S/C Efficiency at 5psi...

Now another thing that hasn't been discussed is stock camshaft duration and valve spring closing strength.
Has anyone to date done the math on a stock cam and valve springs verses valve size?


Jeff

 

That way Jason will be able to beat me by TWO (2) car lengths in the quarter...right??? LOL

 

After I re-read this, I felt it needed more clarification.

Less effecient superchargers alone can cause the post supercharger temperature to be hotter than more effecient superchargers. Therefore, when you compare two at a constant 5 lbs boost, the two intake manifold charge temperatures can be different. Then, based on density, the mass flow for one can be different from the other. Then, if you tune both to a constant A/F, the one with more air mass will get more fuel and more power.

All wrapped up in this is the intercooler effectiveness. Some of the roots type blowers may not get as much cooling as the centrifugal type...because they are placed right on the intake manifold. These would get significantly less mass air flow than the centrifugal type with a properly placed intercooler.

Keith

 

A great test would be for you to take out the predator totally and then run him. This would give us a better baseline test.

 

I'm not so sure. At higher RPM 5lbs of boost is still 5lbs of boost regardless of the flow. It would be harder to get 5lbs of boost at higher flow but if you do then the gain would be relatively as significant as at lower RPMs. What JMatt explained is that 150 shot (fixed quantity of NO2) has less effect at higher RPMs due to the fact that there is a greater amount of air that the fixed amount of NO2 is being sprayed into. 5lbs of boost is not dependent on the amount of air. It's just that whatever amount of air is being delivered at 5lbs of pressure.

I agree with that (but not for that reason). Less torque, less stress.

Ha, cavitation, never thought of that. I'm assuming it's only the centrifiguls that spin fast enough to generate cavitation? haha, does it sound like you've blown up your blower when that happens?

Eh... Now that we know the difference between the different types of blowers we know that comparing from a roll probably gave Jason an advantage over starting from a dig.

And low isn't where a centrifigul does much.

I don't buy this. I guess it would depend on where you have your boost gauge, but if it's at or in the manifold then 5lbs is 5lbs.

The warranty is only on the blower right?. You're not going to hurt a blower with a tune. So if your blower goes bad it won't be because you have a tune. Blower goes bad, you put your vortech tune back in and go for warranty... not that I'd ever suggest that.

Is it? Is the PERCENTAGE of gain from 5lbs of boost at 77F much different than the PERCENTAGE of gain from 5lbs of boost at 120F?

Maybe not. See above. You guys may have to start doing comparisons in the half instead of quarter.

 

I think the diff between a twin screw and a centrifugal is the actual "Lag" of the centrifugal in making boost.

Maybe some info is here...
http://www.superchevy.com/technical/engines_drivetrain/induction_poweradders/0510sc_theory/index.html

And here...
http://www.whipplesuperchargers.com/faq.asp?faqID=35#35

And the whole story but not neccessarily the answer..
http://auto.howstuffworks.com/supercharger1.htm

 

WOW! This thread could go on forever and still everyone is going to vary in one thing or another. PUCK IT, I'm going to trade my car in for a Scion. I could still beat Rick by a car length........................HAHAHAHAHAHAHAHA

Thanks everyone for the information:dumb:

 

I think it's a lot more than that. Here is the most excellent link that Hal pointed us to in a different thread.

http://www.superchargersonline.com/content.asp?ID=76

 

Here is some great very techincal info on S/C efficiency, Vortech Centri in particular
http://www.vortechsuperchargers.com/download.php?dir=pdf/papers&file=efficiency_paper.pdf

To put things in an easy perspective
Centris (Vortech, Paxton, Procharger etc) build power and boost as engine RPM's increase, more power and boost is available at higher RPM's and they tend to be easier on components because this is how the motor natually build power. Centris tend to have lower torque numbers down low, but tend to have higher overall HP #'s when compared to a similar twin screw/roots. Obviuosly I am making broad statements here, there are exceptions to every rule.

Roots or Twin Screw Top mount style Superchargers ( Kenne Bell, Whipple, Eaton, RDP etc) tend to have more toque down low but less top end. They also have instant boost...which is fun on the street, but are also harder on components, and typically not as good for the drag strip. Case in point...go to any NMRA or NMCA Drag racing event and try to find any top cars in almost any class running roots/twin screws...and you will not...there are a few but they are typically not the competitve cars, they are all Centirs or Turbos. In fact the lone Kenne Bell Mustang in Modular Muscle was recently contemplating switching to Centri.

Both styles will produce plenty of power and torque. It really depends what your goal for the car is. Are you planning on building a motor, are you planning on drag racing, or just a fun street/strip car? Is the car a daily driver or a pleasure cruiser? All of these factors weigh in when choosing a blower type. We have had experiences with Vortech/Paxton and Procharger on the Centri Side, and Saleen, Roush and Whipple on the Roots/TwinScrew Side. All are good products, it just depends what you want.

 

You know it will be a lot more than 2 with a good performance tune. You sure are running your mouth a lot about this. Why don't you come try mine when its back, I'll even leave the Vortech tune in it.:grin:

 

Running other stock SRT's and even a Jeep, I can tell you we pull a lot more on a stock SRT than one with a Pred tune, exhaust, etc. I'm liking the Vortech more and more the more I drive it, just wish we could at least change shift points and a few more things.

 

I'm sure we will find a way to change things down the road................

 

Yep... in due time... and a good tuner that won't take my first born...Lol!

 

talk to steve at rdp

 

Exactly my point Dave which was Jason's and Rick's too ... you'd have thought Jason's car would have pulled more than just 1 car on Rick's.

NICE post Kris!!

 

Thanks bro, people are working on this right now! I will requote John's, "TIME WILL TELL"!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!:whistle:

 

Actually I wouldnt think that the 30 hp diff would have been more then 1 car...especially with Jason losing a bit of power lower. He is having to play catch up till his boost puts him over Ricks curve. Which since I havent looked at both can only assume that rick is making more power below 3500 or so

 

I think thats where the Drew's comment originated.

 

Another potentially exciting technical thread falls in the crapper with useless I need a better tune comments .............:help:fftopic:

 

Yes, Sir I would agree with that.........................................:cry: