[Roadsters] Maximum Advance and Octane -- how far can I go?

[Matthew A. Smith]

John said: I am looking for others to chime in here to confirm my thoughts,
or to shoot me down if I need corrected.

Bugs: Would you like to shoot me now or wait till you get home. 
Daffy: Shoot him now; shoot him now. 
Bugs: You keep outta this, he doesn't have to shoot you now. 
Daffy: Hah! That's it! Hold it right there! [to audience] Pronoun trouble.
[to Bugs] It's not "he doesn't have to shoot you now", it's "he doesn't have
to shoot me now" 
[Pause] 
Daffy: [angrily] Well, I say he does have to shoot me now!! [to Elmer] So
shoot me now! 
[Elmer obliges and lets him have it]

Hehehehe! Happy Wednesday!
Matt


-----Original Message-----
From: datsun-roadsters-bounces+matthews517=earthlink.net at autox.team.net
[mailto:datsun-roadsters-bounces+matthews517=earthlink.net at autox.team.net]
On Behalf Of jover4x4 at aol.com
Sent: Wednesday, August 20, 2008 1:43 PM
To: nmleeds at mindspring.com; datsun-roadsters at autox.team.net
Subject: Re: [Roadsters] Maximum Advance and Octane -- how far can I go?

Nathanial,

I had my Solex U20 on a dyno at 5000ft with regular gas and saw no
appreciable hp difference between static timing settings of 15 and 20 DBTC.

Octane boost will allow more compression without detonation?however I don't
believe it will?allow you much more power with just a timing change.? 

I.e. If you advance the timing too far you get into timing related
pre-ignition not detonation.? I think the octane boost only helps on the
latter.

I am looking for others to chime in here to confirm my thoughts, or to shoot
me down if I need corrected.

John Over
Denver, CO


-----Original Message-----
From: Nathaniel Leeds <nmleeds at mindspring.com>
To: datsun-roadsters at autox.team.net
Sent: Wed, 20 Aug 2008 11:19 am
Subject: [Roadsters] Maximum Advance and Octane -- how far can I go?



Still tuning,

And now I'm starting to have evil urges. There's a little devil sitting on
my shoulder which wants me to buy a crate of octane boost and crank out my
advance (20+ degrees on my SU carb, Solex cam, U20). What is people's
experiance in this regard. How much maximum advance (mechanical + vacume)
can the U20 take on 91 octane, and then how much more can it take with a
little street-legal octane booster. I know there are standard formulas
depending on the engine, I just don't know what they are.

Also, does someone know where I can find the advance charts for the U20
distributors (plural because I know there are a couple of available curves,
and I don't yet know which mine is). I'd like to get a feeling for what my
maximum theoretical advance is without pissing off the neighbors by running
my engine at 6000 rpms.

Nathaniel Leeds
'69 2000 U20
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