with 6/71 roots project [Re: Clanton] #1467563
07/17/13 06:05 PM
07/17/13 06:05 PM
Joined: Mar 2013
Posts: 13
Loire Atlantique
Filex Offline OP
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Loire Atlantique
Quote:

The 8-71 will be turned slower for the same hp and a little less heat but in your case I would think you would put that $$ into a water injection kit to run on cheaper fuel instead of the bigger blower.




Ok I understand, itīs clear, thanks !

You speak about water injection to run with cheaper fuel ? It's interesting ! Tell me more

I don't know anything about this !

Re: Big block with 6/71 roots project [Re: Filex] #1467564
07/17/13 06:18 PM
07/17/13 06:18 PM
Joined: May 2011
Posts: 4,488
northern,Ohio,USA
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Clanton Offline
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Look at snow performance water injection on the internet.The water and alky cool the intake charge and slow the fuel burn for running less octane.


GOTBOOST!New improved with Victor heads.
http://www.enginelabs.com/mopar-big-bloc...t-of-necessity/
Re: Big block with 6/71 roots project [Re: Clanton] #1467565
07/17/13 07:01 PM
07/17/13 07:01 PM
Joined: Mar 2013
Posts: 13
Loire Atlantique
Filex Offline OP
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Loire Atlantique
Quote:

Look at snow performance water injection on the internet.The water and alky cool the intake charge and slow the fuel burn for running less octane.




I will look that, thank you !


Somebody has a response for my last question ?

-> I want to know if I choose different parts (crank and rods in 440 source and Mahle pistons for exemple) I have to equilibrate the assembly ?
Or it's possible to install the parts (each balanced) without doing anything else ?

Re: Big block with 6/71 roots project [Re: Filex] #1467566
07/17/13 07:36 PM
07/17/13 07:36 PM
Joined: Jan 2003
Posts: 16,376
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dogdays Offline
I Live Here
dogdays  Offline
I Live Here
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Joined: Jan 2003
Posts: 16,376
Unless you buy a "balanced kit" from one source you will ALWAYS have to have the assembly balanced. In the aftermarket world, while 8 pistons may well come in within a gram or two of each other, rods the same way, there is NO standardization of weights between manufacturers. And many manufacturers have different lines of the same parts that have different weights.

So you can see that buying parts from two or three different manufacturers or suppliers, you will need to have the assembly balanced. A previous poster told you where you can do this in the UK.

R.

Re: Big block with 6/71 roots project [Re: Filex] #1467567
07/18/13 01:31 AM
07/18/13 01:31 AM
Joined: Aug 2003
Posts: 43,007
Bend,OR USA
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Cab_Burge Offline
I Win
Cab_Burge  Offline
I Win
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Joined: Aug 2003
Posts: 43,007
Bend,OR USA
Quote:

Quote:

Look at snow performance water injection on the internet.The water and alky cool the intake charge and slow the fuel burn for running less octane.




I will look that, thank you !


Somebody has a response for my last question ?

-> I want to know if I choose different parts (crank and rods in 440 source and Mahle pistons for exemple) I have to equilibrate the assembly ?
Or it's possible to install the parts (each balanced) without doing anything else ?


Balancing engine parts has two seperate operations, balancing all the pistons to the same weight with the wrist pins, same on the rods and then you have to get both ends of the rods the same weight on each end, half the rod is considered rotational weight and and the other half is not Maybe it is consider in some other way I have forgotten about . The crankshaft is spun balanced to the specific "bob weight" that your assembly ends up having, so no ,you can not mix parts and expect them to work well together without having them check for balancing first No sense in taking a chance when using a blower and wanting it to be trouble free. I had treid to make a post several days ago advocating you using a bigger blower than the 6:71, I like and use 10:71 on Mopar V 8 over 440 C.I. You can turn them much slower and build the same amount of boost with a lot lower intake manifold inlet temps. and a lot less parasitic drive loss(HP) by spinning the smaller blower at a higher RPM to get the same amount of boost as the bigger one spinning slower Be careful of what you ask for, you may end up with a real tire burner 600 Hp from a 440 based motor on pump gas is not hard to do with one carburetor, let alone a blower Another thing to consider on a street Roots blower motor is the static mechanical compression ratio, if you set the motor up with 8.5 to 1 comp. ratio and spin the blower at 7% underdrive to make 7 lbs of boost at 6500 RPM and end up with vacume at 4000 RPM and under at part throttle you may be better off increasing the compression ratio to 9.0 or higher up o 9.5 to 1 and spin the blower even slower like 10 % under so it starts to make boost at a higher RPM and still end up with the same amount of HP at 6500 RPM but a lot more torque and throttle responce under 3500 RPM at part throttle Sorry if this seems confusing but there are many different ways to go with a blower, on pump gas less pressure is safer


Mr.Cab Racing and winning with Mopars since 1964. (Old F--t, Huh)
Re: Big block with 6/71 roots project [Re: Cab_Burge] #1467568
07/18/13 11:15 AM
07/18/13 11:15 AM
Joined: May 2011
Posts: 4,488
northern,Ohio,USA
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Clanton Offline
master
Clanton  Offline
master
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Joined: May 2011
Posts: 4,488
northern,Ohio,USA
Don't take whet I said the wrong way Buddy it was just my on MY idea of what he wants without knowing more details.


GOTBOOST!New improved with Victor heads.
http://www.enginelabs.com/mopar-big-bloc...t-of-necessity/
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