BENCH RACING: 8-71 V.S. Procharger?

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looking good but dont you want bigger carbs?

Well I was thinking that too but I figured since this is a street car,small cammed 906 headed motor that the 850 may be overkill.I am not putting a cage in this car and will not be racing it a lot (Happy DAd?)so Big Al said the 750's would be the best bet. I hope I wont end up sorry about that choice.

nothing wrong with all that. i have 346 ported heads and did well with .559 lift solid cam
850 carbs and 3%OD got me 8lbs and 10.46/129 ET with no intercooler.i have always ran 110 sunoco to help it be more forgiving.i am sure it could have ran on mid 90's octane with the 34* timing.i ran out of carb at that point though.

Well I have a Scott Brown solid blower grind at .550 lift,dad ported the 906's so I guess I will just have to wait and see. What a learning curve this will be,never had anything quite like this to deal with,but always wanted a blower motor.

Posted By: bigtimeauto

Re: BENCH RACING: 8-71 V.S. Procharger? - 11/08/09 03:20 AM

WOW, tons of misinformation here i'm flattered!

Just buy what you want....... but there is no way a 6 0r 8/71 roots with carbs on gas will drive around a procharger on gas. Now a roots injected on alky well thats a whole different story.(so is that C rotor screw)

My street car:

3150lbs
NO intercooler
cheap Blow thru single 4150 carb
can drive it anywhere, we took it to lunch and a ride today as a matter of fact.
......it still has not made a full power pass yet

Posted By: Quicksilver440

Re: BENCH RACING: 8-71 V.S. Procharger? - 11/08/09 03:31 AM

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WOW, tons of misinformation here i'm flattered!

Just buy what you want....... but there is no way a 6 0r 8/71 roots with carbs on gas will drive around a procharger on gas. Now a roots injected on alky well thats a whole different story.(so is that C rotor screw)

My street car:

3150lbs
NO intercooler
cheap Blow thru single 4150 carb
can drive it anywhere, we took it to lunch and a ride today as a matter of fact.
......it still has not made a full power pass yet

I didn't mean that roots is bettr...I was just questioning the logic of his question.

Big time...how much compression? Race gas? pump? How is drivability with the blow though? I've always wanted to do that....

Posted By: bigtimeauto

Re: BENCH RACING: 8-71 V.S. Procharger? - 11/08/09 03:34 AM

Now on topic:

Roots on the street Pros:
positive displacement
great car show appeal
great WOW appeal driving down the road
cons:
Heavy
needs two carbs or ...
can't see past it with carbs and air filters
can't use a air to air intercooler
is way high and atrracts the wrong kind of attention
can only run low boost on pump fuel because of all of the heat it makes

Procharger on the street pro's:
no hood issues.
only need one 4150 carb
the cops can't see it
builds less heat
lighter than a roots
easier to package
can use your existing intake
intercooling does not impact your vision
can use a air to air intercooler
Cons:
hmmm none i can think of

Posted By: bigtimeauto

Re: BENCH RACING: 8-71 V.S. Procharger? - 11/08/09 03:38 AM

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I didn't mean that roots is bettr...I was just questioning the logic of his question.
Big time...how much compression? Race gas? pump? How is drivability with the blow though? I've always wanted to do that....

9:1
race or pump i adjust accordingly
great driveability (and i'm a DFI guy)
Heads are out of the box indy 440-1

Posted By: Kam*Kuda

Re: BENCH RACING: 8-71 V.S. Procharger? - 11/08/09 03:44 AM

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depends what kinda power you are looking for, with a 540 or 572 you could prly make 1000hp with a small d-series procharger, I personally like all there f-series blowers and would recommend an f-2 just so you have room to grow (since you know you'll want more)

I would agree. Stig Jr made just over 1000 hp with a D1X
The F2 is real nice and efficient design.

I am going to run the D1X on a wedge

Attached picture 5592332-prochargerr.jpg

Attached picture 5592332-prochargerr.jpg

Posted By: blownzoom440

Re: BENCH RACING: 8-71 V.S. Procharger? - 11/08/09 03:55 AM

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Now on topic:

Roots on the street Pros:
positive displacement
great car show appeal
great WOW appeal driving down the road
cons:
Heavy
needs two carbs or ...
can't see past it with carbs and air filters
can't use a air to air intercooler
is way high and atrracts the wrong kind of attention
can only run low boost on pump fuel because of all of the heat it makes

Procharger on the street pro's:
no hood issues.
only need one 4150 carb
the cops can't see it
builds less heat
lighter than a roots
easier to package
can use your existing intake
intercooling does not impact your vision
can use a air to air intercooler
Cons:
hmmm none i can think of

how much does the procharger complete weigh?
you are right i cant see past my blower.
a plus for me is a stock carb[s] will do.not boost referenced[race only]
my blower weighs 70lbs
intercooler 40+5 gall of water 40+lbs

Posted By: moparniac

Re: BENCH RACING: 8-71 V.S. Procharger? - 11/08/09 09:50 AM

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Now on topic:

Roots on the street Pros:
positive displacement
great car show appeal
great WOW appeal driving down the road
cons:
Heavy
needs two carbs or ...
can't see past it with carbs and air filters
can't use a air to air intercooler
is way high and atrracts the wrong kind of attention
can only run low boost on pump fuel because of all of the heat it makes

Procharger on the street pro's:
no hood issues.
only need one 4150 carb
the cops can't see it
builds less heat
lighter than a roots
easier to package
can use your existing intake
intercooling does not impact your vision
can use a air to air intercooler
Cons:
hmmm none i can think of

This is EXACTLY why for me..... Whats funny is some of you guys instantly think of fuel blowers for comparison...

I seen way too many 11-12 second big blower cars and that just not for me is all....

Remember Denny Turza's or whatever his name was that ran Drag Week with the Big Roots Blown camaro.... He was out of competition like 10 miles after starting the event and WON the next year with a pro charger driving 1200 miles

Posted By: Anonymous

Post deleted by Defbob - 11/08/09 12:28 PM

Posted By: David_in_St_Croi

Re: BENCH RACING: 8-71 V.S. Procharger? - 11/08/09 02:12 PM

There is something absolutely feral about a Roots blower sticking up through the bonnet.

Posted By: Kam*Kuda

Re: BENCH RACING: 8-71 V.S. Procharger? - 11/08/09 03:32 PM

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how much does the procharger complete weigh?
you are right i cant see past my blower.
a plus for me is a stock carb[s] will do.not boost referenced[race only]
my blower weighs 70lbs
intercooler 40+5 gall of water 40+lbs

My D1X procharger weights 22.5 lbs but that is without much oil in it,
My intercooler (including BOV) 31x 12 x 3.5 and weights in at 26.5 lbs

About 50lbs all together

Attached picture 5592820-IMG_0571.JPG

Posted By: blownzoom440

Re: BENCH RACING: 8-71 V.S. Procharger? - 11/08/09 03:51 PM

dont forget about the brackets

maybe about 15lbs.
then there is the weight of my rotors to turn and nose,that has got to be 35lbs.you can see some of the packaging advantages.

Posted By: dizuster

Re: BENCH RACING: 8-71 V.S. Procharger? - 11/08/09 06:03 PM

Roots is tough to intercool that's for sure.

Instant throttle response, and low-mid range torque though.

Procharger is down on boost at low-mid range, but a loose converter can usually overcome most of it.

As for reliability, my Dad's small block has had the same used roots, which was bought out of the "for sale" section in the newspaper, since 1985.

They both have their advantages and disadvantages though. It really depends on the application.

To add to the list.

Roots-
Low end torque like you've never felt in your life.

Procharger-
Limited low-mid range boost (which can be a good thing in a small tire car)

Serp. belt problems.
Expensive.

Cost is debatable though depending on power level but...

8-71 will move 2000cfm at 6,000 RPM. 8-71 kits are ~$3700 for blower/intake/pulley's etc. Then +carbs.

2000 cfm is equal to an F1-R? F1-R/F2 kits no intercooler, but with a carb and blowoff valve are around $6,000~$6500 I'm sure I can buy carbs for less then the difference. And at that point you're not intercooled on the pro-charged system anyway, so the gains aren't that huge.

But I agree, for an octane limited gasoline motor, you can't touch a procharger for HP... except with a turbo of course...

Posted By: 67HEMI

Re: BENCH RACING: 8-71 V.S. Procharger? - 11/08/09 06:46 PM

I have built two root style 440's. The first one in '85 had a 6-71 Mooneyham 1 to 1 with teflon strips and two 750's and 8.5 to 1 trw's. The second was in '99 and had a BDS street blower with BDS EFI and bugcatcher injector hat.It had 7.5 to 1 wiseco's and was 10% overdriven. The carb setup with teflon stripped rotors made a lot more power. That motor had stock rods,906 heads that I ported

and a purple shaft cam with stamped steel rockers. In a 4200 pound 69 Coronet 4 speed it ran 10.20 at 135 in 1985.

I said all that to say if you do an 8-71 get the rotors stripped for better clearances and sealing for more boost. The build I am contemplating now is a twin turbo setup for the streeability.

It is hard to beat the looks of a 6-71 with a bug catcher on the street. This was my '65 on the cover of Car Craft January 2000. It wasn't as fast as my first but was way better looking imo.Lost it in a divorce

Posted By: blownzoom440

Re: BENCH RACING: 8-71 V.S. Procharger? - 11/08/09 08:45 PM

my A/W intercooler was 1800$+ pump 3 gall cell and hosses,fittings came to 2200$

Attached picture 5593238-Aug03$06.JPG

Posted By: 67HEMI

Re: BENCH RACING: 8-71 V.S. Procharger? - 11/08/09 11:23 PM

How tall is that? Indy sells their complete polished 8-71 with teflon I think, less carbs and pop off valve for 4650.00

Posted By: blownzoom440

Re: BENCH RACING: 8-71 V.S. Procharger? - 11/08/09 11:47 PM

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How tall is that? Indy sells their complete polished 8-71 with teflon I think, less carbs and pop off valve for 4650.00

the intercooler is 4" and with the blower to the carb base is 11".i got my blower thru a dealer and got a better price,1800 stripped blower polished.[nickerson performance in PA]

Posted By: BEEQUIK

Re: BENCH RACING: 8-71 V.S. Procharger? - 11/09/09 12:34 AM

I got a smokin deal on my blower,intake and throttle linkage (BDS 8-71)and I just bought the carbs from Big Al's toybox.Boost referenced 750's including the spacers and the fuel lines.I am now lacking pushrods and a bunck of the small little trinkets but I'm getting closer.

Attached picture 5593738-IMG_3625.JPG

Posted By: blownzoom440

Re: BENCH RACING: 8-71 V.S. Procharger? - 11/09/09 12:44 AM

looking good but dont you want bigger carbs?

Attached picture 5593772-DSCF7066-1.jpg

Posted By: hemidup

Re: BENCH RACING: 8-71 V.S. Procharger? - 11/09/09 12:48 AM

Procharger gets my vote. I have a 3800 stall converter with 3.92 gears and leave the line at 9 psi of boost. There isn't much lag with that setup. I shift at 6200 rpm and at shift recovery, I'm still at 12 psi.

Posted By: prochargedhemi

Re: BENCH RACING: 8-71 V.S. Procharger? - 11/09/09 12:55 AM

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Instant throttle response, and low-mid range torque though.

Procharger is down on boost at low-mid range, but a loose converter can usually overcome most of it.

Roots-
Low end torque like you've never felt in your life.

Procharger-
Limited low-mid range boost (which can be a good thing in a small tire car)

so you think that a roots style blower comes off idle with maximum boost? Its the same concept a procharger uses, the faster it spins the more air that it passes which in turn creates more boost. I take it you have never riden in a procharged car? I will let you all argue amongst with "all your roots/procharger knowledge"

but at the end of the day boost=force fed (there all the same) different strokes for different folks.

Posted By: blownzoom440

Re: BENCH RACING: 8-71 V.S. Procharger? - 11/09/09 01:05 AM

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Instant throttle response, and low-mid range torque though.

Procharger is down on boost at low-mid range, but a loose converter can usually overcome most of it.

Roots-
Low end torque like you've never felt in your life.

Procharger-
Limited low-mid range boost (which can be a good thing in a small tire car)

so you think that a roots style blower comes off idle with maximum boost? Its the same concept a procharger uses, the faster it spins the more air that it passes which in turn creates more boost. I take it you have never riden in a procharged car? I will let you all argue amongst with "all your roots/procharger knowledge" but at the end of the day boost=force fed (there all the same) different strokes for different folks.

ok maybe you could answer a q.i am at 10% UD with 12 lbs and can got to 30% maybe making 20lbs how does that cpmpare to the procharger %'s? if you can see what i am getting at.

Posted By: prochargedhemi

Re: BENCH RACING: 8-71 V.S. Procharger? - 11/09/09 01:14 AM

i can tell that on my setup a 70 tooth lower and 58 tooth upper "should" make right around 15lbs (it will vary obviously) what ud % is i have no idea how all that works out

Posted By: blownzoom440

Re: BENCH RACING: 8-71 V.S. Procharger? - 11/09/09 01:19 AM

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i can tell that on my setup a 70 tooth lower and 58 tooth upper "should" make right around 15lbs (it will vary obviously) what ud % is i have no idea how all that works out

well with the internal gearing of the charger what is the max rpm?[OD for the charger for your rpm]

Posted By: prochargedhemi

Re: BENCH RACING: 8-71 V.S. Procharger? - 11/09/09 01:41 AM

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i can tell that on my setup a 70 tooth lower and 58 tooth upper "should" make right around 15lbs (it will vary obviously) what ud % is i have no idea how all that works out

well with the internal gearing of the charger what is the max rpm?[OD for the charger for your rpm]

the ratio is 5.4:1 and is rated to spin 65,000 rpm (impeller speed) F-2 procharger

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Not from my experience with a Roots. When I owned my Duster, I could be cruising down the road at 2,500 rpm, stomp the pedal and get max boost, instantly. Same thing from a dead stop and nailing it. A Roots doesn't need rpm to make boost, it needs those throttle blades opened up.

a procharger works the same way, when the throttle blades open the bypass valve closes

Posted By: blownzoom440

Re: BENCH RACING: 8-71 V.S. Procharger? - 11/09/09 01:58 AM

the ratio is 5.4:1 and is rated to spin 65,000 rpm (impeller speed) F-2 procharger

so you can OD that to 58% if you shift at 7,000
i think.i will check the math again.
http://www.google.com/url?q=http://www.p...wvH2ky4NXKqM0Rw

38lbs and 2700cfm

Posted By: blownzoom440

Re: BENCH RACING: 8-71 V.S. Procharger? - 11/09/09 09:05 PM

with the procharger you have a much larger range of use and boost.the roots is more limited.

Posted By: BEEQUIK

Re: BENCH RACING: 8-71 V.S. Procharger? - 11/09/09 09:54 PM

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looking good but dont you want bigger carbs?

Well I was thinking that too but I figured since this is a street car,small cammed 906 headed motor that the 850 may be overkill.I am not putting a cage in this car and will not be racing it a lot (Happy DAd?)so Big Al said the 750's would be the best bet. I hope I wont end up sorry about that choice.

Attached picture 5595440-IMG_3613.JPG

Posted By: hemidup

Re: BENCH RACING: 8-71 V.S. Procharger? - 11/09/09 10:07 PM

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the ratio is 5.4:1 and is rated to spin 65,000 rpm (impeller speed) F-2 procharger

so you can OD that to 58% if you shift at 7,000
i think.i will check the math again.
http://www.google.com/url?q=http://www.p...wvH2ky4NXKqM0Rw

38lbs and 2700cfm

With a F series Procharger, you can get a step up ratio as high as 6.24:1

Posted By: blownzoom440

Re: BENCH RACING: 8-71 V.S. Procharger? - 11/09/09 10:10 PM

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Quote:

looking good but dont you want bigger carbs?

Well I was thinking that too but I figured since this is a street car,small cammed 906 headed motor that the 850 may be overkill.I am not putting a cage in this car and will not be racing it a lot (Happy DAd?)so Big Al said the 750's would be the best bet. I hope I wont end up sorry about that choice.

nothing wrong with all that.

i have 346 ported heads and did well with .559 lift solid cam
850 carbs and 3%OD got me 8lbs and 10.46/129 ET with no intercooler.i have always ran 110 sunoco to help it be more forgiving.i am sure it could have ran on mid 90's octane with the 34* timing.i ran out of carb at that point though.

Posted By: bigtimeauto

Re: BENCH RACING: 8-71 V.S. Procharger? - 11/09/09 10:17 PM

I only run 18* or 24* max if i want to get after it. whats up with that 34*?

Posted By: blownzoom440

Re: BENCH RACING: 8-71 V.S. Procharger? - 11/09/09 10:21 PM

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I only run 18* or 24* max if i want to get after it. whats up with that 34*?

i lost too much HP with less.

Posted By: tilt

Re: BENCH RACING: 8-71 V.S. Procharger? - 11/09/09 10:27 PM

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I only run 18* or 24* max if i want to get after it. whats up with that 34*?

Posted By: ZIPPY

Re: BENCH RACING: 8-71 V.S. Procharger? - 11/09/09 10:28 PM

Roots on e85, anyone?

The ethanol noticeably cools the intake charge, at least my buddys roots case "feels" considerably cooler to the touch...I can't seem to find anyone who knows exactly what the difference is in charge cooling between gas and e85.

Posted By: bigtimeauto

Re: BENCH RACING: 8-71 V.S. Procharger? - 11/09/09 10:33 PM

i would have to believe the e85 will be better than pump gas

Posted By: tilt

Re: BENCH RACING: 8-71 V.S. Procharger? - 11/09/09 10:34 PM

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I only run 18* or 24* max if i want to get after it. whats up with that 34*?

i lost too much HP with less.

What is your initial * and how much do you pull out per pound of boost?

Posted By: bigtimeauto

Re: BENCH RACING: 8-71 V.S. Procharger? - 11/09/09 10:35 PM

me? 36* digital 7

Posted By: 62SAVOY

Re: BENCH RACING: 8-71 V.S. Procharger? - 11/09/09 10:36 PM

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I only run 18* or 24* max if i want to get after it. whats up with that 34*?

Here is what my instructions say that came with it:

Timing: Mechanical advance distributor recommended! 16-22 degrees initial crank timing with total of 32-36 degrees all in by 2500 rpm. These timing recommendations are suggested for a low compression, street driven engine running on premium, 92 octane, leaded or unleaded pump gas.

Posted By: bigtimeauto

Re: BENCH RACING: 8-71 V.S. Procharger? - 11/09/09 10:39 PM

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Quote:

I only run 18* or 24* max if i want to get after it. whats up with that 34*?

Here is what my instructions say that came with it:

Timing: Mechanical advance distributor recommended! 16-22 degrees initial crank timing with total of 32-36 degrees all in by 2500 rpm. These timing recommendations are suggested for a low compression, street driven engine running on premium, 92 octane, leaded or unleaded pump gas.

with boost?

Posted By: tilt

Re: BENCH RACING: 8-71 V.S. Procharger? - 11/09/09 10:41 PM

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me? 36* digital 7

No.. metal storm, just curious is all.
I run 38* initial and have the BS3 pull back to 20* at 15 psi under load.

Posted By: bigtimeauto

Re: BENCH RACING: 8-71 V.S. Procharger? - 11/09/09 10:50 PM

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me? 36* digital 7

.
I run 38* initial and have the BS3 pull back to 20* at 15 psi under load.

thats ok formaking power but for drag racing you need more flexability ie,starting line retard

Posted By: hemidup

Re: BENCH RACING: 8-71 V.S. Procharger? - 11/09/09 10:51 PM

My lastest and best 11.08 pass was with 18*s of timing at wot. No intercooler or aftercooler, just using W/M for now. I'd like to bump the timing to 21*s and put this fat azz truck of mine into the 10's.

Posted By: tilt

Re: BENCH RACING: 8-71 V.S. Procharger? - 11/09/09 10:53 PM

Pulling the power back in essence with digital box for traction.

Posted By: bigtimeauto

Re: BENCH RACING: 8-71 V.S. Procharger? - 11/09/09 10:56 PM

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Pulling the power back in essence with digital box for traction.

correct, i leave on 4* and ramp to the 18* in 2.5 sec.true 10.5 tire

Posted By: tilt

Re: BENCH RACING: 8-71 V.S. Procharger? - 11/09/09 11:00 PM

Quote:

Quote:

Pulling the power back in essence with digital box for traction.

correct, i leave on 4* and ramp to the 18* in 2.5 sec.true 10.5 tire

Hang on for the ride after the 2 sec mark.

Posted By: bigtimeauto

Re: BENCH RACING: 8-71 V.S. Procharger? - 11/09/09 11:14 PM

cool,that and a boost controller and your good. unless thats built in also

Posted By: tilt

Re: BENCH RACING: 8-71 V.S. Procharger? - 11/09/09 11:17 PM

It has that capability just need the solinoids from a Gran National or turbo T/A.

Attached picture 5595649-boost.JPG

Posted By: blownzoom440

Re: BENCH RACING: 8-71 V.S. Procharger? - 11/09/09 11:38 PM

no but i have a 3 step retarder in the box on the shelf.i put the timing at 30* to help the stock main caps live.

Posted By: blownzoom440

Re: BENCH RACING: 8-71 V.S. Procharger? - 11/11/09 01:23 AM

any of you use a A/W intercooler,i need info on a pump for mine.i have a bilg pump and wondered if the rule would work better.[3700gph.]

Posted By: dizuster

Re: BENCH RACING: 8-71 V.S. Procharger? - 11/11/09 10:52 PM

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so you think that a roots style blower comes off idle with maximum boost? It�s the same concept a procharger uses, the faster it spins the more air that it passes which in turn creates more boost.

With a comment like that, you obviously have no idea how either of these blowers work.

They don't make boost the same way at all.

A roots blower is positive displacement, a procharger is not. That means the roots moves the same amount of air, per revolution, regardless of RPM. A 6-71 blower was originally built for a 6 cylinder diesel, with 71 cubic inches per cylinder. 6 x 71 = 426 cubic inches. So when the rotor turns, it captures 426 cubic inches of air, and moves it from the carb to the intake. Small dynamic efficiency differences aside, it moves the same amount of air at 1,000 RPM as it does at 10,000 per revolution. At one to one, take a 340 motor. Every revolution, the motor uses 340 cubic inches of air (at 100% VE), but the blower is providing 426 cubic inches of air. The difference is seen as boost.

A procharger, simply put, is a fan hooked to a belt. Basically, it's no different then your household fan. Low RPM doesn't move much air. And the higher you spin it, the more air it moves.

It's easy to see then how at low RPM, the procharger doesn't make move the air the roots does.

Quote:

I take it you have never ridden in a procharged car?

Roots style do come off idle at instant boost (for the reasons above). Yes I've ridden in several of both roots and procharged cars, and they don't have near the off idle torque that a roots blower car has.

Quote:

I will let you all argue amongst with "all your roots/procharger knowledge" but at the end of the day boost=force fed (there all the same) different strokes for different folks.

They're not "all the same" either. Different blowers/turbos at 15psi will make different power because of the compression efficency. 15psi on a roots won't make the same power as 15psi on a procharger...

I'm not arguing with anyone, just trying to share knowledge and experiences.

Posted By: blownzoom440

Re: BENCH RACING: 8-71 V.S. Procharger? - 11/11/09 11:37 PM

with the unstripped roots having about .010 clearance rotor to case i would think the procharger would be close to the same so when the barings start to go it wont hit the housing.

Posted By: Bakaruda432

Re: BENCH RACING: 8-71 V.S. Procharger? - 11/12/09 09:19 PM

I know they say a Roots blower is at most 50-75% efficient and a Centrifugal is more.

Wouldn't E-85's Ethanol component cool down the air charge as much or more than an air to air intercooler,especially when combined with water injection?

Posted By: blownzoom440

Re: BENCH RACING: 8-71 V.S. Procharger? - 11/13/09 01:13 AM

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I know they say a Roots blower is at most 50-75% efficient and a Centrifugal is more.

Wouldn't E-85's Ethanol component cool down the air charge as much or more than an air to air intercooler,especially when combined with water injection?

the water inj works great.i just dont trust my install of it.that is why i got the intercooler.i tried a snow kit for 3 races though.

BENCH RACING: 8-71 V.S. Procharger?