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Premium Member
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Discussion Starter #1
Guys

What would you recommend between the two for manufacturer. I have a stock 5.0 EFI with 65 mm throttle body and 70 mm MAF. I would go for the low end of the boost spectrum. Which is the cleanest installation and best overall performance and durability. What unit would you recommend.

Thanks
 

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Senior Member
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6,546 Posts
Easiest install is the kenne bell.

Overall performance is way too dependent on the engine itself.

You'll get more torque down low (driving grins) from a stock motor with a kenne bell.

You'll like make more HP up top with the Vortech.

With a hot engine the Vortech would for sure be the way to go. With a stock to mild one the Kenne Bell is a great choice.
 

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Premium Member
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Discussion Starter #4
Thanks for the info.

:cool:
 

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Allen English
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A way to look at these two different types of superchargers is:

Vortec = A centrifugal supercharger is more suitable for max top-end boost. It will kick in at a heigher RPM, thus providing less uncontrolable driving off the line (Tire spin).

Kenny Bell = Is a roots style supercharger and will give you gobbs of power at any RPM. My favorite kind of supercharger! Could pose a problem off the line in a race with a car like these.

You probibly new all of this already. As Ozona said the Kenny Bell may be a good choice for a stock motor. I like having power on demand - What do you like?

 

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Discussion Starter #7
Power on demand. I dont need the top end. I want the lower end grunt right now.....
:cool:
 

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Going nowhere fast.
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19,728 Posts
Actually the KB is a screw type, not a Roots. It is internal compression meaning that air exits the unit at a higher pressure but similar volume. The Vortech (Vortec is a type of Chevy cylinder head) is also an internal compression design, being a centrifugal compressor.

You will get as much or more boost at any RPM with the Keene Bell. You can pick the pulley that matches the maximum boost of the Vortech. I don't know the reason for the claim that the Vortech has more top end.

A Roots-type blower simply moves air, the compression is external to the blower (compresion occurs in the manifold the pistons). Such a blower is a little less efficient at making boost, and heats the air more for a given amount of boost, but uses much less power when not making boost (often less than 1 HP). This is why Eatons (a roots type) are used for almost all stock commercial applications except for Keene Bells on a few sportscars. Because they are "leaky" and respond well to throttling, Roots work well with carbs, esp. in the suck-through configuration.

Mike
 

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FFCobra Craftsman
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711 Posts
Twin screw KB without a doubt.

I installed an 8-pound kit on my 2002 f-150 in a weekend. Your install will be alot easier I'm sure.

Boost will depend on where you put your foot on the throttle. Full boost will be imidiate. You will not have to wait for full boost at a higher RPM like centrifical superchargers. Some of the others will require an extra line to the oil pan. KB system does not.

Raymond
 

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Since the KB is better on torgue...and the Vortech better up in the band.....wouldn't it be harder to launch with something producing tons of torque down low without blowing the tires off the rims v/s the Vortech??

TimBoothe
 

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Tim

I haven't found that to be a problem at my boost level (5psi). The way the torque comes on is very linear and easy to modulate. The nice thing is that I don't have to slip the clutch at all to launch the car. Leaving at idle and rolling into the gas quickly transfers the weight to the rear tires and hooks the car up really well without trying to slip the clutch and modulate the gas to stay in the power band.
 

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Junior Charter Member
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Originally posted by TimBoothe:
Since the KB is better on torgue...and the Vortech better up in the band.....wouldn't it be harder to launch with something producing tons of torque down low without blowing the tires off the rims v/s the Vortech??

TimBoothe
Not unless you forget to install the throttle body and linkage =) Just because it's capable of producing more power doesn't make it harder to control.

The KB was the best setup I ever ran. I will be dumping the turbo and going with a 2200 on the Cobra.
 

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Senior Charter Member
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wouldn't it be harder to launch
Leaving at idle
If you jumped from your Camry, hell if you jumped from your normally-apirated FFR, into my car at the track, and pulled up to the lights, you'd just sit there spinning away at the solid green.

It does take a little practice. The trick is just what Mikes says--launch from idle-- this is the hard part. Typically,the guy in the other lane lane has just smothered you with burn-out rubber smoke, his engine is revving at about 5k, hundreds of people are watching,your heart is pounding, a drip of sweat is falling into your eye, and you're trying to time the green as the yellows descend. Then the the guy in the other lane leaps out of the hole and shoots ahead of you and guess what you do--------launch from idle.

Under these circustances, the first few times, if not days, it does take a bit of self-control to simply launch from idle. LITERALLY. JUST LIKE YOU'D DO FROM ANY RED TRAFFIC LIGHT (with a cop right behind you!!!). Only after you're rolling can you put it to the floor in second.
The awsome torque at that point can take your breath away.

By the way, the best thing I like about my Kenne Bell has not been mentioned. For most of my driving, I don't even use it. When your foot isn't "into it"(98%of the time) the engine acts just as if you didn't have a blower on it. Great mileage, no issues, no sound. Totally stealth.

Needless to say, go KB.
 

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Charter Member
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If you run the Kenne Bell, try to stay away from rear ends with gearing above 3.55 ratio. These ratios act as torque multipliers, which you do not need with the KB producing lots of torque at the lower rpms.
I run 3.55 ration rear end and my KB will light up the tires without any effort. Wish I was running a 3.25 or even 3.08.

If you run a centrifuge blower, then I would tend to run rearend ratios of 3.55 or higher (3.73, 4.22, etc). This will help spool up the boost quicker.
 

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Tropically Twisted
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1,727 Posts
We're going to run the tbird's 3.08, so it should be fine. We have a 3.27 ring and pinion & a rebuild kit just in case we choose to go with a slightly lower gearing in the future. I think the 3.08 should work okay for now.
 

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What size MAF sensor, throttle body, and injectors are you guys running with the KB?

Is a 77mm MAF sensor, 70mm TB, and 36 lb/hr injectors good for around 400FWHP on a 5.0L engine?

Thanks,
Charlie
 

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FFCobra Master Craftsman
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1,170 Posts
Did you change your heads?

That would be the first thing before adding a supercharger... I guess.

Olivier
 

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Junior Charter Member
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I have a vortech, 9 psi on my 351 and it's was a lot of work to install it, a Kb would be a lot easier... but like olivier said, I would do a head swap first, In my case the vortech was not a direct bolt on....

A good set of AFR would give you close to 400 hp

Nick
 
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