pic of a super charged 7.3 idi that's pulling

[dieselgiant]

The m62 will only flow 450cfm at 12000rpm. Your 7.3 will flow that at 4111rpm. It won't even be able to make boost at that rpm. Even if you kept your engine to 3300rpm, you would only be able to make 1psi.

1 is better then nun

 

[FordGuy100]

8.3 whipple, do you have an extra $5k laying around?

For a better explination of the numbers I use.........

457 would be your cubic inches (I am guessing you're going to bore .060), Multiply that by half the rpm you are going to turn which would be 2200. That gives you 1045000 cubic inches per minute. To convert to cfm you divide by 1728 (12x12x12), which gives you 604cfm. If your engine isn't running 100% volumetric efficiency, you need to correct for that. 85% is a pretty standard number for 2 valve engines with no induction work done. That gives you 514cfm@4400rpm. In theory every bar (14.7psi) of boost pressure you have, you will double your flow. In reality, because of rising intake temperatures and added restrictions, the flow will be less than double.

For a better idea use this..........



To convert from pounds of air to cubic feed you need to divide by the weight of air. The weight depends on atmospheric pressure and temperature. At sea level, at 70 degrees F, a cubic foot of air weighs .075lbs at 100 degrees it weighs .069lbs per cu. ft.

I hope that answered your questions.

Also, give this thread a good read.

http://www.oilburners.net/forums/showthread.php?t=45619&highlight=kinda+twin+turbo&page=1

Quick question, in your equation your MAP values you used are 13.7 and 13.5. Arent you supposed to use 14.7psia, which is the rounded off value for normal sea level atm. pressure? Just wondering, otherwise your equations look good, that part just confused me

 

[hairyboxnoogle]

he is using relative AP. IE what the pressure is where he is at probably. about 12.7 here.

 

[hairyboxnoogle]

i have a Q for you smart guys who know your arithmatic, how well would an m92 work on a say. 7.1L spinning to 4400. Not that i necessarily need it to boost that high, but be able to turn that high without it becoming an IED. ATM looking into what it would take to have an electric clutch ran thru a hobbs switch between the turbo and blower. So once the turbo starts building more boost than the blower, it will kill the blower. Theoretically allowing more overdrive on the blower at lower rpms. have the blower goin say 10k rpms at 2300, assuming the turbo is good and kicked in around 2-2200, allowing the blower to NOT spin 20k rpms at 4400 engine rpms.

Some sort of fail safe would be needed i think tho... Imagine losing a boot at 4k and the blower kicking in.... no good beans there.

 

[429idi]

Quick question, in your equation your MAP values you used are 13.7 and 13.5. Arent you supposed to use 14.7psia, which is the rounded off value for normal sea level atm. pressure? Just wondering, otherwise your equations look good, that part just confused me

I pulled that from another thread that I posted that on. If I noticed I would have changed it. I can't remember why I was using -1psi in the first place. I was probably figuring for intake restriction or elevation like hbn said.

 

[blown84]

Thinking out loud here. And not sure if it applies to the smaller blowers, but I do know that a roots style blower requires that fuel is run through it. If you look at the mechanical injection systems on race motors, fuel is injected via intake runners, maybe direct into the cylinder heads, and always on top of the blower. Without fuel flowing through them to act as a lubricant/coolant for the rotors, they will seize. I know this was the case on the blown/alcy motors I used to wrench on, anyone know if the smaller ones (like an Eaton) could suffer the same fate?
Might be worth investigating before the possibility of destroying a super charger.

They didn't run fuel through the detroit blowers. On the engines these eaton blowers were on also just had air running through them.

Maybe it's just a race motor thing....running alcohol through the blower cools it WAY down; enough that the hat and top of the blower will start forming ice on it when warming the motor.

^^ what he said, and exactly. the roots style blowers you were used to were set for big overdrive on motors that pushed 10,000rpm. thats a LOT of heat. so the set up is to keep em from meltin down. it also makes the air more dense. ive seen mild set ups with blow-through style carbs under the blower, and every bolt-on roots style they sell for modern engines, the fuel is delivered way after the blower. at reasonable boost levels, at reasonable rpm, they can be run dry just fine.

Some sort of fail safe would be needed i think tho... Imagine losing a boot at 4k and the blower kicking in.... no good beans there.

MAYBE, it could be set on a relay with a tach with a shift light. set the shift light to come on at the rpm you want the blower to kick out, and when it comes on, it triggers the relay to cut the blower. that way, if you blow a boot, or shell the turbo, the blower wont come back on until youre below the set rpm. just a thought.

EDIT: come to think of it, 85 and later trucks with a manual tranny and the tach option came with shift lights in the top left little light box on the cluster. its amber and says "shift" and perhaps could be adjusted to the rpm you want? i dunno.

 

[hairyboxnoogle]

MAYBE, it could be set on a relay with a tach with a shift light. set the shift light to come on at the rpm you want the blower to kick out, and when it comes on, it triggers the relay to cut the blower. that way, if you blow a boot, or shell the turbo, the blower wont come back on until youre below the set rpm. just a thought.

EDIT: come to think of it, 85 and later trucks with a manual tranny and the tach option came with shift lights in the top left little light box on the cluster. its amber and says "shift" and perhaps could be adjusted to the rpm you want? i dunno.

Thats an idea, i thought about it, but couldnt come up with a way to make it work off of rpms. I did grab my engine out of an 89, but i dont recall any shift light, and my dads 92 doesnt either. As far as i knew, that was a 90s chevy thing. The one benefit to it running off of boost, is no matter what rpm youre at, you always have boost, say the blower is set to kick out at 2200 and youre just cruising at 1800, you either have to down shift, or wait for the turbo to spool.

I did however come up with an alternate idea.

Mount TWO blowers on there, both 90* to each bank and run them with less overdrive, so instead of working 1 so hard and having to have it kick out to keep from overspeeding, have both of them able to turn 12k with the engine at 4400, at the same time, run electric clutches off of boost and no problem. Slightly more parasitic loss at lower rpms, but i would think a cooler air charge compared to the amount of air flowed, and moving more air. But with a potential of drawing 80hp off the fan belt, i think one would need a dedicated 8 rib belt for the super chargers.

One thing for certain, this setup will definately produce enough air. Im going to look up that cfm calculator that was posted and do some playing around. Im thinking 15+ lbs are attainable with 2 m92s. Then a turbo behind them making 35+.

Next question, can the turbo blow through the blowers if they are not turning? Even if it could im seeing it as alot of restriction. Running the turbo to bypass the blowers would require some sort 1-valve to keep from trying to spin the tubo the wrong way and losing boost inside the intake pipes. Disconecting the blower(s) might not be an option period when running a turbo with it. With the bypass setup would need at least two 1 way valves, and the way i have it laid out in my mind, 3 would make it alot easier. Also, my intention of killing the blowers is to free up the horsepower in the top end, roughly 80hp, but with a turbo blowing through them, and them theoretically not having to do anything except turn, i wonder just how much they would draw off the engine anyway, might be able to completely remove the whole blower disconect from the equation.

I know this all sounds pretty far fetched, but with the cost involved (more like the lack of) im really thinking about throwing something like this together, so if you all dont mind, im going to use you guys as my own personal think tank. On the matter of cost, the only thing this would add would be materials for brackets, charge pipe to tie into turbo pipe, a dual cold air instead of single, and the blowers themselves. Oh and lots and lots of time, which i see as a bonus, because i have time to kill. I must say, image of the layout in my mind is pretty epic.

 

[bike-maker]

I'm thinking that trying to force air through the blowers wouldn't work. Even if the turbo had enough pressure on it to spin the rotors in the blower(s), it would give you a major air restriction.

 

[wmoguy]

I can't wait to see youtube videos of someone doing a "budget build" and pushing 35 psi thru an IH IDI.

As for how to actuate a clutch on a charger pulley, why not use a Hobbs switch? Set it to actuate at whatever PSI you want and voila, you have an automated activation/deactivation process for all of about $10

 

[hairyboxnoogle]

As soon as some funds free up, ill pick up a blower, throw the 6.9 on the engine stand and start doing some mock up to see if it will even come close to fitting. And find a place to move the batteries to in order to make room for a dual cold air setup, might be room to set the batteries up and run under them into the fenderwell.

 

[hairyboxnoogle]

I can't wait to see youtube videos of someone doing a "budget build" and pushing 35 psi thru an IH IDI.

Gimme a year or two, and ill send the vid to your email. "budget build" does not mean shortcuts were taken and things were half-assed. The budget aspect would be from picking up things like material for brackets and what not at a scrap yard, getting the blowers used not new, building it myself instead of paying someone. That last one alone will save me probably 15k. Not to mention new blowers are around $2k, when i think i can pick one up for no more than $150 at the JY.

As for how to actuate a clutch on a charger pulley, why not use a Hobbs switch? Set it to actuate at whatever PSI you want and voila, you have an automated activation/deactivation process for all of about $10

99% sure i said use a hobbs switch in a previous post, but yes thats the idea have it set to disengage the blower once the turbo is building 1-2 psi more than the blowers.

 

[wmoguy]

Gimme a year or two, and ill send the vid to your email. "budget build" does not mean shortcuts were taken and things were half-assed.



99% sure i said use a hobbs switch in a previous post, but yes thats the idea have it set to disengage the blower once the turbo is building 1-2 psi more than the blowers.

great, just post up the video here when it's done. I'm sure alot of folks would love to see an IDI hold 35 lbs for more than a few minutes without some serious serious work done to it.

Glad you figured out the hobbs switch idea for yourself.

Excuse my pessimism on the twin super charger idea and other high HP mod ideas. I'd love to see someone actually do it. The candidate for it certainly can't have much desire for fiscal responsibility and needs to have a significant amt of disposable income cuz it will be far from cheap to accomplish and the likelyhood of the IDI holding such boost longevity wise is highly unlikely.

 

[hairyboxnoogle]

great, just post up the video here when it's done. I'm sure alot of folks would love to see an IDI hold 35 lbs for more than a few minutes without some serious serious work done to it.

Glad you figured out the hobbs switch idea for yourself.

Excuse my pessimism on the twin super charger idea and other high HP mod ideas. I'd love to see someone actually do it. The candidate for it certainly can't have much desire for fiscal responsibility and needs to have a significant amt of disposable income cuz it will be far from cheap to accomplish and the likelyhood of the IDI holding such boost longevity wise is highly unlikely.

35lbs of boost at 18:1 compression is hardly any different than 21.5:1 with 10lbs. Therefor wont change reliability / longevity in any amount, in fact after balancing it, its quite possible it would last longer. Twin supercharges isnt for high HP. The idea behind them is low end torque. Basically replacing a small turbo with 2 small blowers. They will only run around 15lbs of boost, but the benefit is constant boost, even if there is only 2-3lbs at idle, there will be 8-10+ at 1200 rpms. As far as "serious" work idk, but there will be signifigant work done. Lots an lots of ARP studs, balancing, blueprinting, align boring and flat decking, some lightening, main girdle, offset ground crank, milled pistons, port work, valve work, heat / cryo treated parts, shot-peening, ect. As of right now the budget stands at $3700 +/- 700, this includes everything except the turbo. And for those that know, that is roughly the price of a reman'd engine from Ford.

But anyway, getting off topic, thats stuff for a build thread, not the blower thread. But dont be suprised if you see a handful of 400+ rwhp IDIs springing up in the next few months / years.

 

[88 Ford]

35lbs of boost at 18:1 compression is hardly any different than 21.5:1 with 10lbs. Therefor wont change reliability / longevity in any amount, in fact after balancing it, its quite possible it would last longer. Twin supercharges isnt for high HP. The idea behind them is low end torque. Basically replacing a small turbo with 2 small blowers. They will only run around 15lbs of boost, but the benefit is constant boost, even if there is only 2-3lbs at idle, there will be 8-10+ at 1200 rpms. As far as "serious" work idk, but there will be signifigant work done. Lots an lots of ARP studs, balancing, blueprinting, align boring and flat decking, some lightening, main girdle, offset ground crank, milled pistons, port work, valve work, heat / cryo treated parts, shot-peening, ect. As of right now the budget stands at $3700 +/- 700, this includes everything except the turbo. And for those that know, that is roughly the price of a reman'd engine from Ford.

But anyway, getting off topic, thats stuff for a build thread, not the blower thread. But dont be suprised if you see a handful of 400+ rwhp IDIs springing up in the next few months / years.

You could get an Eaton m112 for pretty cheap and it would boost a lil quicker than a single m90. It would require less fab work that two m90s and also would be less draw on the engine so you wouldn't have to work on the fan clutch idea. You would just be able to let the SC compound the boost and could get a properly sized turbo for the top end.

 

[seawalkersee]

Couple things: Since EFI, boost has been delivered pre fuel. In fact, I think the early TCs were blow through designs. No matter where you send in the fuel, it will cool down a little. Snow kits are usually after the FI.

Second, little has been done on mine since the last post. I was set to work on it and it started to rain...no good for welding when that happens. I was going to get to it on tuesday but my partner's wife died. I have been taking care of all of the work related stuff for him so he can focus on his kids and other pressing matters at home. Looooong days.

And as far as the blower drive off of the front of the water pump, not a good idea. You can think of the forces to use 10hp on that little shaft and then add to it exponentially by lengthing that with another pully. Go all the way to the crank and find a bigger pully, weld it on and balance it. add an idler and a tensioner to keep the belt from floppin like a naked mans parts in the wind. Much better setup and you will not have to put a new pump on it every other week. Im sure there are other things I forgot, but I have to go.

SWS