quad rotor

[HEAVYBOAT]

Originally posted by Slyder
I understand all of the theories that are in play here, however, there is no way that you are ever going to be able to compare these two combinations.
The only thing that would make sense would be to take that big ol' FORD, dyno the hell out of it w/the 8:71, then bolt on the Quad rotor at the same session and see what it would do. Same carbs, etc........and since that isn't going to happen, you guys can flap your gums, or beat up your fingers on the keyboards and talk about how we are trying to learn something here..........
The bottom line, the roots blower is not as efficient.....by how much we will never know unless we back to back.
Paul:wink:
Do you know what Slyder,your post just supports my argument. If these combos are so close together that a carb or the bumpstick can change the comparison drastically from one engine to another then the whipple CANT be that superior then they want to make it seem.. Don’t get me wrong, I’m just like everyone else when I read articles from people like Dustin about this product and its advantages. I’m always so dam impressed after reading a few of his paragraphs that I want to bolt a quad rotor on my caravan and go beat John Force.
But.... when the smoke clears off tires on my mini van , I get a reality check in a hurry and realize that I’m not THAT much faster then my neighbour in his Aerostar with his 1970 roots driven Ford. So maybe… just maybe, me and my Caravan should pipe down just a little bit.

[superdave013]

Heavyboat, I'm not knocking you or your numbers.
I do understand the reason why they correct them. I also know that lots of dyno shops are in the biz of selling hp and making happy customers.
Numbers can be fudged very easy to make someone happy. It happens all the time. Trust me, I ran test equipment for many years for a major aerospace company and have seen it happen first hand.
I would think that dyno time should be used as tuning time. It's not the max number that really matters. It's starting out and getting a base point. Making changes and seeing if you are going forwards or backwards. We all know that you can make major improvements by playing with what seems to some as small things.
Like someone else said. The only way to really know 100% for sure what's better and by how much would be to do back to back test on the same dyno with the same engine under the same conditions.
But you did bring up a great point. I do know for a fact that Info's #'s are not corrected. They are what it ran that day in that room. Well, at least that's what he said. So, you guys have been going back and forth for 4 pages comparing apples to oranges.

[superdave013]

that was a quick edit

[Infomaniac]

Well SuperDave.
Those numbers are not the fudged corrected numbers.
Which is easy to do. That dyno is not as Generous as others.
That brings up some post history that I generally avoid. Not entirely avoidable because I did say it.
Thanks for the backup.

[HEAVYBOAT]

I agree with you on how easy it would be to fudge a number. And that is the exact reason why my builder is one of the most respected builders around. His numbers are conservative and his dyno is known for being tight and not giving out the good numbers very easily.
Besides I am a racer, who knows how much power it takes to get the job done. And he was bang on with the dyno stats. A dyno that lies is a dyno that will go out of business long term.
Info, where is this dyno you used elevation wise?

[superdave013]

Originally posted by Infomaniac
Well SuperDave.
Those numbers are not the fudged corrected numbers.
Which is easy to do. That dyno is not as Generous as others.
That brings up some post history that I generally avoid. Not entirely avoidable because I did say it.
Thanks for the backup.
speaking of fudge. A co workers wife sent a bunch of killer fudge to the shop today. I ate so much of that shit that I don't feel to well right now. She said she will bring a bunch of cookies tomorrow. I'm bringing a qt of milk.

[superdave013]

Heavy, You sure do sound like you know your shit.
What do you race?
You know what's funny? Out here it seems the "hot dynos" are the ones that get all the work. People go to Brummetts and get their feelings hurt and then go back to the "hot one". lol

[Infomaniac]

Originally posted by HEAVYBOAT
I agree with you on how easy it would be to fudge a number.
A dyno that lies is a dyno that will go out of business long term.
Info, where is this dyno you used elevation wise?
Not unless the rest of them fall in line to stay in business.
Tulsa elevation is 680'

[Whipple Charged]

Heavyboat,
It's pretty simple, the combo of lower temp and lower parasatic losses can be anywhere from 0-800hp depending on the application. The higher the boost, the more beneficial the screw becomes. You can't give exact numbers because every application is different. As I said, on the 900SC, it was over 100hp and that was the combo of lower parasatic losses and cooler temps. This was intercooled, it's more dramatic unintercooled because the intercooler effectiveness is higher with the increased temps.
Take this to heart, any motor where somebody wanted to compare a roots (any brand) to a screw, with equal sizing on both, the screw will make noticiably more hp from 2psi and above. Torque will be better virtually everywhere, especially at lower speeds.
What your missing is that the roots is no comparison to the screw in the higher boost levels. The airloc BDS? C'mon, your not grasping the concept. This makes the roots better at one PSI and worse at another. Do you think there actually somehow magically locking the air? No, there controling where the air discharges and there trying to tune the outlet so you would only leak air back into the case in the smaller area. As I said, a large majority of the rotors are not passing air, with those exposed to the intake, they are acceptable to leak more. But at the same time, if this is not perfected to the airflow requirement, you will restrict the outlet and actually defeat the purpose. I've worked with roots for years and even worked on developing one for racing but decided against it. The roots can be improved, leaps and bounds, what your talking about is still about 30 years behind in technology. That latest concept has been done by others.
Now you keep refering to your motor, the fact is this, there is no such thing as a "tight" dyno. An engine creates a certain amount of energy or power, any number a measuring device gives other than what is truly being produced is whats known as "inaccurate." You should realize that you will never run your boat from 3000rpm to 6000rpm in 5 to 10 seconds under full load. If you think and even rec'd a dyno sheet that says 1175hp on your engine, a screw compressor motor with 100 less hp will still propel the boat faster. It will hold the HP within a few % while the roots will continue to fall. Put your hand on the roots after a run and then put your hand on a screw. Then tell me which is producing cooler air. Your getting false information, hold the motor at WOT for 10 minutes, see what it does. This is some of the durability studies we do.
If you still can't see the writing on the wall, Mercury's new 4 stroke outboards have SC's, what type do you think those utilize? How about some other new packages? You'll see in Feb. at the Miami boat show that there will be no question. Then there's Ford, the new GT has the 2.3L sc that we utilize, next years Lighting, then the Cobra are following. Mercedes has been switching all their SC's over the past 3 years to screw compressors. Theres plenty more to come.
Also, if starting from scratch, the quad is well worth the extra $1000-3000. Especially when you consider we use the only proper material for intercoolers, this technology is more expensive but well worth it.
If you have any questions still, call Paul Pfaff Racing Engines, Gary Teague @ GT Performance, Bob Teague @ Teague Custom Marine, Lary Peto @ Larry's Engine and Marine or Ed @ Sterling Performance and they'll tell you the same thing.
Thanks,
Dustin

[HEAVYBOAT]

Originally posted by Infomaniac
Not unless the rest of them fall in line to stay in business.
Tulsa elevation is 680'
680 feet!! What a luxury, you can fish right off your front porch
This "NOT" correcting hp story is starting to make a little more sense now. That chuckle just made my day.