supercharger question
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....it's pointless for it to go on any further. Just agree to disagree fellas and STFU!mogs01gt said:
Where does horsepower come from? It comes from torque and rpms.
If you take the same car (same, gears, engine type etc.) and put a 6 psi twin screw or a 6 psi centrifugal, the twin screw makes more power early, which will make it accelerate early. And what facts have you pointed out. You say, this car with gears, the article states. These are not facts, these are your own personal facts that you have justified in your mind. Think about what you are saying. The car that makes boost (power) later will win a race, it just doesn't add up. If we were to race 1/8 mile, 1/4 mile, or cross country, having the torque down low (horse power down low) it only makes sense who would win. Now when you start to say that changing gears in the centri and then race, well then we are comparing two different cars. I make 6 psi at 2000 rpms, I have read countless forums (not facts, facts are results from a controlled study, not my buddy said) about guys having the rev limiter set higher (I think it might be in this thread of moving it to 6800 rpms, again another modification to the car, not the same car) to get full boost or a little more. I have 6 psi from 2000 - 6000 (or until I blow it up), positive displacement works different than centrifugal, it does not depend on rpms ( after 2000) to make boost. I don't trackl my car, it is a daily driver and I love feeling the power at all rpms (even at 1000 I can see 3 psi, you can't say that about your 6 psi centri kit). In the end, your argument just doesn't make sense, and be careful what you call facts.
WhiteDevil69
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If it will end this useless debate then your right mogs... torque isn't important for acceleration.... Thats why supras with 1000hp are running 12's... Unsubscribing, waste of time, thickest head I have ever encountered. 
P.S. I will give it to yah though, you never give up..
P.S. I will give it to yah though, you never give up..
No, now you are trying to change what I am saying to fit your side. This entire thread was about which type performs better. Not one person has brought up anything that makes a positive displacement blower, like a Kenne bell, out perform a Centrifugal. Everyone is saying, take the gears out, same boost blah blah blah. If you guys really want me to find more articles and websites that say the same thing about a high peak torque compared to a lower peak torque is better for accleration, fine I will. I know there are a lot out there. I have read them.Then you people will try and make the same arguments about gears,same power levels or blah blah. When you race a car, you build it to what you have. Last time I checked, people do not just slap on parts that do not help performance when they want performance.mrpositraction said:Where does horsepower come from? It comes from torque and rpms.
If you take the same car (same, gears, engine type etc.) and put a 6 psi twin screw or a 6 psi centrifugal, the twin screw makes more power early, which will make it accelerate early. And what facts have you pointed out. You say, this car with gears, the article states. These are not facts, these are your own personal facts that you have justified in your mind. Think about what you are saying. The car that makes boost (power) later will win a race, it just doesn't add up. If we were to race 1/8 mile, 1/4 mile, or cross country, having the torque down low (horse power down low) it only makes sense who would win. Now when you start to say that changing gears in the centri and then race, well then we are comparing two different cars. I make 6 psi at 2000 rpms, I have read countless forums (not facts, facts are results from a controlled study, not my buddy said) about guys having the rev limiter set higher (I think it might be in this thread of moving it to 6800 rpms, again another modification to the car, not the same car) to get full boost or a little more. I have 6 psi from 2000 - 6000 (or until I blow it up), positive displacement works different than centrifugal, it does not depend on rpms ( after 2000) to make boost. I don't trackl my car, it is a daily driver and I love feeling the power at all rpms (even at 1000 I can see 3 psi, you can't say that about your 6 psi centri kit). In the end, your argument just doesn't make sense, and be careful what you call facts.
Find me some modulars SOHC with a Kenne Bell that is running 9s or 10s.
supras now?? What does supras have to do with a Modular mustang with forced induction??WhiteDevil69 said:If it will end this useless debate then your right mogs... torque isn't important for acceleration.... Thats why supras with 1000hp are running 12's... Unsubscribing, waste of time, thickest head I have ever encountered.
P.S. I will give it to yah though, you never give up..
Laser-01-gt
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mogs01gt said:
mogs, please, i idont want to argue with you, but you are not understanding what people are saying. i never said one blower was better then another, all i said was that at lower boost levels a positive displacement will be quicker then a centrifigal. but, and this is a big but, at higher boost level the efficiency of a centrigal will win out.
as for the article that you supplied, it clearly states that "engine a cant rev as fast as engine b" here is a part of it below
Armed with this knowledge, let’s take an example. Engine A generates a maximum torque of 100 ft.-lbs. at 3,000 RPM. Engine B also generates a maximum torque of 100 ft.-lbs., but it happens at 6,000 RPM. Which engine would you put in your race car?
Many people would take engine A, reasoning that its torque is more "accessible" since it doesn't have to rev as high. However, engine B is far better. It revs twice as high as A but gets the same torque. So engine B can use gear ratios that are twice as short without sacrificing speed. Since the wheel torque is equal to crankshaft torque multiplied by the gear ratio, engine B can produce twice as much torque at the wheel of the car. Yes, that means twice the acceleration.
Now I'm sure many of you are asking, "why not put those same short gears in engine A?" You can; but it limits your speed because engine A can't rev as high. You'll only be able to go half as fast in any given gear. And every time you shift up to the next gear, you're losing acceleration because you're getting less torque at the wheel of the car. For example, if you both start out in 1st gear you will be racing head-to-head. But soon, say around 20 mph, you have to shift to 2nd. But your competitor, using engine B, can stay in 1st gear until 40 MPH (since you both have the same gear ratios but he can rev twice as high). So you begin to fall behind and your competitor blows by you. In fact, he's got twice the overall acceleration you have.
Many people would take engine A, reasoning that its torque is more "accessible" since it doesn't have to rev as high. However, engine B is far better. It revs twice as high as A but gets the same torque. So engine B can use gear ratios that are twice as short without sacrificing speed. Since the wheel torque is equal to crankshaft torque multiplied by the gear ratio, engine B can produce twice as much torque at the wheel of the car. Yes, that means twice the acceleration.
Now I'm sure many of you are asking, "why not put those same short gears in engine A?" You can; but it limits your speed because engine A can't rev as high. You'll only be able to go half as fast in any given gear. And every time you shift up to the next gear, you're losing acceleration because you're getting less torque at the wheel of the car. For example, if you both start out in 1st gear you will be racing head-to-head. But soon, say around 20 mph, you have to shift to 2nd. But your competitor, using engine B, can stay in 1st gear until 40 MPH (since you both have the same gear ratios but he can rev twice as high). So you begin to fall behind and your competitor blows by you. In fact, he's got twice the overall acceleration you have.
but contrary to your article, whether you have a positive displacement or not, we all have the same amount of revs available. unless your car, like the example you gave us, can rev twice as high with a centrifigal, then we all have the ability to run the same gears.
another way to look at it would be like this. we have a stock motor, that makes a 250ft/lbs of torque from 2500rpm to 6000rpm, very flat torque curve. that equals 285Hp@6000 rpm peak power. but at 3000rpm, we are only making 142hp.
if we add a centrifigal blower at a peak of 7#'s of boost. that would 375ft/lbs at peak boost, around 6000rpm, wich equals 428hp. very nice gain, but at 3000rpm we are only making 3.5psi (centrigals are based on engine speed) so at 3000 rpm we make 312ft/lbs wich is 178hp. at 4500rpm we should be making around 5#'s of boost wich would equal 343ftlbs and 294hp.
if we add a positive displacment blower, it would be 7# the whole range. so at 6000rpm we would make the same 375ft/lbs and 428hp, but at 3000 we would also make 375ft/lbs and 214hp, over 35 more hp then the last example.
at 4500rpm we still make 375ft/lbs and 321hp, an advantage of over 25hp.
the reason centrifigals are better at the track, has to do with efficiency at higher boost levels. once you start going crazy with the boost, the positive displacment blower have a tougher time, but at lower boost levels they have a distict advantage. they even make a kit now to put a centrifigal blower in place of the eaton on the cobra. i beleive i saw it making 700hp or something like that, at those numbers the efficiency of the centrifigal is a huge advantage. then you can bring the argument of a turbocharger, wich has the efficiency of a centrifigal, the low rpm bosst of a positive displacement, but suffers from heat and turbo lag. none are better, just depend on what your needs are.
WhiteDevil69
New Member
This is why I brought up the supra's. You cant make statements like this and not expect someone to correct you... this just doesn't make any sense, I mean, do you really believe this?mogs01gt said:
the slow reving part was referring to the shorter gears. Not comparing the motor without gears to each other.
Not sure where you get this 3.5psi at 3k. Most Centrifugal blown cars I have seen, reach peak boost levels between 3k and 3.5k rpm. Not 3.5psi.
My friends stock lt1(has a catback), whom I usually race at the track because he cant drive. will see 6psi, max boost, at around 3k at WOT. PSI is also a measurement of pressure, without a device to measure the actual air flow, I cant comment on which type will flow more air into the motor at a comparable psi.
Turbo's is a whole other discussion.
Not sure where you get this 3.5psi at 3k. Most Centrifugal blown cars I have seen, reach peak boost levels between 3k and 3.5k rpm. Not 3.5psi.
My friends stock lt1(has a catback), whom I usually race at the track because he cant drive. will see 6psi, max boost, at around 3k at WOT. PSI is also a measurement of pressure, without a device to measure the actual air flow, I cant comment on which type will flow more air into the motor at a comparable psi.
Turbo's is a whole other discussion.
My point was, motors do not need to make peak torque at a low RPM to have accerlation.WhiteDevil69 said:This is why I brought up the supra's. You cant make statements like this and not expect someone to correct you... this just doesn't make any sense, I mean, do you really believe this?
oh my God) THUNDERBIRD! 
Laser-01-gt
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mogs01gt said:
i have resarched this topic to death, and have found that a 6psi centrifugal blower will not make peak boost at 3000rpm. they dont work that way. i dont care what youe meter tells you. if it is geared to make 6psi peak, then it is not making full boost at half speed.
and no, slow reving means one engine has a lower rpm then another, otherwise you could shift at the same time. he states that very clearly.
if engine A makes 100ftlbs at 6000rpm and engine B makes 100ftlbs at 3000 and 6000rpm, then engine B will be quicker. there is no way to state it more clearly.
you assume that a positive displacement blower with its low and mid rang torque will loose out to high rpm power of a centrifugal, but fail to realize the a PD blower also makes the same high rpm power as a centrifugal blower.
Laser-01-gt
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i found this in test done in super fords magazine comparing a KB to a procharger and a vortech. it is on the web
all 8psi kits
charger Vortech Procharger
2500 1.7psi 1.9psi
3000 2.3psi 2.7psi
3500 3.1psi 3.7psi
4000 4.0psi 4.6psi
4500 5.2psi 5.7psi
5000 6.2psi 6.9psi
5500 6.8psi 6.8psi
6000 7.6psi 7.6psi
vs a KB kit that will make its 8lbs from 2000rpm to redline.
ps. if you look at the dyno of a KB motor, peak power is a redline, or close to it.
all 8psi kits
charger Vortech Procharger
2500 1.7psi 1.9psi
3000 2.3psi 2.7psi
3500 3.1psi 3.7psi
4000 4.0psi 4.6psi
4500 5.2psi 5.7psi
5000 6.2psi 6.9psi
5500 6.8psi 6.8psi
6000 7.6psi 7.6psi
vs a KB kit that will make its 8lbs from 2000rpm to redline.
ps. if you look at the dyno of a KB motor, peak power is a redline, or close to it.
I was just going to use that example….mogs01gt said:
Mike Siska runs a ’95 Thunderbird (and that comes with IRS rear suspension for those that didn't know) that weighs in at over 3920lbs with him in it. If memory serves he's got ported PI heads, 4.10 gears, full exhaust and a 2400 stall in a built 4R70W.
He runs 10.90@125+mph on 12psi. The charger is an intercooled Lysholm 2300AX twin screw (similar to that of a KB) and make around 500-525rwhp. (edit: had to clean up the stats a bit.)
You can actually see his car in one of the October issue of MM&FF in the Luxobarge shoot out.
Tell me Mogs, given all things equal....would you still think that a centi would outrun a positive displacement blown car? Say 6psi (Centrifugal blower of your choice) VS. A 6psi KB Car. No gear changes, no weight reduction, nothing at all different.....both running D/R's, who's got the advantage?
mogs01gt said:
From the TCCoa web site:
Yes, Mike Siska's 1995 AED T-Bird ran 10.90 @ 125.5 mph in Ohio. You can make serious power with these kits, it just depends on how serious your budget is. Mike is currently making 500 RWHP with the AED whipplecharger blower
Hey you asked for it Dumba** Being a newb has nothing to do with the ability to research and comprehend. Do you think that because you have over 2000 posts that you aren't a newb? Your comments and lack of presented evidence relevant to this subject matter prove otherwise.
Gearbanger 101 said:I was just going to use that example….
Mike Siska runs a ’95 Thunderbird that weighs in at over 4100lbs with him in it. If memory serves he's got ported PI heads, 4.10 gears, full exhaust and a 3200 stall in a built 4R70W.
He runs 10.90@128mph on 12psi. The charger is an intercooled Lysholm 2300AX twin screw (similar to that of a KB) and make around 525-550rwhp.
You can actually see his car in one of the last couple of issues in MM&FF in the Luxobarge shoot out.
Given all things equal mogs....would you still think that a centi would outrun a positive displacement blown car? Say 6psi (Centrifugal blower of your choice) VS. A 6psi KB Car. No gear changes, no weight reduction, nothing at all different.....both running D/R's, who's got the advantage?
Bout time you showed up. I think this is over though....besides the guy is brain dead.
Laser-01-gt
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http://mustang50magazine.com/techarticles/138_0404_open_dyno_s.jpg
http://www.kennebell.net/media/articles/2_SCREW.pdf
here are links to 2 different magazines testing 2 different 4.6. I know it is hard to figure out, but please look close at it all.
link one shows a Mach 1 with a vortech, and a peak hp of 351.3@6000 rpm
link two shows a GT with a Kenne Bell, and a peak hp of 350.8@6000rpm
we could not get closer if we tried, a net differene of 1/2 HP. at the same high rpm.
but look at the torque numbers on both, the KB is making over 350ft/lbs from 2500 to about 4700rpm. while the vrotech is doing exactly what we expect, gaining power as speed climbs. at 2500rpm it only makes 216ft,lbs.
that equates to 166hp vs 103hp at 2500rpm better by 63hp
by 4500rpm it is 300hp vs 264hp better by 36hp
by 5500rpm it is 345hp vs 337hp better by 8hp
and even at 6000rpm
i dont car what you say, you need to pass 4000rpm and 5000rpm before you get to 6000rpm.
before someone says something about diffent engines on different days on different dynos. no dyno is going to be off by over 130ft/lbs at 2500rpm
http://www.kennebell.net/media/articles/2_SCREW.pdf
here are links to 2 different magazines testing 2 different 4.6. I know it is hard to figure out, but please look close at it all.
link one shows a Mach 1 with a vortech, and a peak hp of 351.3@6000 rpm
link two shows a GT with a Kenne Bell, and a peak hp of 350.8@6000rpm
we could not get closer if we tried, a net differene of 1/2 HP. at the same high rpm.
but look at the torque numbers on both, the KB is making over 350ft/lbs from 2500 to about 4700rpm. while the vrotech is doing exactly what we expect, gaining power as speed climbs. at 2500rpm it only makes 216ft,lbs.
that equates to 166hp vs 103hp at 2500rpm better by 63hp
by 4500rpm it is 300hp vs 264hp better by 36hp
by 5500rpm it is 345hp vs 337hp better by 8hp
and even at 6000rpm
i dont car what you say, you need to pass 4000rpm and 5000rpm before you get to 6000rpm.
before someone says something about diffent engines on different days on different dynos. no dyno is going to be off by over 130ft/lbs at 2500rpm
Sorry....just wanted to let things unfold a little further. You just can't change some peoples mind no matter how much tech and fact you present. Regardless how much you throw at them, theirs is always better.prsrizdgt said:
That being said, if you go over to the TCCOA site and talk to some of the guy running the Vortech's on their cars, they'll tell you that although it's a nice jump in performance, they don't move like they thought they would. And the ones that are getting them to go half decently at all have to gear them and run high stall set ups just to be on par with the AED guys. Just too damn much weight to move I suppose. I guess that's why all of the bigger (heavier) vehicles (Cobra, Lightning, Top fuel Cars) use the positive displacement. The Centi's just don't move enough air on the bottom end to sustain their CID, or their needs.
WhiteDevil69
New Member
Nice, yah, i think that was the proof he wanted to see. I guess we have detemined that it really depends on your whole setup rather than just which blower is better..prsrizdgt said:
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