On my turbo U20 I run cast pistons and no "O" rings and pushes 17 lbs. boost
and I have had no problems with the pistons or the head gasket. But I do
make sure there is no detonation, but even forged pistons will melt under
the heat of detonation. in fact the melting point of a forged piston is not
that much greater than a cast piston it will take just a few seconds more
for it to melt...
Rpms puts more strain on a motor's internal parts than Boost ( a motor
turning 8000 rpms has more load on it's internal parts , than a motor turn
6000 rpms with 14lbs boost ) and with boost you don't need to rev the motor
over 6000 to make HP gains above a normal aspirated motor turn 8000..
Running 14 lbs. boost on a U20 will give you well over 225 HP
a super charger though will suck up some of that HP to drive it , that is
why turbos are better they run off of wasted exhaust gas heat. 50% of the
heat energy created in a engine is pumped out the exhaust pipe.
Mike Kerr
Restoration Products
3730 todrob Ln.
Placerville, CA 95667
Ph# 530-644-6777
Fax# 530-644-6777
E-mail mikekerr@innercite.com
Web; innercite.com/~wolfgang
-----Original Message-----
From: Jim Tyler <toplessdatsun@ga.prestige.net>
To: Roadster List <datsun-roadsters@autox.team.net>
Date: Thursday, May 11, 2000 4:31 PM
Subject: Re: Major Armchair engineering A SuperCharged Roadster??
>
>
>Mike Kerr wrote:
>>
>> have to disagree on the "O": ringing for street use it is not nessasry or
>> desirable, forgded pistons are not nessary either... Both the "O"
ringing
>> and Forged pistions have advantages in a race where getting across the
>> finish line first is the objective.. But for street use where Rpms will
be
>> kept low for engine longevity and low boost settings neither fordged
pistons
>> or "O" ringing are nessary
>
>In general I would agree that for typical street use o-ringing is not
desirable
>and forged pistons are not required.
>
>However, to make the kind of HP gains that would begin to justify the cost
of
>either a turbo efi or a supercharged, you will no longer be in a "typical"
>street application.
>
>I don't get the impression that Daniel wants to spend 2000.00 to add 20 hp
>at 4800 rpms.
>
>To make say 225, I would be surprised if the rpm's or boost really remain
all
>that
>"low" for stock pistons.
>
>Victor can show you how well the 60's quality cast pistons hold up under
>detonation.
>
>
>But either way, I think Daniel and Mike should link up on this, Daniel
only
>wants
>to spend 2K and Mike says the engine doesn't need modifications. Perfect
>match. Keep us posted.
>
>Jim
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