What CFM do 24 valves flow before boost??

C

CanadianCarGuy

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I am wondering what kind of CFM do 24valves flow before boost? Also would blowing thru a centrifugal supercharger just before the head restrict airflow under full boost enough to affect top end performance? The reason I am asking is because I have been thinking about putting on a large procharger to enhance off idle response and reduce idle and cruise smoke with large injectors. I would have to have a pulley system that spins the procharger 4 times with every engine revolution, at a step up rate of 5.4 that would mean the blower is spinning at 18,000 rpms with the engine idling at 900 rpm. The maximum compressor speed is 74,000 so that would be just shy of 3500 rpm. The F1 procharger makes 38psi boost at maximum speed that might be approximately 9 psi of boost at idle. I think with smarty programming this setup would compliment the S300/S400 twin turbos well. Also I think a very large single turbo with a stainless turbo header and a larger procharger unit would make an pretty wild and original setup. Maybe I am nuts but I can't sleep until I try it! Does anyone think this will work?
 
I would have the supercharger feed the turbo, not the other way around....Unless I have it backwards and having the supercharger "prime" the cylinders with boost at idle would work better....I know RacinDuallie started a thread about this last week though.
 
My reasoning for the supercharger being after the intercooler just before the head is because the blower would help spool the large turbo earlier forcing the engine to make more exhaust and as the turbo spools it would force the blower to speed up which is tied to engine by belt, so it would somewhat force the engine to speed up by the blower belt as well as the boost pressure so you are using the turbo to eliminate the parasitic power loss created by the blower, because the turbo is pushing the compressor of the blower pulling the engine, instead of the engine pulling the belt of the blower. Not sure if this would work in real life, but it sure has me intrigued.
 
CanadianCarGuy said:
I am wondering what kind of CFM do 24valves flow before boost? Also would blowing thru a centrifugal supercharger just before the head restrict airflow under full boost enough to affect top end performance? The reason I am asking is because I have been thinking about putting on a large procharger to enhance off idle response and reduce idle and cruise smoke with large injectors. I would have to have a pulley system that spins the procharger 4 times with every engine revolution, at a step up rate of 5.4 that would mean the blower is spinning at 18,000 rpms with the engine idling at 900 rpm. The maximum compressor speed is 74,000 so that would be just shy of 3500 rpm. The F1 procharger makes 38psi boost at maximum speed that might be approximately 9 psi of boost at idle. I think with smarty programming this setup would compliment the S300/S400 twin turbos well. Also I think a very large single turbo with a stainless turbo header and a larger procharger unit would make an pretty wild and original setup. Maybe I am nuts but I can't sleep until I try it! Does anyone think this will work?
Click to expand...

Under some guidance of an ol guru :bow:who has already done this, I am fitting up one of my roots style 6-71 Blowers to feed the cylinder head plenum. I am looking into hi-helix rotors for this roots blower ( more twist on the rotors). My plan is to adjust the pulley size on the blower to have approximately 6-10 psi at idle. There will be some sort of bypass valve to take restriction of the blower out of the loop once the projected massive twins enter their sweet spot(spoolzone). Neat thing is I can inject various methods of cooling to control egt's. I have been quietly intrigued by this method since word came down the grapevine that this crazy canuk has completed this wildly sick creation...... I am sure- given the adapter I am drawing up, that new custom bent injection lines will be needed. Along with projected double o-rings in the head and double reciever grooves in the block. ARP 625 studs will be tested to their limits as max boost will be reached in very short order. All bottom end hardware will also be ARP's finest.
Complete balancing to the ninth degree along with generous clearances for the rotating assembly.

When I mentioned the projected twin set I thought the guru dropped the phone on the other end:hehe::hehe::hehe:


This diesel engineering thang is entirely intoxicating aint it??:evil:evil With help from this guru:bow: I wanna see where I can take this idea........
 
I am not going with a 6-71 because the seals will blow out running 70psi of boost thru it. I don't have the room for bypass piping and the big honking blower. A centrifical supercharger that compresses air inside itself is much easier to setup and install. I am thinking of a setup for people with large single turbos. I can see blower/turbo combos replacing twin turbos in the near future. Also there are trucks with twin turbos out there that can't supply enough air for the fuel they are putting in, so adding a large blower will make up the difference.
 
CanadianCarGuy said:
I am not going with a 6-71 because the seals will blow out running 70psi of boost thru it.
Click to expand...
The o-ring seals on top and bottom of the case? It doesnt matter- the blower will be bypassed well before 70psi and beyond is reached......
 
I'm debating whether to spin this one off into a new thread. Oh well... :D

The VE would need to be measured by someone without a turbo and a MAF sensor? Or are we close enough with 92% to roughly calculate turbo needs?
 
RacinDuallie,

Here's another thought; instead of bypassing the blower, why not make a custom intake plenum with the blower on top with its own intake and have another intake on the plenum coming in from the side where the existing charge air from the intercooler goes in. One could have a spring mounted flapper valve of somekind that keeps the turbo side blocked off while no boost is present and as boost pressure from the turbo overcomes boost pressure from the blower it opens allowing the charge air from the turbo to enter the plenum. I think as long as the blower is spinning no air can escape out through the 6-71. So instead of bypassing the blower you are using the blower and turbo at the same time. Also with a valve that blocks off the turbo when it quits making boost; it acts as a throttle plate closing so one could have a blow off valve to protect the turbo from barking. Maybe this is exactly what you are doing, but I don't like the idea having both the turbo and blower if you can't use them both at once.
 
I gotta agree with Canadian, If you do not gain some benefit from the 30-50HP the charger is stealing from the crank, it would not be worth it. Can you make a boost activated clutch system to cut out the charger after 25 psi comes from the twins?
 
I think you might see 92% VE at peak torque, somewhere around 1800rpm, but no way you'll see 92% at 3500 rpm. I'd guess more like 85%.
 
Big Blue24 said:
I gotta agree with Canadian, If you do not gain some benefit from the 30-50HP the charger is stealing from the crank, it would not be worth it. Can you make a boost activated clutch system to cut out the charger after 25 psi comes from the twins?
Click to expand...
It's not always about peak HP although a supercharger would take it from the overall HP curve. It should help by moving the HP to a lower, more desirable location on the curve.

Remember 'rev-gain'? :hehe:
 
Keep in mind I know squat about actually doing this, but here is what my spreadsheet pukes out.

Assumed Parameters
CE 70 %
IE 75 %
VE 85 %
Air Filter Diff Press 0.00 psi
IC Diff Press 0.00 psi
Ambient Temp 70 F
Ambient Press 29.9 Inch Hg
RPM 3500
Boost 38 psia

Air Flow
Comp Outlet Temp 403 F
IC Outlet Temp 153 F
Density Ratio 3.1
Pressure Ratio 3.6
Air Flow 998 CFM
Air Flow 74.7 Lb/Min
Air Density 1.1988 kg/m^3
Compressor Hp 237

F1 Procharger
Max Flow (cfm) 1525
Max boost (psi) 38

I am not sure you can't delete all turbos with that model. So I would think just just about any configuration would work, I just don't know how well. I guess you are thinking about running the F1 as the secondary and running a big primary as a set of compounds or vice versa? If I read your post right?

There is also quite a bit of overhead to drive the blower @ 237 compressor Hp. If you adjust the CFM (998) to a lower boost value the compressor Hp would drop. It is just hard for me to predict what the boost would actually be.

FWIW I get:
Assumed Parameters
VE 100 %
Ambient Press 29.9 Inch Hg
RPM 3500
Boost 0 psi

Air Flow
Air Flow 379 CFM
Air Flow 28.4 Lb/Min

Jim
 
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Yes, the blower would be used in the same fashion as the secondary turbo on a twin setup, but has the benefits of making power off idle. I already have twins on my truck, so I am just seeing the blower would clear idle and cruising smoke, while bringing down the twin spool up rpm considerably.
 
CanadianCarGuy said:
Yes, the blower would be used in the same fashion as the secondary turbo on a twin setup, but has the benefits of making power off idle. I already have twins on my truck, so I am just seeing the blower would clear idle and cruising smoke, while bringing down the twin spool up rpm considerably.
Click to expand...

And to add to that, (for us dumber folks)it would allow the use of a much larger than normal Primary (big) turbo. Also could make some previously un-road friendly large singles actually streetable. The mechanics are WAY over my head, but I think I'm fairly able to picture what you guys are wanting to do....



I think it would be sweet....turbo whistle AND that familiar blower whine. :bow:
 
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