pic of a super charged 7.3 idi that's pulling

[blown84]

429idi, how should i set up a 7.5L motor with an 8.3L whipple blower? goal is 6psi at idle. 8-9 at 1200, peak no more than maybe 12. IP will have a gm rev-limiter (4400 rpm that i plan to use all of, on a semi-regular basis).

 

[towcat]

does anyone know if the intake has to be thru the back on one of these m90's.. or could one be rigged to have the intake thru the top where the intercooler plenium bolts on??

these blowers draw through the back and exit underneath.
the below pics are the m112 version. they have the largest displacement of this design. the smaller output ones have a smaller outlet. then air/water intercooler is directly beneath the output on the first pic.

 

[88 Ford]

That is a cool setup and I like the intercooler setup. Its a good way to cool the boost.

 

[dieselgiant]

Just picked up a m90 off a GM 3.8 for $60 now the gears a starting to turn.
http://i1225.photobucket.com/albums/ee399/MGehmanf250/Supercharging/IMGP0532.jpg

Here's how it will sit.
http://i1225.photobucket.com/albums/ee399/MGehmanf250/Supercharging/IMGP0537.jpg

Thinking off a serpbelt pulley driven off the water pump pulley. For this pic just imagine the serpbelt pulley mounted in front of the vbelt pulley and a spring tensioner somewhere in between.
http://i1225.photobucket.com/albums/ee399/MGehmanf250/Supercharging/IMGP0542.jpg

Here's the whole album
http://s1225.photobucket.com/albums/ee399/MGehmanf250/Supercharging/

 

[dieselgiant]

The m90's flow 520cfm at 12000rpm. The serpentine crank pulley is 7", I will be using a 1.929 pulley which puts me at 11974rpm blower speed at 3300rpm engine speed.

my 429 (bored .040 over) at 3300rpm, at 85% VE will flow 340cfm.

520/340=1.529x14.7=22.48psia-14.7=7.78psi boost pressure. This doesn't figure in temperature increase, but it will give you an idea. I can post later if you really want to know how to figure it out.

The thunderbirds ran 12psi stock, power peaked at 4600rpm, and red line was 5300-5500.

3.8
232x2750=638000/1728=369.2x.85=313.8cfm

6.9
420x1650=693000/1728=401x.85=340.8cfm

7.3
445x1650=734250/1728=424x.85=361cfm

I'd like more info on the cfm calculations. I'm confused more about the numbers.

 

[429idi]

429idi, how should i set up a 7.5L motor with an 8.3L whipple blower? goal is 6psi at idle. 8-9 at 1200, peak no more than maybe 12. IP will have a gm rev-limiter (4400 rpm that i plan to use all of, on a semi-regular basis).

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..........

Here is the equation I use when choosing a turbo.


Wa= (MAP x VD x N/2 x VE) / (R x (460+Tm))

· Wa = Airflowactual (lb/min)
· MAP = Manifold Absolute Pressure (psia) =
· R = Gas Constant = 639.6
· Tm = Intake Manifold Temperature (degrees F) =
· VE = Volumetric Efficiency =
· N = Engine speed (RPM) =
· Vd = engine displacement in Cubic Inches

Lets say you wanted to run 15psi of boost at 3300rpm, intercooled, with 85% ve, on a 7.3 (444cid engine).

so,

wa= ((13.7+15) x 444 x (3300/2) x .85) / ( 639.6 x (460+130)) = 47.4lbs/min at a p/r of 2.09.


For 20 psi

wa=((13.5+20) x 444 x (3300/2) x .85) / (639.6 x (460+130))= 55.6lbs/min at 2.45 p/r



for 30psi boost

wa= ((13.7+30) x 444 x (3300/2) x .85) / (639.6 x (460+130))= 72lbs/min at a 3.18 p/r

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

 

[CaptTom]

ALREADY A FACTORY DONE DEAL!!!

....except it wasn't Ford who did it.

For awhile, the Vikings made an engine that had both sc and turbo installation.

Volvo made a boat engine with this very application because on boats, we have to dig our way out of a hole before getting our craft up to cruise.

The SC pulled us out of the hole in no time and shut off electrically once the engine started spooling up the turbo. There was a cross-over point when the turbo totally took over.....yes, around 12-1500- depending on throttle position, engine load etc.

There are plenty of 12V electric clutches that you can install on the front of whatever SC you choose. The dilemma will be to find the sweet spot for shut off for the application chosen. I could see where a tow vehicle could benefit greatly from the combo set-up or a snow plow with an SC only.

I'm not sure where the electric would hook in for automatic shut off, on the Volvo, the computer controlled the SC. With an all mechanical engine, I'm not sure where to plug in to, but there might be some type of turbo boost switch that could turn off the SC for mechanical simplicity.

BTW- Volvo stopped making the combo, not because it was a poor performer, but the fishermen who were trolling found out that the sweet spot was right smack dab in the middle of the power transfer between the two. It carboned up the engines pretty badly, and it also made for a surgieness because a boat never runs on a flat surface, always climbing and coasting up-n-down swells. Neither the engine or driver could figure out where the throttle should be. The fishers disconnected the SC's clutches with a manual switch, but voided warranties. Also, the fishers would load up the fuel system and really make carbon when the SC was manually turned off. The low end was lacking sufficient air for the injectors at low end.

When used as a ski boat.... no problems, always trying to get up to speed with heavy throttle, system worked as flawless as anything.

I'm a newbie IDI owner, so can't even guess where to start plugging in. I'm sure the smarties around here could figure out the system pretty easily. The mounting and getting it to work isn't the problem, it's balancing the fuel with the air for maximum performance.

Just a little different insight.

 

[dieselgiant]

Awesome write up. Figured out that I have a m62 instead but with how I plan on running it I should have 12000rpm at WOT which is 4200rpm. Maybe I should move that down to a more useable rang though.

 

[hairyboxnoogle]

Do the 3.8 GMs have a water to air cooler under them factory?

 

[429idi]

Awesome write up. Figured out that I have a m62 instead but with how I plan on running it I should have 12000rpm at WOT which is 4200rpm. Maybe I should move that down to a more useable rang though.

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.

Are you sure it's a 62? It looks like a 90.

Here are the dimensions if you haven't found them already.

http://www.eaton.com/Eaton/Products...utomotiveAftermarket/Superchargers/PCT_221788


I don't think the gm's use intercoolers, that's why those guys can't run has high of boost numbers as the tbirds. At least the older ones anyways.

 

[hairyboxnoogle]

I don't think the gm's use intercoolers, that's why those guys can't run has high of boost numbers as the tbirds. At least the older ones anyways.

So the t-birds did? hmm, i doubt my chances of finding one are all that great, until now i dont think i had heard of a blown 3.8. I assume this was a SHO option?

 

[bike-maker]

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.

 

[429idi]

So the t-birds did? hmm, i doubt my chances of finding one are all that great, until now i dont think i had heard of a blown 3.8. I assume this was a SHO option?

The tbirds had external air/air intercoolers and piping.

http://cgi.ebay.com/ebaymotors/3-8L...r_Truck_Parts_Accessories&hash=item4cf9fc3030

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.

 

[bike-maker]

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

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.

 

[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.

Are you sure it's a 62? It looks like a 90.

Here are the dimensions if you haven't found them already.

http://www.eaton.com/Eaton/Products...utomotiveAftermarket/Superchargers/PCT_221788


I don't think the gm's use intercoolers, that's why those guys can't run has high of boost numbers as the tbirds. At least the older ones anyways.

It came out of a 1995 Riviera they had m62's on them and it has a short snout, the m90's had a long snout and were used in 1996+ 3.8L SC.