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Discussion Starter #42
screw-type

The Lysolm is one of many screw type superchager. Thing of it as a roots with the blower vanes twisted into dual interlocking screws. Whipple makes one etc. etc. They don't generate the heat of a roots, and they provide some boost gain like a centrifugal, which really helps efficiency. On Mustang Cobras, just replacing the factory eaton with the same pressure level whipple is worth about 40HP. When the eaton runs out of gas, the whipple is able to drive that car to 600HP with higher and higher boost.
 

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Re: screw-type

fzust said:
[ On Mustang Cobras, just replacing the factory eaton with the same pressure level whipple is worth about 40HP. [/B]
Same boost should make same power increase .

Only the different air temperature because of less “Incredibly high adiabatic and volumetric efficiencies” may cause differences in power output. But I doubt that this will be as much as 40 HP.
 

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Superchargers can take dozens or even hundreds of horsepower to run.

Thus, if you can replace a supercharger with a different model that has less parasitic losses, then you can gain power, even without better air flow, more boost, etc.

In practice, I don't know how much of a difference a change can make.
 

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Discussion Starter #45
Re: Re: screw-type

Ruediger said:
Same boost should make same power increase .

No. Boost is a measure of pressure, not air mass. If the Roots heats the air alot more while compressing it, 8psi at 220F will create far less power than 8psi at 140F since the air mass is much lower in the second-case.
 

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Re: Re: Re: screw-type

fzust said:
No. Boost is a measure of pressure, not air mass.
Let me propose the following compromise:

For more power at the wheels you have to “induce” or better to “force” more oxygen into the combustion chambers and / or make these chambers bigger but this will result in a heavy and slowly rotating monster engine. (Elephants normally live longer than mice)

And also such forcing machines called compressors or blowers are more or less effective.

Mechanically driven superchargers consume precious crankshaft power. Therefore it is important that they are even more effective than exhaust gas driven centrifugal compressors, which only are an obstacle in the exhaust manifold (and cost some power output because of this, too.)

And: Lysholm type blowers amongst them are said to be more effective than Roots type blowers.

Ineffective blowers consume more power to produce heat by friction. Heat is unwanted because it deludes or should I better write expands the oxygen concentration and it is always bad for an engine which better should be cooled to live longer.

Sorry I forgot to see the typical differences in mechanical friction. But I am very sure that the belt drives and or the bearings of Lysholm and Eaton Blowers are not so much different in design to cause such a difference of 40 HP. Even for a monster engine as you have in this Mustang this figure must be too high.
The engine of my first car- an old VW Beatle I drove when studying in Berlin - had an engine, which made less than 40 HP and consumed more fuel than my early120 PS - Rover-Elise (before I started modifying it)

That `s the technical progress.
 

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No offense but this argument is older than dirt. :(


Any fresh ideas? I personally will be toying with turbochargers, I think Corky would agree with me, in fact I may give him a call. To those going on about turbo lag, clearly you've never driven a car with a properly sized turbo.

For the time being though, Im going to sit tight and wait to get the car.
 

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Discussion Starter #48
Re: Re: Re: Re: screw-type

Ruediger said:
Let me propose the following compromise:

For more power at the wheels you have to “induce” or better to “force” more oxygen into the combustion chambers and / or make these chambers bigger but this will result in a heavy and slowly rotating monster engine. (Elephants normally live longer than mice)

>Parrots live longer than elephants....oops.

And also such forcing machines called compressors or blowers are more or less effective.

Mechanically driven superchargers consume precious crankshaft power. Therefore it is important that they are even more effective than exhaust gas driven centrifugal compressors, which only are an obstacle in the exhaust manifold (and cost some power output because of this, too.)

> I was by no way trying to compare blowers to turbos. Turbos are way more efficient hands down. This is not because they scavange pressure from the exhaust gases, but rather they scavange the energy of the exhaust gases in the form of heat. As you say the exhaust gas back pressure is minimal.

And: Lysholm type blowers amongst them are said to be more effective than Roots type blowers.

Sorry I forgot to see the typical differences in mechanical friction. But I am very sure that the belt drives and or the bearings of Lysholm and Eaton Blowers are not so much different in design to cause such a difference of 40 HP. Even for a monster engine as you have in this Mustang this figure must be too high.
The engine of my first car- an old VW Beatle I drove when studying in Berlin - had an engine, which made less than 40 HP and consumed more fuel than my early120 PS - Rover-Elise (before I started modifying it)

> That's true, it is around 26HP difference at 11.6psi according to the Kenne bell website. I was quoting the 40HP just by switching blowers on the 2004 Cobra. Some of this is mechanical, some is thermal efficiency.

That `s the technical progress.
Agreed.
 

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Been driving a car design with the ct26 turbo (91MR2) for 14 years. Have been running between 9-14psi. Lag isn't bad & you adjust to the non-linear power delivery. But am looking forward to the smooth NA power of the Elise, it's fast enough for me. FI isn't wroth the cost or hassle. I'm sure others will have fun with it & it will be interesting to see what they can do.
 

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OneFastMiata said:
-----Any fresh ideas? I personally will be toying with turbochargers, ---

My MX 5 - you call it Miata - also got an exhaust gas driven turbocharger. And even there under the FRONT hood this red glowing device caused me some problems when driving full power for a longer time than you normally can dare to go because of the general speed limits you have over there.

Toying around with such item behind there in Elise ´s engine bay close to its fuel tank is not very funny as you can hear or read from Rover- Elise owners who got it installed by Thielert .

In case you want to gain your own experiences you should provide also some forced ventilation system for the engine bay. This may be advisable even when installing a powerfull supercharged engine because the extra horses reaching the wheels always produce some extra heat in the stable they come from. and this heat must be removed properly from there or you will smell very soon that something is wrong behind your back.
 

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turbocharging the Elise has not been very popular in the UK. I think its down to 2 reasons - heat and lag.

the extra heat generated is hard to get rid of in such a small engine bay and any lag is noticable and IMHO does not suit this type of car.

Supercharging is the way to go if you want forced induction in an Elise...the headline power figures may not be so great but the increase in torque transforms the car.

However after seeing the Blitz kit in a Celica, I dont think it will fit in an Elise at all - what we need is for someone to develop a kit specifically for the Elise...or go down the honda K20+supercharger route as per Prototype Racing
 

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Ruediger said:
OneFastMiata said:
-----Any fresh ideas? I personally will be toying with turbochargers, ---

My MX 5 - you call it Miata - also got an exhaust gas driven turbocharger. And even there under the FRONT hood this red glowing device caused me some problems when driving full power for a longer time than you normally can dare to go because of the general speed limits you have over there.

Toying around with such item behind there in Elise ´s engine bay close to its fuel tank is not very funny as you can hear or read from Rover- Elise owners who got it installed by Thielert .

In case you want to gain your own experiences you should provide also some forced ventilation system for the engine bay. This may be advisable even when installing a powerfull supercharged engine because the extra horses reaching the wheels always produce some extra heat in the stable they come from. and this heat must be removed properly from there or you will smell very soon that something is wrong behind your back.
Im afraid Im not understanding quite what you're saying.

Your miata got an exhaust gas driven turbo and it glows?

Ive driven under boost on LONG stretches of fast interstate. No troubles. Ive also driven track days, no worries. No, I dont drive extended periods of time in full boost,you're really not supposed to. Once you get up to speed you really dont need to be sitting in boost constantly. I dont need to do it with my miata's on the interstate or the track and I dont suspect I would be doing that in an elise either.

In case I want to gain experiences?

I have 3 turbo miatas and 3 turbo RX7's all done in my home garage, all full custom and all pushing considerably more hp than most turbo miatas/Rx7's, in fact Im quite well known for them, and none of them have experience any problems in this respect. Ive also messed around with putting giant turbo's and Electromotives on Mr2 turbo's with engine bays very similiar to the Elise without problems. Not discounting what you're saying, just saying that Im very familiar with turbo miatas and turbocharging in general and ive been told that " that isnt possible" before and now what wasnt possible is becoming the norm.

In short, everyone has an opinion on what is best. You go your way and I'll go mine. :) Rest assured though, Im fairly adept at this by now and will certainly do my best not to spontaneously combust. :D
 
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