Okay gearheads, need some advice. (again) lol

"Michael Johnson, PE" > wrote in message
...
> Nicholas Anthony wrote:
>> "JohnV@nn" > wrote in message
>> ups.com...
>>> BradandBrooks wrote:
>>>> I have a 93 GT with pretty low mileage (about 40,000 miles).
>>>>
>>>> It's totally stock with a 5-spd and 2.73s. Oh, I do have an X-pipe,
>>>> exhaust, subs, and timing bump. All the usual little things.
>>>>
>>>> Today, it got pretty warm here (and being way up in the foothills of
>>>> the Rockies where the air is thin), the car was a real dog. Well, not a
>>>> dog, but just not what you expect when you see the 5.0 on the side of a
>>>> Mustang.
>>>>
>>>> So, I was driving by an SVT dealer and stopped in. That was my first
>>>> mistake. (Grin.)
>>>>
>>>> I've decided to do one of two things. I only have money for one or the
>>>> other, and I'd like your thoughts.
>>>>
>>>> First scenerio is get a 9lb supercharger from Ford. That's what I want,
>>>> the Ford model, and there are no emissions testing where I live. What
>>>> kind of hp and tq increases would a 9lb give me? And, more importantly,
>>>> would I have to change the fuel pump and head gaskets, unlike the 6lb.
>>>> This will just add to the cost, but I'm not sure how much.
>>>>
>>>> When I asked an SVT tech how many hours to do this he said, "I haven't
>>>> done a 5.0 in years... why would you want to do that." Okay, so minus
>>>> the prick (which also scares the crap out of me) how many hours on the
>>>> 6 and 9 do you think it would take? Also, thought about this after, if
>>>> I had a speed shop install it, would that void warranty? Anyone know?
>>>>
>>>> The other option is to go with some 3.73s out back and some Ford Racing
>>>> "c" springs and long tubes (again, no emissions). Maybe there would be
>>>> some money left over for some pulleys.
>>>>
>>>> Both routes would be good, one car would be more powerful, but the
>>>> other would be more complete. But I can't do both. I do love to corner
>>>> the car hard (got some really sticky and wide Yokohamas on her) and
>>>> that's a blast. But I'm wondering if I shouldn't just do the SC while
>>>> I have the cash, and add other things later. But option #2 is pretty
>>>> enticing too.
>>>>
>>>> Help me out guys. Summer is running out.
>>>>
>>>> Thanks!
>>>>
>>>> Brad
>>> What point in the power band do you want the power? Would you want to
>>> feel full boost at, say, 2000 rpm or would you want the boost to roll
>>> on gradually and peak out at about 5000 - 5500? If you answered 2000
>>> rpm then you want a twin screw-type blower like the Kenne Bell.
>>> Granted it is quite a bit more money but you know what they say.
>>>
>>> BTW the centrifugal blower that Ford sells is a rebadged Powerdyne
>>> part; I just did a quick search and found the Powerdyne 9psi unit for
>>> $1599 and the FRPP-badged version at $2074 (same retailer).
>>>
>>> John
>>
>> Yes they are Powerdynes. I purchased the 6lb kit as a small boost for my
>> car so I don't harm my engine and no oil line taps and its quieter then
>> most. You can find them around the $1500 price check Ebay. They also come
>> with a FMU which saves you a few hundred bucks. If you go for a larger
>> pulley you need a by pass valve and a larger in tank fuel pump. Ask them
>> which head unit you are getting with the kit. The BD11-a is the newer
>> model so make sure that is what you are getting. The next step up is a
>> the XB-1A which can handle upto 18psi and are fine at low levels but cost
>> allot more. IMO I say go for the Ford Powerdyne if money is an issue. Its
>> a great entry way into the world of s/c the belts are rated for 50k miles
>> and you can have it rebuilt down the road for just over $300-500 with
>> kevlar belts and other improvements.
>>
>> As far as centrifugal vs roots blowers also keep in mind the centrifugal
>> (ex: Powerdyne, Procharger) will be cooler and allow a denser air flow
>> then the roots (ex: Whipple, Kenne Bell). Henceforth you can have the two
>> types of blowers producing 6psi but the centrifugal will give more power
>> cause of the denser air flow. Just some more food for thought.
>
> For the 5.0L engines there are no current Roots kits offered. He would
> have to go with a Kenne Bell kit. The twin screws are more efficient than
> the centrifugals and make less heat from compression. They also take much
> less hp to drive them at the same boost levels. The down side of the twin
> screw is there are no intercooler options for the 5.0L engines. I get
> around this by using water injection that is just as effective as an
> intercooler and in many respects is better.

The Roots type forces less dense air into the car were as a centrifugal is a
colder denser charge. Also the higher rpm hp is less with the screw type. I
can see arguments going back and forth on this for sometime on which is
better. IMO if someone is interested do allot more research while you ask
around.

Here is a nice link I found with information.
http://www.superchargersonline.com/content.asp?ID=5

Here is the keypoints of each type:

Centrifugal Type Supercharging

Recommended Usage:
Street Use - Commercial Use - Road Racing - Drag Racing


Positive Points:
1) Lots of Flexibility for Power Adjustments
2) Lower Discharge Temperatures
3) Great Reliability
4) Easy to install

Negative Points:
1) Not as much power at low RPMs as Roots or Screw type superchargers

Manufacturer Availability:
Paxton - Powerdyne - ProCharger - Vortech

Roots Type Supercharging

Recommended Usage:
Street Use - Towing - Extreme Drag Racing - Show Vehicles


Positive Points:
1) Boost throughout the entire RPM range, right off of idle
2) Highest Potential for Gain (A must-have for all-out drag racing)
3) Excellent Reliability
4) Great Appearance & Stature (Most common supercharger type for show
vehicles)

Negative Points:
1) Sometimes Violent Throttle Response
2) Lower boost ratings at higher RPMs
3) Higher Than Normal Discharge Temperatures
4) Lengthy installation times

Manufacturer Availability:
Allen Engine Development - BDS - Magna Charger - B&M- Holley -
Littlefield - Mooneyham - Weiand



Screw Type Supercharging

Recommended Usage:
Street Use - Towing - Road Racing - Drag Racing


Positive Points:
1) Great Power at Low RPMs (Great for Towing)
3) Factory Fit & Appearance
4) Great Reliability

Negative Points:
1) The Power Doesn't Keep Climbing in the High RPMs (Power curve is very
flat)
2) Challenging To Achieve High Boost Levels or CFMs
3) Lengthy installation times

Manufacturer Availability:
Kenne Belle - Whipple

"Nicholas Anthony" > wrote in
:

<lots of good & bad stuff snipped>
> Here is a nice link I found with information.
> http://www.superchargersonline.com/content.asp?ID=5
>
> Here is the keypoints of each type:
>
> Centrifugal Type Supercharging
>
> Recommended Usage:
> Street Use - Commercial Use - Road Racing - Drag Racing
>
> Positive Points:
> 1) Lots of Flexibility for Power Adjustments
> 2) Lower Discharge Temperatures
> 3) Great Reliability
> 4) Easy to install
>
> Negative Points:
> 1) Not as much power at low RPMs as Roots or Screw type superchargers

So then why do they recommend it for street use? Are they only thinking
high-winding ricemobiles?

> Manufacturer Availability:
> Paxton - Powerdyne - ProCharger - Vortech
>
> Roots Type Supercharging
>
> Recommended Usage:
> Street Use - Towing - Extreme Drag Racing - Show Vehicles
>
> Positive Points:
> 1) Boost throughout the entire RPM range, right off of idle
> 2) Highest Potential for Gain (A must-have for all-out drag
> racing) 3) Excellent Reliability
> 4) Great Appearance & Stature (Most common supercharger type for
> show
> vehicles)

If it's a show vehicle, what's a blower doing on it anyway? It ain't even
gonna be used...

> Negative Points:
> 1) Sometimes Violent Throttle Response

So instantaneous power is a bad thing? Or are they saying that you can
lose control because of the massive amount of power right off of idle? If
you can't control your car with that much power you shouldn't have a
blower.

> 2) Lower boost ratings at higher RPMs
> 3) Higher Than Normal Discharge Temperatures
> 4) Lengthy installation times
>
> Manufacturer Availability:
> Allen Engine Development - BDS - Magna Charger - B&M- Holley -
> Littlefield - Mooneyham - Weiand
>
>
> Screw Type Supercharging
>
> Recommended Usage:
> Street Use - Towing - Road Racing - Drag Racing
>
> Positive Points:
> 1) Great Power at Low RPMs (Great for Towing)
> 3) Factory Fit & Appearance
> 4) Great Reliability
>
> Negative Points:
> 1) The Power Doesn't Keep Climbing in the High RPMs (Power curve is
> very flat)

I'd love to know why a flat power curve is a bad thing.

> 2) Challenging To Achieve High Boost Levels or CFMs
> 3) Lengthy installation times
>
> Manufacturer Availability:
> Kenne Belle - Whipple

To simplify, if you'll be winding out your engine and you prefer your
powerband up in the higher end, a turbo or centrifugal is appropriate. If
you want additional power in the lower-RPM range, the roots or screw is
appropriate.

Joe
Calypso Green '93 5.0 LX AOD hatch with a few goodies
Black '03 Dakota 5.9 R/T CC

Joe wrote:
> "Nicholas Anthony" > wrote in
> :
>
> <lots of good & bad stuff snipped>
> > Here is a nice link I found with information.
> > http://www.superchargersonline.com/content.asp?ID=5
> >
> > Here is the keypoints of each type:
> >
> > Centrifugal Type Supercharging
> >
> > Recommended Usage:
> > Street Use - Commercial Use - Road Racing - Drag Racing
> >
> > Positive Points:
> > 1) Lots of Flexibility for Power Adjustments
> > 2) Lower Discharge Temperatures
> > 3) Great Reliability
> > 4) Easy to install
> >
> > Negative Points:
> > 1) Not as much power at low RPMs as Roots or Screw type superchargers
>
> So then why do they recommend it for street use? Are they only thinking
> high-winding ricemobiles?

My Vortech's boost starts at just over 3,000 RPM and climbs until I
shift at around 5,900 at which point it's at about 9PSI... I will
agree that it is missing the low-end grunt, especially after getting
used to the torque I was getting out of the N20... but for around town
and the occasional trip to the track I really like the centr. s/c.
Actually I didn't think i was going to like it... but I'm actually very
satisfied with it...
>
> > Manufacturer Availability:
> > Paxton - Powerdyne - ProCharger - Vortech
> >
> > Roots Type Supercharging
> >
> > Recommended Usage:
> > Street Use - Towing - Extreme Drag Racing - Show Vehicles
> >
> > Positive Points:
> > 1) Boost throughout the entire RPM range, right off of idle
> > 2) Highest Potential for Gain (A must-have for all-out drag
> > racing) 3) Excellent Reliability
> > 4) Great Appearance & Stature (Most common supercharger type for
> > show
> > vehicles)
>
> If it's a show vehicle, what's a blower doing on it anyway? It ain't even
> gonna be used...
>

Actually my car is a multi-purpose car! It's DD... It's race car...
It's a show car... LOL!

I agree though.. a Roots type sitting on top of the motor is sexier
than a centrify all plumbed up on the front of the motor... However..
I did get a win at the local car show yesterday... knocked off some
nice F-Bodys, couple of Vettes and some entries from the local
low-rider club... Let's hear it for the Mustang!! LOL!


> > Negative Points:
> > 1) Sometimes Violent Throttle Response
>
> So instantaneous power is a bad thing? Or are they saying that you can
> lose control because of the massive amount of power right off of idle? If
> you can't control your car with that much power you shouldn't have a
> blower.
>

I wouldn't say it's a bad thing.. but the way it was explained to me is
it can make your car drive like an On / Off switch... which in itself
may not be a bad thing but might get a bit tiresome if you r car is a
DD and you roast the tires at every stop light..... With the Vortech
the power comes on a bit smoother, definitely not a light switch...
LOL!!

> > 2) Lower boost ratings at higher RPMs
> > 3) Higher Than Normal Discharge Temperatures
> > 4) Lengthy installation times
> >
> > Manufacturer Availability:
> > Allen Engine Development - BDS - Magna Charger - B&M- Holley -
> > Littlefield - Mooneyham - Weiand
> >
> >
> > Screw Type Supercharging
> >
> > Recommended Usage:
> > Street Use - Towing - Road Racing - Drag Racing
> >
> > Positive Points:
> > 1) Great Power at Low RPMs (Great for Towing)
> > 3) Factory Fit & Appearance
> > 4) Great Reliability
> >
> > Negative Points:
> > 1) The Power Doesn't Keep Climbing in the High RPMs (Power curve is
> > very flat)
>
> I'd love to know why a flat power curve is a bad thing.
>
> > 2) Challenging To Achieve High Boost Levels or CFMs
> > 3) Lengthy installation times
> >
> > Manufacturer Availability:
> > Kenne Belle - Whipple
>
> To simplify, if you'll be winding out your engine and you prefer your
> powerband up in the higher end, a turbo or centrifugal is appropriate. If
> you want additional power in the lower-RPM range, the roots or screw is
> appropriate.
>
> Joe
> Calypso Green '93 5.0 LX AOD hatch with a few goodies
> Black '03 Dakota 5.9 R/T CC

Joe wrote:

>>Negative Points:
>>1) The Power Doesn't Keep Climbing in the High RPMs (Power curve is
>>very flat)
>
>
> I'd love to know why a flat power curve is a bad thing.

If RPMs are going up and power is flat, then torque must be going down.
That's why I can't keep that grin off my face around 4000RPMs (still
within the speed limits) buy crackers.

--
Tropic Green Y2K Mustang GT
W/bits & pieces
http://tinyurl.com/eh99n

Nicholas Anthony wrote:
> "Michael Johnson, PE" > wrote in message
> ...
>> Nicholas Anthony wrote:
>>> "JohnV@nn" > wrote in message
>>> ups.com...
>>>> BradandBrooks wrote:
>>>>> I have a 93 GT with pretty low mileage (about 40,000 miles).
>>>>>
>>>>> It's totally stock with a 5-spd and 2.73s. Oh, I do have an X-pipe,
>>>>> exhaust, subs, and timing bump. All the usual little things.
>>>>>
>>>>> Today, it got pretty warm here (and being way up in the foothills of
>>>>> the Rockies where the air is thin), the car was a real dog. Well, not a
>>>>> dog, but just not what you expect when you see the 5.0 on the side of a
>>>>> Mustang.
>>>>>
>>>>> So, I was driving by an SVT dealer and stopped in. That was my first
>>>>> mistake. (Grin.)
>>>>>
>>>>> I've decided to do one of two things. I only have money for one or the
>>>>> other, and I'd like your thoughts.
>>>>>
>>>>> First scenerio is get a 9lb supercharger from Ford. That's what I want,
>>>>> the Ford model, and there are no emissions testing where I live. What
>>>>> kind of hp and tq increases would a 9lb give me? And, more importantly,
>>>>> would I have to change the fuel pump and head gaskets, unlike the 6lb.
>>>>> This will just add to the cost, but I'm not sure how much.
>>>>>
>>>>> When I asked an SVT tech how many hours to do this he said, "I haven't
>>>>> done a 5.0 in years... why would you want to do that." Okay, so minus
>>>>> the prick (which also scares the crap out of me) how many hours on the
>>>>> 6 and 9 do you think it would take? Also, thought about this after, if
>>>>> I had a speed shop install it, would that void warranty? Anyone know?
>>>>>
>>>>> The other option is to go with some 3.73s out back and some Ford Racing
>>>>> "c" springs and long tubes (again, no emissions). Maybe there would be
>>>>> some money left over for some pulleys.
>>>>>
>>>>> Both routes would be good, one car would be more powerful, but the
>>>>> other would be more complete. But I can't do both. I do love to corner
>>>>> the car hard (got some really sticky and wide Yokohamas on her) and
>>>>> that's a blast. But I'm wondering if I shouldn't just do the SC while
>>>>> I have the cash, and add other things later. But option #2 is pretty
>>>>> enticing too.
>>>>>
>>>>> Help me out guys. Summer is running out.
>>>>>
>>>>> Thanks!
>>>>>
>>>>> Brad
>>>> What point in the power band do you want the power? Would you want to
>>>> feel full boost at, say, 2000 rpm or would you want the boost to roll
>>>> on gradually and peak out at about 5000 - 5500? If you answered 2000
>>>> rpm then you want a twin screw-type blower like the Kenne Bell.
>>>> Granted it is quite a bit more money but you know what they say.
>>>>
>>>> BTW the centrifugal blower that Ford sells is a rebadged Powerdyne
>>>> part; I just did a quick search and found the Powerdyne 9psi unit for
>>>> $1599 and the FRPP-badged version at $2074 (same retailer).
>>>>
>>>> John
>>> Yes they are Powerdynes. I purchased the 6lb kit as a small boost for my
>>> car so I don't harm my engine and no oil line taps and its quieter then
>>> most. You can find them around the $1500 price check Ebay. They also come
>>> with a FMU which saves you a few hundred bucks. If you go for a larger
>>> pulley you need a by pass valve and a larger in tank fuel pump. Ask them
>>> which head unit you are getting with the kit. The BD11-a is the newer
>>> model so make sure that is what you are getting. The next step up is a
>>> the XB-1A which can handle upto 18psi and are fine at low levels but cost
>>> allot more. IMO I say go for the Ford Powerdyne if money is an issue. Its
>>> a great entry way into the world of s/c the belts are rated for 50k miles
>>> and you can have it rebuilt down the road for just over $300-500 with
>>> kevlar belts and other improvements.
>>>
>>> As far as centrifugal vs roots blowers also keep in mind the centrifugal
>>> (ex: Powerdyne, Procharger) will be cooler and allow a denser air flow
>>> then the roots (ex: Whipple, Kenne Bell). Henceforth you can have the two
>>> types of blowers producing 6psi but the centrifugal will give more power
>>> cause of the denser air flow. Just some more food for thought.
>> For the 5.0L engines there are no current Roots kits offered. He would
>> have to go with a Kenne Bell kit. The twin screws are more efficient than
>> the centrifugals and make less heat from compression. They also take much
>> less hp to drive them at the same boost levels. The down side of the twin
>> screw is there are no intercooler options for the 5.0L engines. I get
>> around this by using water injection that is just as effective as an
>> intercooler and in many respects is better.
>
> The Roots type forces less dense air into the car were as a centrifugal is a
> colder denser charge. Also the higher rpm hp is less with the screw type. I
> can see arguments going back and forth on this for sometime on which is
> better. IMO if someone is interested do allot more research while you ask
> around.
>
> Here is a nice link I found with information.
> http://www.superchargersonline.com/content.asp?ID=5

Personally, I wouldn't put too much credibility to this site, or for
that many any site, that sells superchargers for a profit. There are
many incorrect statements in the text you quoted.

> Here is the keypoints of each type:
>
> Centrifugal Type Supercharging
>
> Recommended Usage:
> Street Use - Commercial Use - Road Racing - Drag Racing

Most commercial uses need low/mid range torque for towing or hauling
heavy loads etc. It is rather inconvenient, unreliable and uneconomical
to spin an engine to 5,000+ rpm to pull a load. Nearly all trucks,
recreation vehicles etc. that need a blower use a Roots or twin screw
type. Plus, most heavy commercial trucks use turbochargers.

> Positive Points:
> 1) Lots of Flexibility for Power Adjustments

What does this mean?

> 2) Lower Discharge Temperatures

Lower than a Roots blower but not a twin screw.

> 3) Great Reliability

Roots and twin screws are rated to last 200k-300k miles. A centrifugal
is not rated that long. OEMs use Roots blowers because they are cheap
and extremely reliable.

> 4) Easy to install

Most non-intercooled systems are easier to install compared to a
Roots/twin screw. Throw in an intercooler and they are just as complicated.

> Negative Points:
> 1) Not as much power at low RPMs as Roots or Screw type superchargers
>
> Manufacturer Availability:
> Paxton - Powerdyne - ProCharger - Vortech
>
> Roots Type Supercharging
>
> Recommended Usage:
> Street Use - Towing - Extreme Drag Racing - Show Vehicles
>
>
> Positive Points:
> 1) Boost throughout the entire RPM range, right off of idle
> 2) Highest Potential for Gain (A must-have for all-out drag racing)
> 3) Excellent Reliability
> 4) Great Appearance & Stature (Most common supercharger type for show
> vehicles)
>
> Negative Points:
> 1) Sometimes Violent Throttle Response

It's called torque, not "violent throttle response". This is a
laughable statement. A negative? Not hardly. Plus the power is easily
modulated with the throttle. They make it sound like the throttle is an
on/off switch.

> 2) Lower boost ratings at higher RPMs

With a roots blower this is true to a certain extent. However, it
usually occurs because the size of blower used is too small for the
boost level desired on a particular engine displacement.

> 3) Higher Than Normal Discharge Temperatures

This is very true.

> 4) Lengthy installation times

Not necessarily true. Most kits are just a little more complicated than
installing a centrifugal blower.

> Manufacturer Availability:
> Allen Engine Development - BDS - Magna Charger - B&M- Holley -
> Littlefield - Mooneyham - Weiand
>
>
>
> Screw Type Supercharging
>
> Recommended Usage:
> Street Use - Towing - Road Racing - Drag Racing
>
>
> Positive Points:
> 1) Great Power at Low RPMs (Great for Towing)

Or launching with slicks bolted to the rear. Or just sending tires up
in a cloud of smoke. Or effortlessly passing a car without down
shifting. You get my point.

> 3) Factory Fit & Appearance
> 4) Great Reliability

True. Twin screws will typically out live the engine.

In addition, twin screws take the least amount of hp to spin per psi of
boost, they have the lowest discharge temperatures, are quiet, provide
full rated boost from idle to redline. Also, the statement that twin
screw don't provide high rpm horsepower is BS. They are great for it.
With all the low end torque they produce the engine can be setup to be a
high rpm monster with no low/mid range torque/drivability penalty. Do
this with a centrifugal blower and it would be a disaster for
drivability. Take a look at the dyno charts at the link below and tell
me if power drops off at higher rpms.

http://www.kennebell.net/supercharge...gt05-06_3v.htm

> Negative Points:
> 1) The Power Doesn't Keep Climbing in the High RPMs (Power curve is very
> flat)

This is just a flat out false statement. It is the torque curve that is
flat, not the hp curve. A flat torque curve is a good thing. Look at
the curves in the above link.

> 2) Challenging To Achieve High Boost Levels or CFMs

WTF are they talking about? Put the right size blower on an engine and
it will move all the air you need at any psi level you want. This is an
idiotic statement and quite scary from someone claiming to be a blower
expert.

> 3) Lengthy installation times

Not really. The Kenne Bell kits can be done in a about a day or two
depending on the installer's experience level. Add an intercooler to a
centrifugal (most Kenne Bell kits are intercooled now) and the
installation time is nearly identical.

> Manufacturer Availability:
> Kenne Belle - Whipple

The Kenne Bell kits for the Mustangs provide the biggest hp increases
per psi of boost of any supercharger type. Their 8.5 psi intercooled
kit makes 456 rear wheel hp on an otherwise stock '05+ GT. This is the
same as 536 hp at the crank and is 90 rwhp more than a stock 03-04
Cobra. ProCharger, Vortech, Paxton etc. can't match them psi to psi on
identical engines. Also, the area under the torque/hp curves for twin
screws is greater which makes them faster at the track than centrifugals
when peak hp levels are equal. Typically, a twin screw will run the
same ETs as a centrifugal with 30-40 less rwhp with weight etc. being
equal between the cars.

Just to clarify, the difference between Roots and twin screw blowers is
a Roots is an air pump and the twin screw is a compressor. The Roots
moves air to the intake manifold which is where it gets compressed.
Also, there is a slight reversal in the direction of air flow because of
this since the manifold air is at a higher pressure than the air in the
blower. This flow reversal heats up the air more and makes the Roots
less efficient. The twin screw compresses the air in the blower not the
intake manifold so the air flows one way all the time. This lets the
discharge temps be much cooler than a Roots and even cooler than a
centrifugal, psi for psi of boost. It also makes twin screws more
efficient.

John S. wrote:
> Joe wrote:
>> "Nicholas Anthony" > wrote in
>> :
>>
>> <lots of good & bad stuff snipped>
>>> Here is a nice link I found with information.
>>> http://www.superchargersonline.com/content.asp?ID=5
>>>
>>> Here is the keypoints of each type:
>>>
>>> Centrifugal Type Supercharging
>>>
>>> Recommended Usage:
>>> Street Use - Commercial Use - Road Racing - Drag Racing
>>>
>>> Positive Points:
>>> 1) Lots of Flexibility for Power Adjustments
>>> 2) Lower Discharge Temperatures
>>> 3) Great Reliability
>>> 4) Easy to install
>>>
>>> Negative Points:
>>> 1) Not as much power at low RPMs as Roots or Screw type superchargers
>> So then why do they recommend it for street use? Are they only thinking
>> high-winding ricemobiles?
>
> My Vortech's boost starts at just over 3,000 RPM and climbs until I
> shift at around 5,900 at which point it's at about 9PSI... I will
> agree that it is missing the low-end grunt, especially after getting
> used to the torque I was getting out of the N20... but for around town
> and the occasional trip to the track I really like the centr. s/c.
> Actually I didn't think i was going to like it... but I'm actually very
> satisfied with it...

Your last sentence is what it is all about. If you're happy who cares
what I think.

>>> Manufacturer Availability:
>>> Paxton - Powerdyne - ProCharger - Vortech
>>>
>>> Roots Type Supercharging
>>>
>>> Recommended Usage:
>>> Street Use - Towing - Extreme Drag Racing - Show Vehicles
>>>
>>> Positive Points:
>>> 1) Boost throughout the entire RPM range, right off of idle
>>> 2) Highest Potential for Gain (A must-have for all-out drag
>>> racing) 3) Excellent Reliability
>>> 4) Great Appearance & Stature (Most common supercharger type for
>>> show
>>> vehicles)
>> If it's a show vehicle, what's a blower doing on it anyway? It ain't even
>> gonna be used...
>>
>
> Actually my car is a multi-purpose car! It's DD... It's race car...
> It's a show car... LOL!
>
> I agree though.. a Roots type sitting on top of the motor is sexier
> than a centrify all plumbed up on the front of the motor... However..
> I did get a win at the local car show yesterday... knocked off some
> nice F-Bodys, couple of Vettes and some entries from the local
> low-rider club... Let's hear it for the Mustang!! LOL!

Us twin screw guys see the centrifugals as a hair dryer on steroids.

>>> Negative Points:
>>> 1) Sometimes Violent Throttle Response
>> So instantaneous power is a bad thing? Or are they saying that you can
>> lose control because of the massive amount of power right off of idle? If
>> you can't control your car with that much power you shouldn't have a
>> blower.
>>
>
> I wouldn't say it's a bad thing.. but the way it was explained to me is
> it can make your car drive like an On / Off switch... which in itself
> may not be a bad thing but might get a bit tiresome if you r car is a
> DD and you roast the tires at every stop light..... With the Vortech
> the power comes on a bit smoother, definitely not a light switch...
> LOL!!

In some ways I thing the twin screw/Roots blowers are easier to control
power delivery than a centrifugal. The power for a centrifugal comes on
like a freight train in the upper rpm band. With the twin screw on my
car I can modulate the power with great finesse with throttle position.
It's an apples and oranges thing.

>>> 2) Lower boost ratings at higher RPMs
>>> 3) Higher Than Normal Discharge Temperatures
>>> 4) Lengthy installation times
>>>
>>> Manufacturer Availability:
>>> Allen Engine Development - BDS - Magna Charger - B&M- Holley -
>>> Littlefield - Mooneyham - Weiand
>>>
>>>
>>> Screw Type Supercharging
>>>
>>> Recommended Usage:
>>> Street Use - Towing - Road Racing - Drag Racing
>>>
>>> Positive Points:
>>> 1) Great Power at Low RPMs (Great for Towing)
>>> 3) Factory Fit & Appearance
>>> 4) Great Reliability
>>>
>>> Negative Points:
>>> 1) The Power Doesn't Keep Climbing in the High RPMs (Power curve is
>>> very flat)
>> I'd love to know why a flat power curve is a bad thing.
>>
>>> 2) Challenging To Achieve High Boost Levels or CFMs
>>> 3) Lengthy installation times
>>>
>>> Manufacturer Availability:
>>> Kenne Belle - Whipple
>> To simplify, if you'll be winding out your engine and you prefer your
>> powerband up in the higher end, a turbo or centrifugal is appropriate. If
>> you want additional power in the lower-RPM range, the roots or screw is
>> appropriate.
>>
>> Joe
>> Calypso Green '93 5.0 LX AOD hatch with a few goodies
>> Black '03 Dakota 5.9 R/T CC
>

GILL wrote:
> Joe wrote:
>
>>> Negative Points:
>>> 1) The Power Doesn't Keep Climbing in the High RPMs (Power curve is
>>> very flat)
>>
>>
>> I'd love to know why a flat power curve is a bad thing.
>
> If RPMs are going up and power is flat, then torque must be going down.
> That's why I can't keep that grin off my face around 4000RPMs (still
> within the speed limits) buy crackers.

I can't get the grin off my face from 2,000 rpm to redline. With a
twin screw, it is not the power curve that is flat. It is the torque
curve. When the torque curve is flat the hp curve is not and keeps
increasing with rpm level. Check out the curves he
http://tinyurl.com/s69nm Show me a dyno run from a centrifugal that
matches the KB kit at 8.5 psi of boost on an otherwise bone stock 05+
Mustang GT.

Michael Johnson, PE wrote:
> GILL wrote:
>
>> Joe wrote:
>>
>>>> Negative Points:
>>>> 1) The Power Doesn't Keep Climbing in the High RPMs (Power curve is
>>>> very flat)
>>>
>>>
>>>
>>> I'd love to know why a flat power curve is a bad thing.
>>
>>
>> If RPMs are going up and power is flat, then torque must be going
>> down. That's why I can't keep that grin off my face around 4000RPMs
>> (still within the speed limits) buy crackers.
>
>
> I can't get the grin off my face from 2,000 rpm to redline. With a
> twin screw, it is not the power curve that is flat. It is the torque
> curve. When the torque curve is flat the hp curve is not and keeps
> increasing with rpm level. Check out the curves he
> http://tinyurl.com/s69nm Show me a dyno run from a centrifugal that
> matches the KB kit at 8.5 psi of boost on an otherwise bone stock 05+
> Mustang GT.

http://tinyurl.com/euykk
They both drop in torque high in the RPMs
Up high they compare fairly close, KB rules down low and ATI is peaky,
and to catch up it has that mid-high RPM "rush" so they are both fun,
when "running", right?

--
Tropic Green Y2K Mustang GT
W/bits & pieces
http://tinyurl.com/eh99n

GILL wrote:
> Michael Johnson, PE wrote:
>> GILL wrote:
>>
>>> Joe wrote:
>>>
>>>>> Negative Points:
>>>>> 1) The Power Doesn't Keep Climbing in the High RPMs (Power curve is
>>>>> very flat)
>>>>
>>>>
>>>>
>>>> I'd love to know why a flat power curve is a bad thing.
>>>
>>>
>>> If RPMs are going up and power is flat, then torque must be going
>>> down. That's why I can't keep that grin off my face around 4000RPMs
>>> (still within the speed limits) buy crackers.
>>
>>
>> I can't get the grin off my face from 2,000 rpm to redline. With a
>> twin screw, it is not the power curve that is flat. It is the torque
>> curve. When the torque curve is flat the hp curve is not and keeps
>> increasing with rpm level. Check out the curves he
>> http://tinyurl.com/s69nm Show me a dyno run from a centrifugal that
>> matches the KB kit at 8.5 psi of boost on an otherwise bone stock 05+
>> Mustang GT.
>
> http://tinyurl.com/euykk
> They both drop in torque high in the RPMs
> Up high they compare fairly close, KB rules down low and ATI is peaky,
> and to catch up it has that mid-high RPM "rush" so they are both fun,
> when "running", right?

The ATI is still 14 peak hp off the KB even with 0.5 psi more peak
boost. The ATI torque curve is pretty good for a centrifugal. Either
blower will put a smile on your face. The biggest drawback I see to a
centrifugal is the narrow power band for peak boost. Beyond first and
second gear it is hard to be in the meat of its boost curve on the
street. For some people though this isn't a negative and is even seen
as a positive. Still though, it is all good.

"Joe" > wrote
>> Screw Type Supercharging
>> Manufacturer Availability:
>> Kenne Belle - Whipple

Lysholm? The one being used on the Ford GT?
--
Scott W.
'68 Ranchero 500 302
'69 Mustang Sportsroof 351W
ThunderSnake #57
http://home.comcast.net/~vanguard92/