Hi people,
I've been pretty well googled as I can find some of my post referred to in this thread
This seems to be an interesting discussion about the basic considerations when making the choice SC vs turbo.
Which SC items are easily available is a point that to a large extent influences the choice of the SC. We'll have to do with what's around.
That's how I got started with this project. A friend came to me and asked Can you do something with a kompressor from a MB engine?
He knew that in such case I can not refuse. If tomorrow he pops up with an aircraft engine, next year it will have four wheels
During the years before I have been playing with turbo's and I am convinced that in a good designed setup they are very reliable and efficient.
In the field of pure physics they are more efficient than any SC but this is not what we care about. An OEM engineer wants to design an engine with low consumption, we want a powerful car with a specific character (read: torque graph).
Both turbo and SC have their specific influence on the way power is developed by the engine. It's all about compromise. We choose for the SC.
There are a couple of things mentioned in this thread to which I would like to add my 2p.
- There is no turbo lag with a SC. There is SC lag instead
You can not deny the reaction times measured in my setup. I have a volume of roughly 10L between the SC and the intake valves. With an air/water IC integrated to the inlet plenum I guess you will noticeably decrease the lag effect caused. The same applies to a turbo setup but don't tell anybody, they all think it's turbo lag
I used the electric bypass valve just because it was there and I found it a challenge. From open to close it takes 0.215sec. This adds to the other lag causes. I have no idea how a vacuum actuated valve performs but please let me know when you measured it
- One path I haven't seen here is to mount the SC under the inlet plenum. It's feasible if you move the alternator and the oil filter-heat exchanger combo. That is the way I want to go for my new setup.
- If you insist on keeping the A/C, keep in mind that this stresses the importance of the idle regulation AAC and FICD valves. This could get tricky when using custom plenums and/or installing the TB upstream of the SC.
- The bypass valve. The M62 mentioned has an electric clutch. I guess it should have somekind of a bypass as well because the engine will not be able to breath very well through the SC which is at standstill. I think that in this case it could be a non-return style valve which is rather simple in construction but mind you sometimes the more easy it looks, the more difficult it gets. If this valve is doing nothing more than opening with the flow and closing with the reverse pressure difference, the SC kick-in will be very noticeable. If you can live with that feeling, you could as well control the electric valve of the M45 with a switch or from a TPS threshold. That will be much more simple that my attempt to control the pressure build-up.
- If this
http://victorylibrary.com/graphics/Eaton-M62-1.JPG is the M62 we're all talk about it seems to me that its pulley has a larger diameter than the one on the M45. You will need a larger diameter pulley on the crankshaft to make it spin as fast as the others then.
I know you don't need the M62 to spin as fast as the M45 to achieve the same mass flow but make sure you manage to get where you want.
- The crank pulley is one of the main issues. I've seen only one build of aftermarket pulley for the CA18DET and that was without torsional vibration damper.
On one of the boards someone was using an undamped aftermarket pulley. I can't find it right now but it would be useful to have feedback about this.
I'm using the stock pulley where the middle (A/C) disk has been removed with a lathe and a new steel disk pressed on with an interference fit of 0.04mm. For peace of mind I had it balanced after this.
Looks like this:
You can't go larger in outer diameter or the belt will touch the waterpump pulley.
James on the SXOC was so kind to donate a part of his body to science -corpus vivi- sacrificed a pulley and dissected it to reveal its secrets:
I'm using a CA18DET timing belt tensioner to tension the 5-rib SC belt. No noticeable slip nor signs of wear but who knows how long the belt will live.
It might look convenient to build a crankshaft pulley with the SC disc in front of the other ones but that will move forward the fulcrum point of the side force exerted on the pulley by the belt. If you see that there is only about 10mm of crankshaft for the pulley to sit on, I am not at all convinced that this is the way to go.
float_6969 wrote: I have a Ross Race balancer, so I have bolts right on the front that would allow me to mount a pulley easily.
Sounds good. Can you post a picture of this?
Cheers,
Jean