It's been a study in intake and exhaust design for decades. Race cars even 50 years ago were exceeding 100% VE naturally aspirated. It actually depends more on the exhaust system than the intake side. The outgoing exhaust gas can pull air into the combustion chamber at such a rate that the intake port, in the immediate vicinity of the valve seat, would see higher-than-atmospheric pressure.



As for the whole centri. vs. positive displacement supercharger arguement there really isn't much to say other than it's just a matter of personal preference. There is a lot of misinformation flying around. At the very lowest part of the power band there is no advantage either way...neither system is making boost at 1000 rpms. I run a centri because I liked the total package and I got a great deal. I don't miss any lowend power, boost hits the instant I floor the pedal, and it's been very reliable.

 

I second that motion minus the respectfully

How can you join a thread singing the praises of the Whipple & Kenne Bell SC for an 04-06 F150(that is what we are talking about) when the KB is not available and there are no plans for it to become available? Call KB and ask them..

 

While doing research on the different blowers out there I came across this article about the Procharger P-1SC. I found it to be interesting what the claims of the manufacturer are compared to the test results. I am in no way saying that the procharger is not a good unit, but I thought I would throw this out this and see what everyone's thoughts are on this.

http://www.vortechsuperchargers.com/...s%20vortech%22

Oh yeah, did I say that vortech is the company that had the study done on the procharger. I was pretty set on getting the procharger, but as of right now I am looking at other options.

 

The link explains it all . IF I were to buy a centri type blower I would go with Paxton or Vortech.

 

My most recent reading / surfing tells me this:
The intake port needs a venturi to speed the intake charge into the cylinder. It looks like about a 15 % differential is the norm. The exhaust port needs to be at least slightly smaller than the exhaust header inlet to keep the exhaust from backing up - I am not sure how important this becomes with added boost.

I am running a Paxton on my truck, which is the lightest config of the 97+ trucks. It works great, but if I were to put an s/c on one of the four door barges, it would be a pos dis for the low end grunt.
Let the debate continue!

 

Another vote for the positive displacement blowers!!

 

OK so here is FACTual data. This graph is between my 2 2006 GT Mustangs with less than 1000 miles on them. (Well OK, the centi car is my wifes) Both are identicle 2006 4.6L 3V engines, same rear gears, both 5 speeds, exact same option packages. Pulls done back to back on the same day, (within 1/2 hr) on the same dyno, in 4th gear on a Mustang chassis dyno loaded to 3800lbs and conservatively calibrated so don't start on the low HP numbers VS. the boost levels. Both of these cars are well over 400 at the tire.
Both kits are intercooled. The roots is air/water/air and the Cetrifugal is air/air with the intake temperatures almost identicle to each other on the pulls. This is as close as your going to get to a real apples to apples comparison. We built up these 2 cars to make exactly this point. I'm not saying that one is better than the other, just stating the facts and hopefully helping answer the question of which SC to choose.
Please note the following:
Blue lines are torque - Top line being the roots
Red lines are horse power - Top line being the roots
Green lines are the boost curves - again the top line is the roots
Both the Centri and the roots are at approximately 8.5lbs of boost, and yes we could spin the centi faster and make more power if we wanted to, but the intention here is to show the differences in torque and boost curves with approximately the same HP and more importantly, same boost pressure

This isn't intended to start another debate

[IMG][/IMG]

 

^Which blowers were used in this test? What was the timing set at on the engines? Did you try to maimize power on both (custom tuning) or are these canned tunes? Any extra information would be great, and thnaks for the graph comparing the two.

Ps. Which one is faster at the track?

 

Meh.
Data has already been debunked and testing is not apples-to-apples.

Since you list Vortech's info, here's ATI's info:
http://www.procharger.com/competitorhp/summary.shtml
http://www.procharger.com/consumer_alert.shtml

Like I said, simply dismissing one technology over another based on heersay and not actual data is doing yourself a dis-service.

 

If they are the same cars listed in his signature, one is a Procharger, the other is a Magnacharger (Eaton 112 I'm assuming since that is what Magnuson uses on all of thier GM stuff).

I think you are missing the point of the post. It shows the difference in the power curves between the two types of blowers really well. Even thoguh both cars make the same HP, you can clearly see that the Roots car is making a ton more torque down low then the Centri car (over 120ft-lbs at 3200). The Boost curves are also interesting to compare. Both make ~8.5psi but the curves are totally diffrent. Boost at 3200rpm is ~2.5psi for the Procharger vs 7.7psi for the roots. (That is assuming minimum boost was measured at 3200.) The graph seems to list AFR on the right but MAB said it was boost so they must have the graph mis labeled.

Cool data. It's easy to see why the roots is the prefered choice for towing applications!

TG

 

This is still not apples to apples, the info provided by ATI is testing NON IC Vortech against ATI's intercooled applications. There must be a reason why they did not publish their results of a comaparison of a intercooled Vortech or Paxton blower. What do they have to hide from?

 

2 votes and counting for the positive displacemnet blowers.

 

Not to mention that Vortec developed that standard, which has been heavily critisized by engineers on a number of levels. To quote from part of the standard.


Yeah...I would be pretty suspect as anyone else with a little mechanical/engineering knowledge should be.

 

Never mind, I missed a post. Sorry.

 

Hadn't noticed the misprint on the graph. We were measuring AFR with our own meters and not with the dyno setup so we could record AFR with all of the other engine data on the pulls. It should read boost pressure.