[strelkabuilt]

Originally Posted by Tom Vaught

Quote:

If you are doing this for "looks" I would use the larger 8-71 and blow through a dummy 6-71 case that had the pulleu acting like an idler but no rotors inside.

Tom V.

Bill, I agree with Tom on this one. 2 superchargers mean twice as much HP to drive them. The horse power required to turn a TF supercharger is somewhere around 2000 to 3000. Just ask Austin Coil.

[Tom Vaught]

I hold three US patents on A/C Inter-cooling. It works, trouble is you need a BIG Condenser in the front of the radiator to make the thing work properly. You also need a high rpm compressor for the A/C as most a/c compressors are rpm rated pretty low. The "scroll" compressors on the newer Ford trucks have a much higher rpm rating vs the typical a/c compressor.

The reason why I asked about the super chiller vs the carb deal is typically you would never put carbs before an inter-cooler. The inter-cooler tends to pull the fuel out of suspension with the air and you get lean conditions. Lean comditions = backfires and blowers have BIG cavities with fuel that make big explosions. Maybe you have seen the internet video where the guy is tuning his blower engine and pops the blower right off the engine during the video due to a backfire.

Carbed engines with intercoolers typically use turbos or centrifugal superchargers that blow into a inter-cooler and THEN into the carb box or bonnet.

The superchillers I have seen used port injection, either efi or mechanical nozzles.

Tom V.

[Bill Bolin]

Tom, I'm sure you know what you are talking about. I'm not questioning that. Teague Marine which owns SuperChiller sells these for boat applications. http://www.superchiller.com/pages/why.html Most of them are installed on Carburated engines and are located between the intake and the supercharger. I know when they are used in a marine application there is an unlimited supply of cold water which makes a big difference. How do they use them without fuel lean out conditions? It's looking more likely I may have to go with the gutted lower blower but I am trying to understand why this won't work in a non-boosted application. If the car is driven without achieving boost, where would the problem be? I will most likely have this setup for a few weeks to see what happens and then switch to the single blower setup. Who knew it was going to be this big of a PITA.

[Tom Vaught]

Marine engine as you said have a lot of cold water available and they rarely change rpm once they are up on plane. They can be stink fast with the blower and not worry too much about distribution issues.

In your case you are trying to drive the engine on the street with many different modes of operation. I personally think that if you used the second case as a large plenum your distribution might be a lot better. More like the boat deal.

I am not saying that you give up, I am just saying you have to pay attention to stuff. Go for it. Make sure you have at least one burst panel in the intake which I assume you already have as you have been driving the car with the blower for a while now.

Tom V.

[Brian Baker]

Bill...you'll have a 6-71 blowing into an 8-71. How is it that you think you can set it up so it doesn't make any boost? Even if you underdrive both of them, you'll be hard pressed to make less than 6-psi. And that 6-psi will be hotter than if you were making it with a single blower.

If it were me, I'd forego the carbs alltogether, and go injected. Have just enough running through the hat to keep the top blower cool. Have at least 4 more jets between the blowers to keep the bottom one cool. Run your superchiller under that, and then have a nozzle in each intake port to take care of your distribution. To simplify the distribution blocks, you may be able to get away with 4 jets in the hat, 4 between the blowers, and then 8 for your ports. I see no other "practical" way to address the heat and the distribution issues with running both blowers.

[Bill Bolin]

Brian, I'll have the 8-71 feeding the 6-71. I didn't make boost until about 4000 RPM's even with the blower 13% overdriven. If I have the two blowers underdriven (about 20% each) I doubt I would make boost until 3500 RPM's or so. Theoretically, if I keep the car under 3500 RPM's just cruising I would still be making vacuum. I am not going injected just for a one month experiment. Again, with the double blower setup it will be a "Fairgrounds" type car only. After my experiment is done, I will go back to a more traditional blower setup.

[GTOGEORGE]

Normally as soon as you put your foot into the Roots Blower it will make BOOST...................................like ASAP!

[firechicken]

I've decided to go ahead with an intake mounted water/air intercooler on my draw-thru turbo car this year: taking some direction/tips from successful marine installations with these setups.
My intention is to install a coolant bypass valve which will recirculate intercooler water bypassing the charge cooler unless intake pressure goes above atmospheric. The valve will be activated by a hobbs switch or possibly just a nitrous type WOT swich.
This should help alot with the cool low velocity air/fuel charge condensing on the exchanger during non-boost conditions.
Just food for thought on your setup.

[blown 68]

Originally Posted by Pontiac462

Brian, I'll have the 8-71 feeding the 6-71. I didn't make boost until about 4000 RPM's even with the blower 13% overdriven. If I have the two blowers underdriven (about 20% each) I doubt I would make boost until 3500 RPM's or so. Theoretically, if I keep the car under 3500 RPM's just cruising I would still be making vacuum. I am not going injected just for a one month experiment. Again, with the double blower setup it will be a "Fairgrounds" type car only. After my experiment is done, I will go back to a more traditional blower setup.

this is fun ......so bill, it seems on my car,(blown, 3% under) that i make boost not so much at what rpm, but at what throttle blade angle, i can cruise part throttle up to 90 mph, and show little to no boost, but if i nail it bogged in third at twenty mph, i will hit 7psi without hitting 4000rpm, so i don't know if rpm's really work that way or not, just food for thought.
brian.... are you saying if there is 5psi boost, going into another blower, at 5psi boost, there will be 10 psi boost out the bottom? i didn't think it would equate like that, i figure with heat, tolerances, and maybe some wierd scientific mumbo jumbo about putting pressure into something making that same pressure, it wouldn't work that way, but i don't have enough experience. still interesting stuff though! enlighten me at will fellas......

davey

[Brian Baker]

No, I didn't say it would double the boost. What I said was, whatever boost he does make with the double blower will have a hotter output before it hits the chiller, than it would if he were making the same boost with a single blower.

I imagine with both 20% under, it won't make much boost above an idle. I know Bill. "Keeping my foot out of it" is not in his vocabulary (LOL).

[blown 68]

gotcha brian, i wasn't trying to put words in your mouth, i understand your point clearly, when i re-read my post, it sounded kind of funny. i guess my point was, i didn't think that with two blowers stacked, the combined output boost would not be the same as if they were measured seperately. if one put out 5psi, and another put out 5psi, i guess my tired thinking was that if they WERE stacked, the output would be less than 10psi, the individual combined total boost of both. that's not taking the heated charge output of one, into the other, into consideration either. oh, and about the foot thing, i think your dead nuts right on with your thoughts, kinda hard to keep a foot out of all that instant torque.....
davey

[Brian Baker]

I watched Bill once make a nitrous pass at Mason-Dixon with the LeManster. The car pulled the left front wheel 3 feet in the air while the right front wheel barely skimmed the pavement. About 100' out, the car lurched hard to the right and he drove it up into the grass after lifting. He then drove it back up onto the pavement and nailed it, still running a high 10 second pass. That's the Bill I know, and there's no way in hell he's going to keep his foot out of that double-blower setup.

[firechicken]

Actually, you'll end up with more than 10 psi if each blower is pushing 5 psi.
eg. 5 psi is 19.7 absolute (at sea level)
5 psi is more correctly a pressure ratio of 14.7+5 divided by 14.7= 1.34

When this charge is pushed into a second stage at the same 1.34 PR (5psi), you now have 26.4psi absolute at the engine, 11.7psi gauge and a whole lotta heat with 50% efficiencies from roots blowers.

Staging blowers like this is a lot different than just running them in tandem like the ones pictured earlier in the thread

[Bill Bolin]

Originally Posted by Brian Baker

I watched Bill once make a nitrous pass at Mason-Dixon with the LeManster. The car pulled the left front wheel 3 feet in the air while the right front wheel barely skimmed the pavement. About 100' out, the car lurched hard to the right and he drove it up into the grass after lifting. He then drove it back up onto the pavement and nailed it, still running a high 10 second pass. That's the Bill I know, and there's no way in hell he's going to keep his foot out of that double-blower setup.

I remember that pass very well!!!!! It was my favorite pass of that racing season!! I couldn't wipe the smile off my face when I got back to the pits, especially after some spectators were telling me how I sprayed them with grass and dirt while they were in the stands.

Brian, I will be able to keep my foot out of it if it means the diference between not having ring lands on my pistons and keeping them where they belong. There will be plenty of time left in the year for me to put my foot into it after I try my experiment. I will be racing with the Outlaw Pontiacs again this year and I won't be taking it easy on the car.....even with the Kandy paintjob. I didn't build it to baby it and it isn't gonna turn into a trailer queen either!! Only if the show is over 100 miles away will I trailer it. I also intend to join in the Hot Rod Power Tour with it this year for two legs. My temporary insanity will be just that....temporary! If nothing else, I will have a few pictures to put in the scrap book.

[Jack Gifford]

It certainly will draw a crowd!

Once it's done, can I park my "cartoon tractor" next to it?

[Brian Baker]

I'll bet that little tractor pulls some awesome wheelies, Jack.

[Jack Gifford]

All part of the "show" Brian!

[speedshopmike]

bill, really enjoyed yakking the other night on the phone.
looking forward to meeting you sometime.
meant to mention thermal management stuff to you:
thermal barrier coat the valley pan, intake bottom and all passages, the obvious blocking of the exhaust center head holes, thermal coating/wrapping the headers, keep the intercooler water pump isolated from heat, protect the water transfer lines from heat, have a slight restriction relative to the input side on your water exit lines (you want some positive pressure on the push side) - try for 1" feed and 3/4" returns.
also, get a rebuild kit for whatever pump you wind up with as you will need it eventually.
also, i'd runa water temp gauge on teh 'cooler water, just so you can verify it's all working when driving.
later,
mike

[krisr]

After looking through my photos tonight at a show I was last year, I remembered taking a photo of our local guy Gary Myers double blown Mustang close up. I think he took the top blower off for some 'streetability' but was trying to sell it as I saw it on eBay. Here it is!

[speedshopmike]

pretty cool...what motor is that?
hi kris.