Another vote for the Kenne Bell. I like my torque and horsepower instant and linear....and thats something you'll only accomplish with a Positive Displacement blower.
kenne bell or procharger
- Thread starter FOOT2DFLOOR
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the heat is very significant. Find someone with a supercharged vehicle and touch there supercharger after they have been driving around or made a pass at the track. you can't touch it without burning your self. I would not be surprised if you see intake temperatures at 175 degrees while driving around. it would be even higher if you were racing it and beating on it. You're asking for a lot of trouble if you put that kenne bell on without an intercooler
for a street car i'd say a KB would be a good choice.
sure the no intercooler is a drawback but i wouldnt be super worried about that unless your running alot of boost.
if you have the PC or vortech, pullied for 10 psi of boost at redline, your going to PEAK 10 psi, so what happens is you WONT have that much boost in the midrange, which IMO is what gets a car moving.
with the PD style blower, pullied for 10 psi means 10 PSI ALL THE TIME, more or less its just an amplification of your current powerband. at lower rpms and int he midrange, your going to have that 10 psi of boost instatly, instead of having to tach the car to higher rpms to get the higher boost beacuse the midrange you only see half that
granted the centrifugal compressor is more efficient, its just all about how much power your going to make and what you want from the car. if going to an all out balls the wall drag oriented car, thats only going to see higher rpms at the track, the centri blower would be awesome. but for a street car that is going to be driven around alot. the instant torque from the full boost at will is great.
i myself ran a vortech, while the power it made was KILLER on the top end, i felt the lower and midrange wasnt much more than N/A, dont get me wrong the vortech rocked and made alot of power, but since my car is mostly cruised on the street, i wanted more pull in the midrange. so i'm fixing to do a turbo setup, to me a turbo is sort of the best of both worlds, has more boost down lower (assuming its matched up right) and has the good effieciency of the centri style blower. plus i have always wanted to do a turbo setup, but the roots would even come in sooner than a turbo.
if you all that worried about inlet temps, you could run some meth injection. but i dont see what you shouldnt be able to pull off 10 psi without a problem. you could even make the tune a hair extra rich and keep the timing conserative to give yourself a cushion.
boost down low FTW
but honestly either way it will help out a ton and run like a scalded ape with either the KB or PC
sure the no intercooler is a drawback but i wouldnt be super worried about that unless your running alot of boost.
if you have the PC or vortech, pullied for 10 psi of boost at redline, your going to PEAK 10 psi, so what happens is you WONT have that much boost in the midrange, which IMO is what gets a car moving.
with the PD style blower, pullied for 10 psi means 10 PSI ALL THE TIME, more or less its just an amplification of your current powerband. at lower rpms and int he midrange, your going to have that 10 psi of boost instatly, instead of having to tach the car to higher rpms to get the higher boost beacuse the midrange you only see half that
granted the centrifugal compressor is more efficient, its just all about how much power your going to make and what you want from the car. if going to an all out balls the wall drag oriented car, thats only going to see higher rpms at the track, the centri blower would be awesome. but for a street car that is going to be driven around alot. the instant torque from the full boost at will is great.
i myself ran a vortech, while the power it made was KILLER on the top end, i felt the lower and midrange wasnt much more than N/A, dont get me wrong the vortech rocked and made alot of power, but since my car is mostly cruised on the street, i wanted more pull in the midrange. so i'm fixing to do a turbo setup, to me a turbo is sort of the best of both worlds, has more boost down lower (assuming its matched up right) and has the good effieciency of the centri style blower. plus i have always wanted to do a turbo setup, but the roots would even come in sooner than a turbo.
if you all that worried about inlet temps, you could run some meth injection. but i dont see what you shouldnt be able to pull off 10 psi without a problem. you could even make the tune a hair extra rich and keep the timing conserative to give yourself a cushion.
boost down low FTW
but honestly either way it will help out a ton and run like a scalded ape with either the KB or PC
Big deal, you could see 175-degree intake temperatures on a N/A intake on a hot day as well. Intake temperatures and discharge temperatures aren't the same thing. Running around under vacuum, a KB shouldn't run any more than 15-30 deg above ambient. He might see 180-deg at WOT, but even then that's not horrible. I've seen guys crack 230-deg with overpullied Eaton’s without hurting a thing. As long as timing curves are on the conservative side and fuel curves are generous, he shouldn't need to worry.
The whole "you'll pop your engine with a Kenne Bell" myth is total bunk. The number one thing to consider is not to trust the out of the box set up. Especially with an FMU. Get it to the dyno and verify everything is on the up and up. FMU’s are band-aids and should be considered a ball park guess at best.
If you add a water/meth kit, you will drop outlet temps by about 60 or so degrees, maybe more, maybe less depending on the combo and how much water/meth you spray. If your willing to do some custom fab work, or have someone do it for you , you can add a intercooler to a 5.0 based engine. My friend did it to his 331 based 5.0 and with a 2.2L Kenne Bell, he is seeing 18 psi after intercooler. Of course this is not a stock block. He is using a FRP race block. But he sees (with the old combo) 550whp and over 600 lb/ft wtrq. The torque curve is SICK! over 500 lb/ft wtrq from 2400 rpm thru 5,800 rpm, peaking at 615 wtrq at 5,200 rpm or so.And he also uses a water/meth injection with the air to water intercooler. I will admit that it took a LOT of custom fab work to pull off.
15-30 degress above ambient while cruising??? that would be with an intercooler. I see almost 150 degrees with my whipple while idling in the driveway with 70 degree ambient temps. and i am refereing to temps under the s/c after the air has been compressed. You can't compare this to a n/a motor because forced induction changes everything.
150 degree's at idle?!?!?! Where are you taking your ACT readings from? Even with the nature of the Twin Screw (compressing air all of the time), those reading are way out side of normal of any I've seen. Are you reading the actual charge temperatures taken at the discharge port, or the heat sink of the manifold temperatures themselves?
the temp is taken out of one of the intake runners, this is on my fully built lightning with a whipple 3.4. this is also a common idle temp when sitting still as i have researched with a lot of lightning guys. when you go wot, the computer is set to pull timing at 150 degrees to offset the gain in temps and in an effort to avoid detonation. which is why i don't think the kb would we worth it without an intercooler. you wouldn't be able to run the boost or timing that you could if you were running it through an intercooler and cooling the downstream air temps (under the s/c)
Ahhh, that was my next question...."how big is your Twin Screw?" Large Twin Screw blowers as you probably know are horribly inefficient at lower blower RPM. As a matter of fact, that big 3.4L of yours is quite frankly probably putting out the same discharge temps at idle as it is at 10-15psi. From what I recall, they aren't seeing peek adiabatic efficiency until upwards of 20psi.
So yes....I agree with you in the sense that I wouldn’t recommend running a great big unit like that without a cooler.
But then the KB unit isn't running that much blower. The general rule, is the smaller the blower, the sooner the adiabatic efficiency is reached and at lower blower speeds. The 2.1L is considered medium at best by today’s standards and since there’s so much less surface area to it compared to the 3.4L because of the sheer difference in displacement, compounded with the fact that the rotors themselves have a shorter seal length by comparison, I would bet that the idle discharge temps won’t exceed much more than 80-90-degrees on average….probably up around 100-deg on a hot summers day.
They do however throw more heat down low than your average Eaton M90 or M112 (since again, the nature of the Twin Screw is to "compress" the air...all of the time, even when under vacuum when its not required), but they usually start coming into their efficiency ranges at around 6psi and peek around 11-13psi from what I recal.
Still not as cool or clean as an they would be running through an intercooler, but not exactly unmanageable either. Especially with some higher octane fuel as a cushion.
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