sciff5

iTrader: (1)

I am sure everyone has seen this vid as it has been posted before.

http://videos.streetfire.net/video/9...YNO_154043.htm

Its pretty damn impressive and I was just wondering if you guys think the R2300 is really going to surpass the twin screws out there on the market in terms of performance. I am playing with the idea of forced induction and just wanted to start a thread going about it because there doesnt seem to have been much talk about it thus far other than this vid.


Would like to get some opinions/info from some of the more knowledgable guys on the board.

OUTLAWZ RACING

iTrader: (9)

For what car?

sciff5

iTrader: (1)

In an ls1 rx7 but lets not get ahead of ourselves.. I just want to talk about the blower vs blower performance rather than application specific setups.

Killer_Z

iTrader: (1)

old vid, that engine was actually built for an SUV if i recall correctly. TVS is nice but still not a twinscrew,

sciff5

iTrader: (1)

Obviously its not a twin screw but why is a twin screw better?

Killer_Z

iTrader: (1)

the TVS max displacement is 2.3L twinscrews have larger displacement s/c. and a few other things i just cant think of.

but the TVS is a great step up from the factory heatons. so props to them on that. hell if someone makes a 2.3L TVS kit for the camaro i'll go for it

Hennytime

iTrader: (33)

i think it would fit in the camaro just fine. its only 11mm taller than the m112, so just a little more cutting and its there

sciff5

iTrader: (1)

I have yet to see any twin screw thats around 2.3L displcement on any engine produce numbers like the ones seen in the vid above, in fact most of the 2.8 KB Blowzillas I've seen usually dont make that sort of power.

DanO

yup.. you are exactly right..

there are a few reasons for this

the twin screw has one slow speed and one high speed rotor.. a typical 5/3 lobe configuration means that if the slow rotor is spinning 15krpm.. the fast one is at 25,000 rpm!! this is the limiting factor for speed/life of the screw type (i always hear of 20,000 rpm screw types.. but not one puts a warranty on it.. lol, i'll let you do the math for how fast the 3 lobe rotor is spinning.. yikes)

for the same bearing life rating.. you can spin the TVS to 25krpm.. and you'd be flowing ALOT more air becasue both rotors spin the same speed, which means both rotors hit their speed limits at the same time..

also, the TVS units are designed to flow alot of air for thier size.. If anyone knows how to actually read a performance map, you'd quickly see that the TVS units are surpassing the twin screw and will outflow it size for size..

sciff5

iTrader: (1)

I'm bumping this up because I want to hear some more info.

DeltaT

iTrader: (5)

It is hard to compare the TVS to the twinscrews of a similar size because Eaton only posts up performance maps for the 1900 and smaller, and when Lysholm post their comprehensive performance maps they display an overall adiabatic efficiency that includes drive power losses (hence their lower overall efficiency numbers). I'd like to see the same size TVS compete against the same size twinscrew, because no matter what you change in a Roots-type blower like the TVS, you will never achieve the same efficiencies as the twinscrew. The TVS is Eaton's most efficient series of air movers but the twinscrew compressors have them beat in overall efficiency and their ability to achieve higher pressure ratios comfortably. The fact that 1 twinscrew lobe spins faster than the TVS has not hurt their reliability, and if you were to spin a TVS to 25Krpm you would be moving a lot of hot air. Eaton has taken the Roots blower to its highest efficiencies ever, and made it quieter than people believed was possible, but you can't beat that internal compression cycle of the twinscrew.

GM would have specced the twinscrew (like the high-end Mercedes models) if it wasn't more expensive to produce. Once the aftermarket kicks in, you will see Whipple and Kenne Bell supercharger kits to replace the TVS blowers and people will buy them if they are seeking ultimate performance.

Jim

stevieturbo

More interesting.....is I wonder why the middle 2 headers start glowing much faster than the outer 2, and also take longer to stop glowing ?

jbusmc1986

iTrader: (1)

I was under the impression, that the tvs 2.3l was actually 4 screws stacked 2 high.... would that not actually make it a quad screw positive displacement blower rather than a conventional roots?

DeltaT

iTrader: (5)

Nope, it's just two 4-lobe rotors with a 160 degree twist to them, and it does not have any internal compression - it's simply a refined air mover:



Jim

jbusmc1986

iTrader: (1)

hmmmpfff.... well whadaya know. Learn something new everyday.

sciff5

iTrader: (1)

So then how can this unit produce HUGE power with very little displacement?

I keep hearing its not as efficient as a twin screw but then again I have yet to see any KB2.8s even producing these types of numbers and I think we all agree the little KB2.2 could never produce those numbers

How is this possible??? I just dont get it

Z06PSI

iTrader: (33)

So 850hp and 800 tq at the rear wheels is no where near that power huh?

sciff5

iTrader: (1)

Your right. The blower on your car was making those numbers on the last guys car. So the 2.8 can hang with the TVS R2300... but still if the twin screw is so much more efficient why dont you see kb units of similar size making the same power??

Dont get me wrong I've been leaning towards a twin screw or a single turbo, but I want to open this up for discussion to make sure I'm not making a mistake... yyah know missing out on some new profound technology or whatever.

Z06PSI

iTrader: (33)

Well Jeff on that run was at 19 psi. The blower is capable of 25 and above so we will see. I don't think the KB max has been found yet but I would assume that TVS was maxed. The biggest problem with the KB setup I am going to run into will be the intake going into the screw. I see that being the bottle neck but that is a Corvette specific problem.

JBrady

This brings up great questions. I have been a long time supporter of high efficiency compressors such as turbos and screws. I even brought a PSI screw to C&G Marine for dyno testing on off shore power boat racing engines way back in 1991.

That said just exactly WHY is there a difference in efficiency? It really comes down to how much friction and bypass are occuring in the "system". These TVS units look to be sealing VERY well and are moving the air into the manifold very smoothly and hence with surprisingly good efficiency numbers.

The argument that one is a pump (roots types) and the other is a "true" compressor (screw) because it makes boost internally is IMO really semantics. These TVS units are topping 75% adiabatic efficiency. If they are as durable as previous Eaton units this will make a GREAT street option. Other than screws nothing will give the range from off idle to redline that is possible here. I look forward to the screw vs TVS match-ups

With the ZR1 unit having a front intake and drive (and possibly the CTS-V as well ) the aftermarket applications are very appealing.