Rear End for Forced Induction
Those numbers surprise me. I guess the factory 5.4 is restricted enough to reduce power to only 230 rwhp? I mean, I understand that with proper tuning, air intake, exhaust, and a few other items, you could manage an extra 50-60 horses without the need for forced induction.
So let's say you do those things and move from 230 rwhp to 280 rwhp naturally aspirated. That means when you add the charger, you can manage up to 450 rwhp? From an thermodyanmic stand point, that's a crazy efficient gain. That's an extra 170 rwhp on top of the tuning you already did. That's essentially a 61% gain in power. That seems unusually high. I guess I don't fully understand the proportions of power gain.
So let's say you do those things and move from 230 rwhp to 280 rwhp naturally aspirated. That means when you add the charger, you can manage up to 450 rwhp? From an thermodyanmic stand point, that's a crazy efficient gain. That's an extra 170 rwhp on top of the tuning you already did. That's essentially a 61% gain in power. That seems unusually high. I guess I don't fully understand the proportions of power gain.
Those numbers surprise me. I guess the factory 5.4 is restricted enough to reduce power to only 230 rwhp? I mean, I understand that with proper tuning, air intake, exhaust, and a few other items, you could manage an extra 50-60 horses without the need for forced induction.
So let's say you do those things and move from 230 rwhp to 280 rwhp naturally aspirated. That means when you add the charger, you can manage up to 450 rwhp? From an thermodyanmic stand point, that's a crazy efficient gain. That's an extra 170 rwhp on top of the tuning you already did. That's essentially a 61% gain in power. That seems unusually high. I guess I don't fully understand the proportions of power gain.
So let's say you do those things and move from 230 rwhp to 280 rwhp naturally aspirated. That means when you add the charger, you can manage up to 450 rwhp? From an thermodyanmic stand point, that's a crazy efficient gain. That's an extra 170 rwhp on top of the tuning you already did. That's essentially a 61% gain in power. That seems unusually high. I guess I don't fully understand the proportions of power gain.
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I think I understand a little better now. I was underestimating the amount of boost that would be run. So what kind of rpm range is 10-12 psi at? Sounds like it would be wide open throttle. One thing I've never learned is how you adjust a charger to set a certain psi. (whether it be 8-12, etc.) When someone says they run a certain psi, let's say 10 psi, does that mean the charger is set to only allow up to 10 psi of boost to occur?
I'm sorry for the abrupt thread jack, I can post these questions elsewhere if wanted.
You change PSI by changing pulley size, which in turns spin's the blower faster creating more pressure via the flow restriction of the engine. This is why when someone adds cams, worked over heads, and or exhaust mods to a supercharged engine boost PSI will go down even though the blower is still spinning the same speed. Other factors of the engine can come into play, but the simple answer is spin the blower harder and you will get more PSI.
We normally shift our trucks anywhere from 5200-5400rpm with a max redline of 5600-6000rpm. To keep our factory engines together we want to keep the RPM as low as possible, and only go much past 5200rpm if crossing the traps at the race track etc. Once I personally go built I plan on twisting to 7000+ if the heads/cams will allow it.
We normally shift our trucks anywhere from 5200-5400rpm with a max redline of 5600-6000rpm. To keep our factory engines together we want to keep the RPM as low as possible, and only go much past 5200rpm if crossing the traps at the race track etc. Once I personally go built I plan on twisting to 7000+ if the heads/cams will allow it.
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From: North Canton, Ohio
Maximum boost is normally obtained at WOT. There are several factors that can effect boost such as temperature, humidity, and etc..
Lets say that the design of a blower rates its maximum "boost" at 6 pounds. You can exceed this limit which is refered to most often as "overdriving" by adding a larger pulley to the crankshaft of the engine, or a smaller pulley on the snout, or shaft of the supercharger. Either of these modifications will cause the blower shaft to turn at a higher rpm thus "overdriving" the manufacturers boost numbers. Overdrive boost numbers will depend on the size of whichever aftermarket pulley you choose to install.
(fatherford posted the above response while I was typing this)
Lets say that the design of a blower rates its maximum "boost" at 6 pounds. You can exceed this limit which is refered to most often as "overdriving" by adding a larger pulley to the crankshaft of the engine, or a smaller pulley on the snout, or shaft of the supercharger. Either of these modifications will cause the blower shaft to turn at a higher rpm thus "overdriving" the manufacturers boost numbers. Overdrive boost numbers will depend on the size of whichever aftermarket pulley you choose to install.
(fatherford posted the above response while I was typing this)
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From: North Carolina
No problem this is all we talk about over here lol. With a positive displacement twin screw blower (Whipple, Saleen, Kenne Bell) you can have full boost at 2300rpms if you floor it. Hell you can pretty much have it off idle when flooring it. The other positive displacement blower is an Eaton Roots (Roush, Edlebrock) and will they will build boost based on how quickly they are spun but produce boost very quickly down low providing that off the line grunt and they will usually pull hard till you get close to red line. Some fad a little in higher rpms. Centrifugal blowers (Vortech, Procharger) are similar to a turbo in that they build boost based upon how quickly they are spun. Boost is low at low rpms and full boost is achived in the upper rpm range. A popular way to over come the low boost levels early on is to set the blower up to make a higher amount of boost than needed (say 14psi) and use the wastegate from a turbo to bleed off the excess pressure keeping you at a maximum of 8, 10, or 12psi depending on your wants. Hope this helps. I'd tried to be fair in my explanation to avoid starting any wars.
Psst, the twin screws kick *** from idle to 20psi and you don't need to rig up a waste gate...
Psst, the twin screws kick *** from idle to 20psi and you don't need to rig up a waste gate...
Last edited by twinskrewd; Jan 25, 2011 at 05:15 PM.
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I understand the rate at which they produce power. Positive displacement twin screws produced power by a linear curve, hence why they offer more power at lower rpm. (Normally why they are a better option for trucks) Centrifugal (rotodynamic) chargers produce power by an exponential curve, normally why they're better for higher rpm vehicles (cars).
So when you order a blower kit, do they give you multiple pulley's? Also, I understand that with more air in chamber, there needs to be more fuel to compensate. How do you select the right fuel injector for a blower set up?
So when you order a blower kit, do they give you multiple pulley's? Also, I understand that with more air in chamber, there needs to be more fuel to compensate. How do you select the right fuel injector for a blower set up?
Most superchargers are a full bolt on kit that comes with everything needed. That includes tuning / injectors / blower etc. They only come with 1 size pulley that is set up for the tune that came with it. Being you are a 4.6L I honestly dont know of any blower kits that will work with your truck. I only am aware of 5.4 blowers
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From: North Carolina
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From: Wilmington DE
I didn't even think KB was making them anymore.
There's a guy here looking to get rid of a kit like that.
https://www.f150online.com/forums/su...enne-bell.html
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I just had my truetrc installed yesterday, price of the unit was about what we can find online and install was charged at two hours labor. I did not know how heavy the stocker unit was, I asked for my unit back and when he handed me the box I about dropped the thing.