Centrifugal or Positive Displacement?

[TwoValveKid]

I know most of you guys are lightning and '03 snake owners but i want your opinion. Ive got a 99 GT that im considering putting a supercharger on it and i was wondering which is better. I know the centrifugals such as a Paxton put out more power but you have to be at at least 3000 rpm or so so really start getting boost. i like the idea of the positive displacement such as the kenne bell or Allen engine development cause you get basically full boost at low rpm...gonna be mainly a street car. just curious which might be better i dont mind either one. I like the way a cetnrifugal looks under the hood but the kenne bell looks sweet too...any suggestions?

 

[PowerCobra98]

The choice in the end comes down to you. But for my two cents I like my Vortech on my Cobra. It looks awesome, performs awesome, and sounds great.

 

[stangin]

After having had both a Vortec and now the 03 Cobra I would never buy another Vortec again. That is how impressive the roots type blower is. Its like owning a big block car, absolute instant thottle response, period. This is much more impressive when giving someone a ride, normal to second gear, then shift into second and at about 1800 rpm floor it and watch the reaction of the passenger lol if they dont grab the dashboard then repeat procedure in third. I do miss the sound of the Vortec though at idle, at least you know you have a S/C, my Eaton does not make any noise at all until WOT then that is all you hear.

 

[Blown306]

Originally posted by TwoValveKid
I know the centrifugals such as a Paxton put out more power

Not true. The Blowzilla 2.2 liter compressor is rated at 953 cfm and can provide up to 18psi boost on a 302. You're going to hear a different opinion from everyone who's force inducted. It's going to come down to you deciding on what's best for your situation, factoring in price, driving style, power range, combo, installation factors, longevity and system availability. Do your research, gather the facts about each style, and pick the one you want. No matter what, you'll bolt on more power.

Personally, I would get screwed....twice.

 

[TwoValveKid]

Thanks Guys...i think im prolly eventually go with a kenne belle saleen or allen. i dont like driving around at 4k with full boost...i like the fact its all at a low rpm and has instant throttle response. Any ideas where i can get one for my 99 gt for a decent price? thanks

 

[97whitecobra]

Is it bad for longevity to, say, cruise at 80 mph or 3000 rpm on the highway for a period of time while under boost?

Also is there a root style available for the 97 Cobra? If yes how much are they? I know I guess I could have just checked the manufacturers web sites.

thanks

 

[NastyWS6]

I would say which ever one is cheaper, but I prefer the centrifugal blowers.

 

[akatherazor4]

Okay in this thread I have seen it mentioned twice about cruising at a certian rpm under boost. This is a big misconception most guys have before supercharging their vehichle (Any type of blower). Now I have owned a Kenne Bell supercharger (Installed it on my 99 Dakota R/T) and I also have a Vortech on my Cobra currently.

Under normal daily driving conditions you will almost never get you car under boost. The blower will stay in Vacume through all of this, unless you have a lead foot.;-) I can take my car to 6000rpms and hold it there under part throttle and not be under boost at all. If you have never experienced a supercharged vehichle then I highly suggest finding one to inspect and ride in.

With that said I prefer my centrifugal over the twin screw. It's just a matter of personal preference. The Vortech just keeps pulling harder as the rpm's build thus keeping you pinned to the seat. The twin screw on the other hand had that instant pull but got old to me within 2 weeks time. Now these were 2 different vehichles with different types of forced induction so the comparison may not be 100% fair. The 03's do very well with the twin screws and it's all in what you like.

Razor.:beer:

 

[Booyah]

Originally posted by 97whitecobra
Is it bad for longevity to, say, cruise at 80 mph or 3000 rpm on the highway for a period of time while under boost?

Also is there a root style available for the 97 Cobra? If yes how much are they? I know I guess I could have just checked the manufacturers web sites.

thanks

As Razor already stated, as long as you aren't at WOT you will not encounter boost.

Kenne Bell makes a supercharger kit for 96-98 Cobra's and they run between $3500 - $4000 depending on if you get satin or polished and a few other options.

 

[Blown306]

Razor is correct, except for the part about the '03 Cobra's having a twin screw (and the centrifugal part lol j/k)...I don't think Eaton put the twin screw into production yet, pretty sure it's a roots type in the 03's.

I found this on the KB website...interesting stuff:

Kenne Bell vs. Eaton - '03 Cobra Dyno Comparisons

 

[akatherazor4]

Originally posted by Blown306
Razor is correct, except for the part about the '03 Cobra's having a twin screw (and the centrifugal part lol j/k)...I don't think Eaton put the twin screw into production yet, pretty sure it's a roots type in the 03's.

I found this on the KB website...interesting stuff:

Kenne Bell vs. Eaton - '03 Cobra Dyno Comparisons

Sorry about that. I always classify a positive displacment blower as a twin screw even though it's not always the case.

Razor.:beer:

 

[TwoValveKid]

Yeah guys...i was thinkin about it...being is its gonna be mainly a street car and i like traction...all be it...with either one...im gonna have issues...im thinkin i may have less with a centrifugal because im not gettin ALL boost the second i hit the throttle...if i do that im prolly gonna go with a Paxton...or anything else thats kinda loud im not one of those people who likes a quiet charger...i want something you can at least hear air rushin in and whistling every now and again

 

[Blown306]

No problem Razor :beer:

Good luck with your project TwoValveKid...let us know how it goes and always post up any questions that come up along the way! :burnout:

 

[GR8WHITE]

The only companies making 2V "roots" or "screw" type blowers are Saleen, Lysholm (Manufacturer of the S281E blower), FRPP has one for the 96-98 headed vehicles, and Rousch, which I believe is a slight variation of the Lyscholm unit Saleen uses.
If boost is the way you've decided to go, I'd save a touch more and get the single turbo kit. There is no comparison between a turbo car and an SC'd car. With mild to moderate boost the lag is nonexistent to very minimal. The HP they make is consistent. There is very little variation in higher altitudes even, since the turbo builds it's own barometric pressure. Which means what you're car runs in E town NJ will be almost identical to what it runs in mile high Denver. I've owned and or driven all variations of Sc'd cars, nitroused cars and one single turbo 2000 GT. The torque the GT made was so impressive, it was what sealed the deal for me. My next power adder will be a turbo. Once I finish prepping the motor itself for higher boost levels.

 

[ZeroSpinn]

aluminum block probs.?

I have an '01, and hope to eventually upgrade the motor and put a Kenne Bell on it (if it ever comes out :rollseyes ). Is the stuff about aluminum blocks and positive displacement true? That crap about aluminum can't handle the low end torque and what not. Should I switch to '03 iron block?

 

[mbuono]

Love my Kenne Bell on my 347 Cobra.

 

[IUP99snake]

this might be a little biased, but if you go with a supercharger, you should go with a procharger!! The kit comes standard with a huge intercooler. But, you can't go wrong with a turbo. If I could afford it, and do it all over again, I probably would have went with a single-turbo setup. Don't get me wrong, the procharger still makes me grin from ear to ear!! the thing never, ever gets old!

Heres the bottom line... if you choose to go with a supercharger, get a procharger. if not, get a turbo. they are a lot more expensive though.

like I said... its a little biased. hehe

-Homer

-Homer

 

[Peter]

Well I am also biased. I have had my vortech
s-trim on for 2 years now and 15 thousand miles,
about 30 full passes at the 1/4 a best off 11.67,
I don't think you would go wrong with a vortech-
and get some good grip tires you will need them!

Pete
:thumbsup:

 

[brad65ford]

vortech has had a good name for some time now. I've heard more stories of people have to send back their head unites back to pro-charger because of leaks. IMO a centrifugal blower will make you more power at max rpm. The positive displacement gives you more down stairs power quicker than the other. The 03 shows the results of f'n with people on the street how quick it takes off.

 

[GR8WHITE]

Re: aluminum block probs.?

Originally posted by ZeroSpinn
I have an '01, and hope to eventually upgrade the motor and put a Kenne Bell on it (if it ever comes out :rollseyes ). Is the stuff about aluminum blocks and positive displacement true? That crap about aluminum can't handle the low end torque and what not. Should I switch to '03 iron block?

Kenne Bell has a SC for the 2003 Cobras. This SC will fit your heads.

As far as the aluminum block?!?!?! John Milovetz is running way down in the 7's on an aluminum block. Ford just told that lie to switch to the cheaper cast iron block. The 6 bolt main aluminum block is stronger and lighter. Unfortunately, it just costs more. The 2003 iron block is the same as the GT block. The block is only machined to accept the DOHC front timing cover.