Twin Superchargers?

Euphoric306 · Sep 13, 2005

wtf... 8 turbos, thats like a waste, he should've stuck to four and given me the other four hehe

i know there's a new chrysler 4-12 with 4 turbos on a v12, but it was just a concept car last i heard

BLAH

tjm73 · Sep 13, 2005

bluevenom867 said:
You see this one car,guy put 8 turbos on it.I think it was a SBC in a 55-57 Chevy,but I could be wrong.It was in a hot rod mag or something.

You are correct. It was in Hot Rod.

Gearbanger 101 · Sep 13, 2005

Here are the numbers provided by the Eaton MP90 and M112 for your comparison....

MP90

MP112

If you'll notice, Kenne Bell doesn't make it a practice to promote these numbers, they only state that at "peek" levels their efficiency numbers are better....which is true. But that's now the point I was debating. I've been able to piece together bits of information with regards to the twin screw efficiency rating and all data I’ve collected shows them being of less efficiency at lower boost and blower RPM levels (this due mainly to the twin screw's internal compression design itself, which is constantly squeezing the air charge...even in unboosted conditions). Yes, the bypass valve does help to lower temperatures, but only to an extent.

The modern Roots style blower utilizes a bypass valve as well, but without continuously squeezing and compressing the incoming air which in the end results is endowed with a cooler charge. The screws efficiency increases as blower RPM increases. In the 1.7's case the blower doesn't reach that magical 90% peek efficiency Kenne Bell advertises until well into the 11-13psi range where it has now reached the limits of the blower. But at lesser levels (in the 2-6psi levels) their efficiency can fall into the lower 30% range. The temperatures at this level are not enough at this point to warrant the used of an after cooler, but in the same respect, the air temperatures are still higher by comparison to the Eaton in relation to the volume of air produced. The reason it's tolerable after 6psi and up to peek levels, is because of the after cooler. Where in the Roots case, the blower reaches peek efficiency earlier, but drops off like a stone soon after and the cooler is needed to keep temperatures under control as it continues to produce airflow beyond its upper levels of efficiency.

In basic terms, the Eaton starts off cooler and gradually increases in temperature until peek levels (which are of course at lower levels than the screw) where ACT's begins to soon increase dramatically and the blower has all but written itself off. The Screw compressor starts off at higher ACT's (by comparison) because of its internal method of compression until it begins to near peek efficiency rating where the temperatures begin to normalize again. The after cooler is needed before and during this time regardless and is what keeps these temperatures under control in the mid-levels.

All this of course is related to the over all volume of air being produced. ACT's are always climbing with either blower, this is inevitable, but in relation the rate in which they climb differs between the two methods.

In the same respect, I’d be interested to see (if someone is able to find it) more advertised data with regards to a twin screw showing superiority in the lower levels as far as "over all" efficiency is concerned. I’ve been able to piece together a little of it over the last couple of years that proves to the contrary, but in general there doesn’t seem to be a lot of it floating around and all that the companies making these blower like to promote in the advertisement propaganda are peek levels or horsepower numbers. You never seem to see all the data in between.

Look Its Aaron · Sep 13, 2005

Here is the car you guys are talking about:

http://www.lateral-g.org/sandlin/

QDRHRSE · Sep 13, 2005

Paxton has been doing twin blower kits for decades. On of my friend's family tried to buy a Cobra (Shelby) that was built for Bill Cosby way back in the day. It came with the 427 and the twin paxtons- from Shelby!!! At the time, they couldn't come up with the $200,000 for the car. It's probably worth 15-20 X that now.

Daggar · Sep 13, 2005

Gearbanger 101 said:
Here are the numbers provided by the Eaton MP90 and M112 for your comparison....

What have you found so far to compare this to? Anything from Whipple of KB? What I've seen and read so far has shown peak efficiency rates for the two (or 3) blowers in comparison being at different boost levels and displacement outputs. For example, peak effeciency for the Eaton comes allot sooner that it does for either of the twin screws. I think my question has allot more to do with overall effeciency of each type of blower vs. the HP output on the same engine combination. I haven't found anything yet that suggest the overall efficiency of an Eaton is better than that of a twin screw. What I have seen are various tests (including magazine articles) where twin screws produced better torque and HP numbers at equivalent boost levels to the Eaton. Is this not correct?

Gearbanger 101 · Sep 13, 2005

QDRHRSE said:
Paxton has been doing twin blower kits for decades. On of my friend's family tried to buy a Cobra (Shelby) that was built for Bill Cosby way back in the day. It came with the 427 and the twin paxtons- from Shelby!!! At the time, they couldn't come up with the $200,000 for the car. It's probably worth 15-20 X that now.

Check out the top pics of this post....
http://forums.stangnet.com/showpost.php?p=5475721&postcount=7

Daggar · Sep 13, 2005

Oops... took too long to update my post. The phone rang.

Gearbanger 101 · Sep 13, 2005

I didn't state that over all efficiency was better with the Eaton, only lower level efficiency.

The various tests article that I’ve seen printed aren't exactly objective by comparison. When most manufactures (save for Kenne Bell obviously) rate a blowers efficiency, they refer to the output of said unit alone, not the blower bolted to their particular brand of manifold, with their particular brand of inlet system, bolted to "X" car, with "X" amount of modifications. For one, the accompanying manifold the blower is saddled with has a huge effect on all characteristics. Take a look at the Saleen series IV and V kits. Both utilize screw compressors (Whipple) of the same design as Kenne Bell, but since the manifold and inlet design is inferior to the Kenne Bells, all other aspects (power output, flow potential, boost levels, discharge temperature) are affected....but not because the blower itself is any less efficient, but because the accompanying supporting parts are holding it back.

Also, not one article I've come across test any of the Positive Displacement blowers back to back in the 6psi, non intercooled range, nor do they run them in this range for any length of time. All I've seen plenty of tests where they've been pullied for 9lbs, 10lbs, 11lbs….even 20lbs of boost and run them a WOT on the dyno for a couple of seconds, then shut them down. This doesn't exactly mimic part throttle street operation that your average owner will see on a daily basis. I'll venture a guess and say full boost WOT applications only represents about 5-10% of normal driving.

If the Kenne Bell twin screws are so much greater at all levels of operation than all others, then why don’t they publish this data for all to see? It took me forever and dozens and dozens of searches through different sources to gather any data at all on them. Where are Kenne Bells hard figures stating volumetric efficiency, at a given level of boost or blower RPM, ACT’s at specific levels, horsepower required to support this level of airflow at these specific levels, etc, etc? Why do they not quote any specific figures in their sales propaganda, but instead make vague statements about superior efficiency backed with nothing more than an opinion based on their own views? I for one am all for Kenne Bell kits when looking to make high levels of power, where low end torque is still a concern, but I unlike some refuse to fall pray to creative sales pitches and self inflated opinion stated by one particular company about their product being “the best on the market”, just because they say so, when I’ve seen other tests that prove otherwise. I’m not questioning the ability of the kit itself, but their unproven claims of the power source behind it.

rowdie- stang · Sep 13, 2005

I dont have any pics but I have seen a 5.0 with a roots blower and a vortec on it

Daggar · Sep 13, 2005

Gearbanger 101 said:
I didn't state that over all efficiency was better with the Eaton, only lower level efficiency.

The various tests article that I’ve seen printed aren't exactly objective by comparison. When most manufactures (save for Kenne Bell obviously) rate a blowers efficiency, they refer to the output of said unit alone, not the blower bolted to their particular brand of manifold, with their particular brand of inlet system, bolted to "X" car, with "X" amount of modifications. For one, the accompanying manifold the blower is saddled with has a huge effect on all characteristics. Take a look at the Saleen series IV and V kits. Both utilize screw compressors (Whipple) of the same design as Kenne Bell, but since the manifold and inlet design is inferior to the Kenne Bells, all other aspects (power output, flow potential, boost levels, discharge temperature) are affected....but not because the blower itself is any less efficient, but because the accompanying supporting parts are holding it back.

Also, not one article I've come across test any of the Positive Displacement blowers back to back in the 6psi, non intercooled range, nor do they run them in this range for any length of time. All I've seen plenty of tests where they've been pullied for 9lbs, 10lbs, 11lbs….even 20lbs of boost and run them a WOT on the dyno for a couple of seconds, then shut them down. This doesn't exactly mimic part throttle street operation that your average owner will see on a daily basis. I'll venture a guess and say full boost WOT applications only represents about 5-10% of normal driving.

If the Kenne Bell twin screws are so much greater at all levels of operation than all others, then why don’t they publish this data for all to see? It took me forever and dozens and dozens of searches through different sources to gather any data at all on them. Where are Kenne Bells hard figures stating volumetric efficiency, at a given level of boost or blower RPM, ACT’s at specific levels, horsepower required to support this level of airflow at these specific levels, etc, etc? Why do they not quote any specific figures in their sales propaganda, but instead make vague statements about superior efficiency backed with nothing more than an opinion based on their own views? I for one am all for Kenne Bell kits when looking to make high levels of power, where low end torque is still a concern, but I unlike some refuse to fall pray to creative sales pitches and self inflated opinion stated by one particular company about their product being “the best on the market”, just because they say so, when I’ve seen other tests that prove otherwise. I’m not questioning the ability of the kit itself, but their unproven claims of the power source behind it.

Yeah, I get what you're saying about this company's claims and that company's claims all being one sided. It's similar to the great underdrive pulley debate and no dyno data to back up the 15 HP gain. Data at other than WOT for a Blowzilla would be difficult for the average shade tree mechanic to obtain (since the bypass is recirculating at just about any power setting below WOT). I have seen reference in other forums about the 2.2L seeing inlet tempuratures as high as 190 while sitting in traffic after the motor was good and warmed. Like you, I've not seen any charts or graphs showing what discharge temps are across the RPM range starting at idle. They've all been power runs.

I went to the SAE website and they seem to have tested and written the kinds of data that you're talking about but they also want a credit card number and $50 for the talking papers. Sooner or later someone will post those numbers in a public atricle, I would think.

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Your car looks like it came straight from Mexico.

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