Monkeybasher
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| posted on 31/5/06 at 03:45 PM |
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I think its probably the later eaton chargers with the built in bypass valve versions 4/5. Which doesnt include mine. .
I agree with atomic I think A decompression plate would be a much easier solution than machining pistons.
Is there not something about vauxhall pistons being used or something by the zetec turbo guys to lower compression.
Cheers
Steve
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andyharding
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| posted on 31/5/06 at 03:52 PM |
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It's easy enough to measure and remove same amount from each piston.
They could then be weighed on digital kitchen scales and easiliy balanced to a tolerance of 1g.
The only risk as I see it is making the crown so thin they melt through and that's not going to cause a spectacular blow-up.
Are you a Mac user or a retard?
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andyharding
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| posted on 31/5/06 at 03:54 PM |
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quote:
Originally posted by Monkeybasher
I think its probably the later eaton chargers with the built in bypass valve versions 4/5. Which doesnt include mine..
I agree with atomic I think A decompression plate would be a much easier solution than machining pistons.
Is there not something about vauxhall pistons being used or something by the zetec turbo guys to lower compression.
Cheers
Steve
In that case I think I'd swap it around so the TB is after the charger and plumb in a regualr dump valve.
Are you a Mac user or a retard?
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Monkeybasher
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| posted on 31/5/06 at 06:47 PM |
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quote:
Originally posted by andyharding
quote:
Originally posted by Monkeybasher
I think its probably the later eaton chargers with the built in bypass valve versions 4/5. Which doesnt include mine..
I agree with atomic I think A decompression plate would be a much easier solution than machining pistons.
Is there not something about vauxhall pistons being used or something by the zetec turbo guys to lower compression.
Cheers
Steve
In that case I think I'd swap it around so the TB is after the charger and plumb in a regualr dump valve.
How would the dump valve work, would it be a short phsss, or a long continuous ppppppppppppppphhhhhhhhhhsssssssss.
Could you tell me how to plumb it up. I presume the dump valve would go before the tb, with a vacuum hose to after the throttle body, then either
vent to air or back to before the supercharger inlet???
Steve
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andyharding
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| posted on 31/5/06 at 06:57 PM |
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quote:
Originally posted by Monkeybasher
How would the dump valve work, would it be a short phsss, or a long continuous ppppppppppppppphhhhhhhhhhsssssssss.
Could you tell me how to plumb it up. I presume the dump valve would go before the tb, with a vacuum hose to after the throttle body, then either
vent to air or back to before the supercharger inlet???
Steve
No idea to be honest. A big tissshhh would be nice!
Yes, DV before TB with a vacuum line to after. That way when the DV sees vacuum (ie closed throttle) it vents the excess boost. A recirculating DV
would be quieter.
Are you a Mac user or a retard?
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bimbleuk
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| posted on 1/6/06 at 01:02 PM |
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I can highly recommend the book I mentioned earlier as it covers all the possible install setups and a lot lot more.
With a fixed displacement supercharger such as a roots (Eaton/Mini) or a twin screw unless you are using a clutch you want the TB before the blower.
The bypass valve allows the pressure to equalise either side if the SC when the throttle is shut (or even part closed). The SC just pushes air around
in a circuit but as its not under load its also not heating the air as much either. This also reduces parasitic loses again as the SC is effectively
"free wheeling" when its not required to produce boost.
Turbos (or centrifugal blowers) can more readily work behind the TB as air can flow back through the impellor when you lift off the throttle.
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Marcus
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| posted on 1/6/06 at 02:20 PM |
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Bollox 
I wish I hadn't read this post - I want a supercharged crossflow now!!
Acres of room under the bonnet, and the alternator's on the right (left) side.
I was just getting my head round Megasquirt, now this!!
Bas****s
Marcus
Marcus
Because kits are for girls!!
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bimbleuk
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| posted on 1/6/06 at 07:16 PM |
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Yep superchargers/turbos can be addictive. Several of my previous cars have been either but mostly superchared.
I've had several mini superchargers pass through my hands (still got one under the stairs!) but oddly I've never actually fitted one.
Never liked the bulky design due to the integrated water pump drive.
I've been waiting to fit a Rotrex on my Striker and as my tuning garage have worked on three installs recently with decent results I think its
about to time to go ahead 
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Monkeybasher
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| posted on 1/6/06 at 11:25 PM |
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quote:
Originally posted by Marcus
Bollox
I wish I hadn't read this post - I want a supercharged crossflow now!!
Acres of room under the bonnet, and the alternator's on the right (left) side.
I was just getting my head round Megasquirt, now this!!
Bas****s
Marcus
somebody done it to me and I'm glad.
Once you've sussed the megasquirt its a straight forward move to a supercharger, so much less work and time involved IMO to slap a charger on
than getting megasquirt built, working and understood. I still dont feel nearly as confident as I'd like too.
[Edited on 1/6/06 by Monkeybasher]
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Monkeybasher
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| posted on 1/6/06 at 11:43 PM |
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quote:
Originally posted by bimbleuk
The bypass valve allows the pressure to equalise either side if the SC when the throttle is shut (or even part closed). The SC just pushes air around
in a circuit but as its not under load its also not heating the air as much either. This also reduces parasitic loses again as the SC is effectively
"free wheeling" when its not required to produce boost.
Would a normal recirculating dump valve do the job of a bypass valve? I have searched and searched for bypass valves without much success. I would
prefere one of these because then I could T it in anywhere.
Assuming you can use a recirc dump valve would it T in before the supercharger and have a pipe off to after the charger and the vacuum hose to after
the charger.
...Or T it in after the charger and have a pipe running back to before the charger and vacuum to after the charger.
Also I bought a smaller pulley today for the supercharger. For interest the standard zetec and mini supercharger produce about 5psi ish on mine
anyway. I still need to work out the igntion map too not a strong point for me, more reading ahead.
Steve
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bimbleuk
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| posted on 2/6/06 at 09:54 AM |
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This is the one I ordered from the states and it worked well on my Blitz kit installed on my Celica.
http://www.magnusonproducts.com/bypass.htm
As its just a vacuum operated butterfly valve I don't see why a piston type recirculating dump valve wouldn't work. You could get one in a
scrappy from a factory turbo car to test.
You just need to T in a pipe before and after the supercharger and put the signal/vacuum pipe to the inlet plenum.
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