30 replies to this topic

[LMP1]

Sorry for the stupid question, i have a friend who says that he can find opcon twin screw sc's

 

relatively cheap. I will look into it, but i d like to ask you first if you know anything about them.

 

I found that:

 

 http://www.not2fast....s/autorotor.pdf

 

if its of any help

 

(i think i ll go sc... after many changes of mind  )

[Scuffers]

As twin-screw compressors go, Opcon are one of the quality manufactuers.

 

HOWEVER!

 

great as twin screws are, they do have downsides, for a road car that spend most of it;s time off-boost, they are a much bigger parasitic drag than the TVS.

 

where they 'win' is that in high boost applications, they are more adiabatic efficient in theory as they are a compressor, not a pump.

 

the reality though is that unless you're planning on more than ~1.5 Bar boost, the TVS wins hands down, (before the TVS they probably had a better chance )

 

 

[LMP1]

is that boost pressure (that TVS is preferable) ok for a little less than 400hp [where the liners give up (z22se/z20net variant)]? 

 

400hp include the parasitic loses so around 350 at the fly

 

Thank you for your help!!

[Scuffers]

Not sure whatyour getting at? Current TVS cars are making ~320 at the wheels with ~ 220Kpa (absolute)...

[LMP1]

Current TVS cars are making ~320 at the wheels with ~ 220Kpa (absolute)...

 

 

 thanks!!

 

*absolute means 1.2 bar + 1 bar the atmosheric?

[techieboy]

Looks very similar to the Lysholm chargers that were fitted to the very early VX/Speedster conversions. Don't know if they're related in some way?

[slindborg]

Also, boost is merely a measure of how bad the engine is at breathing

[Scuffers]

Looks very similar to the Lysholm chargers that were fitted to the very early VX/Speedster conversions. Don't know if they're related in some way?

they are, Opcon brought Lysholm (and have now sold them again!)    

Also, boost is merely a measure of how bad the engine is at breathing

very much so, in an ideal world, you can get the airflow without the boost for example, Lee's car usinging ~220 Kpa to make ~330, a K20'ed Exige is making 300 with 158Kpa (on less CC's of engine and a less efficient M62).

[LMP1]

so head port and polish will improve performance for less boost

[slindborg]

so head port and polish will improve performance for less boost

depends who does it and what is done...

 

because most engine work isnt done in isolation its very hard to dtermine real gains from some things that seem popular to mod.

 

e.g.

The head might actually flow well enough to make the power but the inlet manifold could be a bottleneck, so headwork wouldnt improve anything other than lightening your wallet.

[LMP1]

i have this manifold. Is it ok?

[slindborg]

Only if you purchased it second hand for sod all. Dilbert tuning parts are the biggest con going imho

[Scuffers]

i have this manifold. Is it ok?

how's that work with the supercharger?

[Stig_1911]

If you are using the dilbert manifold, think you have to go with rotrex chargers...

[smiley]

Rotrex users can just channel it back into a plastic 2.4 manifold.

Too bad GM bumped up the price of it to silly level.

[Scuffers]

If you are using the dilbert manifold, think you have to go with rotrex chargers...

Pikey rubish option

[slindborg]

Pikey??!?!?!? they are far from cheap

[Scuffers]

Pikey??!?!?!? they are far from cheap

Maybe so, but they are still a pikey POS.

[smiley]

It performed pretty well when comparing it to a harroped one over here on the dyno.

Slightly later start in torque climb, but then comparable way up.

 

[Nev]

Hi LMP1, If you want to get more power for less boost you need to think about getting more air into and out of your engine with less resistance. This can be done in many ways. In short, you need to think (from first principles) about how the air travels from the atmosphere (just before the air-box) to atmosphere (just after the tailpipes). Eliminating restrictions to this airflow is the fundamental concept of tuning the engine, as after all it is just a large "air processing machine". Hope that helps.