moregrip

iTrader: (8)

the above question was leading somewhere, but for the life of me I can't remember where, ah well, I'm getting older everyday, suffice to say, I agree with flyer that without IC'ing the whipple/KB are better left on the table.

Flyer

iTrader: (1)

I'm saying that with the bigger rotors, there's more area to provide pressure, so less overall heat. The compresor wouldn't have to exert as much energy, and we all know energy is what creates heat.

I still think though, with the advantage of having an intercooler, the improved roots will come out on top.

Mr. Sandog

Well, I'm one of those people who, if he hasn't any experience with something, isn't going to venture an opinion on the matter. I will make an observation, however - people who have Whipples seem to be quite happy with them. Additionally, I would consider one in the future if the price was right.

David Cairns

The act of compressing air, no matter how you go about it, will produce hotter air. That is just basic physics, and that is one of the reasons they make intercoolers. On top of the heat generated by the act of compression is the extra heat generated by the process used. This is commonly referred to as adiabatic efficiency. A turbo or centrifugal blower scores well in this department, followed by the Lysholm and a roots style scores worst here. In my book, the ideal system would be a Radix with a Lysholm compressor on top. Rather like the Kenne Bell Blowzilla upgrade for the Ford Lightnings, which replaces the stock Eaton roots type with a Kenne Bell Lysholm type compressor of higher capacity.
If you live where the weather gets hot, you will want an intercooler, no matter what kind of blower you have. There is no getting around the fact that hot weather hurts the performance of forced induction unless you can cool down the air.

moregrip

iTrader: (8)

The twin-screw design is the one that compresses air (specifically between its rotors blades), and the Roots type Blows (charge air compression occurs outside the supercharger)(ala Blower). Both produce heat(agreed). The Roots is the least effecient, no doubt, however, we are talking modified roots here, and intercooled at that, the effeciency is greatly increased and more consistant than the non IC'ed twin-screw. Now, an IC'd twin screw, as you've stated, will produce more boost and with better efficiency, however, the merits of the modified roots still outweigh the benefits of the twin-screw in a daily driven vehicle, IMO. One of the problems with a non IC'd system on the street is the inconsistency of efficiency specific to use and temp, obviously the intercooler not only increases performance but also keeps said performance more consistant over varying conditions. The specific merits that lend to the modified roots street dominance are, 100,000 mile service life, thats what Eaton rotors give everyone, no other manufactuer, that I know of, can say this. Also, the off idle boost is second to none, although the whipple is close, is has to overcome its biggest negative which is any "off boost" condition. Read this: "The Twin Screw is still compressing air internally even during non-boost conditions and this generates heat and has more parasitic drag on the engine during non-boost even with a bypass valve". With the Lysholm where the air is compressed inside the blower and then decompresses as it leaves the blower and enters the plenum, the advantage with the modified roots type is that it has less parasitic drag on the engine when boost is not needed, On a daily driver where we spend more than half our time in a non boosted state, the twin-screw will always produce more heat in this environment, especially a non IC'd twin-screw. These are just the facts folks.
That said, if less than a daily driver is your goal, or your idea of a daily driver is somewhat less reliable, then your options open up quite a bit.

The End

BlownChevy

iTrader: (20)

These were some facts that I was going to add. Good Job Grippy!

David Cairns

Looks like we largely agree (look at what is on top of my engine)

It has been a while since I did my supercharger research, but as I recall, Whipple uses a bypass system, just like Magnuson, for non-boosted conditions. I don't remember about Kenne Bell.

moregrip

iTrader: (8)

absolutely, didn't mean to sound as if we didn't

TieRod

Hey Grippy it kinda hard to compress air when their's no air to compress because the throttle is closed. If would like an example go fire up you shop vac. Put your hand over the end, see how the motor speeds up from the reduced load. Also with a bigger compressor it does make less heat but at the sacrifice of low RPM boost. If you would like proof I have vid of a friends car it has a 302 with a 177 blower it makes 3psi off idle and max's at 12psi 5500rpm.

Mr. Sandog

I feel like I am reading an academic journal. :yawn: Since we're all pontificating here, I guess I'll add my $.02.

If Whipple made a 2.2L kit with 42# injectors, intercooler, etc., that mounted on top like the Radix, (a la Starr Performance), it would be superior to the Radix, simply because of increased efficiency and/in compression. The Whipple has a bypass valve as well - but even if it didn't, any 'increased heat' would be so miniscule as to be irrelevant.

Liter per liter, the Lysolm twin screw is simply a superior technology to the modified roots Radix. I really don't know why, but some people seem to have a huge problem acknowledging this.

The Radix, on the other hand, has the benefits of: (1) Intercooled, (2) Complete kit (3) Price, (4) Ease of installation, etc. It also has a great company standing behind it with a fantastic warranty and excellent customer support. There are no denying the benefits of the Radix - there are so many benefits, in fact, that they cannot be overlooked. After all, it is what I have on top of my motor. But engineering-wise, design-wise, and efficiency-wise, the Radix loses to the Lysolm.

Unless and until there is a manifold-mounted Whipple kit for under $10K (which is what the Starr Performance unit costs), the Radix will continue to win customers hand over fist above any Whipple or Kenne Bell unit. This circumstance, however, does not negate the fact that the Lysolm is superior technology, even if we don't get to benefit from it at this time.