New L88?

[Ethan]

----- Original Message -----
From: "Eric Bryant" <BRYANTE at ghsp.com>
To: <gmecm at diy-efi.org>
Sent: Monday, June 18, 2001 2:17 PM
Subject: RE: New L88?

<cut>

> I thought that hemispherical chambers and two-valve heads don't mix well,
> since it's difficult to fit big valves into small combustion chamber
> volumes.  Even the modern four-valve heads that I've worked with (all
> motorcycle engines, BTW) have evolved from a hemi chamber to one that's
more
> of a cloverleaf shape in order to combine high compression with a decent
> quench band.
>

Sort of my point...chamber design has evolved, but in the case of the SB
Chevy, perhaps in the wrong direction for the wrong reasons. The end result
would not be the original hemi design that may come to mind. I suggest that
the benefit(s) of the geometry is introduced, and there is always recourse
for managing the downsides. Just a school of thought, and of course many
designs are valid.

>
> As far as connecting-rods go, I can only think that there's some hangup at
> GM about placing rings any further towards the top of the piston.  I can
> understand why they wouldn't want the wristpin up into the oil ring groove
> (like on my new LT1 396 with 6" rods), but they could go a bit longer on
the
> rod while still maintaining durability, I'd think.
>
<cut>

You bet...and the benefits are impressive. The LS1 rods are not bad at 6.1"
up from the Gen II SB 5.7", but we would like to see them closer to 6.3",
along with a shorter stroke and larger bore.

Ethan Hall
Performance Research and Development, Inc.
www.performanceresearchonline.com
.





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